Retinochoroiditis secondary to Rickettsia typhi infection: a case report

BACKGROUND

To report a case of unusual presentation of retinochoroiditis caused by Rickettsia typhi in a patient without prior uveitis.

CASE PRESENTATION

In this case, we describe a 24-year-old male soldier with no previous eye disease, who was referred to our ophthalmology department due to bilateral retinochoroiditis and vitritis. The patient initially presented with a paracentral scotoma in his right eye persisting for 7 days and scattered dark spots in his left eye for 2 days in June 2023. Preceding these ocular symptoms, he experienced a two-week episode of fever, headaches, night sweats, and rapid weight loss of 10 kg. A transient rash covered his body briefly. His mother had a history of recurrent eye inflammation. Physical examination revealed bilateral keratic precipitates on the lower corneal periphery, 1 + anterior vitreous cells, small retinal lesions and mild optic discs elevation. Fluorescein angiography indicated mild discs hyperfluorescence, and the clinically visible round punctate lesions on OCT showed inner retinal hyper-reflective lesion with a depth till outer plexiform layer possibly suggestive of a retinitis lesion. Laboratory tests were normal except thrombocytosis, elevated ESR, liver enzymes and ACE levels, with positive Rickettsia typhi serology tests. Rheumatology and infectious disease consultations ruled out autoimmune diseases, confirming Rickettsia typhi infection. Treatment included systemic doxycycline and prednisone, with improvement of visual acuity, ocular symptoms, OCT abnormalities and resolution of inflammation. Prednisone was discontinued, and after two months, additional improvement was seen clinically, with preserved retinal structures on OCT.

CONCLUSION

This study explores retinochoroiditis as a rare ocular presentation of Rickettsia typhi, an unusual infection in the Middle East. Previously reported ocular manifestations include conjunctivitis, vitritis, post infectious optic neuropathy and a few cases of uveitis. Ocular symptoms followed systemic illness, highlighting the need for awareness among clinicians. Diagnosis relies on seroconversion, with fluorescein angiography and OCT aiding in assessment. Empiric doxycycline and systemic corticosteroid therapy is recommended. Ocular symptoms resolved in two months. Awareness of these ocular manifestations is essential for timely diagnosis and management. Further research is needed to fully understand this aspect of murine typhus.

Severe murine typhus complicated by multiple organ dysfunctions: A case report

Background

Rickettsioses are infectious diseases which are caused by intracellular bacteria which belong to the family Rickettsiaceae. This zoonosis endemically prefers tropical and subtropical regions of which the Mediterranean is included. Murine typhus is a type of rickettsial disease that commonly presents with undulating fever, headache rash, chills, malaise, and myalgias. It can lead to complications such as multi-organ failure and has a lethality rate of <5% in such cases.

Case Presentation

A 70-year-old male was hospitalized at the Unit of Infectious Diseases, Mother Teresa Hospital, Tirana, Albania in a comatose condition. He had a seven-day history of fever up to 39-40°C, headache, fatigue, anorexia, vomiting, cough, and myalgia. He was a farmer and had contact with animals. Upon admission, he had scleral hemorrhages, hepatosplenomegaly, jaundice, maculopapular rash over the trunk, abdomen, and palms of his hands as well as severe acidosis, depressed bicarbonate levels, alteration in liver, kidney, and pancreas function tests. He was urgently transferred to the Intensive care unit of the Infectious Diseases Department. He was hemodynamically unstable and was put immediately on vasoactive agents and mechanical ventilation. ELISA Rickettsia typhi IgM resulted positive. Supportive treatment along with antibiotics Levofloxacin and Ceftriaxone was initiated. However, the patient died on the 4th day of hospitalization and the 11th of the disease onset.

Conclusion

Murine typhus should be included in the investigation of possible causes when dealing with patients presenting with fever and maculopapular rash complicated by multi-organ failure and coming from a typhus-endemic area, especially in the summer season.

Detection of Severe Murine Typhus by Nanopore Targeted Sequencing, China

We report a case of murine typhus in China caused by Rickettsia typhi and diagnosed by nanopore targeted sequencing of a bronchoalveolar lavage fluid sample. This case highlights that nanopore targeted sequencing can effectively detect clinically unexplained infections and be especially useful for detecting infections in patients without typical signs and symptoms.

