RESUMO
Objective: to determine serological prevalence rate of infection of sheep with IBR virus in Chaharmahal-Bakhtiary province
Design: cross - sectional study
Animals: four hundred and two healthy sheep
Procedure: serum samples were collected from 402 sheep during four seasons of 2002-2003 in all townships of Chaharmahal - Bakhtiary province by cluster random sampling method. Charactristics of the animals [age, sex and history of abortion] were recorded. Sera were tested for antibodies against IBR virus by the serum neutralization test
Statistical analysis: Chi-square, Linear regression
Results: serum samples from 43 [10.7%] sheep were positive. Prevalence rate of seropositive animals in all 5 townships of the province was estimated. No relationship was found between township, sex, season, previous record of abortion and IBR infection in sheep. Linear regression test indicated a relationship between age and prevalence rate of infection [r = 0.94]