Rickettsial diseases and ectoparasites from military bases in Japan

Ecology of Bats, Their Ectoparasites, and Associated Pathogens on Saint Kitts Island

Ectoparasites of bats and bat-associated pathogens are poorly studied in the Lesser Antilles Islands. We report on an 11-mo field study on Saint Kitts Island of bat populations, their associated ectoparasites, and pathogens. We report on five ectoparasite species, including four Streblidae (Diptera) and a Spinturnicidae (Acari). Several genotypes of unnamed Bartonella were isolated from bats and ectoparasites. Microfilaria of an undetermined Litomosoides spp. were detected in blood from Artibeus jamaicensis Leach (Chiroptera: Phyllostomidae) (and associated ectoparasites: Trichobius intermedius Peterson and Hurka (Diptera: Streblidae) and Periglischrus iheringi Oudemans (Acari: Spinturnicidae)). In addition, an Ehrlichia sp. and Rickettsia africae were detected in the blood of several bat species. Our study is one of the first surveys of ectoparasite-borne pathogens in wild mammals from St. Kitts.

Rickettsia felis: The Complex Journey of an Emergent Human Pathogen

Rickettsia felis is an obligate intracellular bacterium that is different from other officially recognized rickettsial species. It has multiple genes of different origins, an incubation temperature of less than 32°C, and a conjugative plasmid. This Rickettsia is commonly detected in febrile patients in sub-Saharan Africa. R. felis is frequently detected in cat fleas, but recently mosquitoes have been suspected to be able to transmit the bacterium. However, many aspects of the ecology and epidemiology of R. felis are not completely understood and remain to be uncovered. We aim here to give an update of the current knowledge about this fascinating organism.

Rickettsia felis, an Emerging Flea-Borne Rickettsiosis

Rickettsia felis is an emerging insect-borne rickettsial pathogen and the causative agent of flea-borne spotted fever. First described as a human pathogen from the USA in 1991, R. felis is now identified throughout the world and considered a common cause of fever in Africa. The cosmopolitan distribution of this pathogen is credited to the equally widespread occurrence of cat fleas (Ctenocephalides felis), the primary vector and reservoir of R. felis. Although R. felis is a relatively new member of the pathogenic Rickettsia, limited knowledge of basic R. felis biology continues to hinder research progression of this unique bacterium. This is a comprehensive review examining what is known and unknown relative to R. felis transmission biology, epidemiology of the disease, and genetics, with an insight into areas of needed investigation.

The Importance of Ticks in Q Fever Transmission: What Has (and Has Not) Been Demonstrated?

Q fever is a widespread zoonotic disease caused by Coxiella burnetii, a ubiquitous intracellular bacterium infecting humans and a variety of animals. Transmission is primarily but not exclusively airborne, and ticks are usually thought to act as vectors. We argue that, although ticks may readily transmit C. burnetii in experimental systems, they only occasionally transmit the pathogen in the field. Furthermore, we underscore that many Coxiella-like bacteria are widespread in ticks and may have been misidentified as C. burnetii. Our recommendation is to improve the methods currently used to detect and characterize C. burnetii, and we propose that further knowledge of Coxiella-like bacteria will yield new insights into Q fever evolutionary ecology and C. burnetii virulence factors.