Rickettsioses in Colombia during the 20th century: A historical review

Rickettsioses are vector-borne zoonotic diseases whose etiological agents are bacteria of the genera Rickettsia and Orientia. In Colombia, literature published on rickettsioses during the 20th century is limited and disperse; to date, there are no detailed publications that compile the affected regions or the involved Rickettsia species in each outbreak. Since early works of Luis Patiño-Camargo, the study of rickettsioses gained major importance with the subsequent description of significant outbreaks in some departments of the country. During the 1940s, many articles were published reporting outbreaks probably caused by Rickettsia rickettsii, Rickettsia typhi, and Rickettsia prowazekii, as well as studies on their diagnosis, vaccination, and prophylaxis. One of the most notorious works was published by Patiño-Camargo where he named the R. rickettsii rickettsiosis as "Tobia fever". However, in the subsequent decades, these entities entered a prolonged period of neglected research and surveillance, and just gained importance until the 21st century, when new fatal cases began to be reported in the country; thus, many questions remained unanswered during this overlooked period. The present work reviewed online databases, repositories, and libraries to compile literature related to rickettsioses in Colombia published during the 20th century. Gathered data show that typhus group rickettsioses (including infections by R. typhi and R. prowazekii) were broadly distributed in departments from the Andean and Caribbean regions, and that spotted fever group rickettsioses cases (including infections by R. rickettsii) were registered in other locations different from Tobia (Cundinamarca), like Atlántico, Bolivar, and Santander departments. These findings contribute to the knowledge of these diseases, their historical distribution, public health burden, and set new horizons for rickettsioses research in different Colombian locations.

Rickettsia typhi infection in a clinically-ill dog from Houston, Texas

In 2020, Rickettsia typhi was diagnosed in a dog from Houston, Texas, USA based upon R. typhi IFA seroreactivity in both acute and convalescent sera, and PCR with DNA sequencing of 4 different gene regions, all of which were 100% identical to R. typhi. The dog was clinically ill with intermittent fever, lethargy, inappetence, and lymphadenopathy. Clinicopathological abnormalities included a mild nonregenerative anemia, neutrophilia, lymphopenia, thrombocytopenia, hypoalbuminemia, and elevated ALP. The dog rapidly recovered with doxycycline administration.

Murine typhus complicated by sHLH mimicking adult-onset Still's disease

INTRODUCTION

Adult-onset Still's disease (AOSD) is a rare multisystemic disorder and a diagnostic challenge for physicians because of the wide range of differential diagnoses. Common features of AOSD and secondary hemophagocytic lymphohistiocytosis (sHLH) could favour diagnostic uncertainty, in particular in case of infection-related sHLH.

OBSERVATION

A 61-year-old man was admitted to our internal medicine department for suspected AOSD. He reported a 2-week history of sudden onset fever, headaches, myalgia, sore throat, diarrhoea, and an erythematous macular rash of the trunk as well as petechial purpuric lesions on both legs on return from Reunion Island. Laboratory tests found cytopenia, hepatic cytolysis, hypertriglyceridaemia, and hyperferritinaemia. Hemophagocytosis was diagnosed on bone marrow aspiration in favour of the diagnosis of secondary hemophagocytic lymphohistiocytosis (sHLH). Subcutaneous anakinra (100mg) was initiated to treat sHLH with favourable course. Oral doxycycline was added 3days later because of atypical features for AOSD diagnosis such as diarrhoea, hypergammaglobulinaemia, and doubtful serologies for Rickettsia and Coxiella. Three weeks later, Rickettsia typhi serology was checked again and revealed an increase in IgG titer>4 times that confirmed the diagnosis of murine typhus. A diagnosis of murine typhus complicated by sHLH was retained, successfully treated by anakinra and doxycycline.

