Clinical and laboratory features of murine typhus in central Tunisia: a report of seven cases

Rickettsia typhi central nervous system infection

A 39 year-old male was residing along the south coast of Texas, the USA, presented with fever, myalgias, headaches, and weight loss for ten days. Symptoms and manifestations progressed to include nuchal rigidity, photophobia, hyponatremia, thrombocytopenia, and transaminitis despite the intravenous administration of ceftriaxone and azithromycin. A lumbar puncture performed in the Emergency Department yielded pleocytosis and glucose cerebrospinal fluid/serum ratio of 0.35, suggestive of meningoencephalitis. Conglomerate data raised the suspicion of meningitis secondary to a zoonotic acquired infection, which was later confirmed to be Rickettsia typhi. Doxycycline is the drug of choice for the suspected Rickettsia disease. After doxycycline administration, the patient improved and was discharged home asymptomatic.

Molecular epidemiology and phylogeny of spotted fever group Rickettsia in camels (Camelus dromedarius) and their infesting ticks from Tunisia

Rickettsia species are adapted to a wide range of specific animal hosts. Camels (Camelus dromedarius) have been identified as a carrier of various zoonotic pathogens and became a focus of growing public health interest. This study reported the occurrence of rickettsial infection in camels and infesting ticks from five Tunisian governorates. Based on ompB PCR, eight out of 293 camels (2.7%) were found to be infected with Rickettsia spp. Furthermore, 13 tick specimens of Hyalomma impeltatum (10.4%) and 9 of H. dromedarii (8.0%) harboured DNA of Rickettsia bacteria with an overall prevalence rate of 9.2% (22/237). Molecular prevalence of Rickettsia infection varied significantly according to tick infestation for camels and among tick genders. Five rickettsial species, showing a potential public health interest, were revealed by sequencing. Based on ompB partial sequences, five species were identified corresponding to R. aeschlimannii, R. monacensis, R. helvetica and R. massiliae in camels and to R. africae, R. aeschlimannii, R. monacensis and R. helvetica in ticks. Based on ompA typing, three species were revealed corresponding to R. africae and R. monacensis in camels and to R. africae, R. aeschlimannii and R. monacensis in ticks. This is the first report consolidating the hypothesis that camels may serve as potential hosts for Rickettsia spp. and Hyalomma spp. ticks as possible vectors in arid and Saharan areas of Tunisia. The present data highlight the importance of preventive measures and survey that must be implemented in camel herds in order to limit the spread of these vector-borne bacteria to animals and humans.

CD4+ T Cells Are as Protective as CD8+ T Cells against Rickettsia typhi Infection by Activating Macrophage Bactericidal Activity

Rickettsia typhi is an intracellular bacterium that causes endemic typhus, a febrile disease that can be fatal due to complications including pneumonia, hepatitis and meningoencephalitis, the latter being a regular outcome in T and B cell-deficient C57BL/6 RAG1^-/- mice upon Rickettsia typhi infection. Here, we show that CD4⁺ T_H1 cells that are generated in C57BL/6 mice upon R. typhi infection are as protective as cytotoxic CD8⁺ T cells. CD4⁺- as well as CD8⁺-deficient C57BL/6 survived the infection without showing symptoms of disease at any point in time. Moreover, adoptively transferred CD8⁺ and CD4⁺ immune T cells entered the CNS of C57BL/6 RAG1^-/- mice with advanced infection and both eradicated the bacteria. However, immune CD4⁺ T cells protected only approximately 60% of the animals from death. They induced the expression of iNOS in infiltrating macrophages as well as in resident microglia in the CNS which can contribute to bacterial killing but also accelerate pathology. In vitro immune CD4⁺ T cells inhibited bacterial growth in infected macrophages which was in part mediated by the release of IFNγ. Collectively, our data demonstrate that CD4⁺ T cells are as protective as CD8⁺ T cells against R. typhi, provided that CD4⁺ T_H1 effector cells are present in time to support bactericidal activity of phagocytes via the release of IFNγ and other factors. With regard to vaccination against TG Rickettsiae, our findings suggest that the induction of CD4⁺ T_H1 effector cells is sufficient for protection.

