Seroprevalence and associated risk factors of leptospirosis in bovine dairy farms in Telangana state, India.

The current cross-sectional study aimed to determine the seroprevalence of Leptospira infection in bovine dairy farms in the Telangana state of India, as well as the associated risk factors, in order to implement effective preventive measures for disease control. A total of 469 blood samples were collected from 67 herds/farms in different areas, covering 20 administrative districts in the state. These samples consisted of 253 from cattle and 216 from buffaloes. Questionnaires were used to collect data on host and epidemiological factors. The collected sera were tested using the gold standard serological test, the Microscopic Agglutination Test (MAT), which employed a panel of 18 reference serovars for Leptospira exposure. The statistical analysis of epidemiological data was carried out to identify the risk factors associated with Leptospira exposure. The overall observed seroprevalence at the animal and farm levels was 41.4% and 77.6%, respectively. The most prevalent anti-leptospiral antibodies were observed against the serogroups Icterohaemorrhagiae (32.4%), Pomona (22.2%), Javanica (19.1%), Australis (17.0%), Bataviae (15.5%), Autumnalis (12.9%), Hebdomadis (12.9%), and others, in the total reacting samples. At the animal level, the significant risk factors associated with exposure to Leptospira species were breed (p = 0.03) and health status (p = 0.03). Furthermore, the multivariate statistical analysis of farm factors revealed that farm size (p = 0.05), presence of dogs (p = 0.04) and rodents (p = 0.01) on the farm, use of fodder from wet soils (p = 0.04), and proximity to water bodies (p = 0.04) were significantly associated with exposure to Leptospira in the studied region. This study provides the first report from India highlighting the important risk factors at the herd/farm and animal level associated with Leptospira infections in cattle and buffaloes. The findings contribute to strengthening the one-health strategy by facilitating the design and planning of appropriate control measures to alleviate the burden of leptospirosis in bovines.

Prevalence of Toxoplasma gondii, Leptospira spp., and Coxiella burnetii-associated antibodies in dairy cattle with reproductive disorders.

Background and Aim: In cattle dairy farms, abortions and other reproductive problems due to major infectious diseases are overlooked, and identifying their causative agents is very challenging without a confirmatory diagnosis. Further, a prevalence study in animals will provide important hints of pathogen reservoirs and provide necessary direction to disease burden with appropriate control and biosecurity measures at the farm level. This study aimed to estimate the prevalence of Toxoplasma gondii antibodies in dairy cattle associated with reproductive problems along with coexisting antibodies against abortifacient zoonotic (Coxiella burnetii and Leptospira spp.) pathogens. Materials and Methods: Cattle sera (n = 246) from dairy farms (n = 35) situated in different locations in India were screened for anti-T. gondii and C. burnetii antibodies with enzyme-linked immunoassay and Leptospira spp. antibodies with microscopic agglutination test. Results: The overall prevalence of 11.4% (95% confidence intervals [CIs]: 7.99%-15.96%) antibodies in cattle associated with reproductive problems (p < 0.021) with farm-level seropositivity of 43% was observed. Further, on analysis of screened sera, 49.8% (95% CI: 42.6%-55%) and 77.6% (95% CI: 72%-82.4%) of samples were found to be positive for C. burnetii and Leptospira spp. antibodies, respectively. Moreover, the seropositivity of 91.9% (226/246) for at least one of the screened zoonotic pathogens was observed, indicating antibodies against either of these organisms in association with reproductive disorders (p < 0.005). The percentage of cattle found to have T. gondii antibodies was only 1.8%, whereas 11.5% and 41.6% of cattle were found to have C. burnetii and Leptospira spp. antibodies, respectively. Nevertheless, the predominantly mixed infections observed were of Leptospira and C. burnetii (34.5%), followed by all three infections (4.9%); toxoplasmosis and leptospirosis (3.5%); and toxoplasmosis and Q fever (2.2%). Conclusion: The serological detection of antibodies against these pathogens in cattle may have significant implications for the livestock industry and public health, suggesting the need for continuous surveillance and monitoring of these infections to prevent their spread.

Prevalence of anti-leptospiral antibodies and frequency distribution of Leptospira serovars in small ruminants in enzootic South Peninsular India.

