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Biomedical subjects

S Fisher-Hoch

Publications and source records attributed to S Fisher-Hoch.

7 recordsLinked to original sources

Serum antibodies to structural proteins of Hantavirus arise at different times after infection.

An enzyme-linked immunosorbent assay (ELISA) was developed for the quantification of serum antibodies against group-specific epitopes of the glycoproteins (G1, G2) and nucleoprotein (NP) of the genus Hantavirus. This assay was used to study the kinetics of the development of serum antibodies after natural infection with Puumala-like virus in humans. To this end a panel of 34 serum samples collected from individuals at different times after natural infection was tested by the ELISA. The samples were also tested for specific IgM and IgG levels against Puumala-like virus, which provided confirmatory data about the presumed timing of infection. It was shown that serum antibodies against the G1 epitope were present in the acute and early convalescent period just before antibodies to the NP epitope could be demonstrated. In contrast, antibodies to two G2 epitopes were present not earlier than in the convalescent and late convalescent period. Since all these categories of antibodies seem to persist for long periods, antibodies against the G1 epitope and the NP epitope may be of specific diagnostic value. Furthermore, levels of G1-specific antibodies and antibodies to either NP or G2 may allow estimation of the time elapsed following initial infection.

Antibodies, Viral

Virus zoonoses and their potential for contamination of cell cultures.

Silent virus infections of laboratory animals present a human health hazard, from direct exposure and from contamination of biological products for human use. Here we report two recent examples. In 1989, an outbreak of lymphocytic choriomeningitis virus (LCMV) infections was recognized among workers at a cancer research center after an animal caretaker developed viral meningitis. Investigation revealed that multiple tumor cell lines at the facility were infected with LCMV, as were research animals injected with these cell lines. Of 82 workers tested, eight (10%) were found to have been infected. The infected workers were more likely than other animal handlers to report handling athymic (nude) mice (p less than .0.007). The number of nude mice used in this facilty had increased five-fold in the previous year, possibly explaining the timing of the outbreak. This is the first reported LCMV outbreak since 1975, and the first to implicate nude mice as a source of human LCMV infections. In November 1989 and January 1990, infections caused by two distinct Ebola-like filoviruses were discovered in non-human primates at quarantine facilities in Virginia and Pennsylvania. Although 22 persons were considered to have high- or medium-risk exposures for Ebola infection, no Ebola-compatible illnesses occurred. One of the medium-risk persons had Ebola IgG antibodies confirmed by IFA and Western blot. Rigorous use of barrier precautions may have limited exposure and infection with these filoviruses. In February 1990, new groups of filovirus-infected monkeys were identified in Virginia and in Texas. Seroconversion occurred in four animal handlers, including one to very high titer, but again no illness was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Hematologic dysfunction in Lassa fever.

Lassa fever is widespread in West Africa, where the case fatality is about 16% in hospitalized adult patients. The clinical course is highly variable, with a few patients developing severe disease with bleeding, adult respiratory distress syndrome, encephalopathy and hypovolemic shock. We studied 70 patients admitted with suspected Lassa fever to a hospital in Sierra Leone, West Africa. Fourteen patients classified as having severe Lassa fever on the basis of serum aspartate amino transferase (AST) greater than 150 IU/L or viremia of greater than 10(3.6) tissue culture infective dose (TCID) 50/ml were found to have statistically significantly depressed lymphocyte counts when compared with patients with mild Lassa fever (AST less than 150 IU/L or viremia, less than 10(3.6)TCID50/ml), (P less than 0.0001) and with febrile control patients, in whom Lassa infection had been excluded by laboratory criteria (P less than 0.0008). Maximum depression occurred a mean of 10.9 days post onset. Patients with severe Lassa fever also had moderate thrombocytopenia, which was statistically significant when compared with febrile control patients (P less than 0.0003) and this occurred a mean of 10.8 days postonset. The most significant changes were in platelet function, which was markedly depressed in patients with severe Lassa fever (P less than 0.0035 in response to ADP and P = 0.0081 for collagen) when compared with patients with mild Lassa fever, and when compared with febrile controls, (P = 0.0013 for ADP and P less than 0.00001 for collagen). This abnormality was usually maximal on admission to hospital, and probably is an early event, preceding hospitalization in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans

Legionnaires' disease in a transplant unit: isolation of the causative agent from shower baths.

Legionnaires' disease was diagnosed in two patients in a transplant unit, both patients having occupied the same postoperative cubicle shortly before onset of their illnesses. Legionella pneumophila was found in water taken from the cubicle shower bath and from other showers in the unit. To eradicate the legionellae, the water supply was treated with chlorine, but this had only a temporary effect.

Adult

Identification of a clinical isolate as Legionella pneumophila by gas chromatography and mass spectrometry of cellular fatty acids.

Culture of a bronchial aspirate from an immunosuppressed patient with severe pneumonia yielded a growth of filamentous poorly staining gram-negative rods. Fluorescence with Legionella pneumophila direct fluorescein-isothiocyanate conjugate was equivocal. Gas-liquid chromatography (GLC) and GLC/mass-spectrometry (GLC-MS) of the cellular fatty acids of the isolate confirmed that the organism was L. pneumophila. GLC and GLC-MS constitute a rapid and definitive method for identification of L. pneumophila isolates.

Bacteria