Evaluation of tularaemia courses: a multicentre study from Turkey

The Epidemiological Investigation of Yersinia pestis, Francisella tularensis, and Arenavirus Infections in Small Mammals in Northwestern Iran

Background: The control and prevention of rodent-borne diseases are mainly based on our knowledge of ecology and the infectious status of their reservoir hosts. This study aimed to evaluate the prevalence of Francisella tularensis, Yersinia pestis, and arenavirus infections in small mammals and to assess the potential of disease occurrence in East Azerbaijan, northwest of Iran, in 2017 and 2018. Methods: Spleen and lung samples were obtained from all trapped small mammals. The real-time quantitative PCR (qPCR) method was used to detect nucleic acid sequences of F. tularensis, Y. pestis, and arenaviruses. Serum samples were tested for antibodies indicating the host response to F. tularensis and Y. pestis infections using the standard tube agglutination test and enzyme-linked immunosorbent assay (ELISA), respectively. Results: A total of 205 rodents, four Eulipotyphla, and one carnivore were captured. The most common rodent species captured (123 of 205 rodents, 60%) belonged to the genus Meriones (mainly Persian jird, Meriones persicus). In total, 317 fleas were removed from trapped animals. Flea species belonged to Xenopsylla buxtoni, Xenopsylla nuttalli, Stenoponia tripectinata, Paraceras melis, Ctenophthalmus rettigi smiti, Rhadinopsylla bivirgis, Paradoxopsyllus grenieri, and Nosopsyllus iranus. Using the qPCR tests, five spleen samples from M. persicus were positive for F. tularensis. The qPCR tests were negative for the detection of Y. pestis and arenaviruses. Finally, all serum samples tested were negative for antibodies against Y. pestis and F. tularensis. Conclusions: F. tularensis was the only zoonotic agent detected in rodents captured in East Azerbaijan. However, the diversity of trapped rodents and fleas provides the potential for the spread of various rodent-borne viral and bacterial diseases in the studied areas.

Characterization of tularemia foci in the Republic of Kazakhstan from 2000 to 2020

The wide distribution of tularemia in the territory of Kazakhstan is associated with landscape and geographical characteristics. This is explained by a combination of natural factors: the presence of certain types of rodents-reservoirs and sources, ectoparasites-carriers of the causative agent of tularemia. The study of the current spatial and temporal characterization of tularemia in Kazakhstan from 2000 to 2020 will determine the epidemiological status of tularemia and improve the monitoring system in Kazakhstan. In this work we demonstrated the results of a retrospective survey of natural foci of tularemia: analysis of vector, small mammal and human data. The spatial and temporal characteristics of tularemia from 2000 to 2020 in the territory of Kazakhstan were studied in comparison with historical data, including the description of tularemia outbreaks, the clinical picture, and the source of infection, transmission factors, and geographical coordinates of outbreak registration. Sampling was carried out by trapping rodents on snap traps and collecting ticks by rodent combing and by "flagging" methods. For the last 20 years, 85 human cases of tularemia have been reported. During the period from 2000 to 2020, more than 600 strains of F. tularensis were isolated from field rodents and ticks in the natural foci of tularemia. MLVA typing of F. tularensis strains isolated from natural foci of tularemia in Kazakhstan over the past 20 years. The results of retrospective monitoring indicate that currently active foci of tularemia include the Aktobe, West Kazakhstan, Almaty, East Kazakhstan, and Pavlodar regions. Low-activity natural foci are located in the territory of the Akmola, Karaganda, North Kazakhstan, Kostanay, Atyrau, Zhambyl, and Kyzylorda regions. There are no active natural foci of tularemia in the Mangystau and Turkestan regions. The widespread occurrence of tularemia in the country is associated with landscape and geographical features that contribute to the circulation of the pathogen in the natural focus. An analysis of natural foci of tularemia showed that it is necessary to continue monitoring studies of carriers and vectors for the presence of the causative agent of the F. tularensis, in order to prevent mass cases of human disease.

Treatment Outcome of Severe Respiratory Type B Tularemia Using Fluoroquinolones

BACKGROUND

Fluoroquinolones lack approval for treatment of tularemia but have been used extensively for milder illness. Here, we evaluated fluoroquinolones for severe illness.

