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Biomedical subjects

G R Healy

Publications and source records attributed to G R Healy.

At least 19 recordsLinked to original sources
PubMed1988

Variable infectivity of human-derived Giardia lamblia cysts for Mongolian gerbils (Meriones unguiculatus).

To determine whether gerbils can be used as a suitable animal model for giardiasis, we attempted to infect Mongolian gerbils with cysts of Giardia lamblia isolated from the stools of 10 humans with symptomatic and asymptomatic giardiasis. We obtained 100% infection with one isolate (CDC:0284:1), as evidenced by the presence of numerous trophozoites in the intestines of the gerbil and cysts in the feces. Cysts from four patients were not infective, while cysts from the other five patients produced infections in 11 to 75% of the animals. On the basis of these and other experiments, we concluded that (i) only certain isolates of human G. lamblia infect gerbils, colonize the intestine, and complete their life cycle by undergoing differentiation into cysts; (ii) the infection could last for about 39 days, but the animals excreted maximum numbers of cysts on about day 13 postinfection; (iii) the pattern of cyst excretion was irregular, and some gerbils, like humans, excreted cysts intermittently; (iv) the minimum number of cysts needed to establish an infection in 50% of the gerbils was 100; and (v) only certain strains retained the ability to infect gerbils even after repeated animal passage.

Animals↗
PubMed1985

Hepatocellular carcinoma simulating amebic liver abscess: report of a case and analysis of current diagnostic methods.

Radiological and serological tests are valuable tools commonly used in diagnosing amebic liver abscess. The limitations in sensitivity and specificity of the various imaging procedures should be recognized in order to avoid misinterpretation of test results. Serodiagnostic methods present potential pitfalls primarily because of their frequent inability to differentiate previous disease from active infection, and must therefore be interpreted carefully.

Adult↗
PubMed1979

Babesia infections in man.

Only recently has it been recognized that hemotropic animal parasites of the genus babesia are also human pathogens. Similar to malaria in both symptoms and laboratory findings, acute babesiosis generally results in self-limited illness, but it can be fatal in the asplenic patient. The widely disseminated vector tick, Ixodes dammini, can transmit infection at each stage of its development, larva and nymph as well as adult.

Adult↗
PubMed1979

Epidemiologic studies among Amerindian populations of Amazonia. II. Prepvalence of Mansonella ozzardi.

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.

Adolescent↗
PubMed1979

Experimental Babesia microti infections in non-splenectomized Macaca mulatta.

Eight non-splenectomized Macaca mulatta were inoculated intravenously with strains of Babesia microti that originally were isolated from 2 human cases of babesiosis and then were maintained in hamsters in the laboratory. Patent infections developed in 7 animals with peak parasitemias of 496 to 3,906 organisms/mm3 blood. Prepatent periods ranged from 15 to 46 days. Parasitemia persisted for at least 90 days in all animals and in one, organisms were still present 559 days after inoculation.

Animals↗
PubMed1978

Retrospective identification of Acanthamoeba culbertsoni in a case of amoebic meningoencephalitis.

Acanthamoeba culbertsoni was identified retrospectively in a case of amoebic meningoencephalitis, previously reported by Jager and Stamm (Lancet, 2, 1343, 1972). This is the second report of this species causing secondary infection in man. Positive results were obtained only with anti-A. culbertsoni sera when the brain sections were stained by the indirect immunofluorescence antibody test with various antisera produced against different Acanthamoeba species. Antiserum raised against purified plasma membranes of A. culbertsoni showed once more its highly specific diagnostic value.

Adult↗
PubMed1978

Babesia microti infection in man: evaluation of an indirect immunofluorescent antibody test.

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.

Animals↗
PubMed1978

Amebiasis: epidemiologic studies in the United States, 1971-1974.

Seven investigations of suspected foci of amebiasis between October 1971 and June 1974 lead to three conclusions. (1) A number of laboratories have vastly overdiagnosed amebiasis and have reported leukocytes in stools as Entamoeba histolytica. Two laboratories found to be in error were in community hospitals, and one was at a teaching hospital associated with a medical school and a school of public health. These three laboratories had been diagnosing more than 1200 cases of amebiasis a year for 20 years. (2) When amebiasis does occur, it is likely to be misdiagnosed. In one outbreak with four cases and three deaths, amebiasis was not diagnosed until two patients had died and another was critically ill. Sporadic cases may be mistakenly diagnosed as ulcerative colitis and inappropriately treated with steroids. (3) Foci of endemic amebiasis continue to exist in the United States, both in institutions and in noninstitutional settings.

Amebiasis↗
PubMed1978

Intraerythrocytic parasitosis in humans with Entopolypoides species (family Babesiidae). Association with hepatic dysfunction and serum factors inhibiting lymphocyte response to phytohemagglutinin.

We have observed two cases of human infection with intraerythrocytic protozoa. The organisms appeared to be in the Entopolypoides group, which had not previously been associated with human infection. One patient was asplenic. Both patients had hepatic dysfunction, and their serum samples contained blocking factors that interfered in vitro with the stimulation of normal lymphocytes by phytohemagglutinin. It appears that in humans, as well as in experimental animals, host factors are important in resistance to infection by intraerythrocytic parasites. These factors include the presence of a spleen and cell-mediated and humoral immunities. Possibly similar infections will be observed in patients with other impairments of T-cell function, such as those induced by malignancy, thymic dysfunction, or immunosuppressive drugs.

Adult↗
PubMed1977

Human babesiosis on Nantucket Island. Clinical features.

Between 20 July and 15 Octoboer 1975, five cases of human infection with Babesia microti were diagnosed on Nantucket Island, Massachusetts. The illness was characterized by fever, drenching sweats, shaking chills, myalgia, arthralgia, extreme fatigue, and a mild-to-moderate hemolytic anemia. None of the patients had a history of splenetomy. Although all patients responded symptomatically to treatment with oral chloroquine phosphate, parasitemia and fatigue frequently persisted for several weeks to months.

Aged↗
PubMed1977

A communitywide outbreak of giardiasis with evidence of transmission by a municipal water supply.

Three hundred fifty residents of Rome, New York, had laboratory-confirmed cases of giardiasis between 1 November 1974 and 7 June 1975. A random household survey showed an overall attack rate for giardiasis (defined as a diarrheal illness of 5 days or more) of 10.6%. A significant association was discovered between having giardiasis and using city water and between having illness and drinking 1 or more glasses of water a day. The presence of human settlements in the Rome watershed area suggested that the water supply could have been contaminated by untreated human waste. The infectivity of municipal water was confirmed by producing giardiasis in specific pathogen-free dogs fed sediment samples of raw water obtained from an inlet of a city reservoir. A microscopic examination of the water sediments uncovered a Giardia lamblia cyst in one sample. This was the first time that a G. lamblia cyst has been found in municipal water in an epidemic and the first time that such water has been shown to infect laboratory animals.

Animals↗
PubMed1976

Human babesiosis: reservoir in infection on Nantucket Island.

Examination of blood films from six species of rodents and lagomorphs on Nantucket Island disclosed infections with Babesia microti in all of five Microtus pennsylvanicus (field mice) and 31 of 39 Peromyscus leucopus (white-footed or deer mice). Six human cases of clinical babesiosis have recently been diagnosed on the island.

Animals↗