Search

Background : In Cote d'Ivoire, just as in the majority of developing countries, rabies cases are underestimated. The official data are based on passive surveillance studies which cannot provide true estimates. Therefore, the economic and health burden of rabies is underestimated. To be able to better estimate the true burden of rabies, this study looked at surveillance data of bite records and household survey. Methodology : The data was collected from a cross-sectional survey of 8004 households, of which 4002 were in the Department of Bouake and 4002 in the Department of San Pedro. Further data was collected from Human Rabies control centres and from the respective veterinary services. We estimate the burden of rabies through data from the bites surveillance records. Human deaths from rabies were estimated using a series of probability steps to determine the likelihood of clinical rabies in a person after being bitten by a suspected rabid dog. Monte Carlo simulations of a series of interconnected probabilities were used to estimate the rabies burden in the country. Results : The number of deaths from rabies was estimated at 637deaths per year [95% CI 442-849] and human mortality from rabies was estimated at 2.61 per 100’000 [95% CI 1.81-3.56], which represents 24-47 times more cases than the official data. Deaths due to rabies are responsible for 23252 Disability Adjusted Life Years (DALY) lost each year [95% CI 16122-30969]. The estimated annual cost of rabies is 40.15 million USD [95% CI 27.8-53.4]. Overall, 99% of the cost was due to premature deaths. The cost of post-exposure prophylaxis was estimated at 1.6 million USD and represented 1% of the overall cost of rabies. Conclusion : This study highlights the underreporting of rabies cases by the official health information system in Cote d'Ivoire and the annual financial losses related to rabies are equivalent to the estimated cost of the elimination of rabies by 2030. Thus, investing in the fight against in Cote d'Ivoire will be cost effective.

Rabies is the most dreaded neglected zoonosis worldwide. It affects mostly developing countries with limited access to post-exposure prophylaxis and a low coverage of dog vaccination. Objective This study estimates the burden of human rabies in Mali from the extrapolation of animal bite surveillance, mostly dogs, in the region of Sikasso and the District of Bamako in 2016 and 2017. Material and methods Monte Carlo simulations of a series of interconnected probabilities were used to estimate the burden of rabies. The data was collected from cross-sectional surveys of 8775 households of which 4172 were in the District of Bamako and 4603 in the region of Sikasso. Further data was collected in health centres and from the respective veterinary services. Results We estimate that in the year 2016 133 [95% Confidence Interval (95%CI) 87-186] people died and that 5’366 [95%CI 3’510-7’504] years of life (YLL) were lost and in 2017 et 136 [95%CI 96-181] people died and that 5530 [IC 95% 3’913-7’377] YLLs were lost. The loss of income was estimated at 3.2 million USD [95%CI 2,1-4,5] en 2016, and 3,3 million USD [95%CI 2,3-4,4] in 2017. This represents the highest financial loss from rabies, followed by the cost of postexposure prophylaxis (PEP) of 86’848 $USD and 89’371 $ USD respectively. From the whole cost of rabies in Mali, 92% of the cost in 2016 and 94% of those in 2017 were attributable to premature mortality and the cost of help seeking. The proportion of cost of PEP was 3% in 2016 and 2017 of the total cost of disease. The cost related to dog vaccination changed from 3% to 1% in the same time period. Conclusion This study shows that despite the possibility of preventing human rabies by PEP, its burden remains important in Malian communities. Rabies control by mass vaccination of dogs is hardly done and access to PEP is difficult. However, Rabies elimination by mass vaccination of dogs has been demonstrated to be feasible. Hence a coordinated regional effort between countries by funding dog mass vaccination and full access to PEP can eliminate rabies in West Africa.

