Adenovirus


Named after having been isolated from the adenoid tonsils of healthy and sick children, the adenovirus occurs in at least 3 dozen antigenic types. Put together many young pigeons of different origin such as occurs in a one loft derby or in a racing pigeon combine and the stage is set for an infection with adenovirus. One point of view is that it itself does not seem to cause disease in pigeons except that it allows other, normal bacterial inhabitants of the intestinal tract to invade the bird's body and cause disease. The answer must lie in the immune system which is rather immature in the young pigeon. Antibodies against various microbes with which the breeding pigeon was confronted are deposited in the egg and used by the developing youngster.abstract Antibodies also pass via the crop milk to the young pigeon after it has hatched, similar to the way colostrum contains antibodies which are transferred to young mammals. abstract Considering the above, it is not necessary to postulate that an adenovirus is part of the problem associated with young bird disease. This adenovirus may indeed be an innocent bystander.
Each youngster arriving at a one loft derby represents a bag filled with the various microbes present in the loft of its origin. We now mix all those hundreds of bags and their contents resulting in a super micro-flora. Although each yopungster is immune to the micro-flora of its loft of origin, it is now suddenly confronted with micro-organisms from all those other lofts. It may be overwhelmed by these microbes, especially if its own immune status was compromised through "carrying a small bag". It may be that not adenovirus but lack of immunity to the various microbes from different lofts is the cause of young bird disease.

An excellent article was written by Dr David Marx regarding the difficulties, symptoms and progression of this disease complex at Stagnant Fluid in the Crop.
Dr Marx also contributes with an article "The Miracle of Chlorine", the use of which would be expected to at least reduce the transmission of pathogens.
Here now is Dr. L. Dwight Schwartz as he examines the symptoms as well as the transmission of adenovirus to birds as it relates to peafowl:

DISEASES OF PEAFOWL

By Dr. L. Dwight Schwartz, DVM
Avicon, Inc.
Hemorrhagic Enteritis (HE) is an acute and often fatal disorder caused by an adenovirus. The disease is characterized by extensive inflammation and hemorrhage of the intestines. The birds are most susceptible between 4 and 13 weeks of age. The disease is not spread bird to bird but from the ingestion of infected material such as fecal droppings in the feed, water, or litter. Prevention by sound management and vaccination is the best policy since there is no specific treatment. However, antibiotics in the feed or water are a good therapy to prevent a secondary infection which would shorten the recovery period.
Dr. L. Dwight Schwartz points out the route of infection in the peafowl which is also a possible route of infection for pigeons.
Below follows another article written by Dr David Marx about adenovirus problems:
E.COLI IN YOUNG BIRDS
Each young bird season we see an increase in disease involving the bacteria E.coli. E.coli is a normal inhabitant of the digestive system of pigeons. It has disease potential, but usually needs a predisposing condition to allow it the opportunity to cause infection. Several things can "open the door" for E.coli to cause disease. Stress, viral infections, intestinal parasites, and other irritants of the bowel such as chemicals consumed while fielding.

The usual predisposing factor for young birds is adenovirus. It begins appearing when birds are mixed, either in training, races or when accumulating birds from various sources. The adenovirus by itself will not cause disease, but in the presence of E.coli, it allows the E.coli to cause disease. Treating the E.coli infection usually eliminates symptoms although it does nothing for the adenovirus infection; this is usually conquered by the birds own immune system with time. There is not an effective vaccine for adenovirus, so we must just let it run it's course as we try to control the E.coli during outbreaks.

Usually during outbreaks of colibacillosis (E.coli infection), we use a broad spectrum antibiotic such as Amoxicillin to control it. Antibiotics will not prevent it so use them only during an outbreak. The symptoms usually include vomiting in some of the birds, abnormal droppings or diarrhea, and lethargy. The birds will not train or race well during an uncontrolled outbreak.

A fecal culture and sensitivity study will allow one to choose the correct antibiotic to use. Often we just go with one that has a good "track record," and that has little or no effect on the birds, allowing one to continue training, etc. Amoxicillin is my first choice of antibiotics when "shooting from the hip". It is gentle on the pigeon and is the least expensive of the good antibiotics. Use 3 Grams per gallon for about 7 days. Retreatment is often necessary, as things may deteriorate within the weeks after treating, as the viral infection spreads through the flock.

Do not forget not to use antibiotics as a preventive. They will not work as preventive, but will only allow the bacteria to become resistant to it, then it won't work when we really need it.

David Marx DVM
Update (March 4, 2004)
From the German periodical "Die Brieftaube" (2004, Nr. 7):
    Interim Results about examinations regarding various viruses:
    The presence of various viruses in pigeons suffering from Young Bird Sickness was determined at the Universities of Leipzig and Gießen.
  • Adenovirus and Polyomavirus PCR (polymerase chain reaction) tests of the livers were negative as were subsequent attempts at culturing.
  • PCR tests regarding Herpesvirus was positive in 15% which could also be confirmed through cultures.
  • The presence of Circovirus could be confirmed in 90% with the PCR test and 100% of all blood tests were positive as were all tests of the oil gland.
Translated from the German periodical "Die Brieftaube" (2004, Nr. 8):
    The trigger of young bird sickness is the Circovirus in connection with other disease-causing agents. At the FCI-level a related study is running that concentrates itself on how Circovirus is spread. From this comes the question of how one can most effectively fight the virus.
This page was last up-dated on March 4, 2004

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