Citation
Bejo, Siti Khairani
(2001)
Epidemiology of Leptospirainterrogans Serovar Hardjo Infection in Cattle.
Doctoral thesis, Universiti Putra Malaysia.
Abstract
The serological prevalence of Leptospira interrogans serovar hardjo
(hereafter referred to serovar hardjo) infection in cattle in this present study was
30%. Water samples from stagnant water, pond water, tank water and drain
water collected from the farms were positive to Leptospira biflexa (40%) . Twentyfour
per cent of soil samples obtained from three different types of soil namely
clay, loam and sand in the farms were also positive to Leptospira biflexa.
However, serovar hardjo or other pathogenic leptospires were not isolated in the
urine, soil and water samples collected in the farms. Clinical sign of leptospiral
infection was not observed in the cattle on the farms. The leptospiral isolates
were further characterized using bacterial restriction endonuclease DNA
analysis (BRENDA), polyacrylamide gel electrophoresis (PAGE) and Western
blotting. It was confirmed that the leptospiral isolates did not belong to serovar
hardjo.Under experimental condition it was demonstrated that cattle are able to
maintain serovar hardjo. Six female 8-months-old Kedah-Kelantan calves were
used in this trial. Leptospiremia occurred as early as 7 days post-inoculation and
lasted for 13 days following intra-conjunctival inoculation. Antibody against
serovar lzardjo was first detected at day 7 post inoculation, then raised to a high
level at day 14 post-inoculation and maintained at the same level up to 365 days
post inoculation. Leptospiruria was first detected on day 49 post inoculation and
maintained up to day 147 post-inoculation. Histologically serovar hardjo was
detected in the renal tubule at the end of the trial using immunoperoxidase
staining. No clinical signs of leptospiral infection was observed in the same
animals throughout the trial. Identification of the leptospiral isolates obtained
from the inoculum and urine samples of the experimental animals using
bacterial restriction endonuclease DNA analysis (BRENDA) and polymerase
chain reaction (peR) showed that both isolates were serovar hardjo.
The study showed that serovar hardjo can survive in rain water up to 264
hours (11 days) under experimental condition. Leptospira interrogans serovar
hardjo can survive up to 72 hours (3days) in diluted urine in Malaysian field
condition and up to 984 hours (41 days) at 4°C. Leptospira interrogans serovar
hardjo can survive in chlorinated drinking water up to 120 hours (5 days) but
was killed immediately in seawater. The organism can survive in soil samples up to 144 hours (6 days) . The contaminated environment with serovar 11l1rdjo can
transmit infection of the organism to susceptible animals.
It is evident that serovar hardjo infection is present in cattle farms in
Malaysia. Cattle in Malaysia have a potential of maintaining serovar hardjo.
Leptospira interrogans serovar hardjo has been shown to survive in water and soil
for a long time in Malaysian field condition and the organisms can be
transmitted to susceptible animals.
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