Full Title: Conflict of interest: use of pyrethroids and amidines against tsetse and ticks in zoonotic sleeping sickness endemic areas of Uganda

Authors: Kevin Bardosh, Charles Waiswa and Susan C Welburn

Abstract

This work was partially funded by ICONZ

Full Title: Prevalence and Risk Factors Associated with Human Taenia Solium Infections in Mbozi District, Mbeya Region, Tanzania

Authors: Gloria Mwanjali, Charles Kihamia, Deodatus Vitalis Conatus Kakoko, Faustin Lekule, Helena Ngowi, Maria Vang Johansen, Stig Milan Thamsborg, Arve Lee Willingham, III

Abstract

Background: Taenia solium cysticercosis/taeniosis is emerging as a serious public health and economic problem in many developing countries. This study was conducted to determine prevalence and risk factors of human T. solium infections in Mbeya Region, Tanzania.

Methods and Findings: A cross-sectional survey was conducted in 13 villages of Mbozi district in 2009. Sera of 830 people (mean 37.9611.3 years (SD); 43% females) were tested for circulating cysticerci antigen (Ag-ELISA) and antibody (Ab-ELISA). A subset of persons found seropositive by Ag-ELISA underwent computed tomography (CT) scan of the brain for evidence of neurocysticercosis. Stool samples from 820 of the same participants were tested for taeniosis by copro-antigens (copro-Ag-ELISA) and formol-ether concentration technique. Cases of T. solium taeniosis were confirmed serologically by EITB assay (rES38). A questionnaire was used for identification of risk factors. Active cysticercosis by positive Ag-ELISA was found in 139 (16.7%) persons while anti-cysticercal antibodies were detected in 376 (45.3%) persons by Ab-ELISA. Among 55 persons positive for Ag-ELISA undergoing CT scan, 30 (54.6%) were found to have structures in the brain suggestive of neurocysticercosis. Using faecal analysis, 43 (5.2%) stool samples tested positive for taeniosis by copro-Ag-ELISA while Taenia eggs were detected in 9 (1.1%) stool samples by routine coprology. Antibodies specifically against adult T. solium were detected in 34 copro-Ag-ELISA positive participants by EITB (rES38) indicating T. solium taeniosis prevalence of 4.1%. Increasing age and hand washing by dipping in contrast to using running water, were found associated with Ag-ELISA seropositivity by logistic regression. Gender (higher risk in females) and water source were risk factors associated with Ab-ELISA seropositivity. Reported symptoms of chronic severe headaches and history of epileptic seizures were found associated with positive Ag-ELISA (p#0.05).

Conclusion: The present study indicates T. solium infection in humans is highly endemic in the southern highlands of Tanzania.

This paper can be found online at: http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0002102 

Paper In Press by Shaw APM, Torr SJ, Waiswa C, Cecchi G, Wint GRW, Mattioli RC, Robinson TP (2013)

Funding for this work was received from several funders including  FAO’s Pro-poor Livestock Policy Initiative, under a grant from the UK’s Department for International Development (GCP/INT/804/UK) and ICONZ (an EC FP7 project). 

Abstract

Decision-making and financial planning for tsetse control is complex, with a particularly wide range of choices to be made on location, timing, strategy and methods. This paper presents full cost estimates for eliminating or continuously controlling tsetse in a hypothetical area of 10,000 km² located in south-eastern Uganda. Four tsetse control techniques were analysed: (i) artificial baits (insecticide-treated traps/targets), (ii) insecticide-treated cattle (ITC), (iii) aerial spraying using the sequential aerosol technique (SAT) and (iv) the addition of the sterile insect technique (SIT) to the insecticide-based methods (i–iii).

For the creation of fly-free zones and using a 10% discount rate, the field costs per km² came to US$283 for traps (4 traps per km²), US$30 for ITC (5 treated cattle per km² using restricted application), US$380 for SAT and US$758 for adding SIT. The inclusion of entomological and other preliminary studies plus administrative overheads adds substantially to the overall cost, so that the total costs become US$482 for traps, US$220 for ITC, US$552 for SAT and US$993 – 1365 if SIT is added following suppression using another method. These basic costs would apply to trouble-free operations dealing with isolated tsetse populations. Estimates were also made for non-isolated populations, allowing for a barrier covering 10% of the intervention area, maintained for 3 years. Where traps were used as a barrier, the total cost of elimination increased by between 29% and 57% and for ITC barriers the increase was between 12% and 30%.

In the case of continuous tsetse control operations, costs were estimated over a 20-year period and discounted at 10%. Total costs per km² came to US$368 for ITC, US$2114 for traps, all deployed continuously, and US$2442 for SAT applied at 3-year intervals. The lower costs compared favourably with the regular treatment of cattle with prophylactic trypanocides (US$3862 per km² assuming four doses per annum at 45 cattle per km²).

Throughout the study, sensitivity analyses were conducted to explore the impact on cost estimates of different densities of ITC and traps, costs of baseline studies and discount rates.

The present analysis highlights the cost differentials between the different intervention techniques, whilst attesting to the significant progress made over the years in reducing field costs. Results indicate that continuous control activities can be cost-effective in reducing tsetse populations, especially where the creation of fly-free zones is challenging and reinvasion pressure high.

This paper can be found online at http://dx.doi.org/10.1016/j.prevetmed.2012.12.014

DISCONTOOLS  have released two new papers. (click on the title to download)

1.  ‘Approaches to the prioritisation of diseases to focus and prioritise research in animal health: A worldwide review of existing methodologies’ from WP 2

2. ‘A methodology for identification and evaluation of New Technologies in Animal Health’ from WP 4

Find out more about Discontools on their website:  www.discontools.eu

Vincent Jamonneau, Hamidou Ilboudo, Jacques Kaboré, Dramane Kaba, Mathurin Koffi, Philippe Solano, André Garcia, David Courtin, Claude Laveissière, Kouakou Lingue, Philippe Büscher, Bruno Bucheton
doi:10.1371/journal.pntd.0001691

The final outcome of infection by Trypanosoma brucei gambiense, the main agent of sleeping sickness, has always been considered as invariably fatal. While scarce and old reports have mentioned cases of self-cure in untreated patients, these studies suffered from the lack of accurate diagnostic tools available at that time. Here, using the most specific and sensitive tools available to date, we report on a long-term follow-up (15 years) of a cohort of 50 human African trypanosomiasis (HAT) patients from the Ivory Coast among whom 11 refused treatment after their initial diagnosis. In 10 out of 11 subjects who continued to refuse treatment despite repeated visits, parasite clearance was observed using both microscopy and polymerase chain reaction (PCR). Most of these subjects (7/10) also displayed decreasing serological responses, becoming progressively negative to trypanosome variable antigens (LiTat 1.3, 1.5 and 1.6). Hence, in addition to the “classic” lethal outcome of HAT, we show that alternative natural progressions of HAT may occur: progression to an apparently aparasitaemic and asymptomatic infection associated with strong long-lasting serological responses and progression to an apparently spontaneous resolution of infection (with negative results in parasitological tests and PCR) associated with a progressive drop in antibody titres as observed in treated cases. While this study does not precisely estimate the frequency of the alternative courses for this infection, it is noteworthy that in the field national control programs encounter a significant proportion of subjects displaying positive serologic test results but negative results in parasitological testing. These findings demonstrate that a number of these subjects display such infection courses. From our point of view, recognising that trypanotolerance exists in humans, as is now widely accepted for animals, is a major step forward for future research in the field of HAT.

