Showing papers by "Blaise Genton published in 1994"

Relationship Between Humoral Response to Plasmodium falciparum Merozoite Surface Antigen-2 and Malaria Morbidity in a Highly Endemic Area of Papua New Guinea

Abstract: The prevalence and concentration of antibodies to merozoite surface antigen-2 (MSA-2) were measured in blood samples collected during a cross-sectional survey. Antibodies were measured by enzyme-linked immunosorbent assay using two recombinant proteins that closely approximated the full-length mature MSA-2 polypeptides expressed by the Plasmodium falciparum isolate FC27 and the cloned line 3D7 and that were representative of the dimorphic forms of MSA-2. Antibodies were also measured to a form of the 3D7 MSA-2 lacking the central repetitive sequences (d3D7). High antibody prevalence was observed to all three antigens: the overall prevalence of IgG to FC27, 3D7, and d3D7 was 91%, 90%, and 90%, respectively. The majority of individuals ≥ 5 years of age had antibodies to both forms of MSA-2. The geometric mean antibody units increased with age with a plateau being reached by 15–20 years of age. There was a significant positive association of antibody prevalence with both the presence of the parasite and an enlarged spleen in children. This study provides the first evidence that antibodies against nonrepeat regions of MSA-2 are associated with fewer fever episodes and less anemia, both known to be indicators of malaria morbidity.

Specialized Travel Consultation Part I: Travelers' Prior Knowledge.

Abstract: Background. Studies have shown that more than one third of all travelers to tropical countries experience an illness while abroad. Naivete about diseases, such as malaria, travelers' diarrhea, cholera, and HIV infections, appears to be the most crucial factor determining travel-related morbidity rates. A study was designed both to evaluate the level of disease-related, pretravel knowledge prior to a specialized travel clinic consultation as well as to correlate the level of knowledge with demographic and travel variables and previous travel experience. Methods. Using a self-administered questionnaire, data were collected from 167 clients who attended the Hospital for Tropical Diseases Travel Clinic, London, England, in June 1991. The questionnaire evaluated clients' knowledge and attitudes of travelrelated diseases, their prevention and treatment, and the scores were analyzed using the Statistical Analysis System software, Version 5. Predictors for increased knowledge scores were examined by a one-way layout model comparing disease knowledge scores with variables such as sex, age, socioeconomic class, ethnic background, previous travel experience, type and duration of travel, destination, accommodation quality, and health insurance coverage. A step-down regression model was constructed to control for the effects of the many mutually confounding factors. Results. Travelers' diarrhea and malaria risk at destination were acknowledged by more than 85% of the respondents, and 60% of the questions on travelers' diarrhea prevention, compared to 81% of those on malaria prevention, were answered correctly. Significantly, however, only one half of the respondents indicated that they would take appropriate measures concerning diarrhea while abroad. Stepwise regression identified previous travel experience, pretravel advice, traveling for work purposes, and using backpack overland tours as significant predictors of high knowledge. Conclusions. This study points out the necessity of pretravel education and that it should focus not only on malaria but also on other travel-related diseases like travelers' diarrhea. As well, target groups for whom more detailed information should be provided are identified, including inexperienced travelers, those using organized tours and sleeping indoors, those planning to visit friends or relatives, and those who have not received sufficient pretravel health advice.

Specialized Travel Consultation Part II: Acquiring Knowledge

Abstract: With an increase in travel to tropical countries, the need to improve the disease-risk perceptions of travelers who are either naive or given inappropriate or ineffective advice is becoming increasingly important. More widely available, specialized centers that can provide advice on tropical or travel-related diseases have been established, but their efficacy on travelers' knowledge and health has not been verified. Therefore, this study was undertaken to evaluate the impact of the service provided by a routine travel consultation at the Hospital for Tropical Diseases Travel Clinic, London, England. Self-administered questionnaires were given to 161 preconsultation and 144 postconsultation clients. The consultation included an interview covering travel plans and immunization and medical history, and advice was given on the journey, necessary immunizations, and prophylaxis. Data were analyzed using the Statistical Analytic System software and the mean differences in knowledge between pre- and postconsultation scores were correlated using the nonparametric Mann-Whitney procedure. The control of mutually confounding factors was maintained by multiple regression using the Mantel-Haenszel summary chi-square and the General Linear Model procedures. Comparison of the entry and exit scores showed a significantly improved overall knowledge of travel-related diseases in the exit, postconsultation group. Subanalysis revealed that this difference was due to an increased knowledge of malaria and its prevention and perceived risk of cholera. Knowledge about the management of diarrhea or fever, however, was not significantly improved by a consultation. Inexperienced travelers taking packaged or organized trips, and those from socioeconomic groups I and II showed the largest increase in knowledge following consultation. Our results show that a face-to-face interview for an average of 18 minutes by trained staff is an effective way of improving travelers' knowledge on certain topics. The slight improvements overall are explained by the levels of experience of travel and previously acquired knowledge of the clients in our study. Effective advice on malaria prevention and some health risks is given during an average consultation; however, there is still a need for improvement in giving information on the management of diarrhea, fever, and other travel diseases.