An investigation of some risk factors for severe leptospirosis on Barbados.

Between November 1979 and the end of December 1986 (7.17 years), 248 cases of leptospirosis were confirmed among hospital patients on Barbados (mean 35 per year; range 25-57). Considering the 235 who were greater than or equal to 15 years of age, the annual incidence of leptospirosis was 19.2/100,000 population (14.0 for all age groups). There were 173 males and 62 females, and for cases aged 15-34 leptospirosis was 9.6 times more common in men than women. Among men, incidence increased fairly steadily with age, and an even steadier increase was apparent in women up to age 64, with some decline in later years. The incidence of disease was much higher among agricultural than other workers and the non-employed. Highest case numbers were recorded in the parishes of St Michael (65 or 28%) and Christ Church (36 or 15%), though the incidence was lowest in these two parishes (13.1/100,000 and 17.4/100,000, respectively). The highest incidence rates were in St Andrew and St Joseph (50.2 and 36.1/100,000, respectively). The incidence in areas with rainfall greater than or equal to 1600 mm (32.6/100,000) was nearly twice that in areas with rainfall less than 1600 mm (17.3/100,000). There is a clear link between cases of severe disease and recent rainfall. Using 134 patients greater than or equal to 15 years of age with fever due to other illnesses as controls, a higher proportion of cases than controls came from rural areas. The risk of contracting leptospirosis was increased for all categories of manual workers relative to the group at lowest risk (non-manual indoor workers). Sugar-cane workers were five times more likely to contract leptospirosis than were non-manual indoor workers, while those whose families minded livestock were 2.5 times more likely, and those with rodents in their garden/yard were 1.8 times more likely to do so. Other risk factors examined did not show significant associations with the disease. Despite increasing mechanization and the use of more protective clothing, agricultural workers are still at high risk from leptospirosis. The annual range of cases is likely to stay much as it is in the foreseeable future.

Blood pressure in blacks. Twin studies in Barbados.

We have recently reported that there are significant genetic influences on the population variation in blood pressure in black twins in Los Angeles. The present cross-sectional study was undertaken to replicate these findings in a black twin population that lives in a different biosocial environment. We chose the Caribbean island nation of Barbados, where 96% of the population is black, the literacy rate is 99%, and the access to health care is guaranteed. The goals were 1) to test the feasibility of twin studies in blood pressure research in a developing country and 2) to estimate the relative contribution of genes and environment to blood pressure variability in blacks in the Caribbean. The names of 200 twin sets were obtained with the assistance of community resources including a twin club, by media advertisement, and by asking people at public blood pressure screenings if they knew any twins. By using these methods, we identified 200 sets of twins. Of these, 37.5% (75/200) met our criteria for study. Although 97% of the sets of twins (73/75) said they were willing to participate, only 69% (52/75) were able to be scheduled during the 1 week of the study when the full team of investigators was in Barbados. Of those scheduled, 83% (43/52) were examined. Examination included medical history, physical examination, recumbent blood pressure measurements by two observers, anthropometric measurements, 24-hour urine collections for sodium and potassium tests, and blood tests for zygosity.(ABSTRACT TRUNCATED AT 250 WORDS)

Leptospirosis in Barbados. A clinical study.

A 39-month clinical study of leptospirosis was undertaken at the Queen Elizabeth Hospital, Barbados. Eighty-eight patients had a confirmed diagnosis of the disease during the period. The major serogroups identified were autumnalis (including a new serovar bim), icterohaemorrhagiae, ballum and canicola. The majority of patients presented with jaundice (95%,) anorexia and headaches (85%), fever (76%) and conjunctival suffusion (54%). While abnormal creatinine levels were seen in 49% of patients on admission, only 16% were judged to have had renal failure. The urine to plasma urea ratio showed high sensitivity and specificity in the diagnosis of pre-renal azotemia. Cardiac arrhythmias and myocarditis occurred in 18% of patients and pericarditis in 6%. An elevated serum amylase was found in 65% of cases. The bilirubin level took 5.5 weeks to return to normal. Thrombocytopenia was shown not to be due to a disseminated intravascular coagulation, and a randomised trial of high dose penicillin did not reveal any benefit to jaundiced patients. The overall mortality during the study was 5.7%.

Urinary diagnostic indices in the management of leptospirosis. Selection of patients for dialysis therapy.

Cases of leptospirosis admitted to the Queen Elizabeth Hospital (QEH), Barbados, were assessed for the presence of "pre-renal azotaemia" (NON-ARF) as opposed to "acute renal failure" (ARF). Distinction between the two diagnoses was made on the basis of clinical course. Peritoneal dialysis was inappropriately utilised in 26% of patients receiving such therapy. This study evaluates diagnostic tests for pre-renal azotaemia, and acute renal failure in leptospirosis, and indicates guidelines for the management of azotaemia in such patients. U/P urea and osmolar ratios show high sensitivity and specificity in diagnosing pre-renal azotaemia. While "early" dialysis is essential for patients with acute leptospiral renal failure, in those with plasma creatinines less than 600 mumol/litre on entry and indices indicating NON-ARF, decisions regarding dialysis can safely be delayed for 48-72 hours while the effect of rehydration is assessed.

