Tobago Population Research Articles

Prevalence of Polycystic Ovarian Syndrome (PCOS) Like Symptoms in the General Practice of an Obstetrics and Gynecological Office on the Island of Tobago: A Retrospective Chart Analysis

Introduction: Polycystic ovarian syndrome (PCOS) is one of the most common endocrinopathies found in reproductive age women. It is characterized by anovulatory infertility, menstrual dysfunction, and hirsutism. It is thought to be associated with an increased risk of metabolic aberrations, including insulin resistance, hyperinsulinism and type 2 diabetes mellitus (T2D). Due to the racial disparities associated with insulin resistance and T2D, we hypothesized that the prevalence of PCOS like symptoms would be increased on the island of Tobago where women were predominantly of Afro-Caribbean descent. Study Design: A retrospective chart review of 1000 women seen in an obstetrics and gynecological office over a 7-year period was conducted. Inclusion criteria included race, body mass index (BMI)<50, and no diagnosis of a co-morbid endocrinopathy. Of the 1000 women, 884 Afro-Caribbean women were included in the analysis. PCOS diagnosis was made based on clinical signs and symptoms verified on ultrasound. The diagnosis was considered if a patient presented with ≥2 of the following signs and symptoms: infertility after >1yr of unprotected sex; irregular menses with periods >35 d, <21 d or <6/yr; overweight/ obese (BMI>25); hirsutism; and acne. Results: Within the study population, 15.7% of participants had irregular menses, 9.2% had infertility, 4.0% had hirsutism and 0.4% developed acne. The prevalence of PCOS based on clinical diagnoses and ultrasonographic evidence was 19.7%. No statistical difference (p<0.05) was found between the two groups with regards to BMI, age and parity. When stratified by age, differences in infertility were found in the 20-24 and 35-39 year old age groups with rates at 10.5 v 18.9% and 15.4 v. 30.2%, respectively. The incidence of irregular menses also differed among age groups, with PCOS patients reporting significantly higher percentages between 30-50%. Conclusion: PCOS appears to be a common disorder on the island of Tobago with a prevalence of 19.7%. This prevalence is higher than in North American studies but is in line with data excluding biochemical analysis. As PCOS is a heterogeneous disorder with diverse phenotypes and probable ethno-genetic variations, the next step would be to further characterize the characteristics of PCOS in the Tobago population. This includes obtaining a full battery of biochemical profiles of women diagnosed with PCOS-like symptoms and the consideration of gene environment interactions including exposure to endocrine disruptors thought to be involved in the etiology of PCOS.

Cancer morbidity and mortality trends in Trinidad and Tobago (2008–2018)

PurposeCancer is a leading cause of death in the Caribbean, and the Republic of Trinidad and Tobago is no exception. Evidence suggests that cancer incidence and mortality may vary based on demographic factors across the different cancer types. This study aimed to investigate the incidence and mortality trends associated with cancer cases in Trinidad and Tobago for the period 2008–2018, across different age groups, gender, and ethnicity.MethodsData on 15,029 incident cancer cases were reported to the Dr. Elizabeth Quamina Cancer Registry between 2008 and 2018. The retrospective data were analyzed by sex, ancestry, and age, and were reported using Trinidad and Tobago population statistics for the period 2008–2018.ResultsThe incidence of prostate and breast cancers was high among males and females, respectively. Among males, the highest cancer mortality was associated with prostate, lung, colon, blood, and pancreatic cancers, respectively. Among females, the highest cancer mortality was associated with breast, ovary, colon, blood, and pancreatic cancers. The frequency of occurrence of the top five cancer sites was the highest among Afro-Trinidadians followed by Indo-Trinidadians. Most females diagnosed with breast cancer were at a localized stage, while most males diagnosed with breast cancer were at a distant or regional stage. Most individuals diagnosed with blood cancer were at a distant stage. For lung and colon cancer, the stage of diagnosis for most males and females was either distant or unknown. Majority of males are diagnosed with prostate cancer at an unknown stage.ConclusionsThe findings indicate highest cancer incidence and mortality occur among Afro-Trinidadians. The stage at diagnosis varies across cancer types and gender.

The Correlation of Papanicolaou Smears and Clinical Features to Identify the Common Risk Factors for Cervical Cancer: A Retrospective and Descriptive Study from a Tertiary Care Hospital in Trinidad.

