Epidemiological analysis, serological prevalence, and genotypic analysis of foot-and-mouth disease in Nigeria 2008-2009

Authors: EHIZIBOLO, D - National Veterinary Research Institute; PEREZ, ANDRES - University Of California; CARRILLO, CONSUELO - Animal And Plant Health Inspection Service (APHIS); Pauszek, Steven; AL KHAMIS, M - Ahmadu Bello University; AJOGI, I - Ahmadu Bello University; UMOH, J - Ahmadu Bello University; KAZEEM, H - Ahmadu Bello University; EHIZIBOLO, P - Ahmadu Bello University; FABIAN, A - Animal And Plant Health Inspection Service (APHIS); BERNINGER, M - Animal And Plant Health Inspection Service (APHIS); MORAN, K - Animal And Plant Health Inspection Service (APHIS); Rodriguez, Luis; METWALLY, SAMIA - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Transboundary and Emerging Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/2012
Publication Date: 1/24/2013
Citation: Ehizibolo, D.O., Perez, A.M., Carrillo, C., Pauszek, S.J., Al Khamis, M., Ajogi, I., Umoh, J.U., Kazeem, H.M., Ehizibolo, P.O., Fabian, A., Berninger, M., Moran, K., Rodriguez, L.L., Metwally, S.A. 2013. Epidemiological analysis, serological prevalence, and genotypic analysis of foot-and-mouth disease in Nigeria 2008-2009 . Transboundary and Emerging Diseases. 61(6):500-510 DOI:10.1111/tbed.12054.

Interpretive Summary: Foot and mouth disease virus (FMDV) causes a highly contagious and economically devastating disease of cloven-hooved animals that affects the livelihoods of millions of people in some of the poorest regions of the world. Control of FMDV is a challenge due to the large genetic and antigenic variation which has led to the identification of seven FMDV serotypes, referred to as A,O,C, South African Territories (SAT) 1, SAT 2, SAT 3 and Asia 1; and multiple subtypes within each serotype. Each serotype requires a different vaccine to confer protection. Furthermore, little to no cross protection is also observed among subtypes within the same serotype, requiring that each region develops detailed knowledge of circulating strains of virus to find vaccines that are affective against them. Six FMDV serotypes (A, O, C, and the SATs) have been identified in Africa but submissions of FMDV samples to international reference laboratories for characterization are sporadic and knowledge of vaccine coverage for circulating strains is lacking. This study describes the genetic and epidemiological characterization of FMDV serotypes and strains circulating in Nigeria in recent years. Antibodies to five FMDV serotypes, (A, O, SAT1, SAT2 and SAT3) were detected in animals. This is the first report of the presence of FMDV SAT3 in Nigeria. Tissue samples collected from clinical cases in 2008-2009 were positive only for FMDV serotype A indicating that this serotype dominated in this period. This study provides knowledge on the epidemiological situation of FMD in Nigeria, and will ultimately help to develop effective control and preventive strategies for the disease in Nigeria and other countries in the West African sub region.

Technical Abstract: The epidemiological situation of foot and mouth disease virus (FMDV) is uncertain in Nigeria, where the disease is endemic, and the majority of outbreaks are unreported. Control measures for FMD in Nigeria are not being implemented due to the absence of locally produced vaccines and an official ban on vaccine importation. This study summarizes the findings of a 3-year study aimed at quantifying the seroprevalence of FMD, its distribution in susceptible species and the genetic diversity of FMDV isolated from the Plateau State of Nigeria. A 29 percent FMD prevalence was estimated using 3ABC enzyme-linked immunosorbent assay (3ABC-ELISA). Five FMDV serotypes, (A, O, SAT1, SAT2 and SAT3) were detected by the virus neutralization (VN) test at various titres (less than100 – greater than 800) from all tested sera from most parts of the region. This is the first report of the presence of FMDV SAT3 in Nigeria. Tissue samples collected from clinical animals were positive for FMDV. Virus isolates were sequenced and confirmed as serotype A. All of the isolates showed marked genetic homogeneity with greater than 99 percent genetic identity in the VP1 region, and were most closely related to a previously described virus collected from Cameroon in 2000. This study provides knowledge on the epidemiological situation of FMD in Nigeria, and will ultimately help to develop effective control and preventive strategies for the disease in Nigeria and other countries in the West African sub region.