In the framework of the research network on integrated control of zoonoses in Africa (ICONZ) a dog rabies mass vaccination campaign was carried out in two communes of Bamako (Mali) in September 2014. A mixed method approach, combining quantitative and qualitative tools, was developed to evaluate the effectiveness of the intervention towards optimization for future scale-up. Actions to control rabies occur on one level in households when individuals take the decision to vaccinate their dogs. However, control also depends on provision of vaccination services and community participation at the intermediate level of social resilience. Mixed methods seem necessary as the problem-driven transdisciplinary project includes epidemiological components in addition to social dynamics and cultural, political and institutional issues. Adapting earlier effectiveness models for health intervention to rabies control, we propose a mixed method assessment of individual effectiveness parameters like availability, affordability, accessibility, adequacy or acceptability. Triangulation of quantitative methods (household survey, empirical coverage estimation and spatial analysis) with qualitative findings (participant observation, focus group discussions) facilitate a better understanding of the weight of each effectiveness determinant, and the underlying reasons embedded in the local understandings, cultural practices, and social and political realities of the setting. Using this method, a final effectiveness of 33% for commune Five and 28% for commune Six was estimated, with vaccination coverage of 27% and 20%, respectively. Availability was identified as the most sensitive effectiveness parameter, attributed to lack of information about the campaign. We propose a mixed methods approach to optimize intervention design, using an “intervention effectiveness optimization cycle” with the aim of maximizing effectiveness. Empirical vaccination coverage estimation is compared to the effectiveness model with its determinants. In addition, qualitative data provide an explanatory framework for deeper insight, validation and interpretation of results which should improve the intervention design while involving all stakeholders and increasing community participation. This work contributes vital information for the optimization and scale-up of future vaccination campaigns in Bamako, Mali. The proposed mixed method, although incompletely applied in this case study, should be applicable to similar rabies interventions targeting elimination in other settings.

Rabies is a neglected but preventable zoonotic disease that predominantly affects the most vulnerable populations living in remote rural areas of resource-limited countries. To date, every country on the African mainland is considered endemic for dog-mediated rabies with an estimated 21'500 human rabies deaths occurring each year. In 2018, the United Against Rabies collaboration launched the Global Strategic Plan to end human deaths from dog-mediated rabies by 2030. The epidemiology of rabies from most Western and Central African countries remains poorly defined, making it difficult to assess the overall rabies situation and progress towards the 2030 goal. In this review, we attempt to provide an overview of the current rabies situation in 22 West and Central African countries based on published scientific literature and information obtained from rabies focal points. To this end, information was collected on i) established surveillance, ii) diagnostic capacity, iii) post-exposure prophylaxis (PEP) availability and coverage, iv) dog population estimates, v) dog vaccination campaigns, vi) animal and human health communication (One Health), vii) molecular studies, viii) Knowledge, Attitude and Practices (KAP), ix) cost estimates and x) national control strategies. Although rabies is a notifiable disease in the majority of the studied countries, national surveillance systems do not adequately capture the disease. A general lack of rabies diagnostic capacity has an additional negative impact on rabies surveillance and attempts to estimate rabies burden. Recurrent shortages of human rabies vaccine are reported by all of the countries, with vaccine availability usually limited to major urban centers but no country has yet adopted the new WHO-recommended 1-week intradermal vaccination regimen. Most countries carry out subsidized mass dog vaccination campaigns on World Rabies Day. Such activities are indispensable to keep rabies in the public consciousness but are not of the scale and intensity that is required to eliminate rabies from the dog population. Countries will need to scale up the intensity of their campaigns, if they are to progress towards the 2030 goal. But more than half of the countries do not yet have reliable figures on their dog populations. Only two countries reached stage 2 on the Stepwise Approach towards Rabies Elimination ladder - indicating that their national governments have truly prioritized rabies elimination and are thus providing the necessary support and political buy-in required to achieve success. In summary, the sub-region of West and Central Africa seems to be divided into countries which have accepted the challenge to eliminate rabies with governments committed to pushing forward rabies elimination, while other countries have achieved some progress, but elimination efforts remain stuck due to lacking government commitment and financial constraints. The possibility to meet the 2030 goal without international solidarity is low, because more than two-thirds of the countries rank in the low human development group (HDI ≤ 152). Leading countries should act as role models, sharing their experiences and capacities so that no country is left behind. Unified and with international support it is possible to reach the common goal of zero human rabies deaths by 2030.