This paper can be found online by clicking here.

Barnes, T S; Deplazes, P; Gottstein, B; et al.
Acta tropica 123 (issue 1) 1-7 Published: July 2012
ISSN: 1873-6254

This paper is based on the experience of the authors, with the aim to define the challenges for Echinococcus granulosus (E.g./CE) diagnosis and control for those countries that may now or in the future be contemplating control of hydatid disease. A variety of methods are available for diagnosis in humans but a universal gold standard is lacking. Diagnosis in definitive hosts can avoid necropsy by the use of methods such as coproantigen detection but test performance is variable between populations. A sylvatic cycle adds challenges in some countries and the epidemiology of the parasite in these hosts is poorly understood. Control by solely administering praziquantel to dogs is not effective in developing countries where the disease is endemic. Additional avenues to pursue include the instigation of participatory planning, use of an existing vaccination for intermediate hosts and development of a vaccine and long-acting anthelmitic implants for definitive hosts. Promoting public acceptance of control of the dog population by humane euthanasia and reduced reproduction is also essential.

For more information see Web of Knowledge

Torgerson, Paul R.; Macpherson, Calum N. L.
Veterinary Parasitology  182 (issue 1):  79-95, Published: 24 Nov 2011
IDS Number: 834YY
ISSN: 0304-4017

Diseases resulting from zoonotic transmission of parasites are common. Humans become infected through food, water, soil and close contact with animals. Most parasitic zoonoses are neglected diseases despite causing a considerable global burden of ill health in humans and having a substantial financial burden on livestock industries. This review aims to bring together the current data available on global burden estimates of parasitic zoonoses and indicate any changes in the trends of these diseases. There is a clear need of such information as interventions to control zoonoses are often in their animal hosts. The costs of such interventions together with animal health issues will drive the cost effectiveness of intervention strategies. What is apparent is that collectively, parasitic zoonoses probably have a similar human disease burden to any one of the big three human infectious diseases: malaria, tuberculosis or HIV in addition to animal health burden. Although the global burden for most parasitic zoonoses is not yet known, the major contributors to the global burden of parasitic zoonoses are toxoplasmosis, food borne trematode infections, cysticercosis, echinococcosis, leishmaniosis and zoonotic schistosomosis. In addition, diarrhoea resulting from zoonotic protozoa may have a significant impact.

For more information see Web of Knowledge

Parasitic worms leave millions of victims paralyzed, epileptic, or worse. So why isn’t anyone mobilizing to eradicate them?
by Carl Zimmer

Discover Magazine’s 15 May edition, section on Mind & Brain Infectious Diseases

The article gives a good overview of the disease and its linkage with epilepsy, with information provided by Dr Theodore Nash at NIH in USA including the estimate of at least 5 million cases of epilepsy caused by NCC worldwide. There is even a nice photo of a “Swiss Cheese” brain infected with NCC accompanying the article.

Link to article:

A Discover Magazine article on neurocysticercosis inspired a ‘News on Livestock and Development Clipping’, on ILRI website.
by Susan MacMillan

The whole article in Discover Magazine can be read at: Hidden epidemic: Tapeworms living inside people’s brains, 15 May 2012 (June 2012 issue).

Simarro PP, Cecchi G, Franco JR, Paone M, Fèvre EM, Diarra A, et al.

Emerg Infect Dis [serial on the Internet]. 2011 Dec
DOI: 10.3201/eid1712.110921

Comprehensive georeference records for human African trypanosomiasis in Cameroon, Central African Republic, Chad, Congo, Equatorial Guinea, and Gabon were combined with human population layers to estimate a kernel-smoothed relative risk function. Five risk categories were mapped, and ≈3.5 million persons were estimated to be at risk for this disease.

This paper is available in the public domain from the journal’s website:

Review

Anna L. Okello, E. Paul J. Gibbs, Alain Vandersmissen, Susan C. Welburn,

Research Article

Kohei Makita, Eric M Fèvre, Charles Waiswa, Mark C Eisler, Michael Thrusfield and Susan C Welburn

BMC Veterinary Research 2011, 7:60

doi:10.1186/1746-6148-7-60

Human brucellosis has been found to be prevalent in the urban areas of Kampala, the capital city of Uganda. A cross-sectional study was designed to generate precise information on the prevalence of brucellosis in cattle and risk factors for the disease in its urban and peri-urban dairy farming systems.

The main conclusion from this study was that vaccination should be targeted at commercial large-scale farms with free-grazing farming to control brucellosis in cattle in and around Kampala city.

The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1746-6148/7/60

Review Article

S. M. S. Afonso, Y. Vaz, L. Neves, A. Pondja, G. Dias, A. L. Willingham III,
M. Vilhena, P. C. Duarte, C. C. Jost and E. V. Noormahomed

Animal Health Research Reviews 12(1); 123–129
ISSN 1466-2523  doi:10.1017/S1000077

This paper critically reviews and summarizes the available scientific and lay literature, and ongoing studies on human and porcine cysticercosis in Mozambique to identify knowledge gaps and direct immediate and long-term research efforts.

The electronic version of this article can be found online by clicking here:

Sue Welburn assesses recent progress in developing the One Health concept,
and where the challenges remain.

• http://veterinaryrecord.bmj.com/content/168/23/614.full

His commentary is entitled ‘La rage humaine vers une meilleure communication entre la santé publique et vétérinaire!’. In this commentary, he argues that physicians should become more actively involved in the fight against
Rabies in light of the ecology of this infection and the role of animals, especially dogs.

Zinsstag proposes that practical measures be introduced including:

• a ‘clinical algorithm’ for the diagnosis of rabies
• Health Education – in schools and of the general public
• a Public Health committment to elimination of rabies via use of the dog rabies vaccine

• Article [119KB]

PLOS NTD April 2011 | Volume 5 | Issue 4 | e950

• Article [184KB]

PLoS Negl Trop Dis 5(1): e927. doi:10.1371/journal.pntd.0000927

Taenia solium cysticercosis is a neglected tropical infection transmitted between humans and pigs. This infection is particularly common in areas where sanitation, hygiene and pig management practices are poor, and can sometimes lead to epilepsy in humans. There is very little information about the importance of this infection in Burkina Faso, even though pork meat is widely consumed in many villages. We conducted a pilot study in three villages: two villages where pig rearing and pork consumption are common (Batondo and Pabré) but with different pig management practices, and one village with limited pig farming and pork consumption (Nyonyogo). Blood tests were done on pigs and information on pig raising was collected from farmers. Our study demonstrated that at least one third of pigs are infected with cysticercosis in villages where they are raised, and, particularly when pigs are left to roam some or all of the time. It also demonstrated that farmers may not be aware of this disease until one of their animals is found to be infected. Thus, the study concluded that there is an urgent need for improving education in order to control this tropical disease.

