The major problems of livestock production are the control of diseases and parasites. It is evident that some animals are genetically resistant or susceptible to diseases and parasites. Since the inception of animal domestication, diseases and parasites have been causing economic losses in livestock production.
The losses due to diseases and parasitic infestations go beyond the death of animals but also reduce the value of the survivors.
Diseases and Parasites of Poultry Animals
Some common poultry diseases are as follows:
1. Adenovirus (or Egg Drop Syndrome)
Cause: Virus
Symptom: Nothing externally obvious, but layers fail to peak, may lose appetite and/or have diarrhea. Eggs lose shell pigment; many are soft-shelled or shell-less.
Post mortem: –
Prevention: Vaccine recently developed (Vaccination).
2. Avian Encephalomyelitis
Cause: Virus
Symptom: Affects chicks up to about four weeks of age, unsteady on feet, tremors in head and/or throughout the body, lethargy, low appetite, sharp drop in production.
Post mortem: No change (may have brain lesions).
Prevention: Vaccinate breeders before production.
Treatment: None.
3. Avian Bumblefoot
Cause: Virus (egg-transmitted)
Symptom: Bull-like swelling of the foot, lameness, foot inflamed.
Post mortem: –
Prevention: Check litter (should be 6 inches deep) and roosts; ensure jagged projections are nailed down. Most edges should be rounded off and free of splinters.
Treatment: Advised only for valuable stock. Open swelling with a sharp sterile knife and press out pus. Wash with antiseptic and apply iodine or sulpha ointment. Confine the bird to a small pen.
4. Avian Infectious Bursitis (Gumboro Disease)
Cause: Viral infection of the bursa of Fabricius.
Symptom: Droopy, ruffled feathers, chalky diarrhea, vent pecking.
Post mortem: Pale, sometimes enlarged kidneys, enlarged bursa.
Prevention: Vaccinate at 21–24 days, depending on antibody status.
Treatment: Maintain good management, keep birds comfortable, and stimulate appetite.
5. Avian Fowl Pox
Cause: Filterable virus.
Symptom: Two forms: skin type shows as wart-like lesions on the comb, wattles, and legs; diphtheritic type causes discharge from nostrils, cheesy membrane in the mouth, and suffocation. Death rate may be high.
Post mortem: May have necrotic lesions on the throat.
Prevention: Vaccination.
Treatment: Remove necrotic membrane if present in the mouth and/or larynx. Add vitamins to water.
6. Avian Newcastle Disease
Cause: Virus.
Symptom: Gasping, wheezing, paralysis, and twisted necks. Severe drop in egg production, soft-shelled eggs.
Post mortem: Mucus in the trachea and thickened air sacs containing yellow exudates.
Prevention: Vaccination.
Treatment: Keep birds comfortable and stimulate appetite. No specific treatment.
7. Avian Laryngotracheitis
Cause: Virus.
Symptom: Coughing, gasping, difficult breathing, bird on keel extending neck during inhalation, soft-shelled eggs, bloody mucus on the floor or wall.
Post mortem: Blood-stained mucus in the trachea (may become necrotic cast in later stages).
Prevention: Vaccination.
Treatment: Keep birds comfortable and stimulate appetite.
8. Avian Marek’s Disease (Range Paralysis)
Cause: Herpes virus.
Symptom: Loss of weight, paralysis of legs or wings, and sudden death. May occur as early as 5–8 weeks of age.
Post mortem: Tumors or enlargement of the liver, spleen, kidney, ovary, testicles, and nerves of wings and legs; lesions in young birds.
Prevention: Vaccination.
Treatment: None.
9. Avian Lymphoid Leucosis
Cause: Virus.
Symptom: Loss of weight, usually in older birds.
Post mortem: Enlarged tumors on the liver and spleen.
Prevention: Raising young birds away from adult stock may help.
Treatment: None.
10. Avian Blue Comb (Mud Fever)
Cause: Virus.
Symptom: Increased thirst, loss of appetite, diarrhea, severe drop in egg production, signs of dehydration.
Post mortem: Watery intestinal contents.
Prevention: Sanitation.
Treatment: Medication according to directions; provide water with molasses at the rate of 1 pint per 5 gallons for 8 hours.
11. Avian Pullorum (White Diarrhea)
Cause: Bacteria.
Symptom: Young birds are sleepy, inactive, pasted up, and have high mortality.
Post mortem: Unabsorbed egg lesions on lungs, liver, and intestines.
Prevention: Eggs from disease-free breeders hatched in disease-free incubators.
Treatment: Feed medication with furazolidone for 10 days or water medication with furazolidone for 7–10 days.
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12. Avian Fowl Typhoid
Cause: Bacteria (Salmonella gallinarum).
Symptom: Inactivity, greenish diarrhea, dehydration, fever.
