SEROEPIDEMIOLOGY AND MOLECULAR CHARACTERIZATION OF LEPTOSPIROSIS IN ANDHRA PRADESH
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Date
2010-11
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Sri Venkateswara Veterinary University, TIRUPATI – 517 502,A.P
Abstract
ABSTRACT:
Leptospirosis the world wide zoonosis is considered as reemerging
disease. Besides economic losses caused by leptospira to
animal production, its zoonotic character makes it an important public
health problem. Due to the endemicity of the disease in Tamil Nadu,
Kerala and Karnataka the adjoining states of Andhra Pradesh and
absence of detailed information on leptospirosis in the state, the present
work was planed to study seroepidemiology, isolation, characterization of
leptospira and development of inactivated adjuvanted vaccine and to
asses immune response in rabbits.
The seroepidemiological study conducted using MAT on 2320
serum samples collected from apparently healthy cattle, sheep, goat, dogs
and pigs revealed 20.9 percent positivity. Similarly 33.37 percent
positivity was recorded from clinically suspected cases of cattle, sheep,
pigs, dogs and humans. High seroprevalence in coastal region (23.09
percent) followed by Rayalaseema (17.49 percent) and Telangana (16.30
percent) was observed.. High seropositivity was recorded during north
east monsoon (28.29 percent) followed by south west monsoon (21.45
percent) and lowest in summer (7.26 percent). Biochemical analysis of
serum samples from cattle positive for MAT showed elevated levels of
total bilirubin, SGPT and SGOT.
Clinical samples collected from cattle (26) sheep (42) dogs (13),
Pigs (15), Humans (53), and stagnated water in rice fields (10) were
inoculated in EMJH Liquid medium with tween 80, antibiotics and 5-
Flurouracil. A total of 17 isolates were recovered from sheep (5), rat (5),
pigs (4), Humans (2) and rice field (1) were purified and maintained in
EMJH liquid medium and semi solid medium.
Physiochemical characterization of isolates at 130C, growth in the
presence of 8-Azaguanine and lipase activity revealed the pathogencity
of the isolates. PCR detected 12 isolates, of 17 isolates tested. RAPD
DNA analysis was found to be simple and rapid test for identifying
serovars of leptospira. The test identified the leptopsiral isolates as L.
hardjo, L. autumnalis and L.pomona. 16S rRNA PCR sequence analysis
of leptospiral isolates recovered from sheep were identified as Leptonema
illini, L. hardjo and L.inadai, from rats were identified as Leptonema
illini, L. noghuchi and from pigs identified as L. Pomona.
A trivalent inactivated vaccine was prepared with three commonly
circulating serovars namely L. grippotyposa, L. hardjo and L. autumnalis.
The vaccine was adjuvanted with alumminium hydroxide (Vaccine-I) and
Montanide (Vaccine-II) and the immune response in rabbits was studied.
There is no significant difference between the vaccines. Both the
adjuvanted vaccines yielded satisfactory immune response up to 150 days
post vaccination.