EPIDEMIOLOGICAL AND BACTERIOLOGICAL STUDIES ON ANIMAL AND HUMAN LEPTOSPIROSIS IN PLATEAU STATE, NIGERIA.
EPIDEMIOLOGICAL AND BACTERIOLOGICAL STUDIES ON ANIMAL AND HUMAN LEPTOSPIROSIS IN PLATEAU STATE, NIGERIA.
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Date
1988-12
Authors
EZEH, ANTHONY OKAY
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Abstract
ABSTRACT
Leptospirosis is an infectious and contagious disease of animals and man caused by spiral-shaped organisms belonging to the genus Leptospira. Although it is known that eptospirosis is prevalent in the tropical and
subtropical areas of the world, few studies on the disease have been reported in Nigeria. The present study was designed to determine the prevalence rate of leptospiral antibodies in voluntary blood donors and cattle in the 14
local government areas of Plateau State; to attempt isolation of leptospires from bovine and rodent kidneys; to characterize all such isolates and determine their pathogenicity through experimental studies. Leptospiral antibody titre of 1:100 or more was detected in 14.4 per cent of 1,537 cattle screened in the 14 local government areas of Plateau State using 13 live serovars in a modified microscopic agglutination test. Of the 222 animals that were sero-positive, antibodies to serovar hardjo was the most prevalent accounting for 35.6 per cent. The serological prevalence rates of bovine leptospirosis ranging from 7.9 per cent to 28.0 per cent in the different local government areas differed significantly (P < 0.05; X2). Six leptospiral strains belonging to Sejroe and Pyrogenes serogroups were isolated from 525 bovine kidneys examined bacteriologically. In a similar examination of 502 rodents, no leptospire was isolated but 44.9 per cent of 105 trapped rodents tested were serologically positive.
In a serological examination of serum samples obtained from 710 voluntary blood donors in the study area 18.0 per cent were positive for leptospirosis. Of the 123 sero-positive individuals, serovar hard jo was the most common with a prevalence rate of 21.9 per cent. There was no statistical significant difference in the prevalence
rate of leptospirosis in the different local government 2 areas (P>0.05; X ). Abattoir workers with a prevalence rate of 29.5 per cent were occupationally at risk of contracting leptospirosis and about 39.0 per cent of all pyrexic patients examined were serologically positive. A variant strain of Hardjoprajitno was isolated from the mid-stream urine of an abattoir worker.
Cross-agglufcinin absorption tests showed that five of the bovine isolates were identical and they belonged to Pyrogenes serogroup. The sixth bovine and the only human isolates were similarly identified as serovar hard jo, genotypes hardjobovis and hardjoprajitno respectively. The isolation of these two hardjo genotypes is being documented for the first time in Nigeria and all the six bovine isolates exhibited boiological properties consistent with pathogenic leptospires. The restriction endonuclease analysis patterns showed the uniqueness of the human isolate in having an extra band. Also, the restriction patterns of the bovine isolates were different from those of other reference serovars in the Pyrogenes serogroup.
Description
THESIS Submitted to AHMADU BELLO UNIVERSITY
For the degree DOCTOR OF PHILOSOPHY
Department of Veterinary Pathology and Microbiology Faculty of Veterinary Medicine DECEMBER 1988
Keywords
EPIDEMIOLOGICAL,, BACTERIOLOGICAL,, ANIMAL,, HUMAN LEPTOSPIROSIS,, PLATEAU STATE,, NIGERIA.