Tularemia Flashcards
What is the causative agent of tularemia?
Francisella tularensis.
Name the two subspecies of Francisella tularensis.
Type A (tularensis) and Type B (palaeartica).
What are the major target organs affected by tularemia?
Lymph nodes, lungs, pleura, spleen, liver, and kidney.
How is F. tularensis primarily transmitted to humans?
By arthropod bites, direct contact with infected animals, ingestion of contaminated water or food, or inhalation of infective aerosols.
What is the mortality rate of untreated cutaneous disease caused by F. tularensis subspecies tularensis?
Mortality of 5-6%.
What are the seven forms of tularemia?
Ulceroglandular, glandular, oropharyngeal, oculoglandular, typhoidal, septic, pneumonic.
What are the different routes and modes of transmission of tularemia?
Skin, GI tract, respiratory tract, handling of infected animals, bite of infected blood-sucking deer flies and wood ticks, ingestion of improperly cooked meat or contaminated water, aerosol inhalation.
Describe the epidemiology of tularemia.
Tularemia is reported from most countries in the northern hemisphere, with varying occurrence over time and region.
Where can F. tularensis survive for weeks?
Water, soil, moist hay, straw, decaying animal carcasses.
What are the principal natural reservoirs for F. tularensis?
Small and medium-sized mammals such as rabbits, aquatic rodents, rats, squirrels, lemmings, and mice.
Name the vectors responsible for transmitting tularemia.
Ticks, mosquitoes, biting flies.
What are some alternative names for tularemia?
Deer-fly fever, glandular tick fever, market men’s disease, rabbit fever, O’Hara’s disease.
Provide examples of countries and the number of tularemia cases reported during specific time periods.
Examples include Japan (1924-1987: 1,355 cases), Slovakia (1985-1994: 126 cases), and Turkey (1988-1998: 205 cases).
Describe the gram stain characteristics of Francisella tularensis.
Poorly staining, tiny Gram-negative coccobacilli.
What are the morphological and physiological characteristics of F. tularensis?
Small, weakly staining gram-negative coccobacillus, nonmotile, obligate anaerobe, weakly catalase positive, displays bipolar staining with Giemsa stain.
How does F. tularensis appear in Gram stain?
Poorly staining, tiny Gram-negative coccobacilli.
Describe the capsule of Francisella tularensis.
It displays a thick capsule.
What are the culture characteristics of F. tularensis?
Slow growing, requires iron and cysteine or cystine, no growth on routine culture media.
What methods are used for detecting F. tularensis?
PCR, ELISA, time-resolved fluorometry (TRF) assay system, mass spectroscopy (MS).
Why are vaccines not suitable for treatment after exposure to tularemia?
Vaccines take too long to be effective.
What antibiotics are effective for treating tularemia after exposure?
Tetracyclines and chloramphenicol.
What are the pros and cons of using tetracyclines and chloramphenicol for tularemia treatment?
Pros: Effective against tularemia, can be administered orally, low toxicity. Cons: Higher relapse rate than aminoglycosides.
Why must antibiotic treatment for tularemia begin several days post-exposure?
To prevent relapse.
What is the effectiveness of PCR in detecting F. tularensis?
PCR is rapid and accurate.
Describe the advantages of time-resolved fluorometry (TRF) assay system in F. tularensis detection.
Time-resolved fluorometry (TRF) assay system is more accurate and sensitive.
How does mass spectrometry (MS) contribute to F. tularensis detection?
It allows for detection of whole bacteria and isolated coat proteins.
Why are new portable MS systems unreliable in the field for F. tularensis detection?
They are still unreliable for field use.
Why are safety measures crucial in clinical laboratories regarding F. tularensis?
To avoid laboratory-associated infections.
What are the consequences of a potential bioterrorism threat involving F. tularensis?
F. tularensis is of great concern as a potential bioterrorism agent.
How does the risk posed by tularemia relate to the preparedness of the public health system?
The risk can be managed if the public health system is well-prepared.
