Rickettsia typhi as Cause of Fatal Encephalitic Typhus in Hospitalized Patients, Hamburg, Germany, 1940-1944.

We evaluated formalin-fixed paraffin-embedded tissue specimens from 7 patients who died with encephalitic typhus in Hamburg, Germany, during World War II. The archived specimens included only central nervous system tissues >70 years old that had been stored at room temperature. We demonstrated successful detection of Rickettsia typhi DNA by a nested qPCR specific to prsA in 2 patients. These results indicate that R. typhi infections contributed to typhus outbreaks during World War II. Immunohistochemical analyses of brain tissue specimens of R. typhi DNA-positive and -negative specimens showed perivascular B-cell accumulation. Around blood vessels, nodular cell accumulations consisted of CD4-positive and CD8-positive T cells and CD68-positive microglia and macrophages; neutrophils were found rarely. These findings are similar to those of previously reported R. prowazekii tissue specimen testing. Because R. typhi and R. prowazekii infections can be clinically and histopathologically similar, molecular analyses should be performed to distinguish the 2 pathogens.

Persisting Rickettsia typhi Causes Fatal Central Nervous System Inflammation.

Rickettsioses are emerging febrile diseases caused by obligate intracellular bacteria belonging to the family Rickettsiaceae. Rickettsia typhi belongs to the typhus group (TG) of this family and is the causative agent of endemic typhus, a disease that can be fatal. In the present study, we analyzed the course of R. typhi infection in C57BL/6 RAG1(-/-) mice. Although these mice lack adaptive immunity, they developed only mild and temporary symptoms of disease and survived R. typhi infection for a long period of time. To our surprise, 3 to 4 months after infection, C57BL/6 RAG1(-/-) mice suddenly developed lethal neurological disorders. Analysis of these mice at the time of death revealed high bacterial loads, predominantly in the brain. This was accompanied by a massive expansion of microglia and by neuronal cell death. Furthermore, high numbers of infiltrating CD11b(+) macrophages were detectable in the brain. In contrast to the microglia, these cells harbored R. typhi and showed an inflammatory phenotype, as indicated by inducible nitric oxide synthase (iNOS) expression, which was not observed in the periphery. Having shown that R. typhi persists in immunocompromised mice, we finally asked whether the bacteria are also able to persist in resistant C57BL/6 and BALB/c wild-type mice. Indeed, R. typhi could be recultivated from lung, spleen, and brain tissues from both strains even up to 1 year after infection. This is the first report demonstrating persistence and reappearance of R. typhi, mainly restricted to the central nervous system in immunocompromised mice.

Rickettsia typhi possesses phospholipase A2 enzymes that are involved in infection of host cells.

The long-standing proposal that phospholipase A2 (PLA2) enzymes are involved in rickettsial infection of host cells has been given support by the recent characterization of a patatin phospholipase (Pat2) with PLA2 activity from the pathogens Rickettsia prowazekii and R. typhi. However, pat2 is not encoded in all Rickettsia genomes; yet another uncharacterized patatin (Pat1) is indeed ubiquitous. Here, evolutionary analysis of both patatins across 46 Rickettsia genomes revealed 1) pat1 and pat2 loci are syntenic across all genomes, 2) both Pat1 and Pat2 do not contain predicted Sec-dependent signal sequences, 3) pat2 has been pseudogenized multiple times in rickettsial evolution, and 4) ubiquitous pat1 forms two divergent groups (pat1A and pat1B) with strong evidence for recombination between pat1B and plasmid-encoded homologs. In light of these findings, we extended the characterization of R. typhi Pat1 and Pat2 proteins and determined their role in the infection process. As previously demonstrated for Pat2, we determined that 1) Pat1 is expressed and secreted into the host cytoplasm during R. typhi infection, 2) expression of recombinant Pat1 is cytotoxic to yeast cells, 3) recombinant Pat1 possesses PLA2 activity that requires a host cofactor, and 4) both Pat1 cytotoxicity and PLA2 activity were reduced by PLA2 inhibitors and abolished by site-directed mutagenesis of catalytic Ser/Asp residues. To ascertain the role of Pat1 and Pat2 in R. typhi infection, antibodies to both proteins were used to pretreat rickettsiae. Subsequent invasion and plaque assays both indicated a significant decrease in R. typhi infection compared to that by pre-immune IgG. Furthermore, antibody-pretreatment of R. typhi blocked/delayed phagosomal escapes. Together, these data suggest both enzymes are involved early in the infection process. Collectively, our study suggests that R. typhi utilizes two evolutionary divergent patatin phospholipases to support its intracellular life cycle, a mechanism distinguishing it from other rickettsial species.