Post mortem: Liver swollen and dark; spleen enlarged; liver may have necrotic lesions.
Prevention: Only eggs from disease-free breeders should be hatched.
Treatment: Furazolidone either in feed or water for 10 days.
13. Avian Fowl Cholera
Cause: Bacteria (Pasteurella multocida).
Symptom: Fever, dark head, white to greenish droppings, sudden deaths.
Post mortem: Enlarged, cooked liver; hemorrhages in the heart and other organs.
Prevention: Sanitation, disposal of sick birds, isolation, vaccine.
Treatment: Medication according to directions.
14. Avian Mycosis (Pendulous Crop)
Cause: Fungus (Candida albicans)
Symptom: Crop distention.
Post mortem: Cheesy material on crop lining.
Prevention: Sanitation, do not crowd.
Treatment: Fungicidal medication in feed or water according to directions.
15. Avian Thrush (Moniliasis or Sour Crop)
Cause: Fungus (Candida albicans).
Symptom: Affected birds grow poorly, depressed emaciation, foul-smelling discharge from the mouth, loss of appetite and weight.
Post mortem: Mucosa of the crop is thickened with whitish circular ulcers. Crop contents are watery and foul-smelling.
Prevention: Practice sound hygiene and management, avoid overcrowding.
Treatment: Probably best to cull affected birds and apply thorough hygiene measures, but copper sulphate can be tried in drinking water every other day for a week–10 days.
16. Avian Aspergillosis (Brooder Pneumonia)
Cause: Mold/fungus.
Symptom: Fever, difficult breathing, nervous signs, mortality in poultry, especially young birds. (Also dangerous to human beings.)
Post mortem: Nodules in lungs and air sacs, exudates in air sacs.
Prevention: Avoid moist and moldy litter and feed, provide proper ventilation.
Treatment: None.
17. Avian Coccidiosis
Cause: Parasitic Protozoa.
Symptom: Pale comb and wattles, bloody droppings and diarrhea, hunching, emaciation, and death sometimes at a high rate.
Post mortem: Intestinal wall thickened with whitish or reddish areas; cecal type may cause cecal sores with blood.
Prevention: Complete control is difficult on litter, but continuous use of LSF feeds with COXISTAC minimizes outbreaks. Keep litter dry and soft, and apply good sanitation measures.
Treatment: Anti-coccidial drugs usually administered in water.
18. Avian Perosis (Slipped Tendon)
Cause: Manganese or choline deficiency.
Symptom: Swollen hock joints, deformed legs, tendons slipping away from joints, birds hobble on hocks. Many birds affected at once.
Post mortem: –
Prevention: Balanced ration with adequate levels of manganese, choline, folic acid, and vitamin B12. Feed livestock feed rations always.
Treatment: Same as prevention.
19. Avian Spirochaetosis
Cause: Blood parasite (Borrelia anserina).
Symptom: Marked increase in temperature, increased thirst, stands in a crouched position, yellowish-green diarrhea, increased amount of urates in droppings, mortality can be high.
Post mortem: Spleen enlarged, pale, and mottled; hemorrhagic areas in the spleen; enlarged heart, liver, kidneys; catarrhal inflammation of intestines.
Prevention: Vaccination with killed organism (spirochaetosis).
Treatment: Destroy ticks with pesticides. Apply penicillin either by injection or in drinking water.
20. Avian Synovitis
Cause: Bacteria or mycoplasma.
Symptom: Birds lose weight and avoid walking. Hock joints and feet swell and are hot to touch. Affects a limited number of the flock.
Post mortem: In early cases, the spleen is enlarged. The liver is enlarged, mottled, greenish, or dark in color.
Prevention: –
Treatment: Treatment of bacterial synovitis is possible with antibacterial medication but is only recommended for large-scale outbreaks. Where M. synoviae is isolated, breeding birds may be treated with chlortetracycline in the feed, and hatching eggs dipped.
21. Avian Fowl Cholera
Cause: Bacteria (Pasteurella multocida).
Symptom: Fever, dark head, white to greenish droppings, sudden deaths.
Post mortem: Enteritis, mucus in the beak.
Prevention: Do not feed spoiled feed, promptly dispose of dead birds and rodents, avoid wet spots in litter.
Treatment: Flush birds (magnesium sulfate or molasses flush). Clean equipment.
22. Avian Chronic Respiratory Disease (CRD or Air Sac Syndrome)
Cause: Various mycoplasmae (E. coli secondarily).
Symptom: Coughing, gurgling, sneezing, nasal exudates, weight loss, and slow spread.
Post mortem: Mucus in the trachea, air sacs thickened and containing yellow pus, heart sac thickened.
Prevention: Secure mycoplasma-free stock.
Treatment: Medication (antibiotics) in feed or water according to directions.
23. Avian Infectious Sinusitis
Cause: Mycoplasma gallisepticum.
