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Cause and Symptoms — Only birds whose immune systems are suppressed are vulnerable to this disease. There are two types of Adeno Virus that infect pigeons. Type 1 affects young pigeons primarily and causes vomiting and diarrhea, from which many birds recover, Type 2 is contracted by older pigeons and strikes the liver, with most affected birds dying within 24 hours. Some birds display a fluid yellow diarrhea and vomiting before death. But the main sign is sudden death, occurring within 24 hours of the onset. None of the affected birds live longer than 48 hours. E. coli often accompanies Type 1 (which is associated with young pigeons) and complicates the infection, making the diarrhea and vomiting more severe and adding respiratory symptoms. This Type 1 Adeno Virus/E. coil combination is sometimes successfully treated with antibiotics. Cases that are the best managed are those in which the loft environment is good and in which all secondary diseases like canker and coccidiosis are treated so that birds are best able to fight the virus.
Prevention — Adeno virus is always present in a young bird, and it erupts when the immune system weakens or fails. It is important to wait until the 12th week for any type of vaccination. There is currently no vaccine that is proven to be effective against Adeno Virus. It's also important to keep stress in the loft at a minimum and to boost pigeons' general health with vitamin supplements, etc.