Maina Alice N, Fogarty Carrie, Krueger Laura, Macaluso Kevin R, Odhiambo Antony, Nguyen Kiet, Farris Christina M, Luce-Fedrow Alison, Bennett Stephen, Jiang Ju, Sun Sokanary, Cummings Robert F, Richards Allen L
Naval Medical Research Center, Silver Spring, MD, United States of America.
Orange County Mosquito and Vector Control District, Garden Grove, CA, United States of America.
PLoS One. 2016 Aug 18;11(8):e0160604. doi: 10.1371/journal.pone.0160604. eCollection 2016.
Due to a resurgence of flea-borne rickettsioses in Orange County, California, we investigated the etiologies of rickettsial infections of Ctenocephalides felis, the predominant fleas species obtained from opossums (Didelphis virginiana) and domestic cats (Felis catus), collected from case exposure sites and other areas in Orange County. In addition, we assessed the prevalence of IgG antibodies against spotted fever group (SFGR) and typhus group (TGR) rickettsiae in opossum sera. Of the 597 flea specimens collected from opossums and cats, 37.2% tested positive for Rickettsia. PCR and sequencing of rickettsial genes obtained from C. felis flea DNA preparations revealed the presence of R. typhi (1.3%), R. felis (28.0%) and R. felis-like organisms (7.5%). Sera from opossums contained TGR-specific (40.84%), but not SFGR-specific antibodies. The detection of R. felis and R. typhi in the C. felis fleas in Orange County highlights the potential risk for human infection with either of these pathogens, and underscores the need for further investigations incorporating specimens from humans, animal hosts, and invertebrate vectors in endemic areas. Such studies will be essential for establishing a link in the ongoing flea-borne rickettsioses outbreaks.
由于加利福尼亚州奥兰治县跳蚤传播的立克次体病再度流行，我们对从负鼠（弗吉尼亚负鼠）和家猫（家猫）身上采集的主要跳蚤种类猫栉首蚤立克次体感染的病因进行了调查，这些跳蚤是从奥兰治县的病例暴露地点和其他地区采集的。此外，我们评估了负鼠血清中针对斑点热群（SFGR）和斑疹伤寒群（TGR）立克次体的IgG抗体的流行情况。在从负鼠和猫身上采集的597份跳蚤标本中，37.2%的标本立克次体检测呈阳性。从猫栉首蚤跳蚤DNA制剂中获得的立克次体基因的PCR和测序显示存在伤寒立克次体（1.3%）、猫立克次体（28.0%）和猫立克次体样生物（7.5%）。负鼠的血清含有TGR特异性抗体（40.84%），但不含有SFGR特异性抗体。在奥兰治县的猫栉首蚤中检测到猫立克次体和伤寒立克次体，凸显了人类感染这两种病原体中任何一种的潜在风险，并强调有必要进一步开展调查，纳入流行地区人类、动物宿主和无脊椎动物媒介的标本。此类研究对于在当前跳蚤传播的立克次体病疫情中建立联系至关重要。