Background: Cervical cancer, the fourth most frequent cancer in women, is associated with the human papillomavirus (HPV). This study identifies risk factors and clinical findings for abnormal cervical cytology and histopathology in the Trinidad and Tobago populations. Some risk factors include early age of first coitus, a high number of sexual partners, high parity, smoking, and using certain medications, such as oral contraception. This study aims to identify the significance of Papanicolaou (pap) smears and the common risk factors that contribute to the development of premalignant and malignant cervical lesions. Method: A three-year retrospective, descriptive study of cervical cancer was conducted at the Eric Williams Medical Sciences Complex. The subject population included 215 female patients aged 18 years and older with the following documented abnormal cervical cytology: (ASCUS), ASC-H, LSIL, HSIL, Atypical Glandular cells, HPV, Adenocarcinoma, and Invasive Squamous Cell Carcinoma. Histopathology records were analysed for thirty-three of these patients. Patients' information was recorded on data collection sheets adapted from the North Central Regional Health Authority's cytology laboratory standardised reporting format request form. Results and Findings: The data were analysed via Statistical Package for Social Sciences (SPSS) software edition 23 using frequency tables and descriptive analysis. The mean sample age of the population was 36.7 years, the first age of coitus was 18.1 years, the number of sexual partners was 3.8, and the number of live births was 2. LSIL was the most popular abnormal finding, 32.6%, followed by HSIL, 28.8%, and ASCUS, 27.4%. Most histopathological reports resulted in CIN I and II. Conclusions: The significant risk factors observed for cytology abnormalities and premalignant lesions were early age of coitus, a high number of sexual partners, and no use of contraception. Patients mostly presented as asymptomatic despite obtaining abnormal cytology results. Hence, regular pap smear screening should continue to be highly encouraged.

Health and economic burden of disease of sugar-sweetened beverage consumption in four Latin American and Caribbean countries: a modelling study

ObjectiveOverweight and obesity are important contributors to the non-communicable disease burden. The consumption of sugar-sweetened beverages (SSBs) has been associated with an increased risk of type 2 diabetes mellitus (T2DM),...

Prevalence of dental anomalies in Trinidad and Tobago. A retrospective study

ABSTRACT Background Dental anomalies entail an extensive range of disorders. This study aimed to ascertain the prevalence of several anomalies detectable on orthopantomograms and determine associations with ethnicity and gender. Methods A retrospective review of 581 orthopantomograms and patient files was conducted. The prevalence of various anomalies was determined and the differences with ethnicity and gender were calculated using the chi-square test. Results The study comprised 269(50.2%) males and 267 (49.8%) females with an age range of 5–16 years. 264(49.3%) participants were Afro-Trinidadians, 146(27.2%) were Indo-Trinidadians, and 126 (23.5%) were of mixed ethnicity. The overall prevalence of dental anomalies was 75.2%. No statistically significant correlation was found between the occurrence of dental anomalies and gender. An association was found between ethnicity and missing canines, impacted molars and other impacted teeth, and microdontia. The mixed population had more anomalies. The impacted canine was the most prevalent anomaly. 44% of participants presented with one anomaly, and 24.81% of participants had two anomalies. Conclusion There was a high prevalence of dental anomalies in the Trinidad and Tobago population. There was an association with some anomalies and ethnicity and no association with gender. The presence of dental anomalies should be considered when assessing diagnosing and treatment planning patients in this country.

EQ-5D-3L Population Norms for Trinidad and Tobago

ABSTRACT Objective Quality of life measures are increasingly being used in clinical practice and in research. Internationally EQ-5D is the most commonly used generic health related quality of life instrument. The EQ-5D system comprises five dimensions: mobility, self-care, ability to conduct usual activities, pain/discomfort and anxiety/depression. This study sought to provide a set of population norms for Trinidad and Tobago to facilitate clinical and other researchers who wish to use the EQ-5D-3L value set that was recently created for Trinidad and Tobago. Population norms are baseline values against which the EQ-5D health status of patients or patient groups can be compared. Methods Self-reported health data using the EQ-5D-3L questionnaire were taken from two previously undertaken surveys of representative samples of the Trinidad and Tobago population. EQ-5D-3L health states, mean EQ VAS (visual analogue scale) scores and mean EQ-5D-3L index values were obtained for demographic groups. Results Data were obtained for 590 respondents. The mean EQ VAS value was 82.3 and the mean EQ-5D-3L index value was 0.931. The EQ-5D dimensions with the highest rates of reported problems were pain/discomfort (29%) and anxiety/depression (14%). Self-reported health was observed to decline as age progresses and men reported higher levels of health than women. Conclusion The population norms in this study can be used as base-line values for key demographic groups in clinical practice and in clinico-economic research using EQ-5D-3L.