CONCLUSION

Our observation shows that AOSD diagnosis has to be stringent due to the many differential diagnoses, particularly infection complicated by sHLH, which may be rare. It is important to consider murine typhus in patients returning from endemic areas, such as La Reunion or other tropical areas, when they present fever of unknown origin with non-specific clinical features. Moreover, this case illustrates the effectiveness of IL-1 blockers as a treatment for symptomatic sHLH without severity criteria, regardless of the aetiology.

Abducens nerve palsy with associated retinal involvement secondary to rickettsia typhi infection

OBJECTIVE

To report a case of abducens nerve palsy with associated retinal involvement due to rickettsia typhi infection.

MATERIAL AND METHODS

A single case report documented with multimodal imaging.

RESULTS

A 18-year-old woman with a history of high-grade fever was initially diagnosed with typhoid fever and treated with fluoroquinolone. She presented with a 5-day history of diplopia and headaches. Her best-corrected visual acuity was 20/20 in both eyes. Ocular motility examination showed left lateral gaze restriction. Lancaster test confirmed the presence of left abducens palsy. Fundus examination showed optic disc swelling in both eyes associated with superotemporal retinal hemorrhage and a small retinal infiltrate with retinal hemorrhage in the nasal periphery in the left eye. Magnetic resonance imaging (MRI) of the brain and orbits showed no abnormalities. A diagnosis of rickettsial disease was suspected and the serologic test for Richettsia Typhi was positive. The patient was treated with doxycycline (100 mg every 12 h) for 15 days with complete recovery of the left lateral rectus motility and resolution of optic disc swelling, retinal hemorrhages, and retinal infiltrate.

CONCLUSION

Rickettsial disease should be considered in the differential diagnosis of abducens nerve palsy in any patient with unexplained fever from endemic area. Fundus examination may help establish an early diagnosis and to start an appropriate rickettsial treatment.

Serological evidence indicates widespread distribution of rickettsioses in Myanmar

•

Diagnosis of rickettsial infections is difficult in low-resource settings; this leads to delays in receiving appropriate treatment.

•

Before this study, the distribution of rickettsioses in Myanmar was not known.

•

This serosurvey shows that rickettsioses are widespread in Myanmar.

•

Particularly high prevalence of scrub typhus was found in central and northern regions.

Background

Little research has been published on the prevalence of rickettsial infections in Myanmar. This study determined the seroprevalence of immunoglobulin G (IgG) antibodies to rickettsial species in different regions of Myanmar.

Methods

Seven hundred leftover blood samples from patients of all ages in primary care clinics and hospitals in seven regions of Myanmar were collected. Samples were screened for scrub typhus group (STG), typhus group (TG) and spotted fever group (SFG) IgG antibodies using enzyme-linked immunosorbent assays (ELISA). Immunofluorescence assays were performed for the same rickettsial groups to confirm seropositivity if ELISA optical density ≥0.5.

Results

Overall IgG seroprevalence was 19% [95% confidence interval (CI) 16–22%] for STG, 5% (95% CI 3–7%) for TG and 3% (95% CI: 2–5%) for SFG. The seroprevalence of STG was particularly high in northern and central Myanmar (59% and 19–33%, respectively). Increasing age was associated with higher odds of STG and TG seropositivity [per 10-year increase, adjusted odds ratio estimate 1.68 (p < 0.01) and 1.24 (p = 0.03), respectively].

Conclusion

Rickettsial infections are widespread in Myanmar, with particularly high seroprevalence of STG IgG antibodies in central and northern regions. Healthcare workers should consider rickettsial infections as common causes of fever in Myanmar.

Two cases of uveitis associated with severe transaminitis during a Rickettsia typhi outbreak in Los Angeles County

Purpose

To report the clinical presentation, multimodal imaging, and management of two patients with Rickettsia typhi infection who presented with transaminitis and bilateral uveitis.