• http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000927

PLoS Negl Trop Dis 5(1): e941.doi:10.1371/journal.pntd.0000941

Background
Trypanosomiasis is regarded as a constraint on livestock production in Western Kenya where the responsibility for tsetse and trypanosomiasis control has increasingly shifted from the state to the individual livestock owner. To assess the sustainability of these localised control efforts, this study investigates biological and management risk factors associated with trypanosome infections detected by polymerase chain reaction (PCR), in a range of domestic livestock at the local scale in Busia, Kenya. Busia District also remains endemic for human sleeping sickness with sporadic cases of sleeping sickness reported.

Results
In total, trypanosome infections were detected in 11.9% (329) out of the 2773 livestock sampled in Busia District. Multivariable logistic regression revealed that host species and cattle age affected overall trypanosome infection, with significantly increased odds of infection for cattle older than 18 months, and significantly lower odds of infection in pigs and small ruminants. Different grazing and watering management practices did not affect the odds of trypanosome infection, adjusted by host species. Neither anaemia nor condition score significantly affected the odds of trypanosome infection in cattle. Human infective Trypanosoma brucei rhodesiense were detected in 21.5% of animals infected with T. brucei s.l. (29/135) amounting to 1% (29/2773) of all sampled livestock, with significantly higher odds of T. brucei rhodesiense infections in T. brucei s.l. infected pigs (OR = 4.3, 95%CI 1.5-12.0) than in T. brucei s.l. infected cattle or small ruminants.

Conclusions
Although cattle are the dominant reservoir of trypanosome infection it is unlikely that targeted treatment of only visibly diseased cattle will achieve sustainable interruption of transmission for either animal infective or zoonotic human infective trypanosomiasis, since most infections were detected in cattle that did not exhibit classical clinical signs of trypanosomiasis. Pigs were also found to be reservoirs of infection for T. b. rhodesiense and present a risk to local communities.

• http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000941

PLoS Negl Trop Dis 4(12): e823.doi:10.1371/journal.pntd.0000823

• http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000823

PLoS Negl Trop Dis 4(12): e910. doi:10.1371/journal.pntd.0000910

Background
In the developing world where parasitic worm infections are pervasive, preventive chemotherapy is the key strategy for morbidity control. However, local knowledge, attitudes, and practices (KAP) of parasitic worms are poorly understood, although such information is required for prevention and sustainable control.

Methods
We carried out KAP surveys in two rural communities of Côte d’Ivoire that were subjected to school-based and community-based research and control activities. We used qualitative and quantitative methods. The former included observations, in-depth interviews with key informants, and focus group discussions with school children and adults. Quantitative methods consisted of a structured questionnaire administered to household heads.

Principal Findings
Access to clean water was lacking in both communities and only a quarter of the households had functioning latrines. There was a better understanding of soil-transmitted helminthiasis than intestinal schistosomiasis, but community-based rather than school-based interventions appeared to improve knowledge of schistosomiasis. In the villages with community-based interventions, three-quarters of household interviewees knew about intestinal schistosomiasis compared to 14% in the village where school-based interventions were implemented (P<0.001). Whereas two-thirds of respondents from the community-based intervention village indicated that the research and control project was the main source of information, only a quarter of the respondents cited the project as the main source

Conclusions/Significance
Preventive chemotherapy targeting school-aged children has limitations, as older population segments are neglected, and hence lack knowledge about how to prevent and control parasitic worm infections. Improved access to clean water and sanitation is necessary, along with health education to make a durable impact against helminth infections.

• http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000910

PLoS Negl Trop Dis 4(12): e831.doi:10.1371/journal.pntd.0000831

• http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000831

PLoS Negl Trop Dis 4(12): e914. doi:10.1371

Background
The persistent spread of Rhodesian human African trypanosomiasis (HAT) in Uganda in recent years has increased concerns of a potential overlap with the Gambian form of the disease. Recent research has aimed to increase the evidence base for targeting control measures by focusing on the environmental and climatic factors that control the spatial distribution of the disease.

Objectives
One recent study used simple logistic regression methods to explore the relationship between prevalence of Rhodesian HAT and several social, environmental and climatic variables in two of the most recently affected districts of Uganda, and suggested the disease had spread into the study area due to the movement of infected, untreated livestock. Here we extend this study to account for spatial autocorrelation, incorporate uncertainty in input data and model parameters and undertake predictive mapping for risk of high HAT prevalence in future.

Materials and Methods
Using a spatial analysis in which a generalised linear geostatistical model is used in a Bayesian framework to account explicitly for spatial autocorrelation and incorporate uncertainty in input data and model parameters we are able to demonstrate a more rigorous analytical approach, potentially resulting in more accurate parameter and significance estimates and increased predictive accuracy, thereby allowing an assessment of the validity of the livestock movement hypothesis given more robust parameter estimation and appropriate assessment of covariate effects.

Results
Analysis strongly supports the theory that Rhodesian HAT was imported to the study area via the movement of untreated, infected livestock from endemic areas. The confounding effect of health care accessibility on the spatial distribution of Rhodesian HAT and the linkages between the disease’s distribution and minimum land surface temperature have also been confirmed via the application of these methods.

Conclusions
Predictive mapping indicates an increased risk of high HAT prevalence in the future in areas surrounding livestock markets, demonstrating the importance of livestock trading for continuing disease spread. Adherence to government policy to treat livestock at the point of sale is essential to prevent the spread of sleeping sickness in Uganda.

• http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000914

PLoS Negl Trop Dis 4(11): e765. doi:10.1371/journal.pntd.0000765

• http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000765

PLoS One. 2010 Apr 1;5(4):e9968.

Background: Brucellosis is a zoonosis of veterinary, public health and economic significance in most developing countries. Human brucellosis is a severely debilitating disease that requires prolonged treatment with a combination of antibiotics. The disease can result in permanent and disabling sequel, and results in considerable medical expenses in addition to loss of income due to loss of working hours. A study was conducted in Northern Tanzania to determine the risk factors for transmission of brucellosis to humans in Tanzania.

Methods: This was a matched case-control study. Any patient with a positive result by a competitive ELISA (c-ELISA) test for brucellosis, and presenting to selected hospitals with at least two clinical features suggestive of brucellosis such as headache, recurrent or continuous fever, sweating, joint pain, joint swelling, general body malaise or backache, was defined as a case. For every case in a district, a corresponding control was traced and matched by sex using multistage cluster sampling. Other criteria for inclusion as a control included a negative c-ELISA test result and that the matched individual would present to hospital if falls sick.

