GARDEN ROUTE NEWS - Veterinarians in the Garden Route have been inundated with countless enquiries about possible viral outbreaks of Equine herpes type 1 (EHV-1) and the West Nile virus (WNV) among horses in the Garden Route.
Since word of the viruses spread, some horse shows and competitions in the area have been cancelled or put on hold until there is more clarity about the current situation in the area.
According to Dr Martino Truter of the George Animal Hospital there have been two confirmed cases of EHV-1 in the area, one abortion due to EHV-1 and one possible case for which they are still awaiting the test results. The latter unfortunately had to be humanely euthanised.
He says, however, that only one horse has tested positive and died of the WNV in the area.
"One horse died due to the West Nile virus and one horse was put to sleep due to a possible positive EHV-1 result. I have personally treated two positvie EHV-1 cases which survived and one abortion due to the virus. The challenge we as veterinarians are facing is that the test results take 14 days to come back - therefore when symptoms start showing we have to be pro-active with treatment," he says.
Since EHV-1 is a virus, antibiotics will have no effect and antiviral drugs have shown minimal effect in already affected horses. Treatment is primarily supportive, and usually includes anti-inflammatories and fluids to maintain hydration. Slings may be used to help horses that are unable to stand on their own.
"I strongly urge all horse owners and livery yards to make sure their animals are vaccinated against these viruses," said Truter.
According to Dr Henk Basson of the Dana Bay Veterinary Clinic, WNV is suspected to be carried and spread by wild birds and is not transmitted from horse to horse.
The EHV-1 virus however is transmitted directly from horse to horse as close as five meters. "It can also be transmitted by contaminated equipment, clothing and vehicles. It is highly contagious and most horses will only get mild symptoms but remain contagious for a long time. Foals are particularly susceptible and can become very ill," he said.
West Nile virus
The WNV is a mosquito-transmitted virus that first appeared in 1937 in Uganda. It circulates between birds as replication host, usually without causing disease. The mosquito that transmits WNV in Africa belongs to the Culex genus and is found in the vicinity of dams or standing water across the continent.
The virus can cause inflammation or swelling of the brain and spinal cord in horses, birds and humans. Clinical signs include fever, depression and sudden death.
Muscle fasciculation (spontaneous, involuntary muscle contraction and relaxation), particularly in the muzzle and neck, cranial nerve dysfunction e.g. facial nerve paralysis, dysphagia (swallowing difficulties), weakness and ataxia are some of the neurological signs that can be expected.
Should your equine show any of the above symptoms or signs, isolate the animal and contact your veterinarian immediately.
Equine herpes virus 1
EHV-1 and -4 are important agents associated with infectious upper respiratory tract disease (IURD). Risks associated with IURD include host, environmental, management and pathogen-specific factors. In addition, higher detection rates of EHV-1 and -4 occur in juvenile horses and during the colder winter months.
Physiological stress is arguably one of the more important risk factors, with associations reported between EHV-1 and -4 shedding and externally derived stressors. Transport and the subsequent confinement, handling and management may contribute to physiological stress.
According to Truter, clinical signs of viral respiratory infections include bilateral serous-mucopurulent nasal discharge, enlarged submandibular lymph nodes, coughing and pyrexia.
The infection can be spread via respiratory droplets in the air, direct horse-to-horse contact and indirectly via people. It can also cause abortion in pregnant mares.
Should you suspect that your horse is infected, isolate the animal immediately and call your veterinarian.
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