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Biomedical subjects

J B McCormick

Publications and source records attributed to J B McCormick.

At least 145 records · Page 8Linked to original sources
PubMed1983

An arenavirus isolated from wild-caught rodents (Pramys species) in the Central African Republic.

We isolated nine arenavirus strains from blood and/or tissues of Praomys sp. rodents wild-caught in derived savannah and forest gallery areas of the Central African Republic (CAR). Convalescent serum from either humans or animals infected by Lassa, Mozambique, or lymphocytic choriomeningitis virus cross-reacted with the strains from the CAR. However, monoclonal antibodies to these three viruses gave a profile against the CAR strains suggesting major antigenic differences between each of them and the CAR virus. These data along with the fact that other African arenaviruses have been recovered from Mastomys natalensis and not Praomys suggest that this virus is significantly different from the others.

Africa, Central↗
PubMed1983

Case-control study of Mastomys natalensis and humans in Lassa virus-infected households in Sierra Leone.

Lassa virus infection and antibodies were studied in households where Lassa fever cases occurred, and compared to those in nearest neighbor houses and "far" houses located across the village from case houses. Seventy-nine percent of all rodents caught in the houses were Mastomys, the natural reservoir of Lassa virus. Rodent infection was not randomly distributed, but rather focal. Thirty-nine percent of the Mastomys in case houses were viremic, compared to 3.7% in control houses. Human antibody prevalence in case houses was 30%, compared to 20% in non-case houses (P less than 0.05, chi-square test, df = 2). Neither seroconversions nor antibody prevalence rates were associated with household size or number of persons per room. Trapping of rodents in half of the case and control houses resulted in a Mastomys reduction ranging from 2.2- to 3.3-fold. This reduction failed to significantly reduce the seroconversion rate to Lassa virus in the people of trapped houses compared to those in untrapped ones. More complete trapping will be needed in order to better evaluate this procedure as a means of interruption of Lassa virus transmission in endemic villages.

Animals↗
PubMed1983

Ebola virus disease in southern Sudan: hospital dissemination and intrafamilial spread.

Between 31 July and 6 October 1979, 34 cases of Ebola virus disease (22 of which were fatal) occurred among five families in a rural district of southern Sudan; the disease was introduced into four of the families from a local hospital. Chains of secondary spread within the family units, accounting for 29 cases resulted from direct physical contact with an infected person. Among all persons with such contact in the family setting, those who provided nursing care had a 5.1-fold increased risk of infection, emphasizing the importance of intimate contact in the spread of this disease. The absence of illness among persons who were exposed to cases in confined spaces, but without physical contact, confirmed previous impressions that there is no risk of airborne transmission. While the ecology of Ebola virus is unknown, the presence of anti-Ebola antibodies in the sera of 18% of persons who were unassociated with the outbreak suggests that the region is an endemic focus of Ebola virus activity.

Adolescent↗
PubMed1982

Morphological identification of the agent of Korean haemorrhagic fever (Hantaan virus)as a member of the Bunyaviridae.

Korean haemorrhagic fever (KHF) (Hantaan virus), a rodent-borne viral illness, is an important cause of human disease throughout much of Asia and Eastern Europe. The agent responsible for KHF has not yet been conclusively identified. Plaque-purified KHF virus was concentrated and then banded in a potassium tartrate gradient. Material from the 1.17-1.19 g/ml band was examined by electron microscopy and particles with a morphology identical to that of the family Bunyaviridae were found. The particles were aggregated by KHF serum but not by saline solution or non-immune serum. Identification of KHF virus as a member of the family Bunyaviridae implies a potential for spread by arthropod vectors.

Bunyaviridae↗
PubMed1982

Experimental infection of rhesus monkeys with Lassa virus and a closely related arenavirus, Mozambique virus.

As a model for the pathogenesis of Lassa fever in humans, nine rhesus monkeys were inoculated with Lassa virus. Three monkeys had had a previous asymptomatic experimental infection with Mozambique virus, a closely related arenavirus; these monkeys were protected from illness and viremia and manifested only mild pathologic lesions. The other animals developed severe disease and viremia. At necropsy, hepatocellular necrosis, interstitial pneumonia, a unique pulmonary arteritis, adrenal gland necrosis, encephalitis, and uveitis were prominent pathologic lesions which correlated with the organ titers of virus. One animal infected with Lassa virus developed prolonged viremia, a typical immune response, and sudden onset of lower limb paralysis after recovery; at necropsy chronic proliferative arteritis of the spinal cord, brain, and heart was evident. Similarities and differences in the pathologic lesions in this model and Lassa fever in humans indicate that care must be taken in interpreting the results of experiments concerning immune prophylaxis, pathogenesis, and treatment in rhesus monkeys.

Animals↗
PubMed1982

Antibody to Ebola virus in guinea pigs: Tandala, Zaire.

A case-control study was conducted to investigate the findings of antibody to Ebola virus in the serum of a guinea pig from Tandala, Zaire. Case households, defined by the possession of one or more guinea pigs, were compared to neighboring households without guinea pigs. Seven (5.1%) of 138 samples of human sera and 36 (26%) of 138 samples of guinea pig sera had antibody to Ebola virus. There was no clustering of seropositivity among humans or guinea pigs within households, nor was there any association between the ownership of guinea pigs and seropositivity among household members. These data suggest sporadic subclinical infection of guinea pigs and humans without a dominant role for person-to-person or guinea pig-to-guinea pig transmission.

