AHS Trust Outbreak Report
AHS TRUST OUTBREAK REPORT – 31 March 2011
During the last 30 days ( March), we have received 413 reports of suspected cases of AHS from most parts of the country normally affected by AHS during outbreaks.
In the six years that the AHS Trust has been reporting on outbreaks, this year has recorded the highest number of suspected cases up until the 31st of March 2011. Please note - this is based on suspected cases reported but not yet substantiated by laboratory results or veterinary diagnosis.
The specific breakdown of cases reported by Province and by Month can be found on the table at the end of this report.
No full analysis has yet to be done on the outbreak but at this early stage I can say that it appears that the outbreak has effected many more parts of the country due to climatic conditions. We have had reported cases of AHS in areas that have not reported cases for in excess of 40 years and therefore have a naive population of horses and very high mortality especially in horses under 4 years.
To be specific about cases captured to date, it seems like the mortality on un-vaccinated cases is around 85% and on vaccinated cases lower than 30%. Farm horses and stud horses are the majority of our cases ( horses that live out permanently) The permanently stables horses like race horses only are 2% of cases.
Western Cape Outbreak
The State Vet is using the AHS Trust website to publish the Situation Reports of the outbreak in the Western Cape. For detailed up to date information go to:
All other infected areas
We have recorded outbreaks in most of the usual parts of the country except for the far north where it is reported to be exceptionally dry for this time of year. Of concern are the locations that have reported cases not usually associated with AHS outbreaks, especially at this time of the year. These include the following areas:
· Eastern Free State – Wakkerstroom, Memel, Bethlehem, Harrismith, Warden and Kestel
· Mpumulanga – Amersfoort
· Northern Cape – Hotazel, Vryburg, Kuruman
In Harrismith and surrounding areas, where no cases have been reported for the last 40 years, in excess of 150 cases have been mentioned by the local vet Dr Scheepers however only 32 cases have been reported to the Trust. This is an indicator of the underreporting that exists during outbreaks.
Typically suspected cases reported in March account for about 60% of the total received in the season. Therefore, it would be reasonable to expect an increase in suspected cases from this point onwards which also appears to fit the five-year cycle based on the history of AHS reporting.
Historically, at least 30% of cases are reported on average two weeks after the event which means that the number of cases from March and current will increase considerably.
Higher vaccination coverage in the rural areas of KZN and the Eastern Cape hopefully will reduce the impact in these areas. The AHS Trust inoculated 2500 horses in the blanket vaccination campaign of 2011.
This year, samples collected via the AHS Trust reporting system have been couriered to Equine Research Centre (ERC) which then splits them and delivers to the State laboratory, Onderstepoort Veterinary Institute (OVI). We are also supporting Deltamune with samples.
Research initiatives are reliant on field samples and detailed reports and horse owners are encouraged to send in as many samples as possible as well as report all cases. Please contact Douglas Welsh on 082 9654082 in this regard.
Douglas Welsh (Chairman)
Friday, 1 April 2011