Coccidiosis: The silent killer of poultry flocks

Coccidiosis is a major disease impacting the poultry industry globally.

For many years, it has been associated with indigenous chickens reared on the free-range system and occasionally among wild and game birds.

It is caused by a protozoal organism scientifically christened Eimeria. This organism is known to invade the intestinal lining of poultry following direct ingestion from contaminated litter. Once inside the intestinal gut of a chicken, they destroy the inner lining of the stomach, disrupting the bird’s ability to digest and assimilate nutrients for growth and production.

In severe cases, these invading organisms cause excessive bleeding, malabsorption, diarrhoea and ultimately reduced growth rate.

In my years of poultry medicine, most observant farmers have complained of gradual changes of colour of faecal droppings from the normal dark brown with an occasional white cap to yellow to orange then to red loose faecal droppings.

If nothing is done at this stage, birds tend to lose appetite and weight, and if they are layers, a drop in egg production.

If you do not report these signs to your nearest vet or chick supplier, you are likely to see mortality hit 10 per cent within three weeks.

If noticed in good time and appropriate treatment done, birds tend to recover within 10-14 days. In mild or sub-clinal infection, birds lose performance in terms of poor growth rates and drop in egg production and fertility. The infective stage is the egg (oocysts), which is generally found on litter, soil and manure and is relatively resistant to common disinfectants.

There are about eight known species affecting chickens and are isolated from different parts of the gut of a chicken. The eggs are known to live for up to 15 days in a moist-wet litter and can stay in the soil for three to nine months.

This is the main reason why a concrete floor is recommended in a chicken house as it is easier to clean, disinfect, and kill these nagging parasites.

The infective eggs can be transported by flies, beetles, dust, and rodents from one shed to another, infecting neighbouring flock units.

It is, therefore, important to maintain good spacing if you are keeping two flocks of different ages in one site at a minimum of 100 feet away from each other.

Coccidiosis affects poultry of all ages but is more common in slow-growing birds than in broilers. However, a good diagnosis is recommended by a qualified vet. The control measures include Keeping birds in-house, which goes a long way in reducing the incidence of infection.

The oocysts are known to live for long in the soil, so earthen floors predispose birds to this condition. Good impaction of our earthen floors in poultry units with a mixture of cement and clay soil is one step in reducing the chances of disease proliferation.

Secondly, avoid unnecessary visits to poultry units and completely stop the access of rodents, wild birds and beetles into the flock units using conventional traps and baits.

Select the most appropriate disinfectants containing Glutaraldehyde components for a good and thorough clean-down followed by at least a 21-day rest period before the next placement. Also, ensure your litter in the flock unit is always dry and friable all the time. Repair any water leaks and ensure the units are properly ventilated all the time to remove any excess moisture. Treat diarrhoea immediately it crops up.

Dry litter will reduce the extreme multiplication of the oocysts in the litter.  Stick to the correct stocking density for the type of bird and system.

If the problem persists, consider vaccination of the flocks. This option is however very expensive and only done for elite birds.

Finally, the good news is that there are plenty of anticoccidial products that can be used to treat affected flocks. Consult your veterinarian about the right choice of drugs for your flocks. The treatment can be done in soluble drinking water or through the feeds.

[Dr Messo is the company veterinarian, Kenchic; [email protected]]