METHODS

In an observational study, we identified case-patients with respiratory tularemia from July to November 2010 in Jämtland County, Sweden. We defined severe tularemia by hospitalization for >24 hours and severe bacteremic tularemia by Francisella tularensis subsp. holarctica growth in blood or pleural fluid. Clinical data and drug dosing were retrieved from electronic medical records. Chest images were reexamined. We used Kaplan-Meier curves to evaluate time to defervescence and hospital discharge.

RESULTS

Among 67 case-patients (median age, 66 years; 81% males) 30-day mortality was 1.5% (1 of 67). Among 33 hospitalized persons (median age, 71 years; 82% males), 23 had nonbacteremic and 10 had bacteremic severe tularemia. Subpleural round consolidations, mediastinal lymphadenopathy, and unilateral pleural fluid were common on chest computed tomography. Among 29 hospitalized persons with complete outcome data, ciprofloxacin/levofloxacin (n = 12), ciprofloxacin/levofloxacin combinations with doxycycline and/or gentamicin (n = 11), or doxycycline as the single drug (n = 6) was used for treatment. One disease relapse occurred with doxycycline treatment. Treatment responses were rapid, with median fever duration 41.0 hours in nonbacteremic and 115.0 hours in bacteremic tularemia. Increased age-adjusted Charlson comorbidity index predicted severe bacteremic tularemia (odds ratio, 2.7 per score-point; 95% confidence interval, 1.35-5.41). A 78-year-old male with comorbidities and delayed ciprofloxacin/gentamicin treatment died.

CONCLUSIONS

Fluoroquinolone treatment is effective for severe tularemia. Subpleural round consolidations and mediastinal lymphadenopathy were typical findings on computed tomography among case-patients in this study.

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.

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 and zoonotic infections and their relationships with regional and socioeconomic statuses: An ID-IRI survey in 24 countries of Europe, Africa and Asia

BACKGROUND

In this cross-sectional, international study, we aimed to analyze vector-borne and zoonotic infections (VBZI), which are significant global threats.

METHOD

VBZIs' data between May 20-28, 2018 was collected. The 24 Participatingcountries were classified as lower-middle, upper-middle, and high-income.

RESULTS

382 patients were included. 175(45.8%) were hospitalized, most commonly in Croatia, Egypt, and Romania(P = 0.001). There was a significant difference between distributions of VBZIs according to geographical regions(P < 0.001). Amebiasis, Ancylostomiasis, Blastocystosis, Cryptosporidiosis, Giardiasis, Toxoplasmosis were significantly more common in the Middle-East while Bartonellosis, Borreliosis, Cat Scratch Disease, Hantavirus syndrome, Rickettsiosis, Campylobacteriosis, Salmonellosis in Central/East/South-East Europe; Brucellosis and Echinococcosis in Central/West Asia; Campylobacteriosis, Chikungunya, Tick-borne encephalitis, Visceral Leishmaniasis, Salmonellosis, Toxoplasmosis in the North-Mediterranean; CCHF, Cutaneous Leishmaniasis, Dengue, Malaria, Taeniasis, Salmonellosis in Indian Subcontinent; Lassa Fever in West Africa. There were significant regional differences for viral hemorrhagic fevers(P < 0.001) and tick-borne infections(P < 0.001), and according to economic status for VBZIs(P < 0.001). The prevalences of VBZIs were significantly higher in lower-middle income countries(P = 0.001). The most similar regions were the Indian Subcontinent and the Middle-East, the Indian Subcontinent and the North-Mediterranean, and the Middle-East and North-Mediterranean regions.

CONCLUSIONS

Regional and socioeconomic heterogeneity still exists for VBZIs. Control and eradication of VBZIs require evidence-based surveillance data, and multidisciplinary efforts.

