Angela M.C. Rose

Meningitis serogroup W135 outbreak, Burkina Faso, 2002.

In 2002, the largest epidemic of Neisseria meningitidis serogroup W135 occurred in Burkina Faso. The highest attack rate was in children <5 years of age. We describe cases from 1 district and evaluate the performance of the Pastorex test, which had good sensitivity (84%) and specificity (89%) compared with culture or PCR.

Meningitis Dipstick Rapid Test: Evaluating Diagnostic Performance during an Urban Neisseria meningitidis Serogroup A Outbreak, Burkina Faso, 2007

Meningococcal meningitis outbreaks occur every year during the dry season in the “meningitis belt” of sub-Saharan Africa. Identification of the causative strain is crucial before launching mass vaccination campaigns, to assure use of the correct vaccine. Rapid agglutination (latex) tests are most commonly available in district-level laboratories at the beginning of the epidemic season; limitations include a short shelf-life and the need for refrigeration and good technical skills. Recently, a new dipstick rapid diagnostic test (RDT) was developed to identify and differentiate disease caused by meningococcal serogroups A, W135, C and Y. We evaluated the diagnostic performance of this dipstick RDT during an urban outbreak of meningitis caused by N. meningitidis serogroup A in Ouagadougou, Burkina Faso; first against an in-country reference standard of culture and/or multiplex PCR; and second against culture and/or a highly sensitive nested PCR technique performed in Oslo, Norway. We included 267 patients with suspected acute bacterial meningitis. Using the in-country reference standard, 50 samples (19%) were positive. Dipstick RDT sensitivity (N = 265) was 70% (95%CI 55–82) and specificity 97% (95%CI 93–99). Using culture and/or nested PCR, 126/259 (49%) samples were positive; dipstick RDT sensitivity (N = 257) was 32% (95%CI 24–41), and specificity was 99% (95%CI 95–100). We found dipstick RDT sensitivity lower than values reported from (i) assessments under ideal laboratory conditions (>90%), and (ii) a prior field evaluation in Niger [89% (95%CI 80–95)]. Specificity, however, was similar to (i), and higher than (ii) [62% (95%CI 48–75)]. At this stage in development, therefore, other tests (e.g., latex) might be preferred for use in peripheral health centres. We highlight the value of field evaluations for new diagnostic tests, and note relatively low sensitivity of a reference standard using multiplex vs. nested PCR. Although the former is the current standard for bacterial meningitis surveillance in the meningitis belt, nested PCR performed in a certified laboratory should be used as an absolute reference when evaluating new diagnostic tests.

Social distribution of diabetes, hypertension and related risk factors in Barbados: a cross-sectional study

Objective To describe the distribution of diabetes, hypertension and related behavioural and biological risk factors in adults in Barbados by gender, education and occupation. Design Multistage probability sampling was used to select a representative sample of the adult population (≥25 years). Participants were interviewed using standard questionnaires, underwent anthropometric and blood pressure measurements, and provided fasting blood for glucose and cholesterol measurements. Standard WHO definitions were used. Data were weighted for sampling and non-response, and were age and sex standardised to the 2010 Barbados population. Weighted prevalence estimates were calculated, and prevalence ratios were calculated for behavioural and biological risk factors by demographic and socioeconomic group. Results Study response rate was 55.0%, with 764 women, 470 men. Prevalence of obesity was 33.8% (95% CI 30.7% to 37.1%); hypertension 40.6% (95% CI 36.5% to 44.9%); and diabetes 18.7% (95% CI 16.2% to 21.4%). Compared with women, men were less likely to be obese (prevalence ratio 0.5; 95% CI 0.4 to 0.7), or physically inactive (0.5; 0.4 to 0.6), but more likely to smoke tobacco (4.1; 2.5 to 6.7) and consume large amounts of alcohol in a single episode (4.6; 2.7 to 7.6). Both diabetes (0.83; 0.65 to 1.05) and hypertension (0.89; 0.79 to 1.02) were lower in men, but not significantly so. In women, higher educational level was related to higher fruit and vegetable intake, more physical activity, less diabetes and less hypercholesterolaemia (p 0.01–0.04). In men, higher education was related only to less smoking (p 0.04). Differences by occupation were limited to smoking in men and hypercholesterolaemia in women. Conclusions In this developing country population, sex appears to be a much stronger determinant of behavioural risk factors, as well as obesity and its related risks, than education or occupation. These findings have implications for meeting the commitments made in the 2011 Rio Political Declaration, to eliminate health inequities.

