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Infectious Disease Clinics of North... Mar 2019Rickettsia are small, obligately intracellular, gram-negative bacilli. They are distributed among a variety of hematophagous arthropod vectors and cause illness... (Review)
Review
Rickettsia are small, obligately intracellular, gram-negative bacilli. They are distributed among a variety of hematophagous arthropod vectors and cause illness throughout the world. Rickettsioses present as an acute undifferentiated febrile illness and are often accompanied by headache, myalgias, and malaise. Cutaneous manifestations include rash and eschar, which both occur at varying incidence depending on the infecting species. Serology is the mainstay of diagnosis, and the indirect immunofluorescence assay is the test of choice. Reactive antibodies are seldom present during early illness, so testing should be performed on both acute-phase and convalescent-phase sera. Doxycycline is the treatment of choice.
Topics: Animals; Anti-Bacterial Agents; Arthropod Vectors; Doxycycline; Humans; Rickettsia Infections; Rocky Mountain Spotted Fever
PubMed: 30712763
DOI: 10.1016/j.idc.2018.10.010 -
Proceedings (Baylor University. Medical... 2022Murine typhus is a rare condition caused by the gram-negative bacterium which classically presents with the triad of fever, rash, and headache. Herein we report a rare...
Murine typhus is a rare condition caused by the gram-negative bacterium which classically presents with the triad of fever, rash, and headache. Herein we report a rare presentation of murine typhus in an adult who presented predominantly with fever and gastrointestinal symptoms. Initial imaging showed cardiomegaly and hepatosplenomegaly, which led to further workup revealing rickettsial disease. Although this illness is considered a rare diagnosis in the emergency department, every person with a pet that might have fleas is susceptible to it.
PubMed: 35991722
DOI: 10.1080/08998280.2022.2078640 -
Microbes and Infection 2015Bacteria of the genera Rickettsia and Orientia (family rickettsiaceae, order rickettsiales) cause rickettsioses worldwide, and are transmitted by lice, fleas, ticks and... (Review)
Review
Bacteria of the genera Rickettsia and Orientia (family rickettsiaceae, order rickettsiales) cause rickettsioses worldwide, and are transmitted by lice, fleas, ticks and mites. In Europe, only Rickettsia spp. cause rickettsioses. With improvement of hygiene, the risk of louse-borne rickettsiosis (epidemic typhus) is low in Europe. Nevertheless, recrudescent form of Rickettsia prowazekii infection persists. There could be an epidemic typhus outbreak if a body lice epidemic occurs under unfavorable sanitary conditions. In Europe, endemic typhus or Rickettsia typhi infection, transmitted by rats and fleas, causes febrile illness. At the beginning of this century, flea-borne spotted fever cases caused by Rickettsia felis were diagnosed. Flea-borne rickettsiosis should be suspected after flea bites if fever, with or without rash, is developed. Tick-borne rickettsioses are the main source of rickettsia infections in Europe. Apart from Rickettsia conorii, the Mediterranean Spotted Fever (MSF) agent, other Rickettsia spp. cause MSF-like: Rickettsia helvetica, Rickettsia monacensis, Rickettsia massiliae or Rickettsia aeschlimannii. In the 1990s, two 'new' rickettsioses were diagnosed: Lymphangitis Associated Rickettsiosis (LAR) caused by Rickettsia sibirica mongolitimonae, and Tick-Borne Lymphadenopathy/Dermacentor-Borne-Necrosis-Erythema-Lymphadenopathy/Scalp Eschar Neck Lymphadenopathy (TIBOLA/DEBONEL/SENLAT), caused by Rickettsia slovaca, Candidatus Rickettsia rioja and Rickettsia raoultii. Lastly, European reports about mite-borne rickettsiosis are scarce.
