Seroprevalence and molecular identification of footand mouth disease virus

Abstract

Outbreaks of vesicular disease that occurred in Elmowayleh, Hillat Kuku, and in a dairy farm in Elsagai area were investigated. Clinical signs included salivation, lameness, loss of appetite and decrease in milk production. The samples collected were serum, and saliva. Saliva samples were transported to the laboratory on ice and stored at -20 °c. Liquid phase blocking ELISA was performed for antibody detection and typing of the FMDV on 24 serum samples from Almowayleh market, 6 samples from Hilat Ku Ku, and 10 serum samples from Elsagai against types O, A, SAT1 and SAT2, using a kit purchased from Pirbright laboratory (Institute for Animal Health, Pirbright, UK). Diluted serum samples (1:32), were subjected to the test according to the instructions provided with the kit. In this study, incidence of serotype O was 100% in Hilat KuKu, 95.6% in Almowaleh and 90% in Alsagai. Incidence for serotype A was 83.8% in Hilat KuKu, 58% in Almowaleh and 40% in Alsagai. Incidence for serotype SAT1 was 66.7% in Hilat KuKu, 70.8% in Almowaleh and 20% in Alsagai, and for type SAT2 was 66.7% in Hilat KuKu, 87.5% in Almowayleh and 70% in Alsagai. The overall results shows that 12 serum samples were positive to the 4 serotypes, 17 serum samples were positive to 3 serotypes, 7 serum samples were positive to 2 serotypes and 1 serum sample was negative to all serotypes. The overall results in Khartoum state indicated that antibodies against type O are the most prevalent (95%) followed by type SAT2 (80%) and then type A and SAT1 (57%). Statistical analysis revealed that, there are significant difference between negative and positive sera for serotypes O, A, SAT1, and SAT2. There are no significant difference between localities studied in regard to type O and type SAT1. However in Almowaleh and Elsagai there is no significant difference in serotypes A and SAT2 but there is significant difference in Hilat KuKu. Additionally RNA was extracted from three saliva samples collected from sick animals from Elsagai, and from a commercial polyvalent vaccine used as a positive control RNA using RNA isolation kits (PUREGENE). The RNAs were subjected to reverse 8 transcriptase PCR (RT-PCR) using oligonucleotide primer sequences originated from the conserved region of the 3D polymerase gene. The control positive RNA and the RNA extracted from the three saliva samples gave positive results (product size 131bp). Sera collected from respective animals revealed the detection of serotype O and SAT2, with one sample positive to serotype A.