Survey of investigation around cases of Rift Valley Fever at Tagant, Mauritania

Background. - Rift Valley Fever (RVF) is a zoonotic arbovirosis. Among animals, it mainly affects ruminants, causing abortions in gravid females and deaths among young animals. In humans, RVF virus infection is usually asymptomatic or characterized by a moderate fever. However, in 1-3% of cases, the disease progresses to a severe form with 50% mortality. Objective. - Search for risk factors and to propose appropriate measures to prevent the potential for extension of the epidemic, and to make recommendations for disease monitoring and control. Methods. - This investigation involved human RVF cases reported between October 12 and November 20, 2012 in the area of Tagant in Mauritania. Arbovirosis diagnosis was established by the laboratory of the National Institute of Public Health Research in Nouakchott (Mauritania) in collaboration with the Pasteur Institute of Dakar (Senegal). Results. - Of 212 subjects, RVF serology was positive in 26 (12%). Among those seropositive for RVF, 11 (42%) had severe hemorrhagic forms. The case fatality rate was 91%. A series of animal abortions (cattle, sheep and goats) was observed in the area where all but two subjects resided. Exposure to potential risk factors for RVF virus infection was found in all patients. Conclusion. - Mortality is very high in the hemorrhagic forms of RVF. Disease prevention is necessary by strengthening the fight against vectors, avoiding contact and consumption of organic products from diseased animals and vaccination of animals in areas where the disease is endemic. Furthermore, it is essential to establish management procedures for patients infected with the RVF virus. An appropriately equipped referral hospital is necessary, together with strengthened epidemiological surveillance by notifying all suspected cases of hemorrhagic fevers. (C) 2015 Elsevier Masson SAS. All rights reserved.