Topics: Animals; Arthropods; Europe; Humans; Orientia tsutsugamushi; Rickettsia; Rickettsia Infections; Scrub Typhus
PubMed: 26384814
DOI: 10.1016/j.micinf.2015.09.009 -
Environmental Microbiology Dec 2018Bacterial signal transduction systems are responsible for sensing environmental cues and adjusting the cellular behaviour and/or metabolism in response to these cues.... (Review)
Review
Bacterial signal transduction systems are responsible for sensing environmental cues and adjusting the cellular behaviour and/or metabolism in response to these cues. They also monitor the intracellular conditions and the status of the cell envelope and the cytoplasmic membrane and trigger various stress responses to counteract adverse changes. This surveillance involves several classes of sensor proteins: histidine kinases; chemoreceptors; membrane components of the sugar phosphotransferase system; adenylate, diadenylate and diguanylate cyclases and certain cAMP, c-di-AMP and c-di-GMP phosphodiesterases; extracytoplasmic function sigma factors and Ser/Thr/Tyr protein kinases and phosphoprotein phosphatases. We have compiled a detailed listing of sensor proteins that are encoded in the genomes of Escherichia coli, Bacillus subtilis and 10 widespread pathogens: Chlamydia trachomatis, Haemophilus influenzae, Helicobacter pylori, Mycobacterium tuberculosis, Mycoplasma pneumoniae, Neisseria gonorrhoeae, Porphyromonas gingivalis, Rickettsia typhi, Streptococcus pyogenes and Treponema pallidum, and checked what, if anything, is known about their functions. This listing shows significant gaps in the understanding of which environmental and intracellular cues are perceived by these bacteria and which cellular responses are triggered by the changes in the respective parameters. A better understanding of bacterial preferences may suggest new ways to modulate the expression of virulence factors and therefore decrease the reliance on antibiotics to fight infection.
Topics: Bacteria; Bacterial Physiological Phenomena; Environmental Microbiology; Gene Expression Regulation, Bacterial; Signal Transduction
PubMed: 30187651
DOI: 10.1111/1462-2920.14398 -
The American Journal of Tropical... Jan 2017Rickettsia typhi and Rickettsia felis are flea-borne rickettsiae that are distributed throughout the world. This mini-review outlines the ecology and epidemiology of... (Review)
Review
Rickettsia typhi and Rickettsia felis are flea-borne rickettsiae that are distributed throughout the world. This mini-review outlines the ecology and epidemiology of flea-borne rickettsioses; highlights important clinical, diagnostic, and therapeutic considerations; and discusses areas of uncertainty regarding Rickettsia felis and other rickettsiae harbored by fleas.
Topics: Animals; Ectoparasitic Infestations; Humans; Rickettsia Infections; Siphonaptera
PubMed: 27799640
DOI: 10.4269/ajtmh.16-0537 -
Research and Reports in Tropical... 2021Murine typhus and flea-borne spotted fever are undifferentiated febrile illnesses caused by and , respectively. These organisms are small obligately intracellular... (Review)
Review
Murine typhus and flea-borne spotted fever are undifferentiated febrile illnesses caused by and , respectively. These organisms are small obligately intracellular bacteria and are transmitted to humans by fleas. Murine typhus is endemic to coastal areas of the tropics and subtropics (especially port cities), where rats are the primary mammalian host and rat fleas () are the vector. In the United States, a cycle of transmission involving opossums and cat fleas () are the presumed reservoir and vector, respectively. The incidence and distribution of murine typhus appear to be increasing in endemic areas of the US. has also been reported throughout the world and is found within the ubiquitous cat flea. Flea-borne rickettsioses manifest as an undifferentiated febrile illness. Headache, malaise, and myalgia are frequent symptoms that accompany fever. The incidence of rash is variable, so its absence should not dissuade the clinician to consider a rickettsial illness as part of the differential diagnosis. When present, the rash is usually macular or papular. Although not a feature of murine typhus, eschar has been found in 12% of those with flea-borne spotted fever. Confirmatory laboratory diagnosis is usually obtained by serology; the indirect immunofluorescence assay is the serologic test of choice. Antibodies are seldom present during the first few days of illness. Thus, the diagnosis requires acute- and convalescent-phase specimens to document seroconversion or a four-fold increase in antibody titer. Since laboratory diagnosis is usually retrospective, when a flea-borne rickettsiosis is considered, empiric treatment should be initiated. The treatment of choice for both children and adults is doxycycline, which results in a swift and effective response. The following review is aimed to summarize the key clinical, epidemiological, ecological, diagnostic, and treatment aspects of flea-borne rickettsioses.
