Seroprevalence and Genotypic Analysis of Ehrlichia canis Infection in Dogs and Humans in Cauca, Colombia

Abstract

Ehrlichia canis infections have been reported in humans in Venezuela and Costa Rica. In this study, 506 healthy residents and 114 dogs from four municipalities (Cauca, Colombia) were surveyed and blood samples collected. Antibodies to E. canis in human and canine sera were evaluated using the Tandem repeat protein 19 (TRP19) peptide ELISA and indirect immunofluorescence assay (IFA). Ehrlichia canis TRP19 antibodies were detected in only 1/506 human sera, but the single positive sample was negative by IFA. The majority (75/114; 66%) of dogs surveyed had antibodies to the E. canis TRP19 peptide by ELISA, and eight randomly selected sera were further confirmed by E. canis IFA. Genomic DNA samples obtained from 73 E. canis TRP19 ELISA–positive dog blood samples were examined by PCR targeting the 16S rRNA gene. Ehrlichia canis 16S rRNA was amplified in 30 (41%) of the dogs, and 16 amplicons were selected for DNA sequencing, which confirmed that all were E. canis. A second PCR was performed on the 16 confirmed E. canis 16S rRNA PCR–positive samples to determine the TRP36 genotype by amplifying the trp36 gene. TRP36 PCR amplicon sequencing identified nine dogs infected with the U.S. E. canis TRP36 genotype (56%), one dog with the Brazilian genotype (6%), and six dogs with the Costa Rican genotype (38%). Moreover, these molecular genotype signatures were consistent with serologic analysis using TRP36 genotype–specific peptides. Notably, there was no serologic evidence of E. canis infection in humans, suggesting that E. canis infection in dogs in Cauca is not associated with zoonotic human infection.

Seroprevalence canine survey for selected vector-borne pathogens and its relationship with poverty in metropolitan Pereira, Colombia, 2020

“…This study was performed in Colombia, where there is also a lack of seroprevalence studies about Ehrlichia spp. (less than 20 in PubMed database), 11 in canine populations, none in Pereira and Risaralda ( Arroyave et al, 2020b ; Bonilla-Aldana et al, 2021 ; Forero-Becerra et al, 2021 ; Hidalgo et al, 2009 ; McCown et al, 2014 ; Miranda and Mattar, 2015 ; Pesapane et al, 2019 ; Vargas-Hernandez et al, 2012 ). Given the high seroprevalence obtained in an area with ticks' infestation (data not shown), the potential risk for zoonotic transmission to humans remains latent, deserving immediate seroprevalence studies.…”

Seroprevalence Canine Survey for Selected Vector-Borne Pathogens of and Its Relationship with Poverty in Metropolitan Pereira, Colombia, 2020

“…This study was performed in Colombia, where there is also a lack of seroprevalence studies about Ehrlichia spp. (less than 20 in PubMed database), 11 in canine populations, none in Pereira and Risaralda [4,19,20,[46][47][48][49][50]. Given the high seroprevalence obtained in an area with ticks' infestation, the potential risk for zoonotic transmission to humans remains latent, deserving immediate seroprevalence studies.…”

Whole Genome Sequencing and Comparative Analysis of the First Ehrlichia canis Isolate in China

“…While most dogs with CME recover through treatment with doxycycline or rifampicin, alongside appropriate supportive care, chronic cases leading to fatalities are not uncommon [ 4 , 7 ]. Notably, E. canis infections have also been reported in humans [ 8 , 9 ].…”