Poultry Pathogens

Question 1

Aspergillus infection

Answer 1

brooders pneumonia, mycotic pneumonia or pneumomycosis - Cull affected birds

Yellow to grey nodules or plaques in lungs, air sacs, trachea, plaques in peritoneal cavity, may have greenish surface.

Conjunctivitis/keratitis.

Brain lesions may be seen in some birds with nervous signs.

Question 2

Avian Chlamydiosis

Answer 2

Liver necrosis with large, granular basophilic intracytoplasmic inclusions

Carrier commonly by birds

Zoonotic (most commonly from parrots)

Clinical signs: mucous from nostrils, dark green droppings, coughing, poor feeding, death

Question 3

Avian encephalomyelitis

Answer 3

Picornavirus. Transmission is commonly vertical (transovarian) but can be lateral (fecal-oral) as the virus can survive in feces for several weeks. Many older animals remain carriers. Therefore, treating only the symptomatic animals is not an effective strategy. The best prevention strategy is to vaccinate breeder animals to prevent transmission to progeny and to provide them with maternal immunity during the susceptible period.

Question 4

Avian tuberculosis

Answer 4

Rarely seen in commercial chickens. Signs develop late in infection with weight loss, lethargy, and lameness. Granulomatous nodules of varying sizes are commonly found in the liver, spleen, bone marrow, and intestine. Other tissues may also be involved. Caused by Mycobacterium avium var avium. Several strains or serovars can cause disease. Large number of acid-fast bacteria provide a tentative diagnosis.

Question 5

Avibacterium paragallinarum

Answer 5

gram-negative, pleomorphic, microaerophilic rod. Clinical signs include respiratory disease. Clinical signs: nasal discharge, sneezing, and swelling of the face underneath the eyes. Older birds seem to be more susceptible. Diagnosis is based on isolating the organism or inoculation of a healthy bird and then evaluating the development of clinical signs. Swell of the face and wattle must be differentiated from fowl cholera, which is caused by Pasteurella multocida.

Question 6

Avipoxvirus Infection

Answer 6

Causes scabbing skin lesions or diptheric lesions in the respiratory tract, septicemia

Question 7

Bordetella avium

Answer 7

turkey coryza

Question 8

Candidiasis

Answer 8

thrush or sour crop, can occur post treatment with penicillin or nystatin

Question 9

Cheyletiella

Answer 9

mite “walking dandruff”

Question 10

Chlamydophila psittaci

Answer 10

causes lethargy, respiratory, and GI signs

turkey (Ornithosis): nasal discharge, weight loss, inappetence, and death. PM: pneumonia, multifocal necrosis in the liver and spleen, and severe pericarditis. Histopathology: many basophilic intracytoplasmic inclusions in the affected organs.

Treatment: Doxycyline

Question 11

Chondrodysplasia in Turkey

Answer 11

Choline deficiency; can occur in chicks as well as young turkeys, but turkeys have a particularly high choline requirement. Causes stunting, poor feathering, and short thick bowed legs.

Question 12

Cnemidocoptes pilae

Answer 12

“scaly face/leg” can be treated with topical or oral ivermectin. Most common in birds that are immunocompromised, and beak deformity may be permanent oven after the mite is cleared

Question 13

Coccidiosis

Answer 13

fecal-oral transmission

Protozoal gastrointestinal parasite

Clinical signs include mucus-like or bloody diarrhea, dehydration, anemia, listlessness, ruffled feathers, stunted growth, and death. Drop in egg production

Treat flock with Amprolium

Question 14

Cryptococcus

Answer 14

organism with large capsule seen with India Ink

Systemic fungal disease, usually don’t show any clinical signs

Zoonotic - can be fatal in people

Question 15

Dermanyssus gallinae

Answer 15

“red mite” ectopic parasite - treat environment, they are nocturnal feeders and severe infestations can cause anemia and decrease reproductive potential. Management depends on effective treatment of the environment with residual insecticides. Individual animals can be treated with a variety of topical agents but long term management depends on environmental control

Question 16

Egg Drop Syndrome

Answer 16

atadenovirus-induced disease characterized by the production of pale, soft-shelled, and shell-less eggs by apparently healthy laying hens