Expansion of frozen hybrids in the guppy ectoparasite, Gyrodactylus turnbulli.

Hybridization is one of the major factors contributing to the emergence of highly successful parasites. Hybrid vigour can play an important role in this process, but subsequent rounds of recombination in the hybrid population may dilute its effects. Increased fitness of hybrids can, however, be frozen by asexual reproduction. Here, we identify invasion of a ‘frozen hybrid’ genotype in natural populations of Gyrodactylus turnbulli, a facultatively sexual ectoparasitic flatworm that causes significant damage to its fish host. We resequenced genomes of these parasites infecting guppies from six Trinidad and Tobago populations, and found surprisingly high discrepancy in genome‐wide nucleotide diversity between islands. The elevated heterozygosity on Tobago is maintained by predominantly clonal reproduction of hybrids formed from two diverged genomes. Hybridization has been followed by spread of the hybrids across the island, implying a selective advantage compared with native genotypes. Our results thus highlight that a single outcrossing event may be independently sufficient to cause pathogen expansion.

Prevalence of Bimaxillary Protrusion: A Systematic Review

Objective: This study aimed to systematically review current relevant literature on the prevalence of bimaxillary protrusion. Materials and Methods: The electronic databases PubMed, Medline, Scopus, Google Scholar and the Cochrane Library were searched using specific inclusion criteria to obtain applicable articles. References from included studies were also examined. Results: Three articles were identified that met the inclusion criteria. Prevalence of bimaxillary protrusion ranged from 3.7% to 68.8% in different populations reported in the literature examined. GRADE assessed overall confidence was deemed to be very low. Conclusion: These results show that the prevalence of bimaxillary protrusion varies greatly between races and geographic regions. The Trinidad and Tobago population has a high prevalence of bimaxillary protrusion.

Cephalometric norms for Bimaxillary Protrusion in Trinidad and Tobago: a preliminary study

ABSTRACT The aim of this study is to establish for the first time cephalometric norms for bimaxillary protrusion in Trinidad and Tobago population and to compare findings to previously published norms for other bimaxillary protrusion groups. Materials and Methods In total, 109 standardized lateral cephalometric radiographs were taken by one investigator of bimaxillary protrusion patients prior to receiving orthodontic treatment. The sample consisted of 52 boys and 57 girls aged 10–17 years. The cephalograms were traced using 48 hard and soft tissue and 25 linear and angular cephalometric measurements. Independent sample t-test was used to assess inter-gender differences, norms were calculated. The results were then compared to the norms for other bimaxillary protrusion populations. Results The mean values and standard deviations obtained were: SNA, 85.9° (± 4.9°); SNB, 78.7°(± 4.5°); ANB, 7.2°(± 2.5°); MMPA, 32.3°(±5.1°); UI-LI,109.7° (±8.2°); UI-Max, 118.7° (±6.1°); LI-Man, 101.4° (±5.9°); LI-Apo, 3.8° (±2.6°); Upper lip to E-plane 2.0 mm (±3) and Lower Lip to E-plane 5.6 mm (±3.2).The independent t-test showed sexual dimorphism with SNA and upper and lower lip to E-plane being higher in males compared to females. The maxilla and mandible were more anteriorly placed in this sample as compared to Caucasian norms. ANB, MMPA, UI-Max, LI-Man, LI-Apo, upper lip and lower lip to E-plane, were all higher in this population compared to other bimaxillary protrusion populations. Conclusions There are some fundamental differences in the cephalometric norms for the bimaxillary protrusion population in Trinidad and Tobago and in the context of orthodontic diagnosis and treatment planning these cephalometric norms should be the yardstick.

Evaluating Cardiovascular Disease (CVD) risk scores for participants with known CVD and non-CVD in a multiracial/ethnic Caribbean sample.

