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Biomedical subjects

T W Gyorkos

Publications and source records attributed to T W Gyorkos.

At least 55 records · Page 3Linked to original sources
PubMed1989

Absence of significant differences in intestinal parasite prevalence estimates after examination of either one or two stool specimens.

The authors undertook a retrospective search of intestinal parasite laboratory records obtained from 200 consecutive-day pairs of stool specimens to compare prevalence estimates from the first and second stool examinations. The laboratory results had previously been recorded as part of a screening program offered to Southeast Asian refugees arriving in Montréal, Québec, Canada, between July 1982 and February 1983. No statistically significant differences in either overall prevalences or parasite-specific prevalences were observed. This suggests that, at least in some population-based situations, single stool examinations provide estimates of intestinal parasite prevalence which are as valid as those from the routine examination of two consecutive-day specimens. Blinded studies must be undertaken to accurately assess the true value of multiple specimen submission in epidemiologic studies.

Asia, Southeastern↗
PubMed1988

[Tuberculin reactors among refugee status claimants newly arrived in Canada].

A large number of new cases of tuberculosis are reported among immigrants to Canada every year. For public health purposes immigration policy requires that all immigrants undergo chest radiography and that those found to be infectious receive treatment and follow-up. Since 1984 the clinique Santé-Accueil of the département de Santé communautaire, hôpital Saint-Luc, Montreal, has participated in the screening of immigrants arriving in Quebec who claim refugee status. We undertook a descriptive study to determine the prevalence of tuberculous infection in this population. Of 865 tuberculin tests administered and read, 329 (38%) produced reactions 10 mm or more in diameter. The proportion of positive reactions was higher among older immigrants and varied by country of origin, from 30% for people from El Salvador to 61% for those from Haiti. A history of vaccination with bacille Calmette-Guérin or the presence of a scar was not associated with a positive reaction. Three cases of pulmonary tuberculosis were identified, for a rate of 118/100,000. Our findings underline the importance of systematically screening immigrants for tuberculous infection with the tuberculin test.

Adolescent↗
PubMed1982

The population biology and control of Ascaris lumbricoides in a rural community in Iran.

Adults of Ascaris lumbricoides were recovered from 252 persons in the village of Jazin near Esfahan, Iran after treatment with pyrantel pamoate. This horizontal study provides information on age-specific prevalence rates, intensities of infection, frequency distributions, sex ratios and eggs per gram of stool at different parasite intensities. Recruitment of A. lumbricoides was then monitored at 7, 30, 60, 90 and 365 days after treatment in 110 persons. A separate sample population was examined at monthly intervals and, in addition, the stool of each member of a nine-person family was examined for 10 consecutive days. These data are analysed and used to describe the dynamics of transmissions and recruitment of A. lumbricoides in Jazin. The population dynamics of ascariasis are discussed in the context of R the basic reproductive rate of the parasite. The relationships of R with frequency distributions, prevalencies and worm burdens are discussed. Because of the considerable potential of A. lumbricoides to re-infect man in endemic areas, it is shown that it will be difficult to eradicate ascariasis by the use of chemotherapy, even when drugs with a high efficacy are used repeatedly.

Adolescent↗
PubMed1979

Parasitic disease in humans: the extent in Canada.

Much is being said, often dramatically, about the potential hazards of parasitic diseases in Canada, but little or no attempt has been made to determine the true extent of the problem. Indigenous parasite pathogens are recognized in resident Canadians, and pathogens are acquired by travellers abroad or reported from immigrants. The role of each of these categories is important in the characterization of the problem of parasitic diseases in Canada. From data provided by provincial laboratories and hospitals it is estimated that 1 person in 1000 will spend 1 day per year in hospital because of intestinal parasites, and 1 in 100 each year will have a diagnosis of intestinal parasitic infection made from examination of a stool sample.

Amebiasis↗
PubMed1979

Socio-agricultural factors and parasitic infections in the Caspian littoral region of Iran.

