Piroplasmida

Piroplasmida is a class of parasitic protozoa that belongs to the phylum Apicomplexa. These organisms are commonly found in the blood cells of vertebrates, including mammals, birds, and reptiles. Piroplasmida is known for causing a disease called piroplasmosis, which can have severe consequences for the infected host.

Taxonomy

Piroplasmida is a class within the phylum Apicomplexa, which also includes other parasitic protozoa such as Plasmodium, the causative agent of malaria. Within the class Piroplasmida, there are two main families: Babesiidae and Theileriidae. The Babesiidae family includes genera such as Babesia and Theileria, while the Theileriidae family includes the genus Theileria.

Morphology and Life Cycle

Piroplasmida organisms have a complex life cycle that involves both vertebrate and invertebrate hosts. In the vertebrate host, the parasites reside within the red blood cells, where they undergo asexual reproduction. This results in the formation of merozoites, which can further invade other red blood cells or differentiate into sexual forms called gametocytes.

When a tick or other blood-feeding arthropod feeds on an infected vertebrate, it ingests the gametocytes along with the blood. Within the tick's gut, the gametocytes undergo sexual reproduction, resulting in the formation of zygotes. These zygotes then develop into motile forms called kinetes, which migrate to the salivary glands of the tick. When the tick feeds on another vertebrate, it injects the kinetes into the host's bloodstream, completing the transmission cycle.

Pathogenesis

Piroplasmida parasites can cause significant damage to their vertebrate hosts. The parasites invade and multiply within the red blood cells, leading to their destruction and subsequent anemia. The host's immune response to the infection can also contribute to tissue damage and inflammation.

The severity of piroplasmosis varies depending on the species of the parasite and the host's immune response. In some cases, the infection can be mild or even asymptomatic. However, in other cases, it can lead to severe symptoms such as fever, lethargy, anemia, jaundice, and organ failure. Piroplasmosis can be particularly dangerous in young or immunocompromised animals.

Diagnosis and Treatment

Diagnosing piroplasmosis typically involves microscopic examination of blood smears, where the presence of piroplasmida parasites can be observed within the red blood cells. Molecular techniques such as polymerase chain reaction (PCR) can also be used for more accurate detection and identification of the parasite species.

Treatment of piroplasmosis usually involves the administration of antiprotozoal drugs such as imidocarb dipropionate or diminazene aceturate. Supportive care, including blood transfusions and fluid therapy, may also be necessary in severe cases.

Prevention and Control

Preventing piroplasmosis primarily involves controlling the tick population and minimizing exposure to infected ticks. This can be achieved through regular tick control measures, such as the use of acaricides and tick repellents on both animals and their environment. Vaccines against specific piroplasmida species have also been developed for certain animal species.

See Also

• Apicomplexa
• Babesia
• Theileria
• Piroplasmosis

References

1. Uilenberg, G. (2006). Babesia—a historical overview. Veterinary Parasitology, 138(1-2), 3-10. 2. Criado-Fornelio, A., Martinez-Marcos, A., Buling-Sarana, A., Barba-Carretero, J. C. (2003). Molecular studies on Babesia, Theileria and Hepatozoon in southern Europe. Part I. Epizootiological aspects. Veterinary Parasitology, 113(3-4), 189-201. 3. Shkap, V., Pipano, E., & Fish, L. (2002). Vaccination of cattle against Theileria annulata using a soluble parasite antigen preparation. Veterinary Parasitology, 105(4), 307-323.