KINGDOM PROTISTA
TAXONOMY is the science of defining and naming groups of biological organisms on the basis of shared characteristics. The principal ranks are kingdom, phylum, class, order, family, genus and species. The Protozoa are considered to be a subkingdom of the Kingdom Protista, although in the classical system they were placed in the kingdom Animalia. Members are classified according to their method of movement, if any, which include either tails called flagella, foot-like structures called pseudopodia or hair-like structures called cilia. CRYPTOSPORIDIOSIS
Causitive organism: Cryptosporidiosis is the name given to the disease caused by group of organisms called Cryptosporidium. They are highly infective parasites which cause scour in young calves from one to four weeks old.
Transmission: The organism is spread via the oral-faecal route, with infected animals ingesting the oocytes or eggs present in animal faeces. The organism can also infect humans and those particularly susceptible include the elderly, immunocompromised individuals and young children.
Symptoms: Mild to severe scour, depending on the severity of the infection. The only definitive diagnosis of the scour being caused by this organism is by sending faecal samples from untreated scouring animals for diagnostic testing.
Treatment: No vaccine is available, but treatment can be effective if administered in the early stages. All scouring calves should be isolated and given replacement fluids. Upon diagnosis with cryptosporidiosis, administration of a prescription medicine known as halofuginone lactate should serve to reduce symptoms.
Prevention: Preventative measures include isolation of newborn calves, adequate colostrum consumption after birth, replacement of bedding every couple of days and strict hygiene including proper power washing and disinfection of sheds and creep areas. COCCIDIOSIS
Commonly referred to as ‘blood scour’, the protozoan parasites Eimeria zuernii and Eimeria bovis are responsible for this scour which mainly affects calves from three weeks of age. Coccidiosis is spread in a similar way to Cryptosporidiosis through infected faeces. In the case of coccidiosis, blood is often present in the stools. The disease can only be confirmed by diagnostic testing. Effective treatment for cattle include the oral drenches Vecoxan and Baycox Bovis. Preventative measures against the disease are similar to those
described for Cryptosporidiosis. NEOSPOROSIS
Causitive Organism: A protozoan parasite by the name of Neospora caninum causes this condition, which as the name suggests, is carried by the canine species.
Transmission: The final host, the dog or fox, carries the eggs in their faeces that can then infect cattle through contaminated water or bedding. Unlike other protozoa that settle in the digestive system, these parasites migrate from the gut via
the bloodstream to the reproductive system where the consequences of infection will then be evident.
Symptoms: The main result of infection by this parasite is abortion that can occur as early as three months but usually occurs from five to six months. Other effects of the parasite include mummification and the birth of weak, underweight calves.
Treatment: No effective treatment is presently available.
Prevention: Protective measures include barriers around cattle feed to prevent contamination by infected dogs.