International Journal of Virology and Molecular Biology 2016, 5(1): 16-26 DOI: 10.5923/j.ijvmb.20160501.03 Comparative Sequence Analysis of Different Strains of African Swine Fever Virus Outer Proteins Encoding Genes from Nigeria, 2009 – 2014 Pam D. Luka 1,2,* , Joseph Erume 2 , Frank N. Mwiine 2 , David Shamaki 3 , Bitrus Yakubu 1 1 Biotechnology Division, National Veterinary Research Institute, Vom, Nigeria 2 College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda 3 Directorate of Research, National Veterinary Research Institute, Vom, Nigeria Abstract African swine fever (ASF) is an economically important disease of domestic pigs causing a huge amount of losses. Understanding the extent and dynamics of genetic diversity of genes coating outer proteins is required for a rational vaccine design and interpretation of efficacy of vaccine or therapy for the control of ASF. This study was designed to investigate the nucleotide structure of genes: E183L, KP177R and O61R encoding outer proteins p54, p22 and p12, respectively, of African swine fever virus isolates from Nigeria for genetic variability. The samples were collected over three years and analyzed for relatedness using MEGA5 and Hopp and Woods procedure for predicting protein antigenic determinants. The result of our comparative study revealed variability in p12 sequences of the isolates collected from different locations within the country. The p54 and p22 genes were observed to be more conserved among the isolates. Hydropathy analysis of all the genes failed to reveal any structural variability within the proteins of interest. Our study revealed mutations (insertions/deletions) within the 3’ terminus of the p12 gene thus we conclude that p12 is under selection pressure and therefore, its utility needs to be further assessed widely for genetic diversity, antigenicity and pathogenicity of the virus. Keywords African swine fever virus, p54 gene, p22 gene, p12 gene, Comparative sequence analysis, Hydropathy profile, Nigeria 1. Introduction African swine fever (ASF) is an economically significant disease of pigs caused by a large DNA virus and a sole member of the family Asfarviridae and genus Asfivirus 1 [1]. African swine fever virus (ASFV) within an infected host, replicates in the cytoplasm with variable levels of virulence that ranges from highly lethal to subclinical infections. The virus within an infected host elicits a peculiar immune response in which no neutralizing antibodies produced are effective and apparently healthy animals become carriers [2]. Both domestic and wild pigs are susceptible to the virus with the soft tick (Ornithodoros genus) being the primary reservoir. Wild African suids such as warthogs and bush pigs have been reported to be infected but hitherto remained clinically asymptomatic. The ASF virion is ~200 nm in diameter and contains more than 50 proteins and consists of several concentric * Corresponding author: pamluka08@gmail.com (Pam D. Luka) Published online at http://journal.sapub.org/ijvmb Copyright © 2016 Scientific & Academic Publishing. All Rights Reserved layers enclosing an electron-dense nucleoid, containing a double stranded DNA genome of 170-190 kilobase pairs (kbp). The viral core is enwrapped by an inner lipid envelope beneath the icosahedral capsid [3]. The extracellular particles also possess an additional envelope which is derived from the plasma membrane. However, on analysis of cell extracts at various life cycle phases of the virus revealed more than 100 viral proteins [4]. ASF has been reported in most sub-Saharan Africa where the virus is maintained within a sylvatic cycle that involves soft tick (Ornithodoros genus) infecting wild pigs with asymptomatic effects. The virus then replicates in the tick before being transmitted to wild swine through blood meal and the cycle maintained indefinitely. Interestingly, these has facilitated the persistence and emergence of new variants in east, central and southern Africa. However, a domestic cycle with or without the involvement of ticks also occur and common in West Africa [5]. The eponymous disease was first described in Kenya 1921 and later thought to be native to the African continent. However, from the first report in 1920s, the virus made an inroad into Europe with devastating effects in Spain, France and Belgium in 1957 and 1960s before being eradicated [6].