Surveillance of leptospiral carriage by feral rats in Barbados

Rodents, particularly rats, are widely held to be the source of most human cases of leptospirosis. Feral rats were trapped at sites throughout Barbados during two six month surveys: from October to March 1986/87 and from October to March 1994/95. During the first survey, 63 rats were trapped, of which 26 (41) were identified as Rattus rattus and 37 (59) as Rattus norvegicus. In the second study, 100 rats were trapped, of which R. rattus comprised 24(24) and R. norvegicus 76(76). Cultures of blood, urine and kidney were made in EMJH medium. Leptospires were isolated from 12/63 (19) and from 16/100 (16) of the rats during 1986/87 and 1994/95, respectively; 27/28 isolates were recovered from the kidneys or urine or both, while only one isolate was recovered from the blood. During the first study, isolates were identified as serovars copenhageni (11) and arborea (1), while in the second study, serovars copenhageni (9), arborea (5) and bim (1) were identified; one isolate was lost before it could be identified. In the first study, antibodies were detected by microscopic agglutination at a titre of > or = 100 in 26/62 (42) of rats tested, while in the second survey, 5/100 (5) of rats had similar titres. In two surveys, conducted eight years apart, we confirmed that rats in Barbados are commonly infected with leptospires, and that viable organisms are found in the kidneys and urine, evidence of chronic infection and thus excretion of leptospires in rodent urine. Moreover, the predominant serovar isolated was copenhageni, of which Rattus spp. are the worldwide reservoir. There was little evidence that rats act as a reservoir for the serovar bim, the most common cause of human leptospirosis in Barbados.

Leptospirosis in Madras--a clinical and serological study.

Leptospirosis was confirmed by Microscopic Agglutination Test (MAT) and/or ELISA in 57 patients admitted to the Government General Hospital, Madras, India, during November and December of 1990 and 1991 with symptomatology suggestive of the disease. Fifty (88%) of the 57 cases were males; the mean age of all the cases was 39.6 years (range 17-72). The main clinical features were: fever 100% jaundice 84%, Myalgia 82%, acute renal failure 72% and conjunctival suffusion 58%. Non-azotemic jaundice occurred in 19% of cases. Renal failure was non-oliguric in 24% of cases. 3.5% of patients died. 23 patients underwent peritoneal and/or hemodialysis. ELISA IgM titres ranged from 1:80 to 1:10240 (geometric mean tire 911). MAT titres > or = 1:1600 and > or = 1:800 occurred in 39 of 54 and 51 of 54 cases respectively. Autumnalis was the serogroup most commonly recorded serologically, and Leptospira interrogans serovar autumnalis was isolated from one patient. This study shows that leptospirosis is a significant health problem in Madras, though normally grossly underestimated due to the absence of routine laboratory diagnostic facilities for the disease. Gross under-reporting is also likely in other high rainfall third world areas.

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), 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