Genetic analysis of type O viruses responsible for epidemics of foot-and-mouth disease in North Africa

The nucleotide sequences of the 3' end of the capsid-coding region were det ermined for 30 serotype O foot-and-mouth disease (FMD) viruses isolated bet ween 1987 and 1994 from outbreaks in North Africa and the Middle East. Thes e sequences were compared with the previously published sequences of 9 fiel d virus isolates from the Middle East and 5 vaccine virus strains, 3 of whi ch originated from the Middle East (O-4/Turkey/Manisa/69, O-1/Sharquia/Egyp t/72 and O-1/Israel/2/85) and 2 from Europe (O-1/Lausanne/ Switzerland/65 a nd O-1/Brescia/Italy/47). Cluster analysis of these sequences using the unw eighted pair group mean average (UPGMA) method showed: (i) that the FMD vir uses isolated from North Africa and the Middle East were very different fro m the classical European vaccine strains; (ii) that all the viruses isolate d during the 1989-92 North African epidemic formed a cluster differing by n o more than 6% from each other; (iii) a virus isolated in Libya in 1988 was unrelated to the aforementioned epidemic; and (iv) viruses from a second, less extensive epidemic, occurring in 1994, fell into yet another cluster.