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Biomedical subjects

J L Benach

Publications and source records attributed to J L Benach.

At least 109 records · Page 6Linked to original sources
PubMed1984

Incidence and cumulative frequency of endemic Lyme disease in a community.

We conducted an epidemiological study of the cumulative frequency and incidence of Lyme disease in a summer community on Fire Island, New York, an area endemic for the disease. Fifteen (7.5%) of 200 persons studied in the community in 1982 reported a history of Lyme disease. An indirect immunofluorescent antibody assay showed that seventeen (9.7%) of 176 persons had serological evidence of exposure to the Lyme spirochete, including six of the 15 persons with a history of Lyme disease. Seven (0.7%-1.2%) of 600-1,000 persons in the community developed clinical symptoms and serological evidence of Lyme disease during the summer season, including two (1%) of the 200 persons in the study group. Four (3.1%) of 129 persons who had sera collected before and after the summer season demonstrated fourfold or greater rises in IgG antibody titers to the Lyme spirochete, including 2 (1.6%) persons without symptoms of Lyme disease. We conclude that the incidence of Lyme disease can be appreciably higher in endemic areas than previously recognized and that subclinical or inapparent seroconversion may occur after infection.

Adolescent↗
PubMed1984

Interactions of phagocytes with the Lyme disease spirochete: role of the Fc receptor.

The phagocytic capacity of murine and human mononuclear and polymorphonuclear phagocytes (including peripheral blood monocytes and neutrophils), rabbit and murine peritoneal exudate cells, and the murine macrophage cell line P388D1 against the Lyme disease spirochete was studied. All of these cells were capable of phagocytosing the spirochete; phagocytosis was measured by the uptake of radiolabeled spirochetes, the appearance of immunofluorescent bodies in phagocytic cells, and electron microscopy. Both opsonized and nonopsonized organisms were phagocytosed. The uptake of opsonized organisms by neutrophils was blocked by a monoclonal antibody specific for the Fc receptor and by immune complexes; these findings suggested that most phagocytosis is mediated by the Fc receptor. Similarly, the uptake of opsonized organisms by human monocytes was inhibited by human monomeric IgG1 and by immune complexes. These results illustrate the role of immune phagocytosis of spirochetes in host defense against Lyme disease.

Animals↗
PubMed1983

Natural Distribution of the Ixodes dammini spirochete.

Spirochetes believed to be the cause of Lyme disease were isolated from white-footed mice and white-tailed deer, the preferred natural hosts of Ixodes dammini, the tick vector. Evidence suggests that deer act as a reservoir of the disease and provide an overwintering mechanism for both spirochetes and adult ticks. Some tick larvae may acquire the spirochete by transovarial passage and the nymphal stage may transmit the disease to humans.

Animals↗
PubMed1983

Spirochetes isolated from the blood of two patients with Lyme disease.

We isolated spirochetes from the blood of 2 of 36 patients in Long Island and Westchester County, New York, who had signs and symptoms suggestive of Lyme disease. The spirochetes were morphologically similar and serologically identical to organisms recently found to infect lxodes dammini ticks, which are endemic to the area and have been epidemiologically implicated as vectors of Lyme disease. In both patients, there was a rise in specific antispirochetal antibodies in paired specimens of serum. We conclude that the l. dammini spirochete has an etiologic role in Lyme disease.

Adult↗
PubMed1982

Human babesiosis. Clinical and therapeutic considerations.

During a two-month period, six patients from eastern Long Island were identified as having Babesia microti infection. Diagnosis was based on characteristic blood smears, hamster inoculation, or both. Symptom duration ranged from 19 to 24 days in five patients. The sixth patient, who had previously undergone splenectomy, had a more severe and prolonged illness. No specific therapy was administered to five patients. The patient who had had a splenectomy was treated with chloroquine, quinine, pentamidine, and exchange transfusions. There were no deaths. It appears that most cases of human B microti infection can be effectively managed with symptomatic and supportive care.

Aged↗
PubMed1982

Lyme disease-a tick-borne spirochetosis?

A treponema-like spirochete was detected in and isolated from adult Ixodes dammini, the incriminated tick vector of Lyme disease. Causally related to the spirochetes may be long-lasting cutaneous lesions that appeared on New Zealand White rabbits 10 to 12 weeks after infected ticks fed on them. Samples of serum from patients with Lyme disease were shown by indirect immunofluorescence to contain antibodies to this agent. It is suggested that the newly discovered spirochete is involved in the etiology of Lyme disease.

Animals↗
PubMed1982

Immunoresponsiveness in acute babesiosis in humans.

Immunoresponsiveness in patients with acute babesiosis was characterized. Lymphocyte subpopulations, mononuclear cell responses to nonspecific mitogens, and serum immunochemical values were studied in patients during acute babesiosis and after recovery (four to 40 months), controls, and seropositive individuals. Serum studies were also carried out retrospectively on stored sera from patients with babesiosis. Mean and differential lymphocyte counts and percentages of B lymphocytes were higher than in controls in patients with acute babesiosis, and levels of T lymphocytes bearing the IgG Fc receptor (T gamma) were significantly (P less than 0.01) elevated. Responses to nonspecific mitogens were suppressed during acute babesiosis. Levels of serum IgG and IgM and Clq binding were significantly increased whereas C3 and C4 levels and hemolytic activity were suppressed in acute-phase sera. The apparent paradox of an increased T suppressor/cytotoxic population in the presence of evidence of increased in vivo lymphocyte function is discussed in terms of the heterogeneity of the T gamma subpopulation.