Dose-response model of murine typhus (Rickettsia typhi): time post inoculation and host age dependency analysis.

BACKGROUND: Rickettsia typhi (R. mooseri) is the causative agent of murine typhus. It is one of the most widely distributed flea-borne diseases with a relatively mild febrile initial illness with six to 14 days of incubation period. The bacterium is gram negative and an obligate intracellular pathogen. The disease is transmitted to humans and vertebrate host through fleabites or via contact with infected feces. This paper develops dose-response models of different routes of exposure for typhus in rodents. METHODS: Data from published articles were analyzed using parametric dose-response relationship models. Dose-response relationships were fit to data using the method of maximum likelihood estimation (MLE). RESULTS: Dose-response models quantifying the effects of different ages of rats and time post inoculation in BALB/c mice were analyzed in the study. Both the adult rats (inoculated intradermally) and newborn rats (inoculated subcutaneously) were best fit by exponential models and both distributions could be described by a single dose-response relationship. The BALB/C mice inoculated subcutaneously were best fit by Beta-Poisson models. The time post inoculation analysis showed that there was a definite time and response relationship existed in this case. CONCLUSIONS: Intradermally or subcutaneously inoculated rats (adult and newborn) models suggest that less than 1 plaque-forming unit (PFU) (1.33 to 0.38 in 95% confidence limits) of the pathogen is enough to seroconvert 50% of the exposed population on average. For the BALB/c mouse time post inoculation model, an average dose of 0.28 plaque-forming units (PFU) (0.75 to 0.11 in 95% confidence limits) will seroconvert 50% of the exposed mice.

Murine typhus returns to New South Wales: a case of isolated meningoencephalitis with raised intracranial pressure.

Murine typhus (MT) occurs worldwide, but, in Australia, is only regularly diagnosed in south-west Western Australia. Meningoencephalitis is an uncommon complication of MT, often accompanied by rash or systemic involvement. We report a case of MT presenting exclusively with meningoencephalitis, raised intracranial pressure, papilloedema and bilateral 6th cranial nerve palsies. MT should be considered in patients with "aseptic" meningitis or meningoencephalitis, even in the absence of other typical features of a typhus-like illness.

[Spotted typhoid fever in the Iceland of the sagas?]. / Flekktyfus på sagatidens Island?

In spite of Iceland's geographically isolated position, epidemics of infectious diseases obviously occurred from the very beginning, brought to the island by the first Norwegian settlers and their cattle in the 9th century. People living close together in small farming communities were of course exposed to infection, which must have been common in the narrow Icelandic farmhouses. People had very little understanding or knowledge of protection against contagion, and the whole family, often sleeping together in the same bed, would be an easy prey to contagion. Epidemics were often regarded as caused by supernatural, evil forces, and two of the Icelandic sagas in particular - Grette's Saga and the Eyrbyggja Saga - give an account that may well be the first ever description of an epidemic, perhaps of spotted typhoid fever, in the history of medicine. In these sagas, the accounts are presented as ghost stories. The disease is caused by the faeces of infected lice, and leads to severe haemorrages in the skin and intestine. It also affects the central nervous system and has a high mortality rate.

