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).     

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.     

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.     

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.     

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.     

用PCR方法检出蚤类携带巴尔通体

目的调查我国巴尔通体宿主动物体表寄生蚤类是否携带巴尔通体。方法2003年6～7月在云南省大理州云龙县居民区采集家猫、狗、鼠类等体表寄生蚤，用3对巴尔通体属特异性引物BhCS．781p—BhCS．1137n、Bh．311p—Bh．452n和TI1e．455p—TA1a．885n进行聚合酶链反应(PCR)，扩增巴尔通体gltA和16S～23S rRNA ITS中部分核酸片段，检测采集的蚤类是否感染巴尔通体。结果共采集251只寄生蚤，包括猫栉首蚤、人蚤、缓慢细蚤等7个常见蚤种，从1组猫栉首蚤和1组缓慢细蚤中扩增出目标带，证实有巴尔通体感染。结论猫栉首蚤和缓慢细蚤能够感染巴尔通体，是该种病原体的潜在传播媒介，间接表明当地家猫和鼠类动物存在巴尔通体感染。     

Flea-borne rickettsioses: ecologic considerations.

Ecologic and economic factors, as well as changes in human behavior, have resulted in the emergence of new and the reemergence of existing but forgotten infectious diseases during the past 20 years. Flea-borne disease organisms (e.g., Yersinia pestis, Rickettsia typhi, R. felis, and Bartonella henselae) are widely distributed throughout the world in endemic-disease foci, where components of the enzootic cycle are present. However, flea-borne diseases could reemerge in epidemic form because of changes in vector-host ecology due to environmental and human behavior modification. The changing ecology of murine typhus in southern California and Texas over the past 30 years is a good example of urban and suburban expansion affecting infectious disease outbreaks. In these areas, the classic rat-flea-rat cycle of R. typhi has been replaced by a peridomestic animal cycle involving, e.g., free-ranging cats, dogs, and opossums and their fleas. In addition to the vector-host components of the murine typhus cycle, we have uncovered a second typhuslike rickettsia, R. felis. This agent was identified from the blood of a hospitalized febrile patient and from opossums and their fleas. We reviewed the ecology of R. typhi and R. felis and present recent data relevant to the vector biology, immunology, and molecular characterization and phylogeny of flea-borne rickettsioses.     

Rickettsia felis in Ctenocephalides spp. fleas, Brazil

In June 2000, suspected cases of Brazilian spotted fever (BSF) occurred in Coronel Fabriciano Municipality, Minas Gerais State, Brazil. Pooled fleas collected near two fatal cases contained rickettsial DNA. The nucleotide sequence alignment of the 391-bp segment of the 17-kDa protein gene showed that the products were identical to each other and to the R. felis 17-kDa gene, confirming circulation of R. felis in Brazil.     

Rickettsia slovaca Infection in Humans,Portugal

Fifteen years after the initial detection of Rickettsia slovaca in ticks in Portugal, 3 autochthonous cases of R. slovaca infection were diagnosed in humans. All patients had an eschar on the scalp and lymphadenopathy; 2 patients had facial edema. R. slovaca infection was confirmed by serologic testing, culture, and PCR.     

Serosurvey of Rickettsia spp. in dogs and humans from an endemic area for Brazilian spotted fever in the State of São Paulo, Brazil

The present study provides a rickettsial serosurvey in 25 dogs and 35 humans in an endemic area for Brazilian spotted fever in the State of S?o Paulo, where the tick Amblyomma aureolatum is the main vector. Testing canine and human sera by indirect immunofluorescence against four Rickettsia antigens (R. rickettsii, R. parkeri, R. felis and R. bellii) showed that 16 (64%) of canine sera and 1 (2.8%) of human sera reacted to at least one of these rickettsial antigens with titers >0r= 64. Seven canine sera and the single reactive human serum showed titers to R. rickettsii at least four times those of any of the other three antigens. The antibody titers in these 7 animals and 1 human were attributed to stimulation by R. rickettsii infection. No positive canine or human serum was attributed to stimulation by R. parkeri, R. felis, or R. bellii. Our serological results showed that dogs are important sentinels for the presence of R. rickettsii in areas where the tick A. aureolatum is the main vector of Brazilian spotted fever.     

