Identification of rickettsiae from wild rats and cat fleas in Malaysia

Abstract

Abstract. Rickettsioses are emerging zoonotic diseases reported worldwide. In spite of the serological evidence of spotted fever group rickettsioses in febrile patients in Malaysia, limited studies have been conducted to identify the animal reservoirs and vectors of rickettsioses. This study investigated the presence of rickettsiae in the tissue homogenates of 95 wild rats and 589 animal ectoparasites. Using PCR assays targeting the citrate synthase gene (gltA), rickettsial DNA was detected in the tissue homogenates of 13 (13.7%) wild rats. Sequence analysis of the gltA amplicons showed 98.6-100% similarity with those of Rickettsia honei/R. conorii/R. raoultii (Rickettsiales: Rickettsiaceae). Sequence analysis of outer membrane protein A gene (ompA) identified Rickettsia sp. TCM1 strain from two rats. No rickettsia was detected from Laelaps mites, Rhipicephalus sanguineus and Haemaphysalis bispinosa ticks, and Felicola subrostratus lice in this study. R. felis was identified from 32.2% of 177 Ctenocephalides felis fleas. Sequence analysis of the gltA amplicons revealed two genotypes of R. felis (Rf31 and RF2125) in the fleas. As wild rats and cat fleas play an important role in the enzoonotic maintenance of rickettsiae, control of rodent and flea populations may be able to reduce transmission of rickettsioses in the local setting.

Rickettsial seropositivity in the indigenous community and animal farm workers, and vector surveillance in Peninsular Malaysia

“…35 A R. felis -like organism (RFLO) was detected in a febrile patient, 43 cat fleas and cynomolgus monkeys in recent Malaysian studies. 44, 45, 46 The findings in this study indicate that 22.5% of the indigenous populations and 16.1% of farm workers were previously been exposed to R. felis . In contrast, none of the urban blood donors tested was seropositive to R. felis (Table 1).…”

“…sanguineus and Haemaphysalis ticks infesting peri-domestic animals in the rural villages (Table 4). Previously, closely related strains of R. raoultii were reported in Malaysian wild rats 45 and Amblyomma spp. parasitizing wild snakes.…”

Rickettsial Infections in Monkeys, Malaysia

“…Although Rickettsia spp. RF2125 and Rf31 have been identified from cat fleas in Malaysia ( 3 ), the presence of Anaplasma bovis in monkeys is not known.…”

Emerging infectious diseases with cutaneous manifestations

“…The prevalence of R felis in flea vectors is approximately 21% to 32%, but can be as high as 90% in South America, which highlights the possibility that it is a more common human infection. 121,122 R felis is likely underreported because of a lack of awareness and laboratory capabilities.…”

“…Management of the local reservoirs, including rodents, dogs, and cats, are important in tackling the spread of R felis. 122 Tick-borne lymphadenopathy. First described in 1997, tick-borne lymphadenopathy (TIBOLA) is the association of the Dermacentor tick vector with scalp eschar and cervical lymphadenopathy.…”