Circulation of bluetongue virus in goats in the Karamoja region of Uganda

Elijah N Mulabbi,Carrie A Batten,Christopher A.L Oura,Chrisostom Ayebazibwe,Samuel Majalija

doi:10.4102/jsava.v84i1.922

Abstract

The presence of bluetongue virus (BTV) in indigenous goats from the Karamoja region of northern Uganda was investigated. A total of 300 goats were sampled (serum and whole blood) from five districts within the Karamoja region. The samples were analysed for the presence of bluetongue (BT) antibodies using a commercial Enzyme-linked immunosorbent assay (ELISA) and for the presence of BTV viral RNA by real-time Reverse transcription polymerase chain reaction (RT-PCR), because BTV is an RNA virus. Of the 300 goats tested, 269 (90%) were positive for BTV antibodies, indicating high levels of BTV circulation within the region. Out of the 150 whole blood samples tested for the presence of the virus by real-time RT-PCR, 84 (56%) were positive for BTV RNA. This study, which is the first of its kind in Uganda, showed a high seroprevalence of BT antibodies and active circulation of BTV in a high proportion of goats in the Karamoja region.

Highlights

Bluetongue virus (BTV) is a member of the genus Orbivirus, family Reoviridae (Mertens et al 2005) and is transmitted by biting midges (Culicoides spp.)
The blood samples were transported at 4 °C to the National Animal Disease Diagnostics and Epidemiology Centre (NADDEC), Ministry of Agriculture Animal Industry and Fisheries (MAAIF), Entebbe
Reverse transcription polymerase chain reaction (RT-PCR) was used because BTV is an RNA virus, and this method first synthesises complementary deoxyribonucleic acid (DNA) before PCR amplification

Summary

Introduction

Bluetongue virus (BTV) is a member of the genus Orbivirus, family Reoviridae (Mertens et al 2005) and is transmitted by biting midges (Culicoides spp.). Bluetongue (BT) disease is an infectious, arthropod-borne viral disease caused by BTV. It is found in sheep and both domestic and wild ruminants, such as goats, cattle, deer, bighorn sheep, most species of African antelopes and other artiodactyls (MacLachlan 1994). The central role of the insect in BTV epidemiology ensures that the prevalence of disease is governed by ecological factors, such as high rainfall, temperature, high humidity and high organic matter content of the soil, which favour insect survival. In many parts of the world the disease has a seasonal occurrence (Erasmus 1990)

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