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Biomedical subjects

W Stackiw

Publications and source records attributed to W Stackiw.

At least 19 recordsLinked to original sources

Increased risk of early measles in infants of human immunodeficiency virus type 1-seropositive mothers.

An increase in illness due to measles is one of the potential consequences of the human immunodeficiency virus (HIV) epidemic in Africa. During a study of perinatal HIV transmission conducted in Kenya, the risk of acquiring measles before vaccination (9 months of age) was found to be 3.8 times higher in infants born to HIV-seropositive mothers than in control infants (10 [9%] of 109 vs. 5 [3%] of 194 infants; P = .02; odds ratio, 3.8; 95% confidence interval, 1.2-13.2). The majority of infants who developed measles in this study had significant sequelae related to their measles infection. The increased risk of measles appeared to be related to relatively lower anti-measles antibody titers detected in cord blood samples of affected infants born to HIV-seropositive mothers. However, 94% of all infants were susceptible to measles on the basis of ELISA testing at age 6 months regardless of maternal HIV serology. These observations highlight the need for improved measles vaccination strategies in Africa and for studies to delineate the effects of HIV infection on the incidence, presentation, and sequelae of childhood infectious illnesses.

Antibodies, Viral

Manitoba virus, a new rhabdovirus isolated from Culex tarsalis mosquitoes collected in Manitoba, Canada.

A rhabdovirus, Mn 936-77, was isolated from a pool of two Culex tarsalis collected on August 16, 1977, from Morris, Manitoba. Isolate Mn 936-77 was not pathogenic for suckling Swiss white mice inoculated by the intracerebral route. The virus propagated in three vertebrate cell lines (Vero, primary chick embryo, mouse neuroblastoma), but apparently not in Aedes albopictus C6/36 cells. Isolate Mn 936-77 did not react by amplified enzyme-linked immunosorbant assay with 230 viruses of proven or possible arbovirus etiology or by immunofluorescence with 88 members of the family Rhabdoviridae. Isolate Mn 936-77 appears to be a newly discovered virus for which the name Manitoba virus is proposed.

Animals

Impact of human immunodeficiency virus type 1 on tuberculosis in rural Haiti.

We conducted a case-control study to determine the relative and attributable risk of HIV seropositivity for bacillary-positive (smear and/or culture) pulmonary tuberculosis in Haiti. There were 274 patients with tuberculosis and an equal number of control subjects. Antibodies to HIV were present in 67 (24%) patients and eight (3%) control subjects. Odds ratios suggested that the risk of pulmonary tuberculosis was 15.7 times as great (95% confidence interval, 4.8 to 5.0; p less than 0.05) in patients 20 to 39 yr of age who were HIV-seropositive than in HIV-seronegative patients. In contrast, the relative risk in those 40 to 59 yr of age was elevated (3.0 times), though not significantly (lower 95% confidence interval, 0.8). In the 20- to 39-yr age group, 31% of tuberculosis was attributable to HIV infection (95% confidence interval between 23 and 39%). HIV-seropositive and HIV-seronegative patients did not differ with respect to sputum smear positivity. HIV-seronegative patients were twice as likely to be infected with resistant organisms, though this was not significant. We conclude that HIV infection is a major risk factor for pulmonary tuberculosis in young adult residents of Haiti. This, together with the fact that similar proportions of HIV-seropositive and HIV-seronegative patients were potentially infectious, suggests that without vigorous counteraction tuberculosis will become a greater problem for Haiti.

Acquired Immunodeficiency Syndrome

Foodborne gastroenteritis due to Norwalk virus in a Winnipeg hotel.

Within 1 week four separate incidents of gastroenteritis presumed to be foodborne were reported by guests of a Winnipeg hotel. Investigation revealed poor food-handling practices and illness among the kitchen staff. Elevated bacterial counts and Escherichia coli were found in 15 of 24 samples of food tested, and Staphylococcus aureus was isolated from 2 pastry samples. Culture of 14 stool samples for bacteria yielded Clostridium perfringens in 1 sample from a staff member and coagulase-positive S. aureus in 2 samples from staff members and 3 from guests. All of the S. aureus isolates were nonenterotoxigenic and had three different phage patterns. Electron microscopy and immunoelectron microscopy revealed the prototype Norwalk virus in five (56%) of nine stool samples; four samples were from guests, and one was from a kitchen employee. The employee had had diarrhea 24 hours before the first outbreak and was thus believed to be the source of the virus infection, possibly through food handling. This is the first report of Norwalk virus isolation and the first of foodborne Norwalk virus transmission in Canada. A review of foodborne Norwalk virus infections is presented.

