Bluetongue virus seropositivity in sheep flocks in North West Frontier Province, Pakistan

The objectives of this study were to describe the prevalence and distribution of serum antibodies to Bluetongue virus (BTV) in a sample of 38 sheep flocks in northern areas of the North West Frontier Province of Pakistan and to identify demographic and productivity variables that are associated with BTV seropositivity. Blood samples were taken from a random sample of ewes in each flock in April 1995. The owners of the flocks were interviewed regarding some demographic, husbandry and productivity variables of the flocks on the day of blood sampling. A competitive enzyme-linked immunosorbent assay was conducted to test the serum samples for BTV group-specific antibodies. BTV seropositive reactions were obtained in 184 (48.4%) out of 380 tested sera, and in 89.5% (34/38) of the flocks. In the 34 seropositive flocks, the prevalences ranged from 12.5 to 100% (median = 47). A multivariable logistic analysis was carried out to study the influence of demographic and productivity variables on the BTV serological status of the sheep flocks. Abortion risk in the previous lambing season was mildly associated with the serological status of the flock (adjusted odds ratio = 1.16, P = 0.07). For the seropositive flocks, a linear multiple regression showed that distance travelled by the flock during transhumant movement was significantly associated with percent seropositivity (partial regression coefficient (± SE) = − 0.091 ± 0.045).     

Pregnancy rate and conception date in a wild population of Japanese monkeys

This study is the first to determine the conception dates of specific individuals and estimate the pregnancy rate of a wild population in Japanese monkeys. The conception dates estimated from the embryonic ages of 37 fetuses were distributed over 128 days between September 17 and January 23, with a mean conception date of November 19 (SD=29.2 days). A comparison of the mean conception dates among age groups showed a significantly delayed conception in the subadult animals (aged 4 to 5 years; December 5, n=8) than in the adult animals (aged 6 or more years; November 15, n=29; P<0.03). The mean pregnancy rate among animals aged 4 years or more in this local population was estimated to be 48.5% (32/66).