Case Report: Renal Failure due to Focal Segmental Glomerulosclerosis in a Patient with Murine Typhus.

Murine typhus is a flea-borne rickettsiosis caused by Rickettsia typhi. When severe, endothelial dysfunction can lead to acute kidney injury secondary to prerenal azotemia or acute tubular necrosis. Here, we describe an unusual cause of kidney injury during the course of murine typhus-focal segmental glomerulosclerosis.

Outbreak of Rickettsia typhi infection - Austin, Texas, 2008.

Murine typhus is a fleaborne rickettsial disease caused by the organism Rickettsia typhi. Symptoms include fever, headache, chills, vomiting, nausea, myalgia, and rash. Although murine typhus is endemic in southern Texas, only two cases had been reported during the past 10 years from Austin, located in central Texas. On August 8, 2008, the Austin/Travis County Department of Health and Human Services (ATCDHHS) contacted the Texas Department of State Health Services (TDSHS) concerning a cluster of 14 illnesses with serologic findings indicative of murine typhus. On August 12, 2008, TDSHS initiated an investigation with assistance from CDC to characterize the magnitude of the outbreak and assess potential animal reservoirs and peridomestic factors that might have contributed to disease. This report summarizes the clinical and environmental findings of that investigation. Thirty-three confirmed cases involved illness comparable to that associated with previous outbreaks of murine typhus. Illness ranged from mild to severe, with 73% of patients requiring hospitalization. Delayed diagnosis and administration of no or inappropriate antibiotics might have contributed to illness severity. Environmental investigation suggested that opossums and domestic animals likely played a role in the maintenance and spread of R. typhi; however, their precise role in the outbreak has not been determined. These findings underscore the need to increase awareness of murine typhus and communicate appropriate treatment and prevention measures through the distribution of typhus alerts before and throughout the peak vector season of March-November.

Murine Typhus with Marked Thrombocytopenia in a Child in Northern Greece and Literature Review.

We report a case of murine typhus in a 4-year-old boy living in northern Greece. Although the illness started with mild symptoms, a maculopapular rash appeared by the end of the first week of illness followed by marked thrombocytopenia. The detection of IgM antibodies against Rickettsia typhi in the patient's blood and a positive polymerase chain reaction result combined with sequencing confirmed the diagnosis of infection by Rickettsia typhi. Clinicians in northern Greece should be aware of the disease, even in cases presenting with no specific initial symptoms.

Cytotoxic effector functions of T cells are not required for protective immunity against fatal Rickettsia typhi infection in a murine model of infection: Role of TH1 and TH17 cytokines in protection and pathology.

Endemic typhus caused by Rickettsia (R.) typhi is an emerging febrile disease that can be fatal due to multiple organ pathology. Here we analyzed the requirements for protection against R. typhi by T cells in the CB17 SCID model of infection. BALB/c wild-type mice generate CD4+ TH1 and cytotoxic CD8+ T cells both of which are sporadically reactivated in persistent infection. Either adoptively transferred CD8+ or CD4+ T cells protected R. typhi-infected CB17 SCID mice from death and provided long-term control. CD8+ T cells lacking either IFNγ or Perforin were still protective, demonstrating that the cytotoxic function of CD8+ T cells is not essential for protection. Immune wild-type CD4+ T cells produced high amounts of IFNγ, induced the release of nitric oxide in R. typhi-infected macrophages and inhibited bacterial growth in vitro via IFNγ and TNFα. However, adoptive transfer of CD4+IFNγ-/- T cells still protected 30-90% of R. typhi-infected CB17 SCID mice. These cells acquired a TH17 phenotype, producing high amounts of IL-17A and IL-22 in addition to TNFα, and inhibited bacterial growth in vitro. Surprisingly, the neutralization of either TNFα or IL-17A in CD4+IFNγ-/- T cell recipient mice did not alter bacterial elimination by these cells in vivo, led to faster recovery and enhanced survival compared to isotype-treated animals. Thus, collectively these data show that although CD4+ TH1 cells are clearly efficient in protection against R. typhi, CD4+ TH17 cells are similarly protective if the harmful effects of combined production of TNFα and IL-17A can be inhibited.

