Babesia Bovis

Synonyms: Haematococcus bovis, Piroplasma bovis, Babesiella bovis, Babesiella berbera (?).

Disease: Bovine babesiosis, piroplasmosis, redwater.

Hosts: Cattle, roe deer, stag.

Location: Erythrocytes.

Geographic Distribution: Europe, USSR, Africa.

Prevalence: This species is the most important cause of European babesiosis. It is common in many regions, but information on its true prevalence must await a decision as to whether B. berbera is a synonym and must also await new surveys in the light of the recent recognition that B. divergens is a separate species (see below).

Morphology: The trophozoites in the erythrocytes are piriform, round or irregular. Vacuolated "signet-ring" forms are especially common. B. bovis is a small form, with trophozoites measuring about 2.4 by 1.5 u (Davies, Joyner and Kendall, 1958).

Life Cycle: The life cycle was described above (p. 287). The tick vectors are Ixodes persulcatus in the USSR and, according to Simitch, Petrovitch and Rakovec (1955), Boophilus calcaratus and Rhipicephalus bursa in Europe. The tick ordinarily considered the vector in Europe is Ixodes ricinus, but the species it actually transmits may be B. divergens (see below). Transmission takes place thru the egg in all ticks, and from stage to stage in I. ricinus. Intra-uterine transmission has also been reported (Neitz, 1956).

Pathogenesis: The disease caused by B. bovis is similar to that caused by B. bigemina, but is not generally as severe. The incubation period is 4 to 10 days, and the first sign is a temperature of 104 to 106 F which usually lasts 2 to 3 days. Hemoglobinuria, anemia, icterus, diarrhea and rapid heart beat are present, and affected animals may die.

Immunity: Same as for B. bigemina, except that premunition does not last more than about 2 years. There is no crossimmunity between B. bigemina and B. bovis.

Diagnosis: Babesiosis due to B. bovis can be diagnosed on the basis of the history, clinical signs and presence of ticks together with identification of the parasites in stained blood smears. However, they are easily found only during the febrile period.

Treatment: In contrast to B. bigemina, B. bovis does not respond to trypan blue. Acaprin, acriflavine, phenamidine and berenil are effective, however; the same dosages are used as against B. bigemina.

Prevention and Control: Same as for B. bigemina.

Remarks: Recent work has reopened the question of synonymy in this and related species. B. berbera has generally been considered a separate species from B. bovis. It was thought to be the common small Babesia of North Africa, whereas B. bovis was thought to be primarily European. However, Simitch and Nevenitch (1953) and Simitch, Petrovitch and Rakovec (1955) found a Babesia in Yugoslavia just across the Danube River from the area where Babes (1888) has described B. bovis which corresponded completely with B. berbera. The latter authors also found another, morphologically different species in Yugoslavia which corresponded completely with B. divergens. This latter species had originally been described in England by M'Fadyean and Stockman (1911), and had generally been considered a synonym of B. bovis. Simitch, Petrovitch and Rakovec (1955) concluded that B. berbera is a synonym of B. bovis and that it occurs in North Africa and southern Europe in association with Boophilus calcaratus and Rhipicephalus bursa. They also concluded that the species which occurs in western and central Europe in association with Ixodes ricinus is not B. bovis, but B. divergens.

Davies, Joyner and Kendall (1958) compared a British strain of Babesia with a strain of B. bovis sent to them from Yugoslavia, and concluded that they were indeed morphologically different and that the correct name for the British strain was B. divergens.

Sergent, Donatien and Parrot (1954) felt that final proof as to the identity of B. bovis and B. berbera must await crossimmunity experiments. I am retaining both names for the present, with the strong suspicion that they are synonymous.