Rabies is endemic in Côte d'Ivoire and was identified in January 2017 as a priority zoonosis by all stakeholders in public health. A well-designed integrated national rabies control is essential to attain the objective of zero human deaths from dog rabies by 2030. The current study describes the complementary elements of dog bite risk factors and the dog population estimate that are relevant for planning sustainable interventions. We conducted a transverse survey in 8'004 households in the departments of San Pedro (4'002) and Bouaké (4'002), covering both rural and urban areas. The dog-household ratio was estimated at one dog for three households (0.33) or one dog for 20 people (0.05). The owned canine population on a national level was estimated at 1'400'654 dogs (range 1'276'331 to 1'535'681). The main dog bite risk factors were dog ownership, being male, and living in urban San Pedro Department. The results lay a foundation for public engagement and further steps for mass vaccination of the household dog population to reach vaccination coverage of at least 80%. Stakeholders further recommend raising awareness of dog owners, reinforcing knowledge in school children and young boys, and behavior changes towards domestic animals.

Rabies affects more than 150 countries worldwide. Cote d'Ivoire is one of the rabies-endemic countries that has recorded deaths every year since 2006. The evolution of these deaths is almost constant with an average of 18 annual deaths (annual incidence = 0.06-0.08 per 100,000). Children predominate among these victims. However, prevention measures exist in anti-rabies centers distributed throughout the country. The objective of this study was to determine the factors related to rabies risk in Cote d'Ivoire through Gavi rabies project entitled ‘Impact of rabies and immunization in Central and West Africa’. The implementation was conducted from 2016 to 2018 in two departments of Cote d'Ivoire (Bouake and San Pedro). The study population was dog-bite victims vaccinated in anti-rabies centers of project sites from January to December 2016. Two non-free rabies immunization protocols are used in the country (Essen and Zagreb). Information was collected from bites victims for an adequate follow-up. It was to apprciate the risk of developing rabies through access to care, the immunization status of biting animal, the category of exposure and the result of rabies post exposure prophylaxis (compliance). Local program implementers responsible for these bite-management activities and veterinary staff had receved training and the necessary material. The public health education and information dissemination activities were carried out in support of promoting a wide spread of rabies prevention messages. Household surveys were conducted by sociology students in 4002 households each in urban and in rural areas. This activity helped to find people exposed by dogs and who did not receive any Post Exposure Prophylaxis (PEP). The study registered 1,263 bite victims in pilot anti-rabies centers in 2016, 51% of them were children. People living in urban areas were strongly represented (87%) because of anti-rabies centers proximity. Dog was the most animal associated to exposure (94%). Seventy-two percent (72%) of them had owners, but only 14% were vaccinated against rabies. More than half of dog bite victims had category III of exposure (58%). PEP compliance record was very low (37%), which means that 63% of bite victims have not completed the protocol. This study conducted in Bouake and San Pedro showed somes factors responsible for rabies deaths evolution in Cote d'Ivoire. Main issues identified are the geographical accessibility of anti-rabies centers, frequent bites caused by unvaccinated dogs, often category III of exposure and many non-completions of rabies PEP in ignorance context. The establishment of national comprehensive and integrated rabies control program is needed in Cote d'Ivoire. It must take into account all these factors by focusing on public awareness, dog vaccination and adoption of modern intradermal vaccination regimens to better manage rabies situation in Cote d'Ivoire.