Fatal Flea-Borne Typhus in Texas: A Retrospective Case Series, 1985-2015.

AbstractFlea-borne (murine) typhus is a global rickettsiosis caused by Rickettsia typhi. Although flea-borne typhus is no longer nationally notifiable, cases are reported for surveillance purposes in a few U.S. states. The infection is typically self-limiting, but may be severe or life-threatening in some patients. We performed a retrospective review of confirmed or probable cases of fatal flea-borne typhus reported to the Texas Department of State Health Services during 1985-2015. When available, medical charts were also examined. Eleven cases of fatal flea-borne typhus were identified. The median patient age was 62 years (range, 36-84 years) and 8 (73%) were male. Patients presented most commonly with fever (100%), nausea and vomiting (55%), and rash (55%). Respiratory (55%) and neurologic (45%) manifestations were also identified frequently. Laboratory abnormalities included thrombocytopenia (82%) and elevated hepatic transaminases (63%). Flea or animal contact before illness onset was frequently reported (55%). The median time from hospitalization to administration of a tetracycline-class drug was 4 days (range, 0-5 days). The median time from symptom onset to death was 14 days (range, 1-34 days). Flea-borne typhus can be a life-threatening disease if not treated in a timely manner with appropriate tetracycline-class antibiotics. Flea-borne typhus should be considered in febrile patients with animal or flea exposure and respiratory or neurologic symptoms of unknown etiology.

Identification of factors for physicians to facilitate early differential diagnosis of scrub typhus, murine typhus, and Q fever from dengue fever in Taiwan.

BACKGROUND: Dengue fever, rickettsial diseases, and Q fever are acute febrile illnesses with similar manifestations in tropical areas. Early differential diagnosis of scrub typhus, murine typhus, and Q fever from dengue fever may be made by understanding the distinguishing clinical characteristics and the significance of demographic and weather factors. METHODS: We conducted a retrospective study to identify clinical, demographic, and meteorological characteristics of 454 dengue fever, 178 scrub typhus, 143 Q fever, and 81 murine typhus cases in three Taiwan hospitals. RESULTS: Case numbers of murine typhus and Q fever correlated significantly with temperature and rainfall; the scrub typhus case number was only significantly related with temperature. Neither temperature nor rainfall correlated with the case number of dengue fever. The rarity of dengue fever cases from January to June in Taiwan may be a helpful clue for diagnosis in the area. A male predominance was observed, as the male-to-female rate was 2.1 for murine typhus and 7.4 for Q fever. Multivariate analysis revealed the following six important factors for differentiating the rickettsial diseases and Q fever group from the dengue fever group: fever ≥8 days, alanine aminotransferase > aspartate aminotransferase, platelets >63,000/mL, C-reactive protein >31.9 mg/L, absence of bone pain, and absence of a bleeding syndrome. CONCLUSION: Understanding the rarity of dengue in the first half of a year in Taiwan and the six differentiating factors may help facilitate the early differential diagnosis of rickettsial diseases and Q fever from dengue fever, permitting early antibiotic treatment.

Molecular evidence of Rickettsia typhi infection in dogs from a rural community in Yucatán, México.

