Objective: The present study was conducted to estimate the seroprevalence and associated risk factors of bovine herpesvirus 1 (BoHV-1) in a dairy herd in the northeast of Algiers, Algeria. Materials and methods: The target area is in the northeast of Algiers with humid to semi-dry climate and known for its economically important production of cattle. A total of 1,066 randomly selected individual blood samples of dairy herd collected at 120 dairy farms from rural districts of northeast of Algiers were evaluated with antibodies against BoHV-1 using commercial enzyme-linked immunosorbent assay kits, to determine the BoHV-1 infection status of the herds. A questionnaire submitted to the farmers during collection of the blood samples was used to collect data on potential BoHV-1 associated risk factors. Results: In the present study, the estimated farm and individual animal BoHV-1 seroprevalence levels were 58.33% and 14.16%, respectively. A logistic regression analysis of the random-effects model revealed that the significant associated risk factors for the present farm and individual animal seroprevalence levels were rural district, cattle introduced to the farm, region, and hygiene. Conclusion: This study found higher seroprevalence of BoHV-1 in the northeast of Algiers. The results could be used in designing the prevention and control strategy of BoHV-1 in the northeastern part of Algeria.

During May-July 2014, a total of 837 cattle serum samples were collected from 4 departments in northern Algeria and tested for the presence of anti-Hypoderma antibodies by indirect ELISA. Warble counts and some intrinsic (age, breed, sex) and extrinsic factors (location, husbandry system) were also considered. The overall seroprevalence by indirect ELISA was 49.8%, whereas by clinical inspection only 25.7% of the animals were infested. Except for the sex, all the factors included in the study were significantly associated with seroprevalence. The husbandry system was identified as the factor with more influence in seroprevalence, so cattle kept under extensive (79%) or semi-extensive (50.6%) husbandry systems have 74.10 and 18.13 more risk than those under an intensive system (5.8%), respectively. Both the seroprevalence and the intensity of infection are inversely related with the age of the animals. So, the youngest animals (˂3 years) are less frequently infested but display the highest intensities of infection. The seroprevalence detected in northern Algeria reflects a high exposition of cattle to Hypoderma spp. To minimize the economic losses due to this myiasis it is essential to establish control programs based on serological surveillance prior to the administration of macrocyclic lactones. Keywords