Anti-HIV antibodies and other serological and immunological parameters among normal Haitians in Montreal.

A matched-pair, cross-sectional study of lymphocyte and serological parameters associated with acquired immune deficiency syndrome (AIDS) in 189 randomly chosen, ostensibly healthy adult Haitian immigrants residing in Montreal matched for sex, age (within 5 years), and neighborhood of residence to 189 non-Haitian (Caucasian) controls was done in 1983-1984. Three years later (1986-1987), 41 of the Haitian study subjects and 83 of the non-Haitian controls participated in a follow-up study centered on lymphocyte parameters. A significantly greater number of Haitians than controls had produced antibodies to Toxoplasma gondii. In addition, a greater percentage of the Haitians than the controls were also producing antibodies to two other opportunistic pathogens frequently encountered in AIDS, cytomegalovirus and hepatitis B virus, implying that the Haitians in general had had greater exposure to a variety of infectious agents than had the controls. A few study participants were producing antibodies against two viruses that are related to the human immunodeficiency virus-type 1 (HIV-1), the human T-cell lymphotropic viruses I and II (HTLV-I and -II). Two Haitians and one control were producing antibodies against HTLV-I. One study subject and four controls were HTLV-II seropositive. The most interesting and surprising finding was that four (2.1%) of the Haitian study subjects but none of the controls were seropositive for HIV-1. These individuals, two of whom were women and two men, were asymptomatic. Although their individual lymphocyte parameter values fell in the normal range, as a group they had statistically significantly lower average values for their lymphocyte parameters than did the HIV-seronegative Haitian study objects.(ABSTRACT TRUNCATED AT 250 WORDS)

Sensitivity to "atypical" mycobacteria in high school children in two community health departments.

To evaluate the prevalence of atypical mycobacteria infections in our population, a study was done among students of secondary fifth grade (15-19 years of age) in the community health departments of Maisonneuve-Rosemont in Montreal and of Sherbrooke. The tuberculin used was the RT-23 2 T.U. with Tween 80 and the sensitins prepared by the Statens Serum Institute of Copenhagen from Mycobacterium intracellulare (Battey) and from Mycobacterium kansasii. Each student had a tuberculin test on one arm and a sensitin test on the other. The sensitins were randomly allocated. Depending on how the prevalence is calculated, the Mycobacterium intracellulare infection varies from 3 to 20% in Montreal and from 0 to 9.6% in Sherbrooke. The Mycobacterium kansasii infection is much less important in both regions. All reactions to those atypical mycobacteria are in the range of tuberculin reactions of 0 to 9 mm. In our population which is weakly infected with atypical mycobacteria, the level of positivity of tuberculin reactions to 2 T.U. RT-23 or 5 T.U. P.P.D. would give a more realistic evaluation of M. tuberculosis infection if it was fixed at 5 mm than at 10 mm as it is now.

BCG vaccination and pulmonary tuberculosis in Quebec.

The BCG vaccination program officially set up in 1949 in the Province of Quebec has been retrospectively evaluated for the period from 1956 to 1961. Two series of age groups were studied, 0-14 and 15-29, each comprising populations of several hundred thousand. At the beginning and the end of the period, the rates of primary vaccination were, in percentages of viable births, from 40 to 47.8 and, in cumulative percentages, for the 0 to 14 year age group, from 39.98 to 53.41, and for the 0 to 29 year age group, from 29.22 to 45.98.During this period, the ratios between the yearly rates of incidence of new cases of pulmonary tuberculosis per 100,000 in vaccinated and non-vaccinated individuals ranged from 1-2.5 to 1-3.5 within the age group 0-14 years and from 1-4.5 to 1-7 within the age group 15-29 years. When only the incidence of the more severe forms of tuberculosis is considered, the ratios ranged from 1-3.7 to 1-6.0 for the younger group and from 1-5.3 to 1-7.6 for the older one.Mortality from pulmonary tuberculosis was practically non-existent in the vaccinated groups and decreased from 2.5 to 1.3 per 100,000 population in the non-vaccinated groups.

Trials of aqueous killed influenza vaccine in Canada, 1968-69.

The appearance of the pandemic A/Hong Kong/1/68 (H3N2) influenzavirus strain provided an opportunity for a clinical field trial of influenza vaccines in Canada during the winter of 1968-69. As by November 1968 there were reports of influenza B activity and as supplies of A2/HK/68 vaccines were limited, it was decided to make a series of strictly randomized double-blind trials comparing A2/HK/68 vaccines not only with B/Mass/66 vaccines but also with a bivalent vaccine that was already in production and contained B/Mass/66 and A2/Mtl/68, the latter a strain isolated in Canada during January 1968. In 4 trials, a total of 13 729 military personnel and 4 795 primary schoolchildren were vaccinated. Reported vaccine reactions were less than 0.1% with zonally-purified vaccines and 2.6% with the "standard" aqueous killed bivalent vaccine. Three children had serious reactions. Surveillance detected an outbreak of influenza in the first two trials on the military. The 3 vaccines containing A2 strains gave similar clinical protection conservatively estimated at 42-55% but probably about 80%. The effectiveness of the A2/Mtl/68 vaccine, which was in production before the Hong Kong variant had been isolated, was unexpected. In the absence of a vaccine specific to a new pandemic strain, it should not be assumed that a vaccine made from another recent strain could not be useful.

Immunologic findings in healthy Haitians in Montreal.

To investigate the occurrence of acquired immune deficiency syndrome in Haitians, a health status questionnaire was administered and selected studies of immune status done in a randomly chosen sample of 189 healthy adult Haitians living in Montreal. The study group was comparable to a large sample of Haitians in Montreal interviewed in the 1981 census with respect to age, sex, number of persons per household and year of immigration, but the proportion of currently married people in the study was larger (60.8% v. 42.6%). The results in the study group were compared with those in a sample of 189 non-Haitians matched for age, sex and neighbourhood of residence. Persons with known causes of impaired immune function were excluded. The participation rate was 87.5%. The study and control groups both reported few symptoms and chronic health problems and had comparable demographic data, including rate of employment and income. The mean total numbers of lymphocytes, OKT3 and OKT4 (helper) and OKT8 (suppressor) cells were significantly higher in the Haitians than in the controls, though still within normal limits. There was a borderline elevation of the lymphocyte response to phytohemagglutinin in the Haitians. The ratios of helper to suppressor T cells in the two groups were, however, not significantly different. The Haitians, in comparison with non-Haitians living in the same community, had no demonstrable abnormalities of cellular immune function.

Effect of screening and treatment on imported intestinal parasite infections: results from a randomized, controlled trial.

A randomized, controlled trial was undertaken to evaluate the effects of a screening program for intestinal parasite infection in newly arrived Southeast Asian refugees to Montréal, Québec, Canada, during 1982-1983. Families assigned to the screened groups were examined, infected persons were treated and followed until they were infection-free, and all screened families were reexamined at six months. Families assigned to the control groups were examined at six months only. Statistically significant prevalence differences in unadjusted and adjusted estimates over the six-month study period were found between screened persons and controls for each of three groups of refugees from Kampuchea, Laos, and Vietnam, respectively. In general, the greatest prevalence differences ascribed to the screening program were observed in hookworm and Ascaris lumbricoides infections. Continued high levels of Giardia lamblia and Strongyloides stercoralis infection were observed at six months; this raises concerns over the effective therapeutic management of infected persons, the risk of local transmission, and the relevance of screening for intestinal parasites in new arrivals from endemic areas.