Rickettsia felis in Fleas, Southern Ethiopia, 2010

TO THE EDITOR: Fleas (order Siphonaptera) are obligate hematophagous insects. They are laterally flattened, holometabolous, and wingless ectoparasites. More than 2,500 species of flea, belonging to 16 families and 238 genera, have been described. A minority of these genera live in close association with humans (synanthropic), including fleas of these species: Pulex irritans, Ctenocephalides felis, Ctenocephalides canis, Xenopsylla cheopis, Nosopsyllus fasciatus, Echidnophaga gallinacea, and Tunga penetrans (1). Many fleas are capable of transmitting the following pathogens to their hosts: bacteria (e.g., Rickettsia typhi, R. felis, Yersinia pestis, and many Bartonella spp.); viruses (e.g., myxoma virus); protozoa (e.g., Trypanosoma spp.); or helminths (e.g., Hymenolepis spp.) (2). Ctenocephalides spp. fleas are of special interest as main reservoirs and vectors of R. felis, because this agent causes an emerging disease, fleaborne rickettsiosis. The distribution and prevalence of this disease have not been well studied. Symptoms of this disease range from mild to moderate and include fever, cutaneous rash, and sometimes an inoculation eschar (3,4). R. felis can also infect at least 10 other species of arthropods, including P. irritans fleas, trombiculid and mesostygmata mites, hard and soft ticks, and booklice (5,6).     

Human Rickettsia felis infection, Canary Islands, Spain

We report the first cases of human infection by Rickettsia felis in the Canary Islands. Antibodies against R. felis were found in 5 adsorbed serum samples from 44 patients with clinically suspected rickettsiosis by Western blot serology. Fleas from 1 patient's dog were positive for R. felis by polymerase chain reaction.     

Rickettsia felis in fleas, Western Australia

This study is the first confirmation of Rickettsia felis in Australia. The organism was identified from 4 species of fleas obtained from dogs and cats in Western Australia, by using polymerase chain reaction amplification and DNA sequencing of the citrate synthase and outer membrane protein A genes.     

Rickettsia typhi and R. felis in rat fleas (Xenopsylla cheopis), Oahu, Hawaii

Rickettsia typhi (prevalence 1.9%) and R. felis (prevalence 24.8%) DNA were detected in rat fleas (Xenopsylla cheopis) collected from mice on Oahu Island, Hawaii. The low prevalence of R. typhi on Oahu suggests that R. felis may be a more common cause of rickettsiosis than R. typhi in Hawaii.     

Rickettsia felis in Xenopsylla cheopis, Java, Indonesia

Rickettsia typhi and R. felis, etiologic agents of murine typhus and fleaborne spotted fever, respectively, were detected in Oriental rat fleas (Xenopsylla cheopis) collected from rodents and shrews in Java, Indonesia. We describe the first evidence of R. felis in Indonesia and naturally occurring R. felis in Oriental rat fleas.     

Human Infection with Rickettsia felis, Kenya

To determine the cause of acute febrile illnesses other than malaria in the North Eastern Province, Kenya, we investigated rickettsial infection among patients from Garissa Provincial Hospital for 23 months during 2006–2008. Nucleic acid preparations of serum from 6 (3.7%) of 163 patients were positive for rickettsial DNA as determined by a genus-specific quantitative real-time PCR and were subsequently confirmed by molecular sequencing to be positive for Rickettsia felis. The 6 febrile patients’ symptoms included headache; nausea; and muscle, back, and joint pain. None of the patients had a skin rash.     

Rickettsia felis infection, Tunisia

We report, for the first time, serologic evidence of Rickettsia felis and R. aeschlimannii infections acquired in Tunisia from 1998 to 2003. We found that most patients with antibodies against both R. conorii and R. typhi had serologic evidence of R. felis infection.     

Bartonella quintana and Rickettsia felis in Gabon

We detected Rickettsia felis DNA in Ctenocephalides felis and Bartonella quintana DNA in 3 Pulex irritans fleas taken from a pet Cercopithecus cephus monkey in Gabon, sub-Saharan Africa. This is the first report of B. quintana in the human flea.