Adult↗
PubMed1982

Glucan as an adjuvant for a murine Babesia microti immunization trial.

A vaccination protocol against murine Babesia microti infection, using glucan, a beta-1,3-glucopyranose derivative of yeast cell walls, and glutaraldehyde-fixed infected erythrocytes was evaluated. BALB/c mice were immunized intravenously four times at 2-day intervals with 2 X 10(8) fixed infected erythrocytes with and without glucan (0.45 mg). The mice were challenged 2 weeks after the last immunization with 10(8) viable infected erythrocytes. Peak parasitemia was significantly reduced (8.9 +/- 1.0%; P less than 0.001) in glucan-immunized mice as compared with nonimmunized controls (41.2 +/- 1.4%), glucan-treated controls (31.7 +/- 2.5%; P less than 0.05), or mice which received fixed infected erythrocytes without glucan (21.0 +/- 1.2%; P less than 0.01). Humoral and cellular immunity to B. microti was evaluated before challenge by measuring antibody titers and splenocyte blastogenic responses to B. microti antigens. The in vitro cellular response was inversely correlated with mean peak parasitemia (P less than 0.05). These observations demonstrate that glucan is an effective adjuvant in enhancing immunity to murine babesiosis.

Adjuvants, Immunologic↗
PubMed1980

Rocky Mountain spotted fever in dogs.

Infection with rickettsiae of the spotted fever group was clinically and serologically diagnosed in four dogs from two households on Long Island. In two dogs, clinical signs included high fever (to 40.5 C), abdominal pain, lethargy, depression, anorexia, and nystagmus. One of these dogs had conjunctivitis and petechial hemorrhages in the oral mucous membranes. The third dog initially had high fever, evidence of abdominal pain, anorexia, and depression. The fourth dog appeared clinically normal. Clinical signs disappeared following treatment with tetracycline given orally.

Animals↗
PubMed1980

Serosurvey for human babesiosis in New York.

Healthy individuals at high risk of exposure to ticks were surveyed to determine the prevalence and incidence of asymptomatic babesiosis on Shelter Island, New York, during a single transmission season. Paired sera obtained in June and October 1978 were tested for antibodies to Babesia microti by indirect immunofluorescence. Point prevalence values of 4.4% in June and 6.9% in October were obtained. Six of 102 persons tested in both months showed at least a fourfold rise in titer of antibodies to B. microti (an incidence of 5.9% for the season). None of 300 serum specimens obtained from the New York City metropolitan area had significant titers to B. microti. Of the six persons who seroconverted, four gave a history of tick bite during the transmission season; three of the four persons claimed to recognize the tick as an Ixodes dammini, the vector for B. microti.

Adolescent↗
PubMed1979

Immunological relationships of Long Island isolates of Babesia microti.

Studies to detect strain differences among two rodent-derived and one human-derived Babesia microti isolates from Long Island were undertaken, using various methods. Superinfection experiments using the homologous and heterologous isolates showed cross-protection. All hamsters were resistant to superinfection challenges of increasing dosages of both the homologous and heterologous isolates. Attempts to infect other laboratory animals with the Long Island isolates of B. microti were successful in intact and splenectomized Sprague-Dawley rats and questionable in Swiss mice. Nylar and CFW mice as well as CFW and Wistar intact and splenectomized rats were refractory to B. microti isolates from Long Island. Indirect fluorescence tests using convalescent sera from six Long Island cases of babesiosis showed no titer differences with tests using the three Long Island antigens as well as the Gray strain antigens. The rise of hamster IgG anti-B. microti antibody was followed by indirect immunofluorescence done at different parasitemia levels. The IgG antibody in hamsters was detected early in the course of infection, rose rapidly concurrent with increasing parasitemia, and became stable at high titers for the duration of the infection. IgG antibody titers were unaffected by homologous superinfection challenges.

Animals↗
PubMed1978

Babesiosis in Long Island. Host-parasite relationships of rodent- and human-derived Babesia microti isolates in hamsters.

The effects of splenectomy and size of inoculum on response of hamsters to three isolates of Babesia microti (two rodent- and one human-derived) from Long Island were studied. Splenectomy of hamsters did not enhance susceptibility to the rodent isolates of B. microti at a dosage of 5 X 10(7) parasites. Larger parasite inocula produced shorter prepatent periods and slightly shorter duration of infection in intact hamsters. Inoculum size was not contributory to mortality of hamsters or to pathogenesis. Hamsters showed profound anemia with depressed hematocrit and hemoglobin values and erythrocyte counts. Moderate leucocytosis was seen just prior to peak parasitemia, with immature polymorphonuclear cells predominating. Infections in hamsters lasted for 14--17 weeks. As determined by the parameters studied, the three isolates appear to be identical.

Animals↗
PubMed1977

Changing patterns in the incidence of Rocky Mountain Spotted Fever on Long Island (1971-1976).

Clinical data from 124 Rocky Mountain Spotted Fever (RMSF) cases submitted by Long Island physicians and hospitals were compiled for the six-year period 1971-1976. This information was subsequently compared to two parameters: first, the geographic distribution of human cases and rickettsia-infected Dermacentor variabilis (Say), and, secondly, the human population dynamics in Long Island towns since 1950. Despite an overall decline in the rate of suburbanization and population growth, cases of RMSF have increased significantly not only in eastern towns where RMSF has been endemic, but also in well-established western towns where recent population increases have been negligible. Phenomena associated with suburbanization, primarily the association of domestic and sylvan animals and their exposure to infected vector populations, may be instrumental in explaining the increased transmission of RMSF.

Adolescent↗