Field Evaluation of Two Rapid Diagnostic Tests for Neisseria meningitidis Serogroup A during the 2006 Outbreak in Niger

The Pastorex® (BioRad) rapid agglutination test is one of the main rapid diagnostic tests (RDTs) for meningococcal disease currently in use in the “meningitis belt”. Earlier evaluations, performed after heating and centrifugation of cerebrospinal fluid (CSF) samples, under good laboratory conditions, showed high sensitivity and specificity. However, during an epidemic, the test may be used without prior sample preparation. Recently a new, easy-to-use dipstick RDT for meningococcal disease detection on CSF was developed by the Centre de Recherche Médicale et Sanitaire in Niger and the Pasteur Institute in France. We estimate diagnostic accuracy in the field during the 2006 outbreak of Neisseria meningitidis serogroup A in Maradi, Niger, for the dipstick RDT and Pastorex® on unprepared CSF, (a) by comparing each tests sensitivity and specificity with previously reported values; and (b) by comparing results for each test on paired samples, using McNemars test. We also (c) estimate diagnostic accuracy of the dipstick RDT on diluted whole blood. We tested unprepared CSF and diluted whole blood from 126 patients with suspected meningococcal disease presenting at four health posts. (a) Pastorex® sensitivity (69%; 95%CI 57–79) was significantly lower than found previously for prepared CSF samples [87% (81–91); or 88% (85–91)], as was specificity [81% (95%CI 68–91) vs 93% (90–95); or 93% (87–96)]. Sensitivity of the dipstick RDT [89% (95%CI 80–95)] was similar to previously reported values for ideal laboratory conditions [89% (84–93) and 94% (90–96)]. Specificity, at 62% (95%CI 48–75), was significantly lower than found previously [94% (92–96) and 97% (94–99)]. (b) McNemars test for the dipstick RDT vs Pastorex® was statistically significant (p<0.001). (c) The dipstick RDT did not perform satisfactorily on diluted whole blood (sensitivity 73%; specificity 57%). Sensitivity and specificity of Pastorex® without prior CSF preparation were poorer than previously reported results from prepared samples; therefore we caution against using this test during an epidemic if sample preparation is not possible. For the dipstick RDT, sensitivity was similar to, while specificity was not as high as previously reported during a more stable context. Further studies are needed to evaluate its field performance, especially for different populations and other serogroups.

Gastro-enteritis outbreak among Nordic patients with psoriasis in a health centre in Gran Canaria, Spain: a cohort study

BackgroundBetween November 2 and 10, 2002 several patients with psoriasis and personnel staying in the health centre in Gran Canaria, Spain fell ill with diarrhoea, vomiting or both. Patient original came from Norway, Sweden and Finland. The patient group was scheduled to stay until 8 November. A new group of patients were due to arrive from 7 November.MethodsA retrospective cohort study was conducted to assess the extent of the outbreak, to identify the source and mode of transmission and to prevent similar problems in the following group.ResultsAltogether 41% (48/116) of persons staying at the centre fell ill. Norovirus infection was suspected based on clinical presentations and the fact that no bacteria were identified. Kaplan criteria were met. Five persons in this outbreak were hospitalised and the mean duration of diarrhoea was 3 days. The consequences of the illness were more severe compared to many other norovirus outbreaks, possibly because many of the cases suffered from chronic diseases and were treated with drugs reported to affect the immunity (methotrexate or steroids).During the two first days of the outbreak, the attack rate was higher in residents who had consumed dried fruit (adjusted RR = 3.1; 95% CI: 1.4–7.1) and strawberry jam (adjusted RR = 1.9; 95% CI: 0.9–4.1) than those who did not. In the following days, no association was found. The investigation suggests two modes of transmission: a common source for those who fell ill during the two first days of the outbreak and thereafter mainly person to person transmission. This is supported by a lower risk associated with the two food items at the end of the outbreak.ConclusionsWe believe that the food items were contaminated by foodhandlers who reported sick before the outbreak started. Control measures were successfully implemented; food buffets were banned, strict hygiene measures were implemented and sick personnel stayed at home >48 hours after last symptoms.

