Tularemia: an experience of 13 cases including a rare myocarditis in a referral center in Eastern Switzerland (Central Europe) and a review of the literature

Unusual pediatric lung infections: imaging findings

Pediatric lung infections continue to be a leading cause of pediatric morbidity and mortality. Although both pediatric and general radiologists are familiar with typical lung infections and their imaging findings in children, relatively rare lung infections continue to present a diagnostic challenge. In addition, the advances in radiological imaging and emergence of several new lung infections in recent years facilitated the need for up-to-date knowledge on this topic. In this review article, we discuss the imaging findings of pediatric lung infections caused by unusual/uncommon and new pathogens. We review the epidemiological, clinical, and radiological imaging findings of viral (coronavirus disease 2019, Middle East respiratory syndrome, bird flu), bacterial (Streptococcus anginosus, Francisella tularensis, Chlamydia psittaci), and parasitic lung infections (echinococcosis, paragonimiasis, amoebiasis). Additional disorders whose clinical course and imaging findings may mimic lung infections in children (hypersensitivity pneumonitis, pulmonary hemorrhage, eosinophilic pneumonia) are also presented, to aid in differential diagnosis. As the clinical presentation of children with new and unusual lung infections is often non-specific, imaging evaluation plays an important role in initial detection, follow-up for disease progression, and assessment of potential complications.

Identification of Francisella tularensis in ascites in the context of typhoidal tularaemia

Tularaemia is a highly infectious, zoonotic disease caused by Francisella tularensis, which has become increasingly prevalent over the past decade. Depending on the route of infection, different clinical manifestations can be observed. We report a case of typhoidal tularaemia presenting as a febrile illness with gastrointestinal symptoms in a patient in her mid-80s. During the acute illness phase and in the context of alcohol-related liver cirrhosis, the patient developed progressive ascites. During paracentesis, spontaneous bacterial peritonitis was consistently reported. Blood culture revealed Gram-negative bacilli identified as F. tularensis upon microscopic examination. Immediate clinical improvement was observed after adaptation to a pathogen-specific antibiotic regime. Typhoidal tularaemia presents general, non-specific symptoms without the local manifestations seen in other forms of the disease, thus representing a diagnostic challenge. In the case of protracted fever and if the epidemiological context as well as possible exposure are compatible, tularaemia should be considered in the differential diagnosis.

[Carcinoma, tuberculosis, atypical pneumonia - or may be pulmonary tularemia? Two case reports]

Tularemia is a rare zoonotic disease, endemic in rural areas all over Germany. It's clinical manifestation following inhalation of infectious aerosols may resemble pulmonary neoplasia, other atypical pneumonias or tuberculosis. Here we describe two representative cases with pulmonary tularemia.

Tularemia treatment: experimental and clinical data

Tularemia is a zoonosis caused by the Gram negative, facultative intracellular bacterium Francisella tularensis. This disease has multiple clinical presentations according to the route of infection, the virulence of the infecting bacterial strain, and the underlying medical condition of infected persons. Systemic infections (e.g., pneumonic and typhoidal form) and complications are rare but may be life threatening. Most people suffer from local infection (e.g., skin ulcer, conjunctivitis, or pharyngitis) with regional lymphadenopathy, which evolve to suppuration in about 30% of patients and a chronic course of infection. Current treatment recommendations have been established to manage acute infections in the context of a biological threat and do not consider the great variability of clinical situations. This review summarizes literature data on antibiotic efficacy against F. tularensis in vitro, in animal models, and in humans. Empirical treatment with beta-lactams, most macrolides, or anti-tuberculosis agents is usually ineffective. The aminoglycosides gentamicin and streptomycin remain the gold standard for severe infections, and the fluoroquinolones and doxycycline for infections of mild severity, although current data indicate the former are usually more effective. However, the antibiotic treatments reported in the literature are highly variable in their composition and duration depending on the clinical manifestations, the age and health status of the patient, the presence of complications, and the evolution of the disease. Many patients received several antibiotics in combination or successively. Whatever the antibiotic treatment administered, variable but high rates of treatment failures and relapses are still observed, especially in patients treated more then 2-3 weeks after disease onset. In these patients, surgical treatment is often necessary for cure, including drainage or removal of suppurative lymph nodes or other infectious foci. It is currently difficult to establish therapeutic recommendations, particularly due to lack of comparative randomized studies. However, we have attempted to summarize current knowledge through proposals for improving tularemia treatment which will have to be discussed by a group of experts. A major factor in improving the prognosis of patients with tularemia is the early administration of appropriate treatment, which requires better medical knowledge and diagnostic strategy of this disease.

