Our findings suggest a complex RVFV epidemiological cycle in the Union of Comoros with probable inter-islands differences in RVFV blood circulation patterns. end of the follow-up. We found an estimated RVFV antibody prevalence of 19.3% (95% CI: [15.6%23.0%]). Our findings suggest a complex RVFV epidemiological cycle in the Union of Comoros with probable inter-islands differences in RVFV blood circulation patterns. Moheli, and potentially Anjouan, appear to be acting as endemic reservoir of contamination whereas RVFV persistence in Grande Comore could be correlated with trade in live animals with the eastern coast of Africa. More data are needed to estimate the real impact of the Ivacaftor benzenesulfonate disease on human health and on the national economy. == Author Summary == Rift Valley fever (RVF) is usually a viral disease transmitted by mosquitoes to ruminants. The disease may impact humans and has a great impact on the economy of the affected country. RVF occurs mostly in African countries, but epidemics have been reported in Madagascar and in the Arabian Peninsula. In the Union of Comoros, Ivacaftor benzenesulfonate RVF computer virus (RVFV) has been suspected of constantly circulating since 2009 without any notifications of the typical clinical signs by the Comorian Animal Health Services. From April 2010 to August 2011, we conducted a livestock longitudinal survey in Grande Comore, Moheli and Anjouan. Our study aimed to detect RVFV-specific antibody acquisitions in cattle and goats. Simultaneously, a longitudinal entomological survey was conducted to describe the diversity of mosquitoes in the study zones and ruminant trade-related information was collected. Our investigations showed that Comoros ruminants acquired RVFV-specific antibodies all along the year and particularly in Moheli during the dry season. Our findings suggest a complex RVFV epidemiological cycle in the Union of Comoros with probable inter-islands differences in RVFV blood circulation patterns. The disease appears to be endemic in Moheli and potentially Anjouan, but the persistence of the disease in Grande Comore could be correlated with trade in live animals with the eastern coast of Africa. == Introduction == Rift Valley fever (RVF) is an arthropod-borne zoonotic disease caused by a RVF computer virus (RVFV), a member of thePhlebovirusgenus of the family Bunyaviridae[1]. RVFV causes significant morbidity and mortality among sheep, goats, cattle and also affects humans. In livestock, abortion storms and high mortality observed among the younger animals cause significant economic losses[2],[3]. Humans are usually infected by contact with infectious animal tissues through inhalation or aerosols generated by Ivacaftor benzenesulfonate slaughtering and necropsy[4]. Arthropod vectors play an important role during the onset of epidemic and inter-epidemic periods[5]. In endemic areas, RVFV is usually maintained in the environment through an enzootic vertebrate-arthropod cycle[6]. RVFV has been isolated from many vectors in the field[7], such as ticks and sand flies which are able to transmit the computer virus in experimental conditions[8],[9]. However, mosquitoes are the main insects involved in the spread of RVFV during epidemics. RVFV has been isolated from at least 40 species of mosquitoes belonging to 8 genera but only some of them are Rabbit polyclonal to ALX3 susceptible and able to transmit RVFV under laboratory conditions[10]. RVF is usually widely present in Africa and has been distributing to Madagascar and the Arabian Peninsula[11],[12]. In 2007, RVF outbreaks were reported in several eastern and southern African countries[13]. A few weeks later, and for the first time, RVFV was detected in the Comoros archipelago following the hospitalization of a young Grande Comorian.