Rabies is a public health problem in the world especially in Côte d'Ivoire. The epidemiological surveillance of rabies revealed 10,197 exposures with 17 deaths in 2015 and 11,481 exposures with 18 deaths in 2016. The management of exposed people was based on WHO's intramuscular (IM) protocols (Essen and Zagreb). The usual results from these anti-rabies protocols showed low compliance corresponding to 45-50% exposed people who did not complete the Post Exposure Prophylaxis (PEP) schedule,mainly due to the cost of vaccines. The main objective of the project was to test the feasibility of a free rabies PEP based on the Thai Red Cross (TRC) protocol used by intradermal route. The study population was exposed people (patients) vaccinated in the anti-rabies center of Bouake and San Pédro which were two departments selected for this study. The TRC protocol was implemented in y ear 2017. Patients have been vaccinated according to IM post exposure protocols or by the TRC schedule.This new protocol was administered free of charge to exposed people with their consent. Patients who did not complete the PEP schedule were researched and interviewed for having the reasons related to this non-completion. In 2017, 1625 exposures were registered including 1121 in Bouaké and 504 in San Pedro. Overall immunization compliance was 63%. Patients who received the TRC schedule were 829 (52%)With 70% PEP compliance The PEP compliance of Zagreb protocol was 67%%and the Essen protocol recorded 38% of PEP compliance. The research of exposed people who did not complete the PEP schedule has shown that cost effectively remains the major limiting factor among exposed people vaccinated by Essen or Zagreb protocols. But negligencewas main cause for the non-completion PEP among exposed people who accepted the TRC schedule. Introduction of free rabies PEP through the TRC protocol has found the population support. This experience has been successful with a better PEP compliance, which means safe protection of people from rabies.This study has demonstrate that free rabies vaccine used by ID route is one of the best solutions to improve the PEP compliance in Côte d'Ivoire.Nevertheless, alternatives ways should be provided in order to minimize vaccine wastage rates in anti-rabies center receiving very few exposed persons.Community engagementwould be necessary for more rabies awareness raising and improving bite victim's follow-up.

Context Rabies is endemic in Mali, but little is known about the distribution of rabies and its surveillance across the country. Documenting the evolution of rabies and the problems related to surveillance is useful to facilitate elimination of human rabies by 2030. Method Data collected at the Central Veterinary Laboratory (LCV) from 1999 to 2017 and through the surveillance system functioning at household, health and veterinary structure levels, as established by the Global Vaccine Alliance funded project on the burden of rabies, between 2016 and 2017 in Bamako and the Sikasso region were used in this study. All data on animals examined for rabies by the direct fluorescence antibody test (DFA) during the specified time period were summarized, and the proportion of rabies positive tested among animals suspected of rabies was estimated. From the number of dogs tested positive for rabies, a cumulative incidence was estimated for the total canine population. The number of positive tested samples was divided by the product of the estimated canine population and number of years (18). In addition, the number of human rabies cases was analyzed to estimate a cumulative incidence. Results Among all animal samples suspected for rabies, 93.2% [95% CI 90.6–95.3] were positive by the DFA test. From the 486 included animal samples, 94.7% [95% CI 92.3–96.5] were domestic dogs with 90.9% [95% CI 87.9–93.3] positive, which stands out as the main reservoir of rabies in Mali. Cats, cattle, sheep and donkeys also tested positive using the DFA test. The cumulative incidence of canine rabies was estimated at 0.371 [95% CI: 0.336–0.408] / 10′000 dogs. The highest incidence was observed in Bamako, the capital of Mali, with a cumulative incidence of 2.242 [95% CI: 2.001–2.504] / 10′000 dogs, followed by Koulikoro with 0.335 [95% CI: 0.258–0.429] / 10′000 dogs. For other areas far from LCV, the cumulative incidence was low, with zero in Kidal. Nationally reported cases of human rabies declined in recent years with an average of 12.6 [95% CI: 8.7–16.5] deaths per year. This result gives an annual incidence of 0.1047 [0.0742–0.1352] / 100′000 inhabitants. Conclusion Over the past 18 years, rabies is endemically stable in Mali despite the decrease in reported human cases. The disparity among regions in number of samples tested indicates a low level of clinical and laboratory surveillance and likely a high level of underreporting. Dogs play the main role in rabies transmission in Mali. Monitoring of and decisions for post-exposure prophylaxis (PEP) includes other animals (cats, cattle, and monkeys) involved in transmission. Mali should develop a national rabies strategy to include better communication between the public health and animal health sectors, strengthening of laboratory surveillance capacity, mass vaccination of dogs and guaranteed access to PEP.

