Direct detection of leptospiral material in human postmortem samples.

Leptospiral culture, direct immunofluorescence, and the polymerase chain reaction (PCR) were used to detect leptospiral material in postmortem specimens collected from eight patients who died of leptospirosis. Diagnosis of leptospiral infection was based on clinical summary (premortem) and confirmed by serological analysis and/or culture of leptospires. Leptospiral culture was the least sensitive technique, yielding two isolates (3%) from 65 samples. Both isolates were from the aqueous humour and cerebrospinal fluid of the same patient. Direct immunofluorescence was of intermediate sensitivity for detection of leptospires, confirming the presence of leptospires in 11% (2 of 18) of tissue samples from three patients. PCR analysis was the most sensitive technique for detection of leptospiral material in tissue samples, being positive in 20% (11 of 56) of samples from eight patients. Both samples (cerebellum and liver) positive by immunofluorescence were also positive by PCR. The sensitivity of the PCR assay was 1-10 leptospires ml(-1) sample, and the assay was specific for Leptospira pathogenic species. Multi-system involvement was indicated based on successful amplification of leptospiral DNA from more than one tissue sample, which corroborated with the clinical and pathologic findings. The results suggest that in acute and/or fatal leptospirosis, the pathogenesis of the pathologic features are related to the presence of the organisms in the tissues. In conclusion, PCR combined with serology appears to be a useful tool for diagnosis of leptospirosis and may be invaluable in epidemiological studies.

Simple method for production of internal control DNA for polymerase chain reaction assays for leptospira spp. - abstract

A simple and highly versatile one-step method for the production of internal control DNA for an established polymerase chain reaction assay for Leptospira interrogans is described. The internal control was produced from DNA of serovar bim, and is amplified with the same primers used routinely in our PCR assays. The inclusion of the internal control in the reaction mixture did not affect the efficacy of amplification of the target DNA. The method is simple and rapid and should be adaptable to most PCR assays for Leptospira spp. (AU)

Use of the polymerase chain reaction for rapid diagnosis of leptospirosis - abstract

Leptospirosis is endemic in Barbados with 97 percent of severe cases caused by three serovars of leptospira interrogans. Early diagnosis is important since the disease can run a fulminant course and patients may die before the appearance of characteristic clinical manifestations of Leptospirosis and/or leptospiral antibodies are detected, and therefore the disease may go unrecognized. In this study, the potential of the polymerase chain reaction (PCR) was explored for the early diagnosis of leptospirosis, with a view to detecting leptospirosis within the first ten days of the onset of the disease. Blood and urine samples from 83 patients with leptospirosis admitted to the Queen Elizabeth Hospital, Barbados, between January 1990 and December 1992, were examined serologically, by culture and by PCR. The mortality rate during the study period was 8.4 percent. PCR was more often positive than culture for the detection of leptospires in proven cases by antibody titre and detected the presence of leptospires in sera before the development of antibodies. As culture can take up to 13 weeks, it does not contribute to an early diagnosis. Seroconversion usually occurs on about the seventh day of the disease, thus diagnosis by serology can take a week or more to be decisive. PCR, on the day of admission, and the characterization of PCR products by Southern hybridization can be completed within one or two subsequent days. PCR is potentially a valuable addition to the diagnostic process in leptospirosis (AU)

Leptospires isolated from toads and frogs on the island of Barbados

Four pathogenic strains of leptospires were isolated from the kidneys of toads (Bufo marinus) and seven from frogs (Eleutherodactylus johnstonei). Isolates from two toads and one frog belonged to serovar bim, the causative agent of most cases of severe leptospirosis on Barbados. The other eight strains belonged to a new serovar within the Australis serogroup. The name bajan is proposed for this new serovar of Leptospira interrogans. (AU)

Retention of leptospiral agglutinins and long-term response to administration of monoclonal antibodies in vervet monkeys (Cercopithecus aethiops) on Barbados

In a study of 21 wild-caught Barbadian vervet monkeys (Cercopithecus aethiops sabaeus), naturally-acquired leptospiral agglutinins were found to persist for over five years. Groups of seropositive as well as seronegative vervets were given a placebo, or full-strength monoclonal antibodies MCA F12C3 (Icterohaemorrhagiae copenhageni), or diluted F12C3 MCAs. They were challenged 24 hours later with a suspension of highly virulent leptospires (copenhageni) administered intraperitoneally. Immunoprotection was evident in animals receiving full strength MCAs as measured by their failure to develop any sunstantial antibody response and by their lower geometric mean titres over a period of 142 weeks (maximum GMT of 113 compared with a maximum of 1280 in the placebo group). Diluted MCAs had little or no protective value. The serological response of the monkeys which were seropositive at capture to challenge with virulent copenhageni antigen was strongly anamnestic both in those given MCAs and those given placebo. None of the naturally or experimentally infected vervets showed clinical signs of leptospiral illness. (AU)

Intestinal parasites in Amerindians of the interior of Surinam

Describes 3 cross-sectional studies of intestinal parasites among groups of Amerindians in the densely forested interior of Surinam. During the first study (1965) 430 stool samples were examined, during the second study (1967) 289 and during the third study (1970) 414. The subjects of those studies still live isolated. This study proved that man's Isospora hominis and dog's Isospora hominis-like sporocysts are not identical. The study aimed at the detection of as many parasite species as possible. It demonstrated 18 varieties of parasites, of which Enteromonas hominis proved to be the most prevalent parasite. Low prevalences were observed for Dientamoeba, Retortamonas, Isospora belli and Balantidium. In 1970 156 sera were tested with the agar gel diffusion test for antibodies against Entamoeba histolytica. The over-all prevalence of positive sera was 13 per cent. Several techniques were also tested for their usefulness in fieldwork