Outbreak investigation and molecular characterization of African horse sickness virus circulating in selected areas of Ethiopia.

The research article outlines an investigation and identification of the African Horse Sickness Virus (AHSV) within selected regions of Ethiopia, which took place between June 2011 and May 2012. It focuses on both the knowledge of equine owners in the region and retrospective data from 2011 AHSV outbreaks and employs various lab techniques, including virus isolation, to identify the circulating AHSV serotypes.

Aim and Methodology

• The study was primarily carried out to detect and identify the circulating serotypes of the African Horse Sickness Virus (AHSV) in central, northern, and western parts of Ethiopia over a 12 month period.
• It involved an assessment of equine owners’ local knowledge about AHSV, an analysis of retrospective data from 2011 AHSV outbreaks, and the collection of whole blood samples from diseased animals noticeable by typical AHSV symptoms.
• Virological techniques used to identify the serotypes included virus isolation on Vero cells and the detection of AHSV genomes using conventional RT-PCR, a process that amplifies the virus’s genetic material for easier detection.

Results

• Data retrieved from the questionnaire survey indicated that equine owners within the studied areas had knowledge of AHSV’s clinical manifestations, and even assigned local names to the disease, which diverged across different regions.
• However, out of the 72 equine owners interviewed, 66.7% were unaware of how the virus is transmitted.
• The study’s review of retrospective disease data revealed that in 2011, 208 AHSV outbreaks were reported with 3,036 diagnoses and 1,167 equine fatalities. The frequency of AHSV outbreaks peaked from September to December, with the highest count in October.
• During the study period itself, six outbreaks were investigated. A total of 62 horses and 10 mules were found to display symptoms of AHSV, with the disease manifesting in four different forms: Cardiac (most common, representing 52.8% of cases), AHSV fever (31.9% of cases), Pulmonary (8.4% of cases), and Mixed (6.9% of cases) forms.
• After molecular characterization and serotyping, AHSV-9 was identified as the sole circulating serotype during the outbreaks within these geographical areas.