Water is an essential element of life, but it can also be a source of disease. Apart from direct consumption of unsafe water, direct contact and indirect consumption puts people at risk of many different types of pathogens. Employing a mixed methods approach, consisting of questionnaires and direct observations, we assessed access to, and use of, different water sources by the participants of the district des Savanes in northern Côte d'Ivoire. The use of water sources was put in relation to the potential risk of acquiring schistosomiasis and fascioliasis. Overall, 489 people aged 8 to 82 years participated. While all participants had access to safe water, 63% were in direct contact with unimproved water and 31% directly consumed unsafe water. More than a third of the people who otherwise reported using only improved water for all activities came in contact with unimproved water through crossing open water when going to their workplace, school or other destinations. Self-reported blood in urine - a marker for Schistosoma haematobium with reasonable sensitivity and specificity - was reported by 6% (n=30), self-reported blood in stool - an unspecific marker for Schistosoma mansoni - was reported by 7% (n=35), while blood co-occurring in both urine and stool was reported by another 10% (n=48) of participants. Accessing unimproved water for any activity (including crossing) was associated with higher odds of reporting blood in urine and/or blood in stool (odds ratio: 1.90; 95% confidence interval: 1.07-3.36). Our results have important rami-fications for intervention programmes targeting neglected tropical diseases, and emphasize the need for a wider supply of safe water to rural populations, since the water supply at the workplace needs to be considered as well next to the water supply at home. Crossing of open water sources is an important risk factor for sustained transmission of schistosomiasis.

Background Schistosomiasis is one of the neglected tropical diseases endemic to Mali. There has been insufficient investigation of the morbidity burden in highly endemic irrigated rice areas with the ongoing mass drug administration with praziquantel. In February 2005, a year after an initial mass drug administration in 2004, we performed the first cross-sectional survey of schistosomiasis in the Kokry-Bozo village in the Office du Niger rice irrigation region. In the fourteen years since this survey, there has been almost no research into schistosomiasis morbidity in Mali due to lack of funding. Therefore, the 2005 survey supplies near-baseline data for any future research into the treatment impacts in the area. Methods One hundred and ninety-four children aged 6–14 years from two schools were assessed for bladder pathology by ultrasound, and for anaemia and micro-haematuria by laboratory tests. Schistosoma eggs were examined microscopically in fresh stool and urine samples. Multivariate logistic regression analysis quantified the association of Schistosoma infections with anaemia, bladder pathology and micro-haematuria. Akaike’s information criterion was used to test the assumption of linear effects of infection intensity classes and used to compare across models. Results The overall prevalence of schistosomiasis in 189 school children was 97%; 17% (33/189) had a single infection (S. mansoni,13%, or S. haematobium, 4%) and 80% (156/189) were co-infected with S. mansoni and S. haematobium. The overall prevalence of S. mansoni with light infection was 27% (53/194), moderate infection was 24% (47/194) and heavy infection was 42% (81/194). Of the 194 of children investigated for S. haematobium 59% (114/194) had light infection and 26% (50/194) had heavy infection. No hookworm eggs were detected. The level of abnormal bladder pathology was 18% (35/189) with the highest found in 10–14 year old children. The prevalence of anaemia was 91% (172/189) and was twice as likely to be associated (OR 2.0, 95% CI 1.1–3.9) with S. mansoni infections than in children without infection. As infection intensity with S. mansoni increased the risk of anaemia (OR 2.0, 95% CI 1.1–3.9) also increased. As infection intensity with S. haematobium increased bladder pathology (OR 2.4, 95%CI 1.3–4.5), haematuria (OR 6.7, 95%CI 3.3–13.6) and micro-haematuria increased (OR 2.4, 95%CI 1.3–4.5). Conclusion Our research contributes an important micro-geographical assessment of the heavy burden of schistosomiasis and associated morbidity in children who live in the rice irrigation regions. Our literature review found that there has been very limited research conducted on the impact of the treatment to control morbidity in the ON. Therefore, there is a need to do a comparable, but more extensive, study to identify any changes in morbidity and to indicate current requirements for the control programme. Our results from 2005 called for routine integration of iron supplementation, food fortification and diet diversification into the deworming program.

