Personal and household factors involved in recentRickettsiaexposure in a rural population from Yucatán, Mexico

Abstract

The aim of the study was to describe the epidemiological factors associated with the risks of recent Rickettsia exposure in inhabitants of a rural population from Yucatán, Mexico. The study included 130 inhabitants from Maxcanú, Yucatán. Blood samples were collected to detect IgM and IgG antibodies against Rickettsia typhi and Rickettsia rickettsii by an indirect immunofluorescence antibody test. Additionally, nested polymerase chain reaction was performed to amplify fragments of the 17kDa and sca5 genes. Previously, an epidemiological questionnaire was applied focused on collecting information on personal and housing exposure variables related to the recent infection with Rickettsia to determine epidemiological associations. Results that exhibited a p‐value < .25 were included in a generalized multinomial logistic linear model to determine the variables involved with the risk of contact or Rickettsia infection. In all, 76% (99/130) of the participants presented with immunoglobulin titres against the Rickettsia species evaluated, while rickettsial DNA was detected in 35.4% (46/130) of the participants. The association analysis with the personal exposure variables showed that the productive age group (OR = 0.32; 95% CI = 0.10–1.03) and the elders group (OR = 0.12; 95% CI = 0.01–0.83) were protective factors for recent infection with R. typhi, taking as reference the school group. The presence of a family orchard in the home (OR = 7.56; 95% CI = 1.62–35.29) was a risk factor for recent infection with R. rickettsii. Presumably, the presence of ectoparasites (OR = 2.71; 95% CI = 0.90–8.09) at home was a risk factor for recent infection with both Rickettsia species. Recent infection was demonstrated in inhabitants from Maxcanú, Yucatán. A high seropositive frequency was obtained. The results highlight the importance of the family garden and the presence of ectoparasites in the home as risk factors associated with recent infection with Rickettsia in inhabitants from Maxcanú.

Molecular confirmation of Rickettsia parkeri in humans from Southern Mexico

“…This finding may also be associated with early infection with Rickettsia spp. as is the bacteremia (Torres‐Castro et al., 2020).…”

“…As part of an ongoing study to identify the eco‐epidemiology of rickettsiosis in Southeastern Mexico, whole blood samples were collected from 130 people distributed in 60 households in the rural community of Maxcanu (20°33′, 20°46′N–89°53′, 90°24′W) where an active focus of murine typhus is present (Figure 1). Blood samples were taken by qualified health personnel (Torres‐Castro et al., 2020). Maxcanu has an altitude of 10 m above sea level with an average annual temperature of 27.4ºC, and an annual rainfall of 1080 mm.…”

“…The samples were eluted in 100 µl. To detect the presence of DNA from members of the genus Rickettsia and to identify the infecting species, two PCRs were performed to amplify highly conserved Rickettsia fragments in the 17 kDa and sca5 genes, using standard methods previously reported (Portillo et al, 2017;Torres-Castro et al, 2020). Semi-nested PCR of the sca5 gene allows the infective Rickettsia group to be determined: The sequences obtained in the present study were aligned with other reference sequences deposited in GenBank® using the CLUSTAL W algorithm in MEGA 6.0.…”

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

“…Recently, studies in a rural locality in the State of Yucatan, Mexico, performed by Torres-Castro et al [ 18 , 19 , 20 ], found that 90% of the people exposed to Rickettsia sp. infection (antibodies) were dog owners, and 70% had more than one dog in their household.…”

“…Since people from Maxcanú showed exposure to TG Rickettsia [ 18 ], and there is evidence of R . typhi infecting domiciliated dogs in the studied region [ 9 , 10 , 21 ], this research addresses the following questions: what is the occurrence of the TG Rickettsia natural infection in domiciliated dogs?…”