Viral and Fungal diseases

Viral infections in horses are common and range from mild respiratory issues to severe fatal diseases. Equine fungal diseases (mycoses) range from common to superficial skin issues and can affect skin, hooves, respiratory tract and internal organs. They thrive in damp anaerobic environments.

Equine Influenza

Equine influenza is a virus which is highly contagious and can transmit through direct contact. This means that it can be caught from the air and from cough and sneeze particles. It affects the respiratory system. Horses will either ingest or inhale it.

The symptoms of equine flu are a high temperature, cough, discoloured and increased nasal discharge, lethargy, difficulty breathing, impacted performance level and loss of appetite.

Influenza doesn’t have a cure but an infected horse should be given fluids, mashes, change of forage (soak or haylage), nutrients, rest, supplements, electrolytes, low dust environment and Bute.

To prevent equine influenza the horse should have regular temperature checks and health checks, isolate infected horses, quarantine new horses, vaccinate and use good biosecurity measures.

Equine Herpes Virus

There are three different types of EHV. EHV3, EHV1 and EHV4. EHV3 is a venereal disease which is sexually transmitted. It causes bumps and warts and can test for it using a swab on the genitals.

EHV1 is a virus which causes abortion, respiratory disease and occasionally neonatal mortality. It is spread due to direct contact, contaminated equipment, respiratory secretions within a stable and on the yard can spread it too. Aborted foals and afterbirth may also contain the virus. It can affect the neurological system.

EHV4 causes rhinopneumonitis. It is the most important viral cause of respiratory infection in foals and causes lifelong latent infection in affected animals. It causes fever, loss of appetite and discharge from the nose. There can be swollen glands, cough lethargy and a high temperature. Vets can test for it using a swab or a blood test.

Can also cause hind limb weakness, lessen ability to stand, loss of tail bone and the horse may become unable to pass droppings or urinate.

There is no treatment and supportive care will be needed such as Bute, rest, clean environment and mashes to increase appetite.

Pregnant mares should be vaccinated against it at 5,7 and 9 months of pregnancy. Stallions should be tested and may be put down if positive.

Equine Viral Arteritis

EVA is a virus caused by Alphaarterivirus Equid. It is a notifiable disease which means that it must be reported to DEFRA. There is significant impact on breeders, racing and show horses. It is spread by direct transmission, bodily fluids, contact with aborted foetus or fluids and airborne droplets.

The symptoms of EVA are fever, lethargy, depression, swelling of the lower legs and genitals, conjunctivitis and swelling around the eye socket, nasal discharge, hives, decreased fertility, abortions and loss of appetite.

There can be cases of asymptomatic carrier stallions which means they have no symptoms but can spread the disease. It is diagnosed by viral isolation or serology (ELISA) however does not differentiate between vaccination or infection.

Treatment and management include supportive care for adult horses but foals are usually put to sleep. Antipyretic which reduces fever, anti inflammatory like Bute, diuretics which increase excretion and rest. Castration for carrier stallions to eliminate the virus. Cold hose and ice swollen legs. Feed haylage and electrolytes. Dark stables. Avoid over rigging and have good ventilation. Use dust free bedding and clean away any discharge to avoid reinfection.

Prevention includes biosecurity measures and good management of breeding populations with testing and isolation. Vaccinate colts and stallions which involves a single dose which can be up to £240 plus the vet visit. Prior to vaccination the stallion will need to be tested to see if he has antibodies. They take another sample day of vaccination and record in his passport. They have two T weeks apart and then boosters every 6 months. It is called Artevac.

Thrush

Thrush is a fungal disease but can also be cause by an anaerobic bacteria. It commonly affects the central sulcus (groove) in the foot, the spreading to the collateral sulcus and the main section of the frog.

Contributing factors include, deep clefs, imbalanced feet, wet, muddy, standing, not picking out feet, limited movement and can affect one or more feet.

Symptoms include a foul, unpleasant colour from the hoof, a black or dark discharge and a soft, spongy frog. As well as, fissures or deep pockets in the frog, lameness, sensitivity to pressure from the hoof pick and bleeding.

Treatment and management includes professional cleaning and debridment of the hoof by a farrier to remove all dead tissue and allow air to reach the affected area. Follow with daily cleaning and the application of a topical antiseptic or commercial thrush treatment. This includes iodine. The horses hooves should be kept dry, hooves picked out regularly, excessive and regular farrier visits.

Ringworm

Ringworm is a highly contagious fungal disease of the skin. It is characterised by circular patches of hair loss that can be crusty, scaly or inflamed. It is a zoonotic disease so can spread to humans.

Symptoms include circular crusty patches of hair loss, itchiness, swelling and redness or even bleeding of the skin.

Ringworm is caused by fungi, primarily from the Microsporum and Trichopyton species. It can spread through direct contact or indirectly through contaminated items like shared equipment, grooming brushes and bedding.

Treatment includes consulting a vet, topical antifungal solutions or washes, applying treatments with gloves and avoiding rinsing and oral medication in severe cases.

Prevention involves keeping the horses environment clean and dry, isolating contaminated horses and avoiding contact with them. Disinfecting everything and wash hands. Lastly, use as little wood as possible as it can live in wood for a long time.