Tularemia cases increase in the USA from 2011 through 2019

Tularemia is a rare but potentially serious bacterial zoonosis, which has been reported in the 47 contiguous states of the USA during 2001-2010. This report summarizes the passive surveillance data of tularemia cases reported to the Centers for Disease Control and Prevention from 2011 through 2019. There were 1984 cases reported in the USA during this period. The average national incidence was 0.07 cases per 100,000 person-years (PY), compared to 0.04 cases per 100,000 PY during 2001-2010. The highest statewide reported case 2011-2019 was in Arkansas (374 cases, 20.4% of total), followed by Missouri (13.1%), Oklahoma (11.9%), and Kansas (11.2%). Regarding race, ethnicity, and sex, tularemia cases were reported more frequently among white, non-Hispanic, and male patients. Cases were reported in all age groups; however, individuals 65 years-old and older exhibited the highest incidence. The seasonal distribution of cases generally paralleled the seasonality of tick activity and human outdoor activity, increasing during spring through mid-summer and decreasing through late summer and fall to winter lows. Improved surveillance and education of ticks and tick- and water-borne pathogens should play a key role in efforts to decrease the incidence of tularemia in the USA.

Water-borne oculoglandular tularemia: Two complicated cases and a review of the literature

BACKGROUND

In this study, we presented two cases of late diagnosed complicated oculoglandular tularemia and reviewed the clinical features of oculoglandular tularemia in cases reported in the last ten years.

METHOD

Tularemia was diagnosed when serum microagglutination test (MAT) was ≥ 1/160 titer or when there was at least a four-fold increase in MAT titers measured over a two-week interval. We searched the oculoglandular tularemia cases reported in the last 10 years in the PubMed and Google Academic engines.

RESULTS

Case 1 (19 M) and case 2 (15 M) had complaints of fever and burning in the eye. In both cases, the diagnosis of tularemia was delayed. Lymph node suppuration developed in both cases. A total of 19 cases of tularemia were found within the search. In the cases of oculoglandular tularemia reported in the last 10 years, submandibular and preauricular lymphadenopathy were most common after ocular findings and fever. The mean time to diagnosis was 41 ± 94 days, and the complication rate was 31.5%.

CONCLUSION

Tularemia should definitely be considered in cases of fever and ocular findings, especially in endemic areas. In non-endemic areas, a good anamnesis and clinical suspicion can help diagnose the disease early and reduce the complication rate.

Vector-Borne Tularemia: A Re-Emerging Cause of Cervical Lymphadenopathy

Tularemia is a zoonosis caused by the highly invasive bacterium Francisella tularensis. It is transmitted to humans by direct contact with infected animals or by vectors, such as ticks, mosquitos, and flies. Even though it is well-known as a tick-borne disease, it is usually not immediately recognised after a tick bite. In Slovenia, tularemia is rare, with 1-3 cases reported annually; however, the incidence seems to be increasing. Ulceroglandular tularemia is one of its most common forms, with cervical colliquative lymphadenopathy as a frequent manifestation. The diagnosis of tularemia largely relies on epidemiological information, clinical examination, imaging, and molecular studies. Physicians should consider this disease a differential diagnosis for a neck mass, especially after a tick bite, as its management significantly differs from that of other causes. Tularemia-associated lymphadenitis is treated with antibiotics and surgical drainage of the colliquated lymph nodes. Additionally, tularemia should be noted for its potential use in bioterrorism on behalf of the causative agents' low infectious dose, possible aerosol formation, no effective vaccine at disposal, and the ability to produce severe disease. This article reviews the recent literature on tularemia and presents a case of an adult male with tick-borne cervical ulceroglandular tularemia.

Development and evaluation of a rapid RPA/CRISPR-based detection of Francisella tularensis

Francisella tularensis is a dangerous pathogen that causes an extremely contagious zoonosis in humans named tularemia. Given its low-dose morbidity, the potential to be fatal, and aerosol spread, it is regarded as a severe threat to public health. The US Centers for Disease Control and Prevention (CDC) has classified it as a category A potential agent for bioterrorism and a Tier 1 Select Agent. Herein, we combined recombinase polymerase amplification (RPA) with CRISPR/Cas12a system to select the F. tularensis target gene (TUL4), creating a two-pronged rapid and ultrasensitive diagnostic method for detecting F. tularensis. The real-time RPA (RT-RPA) assay detected F. tularensis within 10 min at a sensitivity of 5 copies/reaction, F. tularensis genomic DNA of 5 fg, and F. tularensis of 2 × 102 CFU/ml; the RPA-CRISPR/Cas12a assay detects F. tularensis within 40 min at a sensitivity of 0.5 copies/reaction, F. tularensis genomic DNA of 1 fg, and F. tularensis of 2 CFU/ml. Furthermore, the evaluation of specificity showed that both assays were highly specific to F. tularensis. More importantly, in a test of prepared simulated blood and sewage samples, the RT-RPA assay results were consistent with RT-PCR assay results, and the RPA-CRISPR/Cas12a assay could detect a minute amount of F. tularensis genomic DNA (2.5 fg). There was no nonspecific detection with blood samples and sewage samples, giving the tests a high practical application value. For example, in on-site and epidemic areas, the RT-RPA was used for rapid screening and the RPA-CRISPR/Cas12a assay was used for more accurate diagnosis.