INTRODUCTION: Rickettsia typhi causes murine or endemic typhus, which is transmitted to humans primarily through flea bites contaminated with feces. Synanthropic and domestic animals also contribute to the infection cycle of R. typhi. Cases of murine typhus in humans were reported in the rural community of Bolmay, Yucatán, México, between 2007 and 2010.  OBJECTIVE: To identify the presence of R. typhi and estimate the frequency of infection in dogs from Bolmay, México, a locality with previous reports of murine typhus in humans.  MATERIALS AND METHODS: Whole blood samples were taken from 128 dogs. Total DNA was extracted for use in the polymerase chain reaction (PCR) to amplify fragments of the 17 kDa and omp B genes and confirms the presence of Rickettsia spp. The reaction products were sequenced, and alignment analysis was performed using the BLAST tool.  RESULTS: The frequency of R. typhi infection in dogs was 5.5 % (7/128). The alignment identified 99% and 100% homology to the R. typhi 17 kDa and omp B genes, respectively.  CONCLUSION: We confirmed the presence of R. typhi in dogs in the studied community but at a low frequency. However, there is potential risk of transmission to humans.

Liver Necrosis and Lethal Systemic Inflammation in a Murine Model of Rickettsia typhi Infection: Role of Neutrophils, Macrophages and NK Cells.

Rickettsia (R.) typhi is the causative agent of endemic typhus, an emerging febrile disease that is associated with complications such as pneumonia, encephalitis and liver dysfunction. To elucidate how innate immune mechanisms contribute to defense and pathology we here analyzed R. typhi infection of CB17 SCID mice that are congenic to BALB/c mice but lack adaptive immunity. CB17 SCID mice succumbed to R. typhi infection within 21 days and showed high bacterial load in spleen, brain, lung, and liver. Most evident pathological changes in R. typhi-infected CB17 SCID mice were massive liver necrosis and splenomegaly due to the disproportionate accumulation of neutrophils and macrophages (MΦ). Both neutrophils and MΦ infiltrated the liver and harbored R. typhi. Both cell populations expressed iNOS and produced reactive oxygen species (ROS) and, thus, exhibited an inflammatory and bactericidal phenotype. Surprisingly, depletion of neutrophils completely prevented liver necrosis but neither altered bacterial load nor protected CB17 SCID mice from death. Furthermore, the absence of neutrophils had no impact on the overwhelming systemic inflammatory response in these mice. This response was predominantly driven by activated MΦ and NK cells both of which expressed IFNγ and is considered as the reason of death. Finally, we observed that iNOS expression by MΦ and neutrophils did not correlate with R. typhi uptake in vivo. Moreover, we demonstrate that MΦ hardly respond to R. typhi in vitro. These findings indicate that R. typhi enters MΦ and also neutrophils unrecognized and that activation of these cells is mediated by other mechanisms in the context of tissue damage in vivo.

An Unusual Cutaneous Manifestation in a Patient with Murine Typhus.

Murine typhus is a flea-borne febrile illness caused by Rickettsia typhi. Although often accompanied by rash, an inoculation lesion has not been observed as it is with many tick- and mite-transmitted rickettsioses. We describe a patient with murine typhus and an unusual cutaneous manifestation at the site of rickettsial inoculation.

Abducens nerve palsy and meningitis by Rickettsia typhi.

Patients with rickettsial infection may present with encephalitis or meningitis but neurologic involvement is rare in murine typhus. Here, we report two patients with Rickettsia typhi meningitis who presented with cranial neuropathy, presumably caused by two distinct disease processes. Recognition of the disease manifestations is important because rickettsial infections are potentially associated with significant morbidity. Simple effective treatments are available.

Histopathology and immunohistologic demonstration of the distribution of Rickettsia typhi in fatal murine typhus.

An 81-year-old woman had chills, fever, nausea, vomiting, and epigastric pain. On day 3 she had hematuria and was treated with trimethoprim-sulfamethoxazole. On day 5 she had a cough, hypotension, anemia, azotemia, and elevated hepatic enzyme levels. Her condition deteriorated with thrombocytopenia, anuria requiring dialysis, edema, and hypoalbuminemia. Treatment with chloramphenicol and doxycycline was started on day 10. By day 11, she was in hypotensive shock; on day 12 she had seizures and died. Murine typhus was diagnosed by demonstration of antibodies to Rickettsia typhi by indirect immunofluorescence. Necropsy revealed interstitial pneumonia, pulmonary edema, hyaline membranes, alveolar hemorrhages, petechiae and vasculitis in the central nervous system, interstitial myocarditis, multifocal interstitial nephritis and hemorrhages, splenomegaly, portal triaditis, and mucosal hemorrhages in urinary tract. Immunofluorescent R. typhi were demonstrated in the lungs, brain, kidneys, liver, and heart. This unusual death occurred in an elderly patient without rash who was treated too late with antirickettsial drugs.

