The mongoose as a reservoir of leptospirosis - abstract

ABSTRACT

This paper presents the data on the incidence of leptospirosis in the Southern Caribbean and gives special emphasis to the mongoose which is a known carrier of the disease. Leptospira isolates from blood in man and blood and kidney tissue in animals have been maintained in tryptose phosphate broth cultures. Serological studies have been undertaken by both complement fixation (CF) and microscopic agglutination (MA) tests. Reports from United States indicate that only 20 percent of human leptospirosis cases are immediately recognized; common diagnoses include meningitis, hepatitis, nephritis, fever of unknown origin, and influenza (Busch, 1970). Symptoms are inconsistent, with the classical clinical jaundice of Weil's disease being reported in less than 50 percent of cases. In the eleven years 1961 - 1971, there was an average of 81.7 reported cases of leptospirosis per year in the United States. The annual average for Barbados was 14.2 taken over the past five years, and for Jamaica 9.8 taken over the past six years. Trinidad has reported only an average of 0.8 cases per year in the last five years, while Grenada does not report leptospirosis at all. Our studies indicate that the infection is common in mongooses in Grenadam with high anti-body titres (< 100 by MA test) in 35.2 percent in (152 of 432) animals examined. Serologic studies indicate three serogroups are present Icterohaemorrhagiae (36.8 percent), Pomona (21.0 percent), and Canicola (6.6 percent). The remaining 35.6 percent positive samples suggest a history of mixed infections with icterohaemorrhagiae predoninating. In Trinidad, the proportion is higher, with 51.1 percent (24 of 41) mongooses positive; serotype canicola predominates, and this is confirmed by leptospiral isolates from kidney tissue. Between 1968 and 1971, blood cultures from 694 clinical patients in Trinidad gave five leptospira isolates; and, in addition, CG antibodies were detected in 5.1 percent ( 48 of 934) of human survey sera. Including earlier studies, a total of eight serotypes, two of them new sub-serotypes, have been recorded from six serogroups. Although infected water, domestic animals, and periodomestic rodents are usually considered to be the sources of human leptospirosis the high prevalence of infection in mongooses, coupled with their behaviour and distribution suggests that they may play an important role in the epidemiology of the disease; and this has hitherto been insufficiently emphasized in the Caribbean (AU)