Prevalence of Borrelia burgdorferi Sensu Lato in Pet Dogs and Associated Ticks in Pakistan

Borrelia burgdorferi sensu lato is the etiological agent of Lyme disease. We investigated presence of B. burgdorferi s.l. in 600 pet dogs and 391 tick pools using PCR assay and sequencing in the Lahore City Metropolitan Area, Pakistan. Potential association of various risk factors with occurrence of Lyme borreliosis was also estimated via univariate and multivariate logistic regression. From each dog, blood and tick samples were collected and then tick species were identified. DNA extraction was followed by detection of 16S rRNA signature gene using B. burgdorferi s.l. specific primers through conventional PCR. We found that 4.3% dogs and 8.9% tick pools were positive for B. burgdorferi s.l. Rhipicephalus sanguineus (86.5%) was the most abundant tick species. 57.1% I. gibbosus and 8.4% R. sanguineus pools tested positive for B. burgdorferi s.l. Phylogenetically, our sequences clustered with B. burgdorferi sensu stricto, B. bavariensis, B. garinii, and B. bissettii sequences sourced from different hosts worldwide. Sequences showed 40.2%-99.1% sequences identity among them and 39%-98.3% with previously reported sequences on NCBI GenBank. Our sequences were submitted in NCBI GenBank under accession numbers MW547399-MW547405. Four animal-related: age (p=0.03), weight (p<0.05), sex (p=0.03), and breed (p<0.05), while three management-related risk factors: type of housing (p<0.05), tick infestation (p=0.007), and travel history (p=0.003) were significantly (p < 0.05) associated with occurrence of Lyme borreliosis. This is the first report on the presence of B. burgdorferi s.l. in Pakistan indicating the need for more comprehensive molecular surveys to estimate its prevalence in wider geographical areas and additional animal species as well as human population.

Automated summary

In this study, the presence of B. burgdorferi s.l. in pet dogs and tick pools in the Lahore City Metropolitan Area, Pakistan was investigated. It was found that a certain percentage of dogs and tick pools tested positive for B. burgdorferi s.l. Through phylogenetic analysis, the sequences were clustered with B. burgdorferi sensu stricto, B. bavariensis, B. garinii, and B. bissettii sequences from different hosts worldwide. Statistical analysis revealed significant associations between certain animal-related and management-related factors and occurrence of Lyme borreliosis.