Background Even in the high transmission areas of sub-Saharan Africa (SSA), the incidence of falciparum malaria varies greatly depending on factors such as age, rainfall pattern, distance to breeding places, quality of houses, and existing vector control measures. Insecticide-treated mosquito nets (ITN) have now become the vector control standard in nearly all of SSA. This study aims to describe and analyse the incidence of malaria in a cohort of young children protected with ITN in rural West Africa. Methods Data of a subsample from a large community trial in rural north-western Burkina Faso consisting of 420 children were analysed. The main aim of the trial was to evaluate the long-term effects of ITNs in two groups of new-borns; Group A was protected with ITN from birth onwards while Group B was protected only from month six onwards. The primary objective of this study was to describe malaria incidence in detail with an analysis of the impact of potentially relevant determinants of malaria incidence, in particular age, sex, ITN protection, village, month and season as secondary objective. Bivariate negative binomial regression analysis was used to calculate incidence rate ratios of malaria incidence. Moreover, relevant variables were included in a multivariate negative binomial regression model to examine possible risk factors for malaria. Results Out of the 420 study children 387 (92.1%) developed a total of 1822 falciparum malaria episodes; the malaria incidence rate was 7.6 per 1000 child days. Group A children had lower malaria incidence rates compared to group B, but only in early infancy. Malaria incidence varied significantly between villages and increased with age, but no sex-specific differences were observed; these findings were confirmed in the multi-variate analysis. Malaria incidence peaked sharply towards the end of the rainy season in September but there were no differences in the seasonal pattern by study group. Conclusions The study, carried out in a high-transmission West African area, shows that malaria incidence remains high in spite of maximum ITN coverage.

Malaria blood-stage vaccines are in an early phase of clinical development with MSP1 being a major antigen candidate. There are limited data on the protective efficacy of antibodies against subunits of MSP1 in the malaria endemic areas of sub-Saharan Africa. This prospective cohort study was nested into a large insecticide-treated mosquito net (ITN) trial during which neonates were individually randomised to ITN protection from birth vs. protection from month six onwards in rural Burkina Faso. A sub sample of 120 children from three villages was followed for 10 months with six measurements of MSP1(42) antibodies (ELISA based on recombinant 42kDa fragment) and daily assessment of malaria episodes. Time to the next malaria episode was determined in relation to MSP1(42) antibody titres. MSP1(42) antibody titres were dependent on age, season, ITN-group, number of previous malaria episodes and parasitaemia. There were no significant differences in time until the next malaria episode in children with low compared to children with high MSP1(42) antibody titres at any point in time (101 vs. 97 days in May, p=0.6; 58 vs. 84 days in September, p=0.3; 144 vs. 161 days in March, p=0.5). The findings of this study support the short-lived nature of the humoral immune response in infants of malaria endemic areas. The study provides no evidence for antibodies against a subunit of MSP1 being protective against new malaria episodes in infants.