Endemic typhus caused by Rickettsia typhi usually is a relatively mild disease. However, CNS inflammation and neurological symptoms are complications that can occur in severe cases. This outcome of disease is regularly observed in T and B cell-deficient C57BL/6 RAG1^-/- mice upon infection with R. typhi. We show here that CD4⁺ T cells are as protective as cytotoxic CD8⁺ T cells against R. typhi as long as they are present in time. This is evidenced by the fact that neither CD8⁺ nor CD4⁺ T cell-deficient C57BL/6 mice develop disease which is also true for R. typhi-infected C57BL/6 RAG1^-/- mice that receive immune CD8⁺ or CD4⁺ at an early point in time. Moreover, adoptive transfer of immune CD4⁺ T cells still protects approximately 60% of C57BL/6 RAG1^-/- mice when applied later in advanced infection when the bacteria start to rise. Although CD8⁺ T cells are faster and more efficient in bacterial elimination, R. typhi is not detectable in CD4⁺ T cell recipients anymore. We further show that immune CD4⁺ T cells activate bactericidal functions of microglia and macrophages in the CNS in vivo and inhibit bacterial growth in infected macrophages in vitro which is in part mediated by the release of IFNγ. Collectively, we demonstrate for the first time that CD4⁺ T cells alone are sufficient to protect against R. typhi infection. With regard to vaccination our findings suggest that the induction of R. typhi-specific CD4⁺ T_H1 effector T cells may be as effective as the much more difficult targeting of cytotoxic CD8⁺ T cells.

Molecular diagnosis of Rickettsia infection in patients from Tunisia

Diagnosis of rickettsioses had largely benefited from the development of molecular techniques. Unfortunately, in Tunisia, despite the large number of rickettsial cases registered every year, the Rickettsia species remain unidentified. In this study, we aimed to detect the Rickettsia species in clinical samples using molecular tests. A study was established to analyze skin biopsies, cutaneous swabs, and cerebrospinal fluid samples taken from clinically suspected patients to have rickettsial infection. Two molecular techniques were used to detect Rickettsia DNA: quantitative real time PCR (qPCR) and reverse line blot test (RLB). An analysis of the RLB hybridization assay results revealed the presence of Rickettsia DNA in skin biopsies (40.6%) and swabs (46.7%). Rickettsia conorii was the most prevalent identified species among tested samples. Other species of interest include Rickettsia typhi and Rickettsia massiliae. Using qPCR positivity rates in skin biopsies was 63.7% against 80% in swabs. R. conorii was the most frequently detected species, followed by R. typhi. The agreement between the two techniques was 68.6% (kappa=0.33). Molecular tests, especially using specific probes qPCR, allow for a rapid, better and confident diagnosis in clinical practice. They improve the survey of Mediterranean spotted fever which is considered to be the most important rickettsial infection in humans in Tunisia.

Comparison of two quantitative real time PCR assays for Rickettsia detection in patients from Tunisia

Background and objectives

Quantitative real time PCR (qPCR) offers rapid diagnosis of rickettsial infections. Thus, successful treatment could be initiated to avoid unfavorable outcome. Our aim was to compare two qPCR assays for Rickettsia detection and to evaluate their contribution in early diagnosis of rickettsial infection in Tunisian patients.

Patients and methods

Included patients were hospitalized in different hospitals in Tunisia from 2007 to 2012. Serology was performed by microimmunofluorescence assay using R. conorii and R. typhi antigens. Two duplex qPCRs, previously reported, were performed on collected skin biopsies and whole blood samples. The first duplex amplified all Rickettsia species (PanRick) and Rickettsia typhi DNA (Rtt). The second duplex detected spotted fever group Rickettsiae (RC00338) and typhus group Rickettsiae DNA (Rp278).

Results

Diagnosis of rickettsiosis was confirmed in 82 cases (57.7%). Among 44 skin biopsies obtained from patients with confirmed diagnosis, the first duplex was positive in 24 samples (54.5%), with three patients positive by Rtt qPCR. Using the second duplex, positivity was noted in 21 samples (47.7%), with two patients positive by Rp278 qPCR. Among79 whole blood samples obtained from patients with confirmed diagnosis, panRick qPCR was positive in 5 cases (6.3%) among which two were positive by Rtt qPCR. Using the second set of qPCRs, positivity was noted in four cases (5%) with one sample positive by Rp278 qPCR. Positivity rates of the two duplex qPCRs were significantly higher among patients presenting with negative first serum than those with already detectable antibodies.