BackgroundCardiovascular Disease (CVD) risk prediction models have been useful in estimating if individuals are at low, intermediate, or high risk, of experiencing a CVD event within some established time frame, usually 10 years. Central to this is the concern in Trinidad and Tobago of using pre-existing CVD risk prediction methods, based on populations in the developed world (e.g. ASSIGN, Framingham and QRISK®2), to establish risk for its multiracial/ethnic Caribbean population. The aim of this study was to determine which pre-existing CVD risk method is best suited for predicting CVD risk for individuals in this population.MethodA survey was completed by 778 participants, 526 persons with no prior CVD, and 252 who previously reported a CVD event. Lifestyle and biometric data was collected from non-CVD participants, while for CVD participants, medical records were used to collect data at the first instance of CVD. The performances of three CVD risk prediction models (ASSIGN, Framingham and QRISK®2) were evaluated using their calculated risk scores.ResultsAll three models (ASSIGN, Framingham and QRISK®2) identified less than 62% of cases (CVD participants) with a high proportion of false-positive predictions to true predictions as can be seen by positive predictabilities ranging from 78% (ASSIGN and Framingham) to 87% (QRISK®2). Further, for all three models, individuals whose scores fell into the misclassification range were 2X more likely to be individuals who had experienced a prior CVD event as opposed to healthy individuals.ConclusionThe ASSIGN, Framingham and QRISK®2 models should be utilised with caution on a Trinidad and Tobago population of intermediate and high risk for CVD since these models were found to have underestimated the risk for individuals with CVD up to 2.5 times more often than they overestimated the risk for healthy persons.

Prevalence and Occlusal Risk Factors for Fractured Incisors among 11-12-Year-Old Children in the Trinidad and Tobago Population.

This cross-sectional survey was carried out to ascertain the prevalence of fractured incisors in 11–12-year-olds. In addition we explored the relationship with overjet, incompetent lips, incisor inclination and to determine if there was any association with ethnicity and gender. All permanent incisors were examined in 672 children comprising 356 females (53.1%) and 315 males (46.9%). The sample comprised 11–12-year-olds in high schools across Trinidad and Tobago. Statistical analysis was undertaken using Chi-square test, independent t-test, and binary logistic regression. The prevalence of fractured incisors was 18.9%. Boys presented with an increased incidence of fractured incisors than girls. 86.3% of dental trauma was untreated. The average overjet of subjects with fractured incisors was 4.2 mm. 18.62% of subjects with fractured incisors had incompetent lips. The most common malocclusion (18.81%) with fractured incisors was class 2 division 1. The Afro-Trinidadian ethnicity had the highest prevalence of fractured incisors (11.0%) when compared to mixed ethnicities, which was statistically significant. Maxillary central incisors were the most commonly injured teeth. Most patients delayed in seeking dental treatment for fractured incisors in our population. Early orthodontic treatment is recommended to help reduce the risk of dental trauma.

Cross-Sectional survey to ascertain the prevalence of Molar Incisor Hypo-mineralization in the Trinidad and Tobago population

Cross-Sectional survey to ascertain the prevalence of Molar Incisor Hypo-mineralization in the Trinidad and Tobago population

A new species of Erythrolamprus from the oceanic island of Tobago (Squamata, Dipsadidae).

Tobago is a small island on the southeast edge of the Caribbean Plate with a continental flora and fauna. Using DNA sequences from Genbank, new sequences, and morphological data from the snakes Erythrolamprusepinephalus, E.melanotus, E.reginae, and E.zweifeli, the species status of specimens of a Tobago snake previously considered to be Erythrolamprusreginae was assessed. Erythrolampruszweifeli, long considered a subspecies of E.reginae, was found to be a northern Venezuela-Trinidad endemic and the sister to E.reginae. The trans-Andean species E.epinephalus is shown to be non-monophyletic while the Costa Rican lineage of E.epinephalus is weakly supported as the sister to the Tobago population. The Tobago Erythrolamprus is described as a distinct taxon based upon five specimens from four localities in lower montane rainforest. Much of the new species range includes the Main Ridge Forest Reserve of Tobago, the oldest protected forest in the Western Hemisphere. All known locations fall within a 400-ha area, and its total geographic distribution is likely to be less than 4,566 ha. The restricted distribution of this new snake makes it a likely candidate for threatened status. The new species also becomes another biogeographic link between northern Venezuela and Tobago.

