Serological and bacteriological study of leptospirosis in dairy herds and feedlot in Tehran suburbs

Authors

1 Department of Internal Medicine, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

2 Department of Hygiene and Food control, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

Abstract

BACKGROUND: Leptospirosis is a worldwide zoonosis caused
by Leptospira interrogans. Leptospirosis results in decreased
milk production, abortion, stillbirth, infertility and mortality,
which causes financial loss in the cattle industry. OBJECTIVES:
The aim of this research was to perform a serological and
bacteriological study of leptospirosis in 6 industrial dairy herds
and 3 feedlots with previous records of leptospirosis in Tehran
suburbs in 2011-2012. METHODS: For the purpose of this study,
408 blood samples from dairy cattle and 154 blood samples from
feedlots were collected using sterile 10ml venoject vacutainers
from tail vein. Two months later, 118 urine samples were
collected from 20% of the two groups of serological negative and
positive animals. All serum samples were serologically tested by
microscopic agglutination test (MAT), a standard method for
serological diagnosis of leptospirosis. The serum samples were
tested for antibodies against five live antigens of Leptospira
interrogans serovars: Pomona, Grippotyphosa, Hardjo, Icterohaemorrhagiae
and Canicola. Urine samples were used for
bacteriological isolation of Leptospira spp. RESULTS: Serological
results showed that 228 (40.6%) of animals had a positive
reaction against one or more serovars. The most prevalent
Leptospira serovars was Pomona 118 (40.3%) and the least
prevalent was Canicola 4 (1.4%). The most prevalent titer was
1:100, and the highest titer was 1:1600. Also the most
seropositive cases were observed in 3 to 4-year-old cows.
Bacteriological results revealed that in 11 (9.3%) urine samples
Leptospira spp. were isolated, all taken from one feedlot farm.
According to the history taken from each farm, the main risk
factors were the presence of rodents and low hygienic conditions
of the farms. CONCLUSIONS: The results of this study revealed
that cows could have a major role in maintaining Pomona,
Grippotyphosa and Hardjo serovars; indeed, they are a potential
zoonotic risk to slaughter house workers, meat inspectors,
milkers and farmers.

Keywords

Iranian Journal of Veterinary Medicine
Volume 7, Issue 3 - Serial Number 3
October 2013
Pages 177-183

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