Infectious diseases

IN THIS SERIES, WE’RE COVERING DISEASES THAT CAN AFFECT THE EQUINE POPULATION; HOW TO SPOT THEM, MEASURES TO TAKE TO PROTECT HORSES IN YOUR CARE, AND HOW TO PREVENT TRANSMISSION. IN PART FIVE WE TALK ABOUT THREE CONTAGIOUS DISEASES SEEN SPECIFICALLY IN FOALS AND WEANLINGS.

Foals are born with poorly developed immune systems because antibodies cannot cross the equine placenta. Early disease protection is reliant on the transfer of antibodies from the mare via the colostrum or fi rst milk. The foal’s gut is only able to absorb these antibodies in the fi rst 12 hours from foaling, which is why it’s vital foals suckle soon after birth. Failure to do so makes the foal more susceptible to potentially fatal infections in the fi rst weeks of life. The condition of a sick foal can deteriorate quickly so it’s important that any illness is promptly investigated and treated by your vet.

Equine Rotavirus damages the lining of the intestines, inhibiting digestion and absorption of food. It’s one of the most common causes of diarrhoea in foals. Signs: Diarrhoea, reluctance to nurse, lethargy, fever, collapse. Younger foals generally show more symptoms. Age aff ected: From three days to fi ve months. Incubation period: Three to ten days. Transmission: Via ingestion of contaminated droppings or dust. Highly contagious, high levels of virus in the faeces of infected animals. Diagnosis: Faecal sample to detect virus. Treatment: Primarily supportive - IV fl uids, gastrointestinal protectants and probiotics. Prognosis: Early detection nd treatment often leads to rapid recovery. Prevention: Vaccination of pregnant mares to improve foal immunity via antibodies in colostrum. Aff ected foals should be isolated, with strict biosecurity measures put in place.

Rhodoccocus equi is the bacterial culprit of this form of pneumonia – the most serious and life –threatening pneumonia seen in young foals. Signs: Failure to thrive, diarrhoea, pneumonia, fever, lethargy, poor appetite, cough and rapid breathing with nostril fl are and increased eff ort. Joint infection and eye problems may also be seen. Age aff ected: Between three and 2 weeks, four months being most common. Incubation period: Three to four weeks. Transmission: Ingestion of bacteria from infected faeces and contaminated fi elds or yards. Diagnosis: Isolation of the organism from fl uid obtained by tracheobronchial aspiration TBA , along with detection of abscesses in the lungs. Treatment: Includes specifi c antibiotics given for three to 12 weeks. Prognosis: The survival rate is approximately 70%-90% with appropriate therapy. Prevention: Aff ected foals should be isolated. Early screening for the bacteria is recommended at locations with known problems. Reducing stock levels, removing droppings from paddocks and limiting airborne dust levels may help reduce incidence.

Commonly known as Lawsonia disease, Equine Proliferative Enteropathy (EPE) is a disease of the small intestine caused by the bacterium, Lawsonia intracellularis. Signs: Lethargy, poor appetite, weight loss, fever, diarrhoea, colic, fl uid swelling of the limbs, sheath and under the belly. Aff ected foals may not show signs other than a failure to grow and gain weight normally. Age aff ected: Most common between two and eight months but usually following weaning. Incubation period: Two to three weeks. Transmission: Ingestion of bacteria from faeces. Seen in many species including rodents, rabbits, cats and dogs. Transmission between species is by contamination of paddocks, feed and bedding. Diagnosis: Identifi cation of thickened loops of the intestines on ultrasound scan. Identifi cation of the bacteria in faeces. Blood test for antibodies. Treatment: Includes antibiotics and supportive care. Prognosis: Foals that are treated aggressively usually survive the infection however, these foals may take months to ‘catch up’ in body condition. Prevention: Aff ected foals should be isolated to reduce environmental contamination. Good pest control. Prevent wild/ domestic animals’ access to feed and bedding.