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INTRODUCTION
Babesiosis is caused by intraerythrocytic protozoan parasites of the genus Babesia that infect a wide range of domestic and wild animals and occasionally man. The disease is tick transmitted and distributed worldwide. The major economic impact of babesiosis is on the cattle industry and the two most important species in cattle, Babesia bovis and B. bigemina , will form the focus of this review.
Babes (1888) investigated disease outbreaks causing haemoglobinuria in cattle in Romania and was the first to describe piroplasms in the blood of cattle. He believed it to be a bacterium and named it Haematococcus bovis although the name was later changed to Babesia bovis (Angus, 1996). Shortly afterwards investigations by Smith and Kilborne (1893) in the United States of America demonstrated the causative organism of 'Texas Fever' (babesiosis) which they called Pyrosoma bigeminum (=Babesia bigemina ). They were the first to demonstrate transmission of a disease organism from an arthropod to a mammalian host when they showed the organism was transmitted by Boophilus annulatus to cattle (Smith & Kilborne, 1893). After the publication of this work, babesiosis was discovered in various parts of the world. Dr Sidney Hunt confirmed that bovine 'redwater' in Australia was identical in aetiology to Texas fever (Angus, 1996). In Argentina, Lignières (1903) described two forms of 'Tristeza' (babesiosis) 'forme A' and 'forme C'. These were later known as Babesia bigemina and B. argentina (=B. bovis ) and from descriptions of parasites, from cases of babesiosis described in Australia and USA in the late 1890s and early 1900s it is now believed that both B. bigemina and B. bovis were present in these also (Angus, 1996).
The confusing nomenclature of the bovine Babesia was thoroughly reviewed by Hoyte in the late 1960s and the four species of bovine Babesia which are now recognised are Babesia bovis (=B. argentina ; B. berbera ; B. colchica ), B. bigemina , B. divergens (=B. caucasica ; B. occidentalis ; B. karelica ) and B. major (Angus, 1996).
PARASITES AND DISTRIBUTION
The genus Babesia belongs to the phylum Apicomplexa, class Sporozoasida, order Eucoccidiorida, suborder Piroplasmorina and family Babesiidae (Levine, 1971, 1985; Allsopp et al . 1994). Criado-Fornelio et al . (2003) used the 18s rRNA...