EPIDEMIOLOGY REPORT WESTERN CAPE DEPARTMENT OF AGRICULTURE VETERINARY SERVICES

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EPIDEMIOLOGY REPORT Volume 3, Issue 9 September 2011 WESTERN CAPE DEPARTMENT OF AGRICULTURE VETERINARY SERVICES Until recently, Contagious Equine Metritis (CEM) was considered to be absent from South

In April 2011, however, the disease was confirmed in three stallions and a mare, and since testing began a number of other horses have tested positive to CEM.

1 EPIDEMIOLOGY REPORT Volume 3, Issue 9 September 2011 WESTERN CAPE DEPARTMENT OF AGRICULTURE VETERINARY SERVICES Until recently, Contagious Equine Metritis (CEM) was considered to be absent from South Africa, owing to strictly observed quarantine measures. In April 2011, however, the disease was confirmed in three stallions and a mare, and since testing began a number of other horses have tested positive to CEM. The first (and only thus far) confirmed case occurred in the Western Cape at the end of August 2011 in a stallion near Stellenbosch. The stallion in question had come into the Western Cape from Kyalami in Since that date, it has not had the opportunity to mate naturally, but has sired three foals by artificial insemination. The property has been quarantined and investigations and tracing are underway. The causative organism of CEM, Taylorella equigenitalis, is a gram-negative, short cocco-bacillus that can be carried by both stallions and mares. Zebras can also be infected by this bacterium, but donkeys are naturally resistant. While stallions are asymptomatic when infected, an acute, transient metritis occurs in mares that usually causes a temporary infertility. This can have serious implications in breeds such as the Thoroughbred, where only a short breeding season occurs and the use of natural mating is compulsory. The disease is highly contagious, but occurs strictly in the genital tract and can be killed within 10 minutes by several common disinfectants. Transmission is therefore usually venereal, but fomites and indirect transmission through, for example, nasal-genital contact, can also play a role. Infection may spread from acutely infected mares, carrier mares, infected stallions or from congenitally infected foals that have become sexually active. Only one in three mares become infected and show clinical signs after being served by an infected stallion. A very small percentage of those that do not show clinical signs can become chronic carriers of the disease. Unfortunately poor immunity develops in infected horses, allowing them to be re-infected repeatedly. In order to determine the extent to which the disease is currently present in South Africa, and to try prevent the disease from becoming endemic in RSA, all stallions must be tested negative at least twice with an interval of no less than seven days before being allowed to breed or have semen collected. Taylorella equigenitalis Contagious Equine Metritis (CEM) Samples must be taken by registered veterinarians only, using sterile technique for each animal, and storing the swabs dry, without contact media. When sampling a stallion, the penis must be fully extruded and an individual swab taken from each of the urethra, urethral fossa and sinus and the lamina interna. Three swabs must therefore be submitted within 48 hours of collection to the Equine Research Centre at Onderstepoort along with the correct sample submission form. After two negative results have been obtained from a particular stallion, an official CEM clearance certificate will be issued, after which breeding using the stallion will be permitted. A list of CEM-cleared stallions is accessible on Any suspect or confirmed positive case of CEM must be reported immediately to the relevant state veterinary official in the area in which it has occurred.

2 Figure 1. An indication of all AI H5 positive farms identified during the various rounds of surveillance within the AI control area in Oudtshoorn during the AI campaign and outbreak of VOLUME 3, ISSUE 9 2

VOLUME 3, ISSUE 9 The World Veterinary Congress is being hosted in the Western Cape Province this year.

Society of Veterinary Epidemiology and Preventive Medicine).

our surveillance zone in the WCP and the ongoing avian influenza virus outbreak near Oudtshoorn.

3 VOLUME 3, ISSUE 9 The World Veterinary Congress is being hosted in the Western Cape Province this year. It is being held during the week of the 10th-14th of October, with a number of topical streams, including an Epidemiology stream which was included in conjunction with SASVEPM (Southern African Society of Veterinary Epidemiology and Preventive Medicine). The invited speaker in the epi stream is Dr Angus Cameron who will be giving a series of talks with a focus on Disease Surveillance, which is currently quite topical given the recent AHS outbreak in our surveillance zone in the WCP and the ongoing avian influenza virus outbreak near Oudtshoorn. A number of speakers who work closely and assist the epidemiology side of Veterinary Services in the Western Cape are also attending and speaking at the congress, including Prof Lucille Blumberg and Alan Kemp (speaking on behalf of Prof Janusz Paweska) who assist us regularly with information regarding diseases like Rabies and Rift Valley Fever. The congress program is jam packed and will hopefully prove to be very interesting indeed. Veterinary officials from the Swellendam State Vet area (Thuli Tsele and Werner Gouws in picture) were involved at the annual Agri Mega Week in the Overberg during September. Roelof Mare and Gerhard van Wyk (in picture below) also helped organise a series of lectures presented by the Epidemiology Section for the SANPARKS Agulhas Honorary Rangers at Struis Bay during September. Information on rabies, Rift Valley fever and avian influenza was presented. Epidemiology does not only include studying diseases within populations but is also tasked with disseminating information, which is what makes sessions like these so important. Avian Influenza - Mini update The 5th round of the AI surveillance within the AI control area has been completed with one new farm testing sero-positive. Planning for this farm s stamping out is underway. The EU have provisionally acknowledged that ostrich meat export may resume to their member countries, but only from registered export farms outside of the AI control area. Planning for the following round of surveillance is underway. See the Map on page 2 of this report for a spatial temporal representation of the positive AI farms identified in the AI control area thus far. 3