Tularemia: a re-emerging tick-borne infectious disease

Tularemia is a bacterial disease of humans, wild, and domestic animals. Francisella tularensis, which is a Gram-negative coccobacillus-shaped bacterium, is the causative agent of tularemia. Recently, an increase in the number of human tularemia cases has been noticed in several countries around the world. It has been reported mostly from North America, several Scandinavian countries, and certain Asian countries. The disease spreads through vectors such as mosquitoes, horseflies, deer flies, and ticks. Humans can acquire the disease through direct contact of sick animals, consumption of infected animals, drinking or direct contact of contaminated water, and inhalation of bacteria-loaded aerosols. Low infectious dose, aerosol route of infection, and its ability to induce fatal disease make it a potential agent of biological warfare. Tularemia leads to several clinical forms, such as glandular, ulceroglandular, oculoglandular, oropharyngeal, respiratory, and typhoidal forms. The disease is diagnosed through the use of culture, serology, or molecular methods. Quinolones, tetracyclines, or aminoglycosides are frequently used in the treatment of tularemia. No licensed vaccine is available in the prophylaxis of tularemia and this is need of the time and high-priority research area. This review mostly focuses on general features, importance, current status, and preventive measures of this disease.

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.

Early Diagnosis of Tularemia by Flow Cytometry, Czech Republic, 2003-20151

We retrospectively assessed the utility of a flow cytometry–based test quantifying the percentage of CD3+ T cells with the CD4–/CD8– phenotype for predicting tularemia diagnoses in 64 probable and confirmed tularemia patients treated during 2003–2015 and 342 controls with tularemia-like illnesses treated during 2012–2015 in the Czech Republic. The median percentage of CD3+/CD4–/CD8– T cells in peripheral blood was higher in tularemia patients (19%, 95% CI 17%–22%) than in controls (3%, 95% CI 2%–3%). When we used 8% as the cutoff, this test’s sensitivity was 0.953 and specificity 0.895 for distinguishing cases from controls. The CD3+/CD4–/CD8– T cells increased a median of 7 days before tularemia serologic test results became positive. This test supports early presumptive diagnosis of tularemia for clinically suspected cases 7–14 days before diagnosis can be confirmed by serologic testing in regions with low prevalences of tularemia-like illnesses.

Francisella tularensis Periprosthetic Joint Infections Diagnosed with Growth in Cultures

Tularemia caused by Francisella tularensis is a zoonotic infection of the Northern Hemisphere that mainly affects the skin, lymph nodes, bloodstream, and lungs. Other manifestations of tularemia are very rare, especially those with musculoskeletal involvement. Presenting in 2016, we diagnosed two cases of periprosthetic knee joint infections (PJI) caused by Francisella tularensis in Europe (one in Switzerland and one in the Czech Republic). We found only two other PJI cases in the literature, another knee PJI diagnosed 1999 in Ontario, Canada, and one hip PJI in Illinois, USA, in 2017. Diagnosis was made in all cases by positive microbiological cultures after 3, 4, 7, and 12 days. All were successfully treated, two cases by exchange of the prosthesis, one with debridement and retention, and one with repeated aspiration of the synovial fluid only. Antibiotic treatment was given between 3 weeks and 12 months with either ciprofloxacin-rifampin or with doxycycline alone or doxycycline in combination with gentamicin. Zoonotic infections should be considered in periprosthetic infections in particular in culture-negative PJIs with a positive histology or highly elevated leukocyte levels in synovial aspiration. Here, we recommend prolonging cultivation time up to 14 days, performing specific PCR tests, and/or conducting epidemiologically appropriate serological tests for zoonotic infections, including that for F. tularensis.

Epidemiological features of tularaemia in Central Anatolia, Turkey

Tularaemia has become a public health threat in Turkey. Our aim was to examine the epidemiological characteristics of 154 tularaemia cases reported from Kayseri, Central Anatolia, between 2010 and 2017. Clinical diagnosis was confirmed by micro-agglutination test (≥1/160 titres). Most patients (56.5%) were residing in rural areas. The year with the highest case load was 2011 (40% of all cases). Tularaemia was reported in all seasons, but mostly in February (26.1%). Morbidity rates were higher in women and people aged ≥65 years. The tularaemia incidence in Kayseri was higher than in the whole country between 2011 and 2016, though after the initial outbreak between 2010 and 2012, it seems to have become less frequent.

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

BACKGROUND

Tularemia, a zoonotic disease caused by Francisella tularensis, can cause a broad spectrum of disease in humans including six major clinical presentations: the ulceroglandular, glandular, oculoglandular, oropharyngeal, typhoidal and pneumonic form. The epidemiology and ecology and thus transmission of tularemia are complex, depending on conditions unique to specific locations.

CASE SERIES AND METHODS

Thirteen cases with different forms of the disease and one very rare case of a myocarditis are reported, discussed, and reviewed within the scope of current literature.