Conclusions

Using qPCR offers a rapid diagnosis. The PanRick qPCR showed a higher sensitivity. Our study showed that this qPCR could offer a prompt diagnosis at the early stage of the disease. However, its implementation in routine needs cost/effectiveness evaluation.

Rickettsial diagnosis is challenging in routine laboratory. Serology offers only retrospective diagnosis. We aimed to introduce molecular methods in routine diagnosis of these infections. The lack of standardized methods led us to compare real time PCR assays previously reported in order to implement a clear strategies for diagnosis of these infections in our laboratory. Real time PCR proposed by Renvoisé et al includes two PCRs, one to detect spotted fever group and another to detect typhus group Rickettsiae. The real time PCR proposed by Giullieri et al includes a first PCR detecting 16rDNA of all Rickettsiae and if it is positive a second PCR detecting R. typhi should be performed. This second Real time PCR was shown to offer a slight higher sensitivity with a lower cost in our study. Skin biopsy specimens were more likely to show positive results than whole blood samples. Finally, positivity rates were higher among patients presenting at the first stage of the disease, essentially with negative serology.

Epidemiological, clinical and laboratory features of murine typhus in central Tunisia

OBJECTIVE

Murine typhus is an endemic zoonosis. It is difficult to diagnose because of its non-specific clinical manifestations. Our objective was to describe the epidemiological, clinical, laboratory, and treatment features of murine typhus.

METHODS

We conducted a retrospective study of 73 adult patients hospitalized for murine typhus from 2006 to 2011. The diagnosis was confirmed by a single titer of IgM≥128 or by seroconversion to typhus group antigen identified by indirect fluorescent assay.

RESULTS

The mean age of patients was 33.1 years (range, 13-68 years). Thirty-eight patients (52%) lived in rural or suburban areas; neither fleabites nor exposure to rats were reported. The most common clinical symptoms were: fever, headache, and myalgia. A maculopapular and non-confluent rash was observed in 47 patients (64.4%). No inoculation eschar was observed in any patient. Eight patients presented with interstitial pneumonia and two with lymphocytic meningitis. The diagnosis was confirmed by indirect fluorescence assay in every case. A single titer of IgM ≥ 128 was found in 62 (84.9%) cases. The other 11 cases were diagnosed by seroconversion. All patients were given antibiotics. Tetracyclines were prescribed in 57 cases (78%). The two patients presenting with meningitis were treated with fluoroquinolone. The outcome was favorable for all patients and no relapse was observed.

CONCLUSION

The features of murine typhus are non-specific. The definitive diagnosis is based on serologic testing by indirect fluorescent assay. Cyclins were the most prescribed antibiotics.

High seroprevalence for typhus group rickettsiae, southwestern Tanzania

Rickettsioses caused by typhus group rickettsiae have been reported in various African regions. We conducted a cross-sectional survey of 1,227 participants from 9 different sites in the Mbeya region, Tanzania; overall seroprevalence of typhus group rickettsiae was 9.3%. Risk factors identified in multivariable analysis included low vegetation density and highway proximity.

Murine typhus in Tunisia: a neglected cause of fever as a single symptom

OBJECTIVES

We had for aim to describe the epidemiologic and clinic characteristics of murine typhus in a series of 43 serologically confirmed cases, in our region.

PATIENTS AND METHODS

Serologic screening for IgG and IgM against Rickettsia typhi was performed in 1024 patients during three years (2006-2008). The characteristics of patients with a positive serology were examined retrospectively. One hundred and seventy sera obtained from blood donors were tested to detect IgG against R. typhi to determine the seroprevalence of the infection.

RESULTS

There was evidence of recent R. typhi infection in 43 patients (4.2%) during the study period, and 3.7% of blood donors had IgG against R. typhi. The mean age of patients was 43.1 years and the sex-ratio was 1.04. Among the patients, 58.1% were from rural areas. No patient reported any exposure to rats or rat-fleas. There were more cases during the summer and fall. The most frequent complaint was fever as a single symptom (67.5%). A cutaneous rash was reported in 44.1% and headache in 60.5% of patients. Among the patients, 44.1% presented with thrombopenia and 47.2% with elevated liver enzymes.

