Serology, molecular detection and risk factors of Ehrlichia canis infection in dogs in Costa Rica

Abstract

A cross-sectional study combining different serological and molecular techniques for the detection of Ehrlichia species in dogs and their ticks was carried out with data from all regions of Costa Rica. A seroprevalence of 32.1% (131/408), and infection with E. canis of 3.2% (13/407) was found, whereas 6.9% (9/130) of ticks attached to the dogs were PCR positive to E. canis. Higher prevalences were found outside the Greater Metropolitan Area (GMA). Risk factors associated with E. canis seropositivity were age, between 2 and 7 years (RR: 1.6, 95% CI: 1.2-2.2) and 8-15 years (RR: 1.8, 95% CI: 1.2-3.0), number of dogs/total of households [Dogs per Household Ratio (DHR) ≥3.1 (RR: 2.0; 95% CI: 1.4-3.0)], number of dogs infested with at least one tick/total of dogs sampled [Tick Infestation Prevalence (TIP)≥31% (RR: 2.1; 95% CI:1.3-3.3)] and living outside the GMA (RR: 1.7; 95% CI: 1.2-2.4) and being a mixed-breed dog (RR: 1.5; 95% CI: 1.1-2.1). Risk factors for E. canis PCR positive dogs were a depressive attitude (OR: 11.2; 95% CI: 1.1-115.9), fever (OR:4.8; 95% CI:1.2-19.3), DHR≥3.1 (OR: 5.7; 95% CI:1.7-19.2)], number of ticks/total of dogs sampled [Tick Distribution Ratio (TDR) ≥2.1 (OR: 6.5; 95% CI: 1.3-31.8)], and TIP≥40% (OR: 5.7; 95% CI: 1.7-19.2). This paper describes E. canis seroprevalence, PCR prevalence and tick analysis in dogs from Costa Rica, with associated clinical signs and owner perceptions. In summary, most of the E. canis infections in dogs in our country seemed to pass unnoticed by owners. Since most of the seropositive dogs (97.7%, 131/134) were negative for E. canis DNA in their blood, it is important to determine in future studies if these dogs recovered from the E. canis infection without any medication, or are persistently infected, and will develop chronic disease.

Molecular detection of Bartonella, Ehrlichia and Mycoplasma in feral dogs of El Pedregal de San Angel Ecological Reserve in Mexico City

“…These results contribute to determining the negative relationship between feral dogs and wild animals of REPSA regarding disease transmission. Ehrlichia canis (the causative agent of canine monocytic ehrlichiosis) is the main rickettsial agent registered in dogs of the Neotropical region, with prevalence ranging between 15 and 70% (BARRANTES-GONZÁLEZ et al, 2016;MONTENEGRO et al, 2017;ROTONDANO et al, 2017;GEIGER et al, 2018;PAULINO et al, 2018). Clinical signs of an E. canis infection can be variable, depending on the strain, the immune response of the dog, and the presence of concomitant infections with other tick or flea-borne pathogens (SAINZ et al, 2015), however, no clinical signs were observed in the animals captured.…”

“…With respect to the feral fauna, it has been particularly worrisome with the presence of antibody titers in dogs against rabies, Toxoplasma gondii, and parvovirus (SUZÁN & CEBALLOS, 2005), suggesting an important risk for public and ecosystem health. However, no studies have been conducted to evaluate the presence of tick-borne and flea-borne pathogens in feral dogs, although previous studies have shown the presence of Bartonella henselae in feral dogs from UK using serological techniques (BARNES et al, 2000), and Ehrlichia canis from Costa Rica using serological and molecular techniques (BARRANTES-GONZÁLEZ et al, 2016).…”

Characterization of Anaplasma spp. infection in dogs from Costa Rica

“…Interviews, clinical records and sampling was performed ultimately from 408 dogs. Population study, sampling methodology and period of study are described in Barrantes-González et al (2016).…”

Understanding <i>Ehrlichia canis</i> Infections in Dogs of Costa Rica: Hematological Findings and Indicative Clinical Signs

“…The total sample size was estimated to be 385 individuals (50% prevalence, 95% confidence) for a population of more than 40,000 dogs, calculated using Win Episcope 2.0. More details of the population studied, sampling methodology and period of study are described in Barrantes-González et al [16].…”

“…PCR products (389 to 396 bp) were purified using the QIAquick kit (QIAGEN®), proceeding according to the manufacturer's instructions, and sent to Macrogen (Seoul, Korea) for sequencing. Further detailed molecular analysis methodology is described in Barrantes-González et al [16].…”