Urinary diagnostic indices in the management of leptospirosis: selection of patients for dialysis therapy

Cases of leptospirosis admitted to the Queen Elizabeth Hospital (QEH), Barbado, were assessed for the presence of "pre-renal azotaemia" (NON-ARF) as opposed to "acute renal failure" (ARF). Distinction between the two diagnoses was made on the basis of clinical course. Peritoneal dialysis was inappropriately utilised in 26% of patients receiving such therapy. This study evaluates diagnóstic tests for pre-renal azotaemia, and acute renal failure in leptospsirosis, and indicates guidelines for the management of azotaemia in such patientes. U/P urea and osmolar ratios show high sensitivity in diagnosing pre-renal azotaemia. While "early" dialysis is essential for patients with acute leptospiral renal failure, in those with plasma creatinines less than 600 micronmol/litre on entry and indices indicating NON-ARF, decisions regarding dialysis con safely be delayed for 48-72 hours while the effect of rehydration is assessed

Penicillin therapy in icteric leptospirosis.

A prospective, controlled randomized study of penicillin therapy in icteric human leptospirosis was carried out between 1 October 1983 and 31 December 1986. Thirty-eight patients received intravenous crystalline penicillin for 5 days, while 41 assigned to a control group received intravenous fluids only. A comparison of the results of laboratory tests made on the day of admission revealed no significant differences between the 2 groups. There was no significant difference in time for defervescence, return of biochemical parameters to normal, incidence of iritis, or mortality in the 2 groups. Three patients (7.3%) in the control group and 1 patient (2.6%) in the treatment group died. The overall mortality rate was 5.9%. Leptospira were recovered from urine cultures in 6 control patients but from none of the treated patients' post-treatment cultures. We conclude that penicillin has little effect on clinical outcome in icteric leptospirosis.

Thrombocytopenia in leptospirosis: the absence of evidence for disseminated intravascular coagulation.

In a prospective study of human leptospirosis, thrombocytopenia was demonstrated in 54% of 24 cases. The only additional laboratory evidence suggestive of disseminated intravascular coagulation lay in a mild elevation of fibrinogen degradation products, but this occurred with equal frequency in nonthrombocytopenic patients. There is therefore no causal relationship between disseminated intravascular coagulation and the thrombocytopenia of human leptospirosis.

The management of severe hypertension with minoxidil in a once-a-day treatment regimen.

We evaluated the antihypertensive efficacy of "once-a-day" minoxidil, given in conjunction with a diuretic and sympatholytic, and the effect of this simple regimen on patient compliance. Twenty-one severely hypertensive patients had their existing antihypertensive regimens changed to a single daily dose of chlorthalidone (50-100 mg) and either nadolol (160 mg) or reserpine (.25 mg) for a 3-week period. After stabilization on these two drugs, a single daily dose of minoxidil (2.5 mg) was added to each patient's regimen. Doses were titrated as necessary to achieve diastolic blood pressures of less than 90 mmHg. After 3 and 6 months of maintenance therapy, blood pressures were measured 24 hours after the previous day's dosing to evaluate the persistence of the antihypertensive effect. Twenty-four-hour blood pressure control was achieved on 76% of these occasions, and on at least one occasion in 90% of the patients. In addition, compliance was excellent.

Rheumatic fever prophylaxis: a three-year study.

An effective programme of secondary prophylaxis against rheumatic fever has been established in Barbados over the last three years. Relatively unsophisticated patients collaborated well over prolonged periods. Adequate secondary prophylaxis was achieved with monthly injections of benzathine penicillin, with a resultant decrease in the complication rate.A total of 84 admissions over 32 months from a population of some 60,000 children under the age of 12 emphasizes the need for registration and prophylactic treatment of children with rheumatic fever. The low yield in the survey of schoolchildren between the ages of 5 and 11 and the large number of personnel required for the survey suggest that it might be extended to include older age groups. Automatic screening devices should be used when possible so that more may be screened.

Rheumatic fever and rheumatic heart disease in Barbados: detection and prophylaxis.

The objectives of this study were to improve our methods of secondary prophylaxis of rheumatic fever and rheumatic heart disease in Barbados, to estimate the overall prevalence of these diseases and the relative load imposed by them on available health services, and to measure the yield, feasibility, and effectiveness of mass programmes for the detection and prophylactic management of rheumatic heart disease in schoolchildren.Improved methods of surveillance and follow-up resulted in 97% adherence to therapy by patients on prophylactic penicillin. Thirty-four children, 27 with a first attack, were admitted with acute rheumatic fever, representing a 7% occupancy of children's medical beds during the 12-month period of the study. Out of a possible 3,942 schoolchildren aged 5-11 years, 3,882 (98%) were screened for rheumatic heart disease. Four cases (about 1 per 1,000) were discovered.