Observations

We report two cases of murine typhus-associated uveitis in the setting of a Rickettsia typhi outbreak in Los Angeles County. In case 1, a 29-year-old Hispanic female presented with scotoma of the right eye and bilateral floaters after 2 weeks of persistent fevers, maculopapular rash, and arthralgia. Clinical examination and optical coherence tomography (OCT) revealed vitreous cell and scattered white spots in both eyes at the level of the inner retina, and a cotton wool spot inferiorly in the left eye. Multiple hyperautofluorescent spots were seen on widefield fundus autofluorescence (FAF). Retinal vascular leakage and optic disc hyperfluorescence were visualized on widefield fluorescein angiography (FA). These findings were concerning for a white dot syndrome (WDS). The patient was started on oral prednisone 30 mg daily. Serologic testing during the convalescent phase returned positive for R. typhi infection and she was started on doxycycline. 3 weeks later, she reported complete resolution of scotoma and significant improvement of bilateral floaters.

In the second case, a 42-year-old Hispanic male presented with sudden bilateral increased floaters and blurry vision after 12 days of persistent fever and headache. Clinical examination revealed trace flare with 1+ cell in the anterior chamber, 1+ vitreous cell, and multiple white dots in both eyes at the level of the inner retina. FAF showed scattered hyperautofluorescent spots in both eyes. FA demonstrated late retinal vascular leakage with bilateral hyperfluorescent optic discs. He was started on oral prednisone 40mg, prednisolone acetate 1% drops, and cyclopentolate 1% drops daily. 2 weeks later, serologic titers returned positive for murine typhus and he was started on doxycycline with gradual taper off of steroids. He subsequently had complete resolution of floaters, blurry vision, and the inner retinal white spots.

Conclusions and Importance

Murine typhus-associated uveitis may present with scotoma and increased floaters in the setting of persistent fevers and transaminitis, with pre- or inner retinal white spots seen on fundus examination. Ophthalmologists may aid in prompt diagnosis and initiation of antibiotic therapy, which can shorten the course of the disease and in turn, reduce the risk of severe complications.

Serum C-reactive protein and procalcitonin values in acute Q fever, scrub typhus, and murine typhus

Background

Although C-reactive protein (CRP) and procalcitonin (PCT) are widely used inflammatory markers for infectious diseases, their role and potential application for rickettsioses were rarely studied.

Methods

A retrospective chart review and serological study were conducted in patients with rickettsioses. The clinical presentations, characteristics, laboratory data, and treatment responses were recorded and their associations with CRP and PCT values were analyzed.

Results

A total of 189 cases of rickettsioses, including 115 cases of acute Q fever (60.8%), 55 cases of scrub typhus (29.1%), and 19 cases of murine typhus (10.1%) were investigated. Both CRP and PCT values increased in the acute phase and declined in the convalescent phase. In the acute phase, mean CRP and PCT values were 78.2 ± 63.7 mg/L and 1.05 ± 1.40 ng/mL, respectively. Percentages of patients falling under different cut-off values of CRP and PCT were calculated systematically. Only 10.8% of CRP was > 150 mg/L and 14.2% of PCT was > 2.0 ng/mL. Patients with delayed responses to doxycycline treatment (> 3 days from treatment to defervescence) had significantly higher CRP values (102.7 ± 77.1 vs. 72.2 ± 58.2 mg/L, p = 0.041) and more PCT > 1.0 ng/ml (48.4% vs. 26.0%, p = 0.019) in the acute phase; higher CRP values (19.1 ± 37.4 vs. 3.6 ± 13.1 mg/L, p = 0.049) and more PCT > 0.5 ng/ml (19.2% vs. 1.4%, p = 0.005) in the convalescent phase. Correlation analysis was conducted for patients with acute Q fever. CRP and PCT values were positively correlated to each other, and both markers also had a positive correlation with serum aspartate transaminase values. Both CRP and PCT values and white blood cell counts were positively correlated to the days needed from doxycycline treatment to defervescence.

Conclusion

CRP and PCT values might be useful in clinical investigations for patients with suspected rickettsioses and in predicting the response to doxycycline treatment for rickettsioses.

