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Appendix C: Disease recognition and control

Anthrax (Bacillus anthracis)

The disease is caused by a spore which can live in the soil for many years. It is ingested in pasture, feed, or water. It may also be transmitted into a wound from brush, fertilizer or contact with another animal (rubbing; wound to wound contact), or through fly or mosquito bites. Incubation is 1-5 days. All warm-blooded animals and humans are susceptible.

Symptoms: High fever, prostration, colic, diarrhea, increased heartbeat and respiration, swellings around the throat, blood in milk, urine or mucus; upon death, lack of rigor mortis, enlarged spleen, liver, and kidneys.

Treatment: Early administration of massive doses of penicillin sometimes effective.

Prevention: Rotate pastures; spray animals with fly repellents. Nine types of serums, bacterins and vaccines are now available. There may be veterinary intervention according to the area. Quarantine infected herds.

Remarks: Carcasses and contaminated materials should be buried at a minimum depth of two meters. A disease of lower animals that is transmissible to humans.

Brucellosis (Bang's disease, undulant fever)

An infectious disease which causes pregnant heifers and cows to abort the fetus, retain afterbirth, or develop uterine infections. The bacteria are transmitted through ingestion of feed or bedding, or through licking of wounds, vaginal discharge or aborted fetus. Also affects sheep, goats, swine, horses and humans with varying symptoms and results.

Symptoms (in cattle): Aborted fetus (7-8 months); relaxed placenta, enlargement of joints and testicles, sterility, uterine infection, reduced conception rate.

Treatment: French vaccines are in experimental stage.

Prevention: Vaccinate calves 2-10 months old in areas where disease is present. Slaughter infected animals.

Remarks: The meat of slaughtered animals may be consumed if cooked. Pasteurization kills the bacteria in contaminated milk.

Blackleg (Blackquarter)

A highly infectious and fatal disease affecting cattle and sheep. Young animals are particularly susceptible; older animals develop some natural immunity. The disease often occurs regularly in the same herds and localities. The bacteria lives in the soil; it is ingested or enters the body through a wound and then spreads through the herd by way of contaminated feed (saliva or other secretions from the infected animal carry the bacteria). Incubation 1-5 days.

Symptoms: Lameness, swellings in joints, back, loin, and hindquarters (these are gasfilled lumps which crackle when pressed). Also: fever, loss of appetite, rapid breathing, depression. Death in two days after onset of symptoms.

Treatment: Massive doses of antibiotics in early stages of disease.

Prevention: Immunization of calves 1-4 months old. Afterwards, these animals are vaccinated every 6-12 months until three years of age.

Remarks: Burn and bury carcasses; the disease does not affect humans, but the meat should not be consumed.

Contagious Bovine Pleuropneumonia

This is a chronic respiratory disease which causes the lungs of the infected animal to fill with liquid.

Symptoms: Chronic cough, diminished appetite evidenced by irregular grazing habits. Affected animal may be too weak to move with the herd. Elevated temperature. Discharges may contain pus, blood, or be of unusually strong odor. Pinching of nostrils will induce a short, dry cough.

Treatment: No known treatment.

Prevention: Annual vaccination.

Remarks: Cured animals which have been infected with this disease do not make good draft animals. Lesions in the lungs (damaged tissues) make the animal short-winded.

Pasteurellosis (Shipping fever; sometimes called "Hemorrhagic Septicemia", but this is considered a misnomer.

The disease is caused by viruses and/or bacteria commonly present in the lungs or mucous membranes of cattle, horses and other animals. Strains vary in their ability to cause disease, but animals under stressful conditions (shipping, transfer to new environment) are particularly susceptible. Exposure, overcrowding, physical tension, improper feeding lower the resistance of the infected animal and increase the presence and strength of the micro-organism. Incubation 2-10 days.

Symptoms: Diarrhea, loss of appetite, variable high temperature, difficult breathing, prostration, discharge from eyes and nose, swelling in neck region. Can kill in 2-3 days.

