African Horse Sickness - a Growing Concern

by Alison Grimston

Copyright © 2008 The Naturally Healthy Pet.com

Introduction: African horse sickness is a potentially fatal, untreatable illness of equines, and cases are being found further north with global warming. If a case of this notifiable disease were to be found in the UK, we may find a foot and mouth-type slaughter situation occurring among our equines. Read below for more information!

Aetiology: African horse sickness is caused by an orbivirus, carried by midges. It is endemic in sub-Saharan Africa, and affects horses, mules and donkeys. Zebras appear to be relatively unaffected. Elephants appear to carry the illness subclinically, and dogs can be severely affected, usually from eating infected meat.

Clinical Signs: There are several subtypes of the disease:

Acute Pulmonary Type: This is characterised by fever (temperature >40.5°C, sweating, and severe respiratory signs - coughing, laboured breathing, yellow frothy nasal discharge. There may also be congested mucous membranes, and collapse and death can occur within a few hours. Survivors have severe respiratory distress for several weeks, but there is a 95% mortality.

Subacute Cardiac Form: In this form the heart is more greatly affected. Signs include pericardial effusion (fluid between the muscle and outer covering of the heart), pleural effusion (fluid in lungs, due to heart failure), endocarditis (inflammation in the inner layer of heart muscle, the endocardium), swelling of head, neck & chest (oedema, due to heart failure), and cyanosis (blue colour due to lack of oxygen in the blood) of mucous membranes. petechiae (red specks of blood where it is leaving the smallest blood vessels) may be evident on the mouth and under the tongue. Fever tends to be intermittent, and there is a 60% mortality, from heart failure.

Mixed form: In this there is a cCombination of respiratory followed by cardiac symptoms, and the incubation period is 3-7 days

Chronic febrile type: This is less severe - often subclinical, rarely found in horses as they are so susceptible, more often in donkeys and mules. Signs include fever in the first few days of infection, appetite loss (anorexia), mild cough, and conjunctivitis

Current Western Treatments: It is fundamentally important to seek the urgent opinion of your veterinarian. No active treatment is currently possible, and in the European Union all affected animals will be compulsorily slaughtered. In other areas of the world, supportive nursing care may help. A further possibility is vaccination - 9 subtypes have been isolated, each has its own vaccine; two injections are needed & the effect is relatively short-lived.

Limiting Outbreaks: It is possible that the virus spends part of the year in Africa in subclinically affected, unrecognised hosts, while the midges are inactive. This may be the reason why, to date, outbreaks in Spain have been short-lived. Such outbreaks may have been from importing infected zebras.

Horses imported into the European Union are routinely tested for African horse sickness. EU Council Directive 92/35 provides for compulsory notification of cases, and the setting up of a protection zone of least 100 kilometres radius around any infected premises, to remain in force for at least 12 months.

Complementary Therapies: This is a notifiable disease in the United Kingdom. Many complementary therapies such as healing, Reiki and massage will help with supportive nursing care in cases likely to recover (and in countries where the animals will not be put down). Also remember how useful healing and Reiki can be when an animal does have to be put down, both for easing its passing & helping the owner.

Conclusion: This devastating illness is too infectious for affected animals to be allowed to survive, at least in the European Union. It may spread North from Africa with global warming, and a few cases have been seen in Spain. In the UK, if a case was to be found, the management is likely to be similar to that of Foot and Mouth Disease.