Results: Multivariable analysis showed that brucellosis was associated with assisted parturition during abortion in cattle, sheep or goat. It was shown that individuals living in close proximity to other households had a higher risk of brucellosis. People who were of Christian religion were found to have a higher risk of brucellosis compared to other religions. The study concludes that assisting an aborting animal, proximity to neighborhoods, and Christianity were associated with brucellosis infection. There was no association between human brucellosis and Human Immunodeficiency Virus (HIV) serostatus. Protecting humans against contact with fluids and tissues during assisted parturition of livestock may be an important means of reducing the risk of transferring brucellosis from livestock to humans. These can be achieved through health education to the communities where brucellosis is common.

• http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0009968

PLoS ONE 2010 5(12): e14188. doi:10.1371/journal.pone.0014188

Background: In Kampala, Uganda, studies have shown a significant incidence of human brucellosis. A stochastic riskassessment involving two field surveys (cattle farms and milk shops) and a medical record survey was conducted to assess the risk of human brucellosis infection through consumption of informally marketed raw milk potentially infected with Brucella abortus in Kampala and to identify the best control options.

Methodology/Principal Findings: In the cattle farm survey, sera of 425 cows in 177 herds in the Kampala economic zone were sampled and tested for brucellosis using a competitive enzyme-linked immunosorbent assay (CELISA). Farmers were interviewed for dairy information. In the milk shop surveys, 135 milk sellers in the urban areas were interviewed and 117 milk samples were collected and tested using an indirect enzyme-linked immunosorbent assay (IELISA). A medical record survey was conducted in Mulago National Referral Hospital for serological test results. A risk model was developed synthesizing data from these three surveys. Possible control options were prepared based on the model and the reduction of risk was simulated for each scenario. Overall, 12.6% (6.8–18.9: 90%CI) of informally marketed milk in urban Kampala was contaminated with B.abortus at purchase and the annual incidence rate was estimated to be 5.8 (90% CI: 5.3–6.2) per 10,000 people. The best control option would be the construction of a milk boiling centre either in Mbarara, the largest source of milk, or in peri-urban Kampala and to ensure that milk traders always sell milk to the boiling centre; 90% success in enforcing these two options would reduce risk by 47.4% (21.6–70.1: 90%CI) and 82.0% (71.0–89.0: 90%CI), respectively.

Conclusion/Significance: This study quantifies the risk of human brucellosis infection through informally marketed milk and estimates the incidence rate in Kampala for the first time; risk-based mitigation strategies are outlined to assist in developing policy.

Citation: Makita K, Fèvre EM, Waiswa C, Eisler MC, Welburn SC (2010) How Human Brucellosis Incidence in Urban Kampala Can Be Reduced Most Efficiently? A Stochastic Risk Assessment of Informally-Marketed Milk. PLoS ONE 5(12): e14188. doi:10.1371/journal.pone.0014188

• http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0014188

Charles Waiswa and John David Kabasa, 2010, Journal of Veterinary and Medical Education 37(3) 276-281

By 2006, the acute and zoonotic Tripanosoma brucei rhodesiense sleeping sickness in Uganda was spreading northward, leading to fear of a merger with the chronic Tripanosoma brucei gambiese type that affects people in the northwest of the country. Eliminating infection in cattle was urgent because they had been confirmed to be spreading the zoonotic type, and eliminating infection would reduce the animal reservoir and subsequently reduce transmission of sleeping sickness. In this article, we describe how the staff and students of the Faculty of Veterinary Medicine, Makerere University, adjusted their approach to training veterinary students who could provide the urgently needed manpower to enable the community to halt the disease’s spread. Because it was not usual for university staff and students to implement disease control activities, the government of Uganda had to delegate this responsibility to Makerere University. In turn, the university had to explore available opportunities in its training and outreach mandates. A model was developed that proved to be an effective hands-on training strategy while helping to control a disease that was threatening the health of people in a community that was just recovering from an armed rebellion. In total, 66 students and supervisors participated in the 10-week-long mass treatment activities in the target area and treated more than 190,000 out of 220,000 targeted (>86%) cattle with diminazene aceturate and deltamethrin. Also, the graduates’ performance improved, as indicated by 43.5% of graduates securing employment within less than a month after completing the course.

• Waiswa / Kabasa Paper [PDF 156KB]

Neurocysticercosis (NCC) is a parasitic infection of the brain caused by the tapeworm Taenia solium, which infects humans and pigs. There have been increasing case reports and epidemiological studies on this disease, but its global frequency has never been determined, partly due to the fact that blood tests are not very good for the diagnosis of
NCC. We present here a systematic review of the literature on the frequency of NCC diagnosed with neuroimaging worldwide. Overall, 565 articles were retrieved and 290 (51%) selected for further review. Of those, only 26 had information valid enough to estimate the frequency of NCC in various populations. Only one study estimated the prevalence of NCC in the general population. The most striking finding was that the proportion of NCC among persons with epilepsy was very consistent and estimated at 29.6% (95%CI: 23.5%–36.1%) from 12 studies conducted in Latin America, Sub-Saharan Africa and Southeast Asia. A reinforcement of the suggested universal guidelines for the diagnostic process, declaring NCC an international reportable disease and standardizing procedures for data collection could improve our understanding of the frequency of NCC worldwide and hence its global burden.

• Ndimubanzi et al.Systematic Review NCC Frequency [PDF 2.59MB]

Sleeping sickness (human African trypanosomiasis – HAT) is a disease transmitted by tsetse flies and is always fatal if left untreated. The disease occurs in foci affecting poor communities with limited access to health service provision and as such the disease is often left undiagnosed, mistaken for more common afflictions. Even if diagnosed, sleeping sickness is costly to treat, both for health services and patients and their families in terms of costs of diagnosis, transport, hospital care, and the prolonged period of convalescence. Here we estimate the health burden of the “acute form” T. b. rhodesiense sleeping sickness in Urambo District, Tanzania in terms of Disability Adjusted Life Years (DALYs), the yardstick commonly used by policy makers to prioritize disease management practices, representing a year of healthy life lost to disease. In this single district, the burden of the disease over one year was estimated at 979 DALYs and the estimated monetary costs to health services for the 143 treated patients at US$ 11,841 and to the patients themselves at US$ 3,673 for direct medical costs and US$ 9,781 for indirect non-medical costs. Sleeping sickness thus places a considerable burden on the affected rural communities and health services.

• http://www.plosntds.org/doi/pntd.0000868

PLoS Negl Trop Dis 4(11): e865.

