Review

Authors: Jill Ellis, Petra C F Oyston, Michael Green...

Francisella tularensis is the etiological agent of tularemia, a serious and occasionally fatal disease of humans and animals. In humans, ulceroglandular tularemia is the most common form of the disease and is usually a consequence of a bite from an arthropod vector which has previously fed on an infected animal. The pneumonic form of the disease occurs rarely but is the likely form of the disease should this bacterium be used as a bioterrorism agent. The diagnosis of disease is not straightforward. F. tularensis is difficult to culture, and the handling of this bacterium poses a significant risk of infection to laboratory personnel. Enzyme-linked immunosorbent assay- and PCR-based methods have been used to detect bacteria in clinical samples, but these methods have not been adequately evaluated for the diagnosis of pneumonic tularemia. Little is known about the virulence mechanisms of F. tularensis, though there is a large body of evidence indicating that it is an intracellular pathogen, surviving mainly in macrophages. An unlicensed live attenuated vaccine is available, which does appear to offer protection against ulceroglandular and pneumonic tularemia. Although an improved vaccine against tularemia is highly desirable, attempts to devise such a vaccine have been limited by the inability to construct defined allelic replacement mutants and by the lack of information on the mechanisms of virulence of F. tularensis. In the absence of a licensed vaccine, aminoglycoside antibiotics play a key role in the prevention and treatment of tularemia.

Topics: Animals; Bacterial Vaccines; Disease Models, Animal; Francisella tularensis; Gene Expression Regulation, Bacterial; Humans; Tularemia; Virulence

PubMed: 12364373
DOI: 10.1128/CMR.15.4.631-646.2002

Review

Authors: Manon Degabriel, Stanimira Valeva, Sandrine Boisset...

Tularaemia is a zoonotic disease caused by the Gram-negative bacterium, . Depending on its entry route into the organism, causes different diseases, ranging from life-threatening pneumonia to less severe ulceroglandular tularaemia. Various strains with different geographical distributions exhibit different levels of virulence. is an intracellular bacterium that replicates primarily in the cytosol of the phagocytes. The main virulence attribute of is the type 6 secretion system (T6SS) and its effectors that promote escape from the phagosome. In addition, has evolved a peculiar envelope that allows it to escape detection by the immune system. In this review, we cover tularaemia, different strains, and their pathogenicity. We particularly emphasize the intracellular life cycle, associated virulence factors, and metabolic adaptations. Finally, we present how largely escapes immune detection to be one of the most infectious and lethal bacterial pathogens.

Topics: Humans; Francisella tularensis; Virulence; Tularemia; Virulence Factors; Phagosomes

PubMed: 37941380
DOI: 10.1080/21505594.2023.2274638

Review

Authors: Katherine Anne Feldman

Tularemia is a rare but potentially fatal disease that develops in numerous wild and domestic animals, including lagomorphs, rodents, cats, and humans. The disease occurs throughout much of the United States and should be considered in the differential diagnosis of acute febrile illness, particularly when risk factors such as contact with wild mammals or tick exposure are present. Veterinarians may be at increased risk of acquiring tularemia from contact with infected animals, but standard precautions should greatly reduce this risk. Outbreaks of tularemia warrant investigation, especially given the possibility of the use of F tularensis as an agent of bioterrorism.

Topics: Animals; Animals, Domestic; Animals, Wild; Diagnosis, Differential; Humans; Prognosis; Public Health; Tularemia; United States; Zoonoses

PubMed: 12675294
DOI: 10.2460/javma.2003.222.725

Authors: Astrid Kravdal, Øystein Olav Stubhaug, Ruta Piekuviene...

BACKGROUND

The diagnosis of pulmonary tularaemia can be challenging. We present a case illustrating how pulmonary tularaemia may be an important radiological differential diagnosis to lung cancer.

CASE PRESENTATION

A man in his fifties presented with several weeks of dry cough, weight loss and profuse night sweats. The physical examination was normal. A chest computer tomography showed evidence of lymphadenopathy and two consolidated lung masses. The lung masses and lymph nodes showed signs of necrosis. The radiological findings were described as suspicious of lung cancer. A detailed history revealed that he had chopped wood prior to symptom onset. He tested positive for Francisella tularensis IgM and IgG, confirming the diagnosis of pulmonary tularaemia.

INTERPRETATION

The radiological findings in pulmonary tularaemia may mimic lung cancer. Serology is an easy way to confirm the diagnosis, if faced with clinical or radiological suspicion of pulmonary tularaemia.

