Species affected: Chicken, turkey. Age affected: Young (2-20 weeks).
Causes: Reovirus related to tenosynovitis virus as well as other viruses. Spread by vertical or horizontal routes and faecal contamination.
Effects: Incubation period is 7-14 days. Stunting, abnormal feathering, pale combs, wattles, and legs are seen. Higher early mortality, weak legs, CNS signs (tremours, incoordination) and passage of undigested food in faeces can also occur. Delayed and poor egg production peaks may occur in layers and breeders.
There are a number of enteric disease conditions affecting young poultry that go undiagnosed with respect to identifying a definite aetiological agent. Thus a group of diseases of this nature have been termed “viral enteritis” but diseases with similar signs have been reported from many different countries under many different names. These include “malabsorption syndrome” “infectious stunting syndrome” broiler runting syndrome” “pale bird syndrome” and “helicopter disease”. In turkeys, names such as “turkey viral enteritis” “poult enteritis” “malabsorption syndrome” or “maldigestion syndrome”.
Several viruses have either been observed or isolated from the intestinal tract of chickens experiencing viral enteritis. A number of viral particles resembling either caliciviruses, reoviruses, coronaviruses, togaviruses, parvoviruses and picornalike viruses (pseudopicornaviruses) have been identified. One virus isolated from the intestines of four-day-old chickens showing signs of infectious stunting syndrome has been named the FEW virus. However, reoviruses have been most consistently isolated from these diseases.
Incubation period of 7-14 days.
Stunting (stunting or runting syndrome), abnormal feathering (helicopter disease), pale comb, wattles and legs in broilers (pale bird syndrome) are seen.
Higher early mortality, weak legs, CNS signs (tremors, incoordination) and passage of undigested food in faeces can occur.
Delayed and poor egg production peaks may occur in layers and breeders. Can be confused clinically with cystic enteritis in chickens and poultry enteritis (PEMS). With cystic enteritis the intestinal villus have cyst in the Krypts.
Enteritis can cause undigested feed in intestines and pale intestines, haemorrhages around heart may also be seen. Anaemia seen as decreased pigmentation and atrophy of the pancreas and bursa of Fabricius can occur.
Vaccination of pullets with live and killed antigenic reovirus subtypes has been shown to provide parental immunity and the reduction of this syndrome in broilers in many parts of the world.