Human African trypanosomiasis (HAT) is a disease of the rural poor in sub-Saharan Africa where diagnostic laboratories are scarce and often ill equipped. Specific LAMP (loop-mediated isothermal amplification) tests for HAT have been developed and represent a significant step forward in the search for simple, sensitive and reliable diagnosis. Easy, accurate and reliable methods to read the results of these tests are critical and several simple methods have been developed. In this study, four methods were compared including three different colour change methods, and one in which the reaction turned from clear to cloudy. The hydroxynaphthol blue method involving a colour change, from violet to sky blue, was easy to see, the test is cheap to use and the results were largely agreed upon by 33 independent observers.

• http://www.plosntds.org/doi/pntd.0000865

• Commentary: Reducing the global burden of rabies
• by Deborah J. Briggs
• Global Alliance for Rabies Control
• International Health 2 (2010) 161–162

Download the PDF to read this article.

• Reducing Burden [PDF 123KB]
• http://www.elsevier.com/locate/inhe

PLoS Negl Trop Dis 4(9): e817. doi:10.1371/journal.pntd.0000817

Taenia solium is a parasite that can affect both humans and pigs, causing important economic losses in pig production and being the main cause of acquired epilepsy in endemic areas. However, the parasite has been neglected in many African countries and particularly in the Democratic Republic of Congo (DRC), where recent data are non-existent. The present study is part of a first initiative to assess whether cysticercosis is actually present in DRC and to estimate its potential economic and public health importance. Focusing our work on porcine cysticercosis, we demonstrated high prevalence figures of active infections in villages in a rural area of DRC and in markets in the city of Kinshasa. Moreover, the intensity of infection was higher in pigs sampled in villages as compared to pigs sampled on urban markets. Preliminary surveys conducted in parallel in both study sites suggest an effect of pork trade on the transmission of the parasite selecting highly infected pigs at village level.

Citation: Praet N, Kanobana K, Kabwe C, Maketa V, Lukanu P, et al. (2010) Taenia solium Cysticercosis in the Democratic Republic of Congo: How Does Pork Trade Affect the Transmission of the Parasite? PLoS Negl Trop Dis 4(9): e817. doi:10.1371/journal.pntd.0000817

• http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000817

PLOSNTD February 2010 | Volume 4 | Issue 2 | e626

Elimination of canine rabies has been achieved in some parts of the world, but the disease still kills many thousands of people each year in Africa. Here we counter common arguments given for the lack of effective canine rabies control in Africa presenting detailed data from a range of settings. We conclude that rabies substantially affects public and animal health sectors, hence regional and national priorities for control ought to be higher, for practical purposes domestic dogs are the sole maintenance hosts and main source of infection for humans throughout most of Africa and Asia and sufficient levels of vaccination coverage in domestic dog populations should lead to elimination of canine rabies in most areas, the vast majority of domestic dog populations across sub-Saharan Africa are accessible for vaccination with community sensitization being of paramount importance for the success of these programs, improved local capacity in rabies surveillance and diagnostics will help evaluate the impact of control and elimination efforts, and sustainable resources for effective dog vaccination campaigns are likely to be available through the development of intersectoral financing schemes involving both medical and veterinary sectors.

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• Zoonotic Larval Cestode Infections [PDF 446KB]
• http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000626

Author: Anna Holzscheiter | June 22, 2010, Infection Research

It was about a month after ‘patient zero’, 5-year old Edgar Hernandez from Mexico, was registered as the first official case of so called ‘swine flu’ that the WHO raised its pandemic warning level to 5, that is one level below a full-scale global pandemic. Last year’s out-break of the global influenza A pandemic (H1N1) with a predicted historical death toll once again proved that in our globalised world viruses cross borders in no time. It exhibited the difficulties of governments to effectively control sudden outbreaks of highly infectious diseases at a time where the mobility of people is higher than ever.

• Complete Document [PDF 709KB]

Annals of Tropical Medicine & Parasitology, Vol. 103, No. 5, 401–411 (2009)

Late in 2007, veterinary, medical and anthropological professionals from Europe and Africa met in a 2-day workshop in Pretoria, South Africa, to evaluate the burden, surveillance and control of zoonotic tuberculosis and brucellosis in sub-Saharan Africa. Keynote presentations reviewed the burden of these diseases on human and livestock health, the existing diagnostic tools, and the available control methods. These presentations were followed by group discussions and the formulation of recommendations.

The presence of Mycobacterium bovis and Brucella spp. in livestock was considered to be a serious threat to public health, since livestock and animal products are the only source of such infections in human beings. The impact of these pathogens on human health appears to be relatively marginal, however, when compared with Mycobacterium tuberculosis infections and drug resistance, HIV and malaria. Appropriate diagnostic tools are needed to improve the detection of M. bovis and Brucella spp. in humans. In livestock, the ‘test-and-slaughter’ approach and the pasteurization of milk, which have been used successfully in industrialized countries, might not be the optimal control tools in Africa. Control strategies should fit the needs and perceptions of local communities. Improved intersectoral and international collaboration in surveillance, diagnosis and control, and in the education of medical and veterinary personnel, are advocated.

• Complete Document [PDF 111KB]

Parasites & Vectors 2010, 3:51 (11 June 2010)

A previously described Taenia saginata HDP2 DNA sequence, a 4-kb polymorphic fragment, was previously used as the basis for developing PCR diagnostic protocols for the species-specific discrimination of T. saginata from T. solium and for the differentiation of T. saginata from T. asiatica. The latter was shown subsequently to lack the required specificity, so we undertook genetic studies of the HDP2 sequence from T. saginata and T. asiatica to determine why, and to develop a novel HDP2-PCR protocol for the simultaneous unambiguous identification of human taeniids. Sequencing and further analysis of the HDP2 DNA fragments of 19 Asiatic isolates of T. saginata and T. asiatica indicated that the HDP2 sequences of both species exhibited clear genomic variability, due to polymorphic variable fragments, that could correspond to the non-transcribed region of ribosomal DNA. This newly observed polymorphism allowed us to develop a novel, reproducible and reliable HDP2-PCR protocol which permitted the simultaneous discrimination of all T. saginata and T. asiatica isolates examined. This species-specific identification was based on, and facilitated by, the clear size difference in amplicon profiles generated: fragments of 1300 bp, 600 bp and 300 bp were produced for T. asiatica, amplicons of 1300 bp and 300 bp being obtained for T. saginata. Control T. solium samples produced one amplicon of 600 bp with the HDP2-PCR protocol. The assay has the potential to prove useful as a diagnostic tool in areas such as South East Asia where T. saginata, T. asiatica and T. solium coexist.

• Provisional PDF [PDF 1.1MB]

Parasites & Vectors 2010, 3:47 (26 May 2010)

Background: Tsetse flies (Diptera: Glossinidae) are vectors of trypanosomes that cause sleeping sickness in humans and nagana in livestock across sub-Saharan Africa. Tsetse control strategies rely on a detailed understanding of the epidemiology and ecology of tsetse together with genetic variation within and among populations. High-resolution nuclear genetic markers are useful tools for elucidation of the genetic basis of phenotypic traits. In this study amplified fragment length polymorphism (AFLP) markers were developed to analyze genetic variation in Glossina morsitans morsitans from laboratory and field-collected populations from Zimbabwe.

