Epidemiological Study of the Occurrence of Typhus Group Rickettsia Natural Infection in Domiciliated Dogs from a Rural Community in South-Eastern Mexico

Abstract

The aim is to describe the Typhus group (TG) Rickettsia infection in dogs and to identify factors associated with this infection. We collected blood samples and gathered exposure and clinical data of 142 dogs from a rural community of Yucatan. The Rickettsia group was determined by semi-nested PCR. Generalized linear models with binomial error distribution were used to model the associated factors from the dog sample for risk ratio (RR) estimation. Thirty-four dogs (23.9%) showed molecular evidence of TG Rickettsia DNA. The multivariate model showed that mixed-breed dogs (RR = 0.06) and dogs that had received antiparasitic treatment (RR = 0.049) had a lower risk of getting infected, taking as reference the purebred group and the non-treated dogs, respectively. Looking at variable interactions, adult dogs without outdoor activities had a lower infection risk than puppies (RR = 0.26). Among dogs with antiparasitic treatment, females had a higher infection risk than male dogs (RR = 26.2). The results showed enzootic TG Rickettsia circulation in dogs of a rural community. The factors outdoor activities, age and previous antiparasitic treatment, as well as the clinical variables signs of hemorrhages and epistaxis, were associated with a less chance of natural infection in the studied dogs. Prevention and control of the enzootic transmission risk of TG Rickettsia should help to reduce the potential zoonotic transmission of this pathogen.

An unusual identification ofRickettsia parkeriin synanthropic rodents and domiciliated dogs of a rural community from Yucatán, Mexico

“…In the specific case of R. parkeri , the main biological vectors are hard ticks of the genus Amblyomma , which have been associated, especially in their immature stages, with synanthropic rodents in the USA (Cumbie et al, 2020) and southeastern Mexico (Dzul‐Rosado et al, 2021), including M. musculus (Rodríguez‐Vivas et al, 2016). Therefore, in a similar way as with other accidental hosts and carriers of Rickettsia from the study region (Torres‐Castro, Reyes‐Novelo, et al, 2022), the necessary epidemiological elements (biological vectors, reservoirs, and susceptible hosts) exist (Lu et al, 2019) that allow the establishment and circulation of R. parkeri in synanthropic rodent populations such as M. musculus . In this sense, it is accepted that members of the SFG, including R. parkeri , are naturally maintained by vertical and horizontal transmission among the arthropod vectors (ticks) and susceptible vertebrate hosts, respectively (Grasperge, Wolfson, & Macaluso, 2012; Rocha et al, 2022).…”

“…Domestic dogs participate notably in the urban and rural transmission cycles of some Rickettsia species (Dzul‐Rosado et al, 2021; Fournier et al, 2020; Torres‐Castro et al, 2020; Torres‐Castro, Reyes‐Novelo, et al, 2022), therefore, they are one of the most studied mammal hosts in Mexico (Sánchez‐Montes et al, 2021), especially, in Yucatán (Arroyo‐Ramírez et al, 2022). Their importance is also reflected in the epidemiological fact that some active cases of rickettsiosis in humans have been associated with Rickettsia infection in these companion animals due to the closeness and coexistence with them, favouring the possibility of their ectoparasites passing to humans (Breitschwerdt et al, 1987).…”

“…Their importance is also reflected in the epidemiological fact that some active cases of rickettsiosis in humans have been associated with Rickettsia infection in these companion animals due to the closeness and coexistence with them, favouring the possibility of their ectoparasites passing to humans (Breitschwerdt et al, 1987). Likewise, domiciliated dogs are hosts of different genera of vector ticks (Martínez‐Ortiz et al, 2019) that can eventually parasitize humans and generate the zoonotic transmission cycle of Rickettsia (Saraiva et al, 2014; Torres‐Castro, Reyes‐Novelo, et al, 2022).…”

“…In domiciled dogs from Yucatan, the occurrence of different Rickettsia species has been described, including R. akari (TRG) (Zavala‐Castro et al, 2009), R. typhi (Dzul‐Rosado et al, 2017; Martínez‐Ortiz et al, 2016), R. parkeri (Ojeda‐Chi et al, 2019), and unidentified members of TG (Torres‐Castro, Reyes‐Novelo, et al, 2022). Similarly, serological surveys in these animals have shown the presence of antibodies (IgG and IgM) against members of the SFG and TG (Dzul‐Rosado et al, 2021).…”

Effect of Breed on Hematological and Biochemical Parameters of Apparently Healthy Dogs Infected with Zoonotic Pathogens Endemic to the Mediterranean Basin

“…In this paper, we also found a high prevalence, for the first time, in the St. Bernard breed, classified in group two of the Federation Cynologique Internationale (FCI) [53], together with Boxers and Dobermann Pinschers, canine breeds with a high seroprevalence of L. infantum infection [16]. Related to R. ricketsii infection, no data about a different prevalence in canine breeds exist, but several studies have reported a differential prevalence according to lifestyle (outdoor more than indoor) [54,55] and crossbreeds compared to pure breeds (more prevalent in the former) [56].…”