Treatment: Isolation of infected animal; use of antibiotics and/or sulfonamides.

Prevention: Annual vaccination; good management and feeding.

Remarks: Newly acquired draft animals should not be trained, castrated, or dehorned in the days following transfer. Use of animals which have been infected and recovered from the disease may be uneconomical to use due to lesions on the lungs.

Rinderpest (Cattle plague)

A highly contagious virus affecting cattle. Three forms are known, two of which result in very rapid death and one which is chronic. Transmission of the disease is primarily through ingestion of contaminated food or water. Incubation 3-6 days.

Symptoms: Fever, poor appetite (slow emaciation of chronically affected animals), dehydration due to diarrhea, discharge from nose and eyes, salivation, swelling and closing of eyes. Lips, muzzle, vaginal membranes bear white spots inside a raw ring 1/2 cm wide.

Treatment: No known treatment.

Prevention: Annual vaccination; life-long effective vaccine now available.

Tetanus (Lockjaw)

This is a highly fatal disease which is usually the result of an infected wound. Bacterial infection causes the release of powerful poisons into the bloodstream. Horses and donkeys are particularly susceptible, but ruminants, swine, and humans also are affected. Incubation: one week to several months.

Symptoms: Increasing stiffness of the head and neck with accompanying difficulty during chewing and swallowing. The inner eyelid draws over the eye. After 24 hours, the animal shows extreme sensitivity to noise, becoming excitable and frightened. Spasms occur in the neck and back, the head and neck extend. The animal will not lie down, remaining standing until close to death.

Treatment: Tetanus antitoxin administered immediately after appearance of first symptoms.

Prevention: Immunization with antitoxin and annual booster. Proper disinfection of all wounds.

 

Parasites and parasitic disease

Parasites are organisms that live at the expense of another organism or "host". Internal parasites live inside the host in blood, muscle, or other body tissue which provides a favorable environment for growth and reproduction. External parasites live on or under the skin, or pierce the skin and feed on the animal's blood. In general, parasites do not kill the host, but cause a chronic state of ill-health which is reflected in low productivity and high susceptibility to other diseases. Young, pregnant, lactating, or malnourished animals are those most seriously affected by parasites.

Helminthiasis

This is a general name for any one of a number of conditions related to the presence of worms in the digestive system. While inside the host animal, they absorb food, interfere with digestion, or reduce the efficiency of blood-forming tissue. Sometimes the worms migrate to other parts of the body. The life cycle is completed when the female lays eggs which are passed out in the feces and which continue to incubate in pasture, manure, bedding, water, or intermediate host. Except in the case of hookworm (see below), the eggs are ingested by the new host (the draft animal) and hatch inside its digestive tract.

Symptoms: Chronic weight loss, variable diarrhea and constipation, weakness, lowering productivity. Other symptoms are specific to the type of worm.

Treatment: Numerous products are available and should be used as recommended by local veterinary or sanitary officials. Commonly used antiworm treatments (anthelmintics) are phenothiazine, thibenzole, and Vadephen. Administration varies from 2-4 times per year according to size and type of animal, and climatic conditions which affect the presence of the particular organism.

Prevention: Rotation of pastures and use of sanitary watering troughs reduces the likelihood that an animal will ingest parasite eggs; good feeding and management coupled with regular administration of anthelmintics (as prescribed).

Remarks: Worms may be classified in three major groups:

ROUNDWORMS

Ascarids affect pigs, cattle, poultry, and especially horses; they are intestinal worms which can impair growth or cause death in young animals. Worms may migrate to lungs and cause damage.

Hookworms are blood-sucking worms which are ingested or which enter the skin and migrate to the intestine, causing gastro-enteritis and anemia in ruminants and pigs.

Strongyles affect horses ant mules, causing anemia, emaciation, colic, and sometimes death. Some species of the worm appear in the feces.