Exploring breast cancer screening barriers among Barbadian women: a focus group study of mammography in a resource-constrained setting

Breast cancer affects women worldwide. Early detection strategies, notably mammography, aim to reduce mortality from breast cancer. However, mammography is a costly screening tool, generates controversy in terms of its impact and adverse effects, and its uptake remains low among some populations. This qualitative study (12 focus groups with 110 participants) explored experiences with mammography among Barbadian women by investigating how barriers are negotiated in a setting of resource-constrained health care provision without a national screening programme. The study findings indicate that, firstly, Barbadian women have to actively seek understanding of both breast cancer and the mammography process. Women described how, with little public awareness and knowledge, they borrow from available public health information on diabetes and HIV/AIDS to give meaning to mammographic screening. Secondly, many women expressed their fear about mammography and its potential consequences, such as experiencing social stigma and losing a romantic relationship after diagnosis. Thirdly, the cost of screening for women who opted for the more reliable private facilities was discussed, along with the potential cost of health care following a diagnosis and the emotional cost of enduring the societal taboo of breast cancer. If breast cancer screening is to be acceptable for this or similar populations, there should be provision of additional services to ensure better access to free screening or alternative strategies, as well as post-diagnostic social and financial support. The policies to develop these services must also address women’s concerns about screening and breast cancer, and provide comprehensive information to allow informed decisions about screening.

Feasibility of an electrostimulation system treatment for wound healing: a case series of patients with chronic ulcers in Barbados

Major advances have been made in the development of new therapies for chronic wounds. Fenzian™, an electrostimulation system (ES), has been clinically used for a variety of conditions. The ES was recently tested in the Barbadian population for tolerability and acceptability by asthma patients, with encouraging results. Barbados has an estimated 170 people with diabetes having some form of lower‐extremity amputation annually. Here, we describe a case series of 21 chronic ulcer patients with diabetes recruited as inpatients (n = 10) and outpatients (n = 11) in a pilot study to evaluate the feasibility and acceptability of ES in the Barbadian population. Results showed statistically significant improvement among those in the inpatient‐ versus outpatient‐recruited group for wound perimeter (P = 0·04), wound surface area (P = 0·03) and wound volume (P = 0·08). We also demonstrate that the improvement continued after cessation of ES treatment. Participants reported increased levels of pain at the end of treatment, and there was no statistically significant change in the reported quality of life. Our results showed greater improvements in reduction of ulcer size for participants from the inpatient‐ versus outpatient‐recruited group.

Predicting the burden of acute myocardial infarction in a country with limited resources: combining data from routine sources

BACKGROUND Prior to implementation of a national surveillance system for cardiovascular disease in Barbados, a small island state with limited health resources, the national burden of acute myocardial infarction (MI) was unknown. METHODS We retrospectively estimated national acute MI incidence rates (IRs) per 100,000 during the decade before registry implementation (1999-2008), using easily accessible routine data from different sources, assessing changes over time through Poisson regression. Future events (2009-2013) were estimated using simple sensitivity analysis to incorporate prediction uncertainty. Model predictions were compared with actual IRs from initial years of the registry. RESULTS In 2000, crude IR was 85.5 (95% CI: 74.9-97.2), rising to 92.1 (81.2-103.9) in 2008. Accounting for population ageing, the model anticipated IR of 115.9 in 2010 (99.7-132.1), vs actual crude IR 129.7 (115.9-144.6). CONCLUSIONS Despite no electronic medical record system in Barbados, data were simple to collect, and provided a rough baseline for acute MI burden. We show that, in countries with small populations, limited resources and in absence of surveillance, national mortality statistics and routine hospital data can be combined to adequately model national estimates of acute MI incidence. This cheap and simple, yet fairly accurate method could be a key tool for other low-resource countries with ageing populations and increasing cardiovascular disease levels.