Symptom: Nasal discharge, swollen sinuses, coughing, and labored breathing.
Post mortem: Exudates in sinuses, cheesy material in air sacs.
Prevention: Blood test breeders, secure mycoplasma-free poults. Keep away from chickens.
Treatment: Drain sinuses and inject with antibiotics (early in the disease).
Diseases and Parasites of Pigs
A lot of factors have been known to cause diseases in animals, including pigs. Such factors are poor feeding and management practices, harmful climatic conditions, the activities of micro-organisms such as viruses, rickettsiae, and bacteria, and the harmful effects of parasites, which could either be ecto- or endo-parasites.
Micro-organisms are, in most cases, responsible for the symptoms and courses of diseases that are transmissible from sick to healthy animals (infectious diseases). These organisms are considered as primary invaders, in contrast to certain other species of bacteria that can exert a harmful effect only on an animal whose resistance has already been lowered (secondary infection). Lowering of resistance is brought about by many environmental factors, such as deficient or inadequate rations, but often it is a primary attack by a virus that weakens the animal (lowers its resistance). When the body is in this condition, some types of bacteria that are ordinarily harmless become active and give rise to disease (secondary infection).
This article is not aimed at providing exhaustive information on pig diseases and parasites but rather to serve as a guide for practical health control practices in pig production. The discussion below gives detailed information on the major diseases and parasites of pigs in Nigeria and some other regions, as well as their control measures.
Diseases Caused By Bacteria
1. Swine Erysipelas or Diamond Disease
The disease is caused by the bacterium Erysipelothrix insidiosa. It is known to be very resistant to adverse conditions and could be found even among healthy pigs. An abrupt change in diet or a sudden change in the weather could cause the disease.
The disease exists in the septicaemic, cutaneous, and chronic forms. In the septicaemic form, the symptoms include high fever, a dull appearance, and the skin shows flat red patches. There is difficulty in breathing as a result of oedema of the lungs.
The cutaneous form is usually not very serious and runs a milder course. The animal goes off its food and hides itself in the corners of the pen. Parts of the body have purple or red, diamond-shaped, and clearly demarcated patches, hence the disease is also called diamond disease.
The chronic form of the disease is characterized by un-thriftiness, chronic arthritis, swollen joints, and stiffness, which are first hot and painful, and the animal is lame. Regular vaccination can prevent this disease from occurring.
Animals should be vaccinated before breeding and three weeks before farrowing. Treatment using antibiotics such as penicillin, like FORTECILLIN and TARDOMYOCEL, is effective against the septicemia and cutaneous forms. The disease is transmissible to humans, and adequate care should be taken in managing it.
2. Anthrax or Splenic Fever
A rod-shaped bacterium (Bacillus anthracis) causes this disease. When conditions are unfavourable, the organism forms spores and becomes very resistant, which can only be killed by moist heating at a temperature of 90°C for 45 minutes or 100°C for 10 minutes.
They can survive in the soil for over 24 years. Any animal that dies of anthrax should be burnt, not buried, while the area is disinfected with a 2.5% solution of formaldehyde. Apart from pigs, all animals, including humans, are susceptible. Infection from sick to healthy animals occurs by contact (wounds), inhalation of dust containing anthrax spores, or by insect transmission.
The incubation period is usually 1-3 days and could be chronic in pigs. Signs of infection are high fever and dark mucous membranes, difficulty in breathing, weakness, and swelling in the region of the neck, breast, and genital organs.
There could also be difficulty in swallowing and dripping of dark blood from the body openings such as the mouth, nostrils, anus, and vagina. Infected animals die after a few hours or days of infection. Control is by vaccination using penicillin and oxytetracycline.
It is very important to thoroughly cleanse and disinfect any object or equipment, including clothing, footwear, and exposed parts of the body of the livestock attendant that had contact with a sick animal.
3. Brucellosis (Contagious Abortion)
The organism Brucella suis is the cause of brucellosis in pigs. It survives for a period of up to 2 years in protein-containing animal tissue, such as the remains of afterbirth and on pasture. Sources of infection include afterbirths, fetal fluid, post-parturient vaginal discharges, and milk.
Infection occurs either through the mucous membranes of the conjunctiva and mouth or through some wounds on the skin of animals.
Animals also become infected by feeding on contaminated feeds or water. The disease could be acute, sub-acute, or chronic after an incubation period of at least 14 days and results in temporary or permanent sterility, stillborn, or weak pigs.
Abortion may also result when the sow is 2 or 3 weeks pregnant, while inflammation of the testicles in males may cause sterility. There is no effective treatment for this disease.
Therefore, control and prevention programs of testing and/or disposing of infected animals should be rigid. If many of the breeding animals are affected, it may be wise to replace them with disease-free stock. Brucellosis is a transmissible disease to humans.
