THE “clinical research” session on epidemiology on the Friday of the BEVA congress began with Dr Alexander Rabitsch of the Office of the Provincial Government of Carinthia, Austria, giving a paper on improving the welfare of horses during transport and the importance of enforcement.
Dr Rabitsch has been awarded the BEVA Trust Equine Transport Enforcement Award, in recognition of the work that he has done since 1998 as an official animal transport inspector.
In Carinthia, all animals being transported are given a pre-loading health check and loading is monitored by the inspectors in accordance with legislation governing intra-Community trade in animals. Also, there is a survey on anything that looks like an animal transport vehicle on all sorts of roads but mainly main roads.
These random checks, where the inspector is backed up by the police, serve to enforce the Austrian law which implements the Regulation (EC) 1/2005. Carinthia, Austria’s most southern province, is crossed by major European animal transport routes. Horses make up only about 1 in 20 or 30 of transports, the remainder involving livestock, pigs, poultry and trout. Among slaughter horse transports, almost none ever comply fully with the Regulation.
Nowadays, all of Austria is checking animal transports and the situation in Carinthia has improved steadily since 1998 when checks found over 60% non-compliance. Non-compliance rates for the whole of Austria were down to 15% in 2010. The negative side of this is that many long-distance transport vehicles used for the trade in slaughter horses from East Europe to Italy detour around Austria, using worse roads and longer journey times, which is a breach of Article 3(a) of the Regulation (EC) 1/2005 which states that, “All necessary arrangements have been made in advance to minimise the length of the journey.”
Even when these are inspected coming back empty through Austria, partitions and provisions for watering the horses are non-compliant: other EU states do not enforce their own regulations. Dr Rabitsch’s mission is to get the European Commission to get all the competent authorities to enforce the legislation that is already in place.
Many approvals should be withdrawn, loading densities should be reduced and detours banned. He believes that the “3Rs” principle which applies to animals used in experiments should be extended to cover animals which are being transported.
The 3Rs are: refinement; reduction (which could be achieved by balanced self-sufficiency in meat and slaughter at the point of production); and replacement (meat could be transported rather than live animals).
Dr Rabitsch observed that truthful labelling of meat products would help too. In conclusion, he said that until the existing law is enforced uniformly throughout the EU, animals in transit will continue to suffer.
In Friday morning’s session on “medical emergencies”, Thomas Divers of Cornell University described his approach to “acute neurological diseases”.
Equine herpesvirus-1 (EHV-1) causes several different clinical syndromes. It may appear as an outbreak, brought in by a horse that is clinically affected. The carrier state is common but seems not to be involved in disease spread.
Virus transmission is mostly horse to horse by way of virus-laden nasal secretions or by an aborted foetus, placenta or foetal fluids. The virus does not persist in the environment. If the infected horse has high levels of virus this may reach the endothelial cells of the central nervous system and cause acute CNS disease.
EHV-1 myelitis is an acute emergency both for the individual horse and its contacts. Biosecurity needs to be put in place and owners notified immediately. Usually, morbidity is moderate and mortality low. However, the neuropathic strain of EHV-1 is increasing in the United States where 83% of outbreaks of acute neurological disease are associated with a mutation in the polymerase gene in the virus which leads to CNS vasculitis.
The resultant myelopathy presents initially as biphasic fever, posterior ataxia and dysuria with increased anal tone and sometimes oedema of the limbs and nasal discharge. Outbreaks are usually associated with bringing a new horse into the stables; three to five days of isolation and temperature-taking of horses returning from events is a good precaution.
Regular vaccination may add to the defences, reducing the morbidity of the neuropathic strain. Strict biosecurity needs to be adopted as maximum virus shedding has occurred three or four days before neurological symptoms develop and continues through the acute EHM.
Initial treatment consists of moderate to high doses of dexamethasone if the disease is progressing, aspirin and/or clopidogrel and valacyclovir which is anti-viral. Bladder catherisation needs to be reinforced by giving antibiotics and the horse needs good supportive care.
If the disease process involves a radiating infarct in the spinal cord, the horse will not recover and horses that become recumbent rarely return to athletic function. The horse may become chronically dysuric and incontinent.
Temporohyoid osteoarthropathy (THO) is another neurological condition that presents acutely. It is a degenerative arthritis of the temporohyoid joint which occurs sporadically in middle-aged horses (mostly five- to 15-years-old).
It is often associated with cribbing, the aetiology is unknown, and the disease is bilateral in 40% of cases though the clinical signs are usually unilateral. Some horses show pain when eating or being ridden.
Acute nerve damage occurs when bony fragments are pulled off the joint, often after a sudden head movement. The fracture involves cranial nerves 7 and 8 leading to vestibular and facial signs with base wide stance. The horse remains bright and alert.
Diagnosis involves clinical signs, endoscopy of the guttural pouch, radiographs or computer tomography. Cerebrospinal fluid shows inflammation, rarely sepsis.
Treatment aims to reduce inflammation and infection and to prevent complications. Because the horse cannot blink, it is at risk of developing exposure keratitis: split lid tarsorraphy to close the eyelids can pre-empt this problem.
About half the horses involved return to athletic use, recovering in about three months, though the facial nerve function can take up to 18 months to resolve. Ceratohyoidectomy is recommended to relieve pain and prevent further fractures of the fused TH joints.
Acute trauma to the CNS accounts for 2.5% of deaths in racehorses. Poor prognosis is associated with prolonged recumbency and fracture of the basilar bones. Foals are often kicked on the head, often resulting in a skin wound, a fractured frontal bone with displaced fragments, haemorrhage which has the potential to become infected and develop into an abscess and brain damage.
Such cases must be stabled and re- examined 24 hours later. Treatment is needed to decrease intracranial pressure, decrease inflammation, maintain perfusion and prevent infection.