Preventive Veterinary Medicine 102 (2011) 167–174 Contents lists available at ScienceDirect Preventive Veterinary Medicine j ourna l ho me pag e: ww w.elsevi er.com/locate/prev etmed Cartographical analysis of African swine fever outbreaks in the territory of the Russian Federation and computer modeling of the basic reproduction ratio V.M. Gulenkin, F.I. Korennoy ∗ , A.K. Karaulov, S.A. Dudnikov FGBI “Federal Centre of Animal Health” (FGBI “ARRIAH”), mkr.Yurevets, Vladimir 600901, Russian Federation a r t i c l e i n f o Keywords: African swine fever Geographical information system Basic reproduction ratio Modeling Risk factors a b s t r a c t African swine fever (ASF), have been introduced into the Russian Federation from Tran- scaucasia countries, has spread widely across the territory of the southern region of Russia since 2008. In this work we present an analysis of the spatial and temporal spread of the dis- ease, determine risk factors by means of GIS tools and model the dynamics of the epidemic process both within infected premises (farms) and at the between-farm level to estimate the basic reproduction ratio R 0 . The analysis allowed us to make a conclusion about the anthropogenic nature of the risk factors for disease spread. The major significant risk fac- tors identified were: density of the road network, density of domestic swine population and density of water bodies in the study area. The basic reproduction ratio was estimated to range from 2 to 3 at the between-farm level and from 8 to 11 within the infected farms. These initial studies of the ASF epidemic provide information on which to based control and prevention programs. © 2011 Elsevier B.V. All rights reserved. 1. Introduction One of the main and most important parameters neces- sary for successful modeling and prediction of infectious disease spread is the basic reproduction ratio, R 0 . This parameter is used to predict the speed and scale of dis- ease spread and the level of herd immunity required to control the disease. The basic reproduction ratio is defined as the average number of secondary infections caused by introducing one infected individual (animal) into the population, which consists exclusively of susceptible hosts (Anderson and May, 1992). In this current study we have attempted to estimate the value of R 0 at both the between-farm and within-farm level using a simple Susceptible-Exposed-Infectious-Resistant (SEIR) type epi- demic model. ∗ Corresponding author. Tel.: +7 4922 37 22 54. E-mail address: korennoy@arriah.ru (F.I. Korennoy). ASF is a highly contagious disease of domestic and wild pigs, characterized by almost 100% mortality and can cause great damage to agriculture and the economy in general. The cause of ASF is a unique DNA virus which is the only member of the Asfarviridae family, genus Asfivirus. No vac- cine exists against ASF and the only acceptable eradication strategy is total depopulation of pigs within the infected farm and also within the surrounding zone of risk. ASF is considered an endemic disease in most southern and eastern African countries, where the virus is maintained either in an ancient sylvatic cycle between warthogs and ticks of the Ornithodoros moubata complex or in a domestic cycle that involves pigs of local breeds, with or without tick involvement (FAO, 2009a,b). Since 1957 a number of outbreaks of ASF have been reported in Spain, Portugal, Cuba, Brazil and some other European and Central American countries. According to official OIE data, the primary outbreaks of ASF in the Cauca- sus region were reported in April 2007 from Georgia. Then the disease apparently spread to other parts of the country, 0167-5877/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.prevetmed.2011.07.004