Nucleotide sequence of the VP1 gene of the foot-and-mouth disease virus strain A Venceslau

Genetic analysis of foot-and-mouth disease virus serotype A of Indian origin and detection of positive selection and recombination in leader protease-and capsid-coding regions

The leader protease (L pro) and capsid-coding sequences (P1) constitute approximately 3 kb of the foot-and-mouth disease virus (FMDV). We studied the phylogenetic relationship of 46 FMDV serotype A isolates of Indian origin collected during the period 1968-2005 and also eight vaccine strains using the neighbour-joining tree and Bayesian tree methods. The viruses were categorized under three major groups -Asian, Euro-South American and European. The Indian isolates formed a distinct genetic group among the Asian isolates. The Indian isolates were further classi?ed into different genetic subgroups (<5% divergence).Post-1995 isolates were divided into two subgroups while a few isolates which originated in the year 2005 from Andhra Pradesh formed a separate group. These isolates were closely related to the isolates of the 1970s. The FMDV isolates seem to undergo reverse mutation or convergent evolution wherein sequences identical to the ancestors are present in the isolates in circulation. The eight vaccine strains included in the study were not related to each other and belonged to different genetic groups. Recombination was detected in the L pro region in one isolate (A IND 20/82) and in the VP1 coding 1D region in another isolate (A RAJ 21/96). Positive selection was identi?ed at aa positions 23 in the L pro (P < 0.05; 0.046*) and at aa 171 in the capsid protein VP1 (P < 0.01; 0.003**).

Extensive antigenic and genetic variation among foot-and-mouth disease type A viruses isolated from the 1994 and 1995 foci in São Paulo, Brazil

Nine foot-and-mouth disease virus (FMDV) type A isolates recovered from the field FMD foci in São Paulo State, Brazil, during 1994 and 1995 (a period preceding the last reported focus of FMD in 1996 in this state) were compared among themselves and with the reference vaccine strain A(24)Cruzeiro. The techniques used were sandwich ELISA, virus neutralization (VN), polyacrylamide gel electrophoresis (PAGE) of the structural polypeptides and direct sequencing of the VP1-coding region (1D gene). Results of VN were recorded as serological relationships "R" and those from ELISA were expressed as percentage of the homologous reaction "r". ELISA and VN gave comparable results (correlation coefficient, 0.936) allowing assignment of these field viruses to four groups which were distinct from the A(24)Cruzeiro strain. PAGE and 1D nucleotide sequencing were also able to distinguish between these viruses. The high level of genetic and antigenic variation found when comparing the A(24)Cruzeiro vaccine strain and type A strains recovered from the last identified foci of FMD came from a formerly endemic area where vaccination with polyvalent vaccines (O(1)Campos, A(24)Cruzeiro and C(3)Indaial) had been extensively applied. The similarity between the results of the serological and genetic analyses suggest that the antigenic differences found are mainly located in the 1D protein.

Subtyping of European foot-and-mouth disease virus strains by nucleotide sequence determination

The VP1-coding regions of foot-and-mouth disease virus strains from 18 recent European outbreaks and of 9 strains isolated more than 20 years ago and used in part as vaccines were determined by direct cDNA sequencing. Comparison of the sequences revealed that most of the isolated outbreak viruses are closely related to the vaccine strains used. Isolates from the Italian epizootic of 1984 to 1985 correspond, for example, to the vaccine strain A5 Parma 62; the outbreak in 1984 in Bernbeuren, Federal Republic of Germany, was induced by A5 Allier 60; outbreaks in 1982 in Funen, Denmark, and in Murchin, German Democratic Republic, were caused by O1 Lausanne 65. Viruses isolated during the 1983 Iberian epizootic show a close relationship to the vaccine strain A5 Allier 60 but were probably derived from another not yet identified vaccine strain from Spain. Only two minor outbreaks in the Federal Republic of Germany, A Aachen in 1976 and O Wuppertal in 1982, did not correspond to the classical European strains but were obviously introduced from outside. We suggest that nucleotide sequence analysis should be used as a standard method of diagnosis, because when compared with other techniques it more clearly reveals the origin and course of epizootics and offers the possibility of preventing further outbreaks.