The Cost of a Healthy Diet in Trinidad and Tobago

BackgroundThe chronic non‐communicable diseases (diabetes mellitus, hypertension, cancers and cardiovascular diseases) are major contributors to adult illness and death locally. In fact, diabetes mellitus and hypertension account for over half of all annual visits to local healthcare facilities. Healthy dietary practices play important roles in the prevention and management of these diseases. In this study, we evaluated the cost of consuming diets that are consistent with good health.MethodsThe study was a cross‐sectional in nature. Participants (18–65 years) completed a self‐administered questionnaire consisting of socio‐demographic, physical activity and a food frequency questionnaire. The food frequency questionnaire was designed to capture the usual dietary intake of the Trinidad and Tobago population over a one month period. For each food example of serving sizes were given. Serving sizes were multiplied by frequency to estimate the amount the food item consumed. These were converted to number serving per day. For each individual the serving sizes for foods consumed were entered in to the Nutrigenie 7 (Optimum Nutrition Software) and analysed for nutrients and calories. This software uses the 2002–2005 Institute of Medicine (IOM) Dietary Reference Intakes for nutrients and calories to rate overall diet quality. It ranks the overall diet by assigning a star rating from 1 to 5, with 1 being the lowest in quality. A star rating of 3 or more suggests that the diet has met or exceeded the level for acceptability. Anthropometry was self‐reported with 10% of the population having measurements done according to recommended procedures. The Scofield equation was used to determine basal metabolic rate (BMR). The Goldberg ratio of reported energy intake to BMR was used to determine the level of plausible reporting. Plausible reporters were categorised with a cut‐off point where energy intakes that were 1.21 to 2.39 times BMR. All participation was voluntary. The University of the West Indies Ethics Committee approved the study.ResultsEleven Thousand Seven Hundred and Eighty persons participated in the study. Approximately 67% (Females = 4549; Male = 3,300) met the Goldberg criteria for plausible reporting of energy intakes. Based on the Goldberg criteria for plausibility males had significantly higher intakes of calories (2223 ± 652 Kcal vs 1987 ± 594 Kcal; P, 0.001). Forty‐three percent of participants consumed diets that had adequate levels of vitamins while 72.2 had adequate levels of mineral intakes. Only 37% of participants met the IOM of Medicine 2002–2005 criteria for dietary adequacy. Mean BMI was 23.9 ± 4.9 with 36% of participants being overweight and obese. Our calculations revealed that persons consuming a healthy diet (≥ 3 stars) would have to spend on average 10 TT dollars (1.50 US) dollars per day compared to those consuming less healthy diets.ConclusionThe cost of improving diets to ensure compliance with the IOM standards is approximately 45 US dollars per month or 540 US dollars per year. For a family of 4 persons this would represent a substantial cost. This could be easily offset by the cultivation of fruits and vegetables as part of a home garden.Support or Funding InformationNone

Microcytosis and Alpha and Beta Thalassaemia in Prospective Blood Donors of East Indian Descent in Trinidad and Tobago

Background: People of East Indian descent account for 40% of the Trinidad and Tobago (TT) population. Most came from Uttar-Pradesh and West Bengal in India where thalassaemia is prevalent. The thalassaemia carrier frequency and exact mutations are unknown in TT. Diagnostic DNA analysis is not routinely available. Objective: To estimate the carrier frequency of thalassaemia among prospective blood donors. Method: Blood samples were obtained from 125 prospective blood donors of East-Indian origin. CBC was done to screen for microcytosis(MCV≤83 fL). Microcytic samples had ferritin, transferrin saturation, haemoglobin electrophoresis, haemoglobin A2/F quantification and DNA analysis performed performed for thalassaemia. Results: 72.4% subjects were male and 26.4% female. Microcytosis was found in 14 (11.2%) (9 males, 5 females). Among microcytic subjects, 11(78.6%) (8 males, 3 females) thalassaemia mutations were detected. The range MCV range was wider in β-thalassaemia (63.7-80.7 fL) than α-thalassaemia carriers (78.5-80.1 fL). All subjects with the α-globin gene mutation had the α3.7 deletion which is the commonest α-gene mutation in India. The people with β-thalassaemia mutations had IVS I-5 G/C (common in India) and IVS II-666 T/C. Conclusion: There were a high percentage of thalassaemia carriers in microcytic individuals, thus showing the importance of testing for this disorder. A larger study is needed to determine the spectrum of α- and β-thalassaemia mutations, to analyze for correlation between the degree of microcytosis and specific genotype and for useful predictors of α- and β-globin gene mutations.