4 4 VOLUME 3, ISSUE 9

Schematic representation of laboratory tests for determining evidence of NAI infection through or following serological surveys - OIE Terrestrial Animal Health Code 2011 VOLUME 3, ISSUE 9 African

5 Schematic representation of laboratory tests for determining evidence of NAI infection through or following serological surveys - OIE Terrestrial Animal Health Code 2011 VOLUME 3, ISSUE 9 African Horse Sickness investigation in the Protection Zone A positive PCR result for African Horse Sickness was received from a Percheron stallion which had died on a farm near Worcester in the Western Cape Province. This result was unexpected at the time as a diagnosis of Pseudomonas pneumonia had been established by the private vet involved and the AHS sample tested was on culture product from a post mortem tissue sample sent for virus isolation. The horse was an 11-year old imported stallion from the UK. He had been vaccinated against AHS twice in quarantine in RSA in the Kempton Park quarantine facility prior to moving down to Beaufort West in a stepwise transfer to the Worcester area. The quarantine period in Kempton was during July and the beginning of August and he had tested negative to AHSV twice prior to moving down to Worcester, once just prior to his second AHS vaccine and once in Beaufort West. He moved to Worcester during the middle of August and died on the 23/8/2011. It was evident that the AHS positive PCR result may have been a result of the AHS vaccinations the horse received relatively soon before its death, and indications were that the AHS result had no influence on the cause of death of this animal. In order to remain thorough all other equines on the property in Worcester were sampled and tested for evidence of AHSV. Duplicate samples were sent to two different testing facilities and all results were fortunately negative. The picture (right) shows the horse with Dr Pienaar in Beaufort West just prior to its travel to Worcester. The owners and all involved in the import were devastated when the horse died, it was a beautiful stallion and would have added valuable genetic material into the South African Percehron gene pool. IDEXX ELISA Evaluation and Validation The epidemiology section has played an integral part in the validation of an IDEXX ELISA assay which can now be used for AI surveillance in ostriches in South Africa. The schematic below illustrates the sero-surveillance pathway for avian influenza and the orange line is the path South Africa follows in ostriches - as they are an unvaccinated population. The recommended first step is a screening test (Blue oval) and all positive results from here are tested using a more specific assay (HI - Yellow rectangle in schematic) to confirm the AI H subtype. Until the ELISA was validated in RSA the blue step was omitted from our ostrich AI surveillance, and only HI assays were used. We can now move to a more standardised screening step using the ELISA first without having to immediately test using the HI assay. Many thanks to all animal health technicians and state vets from the George and Swellendam offices who assisted in this validation 5

6 VOLUME 3, ISSUE 9 THE BACK PAGE Outbreak Events Another case of rabies has been diagnosed in Bat-eared foxes in the Malmesbury state vet area. The incident was identified when a bat-eared fox attacked a group of farm workers while they were working with sheep. One worker was bitten on the foot but the bite fortunately did not penetrate his gumboot. Dogs and cats in the vicinity are being vaccinated against rabies. The case was confirmed after whole brain was taken from the killed fox and tested positive to rabies at Allerton. Sheep scab continues to be identified in the Malmesbury district. An outbreak that has probably been ongoing for some time was identified near Halfmanshof and sheep have since begun treatment, with a quarantine placed on the property. A similar situation was also identified in the Riversdale district where sheep scab was identified in September but the infection may have been present from April In this case the potential introduction of the infection was via rams which were introduced into the small flock of sheep. As per procedure quarantine was issued and treatment under official supervision started. Newcastle disease has been identified in domestic poultry in the Napier and Malmesbury districts. The Napier case occurred in July 2011 and clinical symptoms (neurological) associated with NCD were noted in 16 of 78 chickens. The flock was subsequently vaccinated against NCDV. The case in Malmesbury occurred in a broiler house of birds. The infection was picked up early on routine sampling and the house was slaughtered out with no identified spread of the virus. This outbreak was resolved in this way, but unfortunately there is a registered export ostrich farm within 10 km of this outbreak which causes its export status to be suspended temporarily. Brucella ovis infections have been identified on three different farms in the Vredendal state vet area. Two of these farms are epidemiologically linked with one farmer buying in rams from the other. The source farm in this case has now tested positive to B. ovis for two years running. This illustrates the importance of maintaining a regular testing routine for this disease, and not only in the pretesting of rams presented at auction. Of these three farms the management on one only deems it necessary to test regularly and not only for pre-auction requirements. Please visit for more information on this disease. SV Area User Total Logs September Malmesbury Hendrik Hagen 62 Malmesbury Esthea Jordaan 47 Malmesbury Michael Chapman 42 Boland Janica Fourie 34 Beaufort West Nita Vosloo 17 Swellendam Eugene Du Plessis 15 Disclaimer: This newsletter is published on a monthly basis for the purpose of providing up-to-date information regarding epidemiology of animal diseases in the Western Cape Province. Much of the information is therefore preliminary and should not be cited/utilised for publication 6

EPIDEMIOLOGY REPORT. National Foot and Mouth Disease Survey Western Cape participation and initial coverage. Introduction.

EPIDEMIOLOGY REPORT. National Foot and Mouth Disease Survey Western Cape participation and initial coverage. Introduction. EPIDEMIOLOGY REPORT National Foot and Mouth Disease Survey Western Cape participation and initial coverage Introduction DAFF embarked on an FMD survey on a country- wide basis which was scheduled to begin