Infectious stunting syndrome ISS By Prof Dr Mohamed

Infectious stunting syndrome (ISS) By Prof. Dr. Mohamed H. H. Awaad Faculty of Veterinary Medicine, Cairo University

Malabsorption syndrome Helicopter disease Synonyms Umbrella-bird Brittle bone disease Stunting-runting syndrome Chicken anemia Pale bird syndrome. In turkeys: Turkey viral enteritis, Poult enteritis, Malabsorption syndrome Maldigesion syndrome.

Definition Infectious disease that affects the intestinal tract of young broilers and specially breeders. Characterized by severe growth depression.

Etiology Primary cause(s) has not definitely established Enteropathogens causing viral enteric infections Other viruses Reoviruses Parvoviruses Coronaviruslike particles FEW virus Caliciviruses Adenoviruses Orthoreoviruses (in turkeys) Togaviruslike agent Reticuloendotheliosis virus, several other bacteria and non-infectious agents (e. g. Mycotoxins) have been claimed to be involved.

Economic losses Diminished weight gains Feed conversion Marketability Carcass condemnation

Pathogenesis and epizootiology The enteric tract has many functions: 1 - Providing a means by which the body derives nutrition. 2 - Furnishes protective mechanisms to safeguard the hos 3 - Serves as an environment for other living organisms. So Combination of, and interactions among viruses, bacteria, parasites and noninfectious agents may be necessary to elicit or increase severity of viral enteric disease.

Pathogenesis and epizootiology Enterolike viruses infect villous epithelial cells Pancreatic lesions Togaviruslike agent isolated from pancreatic ducts Dysfunction of intestine. Maldigesion Obstruction. Vertical and horizontal transmission of these viruses are proven.

Viruses Infect villous epithelial cells in the mid-small intestine Dysfunction of the intestine leads to impaired digestion and absorption of lipids and fat-soluble vitamins A, D and E and carotenoids. Runts Decreased Wt. gains (Very small birds about 120 -150 g) Stunts (Uneven growth)

Symptoms

Encephalomalacia Yellow-head Encrustation of mouth commissars Granulation in eye-lids Feathers 0 range diarrhea Enlarged abdomen Witch-like appearance of the beak Skeletal abnormalities (lameness -brittle bones) Poor pigmentation (Pale-bird syndrome) Feed conversion - Mortality

Stunts-Runts

Post mortem Lesions

Enlarged proventriculus

Distended abdomen

Shrunken, thin, white and firm pancreas

Intestine containing undigested orange feed Catarrhal enteritis with white color and Dilated intestine.

Thickening of the growth plates of lo bones. Other gross lesions Arthritis and osteoporosis. Bursa of Fabricius and thymus gland a atrophied. Femoral head disintegration on disarticulation of the coxofemoral join

Histopathological lesions

Later stages: Extensive atrophy of exocrine tissue and fibrous replacement of pancreatic acini Early stages: Degeneration, atrophy, and fibrosis of exocrine tissue of pancreas. Marked vacuolation of acinar cells. Pancreas

Catarrhal enteritis, atrophic intestinal villi, inflammation and degeneration of crypts of Liberkuhen glands with lymphocyte infiltration. Intestine

Other histopathological lesions Proventriculitis with focal necrosis and infiltration of interglandular tissue with mononuclear cells. Bones abnormality in the femur growth plate with necrosis of cartilage. Thymus cortex is thinner and difficult to be differentiated from medulla. Atrophy of follicles of Bursa of Fabricius.

Diagnosis igns and lesions are quite sufficien for routine diagnosis.

Prevention and Control 1 - Thorough cleaning and disinfecting of the affected premises after each crop ( Basic Veterinary hygienic measures). 2 -In affected flocks dietetic measures, such as the use of good quality fat and / or replacement of fat energy by carbohydrates are of some help.

Prevention and Control. . Cont. 3 -Research into a broiler that resist ISS breeds is on its way. 4 - Vaccines (at 1 day of age with viable attenuated Reovirus by S/C) route or vaccination of breeders (with viable or inactivated vaccines) provides maternal immunity as well as limits transovarian transmission.

Thank you