Acute lymphatic filariasis in an American traveler.

Acute lymphatic filariasis developed in an American traveling recreationally to Asia. The illness was characterized by fatigue, eosinophilia, and lymphedema of the arm and chest wall, but no lymphangitis, lymphadenitis, or pain. Complete resolution occurred over 1-2 years. We discuss this syndrome and describe the use of new diagnostic tests in its diagnosis and management.

Low Toxoplasma antibody prevalence in serologic surveys of humans in southern Mexico.

Antibody prevalence to Toxoplasma gondii among residents of a Pacific coastal region of Oaxaca State, Mexico is among low rates reported worldwide. From 60 small, rural communities, 3229 persons from ages 6 months to over 70 years provided blood specimens that were stored on filter papers. 124 (3.8%) of the eluates were seropositive (positive titer greater than 1:256) in the indirect hemagglutination test, and 43 (1.3%) had titers greater than 1:1024. Seropositive rates increased by age group and females were positive twice as often as males. There was no difference in rates for persons who lived at sea level, compared to those who lived between 600 and 1800 meters. In two small communities in which the number of persons tested were a large percentage of the total population, seropositive rates were 1.0 and 1.9%, respectively. The probable explanation for these low rates is the near absence of cats and paucity of meat in the diet. By contrast, sera tested from 479 persons living about 150 km to the east in the coastal, urban towns of Tehuantepec of Salina Cruz showed positive reactions among 122 (125.5%), and 71 (14.8%) had titers less than 1:1024. These people had a higher standard of living, more meat in their diet, and a few cats.

Use of a nomogram to quantitate plasma dilutions for serological testing following blood collection in capillary tubes.

A technique for the processing and quantitation of small volumes of plasma collected in heparinized capillary tubes is presented using a nomogram that determines the final amount of diluent needed for variable volumes of plasma.

Enzyme-linked immunosorbent assay for the diagnosis of cerebral cysticercosis.

Central nervous system cysticercosis is common in countries where Taenia solium occurs in pigs and the level of hygiene and sanitation is low. The clinical presentation may include epileptic seizures, focal neurological deficits, hydrocephalus, or aseptic meningitis. The disease is frequently seen in California residents of Hispanic origin. It sometimes occurs in whites from homes that employ Hispanic cooks. Diagnosis is often difficult. Computerized tomography scan and brain biopsy are the most reliable diagnostic procedures, but each has its limitations. We have found that a radioimmunoassay improves our diagnostic capability, and more recently we have adapted this to an enzyme-linked immunosorbent assay that is equally sensitive and specific and, in addition, obviates the need for radioactive materials. Details of the enzyme-linked immunosorbent assay procedure and its application to the diagnosis of central nervous system cysticercosis form the basis of this report.

Acquired immunity in B cell-deficient mice to challenge exposure following primary infection with Schistosoma mansoni.

Mice were made B cell-deficient by injections of globulin prepared from goat antimouse mu-chain serum. Anti-mu globulin was administered throughout the experiments (18 or 23 weeks). B cell deficiency was determined at the time of assay of worm burden levels (7 weeks after challenge with Schistosoma mansoni) by quantitation of serum IgM and IgG, by assaying the specific antibody response to cercarial and adult worm antigens in enzyme-linked immunosorbent assay and by histologic examination of the spleen and mesenteric (regional) lymph nodes. Four-week-old mice were exposed to S. mansoni and 8 weeks later were challenged with a second exposure. The B cell-deficient mice developed a degree of resistance (79%) similar to that of the intact controls (81%). The IgM and IgG levels of the B cell-deficient mice were markedly suppressed. Follicular development was not detected in their lymph nodes; but in the spleen of some animals clusters of cells morphologically similar to B cells were observed peripheral to a central T cell-like area. B cell-deficient mice developed schistosome egg granulomas comparable to those of the intact controls. Control animals developed an antibody response with titers of 1:64 to 1:1,024 against cercarial and adult worm antigens; B cell-deficient animals were nonreactive in these assays. The data suggest that specific antibody does not play a major role in resistance acquired within 8 weeks as a result of a primary infection in murine schistosomiasis.

Gross and histological studies of immediate, Arthus, and delayed skin test responses to schistosome antigen, and of delayed response to ubiquitous antigens in Egyptians.

Gross studies of skin reactions to adult antigen of Schistosoma mansoni were made on 156 hospitalized patients with schistosomiasis and 114 subjects from the nonendemic area of Hurghada in Egypt. Wheal areas equal to or greater than 1.0 cm2 indicated a positive immediate (15-min) reaction to adult worm antigen; the criterion of positivity for both 24-hour and 48-hour delayed reactions was an area of induration equal to or greater than 0.6 cm2. Immediate reactions with adult worm antigen were observed in 99% of the patients with schistosomiasis and 11% of the subjects from Hurghada: the percentages with delayed reaction were 58% and 2%, respectively. Biopsies of skin test sites at various intervals after antigen injection were done on 87 individuals. Eosinophilic and mononuclear infiltrates were characteristic of immediate and delayed skin responses, respectively. Biopsies from 22 patients with marked skin reactions 5 hours after antigen injection showed that a neutrophilic response indicative of Arthus reactivity was present in only 18. Thus, Arthus reactivity could not be determined on gross appearance alone. The studies did not show any evidence of delayed basophilic hypersensitivity to schistosome antigen. Immunofluorescent studies on a small number of biopsies suggested that a late phase (5-hour) reaction due to IgE may occur in some patients. Delayed reactivity to mumps and/or monilia skin test antigens was observed in 91% of Egyptians in a nonendemic area of schistosomiasis. Delayed hypersensitivity to PPD was detected in 44% of the same group.

Epidemiologic studies among Amerindian populations of Amazonia. III. Intestinal parasitoses in newly contacted and acculturating villages.

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.

Adoptive transfer of protective immunity in experimental schistosomiasis in the mouse.

Passive transfer of immune serum alone did not confer protection to recipient mice irrespective of the routes of serum transfer or cercarial challenge of Schistosoma mansoni. Mice that received both sensitized cells and immune serum were protected against challenge by subcutaneous injection of cercariae but not by percutaneous exposure. The immune serum could be transferred as late as 8 days after subcutaneous challenge, suggesting that the protection was afforded in part by a late parasite killing mechanism which functions after the schistosomula have migrated through the lungs.