Allelic background of LEPRE1 mutations that cause recessive forms of osteogenesis imperfecta in different populations

Biallelic mutations in LEPRE1 result in recessively inherited forms of osteogenesis imperfecta (OI) that are often lethal in the perinatal period. A mutation (c.1080+1G>T, IVS5+1G>T) in African Americans has a carrier frequency of about 1/240. The mutant allele originated in West Africa in tribes of Ghana and Nigeria where the carrier frequencies are 2% and 5%. By examining 200 samples from an African-derived population in Tobago and reviewing hospital neonatal death records, we determined that the carrier frequency of c.1080+1G>T was about one in 200 and did not contribute to the neonatal deaths recorded over a 3-year period of time in Trinidad. In the course of sequence analysis, we found surprisingly high LEPRE1 allelic diversity in the Tobago DNA samples in which there were 11 alleles distinguished by a single basepair variant in or near exon 5. All the alleles found in the Tobago population that were within the sequence analysis region were found in the African American population in the Exome Variant Project. This diversity appeared to reflect the geographic origin of the original population in Tobago. In 44 individuals with biallelic LEPRE1 mutations identified by clinical diagnostic testing, we found the sequence alterations occurred on seven of the 11 variant alleles. All but one of the mutations identified resulted in mRNA or protein instability for the majority of the transcripts from the altered allele. These findings suggest that the milder end of the clinical spectrum could be due to as yet unidentified missense mutations in LEPRE1.

Insular avian adaptations on two Neotropical continental islands.

AIM: Most studies of avian insular adaptations have focused on oceanic islands, which may not allow characters that are insular adaptations to be teased apart from those that benefit dispersal and colonization. Using birds on continental islands, we investigated characters that evolved in situ in response to insular environments created by late Pleistocene sea level rise. LOCATION: Trinidad and Tobago, nearby Caribbean islands and continental South America. METHODS: We weighed fresh flight muscles and measured museum skeletal specimens of seven species of birds common to the continental islands of Trinidad and Tobago. RESULTS: When corrected for body size, study species exhibited significantly smaller flight muscles, sterna and sternal keels on Tobago than on larger Trinidad and continental South America. Tobago populations were more 'insular' in their morphologies than conspecifics on Trinidad or the continent in other ways as well, including having longer bills, longer wings, longer tails and longer legs. MAIN CONCLUSIONS: We hypothesize that the longer bills enhance foraging diversity, the longer wings and tails compensate for the smaller pectoral assemblage (allowing for retention of volancy, but with a probable reduction in flight power and speed), and the longer legs expand perching ability. Each of these differences is likely to be related to the lower diversity and fewer potential predators and competitors on Tobago compared with Trinidad. These patterns of smaller flight muscles and larger bills, legs, wings and tails in island birds are not the results of selection for island dispersal and colonization, but probably arose from selection pressures acting on populations already inhabiting these islands.

Characterisation of DDT and Pyrethroid Resistance in Trinidad and Tobago populations ofAedes aegypti

