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Biomedical subjects

B Duval

Publications and source records attributed to B Duval.

At least 37 records · Page 2Linked to original sources
PubMed1995

Measles, mumps, and rubella antibodies in children 5-6 years after immunization: effect of vaccine type and age at vaccination.

The levels of antibody against measles, mumps, and rubella were determined at 5-6 years postimmunization in 468 children vaccinated with two different trivalent vaccines. The proportions of children without detectable antibody levels were 12 and 3.6% for measles (p < 0.001), 14.9 and 7% for mumps (p = 0.006), and 3.3 and 3.1% for rubella (p = 0.88), respectively, in MMR II and Trivirix recipients. A higher proportion of those vaccinated at younger ages had undetectable or low levels of measles antibody. These data indicate that a large proportion of children vaccinated under routine conditions do not have detectable measles and mumps antibody.

Age Factors↗
PubMed1995

Field effectiveness of erythromycin prophylaxis to prevent pertussis within families.

To evaluate the field effectiveness of erythromycin prophylaxis for pertussis within families, a retrospective cohort study was conducted among 246 families. Overall 41% of the subjects (387 of 940) had been sick. The secondary attack rate was 65% for infants younger than 2 years, 54% for those 2 to 4 years old and 39% for children 5 to 9 years old, and it declined thereafter. The secondary attack rate decreased from 25% in families without prophylaxis to 17% in families with prophylaxis. The protection induced by prophylaxis did not vary with age or vaccination status. When prophylaxis was used before the onset of a secondary case, the secondary attack rate was 4% compared with 35% when given after a secondary case (P < 0.001). Erythromycin prophylaxis seems to be efficient in preventing secondary cases but is most useful when administered before the occurrence of the first secondary case.

Adolescent↗
PubMed1995

Seroepidemiologic study of three zoonoses (leptospirosis, Q fever, and tularemia) among trappers in Québec, Canada.

This study was undertaken to evaluate the prevalence of antibodies against Francisella tularensis, Coxiella burnetii, and certain serovars of Leptospira interrogans among trappers in Québec, Canada. Muskrat trapping was identified as a risk factor for F. tularensis infection, whereas having a cat at home apparently protected trappers against infection by L. interrogans. High percentages of control sera were positive for antibodies against C. burnetii (15%) and L. interrogans (5%), most frequently serovar bratislava. This is the first report of human infection by serovar bratislava in North America.

Adult↗
PubMed1995

Need for vaccination of sewer workers against leptospirosis and hepatitis A.

OBJECTIVES: This study compared the prevalence of Leptospira interrogans and hepatitis A virus (HAV) antibodies in serum samples from sewer workers and controls. METHODS: A blood sample was obtained from 76 of the 101 municipal sewer workers (75%) of Quebec City and from two controls matched to each for age and sex. Testing was done for antibodies against serovars of Leptospira icterohaemorragiae, bratislava, hardjo, grippotyphosa, and kennewicki (pomona) and hepatitis A. RESULTS: Sewer workers had a greater prevalence of antibodies against leptospirosis than controls (12% v 2%, P = 0.003). In contrast, antibodies to HAV were not significantly more prevalent among workers than among controls (54% v 49%, P = 0.51). Prevalence of HAV antibodies increased significantly with age both among workers and controls (chi 2 for trend, P < 0.001). In contrast with younger workers, prevalence of HAV antibodies was greater among workers > or = 40 years than among their controls (81% v 65%, P = 0.04). CONCLUSION: Leptospirosis continues to be a problem to sewer workers but hepatitis A is apparently no longer a risk. The likely explanation is that leptospira are still abundant in the sewage system in contrast with HAV, which is only rarely to be found in sewage as a result of the generalised decrease in incidence of hepatitis A in the past three decades. The decision to vaccinate sewer workers against hepatitis A should take into account that it is impossible to avoid all contact with sewage fluid and, despite the fact that the actual incidence of hepatitis A is low, there is a real possibility of sporadic exposure during a future outbreak.

Adult↗
PubMed1995

The microbial community of Ophrydium versatile colonies: endosymbionts, residents, and tenants.