BACKGROUND AND AIM: For understanding the epidemiology of leptospirosis, the confined abundance of several species of pathogenic leptospires and knowledge on the serovar(s) prevalent in the reservoir and carrier hosts may be a useful indicator of transmission to incidental/accidental hosts in a geographical niche. The present study was carried out to ascertain the frequency distribution of Leptospira serovars and the prevalence of anti-leptospiral antibodies in small ruminants (sheep and goats) in the epidemiological units (villages) in the coastal districts of enzootic regions in South Peninsular India. MATERIALS AND METHODS: A total of 1167 serum samples (sheep n=299 and goats n=868) from apparently healthy animals, randomly collected from various epidemiological units were tested in microscopic agglutination test (MAT) using 18 reference Leptospira serovars antigens. RESULTS: The overall seroprevalence of 40% (at 95% confidence intervals [CI]: 36.82-42.43) in small ruminants (44% [95% CI: 40.49-52.26] in sheep and 38% [95% CI: 34.96-41.41] in goats) was observed with the predominance of Icterohaemorrhagiae, Javanica, Australis, Hurstbridge, and Pyrogenes serogroup anti-leptospiral antibodies in the studied region. The Chi-squared test revealed that the presence of anti-leptospiral antibodies is significantly not independent (associated) across the administrative division (Chi-square=105.80, p<0.05) as well as for sheep (Chi-square=34.67, p<0.01) and goats (Chi-square=68.78, p<0.01). Among seropositive samples (n=462 reactors), the MAT was positive for more than one serovar in 73% of sheep (95/131) and 53% of goats (177/331), representing an overall 59% cross-reactive prevalence in small ruminants. The determined frequency distribution (varied among small ruminants) of the employed serovars representing major reactive serogroup was Icterohaemorrhagiae (29.87), Javanica (20.78), Australis (20.35), Hurstbridge (16.23), Pyrogenes (15.8), Djasmin (15.58), Bataviae (15.37), Autumnalis (14.5), Canicola (14.5), Hebdomadis (14.07), Shermani (13.64), Panama (13.42), Sejroe (12.77), etc. CONCLUSION: This study indicates alarmingly high seroprevalence of leptospirosis in small ruminants with existing endemicity in the studied region in South Peninsular India. Further, these prevalent serovars in the administrative division may be of use in the reference panels of antigens in the MAT in both humans and animal disease diagnostic laboratories for effective and timely diagnosis of leptospirosis and to combat the challenges in public health.

Evaluation of recombinant leptospiral surface antigen (Lsa27) lipoprotein for serodiagnosis of human leptospirosis by latex agglutination test.

PURPOSE: Leptospirosis has wide clinical presentations often mimicking other illnesses, thus rapid and simple diagnostics will have facilitated the initial patient management and therapy compared to other inaccessible and laborious tests/assays. METHOD: In this study, the sensitized latex beads coated with purified recombinant outer membrane (OM)-leptospiral surface antigen (Lsa27) lipoprotein of pathogenic Leptospira was evaluated as a diagnostic antigen in latex agglutination test (LAT) for the detection of anti-leptospiral antibodies in the human sera. The prepared rLsa27 latex beads were evaluated with the confirmed microscopic agglutination test (MAT) reactive (at 1:50) Leptospira-specific positive (n = 42) and non-reactive negative (n = 80) sera from human cases suspected of leptospirosis with the history of pyrexia of unknown origin. RESULT: The results revealed the relative diagnostic sensitivity of 90.48 % (confidence interval (CI) at 95 % : 77.4-97.3 %) and diagnostic specificity of 91.35 % (CI at 95 %: 82.8-96.4 %), with an accuracy of 90.98 % (CI at 95 %: 84.44-95.41 %), and the kappa value of 0.8036 ±â€¯0.056 SE (CI at 95 %: 0.69-0.91) with a substantial agreement against gold standard serological MAT. CONCLUSION: The findings suggest that the rLsa27 protein-based LAT can be useful as a simple rapid screening diagnostic test for the detection of anti-leptospiral antibodies in the sera of humans. This rapid test can be complemented by other confirmatory diagnostics for the early detection of Leptospira antibodies which may in turn help in the prompt treatment and mitigates the public health problem at primary health care level.

Expression of Recombinant Leptospiral Surface Lipoprotein-Lsa27 in E. coli and Its Evaluation for Serodiagnosis of Bovine Leptospirosis by Latex Agglutination Test.

