Streptococcosis: symptoms, diagnosis and treatment

The sickness streptococcosis is a frequent disorder by pigeons. It is caused by a bacteria Streptococcus gallolyticus and in addition to paratyfus and chlamydiosis it is one of the most common bacterial pigeon diseases.

Dr Ruben Lanckriet

What is streptococcosis

Paratyfus is caused by a Salmonella-bacteria and chlamydiosis or ornitosis by a chlamydophila bacteria. These types of sicknesses shouldn’t be confused with viral diseases (caused by viruses) such as circovirosis, adenovirosis, herpesvirosis. Bacterial diseases can be treated with antibiotics, viral diseases can’t. You can only work preventively with viral diseases by means of vaccination or treating secondary bacterial infections, so as the ‘adeno-coli’ syndrome for example.

Streptococcus is usually confused by pigeon fanciers with paratyfus, which often results in the wrong treatment. The bacteria Streptococcus gallolyticus can be present in the intestines of normal pigeons without causing sickness. It is only when the bacteria travels through the intestine-blood barrier, in other words enters the bloodstream, that serious symptoms can arise. Typical is the sudden death of a pigeon which seemed completely healthy a few hours previously. This has to do with the fact that the bacteria, once in the blood, can very quickly cause serious inflammation in organs and muscles. By experimental infection of healthy pigeons whereby the bacteria was injected directly into the blood, all the pigeons died within a few hours of being injected. Antimicrobial treatment after being infected couldn’t prevent the swift death either .


By milder infections the most common symptoms are difficulty in flying (through inflammation of the muscles and tendons), malaise, slimy droppings, and lack of appetite. Sometimes the only symptom is the death of one or a few pigeons whereby the other pigeons seem completely healthy.

It is not yet known which factors cause the bacteria to enter the blood. On the one side there is the high pressure of infection out the surroundings and factors so as stress, enteritis, etc… Stress seems to be a very important factor with this disease. Yet streptococcosis also shows an epidemiologic pattern, in other words, multiple pigeons from the same colony show symptoms. This indicates that the infection rate and most likely the pathogenic properties of specific bacterial strains (the streptococ sort) are also very important. That’s why it is advisable to treat all the pigeons, even if only a few are showing signs of illness .


The exact diagnosis can only be made by holding an autopsy. There is a great chance that valuable information can be gained from the autopsy of a sick or dead pigeon. This is definitely the case with this disease, but it is also useful for learning about any problems in a pigeon colony. A probable diagnosis can be made on the basis of the symptoms The symptoms will usually have disappeared two days after starting the treatment. Yet it is still advisable to respect the full duration of the treatment .


The treatment consists of amoxicillin or  ampicillin, given for 10 days either individually or in the drinking water. The treatment works very well and the problems by the pigeons infected can soon disappear.

Although it has not been scientifically proved, I know from experience that colonies with a paratyfus problem (whether solved or oppressed)  are often more easily affected by streptococcosis. One of the explanations for this could be that the damage caused to the intestine by salmonella, ensures that streptococcus can easily get into the bloodstream .

When does the disease occur ?

The disease often occurs during the racing season and can be the cause of poorer performances. A typical symptom is the story of arriving home from a race abnormally by a nevertheless smooth race. Top pigeons suddenly miss their prize by hours or come home days later even though the race was very smooth. The prize percentage is lower than normal. Sometimes there is the sudden death of a pigeon at the same time as these competition results and/or a pigeon can no longer fly well. A good pigeon often doesn’t return home from a race which had otherwise gone smoothly. This is due to the pain caused by the inflammation in the muscles and tendons. Sometimes a heavy inflammation can cause whole chunks of the muscle to be lost and replaced by connecting tissue (muscle necrosis).

It goes without saying that such pigeons,  depending on how bad the necrosis is, are no longer suitable for successfully finishing a race. If you treat the pigeons fast enough then this muscle necrosis can be avoided, and it is usually possible to achieve good results with these same pigeons .