CONCLUSION

Murine typhus seems to be frequent in Tunisia. This infection could be a threat for travellers. Serology should be performed systematically in patients with fever as a single symptom since its clinical presentation is non-specific.

Murine typhus in southern Taiwan during 1992-2009

Clinical information regarding murine typhus in Taiwan is limited. In this study, 81 cases of serologically documented murine typhus during 1992-2009 at four referral hospitals in southern Taiwan were analyzed. There was a significant correlation between average environmental temperature and case numbers of murine typhus (r = 0.747, P = 0.005). Acute hepatitis was found in 67% of cases, and hyperbilirubinemia (serum total bilirubin ≥ 23.9 μmol/L) was found in 38%. The intervals between the initiation of appropriate therapy to defervescence were longer in patients with hyperbilirubinemia than those without hyperbilirubinemia (6.1 versus 4.1 days; P = 0.015). Nine (11.1%) showed development of severe illnesses such as acute respiratory distress syndrome (2 patients), aseptic meningitis (3), and acute renal failure (4). Only one died of acute respiratory distress syndrome. Cases of murine typhus were often found during the summer and had acute febrile hepatitis. Those patients with hyperbilirubinemia tended to have a delayed recovery even with appropriate therapy.

Murine typhus in returned travelers: a report of thirty-two cases

Murine typhus, caused by Rickettsia typhi and transmitted mainly by the rat fleas, Xenopsylla cheopis, has emerged in the field of travel medicine. We analyzed retrospectively the epidemiological, clinical, and biological characteristics of the 32 murine typhus cases that were diagnosed during the past 3 years at the World Health Organization Collaborative Center for Rickettsial diseases, Marseille, France. All of the cases occurred in travelers and most of them had returned from Africa (N = 13 of 32) and South-east Asia (N = 12 of 32). Exposure to rats was reported only in a few (N = 2 of 32) patients. Almost half of the cases were diagnosed in August and September. Only four patients presented the classic triad: fever, rash, and headache. Moreover, we report the first known cases of a hemophagocytic syndrome associated with this disease. Murine typhus must be considered as an etiologic agent of febrile illness in returning travelers, particularly in those with unspecific symptoms.

Murine typhus in central Greece: epidemiological, clinical, laboratory, and therapeutic-response features of 90 cases

OBJECTIVES

To document and evaluate the clinico-epidemiological profile of murine typhus during the re-emergence of the disease in a previously endemic focus in central Greece.

METHODS

This was a 5-year, hospital-based, observational study, in which 90 adult patients with murine typhus were prospectively identified and studied.

RESULTS

Most cases of the disease occurred in rural (52%) and semi-urban (34%) settings, with a seasonal frequency peak during the late summer. The triad of fever, headache, and rash was present in 64% of the patients within 2 days of hospital admission. Normal white blood cell counts (63%), thrombocytopenia (81%), and a high erythrocyte sedimentation rate (93%) were the main hematological findings upon presentation. Elevated aminotransferases (>84%), hypoalbuminemia (81%), and hyponatremia (36%) were prominent biochemical abnormalities. Pulmonary, neurological, and renal complications were noted in 26% of the patients and subsided after specific treatment. The duration of fever was shorter in patients treated with doxycycline (median 3 days) compared to ofloxacin (p=0.001) or doxycycline plus ofloxacin (p=0.009).

CONCLUSIONS

Murine typhus has the potential to cause significant morbidity. Awareness of the disease in endemic areas, early recognition of its clinical and laboratory features, and prompt administration of effective treatment are key factors to prevent potentially severe complications.

Murine typhus in Cyprus: a 9-year survey

Epidemiological and clinical data of 193 human cases of murine typhus in Cyprus were recorded and analysed during a 9-year period (2000-2008). The incidence rate was estimated at 24.5 cases/100,000 population/year. The incidence rate varied considerably between rural, urban and semi-urban areas, with residents in rural areas accounting for 79.3% of the total cases. Most (72.5%) of the cases occurred in late summer (July and August) and early autumn (September to October) with a peak in September. Well-established persistent endemic foci with clusters of cases were identified and characterised as 'high risk' areas. Presence of or contact with rats and fleas, presence of domestic/peridomestic animals and residence in rural areas, especially locations near the 'green line' (a narrow zone patrolled by UN forces that separates the northern and southern parts of the island), increased the possibility of murine typhus infection. The results of the current study enhance the belief that murine typhus is a serious public health problem in Cyprus.

