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 felis as emergent global threat for humans

Rickettsia felis is an emergent pathogen belonging to transitional group rickettsiae. First described in 1990, R. felis infections have been reported to occur worldwide in fleas, mammals, and humans. Because clinical signs of the illness are similar to those of murine typhus and other febrile illnesses such as dengue, the infection in humans is likely underestimated. R. felis has been found throughout the world in several types of ectoparasites; cat fleas appear to be the most common vectors. R. felis infection should be considered an emergent threat to human health.     

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).     

Spotted fever group and typhus group rickettsioses in humans, South Korea

The presence of the nucleic acid of the spotted fever group (SPG) and typhus group (TG) rickettsiae was investigated in 200 serum specimens seropositive for SFG rickettsiae by multiplex-nested polymerase chain reaction with primers derived from the rickettsial outer membrane protein B gene. The DNA of SFG, TG, or both rickettsiae was amplified in the 24 serum specimens, and sequence analysis showed Rickettsia conorii, R. japonica, and R. felis in the specimens. R. conorii and R. typhi were found in 7 serum specimens, which indicated the possibility of dual infection in these patients. These findings suggest that several kinds of rickettsial diseases, including boutonneuse fever, rickettsialpox, R. felis infection, and Japanese spotted fever, as well as scrub typhus and murine typhus, are occurring in Korea.     

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.     

Rickettsial infections and fever, Vientiane, Laos

Rickettsial diseases have not been described previously from Laos, but in a prospective study, acute rickettsial infection was identified as the cause of fever in 115 (27%) of 427 adults with negative blood cultures admitted to Mahosot Hospital in Vientiane, Laos. The organisms identified by serologic analysis were Orientia tsutsugamushi (14.8%), Rickettsia typhi (9.6%), and spotted fever group rickettsia (2.6% [8 R. helvetica, 1 R. felis, 1 R. conorii subsp. indica, and 1 Rickettsia "AT1"]). Patients with murine typhus had a lower frequency of peripheral lymphadenopathy than those with scrub typhus (3% vs. 46%, p<0.001). Rickettsioses are an underrecognized cause of undifferentiated febrile illnesses among adults in Laos. This finding has implications for the local empiric treatment of fever.     

Spotted fever and murine typhus in the Negev desert region of Israel, 1981

During 1981, 52 cases of rickettsiosis caused by the spotted fever group of rickettsiae were reported in a population of 250 000 living in the Negev desert region of Israel. Retrospectively, at least 5 of these cases were serologically shown to have been caused by Rickettsia typhi, the agent of murine typhus. Most cases of rickettsial disease occurred in the summer months and one half of all cases occurred in children aged 9 years or less. While the specificity of a physician''s diagnosis of the rickettsial diseases appears to be high (i.e., few cases of other diseases are misdiagnosed as either spotted fever or murine typhus), the sensitivity of the physician''s diagnosis may be lower (i.e., many cases of these diseases presenting as fevers of unknown origin are not diagnosed as rickettsial disease). These findings may also be important for other countries of the region.     

Murine Typhus in Austin,Texas, USA, 2008

In August 2008, Texas authorities and the Centers for Disease Control and Prevention investigated reports of increased numbers of febrile rash illnesses in Austin to confirm the causative agent as Rickettsia typhi, to assess the outbreak magnitude and illness severity, and to identify potential animal reservoirs and peridomestic factors that may have contributed to disease emergence. Thirty-three human cases of confirmed murine typhus were identified. Illness onset was reported from March to October. No patients died, but 23 (70%) were hospitalized. The case-patients clustered geographically in central Austin; 12 (36%) resided in a single ZIP code area. Specimens from wildlife and domestic animals near case-patient homes were assessed; 18% of cats, 44% of dogs, and 71% of opossums had antibodies reactive to R. typhi. No evidence of R. typhi was detected in the whole blood, tissue, or arthropod specimens tested. These findings suggest that an R. typhi cycle involving opossums and domestic animals may be present in Austin.     

Murine typhus with renal involvement in Canary Islands, Spain

Murine typhus and "murine-typhus-like" disease are reemerging infectious diseases. In Canary Islands (Spain), a rather distinct clinical pattern characterized by higher incidence of complications, especially renal damage (including acute failure and urinalysis abnormalities), is apparent and highly suggestive. It could be related to different strains of Rickettsia typhi or other cross-reactive species.     