Liver involvement in murine typhus.

Liver involvement was retrospectively evaluated in 137 patients with murine typhus. Fifteen (10.9%) were jaundiced. One patient had been subjected to cholecystectomy after misdiagnosis of acute cholecystitis. Serum aminotransferase levels were abnormal in 48/52 measurements, and there were elevations of > 5-fold in 14 patients. Liver biopsies and/or necropsies from four jaundiced patients showed portal tract and sinusoidal infiltrates, cloudy swelling/and necrosis of the hepatocytes and occasional pseudogranuloma formation. There were striking mitoses even in the early stage, suggesting rapid hepatocellular regeneration. Haemolytic diseases (G6PD deficiency or haemoglobinopathies), alcoholism, and a second infection probably also contributed to the pathogenesis of jaundice in murine typhus. This rickettsiosis should be included among differential diagnoses of acute hepatitis in patients exposed to areas endemic for Rickettsia typhi.

[Cardiovascular involvement and complications in Mediterranean boutonneuse fever]. / Compromissione e complicanze cardiovascolari nella febbre bottonosa mediterranea.

After a review of the literature on heart damage in rickettsiosis, the data from a clinical and ecgraphic investigation of 17 patients suffering from boutonneuse fever are reported. There was little cardiovascular involvement and inconstant hypotension but two heart complications are described, one myocardial ischaemia which cleared up a few days after the end of the diseases, and an atrial fibrillation that lasted two days. Stress is laid on the need for constant ecgraphic monitoring, even in this minor rickettsiosis.

[Clinical features of four atypical pediatric cases of endemic typhus with pneumonia].

OBJECTIVE: To analyze clinical manifestations, treatment and prognosis of 4 cases with endemic typhus. METHOD: The clinical data of four endemic typhus patients in prognosis were retrospectively analyzed. These four atypical cases of endemic typhus with pneumonia were treated in our department from October 2011 to March 2012. They were all male, with an age range of 15 months to 7 years. The four patients had long history, mild respiratory symptom and no improvement was found after treatment with cephalosporins. There were no evidences of bacterial, viral, or fungal infections and we thought they might have infection with other pathogen. Three were from rural areas. Routine blood tests, Weil-Felix reaction, blood smear (Giemsa staining) , and indirect immunofluorescence assay were performed. RESULT: Blood smear and IFA tests showed evidences for endemic typhus. The clinical presentations were atypical, the patients had no headache, but all had fever, rash, and pneumonia of varying severity. None of the patients had a severe cough, but bronchial casts were observed in one case. Recurrent fever was reported in three cases. Physical examinations showed no eschars, but one patient had a subconjunctival hemorrhage, and one had skin scratches, cervical lymphadenopathy, pleural effusion, pericardial effusion, and cardiac dilatation. Two patients had remarkably increased peripheral blood leukocyte counts; both these patients also had high alanine aminotransferase (ALT) levels and one had a high C-reactive protein (CRP) level. Weil-Felix testing was negative or the OX19 titer was low. The peripheral blood smear (Giemsa stain) showed intracellular pathogens in all four cases. After combined therapy with doxycycline and macrolide antibiotics, all four patients recovered well. CONCLUSION: The endemic typhus children often come from rural areas. The clinical presentations were atypical, they usually have no headache, but have fever (often Periodic fever) , rash, and pneumonia of varying severity in these four cases. Combined therapy with doxycycline and macrolide antibiotics was effective in all four patients.