Large-scale administration of anthelminthic drugs currently is the most widely used intervention for controlling morbidity due to schistosomiasis and soil-transmitted helminthiasis. An important issue is drug efficacy monitoring. However, the optimal time points post-treatment for assessing the efficacy of praziquantel against Schistosoma mansoni and albendazole against hookworm infections are not known. Forty-nine schoolchildren infected with S. mansoni and 52 infected with hookworm were treated with a single oral dose of praziquantel (40 mg/kg) and albendazole (400 mg), respectively. Stool samples were collected on 19 occasions over a 44-day post-treatment follow-up period, and two Kato-Katz thick smears per sample were examined at each time point. Both the mean egg counts and observed cure rates varied depending on the time point post-treatment. The highest reduction in the geometric mean egg counts (>97%) and the highest observed cure rate (>97%) of S. mansoni infections were found 15-20 days after praziquantel administration. Among the hookworm-infected children, egg counts decreased rapidly within the first week after albendazole administration (>95%), whereas infection rates showed high and heterogeneous (45.0-71.2%) levels at later time points. Both praziquantel and albendazole were highly efficacious in reducing the overall egg burden of S. mansoni and hookworm, respectively. We suggest that 15-20 days post-treatment is the most appropriate time point for efficacy evaluation of praziquantel against S. mansoni. Although no clear conclusion can be drawn for the optimal timing of efficacy evaluation of albendazole against hookworm, a 2-3-week time frame seems a reasonable compromise. This is justified on logistical grounds (i.e. collection of stool samples only once) and growing emphasis on integrating the control of schistosomiasis and soil-transmitted helminthiasis, including drug efficacy monitoring.

We aimed at characterizing commercial and traditional village poultry farming in Mali, with a focus on practices influencing the risk of transmission of avian influenza and Newcastle disease. Surveys were conducted in 2009–2011 in a study area covering approximately 98% of the Malian poultry population. Among the 282 commercial farms investigated, of which 64 had not been known by the government authorities, 83% were located within a 50 km radius from the capitals of the country and regions and 54% had low biosecurity standard. Among the 152 randomly selected village household flocks investigated, characteristics were overall similar to those in other African countries but some differences were notable including a large flock size (median 44 poultry), a low presence of ducks and geese (11% and 1.1% of flocks, respectively), vaccination against Newcastle disease being common (49% of flocks), a low proportion of households selling sick and dead birds (0.7% and 0%, respectively) and limited cohabitation between poultry and humans at night. Our recommendations to limit the risk of disease transmission include (1) for commercial farms, to introduce compulsory farm registration and accreditation, to increase technical proficiency and access to credit for farms with low biosecurity, and to support poultry producer associations; (2) for village poultry, to promote better quarantine and management of sick and dead birds. Such detailed knowledge of country-specific characteristics of poultry production systems is essential to be able to develop more efficient disease risk management policies.

Ivermectin (Mectizan MK-933) is an efficient microfilaricidal drug used for mass treatment by the Onchocerciasis Control Programme (OCP) in the savanna zones of West Africa. Some populations of the forest zone of Côte d'Ivoire have very high microfilarial loads, so it was decided to treat some of these populations with ivermectin, in order to avoid an eventual reinfestation of the protected savanna areas. A pilot campaign was carried out in a small stream catchment area where onchocerciasis transmission is usually high. The whole population was treated orally with ivermectin (200 micrograms/kg of body weight), with the exception of children under 5 years of age, pregnant women and people who were ill. The results showed a very high efficiency of ivermectin in the treatment of onchocerciasis in the forest zone. The prevalence rate of microfilaria dropped from 60.1 to 33.2%. The community microfilarial load was reduced from 29.7 to 5.6 microfilariae per skin snip. To maintain this effect, the authors recommend regular treatment of all new comers into the area.The microfilaricidal drug, ivermectin, is used by the Onchocerciasis Control Program for mass treatment in West Africa's savanna zones. To avoid reinfestation of these protected savanna areas, ivermectin treatment has been proposed in selected forest zones of the Ivory Coast with high microfilarial loads. A pilot project was carried out in a small stream catchment area with extremely high onchocerciasis transmission. With the exception of children under 5 years of age, pregnant women, and those who were ill, the entire population of this area (n = 1553) was treated orally with ivermectin (200 mcg/kg of body weight). The prevalence rate of microfilariae dropped from 60.1% before treatment to 33.2% at 6 months after treatment. The community microfilarial load was reduced from 29.7 to 5.6 microfilariae/skin strip. Thus, the level of endemicity changed from hyper- to hypoendemic as a result of treatment. In order to maintain hypoendemicity, regular ivermectin treatment of all newcomers to the study area is recommended.

