We describe babesiosis transmitted by transfusion. The infected blood donor was identified and a minimum period of infectivity of the donor's blood was established. We report a new modality for chemotherapy consisting of quinine plus clindamycin, and a new endemic focus for this zoonosis on Fire Island, New York. There are insufficient data to establish a reasonably safe period after which visitors and residents of Babesia-endemic foci can become blood donors. Screening of such persons by a rapid serologic test, such as the ELISA or immunofluorescent antibody tests, is suggested.

L6E9 rat myoblasts were infected in tissue culture with the myotropic Brazil strain of Trypanosoma cruzi. The effect of parasite infection on the ability of myoblasts to differentiate into myotubes was studied. Both morphological and biochemical differentiation were found to be profoundly affected by parasitic infection in a dose-related fashion. Evidence is presented to suggest that infected myoblasts can no longer differentiate. Differentiation, once underway, seemed unaffected by the parasitic infection; biochemical markers of differentiation remained intact.Chagas disease, caused by the protozoan hemoflagellate Trypanosoma cruzi, is a major public health problem in Latin America (1). The disease is characterized by an acute phase during which fever, myocarditis, meningoencephalitis, and hepato-splenomegaly may occur. Cardiomyopathy and disturbances of the autonomic nervous system characterize the chronic stage (1-3). At present, the mechanism responsible for the observed tissue damage is unclear, but there is suggestive evidence that chronic chagasic myocarditis may be, in part, secondary to autoimmune phenomena (4-7). Polymyositis, often reported in pathological studies (6,8,9), is usually overshadowed by the more clinically evident cardiac disease.Skeletal muscle is readily infected by T. cruzi and has been used to propagate trypomastigotes in vitro (10-12). There is no information, however, on the effects of T. cruzi on some of the fundamental events in the myogenesis of skeletal muscle. As the kinetics of the differentiation of myoblasts to form myotubes and biochemical differentiation has been extensively studied in the L6E9 rat myoblast line (13), we have used this muscle cell line to assess the effects of T. cruzi infection on both morphological and biochemical parameters of in vitro muscle differentiation.The findings reported herein strongly suggest that infection of muscle cells by T. cruzi profoundly affects myogenesis. MATERIALS AND METHODSCell Lines and Culture Conditions. L6E9 cells (13) were maintained as proliferating undifferentiated myoblasts in Dulbecco's modified Eagle's medium (DME medium) (GIBCO) supplemented with 20% fetal calf serum (GIBCO)-so-called "growth medium." They were induced to terminally differentiate and fuse to form multinucleate myotubes by transfer into "differentiation medium" consisting of DME medium with either 10% horse serum (GIBCO) or 2% fetal calf serum/2.5% horse serum. Previous work has established that myoblasts become irrevocably "committed" to differentiate after 24 hr in this medium (13). All cells were maintained at 37TC in a humidified atmosphere containing 7% CO2.Trypanosomes. The myotropic Brazil strain of T. cruzi was serially syringe-passaged in C3H mice. When the parasitemia reached 107 parasites per ml a sterile cardiac puncture was performed and the heparin-treated blood was introduced into 24-hr-old LEq cell cultures and allowed to invade host cells. After 18 hr of incubation, the remaining free-swimming trypanosomes were removed, myobl...

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A case of babesiosis in an asplenic individual is reported. A course characterized by fever, haemolysis, hepatitis, depressed mental status and non-cardiac pulmonary oedema was observed. Studies performed on the patient's lymphocytes revealed profound depression in mitogenic responses during her acute disease which returned to normal with recovery. Serum factor(s) were implicated in causing these changes. Review of the literature on babesiosis in asplenic hosts revealed European patients with disease caused by bovine species of Babesia are at significantly higher risk of a fatal outcome than North Americans with disease caused by murine species.

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