Results: A total of seven hundred and fifty one loci from laboratory and field populations of G. m. morsitans from Zimbabwe were genotyped using AFLP with seven primer combinations. Analysis identified 335 polymorphic loci. The two populations could be distinguished by cluster and principal components analysis (PCA) analysis, indicating that AFLP markers can be used to separate genetically similar populations; at the same time differences observed between laboratory and field populations were not very great. Among the techniques investigated, the use of acetone was the most reliable method of preservation of tsetse for subsequent extraction of high molecular weight DNA. An interesting finding was that AFLP also enabled robust within-population discrimination of male and female tsetse flies due to their different X chromosome DNA complements.

Conclusions: AFLP represents a useful additional tool to add to the suite of techniques currently available for the genetic analysis of tsetse populations and represents a useful resource for identification of the genetic basis of important phenotypic traits.

• Provisional PDF [PDF 438KB]

PLOS Neglected Tropical diseases – February 2009 | Volume 3 | Issue 2 | e319

Recent efforts, including the launching of PLoS Neglected Tropical Diseases, have begun to bring attention to conditions now broadly referred to as neglected tropical diseases (NTDs). Many of these diseases, which affect the socioeconomically disad- vantaged of the world, had not been thoroughly examined and included in large-scale burden assessment undertak- ings, such as the Global Burden of Disease Study, and had not been prioritized at a regional or global level. Recently, global partnerships have been developed that are pushing for inclusion of NTDs in infectious disease research and disease control initiatives. However, an important group of disease-causing organisms has often been excluded, namely the zoonotic larval cestodes.

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• Zoonotic Larval Cestode Infections [PDF 78KB]

PLOS NTD May 2010 | Volume 4 | Issue 5 | e609

The recent announcement that WHO has approved the use of a combination of nifurtimox and eflornithine to treat chronic Gambian sleeping sickness, caused by Trypanosoma brucei gambiense, is a welcome step in the seemingly interminable process of searching for less toxic drugs to treat this devastating disease. Arsenical drugs were first used in 1905; melarsoprol remains the drug most frequently used for late stage disease and is a drug for which resistance is now a major problem.

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• Controlling Sleeping Sickness – “When Will They Ever Learn?” [PDF 78KB]

Emergence of bovine tuberculosis (TB) in wildlife in southern Africa has implications not only for the conservation of the wildlife species affected but also for the health of humans and livestock living at the wildlife-livestock-human interface. Bovine TB in South Africa’s Kruger National Park was first found in African buffaloes (Syncerus caffer) in 1990 and likely entered the park by cattle-to-buffalo transmission. Bovine TB infection has been spreading northward; in 2003, infection was confirmed in a buffalo ≈60 km south of the Limpopo River. In 2005, a case was confirmed only 6 km south of the river (D. Keet, unpub. data). In 2008, we isolated Mycobacterium bovis from African buffaloes in Zimbabwe…. The management implications of bovine TB in buffaloes in Gonarezhou National Park are considerable. Once bovine TB is established in a native free-ranging maintenance host, eradication is unlikely. Evaluation of the prevalence and distribution of the infection in wildlife and livestock populations on the Zimbabwe side of the Great Limpopo Transfrontier Conservation Area is urgently needed. Control options in wildlife are limited, but chances of success are greater if control measures are initiated at the early stage of disease spread into a new area. Adequate risk-mitigation strategies should be developed and implemented to reduce the risk for bovine TB transmission to livestock and humans living at the periphery of the unfenced Gonarezhou National Park. Failure to promptly assess the situation and adopt appropriate measures would have far-reaching conservation, economic, and public health consequences, not only for Zimbabwe but also for the political and social acceptance of the transfrontier conservation areas in southern Africa.

• See http://www.cdc.gov/EID/content/16/5/884.htm.

Plos One. 5(1): e8628. doi:10.1371/journal.pone.0008628

African animal trypanosomiasis is caused by a range of tsetse transmitted protozoan parasites including Trypanosoma vivax, Trypanosoma congolense and Trypansoma brucei. In Western Kenya and other parts of East Africa two subspecies of T. brucei, T.b. brucei and the zoonotic T.b. rhodesiense, co-circulate in livestock. A range of polymerase chain reactions (PCR) have been developed as important molecular diagnostic tools for epidemiological investigations of T. brucei s.l. in the animal reservoir and of its zoonotic potential. Quantification of the relative performance of different diagnostic PCRs is essential to ensure comparability of studies. This paper describes an evaluation of two diagnostic test systems for T. brucei using a T. brucei s.l. specific PCR [1] and a single nested PCR targeting the Internal Transcribed Spacer (ITS) regions of trypanosome ribosomal DNA [2]. A Bayesian formulation of the Hui-Walter latent class model was employed to estimate their test performance in the absence of a gold standard test for detecting T. brucei s.l. infections in ear-vein blood samples from cattle, pig, sheep and goat populations in Western Kenya, stored on Whatman FTA cards. The results indicate that the system employing the T. brucei s.l. specific PCR (Se₁ = 0.760) had a higher sensitivity than the ITS-PCR (Se₂ = 0.640); both have high specificity (Sp₁ = 0.998; Sp₂ = 0.997). The true prevalences for livestock populations were estimated (p_cattle = 0.091, p_pigs = 0.066, p_goats = 0.005, p_sheep = 0.006), taking into account the uncertainties in the specificity and sensitivity of the two test systems. Implications of test performance include the required survey sample size; due to its higher sensitivity and specificity, the T. brucei s.l. specific PCR requires a consistently smaller sample size than the ITS-PCR for the detection of T. brucei s.l. However the ITS-PCR is able to simultaneously screen samples for other pathogenic trypanosomes and may thus be, overall, a better choice of test in multi-organism studies.

• No Gold Standard Estimation of the Sensitivity and Specificity of Two Molecular Diagnostic Protocols for Trypanosoma brucei spp. in Western Kenya [PDF 651KB]

Neglected and endemic zoonoses | Ian Maudlin, Mark Eisler and Susan Welburn

Endemic zoonoses are found throughout the developing world, wherever people live in close proximity to their animals, affecting not only the health of poor people but often also their livelihoods through the health of their livestock. Unlike newly emerging zoonoses that attract the attention of the developed world, these endemic zoonoses are by comparison neglected. This is, in part, a consequence of under-reporting, resulting in underestimation of their global burden, which in turn artificially downgrades their importance in the eyes of administrators and funding agencies. The development of cheap and effective vaccines is no guarantee that these endemic diseases will be eliminated in the near future. However, simply increasing awareness about their causes and how they may be prevented—often with very simple technologies—could reduce the incidence of many endemic zoonoses. Sustainable control of zoonoses is reliant on surveillance, but, as with other public-sector animal health services, this is rarely implemented in the developing world, not least because of the lack of sufficiently cheap diagnostics. Public–private partnerships have already provided advocacy for human disease control and could be equally effective in addressing endemic zoonoses.