Surveys for intestinal parasites in villages in the Babol area of the Caspian littoral region of Iran have been conducted for five years. During this period, mass chemotherapy and individual treatment have been administered. While the overall prevalence of parasitic disease was reduced after these campaigns, reinfection took place repeatedly, and at a rapid rate. This paper re-examines the prevalence of seven helminth species (Ascaris lumbricoides), hookworms (Ancylostoma duodenale and Necator americanus), Hymenolepis nana, Strongyloides stercoralis, Taenia saginata, Trichostrongylus spp. and Trichuris trichiura) on the basis of geographical and socio-agricultural criteria. The considerable differences in the prevalence of these parasitoses--even between neighboring villages--emphasize the variability of human ecology in the region under study.

Agriculture↗
PubMedDate not supplied

Inferences for likelihood ratios in the absence of a "gold standard".

Likelihood ratios are extensively used to evaluate the performances of diagnostic tests and to update prior odds of disease to posttest odds. Since few tests are truly 100% accurate, including many used as "gold standards," it is important to be able to estimate likelihood ratios in cases where no such standard is available. In this paper, methods to calculate point and interval estimates for likelihood ratios are described. The results numerically coincide with those reviewed by Centor when a "gold standard" is assumed available, but typically provide wider interval estimates when such a standard is not available, reflecting the increased uncertainty inherent in such situations. Unlike previous techniques, the methods do not require normal approximations or logarithmic transformations, and hence provide accurate estimates even when parameter distributions are highly skewed. The methods are illustrated using the results of two different diagnostic tests for the presence of an intestinal parasitic infection.

Algorithms↗
PubMedDate not supplied

Increasing referral of at-risk travelers to travel health clinics: evaluation of a health promotion intervention targeted to travel agents.

BACKGROUND: Increases in travel-related illness require new partnerships to ensure travelers are prepared for health risks abroad. The travel agent is one such partner and efforts to encourage travel agents to refer at-risk travelers to travel health clinics may help in reducing travel-attributable morbidity. METHODS: A health promotion intervention encouraging travel agents to refer at-risk travelers to travel health clinics was evaluated. Information on the knowledge, attitudes, and behaviors of travel agents before and after the intervention was compared using two self-administered questionnaires. The Wilcoxon signed rank test was used to compare the mean difference in overall scores to evaluate the overall impact of the intervention and also subscores for each of the behavioral construct groupings (attitudes, barriers, intent, and subjective norms). Multiple regression techniques were used to evaluate which travel agent characteristics were independently associated with a stronger effect of the intervention. RESULTS: A small improvement in travel agents overall attitudes and beliefs (p =.03) was found, in particular their intention to refer (p =.01). Sixty-five percent of travel agents self-reported an increase in referral behavior; owners or managers of the agency were significantly more likely to do so than other travel agents (OR = 7.25; 95% CI: 1.64 32.06). Older travel agents, those that worked longer hours and those with some past referral experience, had significantly higher post-intervention scores. CONCLUSIONS: Travel agents can be willing partners in referral, and agencies should be encouraged to develop specific referral policies. Future research may be directed toward investigating the role of health education in certification curricula, the effectiveness of different types of health promotion interventions, including Internet-facilitated interventions, and the direct impact that such interventions would have on travelers attending travel health clinics.

Adult↗
PubMedDate not supplied

The hepatitis B immunization strategy in Nova Scotia: is it effective?

Since 1987, both hepatitis B disease and hepatitis B vaccine utilization have increased dramatically in Nova Scotia. We present a review of hepatitis B vaccine utilization relative to the occurrence of disease in Nova Scotia. In the two regions with the highest incidence rates, cases have been increasingly associated with lifestyle-related risk factors. Vaccine utilization was primarily for occupational risks. The current provincial hepatitis B immunization strategy is to recommend immunization to targeted high-risk groups. This strategy was judged to be ineffective. The cost of the vaccine is the most important deterrent for adopting an expanded or universal immunization strategy. The pooling of hepatitis B vaccine orders across Canada is suggested as a means to effect significant reductions in the cost of vaccine. Provincial programs would then be able to expand coverage to include populations at immediate risk and youngsters prior to the start of high-risk activity.

Communicable Disease Control↗
PubMedDate not supplied

Contact-tracing among injection drug users in a rural area.