Murine typhus in the homeless

Homeless populations are particularly exposed to many vector-borne diseases because of their poor living conditions. We tested sera from 299 homeless people recruited in 2010 and 2011 in Marseilles, France for antibodies to Rickettsia typhi by microimmunofluorescence using a titer of 1:25 as a cut-off titer, and we confirmed the results by Western blot and cross-adsorption studies. Sixty-three persons (22%) had antibodies against R. typhi. The murine typhus seroprevalence rates have significantly increased in homeless populations between the 2000-2003 and 2010-2011 periods. These findings indicate that the homeless are increasingly exposed to flea-borne murine typhus in Marseilles. One might suggest that multiple strikes of sanitation workers resulting in the increase of waste and construction sites combined with the poor living conditions of the homeless expose this population to rodents and their fleas. Further annual studies are necessary to follow rodent-associated diseases among homeless people in Marseille.

Murine typhus as a cause of Fever in travelers from Tunisia and mediterranean areas

BACKGROUND

Travelers are exposed to a variety of health risks in unfamiliar environments and fever is a common problem in patients returning from travel abroad. Rickettsial diseases are increasingly frequently being reported among international travelers. Here we present cases of Rickettsia typhi infection, the agent of murine typhus, that were identified in our laboratory the last year, in travelers from Tunisia.

METHODS

For each patient we tested an acute-phase serum sample and for one patient we tested a convalescent-phase serum sample. IgG and IgM antibody titers were estimated with use of the microimmunofluorescence (MIF) assay. Western blot (WB) assay was performed for all the patients.

RESULTS

We identified three cases of murine typhus after a travel in Tunisia. All cases were observed during late summer and early autumn and patients were suffering by persistent fever. None of them presented rash or inoculation eschar. MIF was positive for Rickettsia sp. in the acute-phase serum samples of two patients. In one patient, two acute-phase serum samples were Rickettsia sp. negative whereas a third convalescent-phase serum sample that was obtained 2 weeks after was Rickettsia sp. positive. By WB assay we identified infection by R typhi. A treatment was immediately started and patients became apyretic.

CONCLUSIONS

In the countries of North Europe, although autochthones cases of murine typhus have not been described, sporadic cases of R typhi infection are identified in travelers who visited murine typhus endemic areas. Murine typhus should be considered in the diagnosis of febrile illness without rash in travelers returning from disease endemic areas, like the south Mediterranean area.

Epidemiological study of rickettsial infections in patients with hypertransaminemia in Madrid (Spain)

A retrospective analysis was performed to detect anti-rickettsial antibodies in the serum of patients with hypertransaminemia of unknown etiology, and in that of healthy members of the general population of Madrid (Spain). Among 143 patients 16 (11.2%) were positive for anti-R. conorii IgG antibodies and 7% for R. typhi. PCR analysis was performed in patients with IgM antibodies. Among 143 healthy subjects from the general population, seven (4.9%) were positive for anti-R. conorii IgG antibodies, and 2.8% for R. typhi. These results show that anti-rickettsial antibodies are more commonly detected in patients with hypertransaminemia than in healthy people.

Méningite révélant une infection à Rickettsia typhi

INTRODUCTION

Neurological manifestations are rarely observed in murine typhus. We present a case of meningitis caused by Rickettsia typhi.

EXEGESIS

We report a case of Tunisian 57-year-old woman admitted for suspicion of meningitis. Clinical examination revealed fever at 39,5 degrees C and nuchal rigidity. There were no focal neurologic signs, cutaneous rash or eschar. Lumbar puncture showed clear cerebrospinal fluid containing normal glucose, 0,48 g/l protein and 30 WBC (78% lymphocyte). Gram-stained smear and culture were negative. Serology confirmed the diagnosis. The patient was initially treated by ampicillin 12 g daily but remained febrile. Retinal lesions were detected on ophthalmic examination, suggesting rickettsial infection. Clinical outcome was good after 7-day treatment with oral ciprofloxacin 1,5 g daily. The mean follow-up was six months.