• Philosophical Transactions B: Review

PLOS NTD April 2010 | Volume 4 | Issue 4 | e652

Background: Porcine cysticercosis is caused by a zoonotic tapeworm, Taenia solium, which causes serious disease syndromes in human. Effective control of the parasite requires knowledge on the burden and pattern of the infections in order to properly direct limited resources. The objective of this study was to establish the spatial distribution of porcine cysticercosis in Mbulu district, northern Tanzania, to guide control strategies.

Methodology/Principal Findings: This study is a secondary analysis of data collected during the baseline and follow-up periods of a randomized community trial aiming at reducing the incidence rate of porcine cysticercosis through an educational program. At baseline, 784 randomly selected pig-keeping households located in 42 villages in 14 wards were included. Lingual examination of indigenous pigs aged 2–12 (median 8) months, one randomly selected from each household, were conducted. Data from the control group of the randomized trial that included 21 of the 42 villages were used for the incidence study. A total of 295 pig-keeping households were provided with sentinel pigs (one each) and reassessed for cysticercosis incidence once or twice for 2–9 (median 4) months using lingual examination and antigen ELISA. Prevalence of porcine cysticercosis was computed in Epi Info 3.5. The prevalence and incidence of porcine cysticercosis were mapped at household level using ArcView 3.2. K functions were computed in R software to assess general clustering of porcine cysticercosis. Spatial scan statistics were computed in SatScan to identify local clusters of the infection. The overall prevalence of porcine cysticercosis was 7.3% (95% CI: 5.6, 9.4; n=784). The K functions revealed a significant overall clustering of porcine cysticercosis incidence for all distances between 600 m and 5 km from a randomly chosen case household based on Ag-ELISA. Lingual examination revealed clustering from 650 m to 6 km and between 7.5 and 10 km. The prevalence study did not reveal any significant clustering by this method. Spatial scan statistics found one significant cluster of porcine cysticercosis prevalence (P = 0.0036; n = 370). In addition, the analysis found one large cluster of porcine cysticercosis incidence based on Ag-ELISA (P=0.0010; n=236) and two relatively small clusters of incidence based on lingual examination (P = 0.0012 and P = 0.0026; n = 241). These clusters had similar spatial location and included six wards, four of which were identified as high risk areas of porcine cysticercosis.

Conclusion/Significance: This study has identified local clusters of porcine cysticercosis in Mbulu district, northern Tanzania, where limited resources for control of T. solium could be directed. Further studies are needed to establish causes of clustering to institute appropriate interventions.

• Spatial Clustering of Porcine Cysticercosis in Mbulu District, Northern Tanzania [PDF 4.3MB]

This volume includes the following articles: Addressing Zoontotic Diseases at the Animal Human Ecosystem Interface; Drivers of Emerging Zoonotic Disease; One Health Making One Health Operational; Funding Needs and Funding Mechanisms; Economic Losses from Zoonotic Diseases and Basic Assumptions Regarding Financing Requirements; Contributing to One World One Health: A strategic framework for reducing risks of infectious diseases at the Animal Human Ecosystem Interface and One World One Health: From Ideas to Action.

• The World Bank Report No 50833-GLB [PDF 756KB]

PLOS NTD March 2009 | Volume 3 | Issue 3 | e406

Taenia solium cysticercosis is an important zoonosis in many developing countries. Human neurocysticercosis is recognised as an important cause of epilepsy in regions where the parasite occurs. However, it is largely underreported and there is a lack of data about the disease burden. Because a body of information on human and porcine cysticercosis in Cameroon is becoming available, the present study was undertaken to calculate the impact of this neglected zoonosis. Both the cost and Disability Adjusted Life Year (DALY) estimations were applied. All necessary parameters were collected and imported in R software. Different distributions were used according to the type of information available for each of the parameters.

Based on a prevalence of epilepsy of 3.6%, the number of people with neurocysticercosis-associated epilepsy was estimated at 50,326 (95% CR 37,299–65,924), representing 1.0% of the local population, whereas the number of pigs diagnosed with cysticercosis was estimated at 15,961 (95% CR 12,320–20,044), which corresponds to 5.6% of the local pig population. The total annual costs due to T. solium cysticercosis in West Cameroon were estimated at 10,255,202 Euro (95% CR 6,889,048–14,754,044), of which 4.7% were due to losses in pig husbandry and 95.3% to direct and indirect losses caused by human cysticercosis. The monetary burden per case of cysticercosis amounts to 194 Euro (95% CR 147–253). The average number of DALYs lost was 9.0 per thousand persons per year (95% CR 2.8–20.4).

This study provides an estimation of the costs due to T. solium cysticercosis using country-specific parameters and including the human as well as the animal burden of the zoonotic disease. A comparison with a study in South Africa indicates that the cost of inactivity, influenced by salaries, plays a predominant role in the monetary burden of T. solium cysticercosis. Therefore, knowing the salary levels and the prevalence of the disease might allow a rapid indication of the total cost of T. solium cysticercosis in a country. Ascertaining this finding with additional studies in cysticercosisendemic countries could eventually allow the estimation of the global disease burden of cysticercosis. The estimated number of DALYs lost due to the disease was higher than estimates already available for some other neglected tropical diseases. The total estimated cost and number of DALYs lost probably underestimate the real values because the estimations have been based on epilepsy as the only symptom of cysticercosis.

• The Disease Burden of Taeniasolium Cysticercosis in Cameroon [PDF 192KB]

February 2010 | Volume 4 | Issue 2 | e594

Taenia solium is an important zoonosis in many developing countries. Cysticercosis poses a serious public health risk and incurs sizeable economic losses to pig production. Because data on the epidemiology of porcine cysticercosis in Mozambique are scarce, the present study was conducted to determine the prevalence and risk factors for porcine cysticercosis. In this paper a cross-sectional survey was carried out in 11 villages in Angónia district, Tete province in northwestern Mozambique. Between September and November, 2007, a total of 661 pigs were tested serologically and examined by tongue inspection. Serum samples were tested for the presence of circulating parasite antigen using a monoclonal antibody-based sandwich enzyme-linked immunosorbent assay (Ag-ELISA). In addition, a questionnaire survey to collect information on pig production, occurrence and transmission of porcine cysticercosis, risk factors and awareness of porcine cysticercosis was conducted in the selected households from which pigs were sampled. Two hundred thirty-one samples (34.9%) were found positive by the Ag-ELISA, while by tongue inspection on the same animals cysticerci were detected in 84 pigs (12.7%). Increasing age (OR = 1.63; 95% CI = 1.13–2.37) and free-range pig husbandry system (OR = 3.81; 95% CI = 2.08–7.06) were important risk factors for porcine cysticercosis in the district. The present findings indicate that porcine cysticercosis is endemic in the region, and that increasing pig age and pig husbandry practices contribute significantly to porcine cysticercosis transmission. Further epidemiological studies on the prevalence and transmission of porcine cysticercosis in rural communities in Mozambique are needed to enable collection of more baseline data and implementation of effective control strategies within the country.

