Signs of foot and mouth disease: information for vets

General signs of foot and mouth disease

The vesicular lesions in foot and mouth disease are found mainly on the:

• epithelium of the mouth (primarily the tongue, dental pad and gums)
• nostrils
• muzzle
• hooves or claws (primarily interdigital spaces and coronary bands)
• teats and udder
• rumen pillars.

Early lesions are vesicles, which rupture, leaving haemorrhagic granular erosions. The erosions become necrotic and heal from the rims within about 2 weeks.

In young calves that have died suddenly, typical pale focal degeneration of the myocardium is frequently seen (for example, as a tiger heart). In older animals, similar degeneration of heart or skeletal muscle may occasionally be found.

Vesicular diseases with similar signs

Pigs

• Vesicular stomatitis
• Swine vesicular disease
• Vesicular exanthema

Ruminants

• Vesicular stomatitis

All vesicular diseases are exotic and notifiable to MPI. Diagnostic testing by MPI will confirm the identity of the causal virus.

Animal-specific signs

Cattle

• Incubation is about 4 to 6 days, although it can be shorter.
• High temperature (40 to 41 degrees Celsius) in initial stage.
• Severe depression and anorexia.
• Acute, painful stomatitis with smacking of lips and drooling of long, ropey saliva.
• Vesicles on tongue, dental pad, hard palate, gums and buccal mucosa.
• Vesicles contain straw-coloured fluid.
• Vesicles rupture within 24 hours, leaving a raw, painful surface.
• The tongue surface may slough off in patches and heal with loss of papillae.
• Appearance of vesicles on the feet, particularly in interdigital clefts and on the coronet band.
• Marked lameness, idleness or leaning, and painful swelling and blanching of the coronet band and heel bulbs.
• Secondary bacterial infection may lead to severe involvement of deeper structures of the foot.
• Rapid loss of condition and fall in milk yield.
• Vesicles may appear on hairless areas and, if the teat orifice is involved, severe mastitis often follows.
• Young suckling calves may die suddenly, without other signs.
• Symptoms vary in severity and may be quite mild.

Pigs

• Oral lesions are usually small, as are those around the snout.
• Severe lameness may occur due to the involvement of all 4 feet when separation of the keratinised layer of the hoof from the corium occurs.
• Piglets may suffer heavy mortality associated with severe gastroenteritis, pancreatitis and myocarditis.

Sheep, goats, deer, alpaca and llama

• Clinical signs can be inapparent or very mild, requiring very careful examination.
• Erosive or vesicular lesions may be found on the tongue, dental pad, gums, buccal cavity, hard palate and on the coronet band and interdigital space on feet, but are usually less pronounced than in cattle.
• Foot lesions are frequently complicated by secondary bacterial infections, including foot rot.
• Lesions may also occur on the teats, prepuce, vulva and rumenal mucosa.
• In young lambs, muscular necrosis with lesions in the myocardium and, to a lesser extent, in skeletal muscle often leads to rapid death.

General examination process

1. Observe all groups of animals on the property from a distance for lameness, excess salivation, lip smacking and any other abnormal signs.
2. Record rectal temperatures of all affected animals. Observe and record any vesicles or erosions. Try to avoid rupturing any vesicles and fully describe all lesions, noting if they are ruptured or not, their size, depth, peripheral edge (for example, ragged or punched out) and the degree of healing. Take photographs of vesicles and erosions.
3. Examine for species-specific signs as below.
4. Obtain a history of movements of animals, people, vehicles and equipment on and off the property within 3 weeks.
5. Stay on the farm, ask the farmer and staff not to leave the property, and call MPI immediately on 0800 80 99 66.

Species-specific examination for the disease

Cattle

Note any history of sudden illness or drop in milk production. Look for lesions on the muzzle and nares (examine before applying nose grips), mouth, tongue, lips, dental pad, hard palate, gums, cheeks, all feet (cast animal, if necessary, and carefully wash or hose feet), interdigital cleft, coronary band, bulbs of heels, udder and teats, and vulva or prepuce.

Pigs

Severe lameness is the primary clinical sign. Observe the pig walking on hard ground or concrete. Look for lesions on the snout, lips, tongue (usually smaller and less obvious than in cattle) and feet. Look for separation of the hoof at the coronary band and accessory digits, and blanching around the coronet.

Sheep, goat, deer, alpaca and llama

Sudden acute lameness is the primary clinical sign. Look for vesicles or erosions and blanching or swelling on all feet (clip the wool around the coronary band), coronary band, and interdigital space. Look for separation of the hoof and small vesicles or erosions on the dental pad and lips. Alpacas aren't at significant risk from FMD, as they are quite resistant. Contact between camelids such as alpacas and other cloven hoofed animals should be avoided.

Who to contact

Report suspected cases immediately to MPI's pest and disease hotline on 0800 80 99 66.