Question 17

Eimeria in turkey treatment

Answer 17

add amproline to water

Question 18

Erysipelas

Answer 18

gram-positive, slender, pleomorphic rods in the liver

Treatment is rapid-acting penicillin simultaneously with erysipelas bacterin.

turkey’s dying suddenly after exhibiting ataxia and weakness. Diffuse darkening of the skin and enlarged and friable livers and spleens in affected animals. Gram-positive, slender, pleomorphic rods. Treat with Intramuscular sodium penicillin

Question 19

Fowl Cholera

Answer 19

Caused by Pasteurella multocida, a Gram-negative, non-motile, pleomorphic rod. As with most poultry diseases, it is preferable to prevent introduction of the disease into a flock with biosecurity measure. If treatment is attempted, it should ideally be based on culture and sensitivity but sulfonamides, tetracyclines, or penicillin are most often used.

Diagnosis: Gram-negative bacteria in blood or tissue

Question 20

Fowlpox virus

Answer 20

Pox virus - also known as avian pox, sore head, or avian diphtheria.

Intracytoplasmic inclusions

Relatively slow-spreading disease that can spread by contact or by mosquitoes that may harbor infective virus for greater than a month.

Dry firm - main sign is raised, whitish wart-like lesion of unfeathered areas (head, legs, vent, etc.). The lesions heal in about 2 weeks. Unthriftiness, decreased egg productiona dn retarded growth may be seen. Mortality is low with this form of the disease.

Wet form - mainly involves the oral cavity and upper respiratory tract. Lesions are diphtheritic and can ulcerate or erode mucous membranes. Marked respiratory involvement can lead to mortality.

A diagnosis is usually based on flock history and presence of these lesions. This is a pox virus and there is no specific effect treatment but there is a vaccine. Disease control is best accomplished by preventive vaccine as sanitation alone will not prevent spread of disease. Several vaccines are available and a single application results in permanent immunity.

Question 21

Heterakis gallinarum

Answer 21

a nematode parasite that lives in the cecum of some galliform birds, particularly in ground feeders such as domestic chickens and turkeys. It causes infection that is mildly pathogenic. However, it often carries a protozoan parasite Histomonas meleagridis which causes of histomoniasis, blackhead disease

Question 22

Histomonas meleagridis in turkey

Answer 22

Protozoan parasite; also called blackhead or infectious enterohepatic, is fatal to turkeys but less pathogenic to chickens. It causes extensive necrosis of the liver and cecum. For this reason, chickens and turkeys should not be housed together and turkeys should not be housed in areas where chickens were previously housed.

Question 23

Infectious Coryza

Answer 23

bacterial disease that causes acute respiratory infection with nasal discharge, sneezing, and facial swelling; can effectively be treated with antibiotics

caused by Avibacterium paragallinarum in chickens

and Bordetella avium in turkeys

Question 24

Infectious laryngotracheitis

Answer 24

Herpesvirus; acute infection which results in dyspnea, coughing, rales, and bloody tracheal discharge. Mortality is variable but can reach up to 50%.

Diagnosis: intranuclear inclusion bodies in tracheal epithelium or by isolation of the virus through tissue samples.

Treatment: Aimed at prevention and supportive care if cost effective. Vaccination is recommended

Question 25

Knemidocoptes mutans

Answer 25

Mite - also know as scaly leg mite. White-grey debris forms between and on the surface of the scale resulting in the honeycomb crusts. The legs may become thickened and distorted. Diagnosis can usually be made by skin scraping or examination of the underside of a crust microscopically to detect the mite. The microscopic evaluation reveals two mites that look substantially different. These are the male and female Knemidocoptes mites. The adult female is almost round with short legs and devoid of suckers. The adult make is small with longer legs and suckers on long stalks. Treatment of choice is ivermectin.

Question 26

Laminosioptes cysticola

Answer 26

Subcutaneous mite and typically causes 1-3 mm nodular subcutaneous lesions.