Rickettsia typhi infection presenting as severe ARDS

Murine typhus, also known as endemic typhus, is a disease resulting from an infection caused by the gram-negative bacillus Rickettsia typhi. Murine typhus is identified worldwide, predominantly in tropical and subtropical geographic locations. Transmission occurs through direct inoculation by an arthropod vector, most commonly the rat flea, Xenopsylla cheopis. rickettsial infections are notorious for disseminated infections throughout the endothelial cells. The increase in permeability is an immediate consequence and has the potential of leading to non-cardiogenic pulmonary edema, otherwise known as acute respiratory distress syndrome (ARDS). Clinical manifestations are non-specific and initially mimic typical viral etiologies, obscuring early diagnosis. As a result, clinicians often do not include rickettsial infections in their differential diagnoses. Definitive diagnosis is based on clinical recognition, epidemiologic awareness, and serological testing. Here we present a confirmed case of murine typhus in a young non-immunocompromised patient who developed ARDS one week from the initial onset of symptoms.

The Rickettsioses: A Practical Update

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.

The temporal dynamics of humoral immunity to Rickettsia typhi infection in murine typhus patients

OBJECTIVES

This study examined individuals with Rickettsia typhi infection in the Lao People's Democratic Republic (Lao PDR) to (a) investigate humoral immune dynamics; (b) determine the differences in reference diagnostic results and recommend appropriate cut-offs; (c) determine differences in immune response after different antibiotic treatments; and (d) determine appropriate diagnostic cut-off parameters for indirect immunofluorescence assay (IFA).

METHODS

Sequential serum samples from 90 non-pregnant, adults were collected at seven time-points (days 0, 7, 14, 28, 90, 180 and 365) as part of a clinical antibiotic treatment trial. Samples were tested using IFA to determine IgM and IgG antibody reciprocal end-point titres against R. typhi and PCR.

RESULTS

For all 90 individuals, reciprocal R. typhi IgM and IgG antibody titres ranged from <400 to ≥3200. The median half-life of R. typhi IgM was 126 days (interquartile range 36-204 days) and IgG was 177 days (interquartile range 134-355 days). Overall median patient titres for R. typhi IgM and IgG were significantly different (p < 0.0001) and at each temporal sample collection point (range p < 0.0001 to p 0.0411). Using Bayesian latent class model analysis, the optimal diagnostic cut-off reciprocal IFA titer on patient admission for IgM was 800 (78.6%, 95% CI 71.6%-85.2% sensitivity; 89.9%, 95% CI 62.5%-100% specificity), and for IFA IgG 1600 (77.3%; 95% CI 68.2%-87.6% sensitivity; 99%, 95% CI 95%-100% specificity).

CONCLUSIONS

This study suggests suitable diagnostic cut-offs for local diagnostic laboratories and other endemic settings and highlights antibody persistence following acute infection. Further studies are required to validate and define cut-offs in other geographically diverse locations.

Emergence of murine typhus in La Réunion, France, 2012-2017

OBJECTIVE

Murine typhus (MT) is an acute zoonosis caused by Rickettsia typhi, a flea-borne rickettsiosis. The first autochthonous case was reported in 2012. Once autochthonous transmission of Rickettsia typhi was proven, we performed a prospective study to describe and raise awareness of this often-misdiagnosed disease among physicians.

PATIENTS AND METHODS

We performed a prospective observational study of MT cases in La Réunion from 2012 to 2017. MT cases were defined as clinically compatible illnesses with a specific positive serology and/or PCR.

RESULTS

Sixty-one confirmed cases were collected. The main clinical features were prolonged fever (90%), asthenia (87%), and headaches (79%). The main biological abnormalities were elevated liver enzymes (84%) and thrombopenia (75%). Renal function was normal in 90% of cases; it was an important feature because leptospirosis is a frequent cause of acute renal failure. A seasonal factor was observed with 79% of cases reported in the warm season and most of them in the west and south of the island (i.e., the dry areas).

CONCLUSION

MT is an emerging disease in La Réunion, and local conditions could lead to an endemic situation. Cases of acute undifferentiated fever with headaches should guide to the diagnosis of MT especially in the warm season and dry areas. Leptospirosis is an alternative diagnosis, which differs from MT by its epidemiological characteristics and by the associated frequent renal dysfunction.

