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Questions and Answers
A researcher is investigating the pathogenesis of Francisella tularensis. Which cell type is MOST likely to be the primary target of infection in vivo, facilitating systemic spread?
A researcher is investigating the pathogenesis of Francisella tularensis. Which cell type is MOST likely to be the primary target of infection in vivo, facilitating systemic spread?
- Neutrophils, due to their early recruitment to sites of inflammation.
- Reticuloendothelial cells, such as macrophages and dendritic cells, leading to dissemination through the lymphatic system. (correct)
- Epithelial cells lining the respiratory tract, allowing for rapid airborne transmission.
- Erythrocytes to facilitate hematogenous spread and evade immune detection.
Francisella tularensis is NOT commonly cultured in routine clinical laboratories due to:
Francisella tularensis is NOT commonly cultured in routine clinical laboratories due to:
- The high risk of laboratory-acquired infections and need for specialized media. (correct)
- The lack of specific, cost-effective antibiotics for decontamination.
- Its rapid growth rate, which overwhelms standard culture media.
- Its strict anaerobic requirements, which are difficult to maintain in standard incubators.
A hunter develops flu-like symptoms, including fever and chills, after skinning a rabbit. A lesion is observed on their hand, and regional lymph nodes are enlarged. What is the MOST likely form of tularemia presenting in this case?
A hunter develops flu-like symptoms, including fever and chills, after skinning a rabbit. A lesion is observed on their hand, and regional lymph nodes are enlarged. What is the MOST likely form of tularemia presenting in this case?
- Ulceroglandular tularemia, resulting from direct contact with infected animal tissue. (correct)
- Typhoidal tularemia, from ingesting improperly cooked rabbit meat.
- Oculoglandular tularemia, caused by accidental inoculation of the conjunctiva.
- Pneumonic tularemia, due to the inhalation of aerosolized bacteria during the skinning process.
Why is Francisella tularensis considered a potential biological weapon?
Why is Francisella tularensis considered a potential biological weapon?
Which of the following diagnostic methods poses the GREATEST risk to laboratory personnel when attempting to identify Francisella tularensis?
Which of the following diagnostic methods poses the GREATEST risk to laboratory personnel when attempting to identify Francisella tularensis?
Following a tick bite, a patient presents with regional lymphadenopathy but no ulceration at the bite site. Which specific type of tularemia is MOST likely?
Following a tick bite, a patient presents with regional lymphadenopathy but no ulceration at the bite site. Which specific type of tularemia is MOST likely?
A microbiologist is tasked with differentiating between Francisella tularensis Type A and Type B. Which characteristic is MOST useful for this distinction?
A microbiologist is tasked with differentiating between Francisella tularensis Type A and Type B. Which characteristic is MOST useful for this distinction?
A farmer in Arkansas presents with nausea, vomiting, diarrhea, and abdominal pain after consuming undercooked rabbit meat. Which form of tularemia is MOST consistent with these symptoms and exposure route?
A farmer in Arkansas presents with nausea, vomiting, diarrhea, and abdominal pain after consuming undercooked rabbit meat. Which form of tularemia is MOST consistent with these symptoms and exposure route?
A patient is diagnosed with pneumonic tularemia. What are the MOST likely routes of infection that could have led to this presentation?
A patient is diagnosed with pneumonic tularemia. What are the MOST likely routes of infection that could have led to this presentation?
Which of the following vectors is LEAST associated with the transmission of Francisella tularensis to humans?
Which of the following vectors is LEAST associated with the transmission of Francisella tularensis to humans?
Flashcards
Francisella tularensis
Francisella tularensis
Zoonotic pathogen causing rabbit and deerfly fever.
Type A F. tularensis
Type A F. tularensis
More virulent type of Francisella tularensis found in the U.S.
F. tularensis characteristics
F. tularensis characteristics
Gram-negative coccobacilli that requires cysteine for growth and is highly infectious.
F. tularensis transmission
F. tularensis transmission
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Common Tularemia Symptoms
Common Tularemia Symptoms
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Ulceroglandular tularemia
Ulceroglandular tularemia
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Oculoglandular tularemia
Oculoglandular tularemia
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Pneumonic tularemia
Pneumonic tularemia
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Tularemia Diagnosis
Tularemia Diagnosis
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Tularemia Treatment
Tularemia Treatment
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Study Notes
- Francisella tularensis is a zoonotic pathogen.
- It causes rabbit and deerfly fever.
- Carriers include rabbits, deer, and various rodents.
- Type A is more virulent and present in the U.S., while Type B is less virulent and found in Europe.
- It's a Gram-negative, pleomorphic coccobacilli, obligate aerobe, non-motile, and intracellular pathogen.
- It's highly infectious, needing only 10 organisms to cause disease via inhalation or inoculation.
- F. tularensis is a dangerous potential biologic weapon.
- It primarily infects reticuloendothelial cells like macrophages, dendritic cells, and hepatocytes.
- It has complex growth requirements, needing cysteine.
- Cultures require 3+ days for growth.
- Routine labs don't commonly culture F. tularensis due to its fastidious nature and biosafety risk, cultures need specialized media.
- It is enzootic in all states, with most cases in rural Arkansas and Missouri.
- Risk groups include hunters, lab personnel, and those exposed to ticks and biting arthropods.
- Vectors include ticks, mites, and lice.
- Transmission occurs through skin contact (ulceroglandular tularemia), ingestion of infected meat (GI tularemia), inhalation (pneumonia), and tick bites (tick-borne tularemia from a rabbit reservoir).
- Most infections occur during wet summers.
- Bacteria spread from local lesions to regional lymph nodes, causing enlargement, tenderness, and possible pus formation.
- It can spread via the lymphatic system to organs like skin, lungs, liver, spleen, kidneys, and the CNS.
- Symptoms vary from mild to fulminant and fatal.
- The most common symptoms are flu-like: chills, fever, headache, malaise, loss of appetite, and fatigue.
Ulceroglandular Tularemia
- It is the most common presentation.
- Develops through contact with contaminated animal products or insect bites.
- Causes lesions and lymphadenopathy.
Glandular Tularemia
- Leads to lymphadenopathy without ulceration.
Oculoglandular Tularemia
- The organism enters through the conjunctiva, causing inflammation.
Pharyngeal Tularemia
- The organism enters through the pharynx, causing a severe sore throat.
Pneumonic Tularemia
- Caused by inhalation of infectious aerosols or bacteremia spread.
- Causes pneumonia.
- Diagnosis is based on clinical presentation + exposure history.
- Lab tests aren't often done due to high contagion and cysteine-containing medium requirements.
- Agglutination tests and fluorescent-antibody stains of infected tissue can be performed.
- Treatment includes streptomycin or gentamicin + tetracycline.
Typhoidal Tularemia
- Caused by ingestion of undercooked meat.
- Causes nausea, vomiting, diarrhea, and abdominal pain.
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