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4. Malignant Oedema (Gangrenous Septicaemia Braxy)
This disease is caused by Clostridium septicum, a type of bacterium that multiplies only in the absence of oxygen. It is common in rich humus soils. It forms spores during unfavourable conditions to become resistant, and the spores can only be killed at temperatures above 300°C.
Infection usually occurs during the birth process or through wounds sustained by the animals during fighting, castration, etc. Infection could also occur through the mouth, which is restricted to the digestive canal. The symptoms are fever, loss of appetite, and general weakness of the body.
If the infection is through a wound, an ill-defined swelling will occur. This swelling may spread under the skin and affect the whole of one side of the body and later spread to the neck region. When the swelling is cut, the liquid that escapes gives a rancid odour.
If the infection is through the birth process, the vaginal lips will be swollen, followed by the discharge of greyish mucous membrane.
Fever and diarrhoea will set in later. Treatment is only possible at the early stage of infection. The use of broad-spectrum antibiotics such as penicillin and oxytetracycline is recommended for both treatment and control.
5. Pneumonia and Bronchial Pneumonia
The most dangerous bacteria responsible for this are the Pasteurella. This disease results in inflammatory infections of the respiratory tract. The symptom is difficulty in breathing and a reduction in the volume of air inspired and expired during each breathing movement.
Others include animals having heavy sides complemented with coughs, loss of appetite and weight, which may be followed by death. The disease may be treated with antibiotics, while a simple way of preventing it is to make available a sheltered wooden sleeping area with straw to eliminate cold at night.
6. Cystitis/Nephritis
Cystitis is due to bacterial infection of the bladder and subsequent kidney infection and is particularly prevalent in sows in confined housing.
The disease can be recognised by the presence of pus, and later blood, in the urine. Generally, species of Streptococcus and Corynebacterium are involved, and although large doses of antibiotics can sometimes be beneficial, the disease is usually fatal due to the difficulty of getting the antibiotic to the site of infection.
Antibiotic treatment of the penile sheaths of boars and increasing exercise levels for sows by avoiding close confinement can help prevent the condition.
7. Enteric Colibacillosis
Diarrhoea caused by the bacterium Escherichia coli is the most common cause of death in piglets. E. coli are normal inhabitants of the intestinal tract, particularly the large intestine. Various stress conditions cause these bacteria to multiply rapidly in the small intestine.
They produce toxins, which stimulate a massive fluid loss into the small intestine, leading to scours and dehydration. E. coli scours is primarily a problem in piglets up to 10 days of age. The sows remain healthy, the piglets will continue to suckle, they develop a severe watery diarrhoea, and mortality can be heavy. The infection will spread slowly among newly-born piglets.
The main preventative measure that can be used against E. coli scours is good management, i.e., not allowing for stressful conditions in the piglets which will trigger off scouring. Antibiotics given orally can be effective if given immediately when symptoms are seen.
Vaccines are available which, when given to sows and gilts, help ensure that new-born piglets receive additional antibodies via the colostrum. Gut oedema is another condition caused by E. coli. It affects pigs after weaning, normally between eight and 25kg live weight.
The condition is most prevalent in the fastest-growing pigs, and the typical symptom is oedema in the region of the stomach and intestines. Pigs begin to stagger, and the proportion of animals which are affected will vary considerably.
It is generally believed that stress is the major cause of gut oedema, particularly overeating of high-protein diets. The disease can be contained by reducing feed intake, increasing the fibre level, and lowering the protein content of the ration.
The clinical signs are a raised body temperature and an increased respiration rate accompanied by bouts of coughing. Enzootic pneumonia is a complex condition in which various environmental conditions and stress are involved.
The mycoplasmas are resistant to antibiotics, and the best policy is to try to keep a herd free from the disease. Antibiotic treatment is useful to prevent the occurrence of secondary infections, which can often occur.
8. Greasy Pig Disease (Exudative Epidermitis)
The disease is caused by an infection of the skin with a skin bacterium, Staphylococcus hyicus, and affects pigs from one to seven weeks of age. There is scale formation on the skin, which gives rise to crusts, and the skin becomes greasy with matted hair.
There is no fever, and pigs do not scratch. In the early stages, the condition can be confused with zinc deficiency. There are effective medications for dipping infected pigs, combined with broad-spectrum antibiotic injections.
9. Mastitis-Metritis-Agalactia (MMA Syndrome)
This syndrome is a common problem, which results from bacterial infection in the newly-farrowed sow and may occur as a single entity or any of the three combined. In sows infected with mastitis, the mammary glands become swollen and inflamed, and this may or may not be associated with metritis or agalactia.
The condition can lead to a reduction in milk production, affecting the health of the piglets. Treatment involves the use of antibiotics and anti-inflammatory drugs. Proper hygiene and management practices are essential to prevent the occurrence of MMA syndrome.
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