The expressed recombinant leptospiral surface adhesion lipoprotein (Lsa27) of pathogenic Leptospira in E. coli was evaluated for the detection of Leptospira antibodies in cattle sera by latex agglutination test (LAT). The Lsa27 lacking signal peptide coding gene sequences from L. interrogans serovar Pomona was amplified (~ 660 bp) by PCR and the amplicon was cloned into pETiteN-HisKan vector. The expressed recombinant Lsa27 histidine-tagged fusion protein (rLsa27) was Ni-NTA affinity purified under denaturation followed by renaturation methods. The purified rLsa27 was characterized by SDS-PAGE and immunoblot, which confirmed the leptospiral protein with a MW of ~ 25 kDa. Further, the prepared sensitized latex beads coated with rLsa27 were evaluated as a diagnostic antigen for detection of pathogenic Leptospira antibodies by using known microscopic agglutination test (MAT) positive (n = 74) and negative (n = 62) sera for Leptospira antibodies in LAT, which revealed the relative diagnostic sensitivity of 91.89% and specificity of 87.10% against the gold standard serological test, MAT. Furthermore, on evaluation of developed rLsa27 LAT using serum samples from cattle associated with the history of abortions and reproductive disorder (n = 309), the relative sensitivity of 96.15%, and specificity of 89.11% were observed. Therefore, this rapid field test using the rLsa27 is first of its kind and it could be used as a screening test for the detection of Leptospira antibodies or it can be complemented by other diagnostics for the diagnosis /surveillance of bovine leptospirosis.

Seroprevalence and distribution of serogroup-specific pathogenic Leptospira antibodies in cattle and buffaloes in the state of Andhra Pradesh, India.

AIM: In this study, the prevalence and the distribution status of Leptospira serogroup-specific antibodies among cattle and buffaloes in enzootic districts of Andhra Pradesh, a South Indian state was carried out. MATERIALS AND METHODS: A total of 426 serum samples were randomly sampled from various villages from Prakasam, Kurnool, Guntur, Chittoor, Srikakulam, Visakhapatnam, and Godavari districts of Andhra Pradesh between 2016 and 2017. Serum samples from cattle (n=106) and buffaloes (n=320) having a history of pyrexia, and reproductive problems such as agalactia, infertility, abortions, and stillbirth. The serum samples were screened for Leptospira-specific antibodies by microscopic agglutination test using a reference panel of 18 live cultures of pathogenic Leptospira serovars. RESULTS: The overall seropositivity of 68.08% (290/426) was observed with 70.8% (75/106) in cattle and 67.18% (215/320) in buffaloes. The frequency distribution of predominant serogroup-specific Leptospira antibodies in the sampled areas was determined against the employed serovars as follows: Icterohaemorrhagiae - 21.38%, Hebdomadis - 18.97%, Australis - 18.62%, Pomona - 17.24%, Sejroe - 15.86%, Tarassovi - 15.86%, Autumnalis - 15.52%, Panama - 14.83%, Shermani - 12.07%, Javanica - 11.38%, Hurstbridge - 11.03%, and Pyrogenes - 10.69%. CONCLUSION: It was evident that bovines had a role in maintaining several predominant Leptospira serovars with the change in the trend over a period. The results from this study would also help in strategizing and mitigating the disease burden in cattle and buffaloes of the enzootic area.

Prevalence of Leptospira serogroup-specific antibodies in cattle associated with reproductive problems in endemic states of India.

In this study, the seroprevalence and distribution of Leptospira in dairy cattle in endemic states of India were investigated in association with reproductive problems of the cattle. A total of 373 cattle serum samples from 45 farms in Maharashtra, Gujarat, Andhra Pradesh, Telangana, Karnataka, Tamil Nadu, Punjab, Haryana, Chhattisgarh, Sikkim and Uttarakhand states were collected from animals with a history of reproductive disorders like abortion, repeat breeding, anoestrus and endometritis, and also from apparently healthy animals. These samples were screened for Leptospira serogroup-specific antibodies by microscopic agglutination test (MAT) using a panel of 18 live reference serovar antigens. The seropositivity of 70.51% (263/373, 95% CI 0.65 to 0.75) was associated with reproductive problems (χ2 = 55.71, p < 0.01) and sampled states (χ2 = 32.99, p < 0.01) and independent of apparently healthy animals (χ2 = 15.6, p > 0.10) and age groups of cattle (χ2 = 0.91, p > 0.10). Further, the odds (risk-relation) of reproductive disorders was 5.29 compared to apparently healthy animals (0.25 odds). The frequency distribution of predominant serogroup-specific Leptospira antibodies were determined against the serovars: Hardjo (27.76%), Pyrogenes (18.63%), Canicola and Javanica (17.49%), Hebdomadis (17.11%), Shermani and Panama (16.73%), Djasiman (16.35%), Tarassovi, Grippotyphosa and Pomona (15.97%), Icterohaemorrhagiae (15.59%), Copenhageni (14.83%), Australis (13.69%), Kaup and Hurstbridge (10.65%), Bankinang (10.27%) and Bataviae (9.51%). In conclusion, dairy cattle have a role in maintaining important several serovars besides well-known Hardjo serovar in endemic states of India and warrant mitigating measures to reduce the incidence of cattle leptospirosis including need for an intensive surveillance programme, preventive vaccination and control strategies.