Animals↗
PubMed1982

Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation.

Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with Co60 gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of CO60 radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose per rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. We found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents.

Arenaviridae↗
PubMed1982

Pathologic and virologic study of fatal Lassa fever in man.

Postmortem examination of 21 virologically documented cases of Lassa fever, including 6 complete autopsies, was performed as part of a field study of community-acquired Lassa fever in Sierra Leone. The most consistently observed lesions were hepatocellular, adrenal, and splenic necrosis and adrenal cytoplasmic inclusions. Neither these lesions, nor other milder and less constantly observed lesions such as myocarditis, renal tubular injury, and interstitial pneumonia, appeared severe enough to explain the cause of death in Lassa fever. The central nervous system (CNS) contained no specific lesions. Viral titrations demonstrated high viral content in liver, lung, spleen, kidney, heart, placenta, and mammary gland. Clinical laboratory data included elevation of hepatic enzymes, creatine phosphokinase (CPK), and blood urea nitrogen (BUN). Because of the paucity of pathologic lesions in spite of widely disseminated viral infection, further investigation of humoral inflammatory mechanisms is indicated.

Adult↗
PubMed1980

Antibody response to serogroup A and C meningococcal polysaccharide vaccines in infants born of mothers vaccinated during pregnancy.

During the large epidemic of serogroups A and C meningococcal disease in Brazil, we studied the immunologic response to meningococcal polysaccharide vaccine in infants born to women vaccinated during pregnancy. Radioimmunoassay serum levels against serogroups A and C polysaccharide were more than threefold higher in vaccinated than in unvaccinated women at delivery. Cord blood levels were also threefold or higher in infants whose mothers were vaccinated while pregnant compared to infants born of unvaccinated mothers. Within 3 mo, the infants' A and C serum antibody levels declined by approximately 80%. When vaccinated at about 6 mo of age, infants born of vaccinated mothers had antibody responses to A and C polysaccharide vaccines indistinguishable from those born of unvaccinated mothers. The response did not vary with the trimester of vaccination. We conclude that the vaccination of pregnant women with groups A and C meningococcal polysaccharide vaccine does not produce immune tolerance in the subsequently born infants.

Antibodies, Bacterial↗
PubMed1980

Clinical observations in 42 patients with Lassa fever.

Under continuous observation of several months, 42 patients from the eastern province of Sierra Leone, Liberia (Lofa County), and neighbouring Guinea were identified as Lassa fever cases by indirect immunofluorescent antibody technique, indicating that the disease is endemic in these areas. The clinical course varied from mild disease to severe illness with haemorrhagic disorders. The fatality rate was 14%. The occurrence of only two possible secondary cases suggests that person-to-person spread of the disease is unimportant epidemiologically. There was a wide range of patients' ages, tribes, and occupations, including a 2 months old baby and a white US citizen. Clinical, laboratory, and histopathological investigations demonstrated the panorganotropism of Lassa virus. Haematological tests in few selected haemorrhagic cases with Lassa fever did not support coagulation disorders or thrombocytopenia as causing the bleeding tendency. The histopathologic changes bear resemblance to those observed in Argentinian and Bolivian haemorrhagic fever, both being caused by viruses of the Arena group. However, Lassa virus hepatitis may be differentiated from liver lesions occurring in yellow fever, Marburg virus disease, and Ebola (Maridi) haemorrhagic fever.

Adolescent↗
PubMed1978

Disease control programs in the United States. Control of streptococcal and poststreptococcal disease.

Programs administered by health departments and heart associations for control of streptococcal and poststreptococcal disease differ greatly from state to state. The year 1974 was used as a representative year when studying the variety of state policies and programs regarding surveillance of streptococcal disease, primary and secondary prevention of rheumatic fever, and prevention of poststreptococcal glomerulonephritis. A uniform national policy for streptococcal control is desirable but should be based on evidence not now available concerning the impact of various elements of control programs on morbidity and mortality.

Carrier State↗
PubMed1977

Measles vaccine efficacy determined from secondary attack rates during a severe epidemic.

In February, March, and April 1974, a severe epidemic of measles, with 71 cases and three deaths, occurred on the Cheyenne and Standing Rock Sioux Indian Reservations in South and North Dakota. The attack rate was 9.0 cases per 1,000 persons, and associated with the illness were 24 cases of pneumonia and ten cases of otitis media. Age-specific attack rates were highest in those under one year of age. Using secondary attack rates in persons under nine years of age who were vaccinated and unvaccinated family contacts of cases, vaccine efficacy was measured as 97.3% (95% confidence interval 80.1 to 99.9%).

Adolescent↗
PubMed1977

Wound infection by an indigenous Pseudomonas pseudomallei-like organism isolated from the soil: case report and epidemiologic study.

A 27-year-old farmer in the Oklahoma panhandle was pinned under his overturned tractor for 2 hr and received superficial and deep lacerations. He contracted an infection of a pelvic wound with an organism that had cultural and biochemical characteristics identical to those of Pseudomonas pseudomallei. Identical organisms were recovered from soil taken from the site of the accident. The organism isolated from the wound proved to be less virulent in guinea pigs than usual laboratory strains of P. pseudomallei; fatty acid analysis showed a distinctly different pattern from that of laboratory strains of P. pseudomallei. The infecting organism may be a variant of P. pseudomallei or a new species of Pseudomonas.

Adult↗