A comparison of outcome for stroke patients in Barbados and South London

Background and aims Little is known about the poststroke outcome in Caribbean populations. We investigated differences in the activities of daily living, level of social activities, living circumstances and survival for stroke patients in Barbados and London. Methods Data were collected from the South London Stroke Register and the Barbados Register of Strokes for patients with a first-ever stroke registered between January 2001 and December 2004. The ability to perform activities of daily living was measured by the Barthel Index and level of social activities by the Frenchay Activities Index. Living circumstances were categorised into private household vs. institutional care. Death and dependency, activities of daily living and social activities were assessed at three-months, one- and two-years using logistic regression, adjusted for differences in demographic, socioeconomic and stroke severity characteristics. Results At three-months, a high level of social activities was more likely for the Barbados Register of Strokes (odds ratio 1·84; 95% confidence interval 1·03–3·29); there were no differences in activities of daily living; and Barbados Register of Strokes patients were less likely to be in institutional care (relative risk ratio 0·38; 95% confidence interval 0·18–0·79). Following adjustment, Barbados Register of Strokes patients had a higher risk of mortality at three-months (relative risk ratio 1·85; 95% confidence interval 1·03–3·30), one-year (relative risk ratio 1·83; 95% confidence interval 1·08–3·09) and two-years (relative risk ratio 1·82; 95% confidence interval 1·08–3·07). This difference was due to early poststroke deaths; for patients alive at four-weeks poststroke, survival thereafter was similar in both settings. Conclusions In Barbados, there was evidence for a healthy survivor effect, and short-term social activity was greater than that in the South London Stroke Register.

Prevalence and phenotype of diabetes and prediabetes using fasting glucose vs HbA1c in a Caribbean population.

BACKGROUND Both fasting plasma glucose (FPG) and HbA1c are recommended for the diagnosis of diabetes and prediabetes by the American Diabetes Association (ADA), and for diabetes by the World Health Organization. The ADA guidance is influential on clinical practice in many developing countries, including in the Caribbean and Latin America. We aimed to compare the prevalence and characteristics of individuals identified as having diabetes and prediabetes by FPG and HbA1c in a predominantly African ancestry Caribbean population. METHODS A representative population-based sample of 1234 adults (≥25 years of age) resident in Barbados was recruited. Standard methods with appropriate quality control were used to collect data on height, weight, blood pressure, fasting lipids and history of diagnosed diabetes, and to measure fasting glucose and HbA1c. Those with previously diagnosed diabetes (n = 192) were excluded from the analyses. Diabetes was defined as: FPG ≥7.0 mmol/L or HbA1c ≥6.5%; prediabetes as: FPG ≥5.6 to <7mmol/L or HbA1c ≥5.7 to <6.5%. RESULTS Complete data were available on 939 participants without previously diagnosed diabetes. The prevalence of undiagnosed diabetes was higher, but not significantly so, by HbA1c (4.9%, 95% CI 3.5, 6.8) vs FPG (3.5%, 2.4, 5.1). Overall 79 individuals had diabetes by either measure, but only 21 on both. The prevalence of prediabetes was higher by HbA1c compared to FPG: 41.7% (37.9, 45.6) vs 15.0% (12.8, 17.5). Overall 558 individuals had prediabetes by either measure, but only 107 on both. HbA1c, but not FPG, was significantly higher in women than men; and FPG, but not HbA1c, was significantly associated with raised triglycerides and low HDL cholesterol. CONCLUSION The agreement between FPG and HbA1c defined hyperglycaemia is poor. In addition, there are some differences in the phenotype of those identified, and HbA1c gives a much higher prevalence of prediabetes. The routine use of HbA1c for screening and diagnosis in this population would have major implications for clinical and public health policies and resources. Given the lack of robust evidence, particularly for prediabetes, on whether intervention in the individuals identified would improve outcomes, this approach to screening and diagnosis cannot be currently recommended for this population.