An epidemic of hepatitis B occurring in 1988 and 1989 in Cape Breton brought to light the existence of a group of "buddies" who engaged in injection drug use. Interviewing was conducted by Public Health in 82% of the 186 IDU contacts named. In comparison with published reports of contact-tracing efforts for viral hepatitis among IDUs, the Cape Breton experience seems successful. This article describes the approach used by Public Health. Aspects of the management of the epidemic and the interview technique which may have contributed to the comparative success of contact-tracing include collaboration with family physicians and laboratories; collaboration among public health investigators; and a nonjudgemental interview technique with 6 "golden rules".

Adult↗
PubMedDate not supplied

Intestinal parasites in refugee claimants: a case study for selective screening?

The medical profiles of 1,967 refugee claimants to Montreal, Quebec, Canada from January 1987 to July 1987 were reviewed to evaluate the importance of imported intestinal parasite infection in this group and to re-examine the screening policy governing these infections. An overall infection rate of 29.3% was obtained for pathogenic parasites, where helminths were four times more frequently found than the protozoa Entamoeba histolytica and Giardia lamblia. Age, sex, years of schooling, country of origin and level of eosinophilia were found to be associated with infection, with country of origin being the strongest predictor of infection. These results document the parasite infection in a select group of immigrants which would not have been identified and treated if a special program of screening were not in operation. We suggest that the present immigration policy of no screening for intestinal parasite infection be at least modified to include a recommendation that new arrivals, who are considered to be at high risk for parasite infection, be informed that an examination for parasites would be beneficial to their personal health.

Adolescent↗
PubMedDate not supplied

Evaluation of the effectiveness of immunization delivery methods.

Scientific evidence documenting the effectiveness of immunization delivery methods was summarized using the generic approach developed by the Community Health Practice Guidelines Working Group. The delivery methods examined were those for the adult and childhood vaccines of influenza, pneumococcal infection, hepatitis B, measles-mumps-rubella and diphtheria-pertussis-tetanus-polio. Based on a critical appraisal of 54 eligible comparative studies, the effects of different interventions were obtained and pooled effects were calculated for delivery methods oriented to the client, the provider and the system. The results indicate those interventions found to be most effective for each vaccine. This review of the scientific evidence of the effectiveness of immunization delivery methods provides a base for policy development and assists in the planning of resource allocation.

Adolescent↗
PubMedDate not supplied

Practice survey of immunization in Canada.

A survey was undertaken in September 1991 to document current immunization practice across Canada. Information was obtained during interviews with provincial epidemiologists and key persons involved in immunization programs and recorded on standard data collection forms. Variations in practice are described in five areas: public/private health administration; legislation; monitoring system/coverage rates/surveillance; vaccine management and costs. As changes are being considered to immunization programs, a critical examination of issues such as standardization (in coding, in assessment of waste, in assessment of coverage), surveillance systems and the use of serosurveys would be beneficial.

Canada↗
PubMedDate not supplied

Immunization delivery methods: practice recommendations.

Immunization has unequivocally contributed to large-scale reductions in mortality and morbidity due to infectious diseases. In general, consensus on the scheduling of immunizations has been achieved at the national or international level by immunization advisory committees. However, immunization delivery methods are varied and numerous. Although specific methods have been proposed, compared and evaluated, the available evidence has not been comprehensively summarized for informed public health action. This paper integrates evidence based on scientific documentation, a Canada-wide practice survey and expert opinion to formulate practice recommendations for immunization delivery methods and to identify areas for further research.

Adult↗
PubMedDate not supplied

An approach to the development of practice guidelines for community health interventions.

The Community Health Practice Guidelines (CHPG) project was initiated to develop a systematic approach to the critical evaluation of evidence on the effectiveness and efficiency of community health interventions and to the formulation of evidence-based practice recommendations. Three community health interventions--immunization delivery methods, partner notification for sexually transmitted diseases and the combination of restaurant inspection and education of food handlers--were used as prototypes to develop a standardized approach. The CHPG process consists of three components: a review of scientific evidence, a practice survey and formulation of practice guidelines. Imperatives for further development of the CHPG and define research priorities process include creating a coalition of public health organizations to sponsor the process and refining the consensus process so that the practice guidelines accurately reflect both the scientific basis of public health practice and the values of those affected.

Canada↗