Ophrydium versatile is a sessile peritrichous ciliate (Kingdom Protoctista, class Oligohymenophora, order Peritrichida, suborder Sessilina) that forms green, gelatinous colonies. Chlorophyll a and b impart a green color to Ophrydium masses due to 400-500 Chlorella-like endosymbionts in each peritrich. Ophrydium colonies, collected from two bog wetlands (Hawley and Leverett, Massachusetts) were analyzed for their gel inhabitants. Other protists include ciliates, mastigotes, euglenids, chlorophytes, and heliozoa. Routine constituents include from 50-100,000 Nitzschia per ml of gel and at least four other diatom genera (Navicula, Pinnularia, Gyrosigma, Cymbella) that may participate in synthesis of the gel matrix. Among the prokaryotes are filamentous and coccoid cyanobacteria, large rod-shaped bacteria, at least three types of spirochetes and one unidentified Saprospira-like organism. Endosymbiotic methanogenic bacteria, observed using fluorescence microscopy, were present in unidentified hypotrichous ciliates. Animals found inside the gel include rotifers, nematodes, and occasional copepods. The latter were observed in the water reservoir of larger Ophrydium masses. From 30-46% of incident visible radiation could be attenuated by Ophrydium green jelly masses in laboratory observations. Protargol staining was used to visualize the elongate macronuclei and small micronucleus of O. versatile zooids and symbiotic algal nuclei. Electron microscopic analysis of the wall of the Chlorella-like symbiont suggests that although the Ophrydium zooids from British Columbia harbor Chlorella vulgaris, those from Hawley Bog contain Graesiella sp. The growth habit in the photic zone and loose level of individuation of macroscopic Ophrydium masses are interpretable as extant analogs of certain Ediacaran biota: colonial protists in the Vendian fossil record.

Animals↗
PubMed1993

Frequency of sexually transmitted diseases among university students.

OBJECTIVE: To estimate the incidence rate of sexually transmitted diseases (STDs) among university students and evaluate the associated sociodemographic factors. DESIGN: Mail survey in April 1990. Included in the questionnaire were questions about the subjects' STD experience since their admission to the university and the type and date of the infection. SUBJECTS: Of the 19,682 undergraduate students 2920 subjects, in 10 groups of 292, were randomly selected. A total of 1731 (59.4%) completed the questionnaire. MAIN OUTCOME MEASURES: Estimated annualized incidence rates of genital human papillomavirus infection and Chlamydia infection. RESULTS: The estimated annualized incidence rates of genital human papillomavirus and Chlamydia infections were 2.2% and 1.5% respectively. Among the students who indicated being infected with genital human papillomavirus 59% were 18 to 21 years old (p < 0.05), 76% were women (p < 0.01) and 69% had more than one sexual partner (p < 0.01). No statistically significant associations were observed between age, sex and Chlamydia infection. On the other hand, 95% of the cases of Chlamydia infection were found among those who had more than one sexual partner (p < 0.01). CONCLUSION: University students continue to have sexual activities at risk for STDs and should be specifically targetted by general practitioners and health services in an effort to slow the spread of STDs.

Adolescent↗
PubMed1993

[Factors associated with at-risk anal relations in homosexual HIV-seropositive men].

This pilot study proposes an index to quantify the intensity of high-risk anal sex and presents factors associated with this practice among 65 homosexual men with HIV infection. All of them answered a self-administered questionnaire. Using multiple logistic regression, we first compared those who had had safe sex in the past six months to those who had had unsafe sex. Variables significantly associated with unsafe sex are: drugs and/or alcohol use with sex, and less favorable attitude towards condom use. Finally, multiple linear regression analysis among respondents who had had unsafe sex indicated that the following factors are associated with higher levels of unsafe sex: men between the ages of 32 and 38, satisfied with their social life, non-smokers, with a less favorable attitude towards condom use, and with few social relationships. These results must be interpreted with caution because of the small number of respondents.

Attitude↗
PubMed1992

Understanding physicians' decision to perform a clinical examination on an HIV seropositive patient.

The main purpose of this study was to identify the psychosocial factors explaining a physician's decision to perform a clinical (physical) examination of an HIV seropositive patient. Eight hundred seventy-nine physicians completed a questionnaire investigating psychosocial variables derived from the theories of Ajzen and Triandis. The mean intention to perform a clinical examination was quite positive (5.4 on a 7-point scale). The regression of intention on all variables yielded an adjusted R2 of .499. Among few significant predictors, by far the most important was the perceived norm among fellow physicians regarding performance of the clinical examination. It is concluded that educational interventions aimed at the physician population should focus on the social role and personal efficacy of physicians regarding this type of clinical examination rather than giving information concerning the low risk of contracting the HIV.

Attitude of Health Personnel↗
PubMedDate not supplied

[Lack of conviction about vaccination in certain Quebec vaccinators].

A questionnaire was mailed to all vaccinators in Quebec in 1998. The objective of this survey was to document vaccinators' attitudes, knowledge, and practices related to vaccination. Vaccinators generally believe in the security, efficacy and usefulness of vaccines given to young children. However, 41% of nurses do not fully agree with these opinions. More than 94% of pediatricians completely disagree that "certain practices (homeopathy, good eating habits and a healthy lifestyle) can eliminate the need for vaccination", compared with 85% of general practitioners and only 60% of nurses. Less than 25% of doctors recall children who are late in getting their immunizations; approximately 45% of vaccinators are in complete agreement with simultaneous injections of two vaccines; many circumstances are incorrectly seen as contra indications for vaccination. Public health authorities should target systematic interventions towards vaccinators to improve this situation and to increase nurses' conviction regarding the benefits of vaccination.