Topics: Antibodies, Bacterial; Cough; Diagnosis, Differential; Francisella tularensis; Humans; Lung Neoplasms; Male; Tularemia

PubMed: 34423953
DOI: 10.4045/tidsskr.21.0245

Review

Authors: Briana Zellner, Jason F Huntley

, the causative agent of the zoonotic disease tularemia, is characterized by high morbidity and mortality rates in over 190 different mammalian species, including humans. Based on its low infectious dose, multiple routes of infection, and ability to induce rapid and lethal disease, has been recognized as a severe public health threat-being designated as a NIH Category A Priority Pathogen and a CDC Tier 1 Select Agent. Despite concerns over its use as a bioweapon, most U.S. tularemia cases are tick-mediated and ticks are believed to be the major environmental reservoir for in the U.S. The American dog tick () has been reported to be the primary tick vector for , but the lone star tick () and other tick species also have been shown to harbor . This review highlights what is known, not known, and is debated, about the roles of different tick species as environmental reservoirs and transmission vectors for a variety of genotypes/strains.

Topics: Animals; Dermacentor; Disease Reservoirs; Dog Diseases; Dogs; Francisella tularensis; Genotype; Host-Pathogen Interactions; Humans; Ixodidae; Symbiosis; Tick-Borne Diseases; Ticks; Tularemia; United States

PubMed: 31139576
DOI: 10.3389/fcimb.2019.00146

Review

Authors: Jeannine M Petersen, Martin E Schriefer

Francisella tularensis is a gram-negative coccobacillus and the etiologic agent of the zoonotic disease tularemia. First described in 1911 in Tulare County, California, it has since been reported throughout the Northern Hemisphere, with natural infections reported among an unusually wide range of vertebrates and invertebrates. In recent years, tularemia has emerged in new geographic locations, populations, and settings. This review will serve to highlight mechanisms contributing to the recent emergence of tularemia as well as a repertoire of diagnostic tools useful for detecting and diagnosing disease.

Topics: Animals; Communicable Diseases, Emerging; Disease Outbreaks; Francisella tularensis; Global Health; Humans; Tularemia

PubMed: 15845234
DOI: 10.1051/vetres:2005006

Authors:

In June 2000, seven cases of tularemia were reported to the Oklahoma State Department of Health (OSDH) over an 18-day period. Enhanced tularemia surveillance by OSDH during July-September 2000 detected four additional cases. During 1995-1999, an average of six cases were reported each year. This report summarizes clinical and epidemiologic information from the investigation of the 11 cases, presents three case reports to illustrate different risk factors for tularemia, and underscores the danger of delayed diagnosis of tularemia and the risk for acquiring tularemia in laboratory settings. Physicians should consider tularemia in ill persons with fever who reside in or visit areas where the disease is endemic and who have been exposed to ticks or carcasses or tissue from rabbits or other animals.

Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Fatal Outcome; Female; Humans; Male; Middle Aged; Oklahoma; Risk Factors; Tularemia

PubMed: 11787577
DOI: No ID Found

Authors: R Hornick

Topics: Animals; Disease Outbreaks; Disease Reservoirs; Francisella tularensis; Humans; Massachusetts; Pneumonia, Bacterial; Rabbits; Risk Factors; Tularemia

PubMed: 11757513
DOI: 10.1056/NEJM200111293452211

Review

Authors: Betul Copur, Serkan Surme

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.

Topics: Humans; Francisella tularensis; Tularemia; Water

PubMed: 36334909
DOI: 10.1016/j.tmaid.2022.102489

Review

Authors: A Tärnvik, L Berglund

Tularaemia is a zoonotic bacterial disease of the Northern hemisphere. The causative agent, Francisella tularensis, is spread to humans by direct contact with infected rodents or lagomorphs, aerogenic exposure, ingestion of contaminated food or water, or by arthropod bites. The prevalence of tularaemia shows a wide geographic variation. In some endemic regions, outbreaks occur frequently, whereas nearby rural parts of a country may be completely free. F. tularensis is a facultative intracellular pathogen and its primary mammalian target cell is the mononuclear phagocyte. When tularaemia is acquired via the skin, a primary ulcer is often detected and in general, regional lymph nodes become prominently enlarged. When contracted by inhalation, the disease may present with pneumonia. Nearly as frequent, however, is the development of fever and general illness with no respiratory symptoms and no pulmonary radiological changes. When present, the changes vary widely and may sometimes include hilar enlargement indistinguishable from that of lymphoma. Within an outbreak, the first case of tularaemia is not always readily diagnosed. A decade may have lapsed since the disease was encountered and its existence may be more or less forgotten. The difficulty refers especially to the respiratory form, in which symptoms are less specific. In cases of atypical pneumonia or acute febrile disease with no local symptoms, a history of exposure to hares or rodents or merely living in an endemic region should be sufficient to include tularaemia among differential diagnoses. The microbiological diagnosis of tularaemia relies mainly on serology, and the treatment on broad-spectrum antibiotics. For decades, a live vaccine has been successfully used in risk groups but is presently not available due to difficulties in standardisation.

Topics: Bacterial Vaccines; Francisella tularensis; Humans; Prevalence; Tularemia

PubMed: 12608453
DOI: 10.1183/09031936.03.00088903