Adeno Coli infections

Adenovirus infections have been described worldwide in numerous avian species. The pathogenicity of the viruses is usually low and their precise role in clinical disease is often not clear. Most Adenoviruses are regarded as complicating organisms in diseases primarily induced by other agents or, as component of multi factorial problem. A few Adenoviruses, however, can be considered “exceptions” that are highly and primarily pahtogenic, for example: egg drop syndrome (EDS) virus, quail bronchitis virus, haemorrhagic enteritis virus and pigeon Adenoviruses. Pigeon Adenoviruses are responsible for two distinct disease entities, both causing serious harm to the pigeon population.

The most common and well-known type of the disease is caused by Adenovirus type I. We know these problems for over twenty years.
One or two young birds that start to vomit and become ill with less appetite and green droppings. It was never a big problem and only occurred in a few lofts. Incidentally a pigeon could die. We believe that this Adenovirus type I only triggered a serious E-Coli infection. For this reason we speak of Adeno-Coli syndrome. However, in the past 5-10 years the problem has increased and changed in symptoms. Nowadays we see many, many lofts in Western Europe where there are big problems with young birds, especially in April, May, June, July and August. We see a high morbidity (degree of being infected) up to 90% of the young pigeons.
Symptoms: less appetite, vomiting, green slime or yellowish droppings, birds get skinny. They really look ill and may die after a couple of days.
The diagnosis in a laboratory is sometimes difficult to make. The Adenovirus itself is hard to find but E-Coli bacteria are mostly present. But the symptoms are so specific that an experienced pigeon veterinarian or a smart fancier knows what is going on!!
The problem with the E-Coli bacteria is that they are normally present and helpful for the organism. They are normally located in the intestines of healthy pigeons. All of a sudden they can turn into pathogenic Coli.

We may see different cases of the disease in the loft. A pigeon can die from a combination of Adeno and Coli but also from a pathogenic Coli, especially in case of septicaemie, then the pigeons will die very acutely. The classical Adenovirus (type I) infections only occurs in pigeons under the age of one year.
To make things more complicated we have since the summer 1991 a very aggressive variant of the classical Adenovirus. We call it Adenovirus type II.
I was the first to describe this dramatic disease, not knowing than that it was a different type of the classical Adenovirus.
I was confronted with many lofts in South West of Holland with following very typical symptoms normal healthy looking pigeons mostly old birds would all of a sudden eat less. Only drink a little water. Start trying to vomit and produce yellow, not slime, only yellow plaques without dropping structure. The birds die mostly the next day heavily breathing as if they have a bad long disease.

However, they die of septicaemie due to a massive liver infection and destruction of the liver. I saw thousands of such cases and sent in pigeons to the best clinic in the world for laboratory research in pigeons: the university of Gent in Belgium. They found out, after 1 ½ year, that this was a variant of the classical Adenovirus and called it type II.

In the meantime type II is still present but never again as massive and destructive as I saw it in 1991. Nowadays it complicates also the different forms of Adenocoli. When we see the symptoms as described, we have the following possibilities:
A Adenovirus type I
B Adenovirus type I plus E-Coli bacteria
C Pahtogenic E-Coli bacteria
D Adenovirus type II.

We also see complications with other bacteria such as streptococcen, staphylococcen and others. In cases A, B and C we will have tremendous good results with specific antibiotic combinations. In case D we will have no success at all with any therapy.
At the Gent university they are trying to make a vaccine out this specific virus of pigeons, but it will take a couple of years to have a vaccine ready.
It is a pity that probiotica and acids to lower the PH of the drinking water, do not prevent the incidence of the disease. Birds that have overcome the disease may be good flyers in the future. We have a lot of such examples!

Important is a quick diagnose and as soon as possible an effective treatment.

Dr. H.J.M. de Weerd

------------------------------------------------------------------------------------------------------------------------------------------------------------------------