Seroprevalence of typhus group and spotted fever group Rickettsia exposures on Reunion island

Objective

Murine typhus has been increasingly reported on Reunion island, Indian ocean, following documentation of eight autochthonous infections in 2012–2013. We conducted a serosurvey to assess the magnitude of the seroprevalence of rickettsioses in the population. Two hundred and forty-one stored frozen sera taken from the 2009 Copanflu-RUN cohort were analysed using an immunofluorescence assay allowing to distinguish typhus group (TGR) and spotted fever group Rickesttsiae (SFGR). Seropositivity was defined for a dilution titre of Rickettsia IgG antibodies ≥ 1:64. Seroprevalence was weighted to account for the discrepancy between the Copanflu-RUN subset and the general population, as to infer prevalence at community level. Prevalence proportion ratios (PPR) were measured using log-binomial models.

Results

The weighted seroprevalences of typhus group rickettsioses and spotted fever group rickettsioses were of 12.71% (95% CI 8.84–16.58%) and 17.68% (95% CI 13.25–22.11%), respectively. Pooled together, data suggested that a fifth of the population had been exposed at least to one Rickettsia group. Youths (< 20 years) were less likely seropositive than adults (adjusted PPR 0.13, 95% CI 0.01–0.91). People living in the western dryer part of the island were more exposed (adjusted PPR 2.53, 95% CI 1.07–5.97). Rickettsioses are endemic on Reunion island and circulated before their first identification as murine typhus in year 2011. Surprisingly, since isolation of Rickettsia africae from Amblyomma variegatum in year 2004 or isolation of Rickettsia felis from Amblyomma loculosum, no autochthonous cases of African tick-bite fever or flea-borne spotted fever has yet been diagnosed.

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4416-8) contains supplementary material, which is available to authorized users.

Murine typhus presenting with status epilepticus

Patients with rickettsial infection usually present with a febrile illness, headache, arthromyalgia and various biochemical abnormalities. Neurologic involvement is rare in murine typhus. Here, we report a case of a patient who presented with status epilepticus secondary to Rickettsia typhi infection.

Tick- and flea-borne rickettsioses in Tizi-Ouzou, Algeria: Implications for travel medicine

BACKGROUND

In Algeria, Mediterranean spotted fever (MSF), caused by Rickettsia conorii conorii and transmitted by Rhipicephalus sanguineus, is endemic. However, the documentation of cases is rare due to a lack of laboratory facilities. Our aim was to screen for rickettsioses in patients with fever, rash and a possible inoculation eschar.

MATERIALS AND METHODS

Between 2013 and 2015, patients with a fever and a rash presenting at hospitals in the Tizi-Ouzou region were prospectively included in our study. Sera were screened using Indirect Immunofluorescence Assay (IFA) and qPCR was performed on swab samples from eschars.

RESULTS

One hundred and sixty-six patients were included. For 57 patients, MSF due to R. conorii conorii was diagnosed by serology and qPCR on a swab eschar sample. Three patients were diagnosed with murine typhus, a flea borne rickettsiosis. In addition, two patients had a positive serology in IgM for R. felis. For nine patients, serology for rickettsiosis was positive, but the specific rickettsia involved could not be determined. Nine patients had a severe disease with neurological involvement or multi-organ failure.

CONCLUSION

Clinicians should routinely screen for rickettsioses in patients and travellers presenting with a rash upon return from Algeria. Doxycycline treatment must be given promptly because the prognosis can be severe.

Seroprevalence of spotted fever group and typhus group rickettsiae in individuals with acute febrile illness from Gorakhpur, India

BACKGROUND

The aim of this study was to estimate the seroprevalence of spotted fever group (SFG) and typhus group (TG) rickettsiae among individuals with acute febrile illness (AFI) in the scrub typhus endemic district of Gorakhpur in India. This district is one of the worst affected by annual seasonal acute encephalitis syndrome (AES) outbreaks.

METHODS

Antibodies against SFG and TG rickettsiae and the associated risk factors were determined in 294 individuals presenting with an AFI, encountered during a community-based survey conducted during the AES outbreak period October-November 2016.

