Scientists in the Non-Vesicular Reference Laboratory (NVRL) at The Pirbright Institute have confirmed an outbreak of African horse sickness (AHS) in Thailand. AHS is the most lethal viral disease of horses known and the rapid diagnostic services provided by Pirbright has enabled authorities to respond quickly to the outbreak, the first that south-east Asia has ever experienced.
As a designated AHS reference laboratory for the World Organisation for Animal Health (OIE), Pirbright tests samples sent from around the globe to verify suspected infections. Samples from Thailand were confirmed African horse sickness virus (AHSV) positive by Pirbright scientists and further testing established that AHSV serotype 1 had caused the outbreak; the first time that this serotype has been seen outside of Africa.
AHSV is spread mainly by Culicoides biting midges and Thailand has several species that have previously been implicated in the spread of viruses. There are nine serotypes of virus and knowing which is involved in an outbreak is important in choosing an effective vaccine, the only certain way of controlling epidemics. In populations of horses that have never been exposed to the disease, case fatality rates can reach 80-90 percent, although zebra and donkeys generally suffer much milder disease.
Within Africa, AHS outbreaks impact low-income countries where animals like horses and donkeys are relied upon for ploughing and moving goods, affecting income and food security. In contrast, AHS also threatens the billion dollar horse racing industry, where the importation of thoroughbreds can pose a risk to countries both inside and outside of Africa. The degree of spread during an outbreak is reliant on the presence of susceptible hosts, vector species of Culicoides to transmit the virus and suitable climatic conditions to allow replication of AHSV in the midges.
Dr Carrie Batten, Head of the NVRL, said: “The identification of AHSV in Thailand is unprecedented and demonstrates the fact that this virus can emerge without warning in new areas. Having the ability to collaborate with groups from around the world to ensure accurate diagnosis is therefore vital in combatting these threats”
Dr Simon Carpenter, Head of National Capability at Pirbright and AHS OIE expert said: “The work of the NVRL is vital in underpinning disease intelligence worldwide, alongside sharing expertise and experience in virus outbreaks. The aim is to be able to respond to outbreaks of viral diseases like AHSV using expertise from a wide range of backgrounds and to work closely with those affected by the disease”.
Notes to editors:
The Pirbright Institute provides national and international reference laboratory services for 10 viral diseases of livestock, and includes the World Reference Laboratory for Foot-and-Mouth Disease. Through these laboratories, Pirbright provides essential advice and diagnostic services to the UK Government (Defra), United Nations Food and Agriculture Organisation of the United Nations (FAO), and the World Organisation for Animal Health (OIE).
The Non-Vesicular Reference Laboratory Group brings together all the reference laboratories working on non-vesicular diseases at Pirbright. These diseases include bluetongue (BT), African horse sickness, African swine fever, peste des petits ruminants, rinderpest (which was declared eradicated in May 2011), lumpy skin disease, sheep pox and goat pox.
The group was instrumental in diagnosing the first ever incursion of BT into northern Europe in 2006, the first outbreak of BT in England in September 2007 and the first outbreak of African swine fever in Georgia in 2007.
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About The Pirbright Institute
The Pirbright Institute is a world leading centre of excellence in research and surveillance of virus diseases of farm animals and viruses that spread from animals to humans. Based in the UK and receiving strategic funding from the Biotechnology and Biological Sciences Research Council, part of UK Research and Innovation (BBSRC UKRI), the Institute works to enhance capability to contain, control and eliminate these economically and medically important diseases through highly innovative fundamental and applied bioscience.
With an annual income in excess of £35 million from grants and commercial activity, and a total of £12.6 million strategic investment from BBSRC during 2018-2019, the Institute contributes to global food security and health, improving quality of life for animals and people.
For more information about The Pirbright Institute see: www.pirbright.ac.uk