Economics:Coccidiosis in cattle is one of the five most economically important diseases of the cattle industry. It is estimated to cost the industry $100 million or more annually.
The disease:Coccidiosis in cattle usually presents as acute diarrhea with or without blood (Fig. 1), straining, severe weight loss, and not uncommonly as a neurologic form that usually results in death of the animal. The more chronic form of the disease causes growth retardation, and/or acts as a stressor causing increased susceptibility to other infections, such as salmonellosis (intestinal disease), or Bovine Respiratory Disease. Coccidiosis is primarily a disease of young animals but can affect older animals that are in poor condition.
It occurs commonly in overcrowded conditions, but can occur in free-ranging conditions that have congregating areas, such as feed grounds and watering areas.
The disease agent: Coccidia are protozoan parasites that are host specific; e.g., cattle have their specific coccidian (Eimeria sp., Fig. 2), poultry have their coccidia, etc. The oocyst (infective form of the parasite) is usually shed in the feces of affected animals and that of inapparent carrier animals. The oocyst is highly resistant and can survive in moist shaded areas for several years.
Transmission:Coccidiosis is transmitted from animal to animal by the fecal–oral route. Infected fecal material contaminating feed, water, or soil serves as carrier of the oocyst; therefore, the susceptible animal contracts the disease by eating and drinking, or by licking itself. The severity of clinical disease depends on the number of oocysts ingested. The more oocysts ingested, the more severe the disease.
Diagnosis:Coccidiosis is diagnosed by clinical signs, fecal examination by flotation or smear, and by postmortem examination.
Treatment:Isolate the sick animal to prevent increased contamination of the premises. Clinical signs usually occur about seventeen days after ingestion of oocysts. By the time clinical signs occur, the dam age is far advanced, and the life cycle in the animal is completed. Amprolium at 10 mg/kg/day for five days and sulfonamides are commonly used as treatments for clinical disease. Supportive treatments and drugs to prevent secondary infections are commonly recommended due to the animal’s debilitated state. Remember, if there is one clinical case in a group of cattle, it is highly probable that others have been exposed and harbor coccidia in the intermediate stages of development. Due to the drug susceptibility of the parasite in the intermediate stages of development, preventive
measures should be instituted.
Control:Anticoccidial drugs commonly used in cattle should be used at label recommendations, paying careful attention to maintaining preventive levels for periods long enough (28 days or longer) to affect the life cycle of coccidian.
Source:Glenn Selk & John G. Kirkpatrick, DVM, Oklahoma State University