RESULTS

Respective IgM and IgG seropositivity was 13.6% and 36.7% for SFG, and 7.1% and 15.3% for TG. SFG IgM positivity was significantly higher among females, while IgG positivity was significantly higher among individuals ≥45 years of age. IgM and IgG seropositivity for TG rickettsiae were significantly higher in individuals involved in outdoor activities and housewives, but did not differ according to age group, sex, or educational status.

CONCLUSION

The study results present serological evidence of SFG and TG rickettsiosis, in addition to scrub typhus, among individuals with AFI in Gorakhpur region and indicate the need to explore their roles as potential causes of AES in the region.

Characteristics of scrub typhus, murine typhus, and Q fever among elderly patients: Prolonged prothrombin time as a predictor for severity

BACKGROUND/PURPOSE

The clinical manifestations of scrub typhus, murine typhus and acute Q fever in the elderly are not clear.

METHODS

We conducted a retrospective study to identify the characteristics of the elderly aged ≥65 years with a comparison group aged 18-64 years among patients with scrub typhus, murine typhus, or acute Q fever who were serologically confirmed at three hospitals in Taiwan during 2002-2011.

RESULTS

Among 441 cases, including 187 cases of scrub typhus, 166 acute Q fever, and 88 murine typhus, 68 (15.4%) cases were elderly patients. The elderly had a higher severe complication rate (10.3% vs. 3.5%, p = 0.022), but did not have a significantly higher mortality rate (1.47% vs. 0.54%, p = 0.396). Compared with those without severe complications, we found the elderly (p = 0.022), dyspnea (p = 0.006), less relative bradycardia (p = 0.004), less febrile illness (p = 0.004), prolonged prothrombin time (PT) (p = 0.002), higher levels of initial C-reactive protein (p = 0.039), blood leukocyte counts (p = 0.01), and lower platelet counts (p = 0.012) are significantly associated with severe complications. Only prolonged prothrombin time was associated with severe complications in multivariate analysis (p = 0.018, CI 95% 0.01-0.66). Among clinical symptoms and laboratory data, multivariate analysis revealed chills was less frequently occurred in the elderly (p = 0.012, 95% confidence interval [CI]: 1.33-9.99).

CONCLUSION

The elderly cases with scrub typhus, murine typhus, or acute Q fever would be more likely to have severe complications, for which prothrombin time prolongation is an important predictor for severe complications.

Direct evidence of Rickettsia typhi infection in Rhipicephalus sanguineus ticks and their canine hosts

Murine typhus is a rickettsiosis caused by Rickettsia typhi, whose transmission is carried out by rat fleas in urban settlements as classically known, but it also has been related to cat fleas in a sub-urban alternative cycle that has been suggested by recent reports. These studies remarks that in addition to rats, other animals like cats, opossums and dogs could be implied in the transmission of Rickettsia typhi as infected fleas obtained from serologically positive animals have been detected in samples from endemic areas. In Mexico, the higher number of murine typhus cases have been detected in the Yucatan peninsula, which includes a great southeastern region of Mexico that shows ecologic characteristics similar to the sub-urban alternative cycle recently described in Texas and California at the United States. To find out which are the particular ecologic characteristics of murine typhus transmission in this region, we analyzed blood and Rhipicephalus sanguineus ticks obtained from domestic dogs by molecular approaches, demonstrating that both samples were infected by Rickettsia typhi. Following this, we obtained isolates that were analyzed by genetic sequencing to corroborate this infection in 100% of the analyzed samples. This evidence suggests for the first time that ticks and dogs could be actively participating in the transmission of murine typhus, in a role that requires further studies for its precise description.

Molecular and serological evidence of flea-associated typhus group and spotted fever group rickettsial infections in Madagascar

Background

Rickettsiae are obligate intracellular bacteria responsible for many febrile syndromes around the world, including in sub-Saharan Africa. Vectors of these pathogens include ticks, lice, mites and fleas. In order to assess exposure to flea-associated Rickettsia species in Madagascar, human and small mammal samples from an urban and a rural area, and their associated fleas were tested.

