Categories Of Diseases in Poultry
"last update: 26 June 2024"
- Category 2 Diseases
Disease | Cause | Ages affected | Species | Mortality | Signs and Symptoms | Pathognomonic lesions | Control |
Newcastle Disease (lentogenic or mesogenic) | Virus | All | Most domestic birds | Low, except in very young birds where mortality may reach 20% | Signs may vary by species. There may be no signs in waterfowl. Respiratory: sneezing, coughing, difficulty breathing Nervous: twisted necks Reproductive: decreased egg numbers | Mild conjunctivitis and tracheitis are observed. Recovered flocks show septicemia and air-sacculitis due to secondary infection with E. coli | Vaccination, biosecurity |
Low Pathogenicity Avian Influenza (LPAI) | Virus | All | Most domestic birds | Usually, < 5% but may be up to 60% in turkeys. | Signs vary by species and infecting virus. There may be no signs in waterfowl. Respiratory: sneezing, coughing, wheezing Reproductive: decreased egg numbers | tracheitis, pulmonary edema and if secondary bacterial infection occurs, air-sacculitis is observed. | Biosecurity, depopulation, (vaccination)
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Infectious laryngotracheitis (ILTV) | Virus | All but mostly in adults | Chickens | Usually 10-20% but may be very mild < 2% mortality or very severe > 50% mortality | Respiratory: nasal discharge, difficulty breathing, coughing, bloody mucus Reproductive: decreased egg numbers. | severe hemorrhagic tracheitis with the presence of blood clots which may obstruct the glottis resulting in asphyxiation. | Vaccination, biosecurity |
Infectious bronchitis virus | Virus | All but most severe in chicks | Chickens | 0-25% | Birds may be depressed with ruffled feathers. Respiratory; gasping, coughing, sneezing, wet eyes Reproductive: thin-shelled, rough and misshapen eggs, decreased egg numbers | Hyperemia of the trachea and accumulation of mucus in the nasal cavity | Vaccination, medication for secondary bacteria |
Marek's Disease | Virus | Usually, 3-30 weeks of age | Chickens | 0-30% in unvaccinated flocks | Unthriftiness, failure to gain weight. Nervous: paralyzed in one or both legs or wings, difficulty stanning pale eyes. | Unilateral enlargement of nerves of the sciatic plexus | Vaccination |
Avian Leukosis | Virus | > 30 weeks of age | Chickens | Usually, < 3% although it may exceed 20% in some cases | Unthriftiness, weight loss, enlarged abdomen Reproductive: decreased egg numbers | Internal organs contain white or grey nodules which are cancerous lymphoid tissue that has spread from the bird’s bursa. | Chicks from clean flocks, biosecurity |
Duck virus hepatitis | Virus | Young, < 6 weeks | Ducks | Close to 100% in ducklings 1< wk. old. 50% in 1-3 wk. old, very low in > 4 wk. old | Death may be the first sign of disease. Nervous: birds fall on their sides, kicking | enlargement of the liver with punctate or ecchymotic hemorrhages | Isolation of young ducks, (vaccination) |
infectious bursal disease | Virus | Mostly 3-6 weeks | Chickens | Usually 0-25% but in some cases, may be up to 100% | Prostration and death Digestive: vent picking, soiled vent feathers, whitish or watery diarrhea | Dehydration and muscular hemorrhages, In acute cases the characteristic lesion comprises enlargement of the bursa of Fabricius | Vaccination, biosecurity |
Avian Encephalornye-litis | Virus | Mostly 1-3 weeks | Chickens | May reach 50% in young birds | Nervous: difficulty walking, paralysis, tremors | No gross lesions are observed, Incoordination and lateral recumbency | Vaccination |
Fowl pox | Virus | All, except newly-hatched | Chickens, turkeys | < 5% in skin form; 10-50% in respiratory form. | Poor weight gain. Skin: scabby, raised pocks on the face Digestive: loss of appetite Respiratory: nasal discharge, difficulty breathing | Pink focal lesions occur on the comb and wattles and non-feathered portions of the body | Vaccination, biosecurity |
Fowl cholera | Bacteria | Birds >4 weeks are most susceptible | Chickens, ducks, geese, most birds | 10-90% mortality. Mortality is highest in turkeys, ducks. | Death may be the first sign of disease. Respiratory: Gaping, difficulty breathing Digestive: diarrhea, especially in ducks | enlargement of the spleen and liver with punctate hemorrhages of the viscera including the heart | Medication, remove reservoirs, vaccination |
Omphalitis | Bacteria | Birds less than 2 weeks old | Any | Variable.( May reach 100% ) | Late incubation mortality. Navel is inflamed and the abdomen is distended. | Enlarged yellow yolk-sac, typical of omphalitis in a 3 day old chick. | Medication, hatchery sanitation |
Mycoplasmosis | Bacteria | All | Chickens, pigeons, turkeys | Very low. | Respiratory: facial swelling, nasal discharge, coughing, foamy eyes Reproductive: Decreased egg numbers, decreased hatchability Skeletal: joint swelling. | Acute foamy Caseous air-sacculitis | Vaccination, biosecurity |
Chlamydiosis | Bacteria | All | Ducks, pigeons, turkeys | Variable, but severe cases may have 5-30% morality | Depression, weakness. Nervous (young ducks): trembling. Imbalanced gait Respiratory: swollen eyelids, nasal discharge, difficulty breathing Digestive (young ducks): yellow-green diarrhea. | Fibrinous pericarditis and perihepatitis, Hepatomegaly and splenomegaly, air-sacculitis | Medication, biosecurity |
Infectious Coryza | Bacteria | All, disease most severe in mature birds | Chickens | Rapid onset and high mortality. | Respiratory: Facial swelling, especially around the eyes, nasal discharge, rales. Digestive: loss of appetite, sometimes diarrhea. Reproductive: decreased egg numbers | Severe conjunctivitis and inflammation of the periorbital fascia. Chronic cases show serous to caseous sinusitis. | Vaccination, remove reservoirs, biosecurity. |
Trichomoniasis | Protozoa | Young birds | Pigeons | Can be up to 50% without treatment | Young birds lose weight and may die. Digestive: thick, yellow areas inside the mouth, difficulty closing mouth |
| Sanitation, medication |
Coccidiosis | Protozoa | Young birds, older birds become immune | Most although the coccidian of one species do not infest other birds | Variable depending on how severe the case is and the type of coccidian | Depression, weakness, decreased weight gain, dehydration. Digestive: may have mucoid or bloody diarrhea. | Hemorrhage interspersed with white foci visible through mucosa | Self-immunization, medication |
Histomoniasis | Protozoa | Turkeys: 3-12 weeks. Chickens: 4-6 weeks | Turkeys, chickens | Mortality is generally low in chickens <30% but higher in turkeys (up to 70% | Depression, weakness Digestive: loss of appetite, yellow feces in turkeys, blooding droppings from chickens | thickening of caecal mucosa, petechial haemorrhages, and hepatic granulomas | Medication, put birds on wire or cement |
