Isolation and (serological and molecular) identification of foot and mouth disease virus from cattle in Khorasan Razavi province.

Foot-and-Mouth Disease (FMD) virus is a member of Picronaviridae family and causes a highly contagious and economically important disease of domestic and wild cloven-hoofed animals. There are seven serotypes of virus. Types O, A and C are widely distributed, whereas serotypes SAT1-3 are normally restricted to Africa and serotype Asia1 to Asia.Becuse genetic variation accumulates rapidly in the field, early detection of infected animals is essential for an effective control of the disease, and requires a rapid and sensitive method of diagnosis . For laboratory diagnosis the tissue of choice is epithelium. The samples are tested routinely and serotyped by combined use in cell culture and ELISA. Types O, A and Asia1 FMDV are endemic in Iran now. This study was conducted in Khorasan-Razavi province for 23 months (from February 2004 to December 2005). Samples were collected from suspected livestock (cattle and sheep with clinical symptoms).The samples were then analyzed with CFT, ELISA, RT-PCR and cell culture experiments. During this study twelve foci in year 2004 and twenty tree in year 2005(up to December) were approved. In this survey, 33.3% suspected samples were positive with CFT, 39.7% with ELISA, 46.9% with RT-PCR and 20.8% with virus isolation in BA cell culture .Based on the results, 63% of the isolation FMDV were observed during the study in spring. We have compared the sequence and phylogenetic analysis of two O types, two Asia1 types and one A type of FMDV isolated in Khorasan-Razavi with other isolated of Iran and neighboring countries. Pearson&rsquos correlation coefficient and Chi-square tests (SPSS software), Blast (NCBI) and BioEdit software were used for data analysis. Type O field strains showed 99% internal similarity and 5 %( average) divergence from others. Type Asia1 field strains showed 98% internal similarity and 11 %( average) difference from others, and Phylogenitic analysis identified two different lineages .Type A field isolated showed 89% similarity with others (isolated in Iran and neighboring countries) .The virus was closely related to A22-Iraq and A-IR-iso-105. . Data shows that type O viruses rampant in the Khorasan-Razavi province were antignically similar to the O/IRN/vaccine (Vaccine strain) but probably didn&rsquot originate from these strains. In Comparison, isolated type A, showed a 39 nucleotide deletion in the G-H loop region of VP1 causing loss of 14 amino acids in the vaccine strain. With respect to the sensitive age of lambs to FMD and the frequent traffic of livestock (especially sheep) in spring, increase of the disease in this season must be considered. Because, high tendency of type O toward sheep, and with respect to considerable sheep population in Iran and its role in persistence of the virus. The vaccination of sheep seems crucial. ‎