Question 27

Liver parameters for avian species

Answer 27

Bile acids and AST most useful

Question 28

Lymphoid leukosis

Answer 28

caused by an avian retroviruse

Chickens with lymphoid leukosis have few typical clinical signs. These may include inappetence, weakness, diarrhea, dehydration, and emaciation. Infected chickens become depressed before death. Palpation often reveals an enlarged bursa and sometimes an enlarged liver. Infected birds may not necessarily develop tumors, but they may lay fewer eggs.

Diffuse or nodular lymphoid tumors are common in the liver, spleen, and bursa -> findings will confirm disease, virus too widespread for isolation

Question 29

Merek’s Disease

Answer 29

herpesvirus, characterized by lethargy and unilateral leg paresis. Enlarges vagus and sciatic nerve seen on PM. Other findings could include diffuse or nodule white tumors int eh liver, spleen, gonads, heart, kidney, lung, or muscle, enlarged feather follicles, and an atrophied bursa. The final diagnosis is usually made by isolating the herpesvirus from lymphocytes obtained from the buffy coat.

Vaccine available, efficacy questionable but has improved

Question 30

Most common cause of liver damage in broiler chickens

Answer 30

Cholangiohepatitis from Clostridium perfringens infection. This is a common cause of ascites in this bird.

Question 31

Mycobacterium avium var avium

Answer 31

causes Avian tuberculosis, granulomatous disease throughout the liver and GI tract.

Question 32

Mycoplasma gallisepticum

Answer 32

causes severe sinusitis and air sacculitis in turkeys with much milder signs in chickens. Diagnosis is made by ELISA, rapid plate agglutination, or PCR. Secondary pathogens commonly play a role in this disease.

Question 33

Newcastle Virus

Answer 33

Paramyxovirus

Causes signs that can range from respiratory, GI, or neurologic signs. Caused by hemagglutinating virus

Onset is rapid, and signs appear throughout the flock within 2–12 days (average 5) after aerosol exposure. Spread is slower if the fecal-oral route is the primary means of transmission, particularly for caged birds. Young birds are the most susceptible. Observed signs depend on whether the infecting virus has a predilection for respiratory, digestive, or nervous systems.

Mortality can be as high as 100%

can be isolated from oropharyngeal or cloacal swabs or tissues from infected birds by inoculation of the allantoic cavity

Vaccine available

Question 34

Ornitharpsus sylviarn

Answer 34

Northern fowl mite and often infect the feathered regions around the vent. They spend the entire life cycle on the host. treat chicken

Question 35

Ornithonysses bursae

Answer 35

Tropical fowl mite and often infect the feathered regions around the vent. They spend the entire life cycle on the host

Question 36

Pacheco’s Disease

Answer 36

herpes virus, incubation period longer than most quarantine periods, inclusion bodies confirms diagnosis

acute viral hepatitis, primarily in parrots

Question 37

Plasmodium relictum

Answer 37

Avian malaria: Intraerythrocytic parasite of birds. The nucleus of erythrocytes is often displaced tot eh periphery of the red blood cell in certain stages of the parasite’s life cycle. It most commonly affects passerines and is transmitted by mosquitoes. The gametocytes often contain a yellow-brown iron pigment. Many birds are asymptomatic, but the disease may cause hemolytic anemia.

Question 38

Proventriculus

Answer 38

Glandular stomach

Question 39

Reticuloendotheliosis

Answer 39

lymphoma in chickens and turkeys caused by an avian retrovirus

Question 40

Ruptured cervical air sac

Answer 40

can rupture and air accumulates under skin

Question 41

Sarcoptes

Answer 41

tunnels into the tissue under the scales of the legs

Question 42

Trombicula alfreddugesi

Answer 42

“harvest mite” Common chigger of birds. They attach to the wing, breast, and necks of poultry. Birds that are heavily infested may become weak, stop eating, and die.

Question 43

Turkey Deep Pectoral Myopathy

Answer 43

heritable

Question 44

Turkey Spontaneous Cardiomyopathy

Answer 44

“round heart disease” - diagnosis from necropsy

Characterized by sudden death, etiology unknown

Question 45

Ventriculus

Answer 45

Grinding stomach