Maximizing the chances of detecting pathogenic leptospires in mammals: The evaluation of field samples and a multi-sample-per-mammal, multi-test approach

Tulsiani, S. M., Graham, G. C., Dohnt, M. F., Burns, M. -A. and Craig, S. B. (2011) Maximizing the chances of detecting pathogenic leptospires in mammals: The evaluation of field samples and a multi-sample-per-mammal, multi-test approach. Annals of Tropical Medicine and Parasitology, 105 2: 145-162. doi:10.1179/136485911X12899838683205


Author Tulsiani, S. M.
Graham, G. C.
Dohnt, M. F.
Burns, M. -A.
Craig, S. B.
Title Maximizing the chances of detecting pathogenic leptospires in mammals: The evaluation of field samples and a multi-sample-per-mammal, multi-test approach
Journal name Annals of Tropical Medicine and Parasitology   Check publisher's open access policy
ISSN 0003-4983
1364-8594
Publication date 2011-03
Sub-type Article (original research)
DOI 10.1179/136485911X12899838683205
Volume 105
Issue 2
Start page 145
End page 162
Total pages 18
Place of publication London, England
Publisher Maney Publishing
Collection year 2012
Language eng
Formatted abstract
Identification of wild animals that harbour the causative leptospires, and the identification of the most important of these ‘wild reservoirs’ (in terms of threat to human health), are key factors in the epidemiology of human leptospirosis. In an epidemiological investigation in the Australian state of Queensland, in 2007–2008, samples were collected from fruit bats (Pteropus conspicillatus) and rodents (to investigate the potential role of fruit bats in the maintenance and transmission of leptospires to ground-dwelling rodents) and checked for pathogenic leptospires.
The results of these studies have now been carefully analysed in attempts to see which method of detection and type of test sample were best. The effects of pentobarbitone sodium used to euthanize wild mammals before collection
of necropsy samples, on the survival and detection of leptospires in vitro, were also explored. In the earlier field investigation, serum, renal tissue and urine were collected from wild mammals, for the detection of pathogenic leptospires by culture, the microscopic agglutination test (MAT), real-time PCR and silver impregnation of smears. Although 27.6% of the rodents investigated were found leptospire-positive, culture only yielded four isolates, probably because many cultures were contaminated. The main aims of the present study were to quantify the performance of the individual diagnostic tests and examine the reasons behind the high incidence of
culture contamination.  The results of sensitivity and specificity analyses for the different diagnostic tests indicated that isolation by culture (the definitive diagnostic test for leptospiral shedding) had perfect (100%) sensitivity when compared with
the results of the PCR but a low specificity (40%). The MAT performed poorly, with a sensitivity of 50% when compared against the results of culture. The prevalence of leptospiral carriage revealed by the PCR-based investigation of kidney and urine samples (59.2%) was higher than that revealed using any other method and far
higher than the 2.0% revealed by culture. The results of the culture of renal tissue agreed fairly well with those of the PCR-based investigation of such tissue, with a Cohen’s unweighted kappa coefficient (k) of 0.5 (P50.04). The levels of agreement between other pairs of tests were generally poor.
Keyword Pentobarbital
Aggluination test
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Veterinary Science Publications
 
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Created: Wed, 09 Feb 2011, 09:34:33 EST by Suhella Tulsiani on behalf of School of Veterinary Science