PubMed: 33574726
DOI: 10.2147/RRTM.S274724 -
PLoS Neglected Tropical Diseases May 2022Murine typhus, which is caused by Rickettsia typhi, has a wide range of clinical manifestations. It has a low mortality rate but may result in meningoencephalitis and...
Murine typhus, which is caused by Rickettsia typhi, has a wide range of clinical manifestations. It has a low mortality rate but may result in meningoencephalitis and interstitial pneumonia in severe cases. Comparisons of complete genome sequences of R. typhi isolates from North Carolina, USA (Wilmington), Myanmar (B9991PP), and Thailand (TH1527) identified only 26 single nucleotide polymorphism (SNP) and 7 insertion-deletion (INDEL) sites in these highly syntenic genomes. Assays were developed to further define the distribution of these variant sites among 15 additional isolates of R. typhi with different histories from Asia, the USA, and Africa. Mismatch amplification mutation assays (MAMA) were validated for 22 SNP sites, while the 7 INDEL sites were analyzed directly on agarose gels. Six SNP types, 9 INDEL types, 11 total types were identified among these 18 isolates. Replicate DNA samples as well as comparisons of isolates with different passage and source histories gave consistent genetic typing profiles. Comparison of the SNP and INDEL markers to R. typhi's nearest neighbor Rickettsia prowazekii demonstrated that the majority of the SNPs represent intra-species variation that arose post divergence of these two species while several INDEL sites also exhibited intraspecies variability among the R. prowazekii genomes that have been completely sequenced. The assays for the presence of these SNP and INDEL sites, particularly the latter, comprise a low technology gel method for consistently distinguishing R. typhi and R. prowazekii as well as for differentiating genetic types of R. typhi.
Topics: Animals; Mice; Rickettsia; Rickettsia prowazekii; Rickettsia typhi; Sequence Analysis, DNA; Thailand; Typhus, Endemic Flea-Borne
PubMed: 35639778
DOI: 10.1371/journal.pntd.0010354 -
Research and Reports in Tropical... 2018In this paper, we present a historical review of rickettsiosis in Central America and also the most recent findings of in ectoparasites. All countries of Central... (Review)
Review
In this paper, we present a historical review of rickettsiosis in Central America and also the most recent findings of in ectoparasites. All countries of Central America have records of rickettsiosis. Regarding the typhus group rickettsioses, there is clinical or serological evidence of in Guatemala, in Panama, Guatemala, and Costa Rica and unidentified species of the typhus group in El Salvador. Concerning spotted fever group rickettsiosis, there is serological evidence of infection by in Costa Rica and confirmed cases involving in Panama and Costa Rica. There are also reports of spotted fever group rickettsiosis in acute patients from Guatemala, Honduras, and Nicaragua. Serological studies in Central America show reactivity of , , , , and in domestic and wild mammals. Eight species of have been detected in ectoparasites from Central America: (or very similar), , , , , , , and , in addition to undescribed strains such as Atlantic Rainforest, Colombianensi, IbR/CRC, Barva, Aragaoi, and "Rickettsia nicoyana;" the latter being the only one associated with Argasidae (). is the most common species in Central America, seeing as it has been reported in 10 species of ticks and one of fleas in five of the seven countries of the region. In this study, we demonstrate that the genus is widely distributed in Central America and that rickettsiosis could be an underestimated problem in the absence of greater diagnostic efforts in undetermined febrile cases.
PubMed: 30050361
DOI: 10.2147/RRTM.S160951 -
Emerging Infectious Diseases Nov 2023Murine typhus is a febrile, fleaborne disease caused by infection with Rickettsia typhi bacteria. Cases can range from mild and nonspecific to fatal. We report 2 cases...
Murine typhus is a febrile, fleaborne disease caused by infection with Rickettsia typhi bacteria. Cases can range from mild and nonspecific to fatal. We report 2 cases of murine typhus in Costa Rica, confirming the presence and circulation of R. typhi causing severe disease in the country.
Topics: Animals; Mice; Humans; Typhus, Endemic Flea-Borne; Costa Rica; Rickettsia typhi; Rickettsia
PubMed: 37877575
DOI: 10.3201/eid2911.221561