PEDIATRIC TULAREMIA– A CASE SERIES FROM A SINGLE CENTER IN SWITZERLAND

Background

The incidence of tularemia has recently increased throughout Europe. Pediatric tularemia typically presents with ulceroglandular or glandular disease and requires antimicrobial therapy not used in the empirical management of childhood acute lymphadenitis. We describe the clinical presentation and course in a case series comprising 20 patients.

Methods

This is a retrospective analysis of a single-center case series of microbiologically confirmed tularemia in patients <16 years of age diagnosed between 2010 and 2021.

Results

Nineteen patients (95%) presented with ulceroglandular (n = 14) or glandular disease (n = 5), respectively. A characteristic entry site lesion (eschar) was present in 14 (74%). Fever was present at illness onset in 15 patients (75%) and disappeared in all patients before targeted therapy was initiated. The diagnosis was confirmed by serology in 18 patients (90%). While immunochromatography was positive as early as on day 7, a microagglutination test titer 1:≥160 was found no earlier than on day 13. Sixteen patients (80%) were initially treated with an antimicrobial agent ineffective against F. tularensis. The median delay (range) from illness onset to initiation of targeted therapy was 12 (6–40) days. Surgical incision and drainage were ultimately performed in 12 patients (60%).

Conclusions

Pediatric tularemia in Switzerland usually presents with early, self-limiting fever and a characteristic entry site lesion with regional lymphadenopathy draining the scalp or legs. Particularly in association with a tick exposure history, this presentation may allow early first-line therapy with an agent specifically targeting F. tularensis, potentially obviating the need for surgical therapy.

Host Immunity and Francisella tularensis: A Review of Tularemia in Immunocompromised Patients

Tularemia, caused by the bacterium Francisella tularensis, is an infrequent zoonotic infection, well known in immunocompetent (but poorly described in immunocompromised) patients. Although there is no clear literature data about the specific characteristics of this disease in immunocompromised patients, clinical reports seem to describe a different presentation of tularemia in these patients. Moreover, atypical clinical presentations added to the fastidiousness of pathogen identification seem to be responsible for a delayed diagnosis, leading to a” loss of chance” for immunocompromised patients. In this article, we first provide an overview of the host immune responses to Francisella infections and discuss how immunosuppressive therapies or diseases can lead to a higher susceptibility to tularemia. Then, we describe the particular clinical patterns of tularemia in immunocompromised patients from the literature. We also provide hints of an alternative diagnostic strategy regarding these patients. In conclusion, tularemia should be considered in immunocompromised patients presenting pulmonary symptoms or unexplained fever. Molecular techniques on pathological tissues might improve diagnosis with faster results.

Tularemia: A Case Series of Patients Diagnosed at the National Reference Center for Rickettsioses From 2008 to 2017

BACKGROUND

We describe the epidemiological, clinical, and prognostic aspects of 177 tularemia cases diagnosed at the National Reference Center for rickettsioses, coxiellosis, and bartonelloses between 2008 and 2017.

METHODS

All patients with a microbiological diagnosis of tularemia made in the laboratory were included. Clinical and epidemiological data were collected retrospectively from clinicians in charge of patients using a standardized questionnaire. Diagnostic methods used were indirect immunofluorescence serology, real-time polymerase chain reaction (PCR), and universal PCR targeting the 16S ribosomal ribonucleic acid gene.

RESULTS

The series included 54 females and 123 males (sex ratio, 2.28; mean age, 47.38 years). Eighty-nine (50.2%) were confirmed as having tularemia on the basis of a positive Francisella tularensis PCR or seroconversion, and 88 (49.8%) were considered as probable due to a single positive serum. The regions of France that were most affected included Pays de la Loire (22% of cases), Nouvelle Aquitaine (18.6% of cases), and Grand Est (12.4% of cases). Patients became infected mainly through contact with rodents or game (38 cases, 21.4%), through tick-bites (23 cases, 12.9%), or during outdoor leisure activities (37 cases, 20.9%). Glandular and ulceroglandular forms were the most frequent (109 cases, 61.5%). Two aortitis, an infectious endocarditis, a myocarditis, an osteoarticular infection, and a splenic hematoma were also diagnosed. Tularemia was discovered incidentally in 54.8% of cases. Seventy-eight patients were hospitalized, and no deaths were reported.