• Pondja et al Plos 2010 [PDF 100KB]
• http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000594

Human rabies in developing countries can be prevented through interventions directed at dogs. Potential cost-savings for the public health sector of interventions aimed at animal-host reservoirs should be assessed. The cost-effectiveness of mass dog vaccination was compared to postexposure prophylaxis (PEP), which is the current practice in Chad. PEP does not reduce future human exposure. Its cost-effectiveness is estimated at US $46 per disability adjusted life-years averted. Cost-effectiveness for PEP, together with a dog-vaccination campaign, breaks even with cost-effectiveness of PEP alone after almost 5 years. Beyond a time-frame of 7 years, it appears to be more cost-effective to combine parenteral dog-vaccination campaigns with human PEP compared to human PEP alone.

• Rabies Control PNAS [PDF 900KB]

PlosOne December 2009 | Volume 4 | Issue 12 | e8215

Bovine tuberculosis (BTB) today primarily affects developing countries. In Africa, the disease is present essentially on the whole continent; however, little accurate information on its distribution and prevalence is available. Also, attempts to evaluate diagnostic tests for BTB in naturally infected cattle are scarce and mostly complicated by the absence of knowledge of the true disease status of the tested animals. However, diagnostic test evaluation in a given setting is a prerequisite for the implementation of local surveillance schemes and control measures.

The investigators subjected a slaughterhouse population of 954 Chadian cattle to single intra-dermal comparative cervical tuberculin (SICCT) testing and two recently developed fluorescence polarization assays (FPA). Using a Bayesian modeling approach we computed the receiver operating characteristic (ROC) curve of each diagnostic test, the true disease prevalence in the sampled population and the disease status of all sampled animals in the absence of knowledge of the true disease status of the sampled animals. In our Chadian setting, SICCT performed better if the cut-off for positive test interpretation was lowered from 0.4 mm (OIE standard cut-off) to 0.2 mm. Using this cut-off, SICCT showed a sensitivity and specificity of 66% and 89%, respectively. Both FPA tests showed sensitivities below 50% but specificities above 90%. The true disease prevalence was estimated at 8%. Altogether, 11% of the sampled animals showed gross visible tuberculous lesions.

Modelling of the BTB disease status of the sampled animals indicated that 72% of the suspected tuberculosis lesions detected during standard meat inspections were due to other pathogens than Mycobacterium bovis. These results have important implications for BTB diagnosis in a high incidence sub-Saharan African setting and demonstrate the practicability of our Bayesian approach for diagnostic test evaluation.

• Mueller Bayesian ROC BTB PLOS One 2009 [PDF 156KB]

“A ‘One Health’ Approach to Address Emerging Zoonoses: The HALI Project in Tanzania” – Mazet JAK, Clifford DL, Coppolillo PB, Deolalikar AB, Erickson JD, Kazwala RR. 2009, PLoS Med 6(12): e1000190. doi:10.1371/journal.pmed.1000190

In PLoS Medicine, Jonna Mazet (University of California, Davis) and colleagues describe their work in the Tanzania-based HALI Project, which adopts the “One Health” approach to address emerging zoonoses, recognizing the interconnectedness of human, animal, and environmental health. There is a strong need for integrated health approaches, the authors argue, because explosive human population growth and environmental changes have resulted in increased numbers of people living in close contact with wild and domestic animals. “Integrated policy interventions that simultaneously and holistically address multiple and interacting causes of poor human health- unsafe and scarce water, lack of sanitation, food insecurity, and close proximity between animals and humans- will yield significantly larger health benefits than policies that target each of these factors individually and in isolation,” the authors say. See here for the complete paper.

New paper on cattle movements and the spread of trypanosomiasis – “Spatial Predictions of Rhodesian Human African Trypanosomiasis (Sleeping Sickness) Prevalence in Kaberamaido and Dokolo, Two Newly Affected Districts of Uganda.” Batchelor NA, Atkinson PM, Gething PW, Picozzi K, Fèvre EM, Kakembo ASL, Welburn SC. 2009. PLoS Negl Trop Dis 3(12): e563. doi:10.1371/journal.pntd.0000563

“Human African Trypanosomiasis (HAT) or sleeping sickness is a parasitic disease of humans, transmitted by the tsetse fly. There are two different forms of HAT: Rhodesian (in eastern sub-Saharan Africa), which also affects wild and domestic animals, and Gambian (in western and central sub-Saharan Africa). Diagnosis and treatment of the two diseases differ, and disease characterisation is based on prior knowledge of known geographical disease distributions. Presently, the two forms of HAT do not overlap in any area: Uganda is the only country which sustains active transmission of both types.

In recent years, Rhodesian HAT has spread into areas of Uganda that had not previously been affected, thus narrowing the gap between areas of Rhodesian and Gambian HAT transmission. This spread has raised concerns of a potential overlap of the two types of the disease, which would severely complicate their diagnosis and treatment. Earlier work indicated that Rhodesian HAT was introduced to Soroti district due to the movement of untreated cattle from affected areas. Here we show that the continued spread of HAT in Uganda (to a further 2 districts) may also have occurred due to cattle movements, despite legal requirements to treat livestock from affected areas prior to sale at markets. These findings can assist in the targeting of HAT control efforts in Uganda and show that the stringent implementation of animal treatments at livestock markets should be a priority.” See here for the complete paper.

I am sure that most ICONZ partners and scientists are aware of the open access journal PLoS NTD. PLoS NTD already has an impact factor of 4.2 – the highest for specialist Tropical Medicine and is worth consideration for publication of outputs from ICONZ. Please see the attached pdf regarding take up of articles and promotion amongst other media organs.

“Both the print and electronic media have been unusually receptive to reporting on scientific results published in PLoS Neglected Tropical Diseases Information about our scientific findings and frontmatter pieces has appeared frequently and regularly in general scientific and medical journals such as Science, Nature, and The Lancet, as well as high-profile lay publications such as the New York Times, Los Angeles Times, Reuters, AP, USA Today, Wall Street Journal, Financial Times, and The Economist, among others”

“We feel that this intensive media coverage has also provided an important advocacy role in getting NTDs onto the agendas of a number of international agencies, such as the United Nations, the World Health Organization, and the governments representing the Group of Eight (G8) countries, including some nations that have provided substantial donor support”

Sue Welburn WP leader 12

• Editorial [PDF 72KB]
• http://www.plosntds.org/

See presentation by Isabel Minguez Tudela and associated presentation by Francois Meslin.

• Draft Conference Programme [PDF 40KB]