Adult↗
PubMedDate not supplied

University students' intention to seek medical care promptly if symptoms of sexually transmitted diseases were suspected.

The aim of this study was to identify the factors explaining intention to seek medical care promptly if STD symptoms were suspected. A random sample of 1617 undergraduate students completed a questionnaire assessing intention, attitude, perceived norm among friends, perceived behavioral control, and risk of disease, along with different socio-demographic variables. The regression of intention on all variables yielded an adjusted R2 of 0.32 (P < 0.0001). The factors explaining this variance were the perceived advantages, easiness, and social norm among friends regarding seeking medical care promptly, age, and gender. Perception of risk to delay seeking medical care and perceived personal risk of getting STDs were not significant variables. Overall, the results indicate the need to develop programs for male first-year students. These programs will have to influence the attitude, that is, the perceived advantages of seeking medical care promptly if STD symptoms are suspected. Seeking advice from students' friends, and perception of these friends as a significant reference source if STD symptoms are suspected, should also be promoted.

Adolescent↗
PubMedDate not supplied

[Impact of active research for vaccination information in children with incomplete or lost vaccination records].

UNLABELLED: We estimated the accuracy of the information in the vaccination booklet of 8,457 children. The booklets were classified as complete (CC), incomplete (CI) or lost (CP). For children in the CI or CP categories, an active search was done in their providers' records and we assessed their vaccine coverage. Overall, the booklet provided accurate information for 88.6% of the 7,646 children who were vaccinated at least once. Among the 711 children in the CI category, the active search showed that 79% had received all their vaccines at age two years whereas this proportion was 59% among the 280 children in the CP category. The active search increased the vaccine coverage in the population by 4%. CONCLUSION: The majority of children in the CI or CP categories whose parents report that they received all their vaccines are in fact adequately vaccinated.

Child Welfare↗
PubMedDate not supplied

[Major measles epidemic in the region of Quebec despite a 99% vaccine coverage].

The 1989 measles outbreak in the province of Quebec has been largely attributed to an incomplete vaccination coverage. In the Quebec City area (pop. 600,000) 1,363 confirmed cases of measles did occur. A case-control study conducted to evaluate risk factors for measles allowed us to estimate vaccination coverage. It was measured in classes where cases did occur during the outbreak. This population included 8,931 students aged 5 to 19 years old. The 563 cases and a random sample of two controls per case selected in the case's class were kept for analysis. The vaccination coverage among cases was at least 84.5%. Vaccination coverage for the total population was 99.0%. Incomplete vaccination coverage is not a valid explanation for the Quebec City measles outbreak.

Adolescent↗
PubMedDate not supplied

[Selection of target behaviors before planning health education objectives: application to prevention of STD in teenagers].

This article describes a semi-quantitative technique enabling the person responsible for the planning of a health education program to select the behaviour that should be targeted. The technique is adapted from Morley and used within Green's health education planning model. The relevant behaviours are ranked according to their importance and their changeability. A global weight is calculated for both by multiplying the weights attributed for each criterion of importance and changeability. This method is illustrated by an application for sexually transmitted diseases in teenagers. Calculations are made both for younger and older teenagers.

Adolescent↗
PubMedDate not supplied

[The opinions of Quebec physicians regarding AIDS: Part II].

Based on a representative sample of Quebec physicians (n = 879), this study assesses physicians' motivation to perform a clinical examination on an HIV-infected patient and their opinion about issues related to HIV screening. Confronted with an HIV-infected patient, 70% of physicians would perform a clinical examination; however, more senior medical specialists with fewer contacts with patients seem less inclined to perform a clinical examination on these patients. Almost 80% agree with a mandatory nominal confidential notification of positive HIV screenees. However, 33% agree with the practice of contact tracing and 40% consider it acceptable to test a patient without his or her explicit consent. Even if Canada does not regulate the testing of immigrants for HIV, more than 75% of the respondents agree with such a policy. Finally, a negative association was observed between the intent to perform a clinical examination on an HIV-infected patient and a favourable attitude toward the screening of immigrants and the testing of patients without their consent.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

[The opinion of Quebecois physicians with regard to AIDS].

A mail survey on several medical and social issues surrounding the AIDS epidemic was conducted among Québec physicians of a random sample. Of 1,530 physicians, 879 (57.5%) returned their completed questionnaire. Results show that the majority of physicians (79.3%) considered AIDS as a priority. A large proportion of physicians (66%) overestimate the occupational risk of contracting HIV following exposure to a contaminated needle. Logistic regression suggests that the perceived risk of contracting HIV through contact with patients is directly related to the physicians' type of medical training and to their estimate of the risk of contamination with a contaminated needle. Finally, a third of the respondents consider continuing medical education on AIDS insufficient in the Province of Québec while 82.1% want to improve their knowledge about AIDS.

Acquired Immunodeficiency Syndrome↗