Seroepidemiological survey of infection bovine herpesvirus type 1 (BoHV-1) in cattle in the State of Pernambuco.

Background: The infection of virus the Infectious Bovine Rhinotracheitis (IBR) is responsible for variety of clinical signs in cattle, highlighting problems in the reproductive tract which causes damage to the cattle. The objective of this work was to determine the prevalence and risk factors associated with infection by bovine herpesvirus type 1 (BoHV-1) in cattle herds in the micro Garanhuns, State of Pernambuco, Brazil. Materials, Methods & Results: Samples of 373 cows of reproductive age were collected (over 24 months), with milk aptitude and seven bulls, totaling 380 samples from herds without history of BoHV-1 vaccination, from 20 properties distributed in the municipalities that make up the study area during the months of April and May 2013. For serological diagnosis of infection with BoHV-1, we used the virus neutralization test (VN). In each farm, an epidemiological questionnaire to analyze risk factors with objective questions about the characteristics of production and aspects of hygiene and sanitary and reproductive management was applied. The analyze the risk factors associated with BoHV-1, it was performed a univariate analysis of the variables of interest using the chi-square test of Pearson or Fisher exact test, when necessary. Then, a logistic regression analysis dependent variable considering how to BoHV-1 virus neutralization test result (no reagent or reagent) was performed. The independent or explanatory variables considered in the model were those that showed statistical significance < 0.20. The prevalence was 79.5% (302/380; CI: 75.1% -83.4%) of the 20 sampled properties, all had at least one positive animal, with prevalence in herds ranging from 46.2% to 100.0%. The variables considered risk factors for HBV-1 in the logistic regression analysis were: i) bulls used in the breeding season in females with reproductive problems (OR = 3.84, CI = 2.19 to 6.72; P < 0.000); ii) consortium Creating goats / sheep with cattle (OR = 2.90, CI = 1.00 to 8.37; P = 0.048); and iii) herd size < 50 animals (OR = 3.62, CI = 1.66 to 7.85; P = 0.001). Discussion: The results described vary considerably between countries and regions, however, we realize that the HBV-1 is widespread in the world with prevalence higher than 50%, as well as found in micro Garanhuns, State of Pernambuco. The reasons for the prevalence of variation found are explained by the wide variability of management systems, climate and environmental factors among the mentioned countries. Other factors that can be listed are the type of farming, management of animals, group or age group of animals used in research, sampling techniques, diagnostic methods, in addition to the regional characteristics of each study. The high prevalence of BoHV-1 infection found in cattle of micro Garanhuns shows great distribution of infection in dairy herds. Although this region focus much of milk production in the state of Pernambuco, the farmers during application of epidemiological questionnaires showed lack knowledge about the disease and possible consequences of infection, which may be contributing to the high prevalence. In logistic regression analysis was confirmed as a risk factor the use of bulls in the breeding season with females with reproductive problems (OR = 3.84). This probably occurs by the use of transfer of bulls for breeding bulls and loans on other properties as well, for mating with a large number of females, males are more susceptible to infection and thus become HBV-1 multipliers potent. These results indicate that infection with BoHV-1 is distributed in the study area and that control measures should be adopted in herds. Epidemiological data obtained will serve as a basis for planning control strategies, as the identified risk factors are related to creation and hygienic-sanitary management system.