ABSTRACT
The main goal of this study was to evaluate the prevalence of leptospirosis among field rodents of Tiruchirappalli district, Tamil Nadu, India. In total 35 field rats were trapped and tested for seroprevalence by the microscopic agglutination test (MAT). Isolation of leptospires was performed from blood and kidney tissues and characterized to serovar level. Genomospecies identification was carried out using 16S rRNA and lipL32 gene sequencing. The molecular phylogeny was constructed to find out species segregation. Seroprevalence was about 51.4 percent, and the predominant serovars were Autumnalis, Javanica, Icterohaemorrhagiae and Pomona. Two isolates from the kidneys were identified as serovar Javanica of Serogroup Javanica, and sequence based molecular phylogeny indicated these two isolates were Leptospira borgpetersenii.
Subject(s)
Animals , Rats , Base Sequence , Leptospirosis , Leptospira interrogans serovar autumnalis/isolation & purification , Leptospira interrogans serovar icterohaemorrhagiae/isolation & purification , Leptospira interrogans serovar pomona/isolation & purification , Phylogeny , Agglutination Tests , Methods , Prevalence , Seroepidemiologic Studies , SerotypingABSTRACT
The main goal of this study was to evaluate the prevalence of leptospirosis among field rodents of Tiruchirappalli district, Tamil Nadu, India. In total 35 field rats were trapped and tested for seroprevalence by the microscopic agglutination test (MAT). Isolation of leptospires was performed from blood and kidney tissues and characterized to serovar level. Genomospecies identification was carried out using 16S rRNA and lipL32 gene sequencing. The molecular phylogeny was constructed to find out species segregation. Seroprevalence was about 51.4 %, and the predominant serovars were Autumnalis, Javanica, Icterohaemorrhagiae and Pomona. Two isolates from the kidneys were identified as serovar Javanica of Serogroup Javanica, and sequence based molecular phylogeny indicated these two isolates were Leptospira borgpetersenii.
ABSTRACT
The study describes the first attempt to record leptospirosis in Erode by isolation and serological tests such as the microscopic agglutination test and IgM-based enzyme-linked immunosorbent assay. Twenty-nine clinically suspected cases showing fever, headache, body ache associated with jaundice, decreased urine output, and conjunctival suffusion were included. The age of the patients ranged between 10-71 years and most of them were agricultural workers. Paired sera were possible among 12 cases. All the patients had fever and headache and other more common symptoms were myalgia and icterus. Leptospiral culture was positive in 7 (24.1%) patients. Out of 29 patients, 26 (89.7%) were diagnosed as having current leptospiral infection based on serology and isolation. The leptospiral isolates KSR 1-6 were further characterized by using randomly amplified polymorphic DNA fingerprinting shown genetic similarities with Leptospira interrogans spp. This study shows the presence of leptospirosis among the hospital cases of Erode and that this disease is a potential health hazard of agricultural workers in Cauvery basin.
Subject(s)
Leptospira/genetics , Leptospirosis/microbiology , Adolescent , Adult , Aged , Child , DNA Fingerprinting/methods , Female , Humans , India/epidemiology , Leptospira/isolation & purification , Leptospirosis/epidemiology , Male , Middle Aged , Phylogeny , Random Amplified Polymorphic DNA Technique , Seroepidemiologic StudiesABSTRACT
Leptospirosis is not commonly reported from the Salem district in central Tamil Nadu in India. In October 2000, a rice mill worker, who had fever and jaundice, tested positive in leptospiral IgM enzyme-linked immunosorbent assay (ELISA). Microbiological and serological investigations were performed on the patient, a sample population of the rice mill workers, and the animal and rodent populations living in the same premises. Leptospira was isolated from the patient about 2 weeks after the onset of symptoms when he had recovered from illness following a course of doxycycline. The isolate was serovar Icterohaemorrhagiae of serogroup Icterohaemorrhagiae. The patient also showed a fourfold rise in titers in microscopic agglutination test (MAT) and IgG ELISA. The rice mill workers had a seroprevalence rate of 68.3%, which was significantly higher than that among a control group consisting of persons engaged in other occupations. Serological studies conducted among cattle, dogs, cats, and rats showed seroprevalence rates of 52.9%, 50.0%, 66.6%, and 52.1%, respectively. Leptospires were isolated from two rats, but the isolates were lost during subculturing and could not be characterized. The most predominant serogroup identified by MAT was Autumnalis for rice mill workers and all animal populations. The other serogroups that reacted in MAT were Icterohaemorrhagiae, Australis, Grippotyphosa, and Patoc. Although Australis and Grippotyphosa showed agglutination in the case of human samples, none of the animals had detectable titers to these serogroups. The rice mills of Salem, having large rodent populations, various animals living in close proximity, a wet environment, and unprotected exposure of the workers to the environment, constitutes an ideal setting for transmission of leptospirosis and could be an epidemiological niche of leptospirosis.