CONCLUSION

Murine typhus is an endemic zoonosis. Neurological manifestations were uncommon. An ophthalmic examination is recommended if rickettsiosis was suspected.

Epidemiology of rickettsioses in North Africa

The first description of Mediterranean spotted fever (MSF) was made by Conor and Brush in 1910 in Tunisia, where, at the same time, Nicolle described the role of lice in transmission of epidemic typhus. However, along this century, there have been few and fragmentary reports about ecology and epidemiology of rickettsioses in North Africa. This region was always considered, for these diseases, like other Mediterranean regions. The most human tick-borne rickettsiosis known to occur in North Africa is MSF caused by R. conorii and transmitted by the brown dog tick, Rhipicephalus sanguineus. Recent studies showed that other arthropode-transmitted rickettsiae are prevalent in North Africa: R. aeschlimannii, R. massiliae, and R. felis. Moreover, R. felis and R. aeschlimannii human infection were respectively confirmed, by serology in Tunisia, and by PCR in Morocco. The seroprevalence of R. conorii among healthy population was ranging from 5% to 8% in most of the countries. Epidemiological and clinical features are frequently resumed in an eruptive fever with eschar occurring in hot season in rural areas. Typhus group rickettsioses, caused by R. typhi and R. prowazekii are less frequently reported than in the 1970s. Seroprevalence of R. typhi among blood donors was from 0.5% to 4%. In Algeria about 2% of febrile patients had R. prowazekii antibodies. Moreover, reemerging threat of epidemic typhus should be considered, after the two cases recently diagnosed in the highlands of Algeria. Murine typhus, considered as "benign" typhus, is underestimated. When R. typhi was inserted in serologic tests, murine typhus became more frequently confirmed. In a recent study in Central Tunisia, we confirmed an emergence of murine typhus mistaken for R. conorii or viral infection. In addition to typhus surveillance, future studies have to determine which spotted fever group rickettsiae are prevalent in vectors and in human pathology.

Serologic study of rickettsioses among acute febrile patients in central Tunisia

Although Mediterranean spotted or "boutonneuse" fever (MSF) has been documented in central Tunisia, other spotted fever group rickettsioses (SFGR) and typhus group rickettsioses (TGR) have received little attention in our region. We sought to determine the role of rickettsioses, Q fever, ehrlichioses, and bartonelloses among patients with acute fever. The results of this study of 47 persons with acute fever of undetermined origin are reported in this paper. We concluded that SFGR, murine typhus, and acute Q fever are common causes of acute isolate fever in summer in central Tunisia and should be investigated systematically in patients with acute fever of unknown origin.

Tropical rickettsioses

In recent years, a bewildering array of emerging rickettsial pathogens have been described throughout the world, including in the tropics. Here we present an updated overview of scrub typhus, murine typhus, and epidemic typhus. We also present an update on the emerging spotted fever group rickettsioses described in the tropics through 2005, focusing on epidemiologic and clinical data and management.

13 – Antibiotic therapy of community-acquired pneumonia (CAP) caused by atypical agents

Macrolides, fluoroquinolones, doxycycline, and ketolides show a good intrinsic activity against intracellular pathogens which are responsible for a variable percentage of community-acquired pneumonia (CAP). These therapeutic agents all seem effective in treating most cases of CAP caused by Mycoplasma pneumoniae, Chlamydia pneumoniae, or Legionella spp. Among quinolones, the more recent fluoroquinolones, such as gemifloxacin or moxifloxacin, generally show a better intrinsic activity than the older ones. Among macrolides, azithromycin, and clarithromycin show a better pharmacokinetic profile. Both of them are available in intravenous form. It is quite common for M. pneumoniae and C. pneumoniae to continue to be shed in respiratory secretions, weeks after an effective therapy. The clinical relevance of this finding is not clear since most of these patients have a good outcome. Azithromycin, due to its advantageous pharmacokinetic profile, seems the best option when antibiotic prophylaxis is considered in some epidemiological settings. It has been proved effective in closed M. pneumoniae outbreaks.