Molecular Detection and Characterization of <i>Rickettsia asembonensis</i> in Human Blood, Zambia
Lavel C. Moonga, Kyoko Hayashida, Namwiinga R. Mulunda, Yukiko Nakamura, James Chipeta, Hawela Moonga, Boniface Namangala, Chihiro Sugimoto, Zephaniah Mtonga, Mable Mutengo, Junya Yamagishi
Abstract
R ickettsia asembonensis is a fleaborne rickettsia close- ly related to Rickettsia felis and is thus referred to as an R. felis-like organism. R. asembonensis was first detected in cat fleas in Kenya and subsequently reported worldwide (1,2). Although R. felis has been increasingly recognized as a human infective agent that can cause human febrile disease, the infectivity and pathogenicity of R. asembonensis in humans is largely unknown. Recent investigations in patients with febrile illness and petechial lesions identified R. asembonensis DNA and antibodies for rickettsial antigens in Malaysia (3,4). Furthermore, R. asembonensis was isolated in cellular cultures from patients in Peru with acute febrile illness and confirmed by sequencing (5). These reports suggest the possibility of R. asembonensis as a human infective agent. However, no direct evidence of R. felis and R. asembonensis as an etiologic agent of human illness has been established. A previous study in Zambia revealed the predominant existence of R. asembonensis and R. felis in cat fleas (6). Our study investigates the presence of these rickettsiae in human blood in Zambia.