CONCLUSION

Tularemia is a rare, but emerging disease in Central Europe with glandular and ulceroglandular disease as its predominant forms. Transmission is mainly caused by contact with lagomorphs, rodents and tick bites. However, domestic cats may play an important role in transmission too. Myocarditis is probably a worldwide, but very rare manifestation of tularemia.

Coinfections identified from metagenomic analysis of cervical lymph nodes from tularemia patients

BACKGROUND

Underlying coinfections may complicate infectious disease states but commonly go unnoticed because an a priori clinical suspicion is usually required so they can be detected via targeted diagnostic tools. Shotgun metagenomics is a broad diagnostic tool that can be useful for identifying multiple microbes simultaneously especially if coupled with lymph node aspirates, a clinical matrix known to house disparate pathogens. The objective of this study was to analyze the utility of this unconventional diagnostic approach (shotgun metagenomics) using clinical samples from human tularemia cases as a test model. Tularemia, caused by the bacterium Francisella tularensis, is an emerging infectious disease in Turkey. This disease commonly manifests as swelling of the lymph nodes nearest to the entry of infection. Because swollen cervical nodes are observed from many different types of human infections we used these clinical sample types to analyze the utility of shotgun metagenomics.

METHODS

We conducted an unbiased molecular survey using shotgun metagenomics sequencing of DNA extracts from fine-needle aspirates of neck lymph nodes from eight tularemia patients who displayed protracted symptoms. The resulting metagenomics data were searched for microbial sequences (bacterial and viral).

RESULTS

F. tularensis sequences were detected in all samples. In addition, we detected DNA of other known pathogens in three patients. Both Hepatitis B virus (HBV) and Human Parvovirus B-19 were detected in one individual and Human Parvovirus B-19 alone was detected in two other individuals. Subsequent PCR coupled with Sanger sequencing verified the metagenomics results. The HBV status was independently confirmed via serological diagnostics, despite evading notice during the initial assessment.

CONCLUSION

Our data highlight that shotgun metagenomics of fine-needle lymph node aspirates is a promising clinical diagnostic strategy to identify coinfections. Given the feasibility of the diagnostic approach demonstrated here, further steps to promote integration of this type of diagnostic capability into mainstream clinical practice are warranted.

Molecular Survey of Tularemia and Plague in Small Mammals From Iran

Introduction: Plague and tularemia are zoonoses and their causative bacteria are circulating in certain regions of Iran. This study was conducted to investigate potential disease reservoirs amongst small wildlife species in different regions of Iran.

Methods: Rodents, insectivores and hares from 17 different provinces of the country were collected in 2014 and 2015. Samples were taken from the spleens of the animals and Real-time PCR was applied to detect nucleic acid sequences that are specific to Francisella tularensis and Yersinia pestis, respectively.

Results: Among 140 collected rodents, 25 distinct species were identified out of which five were the most common: Microtus paradoxus (21% out of 140 rodents), Apodemus witherbyi (12%), Microtus irani (11%), Mus musculus (11%) and Microtus socialis (10%). Seventeen insectivores were collected and identified as Crocidura suaveolens (82%) and C. leucodon (18%). Fifty-one hares were collected and identified as Lepus europaeus (57%), Lepus tolai (14%) and Lepus sp. (29%). Three out of 140 explored rodents (1.91%) were positive for F. tularensis, an A. witherbyi, a Mus musculus domesticus, and a Chionomys nivalis collected from Golestan, Khuzestan and Razavi Khorasan provinces, respectively. Two hares (3.92%) were F. tularensis-positive, a L. europaeus from Khuzestan and a Lepus sp. from the Sistan and Baluchistan province. None of the tested animals were positive for Y. pestis.

Conclusion: This is the first report of direct detection of F. tularensis in mammals of Iran and the first-time observation of the agent in a snow vole, C. nivalis worldwide. The results indicate that tularemia is more widespread in Iran than previously reported including the Northeast and Southwestern parts of the country. Future studies should address genetic characterization of F. tularensis positive DNA samples from Iran to achieve molecular subtyping and rule out assay cross-reactivity with near neighbor Francisella species.

