|
Coccidiosis is a disease of fowl caused by a microscopic animal or protozoa and is characterized by diarrhea, unthriftiness and variable levels of mortality. In spite of much research to advance the control and treatment of this disease, it remains the most costly disease of the poultry industry. Coccidiosis is caused by microscopic animals called coccidia. There are many species of coccidia that can infect fowl, domestic animals and humans. Each species of coccidia is host specific and does not infect a wide variety of animals. After an outbreak of a specific species of coccidia, the flock will develop a resistance to the exposed coccidia species but remain resistant to other infective species. This means that a flock may experience several outbreaks of coccidiosis, each being caused by a different species of coccidia. Chickens are susceptible to any of nine coccidia species, turkeys are susceptible to seven species and quail are susceptible to at least four different species of coccidia. Coccidiosis is transmitted by direct or indirect contact with droppings of infected birds. When a bird ingests coccidia, the organisms invade the lining of the intestine and produce tissue damage as the undergo reproduction. Within a week after infection, the coccidia shed immature descendants that are referred to as oocysts. The oocysts shed in the droppings are not capable of infecting another bird unless they pass through a maturation process (sporulation) in the litter. This sporulation occurs within a one to three day period if the litter is warm and damp but can take much longer if the conditions are cool and dry. After sporulation the coccidia are infective if consumed by a new host bird. The number of infective coccidia consumed by the host is a primary factor as to the severity of the resulting infection. An infection may be mild enough to go unnoticed while a large infective dose of coccidia may produce severe lesions that can cause death. Coccidia survive for long periods outside the bird's body. They are easily transmitted from one house to another on contaminated boots, clothing, free-flying birds, equipment, feed sacks, insects and rodents. Coccidiosis usually occurs in growing birds and young adults. It is seldom seen in birds under three weeks or in mature birds. Signs of an outbreak include birds that are pale, droopy, tend to huddle, consume less feed and water, have diarrhea, and may become emaciated and dehydrated. Laying hens will experience a reduction in rate of egg production. Cecal coccidiosis may produce bloody droppings and anemia that is often followed by death. Intestinal coccidiosis is not as acute and is more chronic in nature. It produces less mortality than the cecal form. Lesions of the infection depend on the species of coccidia causing the problem, its severity and stage of the disease. Cecal coccidiosis may produce a ballooning of the cecal pouches that is filled with free blood. A later stage is characterized by cecae that are filled with a material with a cheesy consistency and being tinged with variable amounts of blood. Lesions of intestinal coccidiosis vary from a rather mild enteritis to a severe necrotic or hemorrhagic type. Cecal coccidiosis may be confused with blackhead and salmonellosis due to their similar lesions. Intestinal coccidiosis may be confused with hemorrhagic anemia syndrome and other enteric diseases. Definite diagnosis is made from the microscopic examination of scrapings of the digestive tract and identification of the coccidia organisms. Since it is common for healthy birds to possess some coccidia, consideration of flock history and lesions must be considered before making diagnosis and treatment recommendations. It is difficult, if not impossible, to prevent coccidiosis by sanitation alone. It is best prevented by addition of a drug (coccidiostat) to the feed that controls the growth of coccidia in the digestive tract. Many coccidiostats are available commercially. Coccidiostats should not be indiscriminately used and recommendations must be followed precisely. A coccidiosis vaccine is also available commercially. The product is useful only in certain types of poultry operations and must be used as recommended. Seek expert advice before using the vaccine.
by: The items listed below provide links to MCES resources available on the world-wide-web. Specific information on poultry related topics that is not available through these sites can be requested from Mississippi State University; Poultry Science Department; Box 9665; Mississippi State, MS 39762 or by e-mail at
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
';
document.write( '' );
document.write( addy_text48310 );
document.write( '<\/a>' );
//-->\n This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
. |
