A comparison of surveillance systems for the dengue vector Aedes aegypti in Port of Spain, Trinidad

When the currently used larval surveillance system (visual inspection) for the dengue vector Aedes aegypti was compared with the surveillance for the presence of eggs by ovitrapping in Port of Spain, Trinidad, it was found that the latter (39.1 percent) was significantly more sensitive than the visual inspection system (10.1 percent). At the same time, the presence of the nuisance mosquito Culex quinquefasciatus was detected in 38.4 percent of the households. Both Ae. aegypti and Cx. quinquefasciatus showed preference for ovipositional attractants in ovitraps: hay infusion > yeast suspension > plain tap water. Although all the socioeconomic and geographic areas produced both mosquito species in 1996, upper middle class (UMC) areas (8.6-43.4 percent), produced more Ae. aegypti than did lower middle class (LMC) area 7.8-38.8 percent), which produced more than working class (WC) areas (3.9-29.9 percent). For Cx. quinquefasciatus, the order of production was reversed with WC areas (50.1 percent) > LMC areas (30.0 percent) > UMC areas (26.0 percent). Change in vector surveillance strategies incorporating some ovitrapping and stratified sampling are recommended for Caribbean countries(AU)

A longitudinal study of the persence of gastrointestinal tract parasitic infections in children of St. Kitts over the 15-year period, 1982-1997

When 188 (1962), 266 (1991) and 222 (1997) five and nine year old children in St. Kitts were assessed for the presence of parasitic infections, there were significant reductions in the prevalence of trichurias from 83 percent through 58 percent to 27 percent, of ascariasis from 24 percent through 8.6 percent to 0.9 percent and of giardiasis from 15 percent through 9.4 percent to 5 percent, respectively; over the 15 year period. Anthelminthic use, which appeared to be the most important responsible intervention tool, remained roughly at the same level at 59-51 percent. However, the types of anthelminthics used changed over the period. Piperazine citrate, which was used by 66 percent in 1982, had only 35 percent usage in 1991 and 11.3 percent in 1197. Albendazole, which was not used at all in 1982, was taken by 32 percent of the children in 1991 and 45.9 percent in 1997, and at the same time use of laevo-tetramisole increase by 20 percent in 1991 from 14 percent in 1982, to 42.9 percent in 1997. Details are given of a proposed island-wide parasitic infection with the assistance of identified private and public sector partners.(AU)

Surveillance for rubella and congenital rubella syndrome in the Caribbean and costing the burden of disease - abstract

Subsequently to the "BIG BANG" catch up measles vaccination campaign that was conducted in the sub-region during 1991, very low rubella incidence rates (<2.0 cases per 100,000 population) were recorded during the years 1992 through 1995. Beginning in 1995, however, and continuing through 1997, sizeable outbreaks of rubella have occurred in Jamaica, Barbados, Trinidad and Tobago, Guyana, and Belize. Subregional rubella incidence rates increased to 10.3 cases per 100,000 population in 1996 and a prototype surveillance system for congenital rubella syndrome (CRS) was developed and disseminated to all CAREC member countries in 1996. Analysis of surveillance data indicates that nearly half (47.1 percent) of these reported cases were diagnosed at birth. Intrauterine growth retardation and cataracts appear to be the predominant clinical manifestations. The maternal age distribution of CRS case (18-37 years) supports the hypothesis that we have not as yet increased our rubella vaccination coverage among women of child bearing age to prevent CRS and our use of Measles-Mumps-Rubelle vaccine in infant populations has been too recent to confer any significant benefit to such women. Direct costs alone associated with the care of an infant with CRS in Trinidad and Tobago are conservatively estimated at US$20,000 annually. These as well as indirect costs are, however, eminently avoidable. The costs of an immunisation campaign would have to exceed the hundreds of thousands spent on CRS care before an immunisation effort would fail to be beneficial. Expenditure of one half of what this syndrome cost might have prevented it altogether.(AU)

Entrance qualifications and student performance in a hybrid problem bases and traditional medical programme

A hybrid problem based learning (PBL) and traditional programme was started at the Trinidad campus of the University of the West Indies in 1989. Analyses were carried out to determine the extent to which the entrance qualifications of the students were related to their performances at the examinations in the Phase I (preclinical and paraclinical) and Phase II (clinical) programmes. Students who were admitted on the basis of their results in the secondary school General Certificate of Examination (GCE), "A" level scored higher at the Phase I, but not at the Phase II, level than those who already had university education. Among the "A" level students, there was positive correlation between the total "A" level scores and the examination marks in the medical programme, particularly at the Phase I level. Futhermore, multiple regression analyses indicated that the grades in "A" level chemistry and, to a lesser extent in biology, had the most influence on performance at the Phase I examinations, with much less influence on performances at the Phase II examinations. These results suggest that good grades at "A" level examination are significant factors, but not the only important ones, that favour high achievement in the initial stages of this type of PBL/traditional medical programme.(AU)

The incidence of prostate cancer-trends in two ethnic groups in Trinidad: a nine year study - abstract

Data on prostate cancer patients were obtained from the Pathology Department, General Hospital, San Fernando (before 1993) and, after 1993, prospectively collected for all admissions to that hospital for all patients with prostate cancer. Additonal data was collected from the hospital theatre registers and medical records. 365 prostate patients' data over the nine year period 1987-1995 were analysed for tends in the disease. In the population served by the hospital there are equal numbers of East Indians and Africans in the age range > 60 years. There was a rapid rise in the incidence of prostate cancer in males > 60 years starting in 1993, when PSA became widely available. This rise was maintained and seen mainly in the African population though there was a lesser rise among the East Indians. In most years, prostate cancer was more frequent in African than East Indian men. These data emphasize the value of PSA in detecting prostate cancer in both races but there is need for more education and systematic screening programmes to detect the asymptomatic male who can be offered curative therapy. The significantly higher frequency of prostate cancer in Africans (87.2 percent) than East Indians (12.8 percent) may be associated with differences with genetic and dietary factors and not with environment which is the same for both races. (AU))

A comparison of surveillance systems for the dengue vector, Aedes aegypti, in Port of Spain, Trinidad - abstract

When the currently used larval surveillance system (visual inspection) for the dengue vector Aedes aegypti (Linn.) was compared with the surveillance for the presence of gravid females by ovitrapping in Port-of-Spain, Trinidad, it was found that the latter (39 percent) was significantly (p<0.001) more sensitive than the visual inspection system (10 percent). At the same time, the presence of the nuisance mosquito Culex quinquefasciatus (Say) was detected in 38 percent of the households. Both Ae. aegypti and Cx. quinquefasciatus showed preference for ovipositional attractants in ovitraps: hay infusion > yeast suspension > plain tap water (p,0.001). While the socio-economic and geographical areas produced both mosquito species in 1996, upper middle class (UMC) areas (35- 25 percent) produced more Ae. aegypti than lower middle class (LMC) areas (32- 37 percent), which produced more than working class (WC) areas (28-29 percent ). For Cx. quinquefasciatus, the order of production was reversed with WC areas (44-53 percent)> LMC areas (21- 30 percent) > UMC areas (9- 27percent). Change in vector surveillance strategies incorporating some ovitrapping and stratified sampling are recommended for member countries. These data will help improve management strategies aimed at further reduction of the prevalence of these two mosquito species in urban areas. (AU)