Bluetongue virus in a Nigerian dairy cattle herd: 1. Serological studies and correlation of virus activity to vector population

Abstract

Newborn calves were bled at monthly intervals and examined for serum antibodies to blue tongue virus (BTV). Maternal immunity persisted for 3 months and it was possible to calculate decay rates for virus neutralizing antibody. Calves were subclinically infected with BTV within a few months of becoming susceptible and neutralization tests were used to deduce the serotype responsible. A profile of virus activity was built up over a 12 month period. Frequent light trap catches were used to examine the population dynamics of suspected Culicoides vector species. Two species, imicola and schultzei were present throughout the wet and dry seasons and survival were sufficiently long to account for virus transmission at any time of the year.

Bluetongue virus and epizootic haemorrhagic disease of deer virus serotypes in northern Colombian cattle

“…Type-specific antibodies to BT and EHD were determined by the microneutralization test (Herniman, Boorman & Taylor, 1983). This test-was used only for sera of animals two years of age or less.…”

Isolation of bluetongue and related viruses from Culicoides spp. in the Sudan

“…The isolates were checked against all 22 known serotypes of BTV and against Akabane virus, Ibaraki virus and two unidentified viruses from Sudanese cattle, using the method of Herniman, Boorman & Taylor (1983).…”

The epidemiology of bluetongue in Malawi

“…However, there is evidence that in some parts of Africa bluetongue virus has a seasonal occurrence (Theiler, 1908;Herniman, Boorman & Taylor, 1983;Mohammed & Taylor, 1987) and that within the continent as a whole, endemic and epidemic zones occur (Sellers, 1981). This suggests the possibility that in some countries there will be periods when the virus is absent, during which stock introductions and preliminary vaccinations could take place without threat.…”

“…The present results are from a 4-year study of the seasonality and distribution of bluetongue virus types in the Central Region of Malawi. It was based on the use of sentinel cattle rather than sheep, because calves were more readily available and had been used successfully in this capacity in previous studies (Herniman, Boorman & Taylor, 1983 (Herniman et al 1983). …”