Leptospira in slaughtered fattening pigs in southern Vietnam: presence of the bacteria in the kidneys and association with morphological findings.
ABSTRACT One kidney was collected from each of 32 fattening pigs at an abattoir in southern Vietnam in 2001 in order to demonstrate infecting Leptospira serovar and to associate renal macro- and microscopic findings with the presence of renal leptospires. Leptospires were demonstrated in 22 (69%) of the investigated kidneys by immunofluorescence. Multifocal interstitial nephritis (MFIN) and gross renal lesions (white spots) were each demonstrated in 24 (75%) kidneys. Leptospira interrogans serovar bratislava was isolated from one kidney. There was no association between presence of leptospires and MFIN (P=0.19), respectively and white spots (P=0.98), respectively. These data suggest that Leptospira infection is common among fattening pigs in the study area and that these animals may be considered as an occupational human health hazard. It is also suggested that the presence of white spots is an unreliable indicator of the presence of renal leptospires.
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ABSTRACT: Leptospirosis is a systemic disease affecting humans and animals, and pigs are generally considered the reservoir host species for the serovars Pomona, Bratislava and Tarrasovi. Endemic infections in swine herds generally remain subclinical, as do the vast majority of leptospire infections. However, when a susceptible breeding herd is infected for the first time or its immunity is compromised, considerable losses can occur due to abortion, stillbirths, weakly piglets or infertility. Infections in pigs caused by other serovars tend to occur only incidentally, vary regionally, and depend on other reservoir hosts, primarily rodents. Leptospires persist in porcine kidneys, and the Bratislava serovar, in the genital tract; it is excreted in urine and genital fluids. Leptospirosis is transmitted by direct or indirect contact with an infected animal. Fundamental research on porcine leptospirosis was conducted in the 1970s and 1980s. However, despite subsequent application of the most recent molecular biological methods, the pathogenesis of porcine leptospirosis is still largely unknown, and research results from the last 25 years on its incidence are very heterogeneous, due not only to regional differences but also to differences in the evaluation of diagnostic and population studies. Serological testing of pigs showed serovar prevalences ranging between as much as 16.3% (Pomona) and generally no more than 2.9% (Tarassovi), whereas antibodies against Bratislava were found in as many as 41.8% of pigs tested during the last 20 years, as in previous studies, indicating that this remains the most prevalent serovar.Berliner und Münchener tierärztliche Wochenschrift 01/2011; 124(9-10):345-59. · 0.89 Impact Factor
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ABSTRACT: Leptospirosis is the most widespread zoonosis in the world. Humans become infected through contact with the urine of carrier animals, directly or via contaminated environments. This review reports available data on animal leptospirosis in ten tropical islands: Barbados, Martinique, Guadeloupe, Grenada, Trinidad, New Caledonia, Hawaii, French Polynesia, La Réunion and Mayotte. Leptospirosis is endemic in these insular wild and domestic fauna. Each island presents a specific panel of circulating serovars, closely linked with animal and environmental biodiversity, making it epidemiologically different from the mainland. Rats, mongooses and mice are proven major renal carriers of leptospires in these areas but dogs also constitute a significant potential reservoir. In some islands seroprevalence of leptospirosis in animals evolves with time, inducing changes in the epidemiology of the human disease. Consequently more investigations on animal leptospirosis in these ecosystems and use of molecular tools are essential for prevention and control of the human disease.Epidemiology and Infection 02/2011; 139(2):167-88. · 2.87 Impact Factor
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ABSTRACT: AIM: To determine the association between white-spot lesions in kidneys and serological and cultural prevalence of leptospirosis in sheep, and to evaluate the diagnostic value of these lesions in individual sheep and lines of sheep at slaughter as indicators of past or current episodes of leptospirosis. METHODS: Lines of lambs were randomly selected, and within lines individual lambs were randomly selected at slaughter. Blood samples and entire kidneys were collected. Serum was tested using the microscopic agglutination test (MAT) for antibody against Leptospira borgpetersenii serovar Hardjobovis or Leptospira interrogans serovar Pomona. Kidneys were cultured for the presence of Leptospira spp. The association between grossly visible white-spotted kidneys (WSK) and the serological status, and between WSK and culture status was evaluated at both line and individual levels. A fixed-effect multivariable logistic regression model was fitted to the line-level data, and included within-line prevalence of carcasses with WSK and line size. A random-effect multivariable logistic regression model was fitted to the individual-level data. This model included WSK lesion score and a random line effect. RESULTS: White-spot lesions in kidneys were significantly associated with the serological status for Leptospira spp. in individual sheep. A strong positive dose-response relationship between sero-status and the number of white spots on kidneys was observed. However, the sensitivity of WSK to detect seropositive carcasses was low (51 (95% CI=43-59)%), and specificity was moderately low (86 (95% CI=84-87)%). Due to a low observed seroprevalence of 5.2 (95% CI=3.9-7.1)% to serovar Hardjo or Pomona, the positive predictive value (PPV) of WSK for serology was only 18 (95% CI=14-22)%, and the negative predictive value (NPV) was 96 (95% CI=96-97)%. Carcasses with high WSK lesion scores (more than five white spots or white mottling on one or both kidneys) were 6.1 (95% CI=4.3-8.3) times more likely to be seropositive to either serovar than were carcasses with low scores (one to five white spots on one or both kidneys). However, the test sensitivity and PPV for these criteria were regarded unacceptably low (27 (95% CI=20-34)% and 27 (95% CI=21-35)%, respectively). Consideration of lesion status of lines rather than individual animals resulted in a high sensitivity of 98 (95% CI=87-100)%, but very low specificity of 15 (95% CI=8-27)% and a PPV of 48 (95% CI=37-59)%. Due to the low sensitivity of WSK and low prevalence of culture- positive carcasses, the PPV for WSK was as low as 4 (95% CI=2-12)%. CONCLUSIONS: Whereas highly significant associations, including a strong dose-response effect, were observed between WSK and MAT serology, WSK was a poor predictor for the antibody and pathogen status of sheep carcasses with respect to leptospirosis.New Zealand veterinary journal 03/2009; 57(1):28-33. · 1.06 Impact Factor