FLUKES are found in all animals, especially those which graze in wet or marshy areas. The liver is damaged and fluids leak into the body cavity, giving the animal a "potbellied" appearance. Ruminants are especially susceptible. The disease is called Distomatosis.

TAPEWORMS primarily affect sheep and goats, but may be present in horses or cattle. Worms in the digestive tract can be very long and rob the animal of nutrients. Worm larvae may live in the bladder or muscle tissue and cause general weakness and lowered productivity.

Mange (Scabies)

Highly contagious skin disease transmitted by mites which burrow under the skin and breed in large numbers. The itching causes the animal to rub, depositing the organism on trees or fences where other animals then contract the disease.

Symptoms: Hair falls out, grey scabs appear, skin thickens and develops folds. Itching is intense and may cause animal to bite or rub itself, causing open lesions. With demodectic mange (present in West Africa), small bumps appear on the shoulder, neck, and trunk.

Treatment: Cut the hair; apply iodine, creosote or mixture of two parts oil, one part kerosene.

Prevention: Isolate infected animals; keep harness, bedding and stable area clean. Spray animal with solution of 0.66X lindane. Burn hair clippings of treated animals.

Remarks: Mange is sometimes classified along with scabies because both are transmitted

by mites and are similar in other respects. It may be noted that Chorioptic Scabies or leg mange is present in West Africa, especially in equine animals.

Ringworm

This fungus grows on the outer layer of skin, causing itching, and, in severe cases, secondary infection due to rubbing. Ringworm is contagious, affecting all animals and humans.

Symptoms: Raised, quarter-sized patches of hair with crusty edge, especially on the ear, nose, eyes, lips, or any area that tends to be moist or humid. The patch becomes raw when the animal rubs or bites it in an attempt to relieve the itching.

Treatment: Cut the hair, remove the scabs with a brush or curry comb; wash with soap and boiled water and apply full strength iodine, creosote, or fungus ointment every 2-3 days.

Prevention: Isolate infected animals; clean and disinfect brushes and tack (harness) regularly; ensure that stable is well-ventilated and sanitary.

Remarks: Fungus diseases are most common during humid seasons, with animals recovering during the dry months.

Ticks

Ticks attach themselves to the skin, burrow, and feed off the animal's blood. They also spread fevers: piroplasmosis, brucellosis, typhus, East Coast Fever, heartwater. Grazing animals are most likely to be affected because ticks cling to tall grass and attach themselves to the passing host (especially during summer months).

Symptoms: Ticks are visible on the underside of the animal and around the ears. The animal kicks up at its belly shakes its head. Eventually it becomes anemic and starts to lose weight.

Treatment: Dab on kerosene, turpentine, or parafin.

Prevention: Regular application of insecticides as recommended by local veterinary service. Sprays or dips can be very effective if done every 57 days; commonly used products include Tigal liquid (mix one part tigal in 800 parts water), Tox (2.5 parts in 1,000 parts water), Gamatox (1 kg in 500 liters water). For ear ticks, use Lindane, Gamatox (mix 1 kg in 500 liters of water), Tox (2.5 parts/1,000 parts water).

Trypanosomiasis

This is a disease caused by parasites called trypanosomes which live in the blood and which are carried by the tsetse fly (glossina), or other biting insects. The disease affects the nervous system, making the animal lethargic and chronically thin; sometimes death results. All animals and humans are affected. Zebu cattle and horses are particularly susceptible. N'dama cattle and some donkeys have a high resistance. The disease is especially prevalent in a band or "vector" which crosses the African continent just north and south of the equator.

Symptoms: Intermittent fever, poor appetite, chronic thinness (especially seen in sunken flanks), swelling of lympth glands, eye mucus and watering, accelerated respiration.

Treatment: No known treatment.

Prevention: For cattle-Vaccination with Ethedium three times yearly, or with Prothedium or Berenil as prescribed. For horses-Vaccination with Trypadine as prescribed.