A simple inexpensive trap (Esperanza window trap) was shown recently to collect significant numbers of Simulium ochraceum sensu lato, a major vector of Onchocerca volvulus in Mesoamerica. Here, we report studies optimizing this trap for the collection of Simulium damnosum s.l., the major vector of O. volvulus in Africa. A shortened, blue and black striped version of the Esperanza window trap, when baited with a combination of CO2 and worn trousers, rivalled human landing collections in the number of S. damnosum s.l. females collected. Traps baited with a commercially available human skin lure and CO2 resulted in collections that were not significantly different than those obtained from traps baited with worn trousers and CO2. This suggests that the Esperanza window trap may offer a replacement for human landing collections for monitoring onchocerciasis transmission in Africa.

The aim of the present study was to contribute to define urinary schistosomiasis-related morbidity indicators and to understand the relationship between infection intensity and disease burden among school-aged children in different endemic areas of Mali. A cross sectional study was undertaken in two different endemic settings: Koulikoro district, along the river and Selingue dam area in the Niger River Basin in order to compare and describe morbidity related to Schistosoma haematobium infection. A total of 667 children aged 7-14 were enrolled in the study. Among these, 333 were from Koulikoro district (175 boys and 158 girls) and 334 from Selingue dam area (169 boys and 165 girls). The overall prevalence of S. haematobium in the two areas was 91.5%; Koulikoro (97.0%) and Selingue (85.9%) and this difference was significant after adjusting for age, sex and clustering within villages. Prevalence of heavy infection (≥ 50 eggs per 10 ml of urine), 57.6% in Koulikoro and 43.8% in Selingue, did not differ significantly after adjusting for age, sex and clustering within villages. The transmission of Schistosoma mansoni was mainly confined to Selingue dam area (12.5%) and was nearly absent in Koulikoro district (1.1%). Blood in urine was the most frequently reported clinical symptom, more common in Koulikoro (76.8%) than in Selingue (57.6%). In a multivariable logistic regression model adjusting for sex, age group, egg intensity category and clustering within villages, Selingue had higher prevalence of macro-haematuria, urinary tract pathology, upper urinary tract pathology and total pathology than Koulikoro, while micro-haematuria did not differ between the two areas. Morbidity measures increased to some extent with egg intensity category, especially micro-haematuria. The results obtained from this study are of importance for planning intervention as for monitoring and evaluation of control in different endemic settings in Mali.

Rice is becoming increasingly important as a staple food in West Africa and there is a need to increase production to meet the demand and one way to achieve this is to harvest two annual crops. It is possible that such intensified irrigation could affect transmission of schistosomes and this study attempts to compare schistosome transmission in single and double-cropped areas of an irrigation scheme, 'Office du Niger', in Mali. Double cropping has been practised for some years in the Niono area while in the Kolongotomo area still only a single crop is grown. Parasitological surveys conducted in 10 villages (5 from each of these 2 areas) showed that Schistosoma haematobium was less prevalent in the area with single cropping than in the area with double cropping. In order to compare transmission patterns between the two areas, all human-water contact sites around four villages (two from each area) were identified and included in transmission studies. From August 1996 to June 1997, eight surveys were conducted, at intervals of approximately 45 days, in each of these sites to record density of the intermediate hosts, density of infected snails, environmental factors (especially density of aquatic macrophytes), and frequency of human-water contacts. Although the data provide useful information on transmission patterns in Niono and Kolongotomo areas, they fail to demonstrate clear-cut differences in snail population dynamics and transmission patterns between the two areas. A key element in snail habitats in both areas is the abundance of aquatic macrophytes, especially the submerged species. Snail control using environmental modification should focus on controlling these plants in human-water contact sites.