Results

Anti-typhus group (TGR)- and anti-spotted fever group rickettsiae (SFGR)-specific IgG were detected in 24 (39%) and 21 (34%) of 62 human serum samples, respectively, using indirect ELISAs, with six individuals seropositive for both. Only two (2%) Rattus rattus out of 86 small mammals presented antibodies against TGR. Out of 117 fleas collected from small mammals, Rickettsia typhi, a TGR, was detected in 26 Xenopsylla cheopis (24%) collected from rodents of an urban area (n = 107), while two of these urban X. cheopis (2%) were positive for Rickettsia felis, a SFGR. R. felis DNA was also detected in eight (31%) out of 26 Pulex irritans fleas.

Conclusions

The general population in Madagascar are exposed to rickettsiae, and two flea-associated Rickettsia pathogens, R. typhi and R. felis, are present near or in homes. Although our results are from a single district, they demonstrate that rickettsiae should be considered as potential agents of undifferentiated fever in Madagascar.

Clinical and laboratory characteristics, epidemiology, and outcomes of murine typhus: A systematic review

Murine or endemic typhus, a febrile disease caused by Rickettsia typhi, is often misdiagnosed due to its non-specific presentation. We sought to evaluate all available evidence in the literature regarding the clinical and laboratory manifestations, epidemiological characteristics, and outcomes of murine typhus. Pubmed was searched for all articles providing available data. In an effort to incorporate contemporary data, only studies from 1980 were included. Thirty-three case series including 2074 patients were included in final analysis. Available evidence suggests that the classic triad of fever, headache and rash is encountered in only one-third of patients. Other frequent symptoms were chills, malaise, myalgia, and anorexia. A tetrad of reported laboratory abnormalities consisting of elevated liver enzymes, lactate dehydrogenase, erythrocyte sedimentation rate and hypoalbuminemia was detected. Complications were observed in one-fourth of patients, reported mortality was extremely low, but untreated patients had notably longer duration of fever. Among epidemiological characteristics, a seasonal distribution with most cases reported during warmer months, was the most prominent finding. Murine typhus in children exhibits several different characteristics, with abdominal pain, diarrhea, and sore throat reported more commonly, higher frequency of anemia, lower frequency of hypoalbuminemia, hematuria and proteinuria and a much lower rate of complications. This systematic review of published evidence provides a thorough description of the clinical and laboratory features of murine typhus and highlights important differences in children.

Evidence of exposure to Rickettsia felis in Australian patients

Rickettsia felis is an emerging zoonosis, causing flea-borne spotted fever (FBSF). Serological diagnosis is typically confounded by cross-reactivity with typhus group rickettsiae and prior to the development of specific serological methods, cases of FBSF in Australia were misdiagnosed. Patient sera tested between August 2010 and December 2013 and known to be seropositive to R. typhi by immunofluorescence antibody testing (IFAT) were subsequently retested against R. felis using an R. felis-specific IFAT. Sera of 49 patients were of a sufficient quality to be included in re-analysis. A classification of FBSF and murine typhus (MT) was attributed to fourteen and seven patients respectively, based on a minimum four-fold higher antibody titre to R. felis than to R. typhi and vice versa. Twenty-eight patients were classified as indeterminate for either R. felis or R. typhi (antibody titres within two-fold of one another). Historically, it is likely that Australian patients clinically ill with FBSF were misdiagnosed. It is important that medical practitioners consider FBSF as part of their differential diagnoses, and obtain relevant history with regard to patient's exposure to domestic pets and their fleas. Australian microbiology diagnostic laboratories should include serological testing for R. felis as part of the diagnostic panel for febrile diseases. Veterinarians are encouraged to increase their awareness of this emerging zoonosis and advocate flea control in pets.

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.

[Macrophage activation syndrome: rare complication of murine typhus]

INTRODUCTION

Typhi is one of the rickettsial species endemic in the Mediterranean countries and is associated with the zoonotic infection of murine typhus, which may have a complicated course especially in adult patients. The association with macrophage activation syndrome (MAS) has rarely been reported in the medical literature.

CASE REPORT

We describe a case of murine typhus in a diabetic woman complicated with MAS, who was effectively treated with cyclin and parenteral immunoglobulin.

CONCLUSION

The murine typhus can be exceptionally complicated with SAM. This infection should be suspected in front of the discovery of SAM.

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.