Serosurvey of wild rodents for Rickettsioses (spotted fever, murine typhus and Q fever) in Java Island, Indonesia

The prevalence of antibodies against spotted fever group rickettsia (SFGR), murine typhus and Q fever were investigated in wild rats captured in Indonesia. Sera of 327 rats were collected from Jakarta and Boyolali on Java Island. The prevalences of antibodies against SFGR and murine typhus were 128 (39.1%) and 48 (14.7%), respectively. Antibodies against Q fever were not detected in these serum samples. Antibodies against SFGR were found in all species of rats (20.8–51.9%). The antibody positive rate against murine typhus in Rattus norvegicus (38.0%) was significantly higher than that in other rat species (0–4.8%, p < 0.01). The antibody positive rates against SFGR and murine typhus in rats captured in Jakarta were significantly higher than those in rats captured in Boyolali (p < 0.01). In this survey, all species of rats had antibodies against SFGR, indicating that the 4 species of tested rats (R. norvegicus, R. rattus, R. exulans, R. tiomanicus) were infected with SFGR and that SFGR may infest the whole of Java Island. Most of the rats that were antibody-positive against murine typhus were captured in Jakarta. Therefore, R. norvegicus and R. rattus are likely to be important hosts of murine typhus in Jakarta. The antibody-positive rates against SFGR and murine typhus in rats captured in the dry season were significantly higher than those in rats captured in the rainy season. This may coincide with the active periods of ticks and fleas in Indonesia.     

Murine typhus--Hawaii, 2002

Murine typhus, a zoonotic disease caused by Rickettsia typhi, is uncommon in the United States. Hawaii typically reports five or six cases annually; however, 47 cases were reported in 2002. This report summarizes clinical data for three of these cases and describes murine typhus activity in Hawaii during 2002 and control efforts of the Hawaii Department of Health (HDH). The high number of reported cases in 2002 underscores the need for community education to prevent murine typhus and an assessment of environmental factors that might contribute to local disease transmission.     

我国小兽与自然疫源性疾病关系研究概况

小型兽类可保存或传播自然疫源性疾病有数十种,主要有鼠疫、鼠型斑疹伤寒、肾综合征出血热、钩端螺旋体病、恙虫病等。其体外寄生虫如蜱、螨、跳蚤、虱等是传播多种疾病的媒介昆虫。由于种类多,分布广,迁移性较小,不同种类的组成及空间分布特征又多与地理环境、气候条件、生态适应性能力和多种疾病的关系密切,因此对小型兽类与疾病关系的调查研究具有重要意义。该文介绍了我国目前小型兽类与重要或常见自然疫源性疾病关系的研究概况,为人畜共患传染病的研究和防治工作提供参考。     

Knowledge-based patient screening for rare and emerging infectious/parasitic diseases: a case study of brucellosis and murine typhus.

Many infectious and parasitic diseases, especially those newly emerging or reemerging, present a difficult diagnostic challenge because of their obscurity and low incidence. Important clues that could lead to an initial diagnosis are often overlooked, misinterpreted, not linked to a disease, or disregarded. We constructed a computer-based decision support system containing 223 infectious and parasitic diseases and used it to conduct a historical intervention study based on field investigation records of 200 cases of human brucellosis and 96 cases of murine typhus that occurred in Texas from 1980 through 1989. Knowledge-based screening showed that the average number of days from the initial patient visit to the time of correct diagnosis was significantly reduced (brucellosis-from 17.9 to 4.5 days, p = 0.0001, murine typhus-from 11.5 to 8.6 days, p = 0.001). This study demonstrates the potential value of knowledge-based patient screening for rare infectious and parasitic diseases.     

