Seroprevalence, geographical distribution, and risk factors of peste des petits ruminants in the Republic of Chad.

OBJECTIVE: The objective of this study was to determine the prevalence, geographical distribution, and main risk factors for peste des petits ruminants (PPR) in the Republic of Chad. MATERIALS AND METHODS: A total of 3,546 sera collected from unvaccinated small ruminants including 1,699 goats and 1,847 sheep in 19 of the 23 regions in Chad were randomly sampled. The competitive enzyme-linked immunosorbent assay technics were used for serological analysis. RESULTS: The overall seroprevalence at the individual level was 52.9%±1.6% (48.9% for goats and 56.2% for sheep). Seroprevalence observed in the Chari Baguirmi, Ouaddaï, and N'Djamena regions was significantly higher than those in the other regions. Transhumant herds are the most exposed than the sedentary ones. Older animals were more affected than the young ones. Kababich sheep are the most affected than other breeds. CONCLUSION: This study has shown that the PPR virus is circulating in the Republic of Chad. In view of the results obtained, the disease is enzootic in the country. Epidemiological information obtained including seroprevalence rate, risk factors (sex, breed, age, and mode of rearing), and geographical distribution will help to define an appropriate strategy for PPR control in the Republic of Chad.

Cost Description and Comparative Cost Efficiency of Post-Exposure Prophylaxis and Canine Mass Vaccination against Rabies in N'Djamena, Chad.

Rabies claims approximately 59,000 human lives annually and is a potential risk to 3.3 billion people in over 100 countries worldwide. Despite being fatal in almost 100% of cases, human rabies can be prevented by vaccinating dogs, the most common vector, and the timely administration of post-exposure prophylaxis (PEP) to exposed victims. For the control and prevention of human rabies in N'Djamena, the capital city of Chad, a free mass vaccination campaign for dogs was organized in 2012 and 2013. The campaigns were monitored by parallel studies on the incidence of canine rabies based on diagnostic testing of suspect animals and the incidence of human bite exposure recorded at selected health facilities. Based on the cost description of the campaign and the need for PEP registered in health centers, three cost scenarios were compared: cumulative cost-efficiency of (1) PEP alone, (2) dog mass vaccination and PEP, (3) dog mass vaccination, PEP, and maximal communication between human health and veterinary workers (One Health communication). Assuming ideal One Health communication, the cumulative prospective cost of dog vaccination and PEP break even with the cumulative prospective cost of PEP alone in the 10th year from the start of the calculation (2012). The cost efficiency expressed in cost per human exposure averted is much higher with canine vaccination and One Health communication than with PEP alone. As shown in other studies, our cost-effectiveness analysis highlights that canine vaccination is financially the best option for animal rabies control and rabies prevention in humans. This study also provides evidence of the beneficial effect of One Health communication. Only with close communication between the human and animal health sectors will the decrease in animal rabies incidence be translated into a decline for PEP. An efficiently applied One Health concept would largely reduce the cost of PEP in resource poor countries and should be implemented for zoonosis control in general.

Wildlife and pastoral society--shifting paradigms in disease control.

The dramatic changes in the human and animal populations in Africa over the last century demand the re-examination of priorities and policies. The introduction of developed medical and other human technologies into the continent has contributed to increases in population and a rapid, unsustainable increase in the utilization of resources. This in turn has led to the destruction of flora and fauna on an unprecedented scale with little real improvement in the human condition. One factor in this has been the increase in livestock in line with human demographic growth, as it is a traditional livelihood of many African peoples. In recent years the growth in livestock populations has slowed owing to a cycle of degradation and disease, affecting especially traditional pastoral systems with a close physical association between people, livestock, and wild animals. Pathogens benefit hugely from the dynamic state created by animal migration, although to some extent the livestock and certainly wildlife show considerable tolerance to this. One of the grave economic consequences of this increase in disease has been collapse of the export trade. In order for Africa to fully benefit and share in world trade, the zoosanitary situation must show improvement. To do this without destroying the natural resource base and traditional pastoral systems, will require a careful, future-oriented land-use policy along ecologically sound criteria. Export livestock will have to be maintained in areas, probably free of ruminant wildlife, with strict veterinary controls. If this can be balanced with sufficient areas retained for traditional pastoralism and wildlife, with perhaps the main income from recreational tourism and local consumption, the benefits will be considerable. The answer may be community-based, low-cost, decentralized health systems for pastoral communities, with less stringent sanitary mandates, a private/parastatal sector servicing, with specialization in wildlife, dairy or export livestock and a central veterinary policy, related to surveillance and monitoring using small well-resourced professional teams to carry out regulatory and statutory duties.