title: Detection of rift valley Fever virus interepidemic activity in some hotspot areas of kenya by sentinel animal surveillance, 2009-2012.
abstract: Rift Valley fever virus causes an important zoonotic disease of humans and small ruminants in Eastern Africa and is spread primarily by a mosquito vector. In this region, it occurs as epizootics that typically occur at 5-15-year intervals associated with unusual rainfall events. It has hitherto been known that the virus is maintained between outbreaks in dormant eggs of the mosquito vector and this has formed the basis of understanding of the epidemiology and control strategies of the disease. We show here that seroconversion and sporadic acute disease do occur during the interepidemic periods (IEPs) in the absence of reported cases in livestock or humans. The finding indicates that previously undetected low-level virus transmission during the IEPs does occur and that epizootics may also be due to periodic expansion of mosquito vectors in the presence of both circulating virus and naïve animals.
authors.affiliation: Ministry of Agriculture Livestock and Fisheries, P.O. Box 00625, Nairobi, Kenya.
authors.forename: Jacqueline Kasiiti
authors.initials: JK
authors.lastname: Lichoti
authors.affiliation: International Livestock Research Institute, P.O. Box 30709-00100, Old Naivasha Road, Nairobi, Kenya.
authors.forename: Absolomon
authors.identifier: 0000-0002-4717-4580
authors.initials: A
authors.lastname: Kihara
authors.affiliation: Kenya Agricultural Research Institute, Biotechnology Centre, P.O. Box 57811-00200, Waiyaki Way, Nairobi, Kenya.
authors.forename: Abuu A
authors.initials: AA
authors.lastname: Oriko
authors.affiliation: Kenya Agricultural Research Institute, Biotechnology Centre, P.O. Box 57811-00200, Waiyaki Way, Nairobi, Kenya.
authors.forename: Leonard Ateya
authors.initials: LA
authors.lastname: Okutoyi
authors.affiliation: International Centre of Insect Physiology and Ecology, Human Health Division, P.O. Box 30772-00100, Nairobi, Kenya.
authors.forename: James Ogaa
authors.initials: JO
authors.lastname: Wauna
authors.affiliation: International Centre of Insect Physiology and Ecology, Human Health Division, P.O. Box 30772-00100, Nairobi, Kenya.
authors.forename: David P
authors.initials: DP
authors.lastname: Tchouassi
authors.affiliation: International Centre of Insect Physiology and Ecology, Human Health Division, P.O. Box 30772-00100, Nairobi, Kenya.
authors.forename: Caroline C
authors.initials: CC
authors.lastname: Tigoi
authors.affiliation: International Livestock Research Institute, P.O. Box 30709-00100, Old Naivasha Road, Nairobi, Kenya.
authors.forename: Steve
authors.initials: S
authors.lastname: Kemp
authors.affiliation: International Centre of Insect Physiology and Ecology, Human Health Division, P.O. Box 30772-00100, Nairobi, Kenya ; Kenya Medical Research Institute, Centre for Virus Research, P.O. Box 54628-00200, Nairobi, Kenya.
authors.forename: Rosemary
authors.initials: R
authors.lastname: Sang
authors.affiliation: Ministry of Agriculture Livestock and Fisheries, P.O. Box 00625, Nairobi, Kenya.
authors.forename: Rees Murithi
authors.initials: RM
authors.lastname: Mbabu