Acute Disease

Antibody to hepatitis D virus (delta agent) in selected Manitoba residents, 1974-1986.

The prevalence of antibody to Hepatitis D Virus (HDV) was determined in serum samples collected from 174 Manitoba residents between 1974 and 1986. Anti-delta was detected in five of 123 HBV-infected individuals for an overall prevalence of 4.1%. Three of 54 (5.5%) persons who were sampled in the period 1974-77 were anti-delta positive, as were two of 69 (2.9%) sampled between 1982 and 1986 (p greater than 0.05). Four of 31 (12.9%) acute hepatitis B patients, and one of 92 (1.1%) chronic HBsAg carriers were anti-delta positive. Three of four intravenous drug abusers were anti-delta positive, as compared to two of 69 who denied drug abuse (p less than 0.0005). In three of the four patients with acute delta hepatitis, anti-delta was detectable in convalescent serum only; all four patients made a complete clinical recovery. A possible false-positive reaction for anti-delta was observed in the serum of one of 51 HBsAg negative controls, a patient with acute hepatitis A who was negative for all hepatitis B markers. These results indicate that HDV has been present in Manitoba since at least 1974, though at a relatively low level, and that infection is strongly associated with intravenous drug abuse. Reliable detection of anti-delta in patients with acute delta hepatitis requires the testing of serial serum specimens.

Carrier State

An evaluation of measles serodiagnosis during an outbreak in a vaccinated community.

During an epidemic of measles in a vaccinated community, five serodiagnostic tests were performed on 67 persons on whom clinical and epidemiological data were available. The test found most suitable for a rapid diagnosis of measles infection was an Enzyme Linked Immuno Sorbent Assay for the detection of specific IgM antibodies. Only one false negative IgM was recorded. In a group of 45 persons who fulfilled the clinical definition of measles, specific IgM antibodies were detected in the acute phase serum of only 30 (66.6%), of whom 17 were vaccinated. When the convalescent sera were tested, specific IgM antibodies were detected in 25 of the 28 (89.2%) vaccinated, and in 17 of the 17 (100%) non vaccinated clinical cases. A convalescent blood should be tested in persons with a rash illness and no IgM antibodies in the acute phase serum. There were individual variations in the time of appearance of IgM. On the day of onset of rash, IgM antibodies were detected in 7 of the 12 (58.3%). A history of prior vaccination is not always associated with immunity nor with the presence of specific antibodies.

Adolescent

Adenovirus infections in Manitoba.

This review of adenovirus infections in Manitoba over a five-year period is introduced with a brief presentation on the structure-function relationships of the adenoviruses. Extensive research has resulted in the accumulation of a great deal of basic information, far surpassing our knowledge about the infections that these viruses produce in man. More research is needed on the epidemiological and clinical aspects of these diseases, including methods for prevention and treatment, and earlier methods of diagnosis.Features of 216 adenovirus respiratory infections diagnosed from 1963 to 1967 are reviewed and presented. All infections were diagnosed by showing a four-fold or greater increase. In addition, an adenovirus was isolated from many of the infections. These infections occurred every year in substantial numbers and they were seen during each month of the year, although they were more frequent and severe in the winter. Infants and younger persons were often affected. The most severe disease was a pneumonitis which occurred mainly in infants. Associated symptoms usually arose from the gastrointestinal tract, and were sufficiently common to indicate that one should suspect an adenovirus infection when respiratory and gastrointestinal symptoms occur together in a child.The possible role of adenoviruses in the etiology of other than respiratory diseases is discussed and the features of 96 possible non-respiratory infections are presented. Further work will be required to establish a definite etiologic role of the adenoviruses in most of these infections.

Adenoviridae Infections

Surveys of respiratory virus antibodies in an Arctic Indian population.

A study was undertaken to determine the etiological agents responsible for epidemics in a small and relatively isolated Arctic community.Three serological surveys were carried out over a four-year period employing complement fixation tests. Clinical information from the resident nurse was also available.The results indicated that of the two clinical epidemics of "influenza" which occurred during the period of study one was due to influenza virus type A; the other was unidentified. However, influenza virus type B affected approximately 30% of the population at some time during a two-year period without being clinically recognized. An epidemic affecting mainly children, which was clinically considered to be whooping cough, was probably caused by an adenovirus. A mumps epidemic with a high attack rate for all age groups which had occurred a few months prior to the first survey was confirmed. Sendai virus and psittacosis virus are probably endemic in this community.

Adenoviridae Infections