Insecticide resistance is an important factor in the effectiveness of Aedes aegypti control and the related spread of dengue. The objectives of this study were to investigate the status of the organochlorine dichlorodiphenyltrichloroethane (DDT) and pyrethroid (permethrin and deltamethrin) resistance in Trinidad and Tobago populations of Ae. aegypti and the underlying biochemical mechanisms. Nine populations of Ae. aegypti larvae from Trinidad and Tobago were assayed to DDT and PYs using the Centers for Disease Control and Prevention (CDC) time-mortality-based bioassay method. A diagnostic dosage (DD) was established for each insecticide using the CAREC reference susceptible Ae. aegypti strain and a resistance threshold (RT), time in which 98-100% mortality was observed in the CAREC strain, was calculated for each insecticide. Mosquitoes which survived the DD and RT were considered as resistant, and the resistance status of each population was categorised based on the WHO criteria with mortality <80% indicative of resistance. Biochemical assays were conducted to determine the activities of α and β esterases, mixed function oxidases (MFO) and glutathione-S-transferases (GST) enzymes which are involved in resistance of mosquitoes to DDT and PYs. Enzymatic activity levels in each population were compared with those obtained for the CAREC susceptible strain, and significant differences were determined by Kruskal-Wallis and Tukey's non-parametric tests (P<0.05). The established DDs were 0.01 mg l(-1), 0.2 mg l(-1) and 1.0 mg l(-1) for deltamethrin, permethrin and DDT, respectively; and the RTs for deltamethrin, permethrin and DDT were 30, 75 and 120 min, respectively. All Ae. aegypti populations were resistant to DDT (<80% mortality); two strains were incipiently resistant to deltamethrin and three to permethrin (80-98% mortality). Biochemical assays revealed elevated levels of α-esterase and MFO enzymes in all Ae. aegypti populations. All, except three populations, showed increased levels of β-esterases; and all populations, except Curepe, demonstrated elevated GST levels.Metabolic detoxification of enzymes is correlated with the manifestation of DDT and PY resistance in Trinidad and Tobago populations of Ae. aegypti. The presence of this resistance also suggests that knock down (kdr)-type resistance may be involved, hence the need for further investigations. This information can contribute to the development of an insecticide resistance surveillance programme and improvement of resistance management strategies aimed at combatting the spread of dengue in Trinidad and Tobago.

Organophosphate Resistance in Trinidad and Tobago Strains of Aedes aegypti

Aedes aegypti larvae from 8 sites in Trinidad and 1 in Tobago were assayed against temephos, malathion, and fenthion using the Centers for Disease Control and Prevention time-mortality-based bioassay method. Resistance ratios (RRs) and resistance thresholds (RTs) for each insecticide were calculated in relation to the Caribbean Epidemiology Center reference susceptible strain. Results showed that the Haleland Park and Tobago strains were susceptible to fenthion and malathion, respectively (RRs < 1), while the San Fernando strain had a high RR (33.92) to malathion. All other strains had low-level resistance to fenthion and malathion. Resistance to temephos was more intense with 4 strains showing high-level resistance. The established RT was 60 min for fenthion, 75 min for bendiocarb, and 120 min for temephos and malathion. At the RTs, all Trinidad strains were resistant to temephos (11.50-74.50% mortality), 7 resistant to fenthion (21.25-78.75% mortality), and 5 resistant to malathion (56.25-77.50% mortality). The other strains were incipiently resistant (80-97% mortality). Despite the discrepancies between the RR levels and RT status, it is evident that the organophosphate insecticide resistance is prevalent in Trinidad and Tobago populations of Ae. aegypti. These results suggest that operational failure could soon occur and alternative strategies should be developed and implemented to reduce the probability of further selection pressure on resistant Ae. aegypti populations in Trinidad and Tobago.

An evaluation of the intensive care unit resources and utilization in trinidad

To evaluate resources and utilization of Intensive Care Units in Trinidad and Tobago. This was a prospective observational study to evaluate Intensive Care Units (ICU) of three public and two private hospitals in Trinidad with respect to their infrastructure, process of care and patient outcome. Structure of ICUs was assessed by interviews and personal observations. A Cost Block Model was used to determine the expenditure for ICUs. The process of ICU was assessed by Therapeutic Intervention Scoring System (TISS-28). For outcome evaluation, two prognostic scoring systems namely Simplified Acute Physiology Score (SAPS II) and Paediatric Index of Mortality-2 (PIM-2) were used The total number of ICU beds was 27. The overall bed occupancy was 66.2%. One hundred and eighteen patients consecutively admitted to ICU during a two-month period were enrolled for process and outcome evaluation. The overall median age of patients was 44 years [Interquartile range (IQR) 25, 59]. The mean cost per patient in the public hospitals was TT $64,746 compared to $77,000 in a private hospital. The average total daily TISS per patient was 27.01 +/- 5.4 (SD). The median length of stay was five days (IQR 2, 9). The overall predicted mortality was 32.9%, the observed mortality was 29.7% and thus the standardized mortality ratio (SMR) was 0.9. The overall bed availability in ICUs with respect to Trinidad and Tobago's population and case-mix is low compared to developed countries, although the process of ICU care is comparable. Outcome of patients was good in terms of risk-adjusted mortality. The study highlights the need to further increase bed-strength and optimize the resource utilization of ICUs in Trinidad and Tobago.