Dermatological aspects of tularaemia: a study of 168 cases

BACKGROUND

Tularaemia is a zoonotic infectious disease caused by Francisella tularensis, an aerobic, uncapsulated, gram-negative coccobacillus. Several case reports have appeared on the dermatological manifestations of tularaemia, but relatively few longer-term studies are available.

AIM

To identify skin features of tularaemia that aid in its diagnosis.

METHODS

In total, 168 patients (68 male, 100 female) diagnosed with tularaemia were retrospectively examined. All dermatological data for these patients were evaluated.

RESULTS

Of the 168 patients, 149 (88.69%) had tularaemia of the oropharyngeal type, 12 (7.73%) had the ulceroglandular type, 5 (2.9%) had the oculoglandular type and 2 (0.59%) had the pulmonary type. Secondary skin manifestations were found in 26 patients (15.47%). Sweet syndrome (SS) was found in 11 patients (6.54%), most of whom presented with the oropharyngeal form, while erythema nodosum (EN) was found in 7 patients (4.16%), dermatitis in 2 (1.19%), urticaria in 2 (1.19%), acneiform eruptions in 1 (0.59%), vasculitis-like eruptions in 1 (0.59%) and SS + EN in 1 (0.59%). Patients with the oropharyngeal form had a statistically significant (P < 0.001) higher number of skin findings than patients with the other forms.

CONCLUSIONS

In clinical practice, tularaemia may present with various cutaneous manifestations, and dermatologists who work in endemic regions must be aware of the possibility of this disease.

Francisella tularensis Susceptibility to Antibiotics: A Comprehensive Review of the Data Obtained In vitro and in Animal Models

The antibiotic classes that are recommended for tularaemia treatment are the aminoglycosides, the fluoroquinolones and the tetracyclines. However, cure rates vary between 60 and 100% depending on the antibiotic used, the time to appropriate antibiotic therapy setup and its duration, and the presence of complications, such as lymph node suppuration. Thus, antibiotic susceptibility testing (AST) of F. tularensis strains remains of primary importance for detection of the emergence of antibiotic resistances to first-line drugs, and to test new therapeutic alternatives. However, the AST methods reported in the literature were poorly standardized between studies and AST data have not been previously evaluated in a comprehensive and comparative way. The aim of the present review was to summarize experimental data on antibiotic susceptibilities of F. tularensis obtained in acellular media, cell models and animal models since the introduction of fluoroquinolones in the treatment of tularaemia in 1989. We compiled MIC data of 33 antibiotics (including aminoglycosides, fluoroquinolones, tetracyclines, macrolides, β-lactams, chloramphenicol, rifampicin, and linezolid) against 900 F. tularensis strains (504 human strains), including 107 subsp. tularensis (type A), 789 subsp. holarctica (type B) and four subsp. mediasiatica strains, using various AST methods. Specific culture media were identified or confirmed as unsuitable for AST of F. tularensis. Overall, MICs were the lowest for ciprofloxacin (≤ 0.002-0.125 mg/L) and levofloxacin, and ranged from ≤ 0.016 to 2 mg/L for gentamicin, and 0.064 to 4 mg/L for doxycycline. No resistant strain to any of these antibiotics was reported. Fluoroquinolones also exhibited a bactericidal activity against intracellular F. tularensis and lower relapse rates in animal models when compared with the bacteriostatic compound doxycycline. As expected, lower MIC values were found for macrolides against type A and biovar I type B strains, compared to biovar II type B strains. The macrolides were more effective against F. tularensis grown in phagocytic cells than in acellular media.

A Field Study of Plague and Tularemia in Rodents, Western Iran

INTRODUCTION

Kurdistan Province in Iran is a historical focus for plague and tularemia. This study aimed at assessing the current status of these two foci by studying their rodent reservoirs.

MATERIALS AND METHODS

Rodents were trapped and their ectoparasites were collected. The genus and species of both rodents and ectoparasites were determined. Serological analyses of rodent blood samples were done by enzyme-linked immunosorbent assay for plague and by standard tube agglutination assay for tularemia. Rodent spleen samples were subjected to bacterial culture, microscopic examination, and real-time PCR to search for active plague or tularemia infection.

RESULTS

During this study, 245 rodents were trapped, of which the most abundant genera were Apodemus (40%), Mus (24.49%), and Meriones (12.65%). One hundred fifty-three fleas, 37 mites, and 54 ticks were collected on these rodents. The results of all direct and indirect tests were negative for plague. Serological tests were positive for tularemia in 4.8% of trapped rodents.

