Molecular Detection of Rickettsia typhi in Cats and Fleas

Abstract

Background Rickettsia typhi is the etiological agent of murine typhus (MT), a disease transmitted by two cycles: rat-flea-rat, and peridomestic cycle. Murine typhus is often misdiagnosed and underreported. A correct diagnosis is important because MT can cause severe illness and death. Our previous seroprevalence results pointed to presence of human R . typhi infection in our region; however, no clinical case has been reported. Although cats have been related to MT, no naturally infected cat has been described. The aim of the study is to confirm the existence of R . typhi in our location analyzing its presence in cats and fleas.Methodology/Principal Findings221 cats and 80 fleas were collected from Veterinary clinics, shelters, and the street (2001-2009). Variables surveyed were: date of collection, age, sex, municipality, living place, outdoor activities, demographic area, healthy status, contact with animals, and ectoparasite infestation. IgG against R . typhi were evaluated by indirect immunofluorescence assay. Molecular detection in cats and fleas was performed by real-time PCR. Cultures were performed in those cats with positive molecular detection. Statistical analysis was carried out using SPSS. A p < 0.05 was considered significant.Thirty-five (15.8%) cats were seropositive. There were no significant associations among seropositivity and any variables. R . typhi was detected in 5 blood and 2 cultures. High titres and molecular detection were observed in stray cats and pets, as well as in spring and winter. All fleas were Ctenocephalides felis. R . typhi was detected in 44 fleas (55%), from shelters and pets. Co-infection with R . felis was observed.ConclusionsAlthough no clinical case has been described in this area, the presence of R . typhi in cats and fleas is demonstrated. Moreover, a considerable percentage of those animals lived in households. To our knowledge, this is the first time R . typhi is detected in naturally infected cats.

Prevalence of Rickettsia and Bartonella species in Spanish cats and their fleas

“…Based on the results of the study described herein, it appears unlikely that domestic cats are an effective reservoir host for R. typhi and it is possible that other animals work as reservoir hosts for R. typhi (Eisen and Gage ). However, 15.8% prevalence in naturally infected cats was found in a recent study carried out in northeast Spain (Nogueras et al This discrepancy between the two studies might be due to the different origin of the cats involved (veterinary clinics vs veterinary clinics, shelters, and the street) or the sample area. A high variability in prevalence (none vs 62.9%) was observed according to the area sampled (Nogueras et al It is important to maintain a high level of surveillance for this infectious disease.…”

“…Two cycles are involved in R. typhi transmission: a classical cycle that involves rats as a reservoir and Xenopsylla cheopis as a vector, and a peridomestic cycle, involving cats, dogs, peridomestic rodents, and their fleas, Ctenocephalides felis ) (Gillespie et al In Spain, some epidemiological studies have shown a seroprevalence of R. typhi of up to 18% in human populations (Santibáñez et al Although the maintenance of R. typhi in the peridomestic cycle is of potential public health importance and a major health risk, the extent of exposure to this pathogen remains incompletely described in cats and their fleas. In Spain, only one study conducted in northeast Spain provides information related to R. typhi infection in cats and their fleas (Nogueras et al …”

Serosurvey of Rickettsia typhi and Rickettsia felis in HIV‐infected patients

“…were found in IDUs from Harlem . In our region, a cycle involving pets has been described . Thus, it may be incorrect to postulate a higher risk among people with poor living conditions than among people living in homes.…”

Shell-vial culture and real-time PCR applied to Rickettsia typhi and Rickettsia felis detection

“…Presence of DNA of either R. typhi or R. felis had been analyzed previously in Ctenocephalides felis collected from cats and dogs that had been attended at a veterinary clinic (Nogueras et al 2011(Nogueras et al , 2013a. Fleas had been individually triturated in 100 lL of brain-heart infusion (BHI).…”

“…MT is one of the most prevalent Rickettsioses worldwide distributed (CDC 2009;Dzul-Rosado et al 2013;Gillespie et al 2009;Nogueras et al 2013a;Phongmany et al 2006;Znazen et al 2013); however, its real prevalence is unknown in many countries. MT is usually a mild and acute disease, whose main clinical signs are fever and rash.…”