Ascariasis is a parasitic disease caused by a type of roundworm known as Ascaridia galli, which infests the gastrointestinal tract of chickens. This disease is particularly prevalent in young birds up to three months of age and can significantly impact the production and health of infected flocks.
While Ascariasis is primarily a concern for the poultry industry, it is also important from a public health perspective, as humans can potentially contract the disease through consuming contaminated poultry products. As such, efforts to control and prevent Ascariasis in poultry are important in ensuring animal and human health.
Ascariasis Management in Chicken
Causes of Ascariasis Disease
An infestation of the Ascaridia galli roundworm in the intestines of chickens causes Ascariasis. The following factors increase the risk of infection:
- Dietary deficiencies: Chickens deficient in key nutrients such as vitamins A, B, and B12, as well as various minerals and proteins, may be more susceptible to Ascariasis.
- Reusing litter: If litter from a previous flock is reused, it can contain infectious eggs from previous infestations, increasing the risk of infection in subsequent flocks, especially in the case of broilers.
- Poor sanitation: Dirty and poorly maintained poultry houses can harbor infectious eggs and increase the risk of infection.
- Contaminated feed or water: Feed and water contaminated with infectious eggs can also contribute to the spread of Ascariasis.
- Age of chickens: Young birds up to 3 months of age are more susceptible to infection, while chickens over three months are more resistant.
- Environmental factors: Optimum temperature and moisture conditions can lead to the hatching of A. galli eggs, which become infective to chickens in 10-12 days. Additionally, A. galli eggs are quite resistant to low temperatures, allowing them to survive in the environment for extended periods.
Disease Cycle of Ascariasis
The disease cycle of Ascariasis begins when infected chickens pass Ascaridia galli eggs in their feces. These eggs become embryonated and develop into an infective stage (L3) within 10-20 days, depending on environmental factors such as temperature and humidity. The eggs can survive for years in deep litter systems depending on the conditions.
The lifecycle is complete when a new host (another chicken) ingests the infective eggs from contaminated water or feed. The larvae hatch within 24 hours in the duodenum/jejunum, enter the histotropic phase and embed themselves into the mucosal layer of the intestine. The more eggs present, the longer the histotropic phase may last, which can be between 3 to 54 days.
The adult A. galli worms may migrate through the large intestine and cloaca lumina and end up in the oviduct, where they can be incorporated into the hen’s egg. Occasionally, earthworms can ingest A. galli eggs, and the parasites are transmitted when the chicken ingests the worm. This cycle repeats, leading to continued infection and disease transmission in chicken populations.
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Symptoms of Ascariasis Disease
- Poor bodily condition and weight loss: Chickens with Ascariasis may exhibit a generally poor bodily condition and experience weight loss despite consuming sufficient feed.
- Anaemia: The roundworms can cause damage to the intestinal lining, leading to blood loss and anaemia in affected birds.
- Diarrhea: Ascariasis can cause gastrointestinal inflammation and irritation, leading to diarrhea in affected chickens.
- Haemorrhagic enteritis: In heavy infestations, Ascariasis can cause severe gastrointestinal inflammation and lead to haemorrhagic enteritis, a condition characterized by blood in the feces.
- Increased mort