FOLLOWING the avian flu which affected different areas, there is another disease which might affect the poultry industry.
It is called the blackhead disease (histomoniasis), which is a crucial poultry disease that affects turkeys, chickens, game birds, and even quails.
According to the United States Food and Drug Administration (FDA), the disease is caused by Histomonas meleagridis, a protozoan which is transmitted to the bird by the parasite Heterakis gallinarum, a type of nematode, or roundworm.
FDA says that the lifecycle of H. meleagridis is complex. The protozoa multiply in an infected bird’s cecum (a part of its digestive tract). The protozoa move to the bird’s intestines where the roundworm H. gallinarum lives.
The roundworm eats the protozoa, causing the roundworm’s eggs to become infected with H. meleagridis. The protozoal-infected eggs are then shed in the bird’s droppings.
Healthy birds become infected with H. meleagridis when they eat food, invertebrates (such as earthworms), or bird droppings that are contaminated with the protozoa.
Direct bird-to-bird transmission can also occur within a flock.
This is because chickens, partridges, and pheasants commonly have the roundworm H. gallinarum in their intestines, they are often the source of the protozoal infection for other birds.
Birds with blackhead disease are usually listless and have drooping wings, unkempt feathers, and yellow droppings.
Typically, the cecum and liver of an infected bird will become inflamed and develop ulcers.
The FDA says that young birds become sick quickly and usually die within a few days after clinical signs appear.
Adding that the disease develops more slowly in older birds and they often become emaciated and may eventually die.
On the other hand, turkeys are highly susceptible to blackhead disease. Once a turkey flock has been infected, mortality can reach 70 to 100 percent.
A survey of professionals representing the United States (US) turkey industry reported at least 50 outbreaks of the disease each year since 2009.
As the severity of the disease in turkeys is associated with factors such as bird age, virulence of the strain, breed or strain of the animal, less severe cases of histomoniasis may not be reported and the economic loss from the disease is not accurately captured.
However, blackhead disease is less severe in chickens but can lead to poor health and reduced egg production.
Meanwhile, the Histostat (nitarsone), an arsenic-based animal drug, was the only FDA-approved drug to prevent blackhead disease in poultry.
But in 2015, the drug company voluntarily stopped marketing Histostat and requested withdrawal of the drug’s approval due to concerns about inorganic arsenic levels in treated birds.
Currently, there are no animal drugs approved to prevent, treat, or control blackhead disease in the US, the FDA says.
It added that the disease is caused by numerous sub-strains of Histomonas meleagridis, which are often localized to a specific farm or area.
H. meleagridis is sensitive to oxygen and temperatures lower than the body temperature of birds, rendering the bacteria non-infectious after a few hours spent outside of a host, FDA says. (jaypeeyap@ymail.com/PN)