CONCLUSIONS

Our data suggest that in an endemic area and/or in certain epidemiological contexts, tularemia should be sought to allow an optimized antibiotic therapy and a faster recovery.

Parinaud's Oculoglandular Syndrome: A Case in an Adult with Flea-Borne Typhus and a Review

Parinaud's oculoglandular syndrome (POGS) is defined as unilateral granulomatous conjunctivitis and facial lymphadenopathy. The aims of the current study are to describe a case of POGS with uveitis due to flea-borne typhus (FBT) and to present a diagnostic and therapeutic approach to POGS. The patient, a 38-year old man, presented with persistent unilateral eye pain, fever, rash, preauricular and submandibular lymphadenopathy, and laboratory findings of FBT: hyponatremia, elevated transaminase and lactate dehydrogenase levels, thrombocytopenia, and hypoalbuminemia. His condition rapidly improved after starting doxycycline. Soon after hospitalization, he was diagnosed with uveitis, which responded to topical prednisolone. To derive a diagnostic and empiric therapeutic approach to POGS, we reviewed the cases of POGS from its various causes since 1976 to discern epidemiologic clues and determine successful diagnostic techniques and therapies; we found multiple cases due to cat scratch disease (CSD; due to Bartonella henselae) (twelve), tularemia (ten), sporotrichosis (three), Rickettsia conorii (three), R. typhi/felis (two), and herpes simplex virus (two) and single cases due to tuberculosis, paracoccidioidomycosis, Yersinia enterocolitica, Pasteurella multocida, Chlamydia trachomatis, Epstein-Barr virus, and Nocardia brasiliensis. Preauricular lymphadenopathy is a common clinical clue for POGS and is unusual in viral and bacterial conjunctivitis. For POGS, the major etiological consideration is B. henselae, which is usually diagnosed by the indirect immunofluorescence serologic technique. Although CSD POGS is usually self-limited, oral azithromycin may hasten resolution. However, other possible etiologies of POGS may also arise from cat or cat flea contact: sporotrichosis, tularemia, Pasteurella multocida, or FBT. If there is no cat contact, other epidemiologic and clinical findings should be sought, because several of these conditions, such as tularemia, paracoccidioidomycosis, and tuberculosis, may have grave systemic complications. Although there are usually no long-term ocular sequelae if POGS is properly diagnosed, it still may cause prolonged ocular discomfort and require multiple physician contacts.

The clinical spectrum of tularemia-Two cases

We report two cases of tularemia with different clinical manifestations, both suspected of tick-borne transmission and with near-complete remission of all symptoms within 3 months after antimicrobial treatment. The first patient presented with a classical ulceroglandular manifestation; general malaise, an ulcer and lymphadenopathy, occurring two weeks after a tick bite. Diagnosis was established by polymerase chain reaction of a skin biopsy from the ulcer. The second patient presented with a rare systemic manifestation including bacteremia and myocarditis resulting in severe clinical heart failure, pulmonary edema and secondary kidney failure. Previous tick bites were elucidated after the bacteremia was discovered. The cases underscore the heterogeneity of manifestations, the diagnostic approach and the importance of thorough medical history including recent exposures especially in cases with infection of unknown origin.

Francisella tularensis as the cause of protracted fever

BACKGROUND

Tularemia, a re-emerging, potential life threatening infectious disease, can present itself with nonspecific clinical symptoms including fever, chills and malaise. Taking a detailed history of exposure and a highly raised index of clinical suspicion are necessary to take the appropriate diagnostic and therapeutic steps in this setting. Here, a case report of typhoid tularaemia is presented.

CASE PRESENTATION

A 53-year old male forester and farmer with protracted fever, abdominal pain, diarrhoea and loss of weight, who experienced productive cough and a pulmonary infiltrate later in the course of disease, was admitted for further investigation. Tularaemia was suspected only owing to history and confirmed by serologic testing more than three weeks after the beginning of the symptoms. The initial antibiotic therapy with ceftriaxone/doxycycline was switched to ciprofloxacin, resulting in the resolution of fever and symptoms.

CONCLUSION

Tularaemia has to be considered as a differential diagnosis in febrile patients, even more in cases with protracted fever. Since tularaemia is expanding geographically, involving more animal hosts and causing larger outbreaks, clinicians have to be aware of this potentially fatal disease.

Tick-Borne Illness and Infective Endocarditis: A Rare Case of Tularemia

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Francisella tularensis infection, or tularemia, can cause infective endocarditis.

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Echocardiographic data are critical in prompt diagnosis of this rare clinical entity.

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Accurate diagnosis requires a high index of suspicion in the correct clinical context.