Bartonella spp. in pets and effect on human health

Among the many mammals infected with Bartonella spp., pets represent a large reservoir for human infection because most Bartonella spp. infecting them are zoonotic. Cats are the main reservoir for Bartonella henselae, B. clarridgeiae, and B. koehlerae. Dogs can be infected with B. vinsonii subsp. berkhoffii, B. henselae, B. clarridgeiae, B. washoensis, B. elizabethae, and B. quintana. The role of dogs as an important reservoir of Bartonella spp. is less clear than for cats because domestic dogs are more likely to be accidental hosts, at least in nontropical regions. Nevertheless, dogs are excellent sentinels for human infections because a similar disease spectrum develops in dogs. Transmission of B. henselae by cat fleas is better understood, although new potential vectors (ticks and biting flies) have been identified. We review current knowledge on the etiologic agents, clinical features, and epidemiologic characteristics of these emerging zoonoses.     

A flea-associated Rickettsia pathogenic for humans

A rickettsia named the ELB agent, or "Rickettsia felis," was identified by molecular biology techniques in American fleas in 1990 and later in four patients from Texas and Mexico. We attempted to isolate this rickettsia from infected fleas at various temperatures and conditions. A representative isolate of the ELB agent, the Marseille strain, was characterized and used to develop a microimmunofluorescence test that detected reactive antibodies in human sera. The ELB agent was isolated from 19 of 20 groups of polymerase chain reaction-proven infected fleas. The microimmunofluorescence results provided serologic evidence of infection by the ELB agent in four patients with fever and rash in France (2) and Brazil (2), supporting the pathogenic role of this rickettsia. Our successful isolation of this rickettsia makes it available for use in serologic tests to determine its clinical spectrum, prevalence, and distribution.     

Emerging rickettsioses of the Thai-Myanmar border

To investigate the presence of rickettsioses in rural residents of the central Thai-Myanmar border, we tested the blood of 46 patients with fever. Four patients had murine typhus, three patients had scrub typhus, and eight patients had spotted fever group rickettsioses, including the first case of Rickettsia felis infection reported in Asia.     

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.     

三峡重庆库区鼠形动物及其体表寄生蚤调查

目的 掌握三峡重庆库区鼠形动物及其体表寄生蚤种类及密度状况,为预防控制鼠、蚤传播的疾病提供依据.方法 采用夹夜法开展鼠形动物密度监测和种类调查;采用鼠笼法捕活鼠麻醉后梳检体表寄生蚤查染蚤情况.结果 2009-2010年三峡库区重庆段平均鼠密度为1.58％,其中室内鼠密度为1.56％,室外为1.60％;捕获鼠形动物2315只,隶属于2目2科11种,四川短尾鼩、小家鼠和褐家鼠为优势种类,分别占捕获总数的38.75％ 、25.14％和19.27％.鼠体平均染蚤率为6.74％;总蚤指数为0.29;共检获鼠蚤5种,分别为缓慢细蚤(占79.16％)、印鼠客蚤(占1.08％)、不等单蚤(占2.54％)、偏远古蚤(占8.90％)和猫栉首蚤(占8.32％).结论 三峡重庆库区存在鼠疫、钩端螺旋体病和肾综合征出血热的重要储存宿主鼠种及鼠疫重要传播媒介印鼠客蚤;鼠形动物结构较为丰富,但鼠密度、鼠体染蚤率和染蚤指数较低.     

Mass flea outbreak at a child care facility: case report.

Cat fleas, Ctenocephalides felis Bouchet, were collected at a Mississippi child care facility after reports of large numbers of adult fleas occurring on children and personnel. One building yielded 161 (99 percent) of the fleas collected. Urticarial lesions due to flea bites occurred on the legs of six children. Flea presence was due to cats occupying the crawl space. Fleas were eradicated by eliminating entry of cats and using residual insecticides throughout the facility.     

Rickettsia felis in Fleas, Germany

Among 310 fleas collected from dogs and cats in Germany, Rickettsia felis was detected in all specimens (34) of Archaeopsylla erinacei (hedgehog flea) and in 9% (24/226) of Ctenocephalides felis felis (cat flea). R. helvetica was detected in 1 Ceratophyllus gallinae (hen flea).     

Baylisascaris procyonis in the metropolitan Atlanta area

Baylisascaris procyonis, the raccoon roundworm responsible for fatal larva migrans in humans, has long been thought to be absent from many regions in the southeastern United States. During spring 2002, 11 (22%) of 50 raccoons trapped in DeKalb County, Georgia, had B. procyonis infection. The increasing number of cases highlight this emerging zoonotic infection.