ByProf. Dr. Mohamed H. H. Awaad

Faculty of Veterinary Medicine, Cairo University

Infectious stuntingInfectious stuntingsyndromesyndrome

(ISS)(ISS)

Malabsorption syndrome Helicopter disease Umbrella-bird Brittle bone disease Stunting-runting syndrome Chicken anemia Pale bird syndrome.

In turkeys:Turkey viral enteritis, Poult enteritis, Malabsorption syndrome Maldigesion syndrome.

SynonymsSynonyms

DefinitionDefinitionInfectious disease

that affects the intestinal tract of

young broilers and specially breeders. Characterized by

severe growth depression.

EtiologyEtiology

Primary cause(s) has not definitely establishedPrimary cause(s) has not definitely established

Enteropathogens causing viral enteric infectionsEnteropathogens causing viral enteric infections

ReovirusesOther viruses

Orthoreoviruses (in turkeys)Orthoreoviruses (in turkeys)

Togaviruslike agentTogaviruslike agent

FEW virusFEW virus

Coronaviruslike particlesCoronaviruslike particles

CalicivirusesCaliciviruses

AdenovirusesAdenoviruses

ParvovirusesParvoviruses

Reticuloendotheliosis virus, several other bacteria and non-infectious

agents (e.g. Mycotoxins) have been claimed to be involved.

Economic lossesEconomic losses

Carcass condemnationCarcass condemnationMarketabilityMarketability

Feed conversionFeed conversionDiminished weight gainsDiminished weight gains

Pathogenesis and epizootiology

The enteric tract has many functions:The enteric tract has many functions:

3- Serves as an environment for other living organisms.2- Furnishes protective mechanisms to safeguard the host.

1- Providing a means by which the body derives nutrition.

So Combination of, and interactions among viruses, bacteria, parasites and

non-infectious agents may be necessary to elicit or increase severity

of viral enteric disease.

Pathogenesis and Pathogenesis and epizootiologyepizootiology

Enterolike viruses infectEnterolike viruses infect villous epithelial cellsvillous epithelial cells

Obstruction.Obstruction.Togaviruslike agent isolatedTogaviruslike agent isolated from pancreatic ductsfrom pancreatic ducts

MaldigesionMaldigesionPancreatic lesionsPancreatic lesions

Dysfunction Dysfunction of intestineof intestine..

Vertical and horizontal transmission Vertical and horizontal transmission of these viruses are proven.of these viruses are proven.

Viruses Infect villous epithelial cells in the mid-

small intestine

Decreased Wt. gains

Dysfunction of the intestine leads to impaired digestion and absorption of lipids and fat-soluble vitamins A, D and E

and carotenoids.

Stunts (Uneven growth)

Runts(Very small birds about 120-150 g)

Symptoms

Yellow-head

Witch-like appearance of

the beak

Poor pigmentation (Pale-bird syndrome)

Granulation in eye-lids

Feathers

Skeletal abnormalities (lameness -

brittle bones)

Encrustation of mouth commissars Encephalomalacia

0range diarrhea

Feed conversion - Mortality

Enlarged abdomen

Stunts-RuntsStunts-Runts

Post mortem Lesions

Enlarged proventriculusEnlarged proventriculus

Distended abdomenDistended abdomen

Shrunken, thin, white and firm Shrunken, thin, white and firm pancreaspancreas

Intestine containing undigested orange

feed

Catarrhal enteritis with white color and Dilated

intestine.

Bursa of Fabricius and thymus gland are atrophied.

Femoral head disintegration on disarticulation of the coxofemoral joint

Thickening of the growth plates of long bones.

Arthritis and osteoporosis.

Other gross lesions

Histopathological lesions

Early stages:Degeneration, atrophy, and fibrosis of exocrine

tissue of pancreas. Marked vacuolation of acinar cells.

Later stages:Extensive atrophy of exocrine tissue and fibrous replacement of pancreatic acini

PancreasPancreas

Catarrhal enteritis, atrophic intestinal villi, inflammation and degeneration of crypts of Liberkuhen glands with

lymphocyte infiltration.

IntestineIntestine

Thymus cortex is thinner and difficult to be differentiated from medulla.

Atrophy of follicles of Bursa of Fabricius.

Bones abnormality in the femur growth plate with necrosis of cartilage.

Proventriculitis with focal necrosis and infiltration of interglandular tissue with mononuclear cells.

Other histopathological Other histopathological lesionslesions

Diagnosis

Signs and lesions are quite sufficient 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.

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.

3-Research into a broiler that resist ISS breeds is on its way.

Thank you