Epidemiology of rickettsial diseases

Rickettsial diseases have a diversity of epidemiologic characteristics reflective of the variety of ecologic situations in which the obligate intracellular bacteria are transmitted to humans. For the spotted fever group (SFG) rickettsiae, Rickettsia typhi. R. tsutsugamushi, Coxiella burnetii, and the human ehrlichial agent, humans are a dead-end host who plays no role in the maintenance of the organism in nature. All rickettsioses exist as zoonoses. Moreover, all rickettsiae are found in infected arthopods, which generally serve as the natural hosts and can transmit the infection to the next generation of ticks, mites, chiggers, or fleas. From our anthropocentric viewpoint, Q fever aerosol infection from parturient animals and Brill-Zinsser disease ignited epidemics of louse-borne epidemic typhus are exceptions. However, silent cycles of C. burnetii in ticks and R. prowazekii in the flying squirrel flea may have maintained these agents in transovarial or enzootic cycles for eons before humans and their domestic animals arrived on the scene. Thus, the epidemiology of rickettsial diseases must be recognized as an unfortunate aberration of the rickettsial economy.Several excellent reviews of rickettsial ecology contain a wealth of useful information (2, 8, 55, 70, 84).Presented at the 4th International Symposium on Riskettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990.     

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.     

Serological and blood culture investigations of Nepalese fever patients

Serological testing of paired (i.e. admission and convalescent) sera from 103 fever patients in Kathmandu, Nepal, was performed to estimate the prevalence rates of scrub typhus, murine typhus, Leptospira and dengue virus antibodies and to determine their role in the cause of active infections. Blood cultures from 15 patients grew Salmonella enterica serovar Typhi, 8 grew S. Paratyphi A and 6 grew other bacteria. Diagnostic antibody levels were detected against murine typhus (27/103; 26%), scrub typhus (23/103; 22%), Leptospira (10/103; 10%) and dengue virus (8/103; 8%). Nineteen patients (18%) had diagnostically raised antibodies to more than one infectious agent. Seven S. Typhi (7/15; 47%) and two S. Paratyphi A (2/8; 25%) patients had significant scrub typhus, murine typhus, Leptospira or dengue virus IgM antibody titres. This study confirms the presence of leptospiral, rickettsial and dengue infections in Kathmandu as well as evidence for mixed infections with S. Typhi and Orientia tsutsugamushi or Rickettsia typhi. These infections should be kept in mind when considering the differential diagnoses of fever and empirical treatment options in Nepal. Many patients demonstrated static IgM antibody results between paired serum collections, suggesting recent rather than acutely active infections.     

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.     

云南省玉溪市红塔区鼠型斑疹伤寒病原及血清流行病学调查

目的明确玉溪市红塔区是否为鼠型斑疹伤寒疫源地。方法采用微量室温补体结合法，对红塔区人群和鼠类进行鼠型斑疹伤寒（莫氏）立克次体血清抗体检测，用鼠、鼠体外寄生节肢动物标本接种豚鼠进行病原体分离，并调查鼠密度和鼠蚤指数。结果调查的7镇14个调查点人群血清抗体均检出阳性，总阳性率28．92％（96／332），几何平均滴度（GMT）为10．83，其中发热患者和健康人群抗体阳性率分别为31．86％（72／226）和22．64％（24／106）；男女阳性率分别为26．71％（43／161）、30．99％（53／171），性别间差异无统计学意义（P〉0，05）；年龄组阳性率分别为0-6岁29．63％（8／27）、7-18岁18．06％（13／72）、19-39岁39．62％（42／106）、40-59岁27．50％（22／80）、60岁以上23．40％（11／47），各年龄组差异有统计学意义（P〈0．05）；10个调查点捕获的鼠类均检出抗体，阳性率为44．95％（89／198），GMT为30．30；从11组鼠类标本中分离到5株莫氏立克次体，从6组蚤类标本中分离到3株莫氏立克次体，病原体分离率为44．44％（8／18），其中鼠类为45．45％（5／11）、蚤类为50．00％（3／6）；1组螨类标本接种豚鼠未引起豚鼠发病；确诊1例鼠型斑疹伤寒病例；褐家鼠和黄胸鼠占捕鼠总数的99．49％（197／198）、印鼠客蚤占捡蚤总数的74．26％（303／408），鼠蚤指数为2．06，鼠密度为11．13％。结论红塔区人群和鼠类中存在鼠型斑疹伤寒，且处在较高感染水平，可认定该区为鼠型斑疹伤寒疫源地。