DISCUSSION

This study is the first report on the presence of tularemia infection in rodents in Western Iran. Since Meriones persicus is a known reservoir for plague and tularemia, and this rodent carried plague and tularemia vectors in Marivan and Sanandaj districts, there is a real potential for the occurrence of these two diseases in this region.

Imaging Findings of Ulceroglandular Tularemia

Francisella tularensis, the causative organism in Tularemia, is a relatively rare disease. There are a few radiological clues to elucidate its presence when suspicion arises. There should be strong consideration for Tularemia in the differential of any patient with its classic symptoms, diffuse cervical lymphadenopathy with evidence of necrosis, and enlarged adenoids. Ultrasound may demonstrate suppurative lymphadenopathy suggestive of infection, as in the case presented. CT often will demonstrate the extent of lymphadenopathy. On chest radiography, tularemia pneumonia is often the presenting finding, which may demonstrate bilateral or lobar infiltrates. Additionally, hilar lymphadenopathy and pleural effusions are often associated findings. Cavitary lesions may be present, which are better delineated on CT scan. We present a case of a 7-year-old male who presented with a painful right-sided palpable neck mass for 9 days, who was diagnosed with Tularemia after numerous admissions.

Ultrasonography and contrast-enhanced CT findings of tularemia in the neck

PURPOSE

We aimed to evaluate the ultrasonography (US) and contrast-enhanced computed tomography (CECT) findings of tularemia in the neck.

METHODS

US and CECT findings of 58 patients with serologically proven tularemia were retrospectively evaluated. Forty-eight patients underwent US and 42 patients underwent CECT. Lymph node characteristics and parotid preauricular region involvement were analyzed using US and CECT. In addition, involvement of larynx, oropharynx, and retropharynx; presence of periorbital edema; and neck abscess formation were evaluated using CECT. Fine needle aspiration cytology (FNAC) results of enlarged lymph nodes were analyzed in 29 patients.

RESULTS

Hypoechoic pattern, round shape, absence of hilum, and cystic necrosis were seen in most of the lymph nodes especially at level 2 and 3 on US and CECT. Matting was more commonly observed than irregular nodal border on US and CECT. Parotid preauricular region involvement was seen in 20.8% of patients on US. Oropharyngeal, retropharyngeal, laryngeal and parotid preauricular region involvement and periorbital edema were seen in 52.4%, 19.1%, 4.8%, 31%, and 9.5% of tularemia patients, respectively. Neck abscess was found in 59.5% of patients on CECT. Suppurative inflammation was the most common finding of FNAC.

CONCLUSION

Tularemia should be considered in the presence of level 2 and 3 lymph nodes with cystic necrosis, matting, absence of calcification, oropharyngeal and retropharyngeal region involvement, and neck abscess, particularly in endemic areas.

Water as Source of Francisella tularensis Infection in Humans, Turkey

Francisella tularensis DNA extractions and isolates from the environment and humans were genetically characterized to elucidate environmental sources that cause human tularemia in Turkey. Extensive genetic diversity consistent with genotypes from human outbreaks was identified in environmental samples and confirmed water as a source of human tularemia in Turkey.

An overview: tularemia and travel medicine

Tularemia is a bacterial zoonotic infection. The disease is endemic in most parts of the world, has been reported through the northern hemisphere between 30 and 71° N latitude. Francisella tularensis causes infection in a wide range of vertebrates (rodents, lagomorphs) and invertebrates (ticks, mosquitoes and other arthropods). Humans can acquire this infection through several routes including; a bite from an infected tick, deerfly or mosquito, contact with an infected animal or its dead body. It can also be spread to human by drinking contaminated water or breathing contaminated dirt or aerosol. Clinical manifestation of this disease varies depending on the biotype, inoculum and port of entry. Infection is potentially life threatening, but can effectively be treated with antibiotics. Travelers visiting rural and agricultural areas in endemic countries may be at greater risk. Appropriate clothing and use of insect repellants is essential to prevent tick borne illness. Travelers also should be aware of food and waterborne disease; avoid consuming potentially contaminated water and uncooked meat. Physicians should be aware of any clinical presentation of tularemia in the patients returning from endemic areas.