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An asymptomatic infection with Babesia sp. was diagnosed in an epidemiologic investigation of transfusion-acquired malaria. This is the seventh human piroplasmosis infection that has been reported in the literature.

The prevalence of microfilaremia among Indians in 13 Amazon Indian villages was determined by examining Giemsa-stained peripheral blood smears and preparations from peripheral blood lymphocyte cultures. Mansonella ozzardi was the only species found in the 601 persons tested. Prevalence was highly village-specific, ranging from 0% in four villages to as high as 93% among persons aged 10 years and older in others. Comparisons of the two methods showed that the concentration effect of the peripheral blood lymphocyte culture preparations allowed the detection of a greater number of microfilaria-positive persons, especially women and children with lower levels of parasitemia.

Over a 2-year period two cases of dermal leishmaniasis of special interest were recognized in Texas. The first occurred in 1972 in a 74-year-old woman who had residences in Dilworth and Gahzales, Gonzales County, and the other was in a 56-year-old man from Kenedy, Karnes County, in 1974. Both cases were biopsy- and culture-positive, and the second patient exhibited anti-Leishmania antibodies by indirect immunofluorescent antibody and direct agglutination tests. Epidemiologic investigation revealed no association between the two cases and suggested that both patients had acquired their infections locally in southern Texas. Moreover, serologic evidence of Leishmania infection was uncovered in a neighbor of the second case and in 3 dogs living nearby. Potential sylvatic reservoirs and arthropod vectors of the disease are resident in the area. Epidemiologic data suggest that dermal leishmaniasis is endemic in south-central Texas.

An indirect immunofluorescent test was used to determine antibody titers to Babesia microti in serum samples collected from 16 patients between 1 week and 1 year after the onset of illness. Titers rose to greater than or equal to 1:1,024 during the first few weeks of illness and then fell gradually to 1:16 to 1:256 over the next 5-6 months.

The prevalences of intestinal parasites among the residents of three South American Indian villages in the process of acculturation were compared with those found in earlier unpublished surveys in two newly contracted village.s Although one individual in an acculturating village harbored 11 different intestinal parasites, in general the average number of different parasitic species carried per person was somewhat higher in the newly contacted villages. Helminth egg counts, performed on direct smears of each specimen from one newly contacted village, were low. There were no sex-associated differences in prevalences. The overall prevalences, unadjusted for age, were among the highest recorded for Amerindians. No Taenia species were present. Balantidium coli was present in two acculturating villages, concomitant with the beginning of agricultural practices which include raising swine. No cases of moderate or severe protein-calorie malnutrition was observed in any of the villages during the surveys. These limited data provide a baseline for future comparisons and, perhaps, a glimpse into the past.

Serologic and parasitologic studies were done in El Salvador, C.A., from 1974-1978 to examine the reliability of the diagnosis of Entamoeba histolytica infection in an endemic area and to confirm the estimates of morbidity and mortality due to amebiasis. The results suggest that infection with E. histolytica is common, but the estimated prevalence is too high. Misdiagnosis occurring in hospital and public health laboratories was documented. Data collected from examining family members of persons with E. histolytica infection and disease indicate that most infections are asymptomatic, and support the hypothesis that estimates of morbidity and mortality rates are excessive.

Between 1969 and 1977, 14 persons with parasitologically confirmed Babesia microti infections and seven persons with antibody titers to B. microti greater than or equal to 1:1,024 were identified on Nantucket Island, Massachusetts. Nineteen of these 21 persons were interviewed. About half were permanent residents of Nantucket; the others spent most of their summers on the island. There were 12 women and seven men. Patients ranged in age from 23 to 86 years; all of those with parasitologically confirmed infections were at least 49 years old. Fifteen patients had illnesses characterized by fever, chills, myalgia and fatigue. Five reported being bitten by a tick from 7 to 28 days before the onset of illness. Most cases occurred during July or August. There appeared to be no association between B. microti infection and direct contact with wild or domestic animals or specific outdoor activities. The unusual age distribution of patients with parasitologically confirmed B. microti infections may result because older persons tend to have more severe illnesses and thus are more likely to come to medical attention.

An indirect immunofluorescent antibody test was used to detect antibody to Babesia microti in human sera. Nine patients from Nantucket Island, Massachusetts infected with B. microti had serum titers greater than or equal to 1,024. Of 84 control sera from New York City residents, 246 sera from patients with possible exposure to ticks, and 36 sera from patients with suspected or confirmed tick bites, none was reactive at titers of 1:16 or above. The within-test reproducibility was within one fourfold dilution in 95% of trials. Test-to-test reproducibility was within one fourfold dilution in 33% of trials and within two fourfold dilutions in 100% of trials. Although cross-reactions among infected patients' sera and antigens of B. argentina, B. equi, B. bigemina, Plasmodium vivax, P. falciparum, and P. brasilianum were common, titers were highest to the homologous antigen.