Does chicken get typhoid and cholera like humans? That maybe the question running in your mind as you read the heading to this piece. Well, the answer is yes and no.
Yes, for typhoid and no for cholera. This article looks at these two diseases together because they are quite similar. Nevertheless, they have distinct presentations and epidemiology.
Just like typhoid in humans, these two diseases are caused by species of the bacteria Salmonella. Fowl typhoid is cause by Salmonella gallinurum while Fowl Cholera (also called Pullorum Disease) is cause by Salmonella pullorum.
These bacteria cause diseases only in poultry especially turkeys and chicken. There are other Salmonella bacteria that can infect poultry and other animals including human.
Salmonella is therefore a zoonotic concern because it can spread between animals and humans. Both diseases are majorly transmitted via the egg.
This means that infected chicken produces infected eggs that produce infected chicks. However, direct, and indirect contact with infected surfaces can also occur.
What is the difference between the two diseases?
As stated above, they are caused by different species of the Genus Salmonella. In terms of occurrence, fowl typhoid is more common than fowl cholera.
Fowl cholera mostly affects young birds and causes death in chicks up to the three weeks. Fowl typhoid is generally a disease of order birds (growers and adult birds). This is a major difference that aids in diagnosis.
For Fowl Cholera cause the young chicks present with unabsorbed yolk sac on the underbelly. The birds appear weak; they do not eat and will huddle together near a source of heat.
A whitish faecal material is found soiling their vents. Internal lesions will be found in the liver, spleen, lungs, heart, and the gizzard. When it occurs in older birds, the signs are like those of fowl typhoid.
Fowl typhoid causes high mortality in older birds. The birds go off feed, diarrhoea, poor growth, decreased egg production and reduced fertility.
Treatment and control
As the adage goes, control is better than cure. The two diseases are controlled by ensuring that flocks are screened for the diseases and those that are found positive are eliminated.
In fact, through this initiative, developed countries like the USA have been able to eliminate the diseases completely. In many developing countries including Kenya, the diseases are still present.
Pullorum disease is controlled by routinely checking the parent stock of hatcheries to ensure that they are free from the disease.
In Kenya this is a matter of law and is enforce by the Directorate of Veterinary Services. It is paramount that farmers purchase chicks from accredited and certified hatcheries. On the other hand, fowl typhoid is controlled through vaccination.
Dr Nderitu Nyaga S, BVM,MSc
Faculty of Veterinary Medicine and Surgery, Egerton University