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What is a significant symptom of leptospirosis?
Which method is commonly used for diagnosing leptospirosis?
What is the primary vector for the transmission of Borrelia burgdorferi?
Which type of bacteria is characterized by a thick, lipid-rich, waxy cell wall?
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Which of the following symptoms is associated with liver issues in leptospirosis?
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What is the primary mechanism by which Mycobacterium tuberculosis survives within macrophages?
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Which type of immunity is primarily involved in the immune response to tuberculosis?
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What is the typical clinical manifestation of tuberculosis?
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How is tuberculosis predominantly transmitted among individuals?
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Which of the following is NOT true about Mycobacterium tuberculosis?
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What determines the outcome of exposure to tuberculosis?
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What happens to bacteria during the latency phase of tuberculosis?
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Which of the following can lead to the reactivation of latent tuberculosis?
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Which characteristic is NOT associated with caseous necrosis in tuberculosis?
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Miliary tuberculosis can disseminate to which of the following locations?
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What is a typical feature of post-primary tuberculosis?
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In healthy individuals exposed to low doses of tuberculosis, what typically occurs?
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Which organ system is most commonly affected by tuberculosis?
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What is the primary mode of transmission for Rickettsia infections?
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Which of the following conditions is caused by Chlamydia trachomatis?
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What are the two distinct stages of Chlamydia's life cycle?
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Which test is used for the serological diagnosis of Rickettsia infections?
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What severe complication can result from trachoma caused by Chlamydia trachomatis?
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What type of secretions are typically associated with genital chlamydia infections?
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What can occur in neonates due to Chlamydia trachomatis during delivery?
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Which of the following is a characteristic of the reticulate body of Chlamydia?
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What is a common initial symptom of Trachomatis infection in its first stage?
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Which Mycoplasma species is primarily associated with atypical pneumonia?
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What unique feature helps in the laboratory identification of Mycoplasma pneumoniae colonies?
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Which symptom is NOT typically associated with Mycoplasma pneumoniae infection?
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How is Mycoplasma pneumoniae primarily transmitted?
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What is a common complication that may arise from Mycoplasma pneumoniae infection?
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What characteristic distinguishes Mycoplasma from other bacteria?
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Which symptom is primarily noticed during the second stage of a Trachomatis infection?
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Study Notes
Leptospirosis
- Leptospirosis is caused by Leptospira bacteria,
- Symptoms can be flu-like or severe systemic disease,
- Severe issues include kidney, brain, liver (hepatitis and jaundice), and eye (red eye)
Diagnosing Leptospirosis
- Diagnosed through dark-field microscopy, serology, and culture,
- The bacteria is challenging to culture but is the most easily culturable spirochete,
- Blood samples are best for the first week of infection,
- Urine samples are best for the second and third weeks of infection
Borrelia
- Borrelia burgdorferi is transmitted by ticks and resides in small mammals, particularly deer,
- The bacteria causes Lyme disease characterized by bull's-eye rash, neurological conditions, cardiac issues, and arthritis
Mycobacterium
- Mycobacterium are acid-fast bacilli (AFB) due to their thick, waxy cell walls,
- Common examples include Mycobacterium tuberculosis, Mycobacterium leprae, and Mycobacterium avium-intracellulaire complex (MAC),
- The cell wall contains mycolic acids, which are unusual lipids
Mycobacterium tuberculosis
- M. tuberculosis is a facultative intracellular pathogen,
- It can survive within unactivated macrophages by using the phagocytic vacuole for survival and replication,
- The bacteria prevents fusion of the phagosome with the lysosome
Tuberculosis
- Tuberculosis is a chronic granuloma, characterized by inflammation with diverse cellular types,
- Primarily affects the lungs, but can impact various organs,
- Incidence is increasing due to the rise of AIDS cases,
- The immune response is cell-mediated immunity
Transmission of Tuberculosis
- Tuberculosis is transmitted person-to-person through the air by individuals with lung TB disease
Progression of Tuberculosis
- M. tuberculosis can survive in unactivated macrophages,
- Activated macrophages can kill the bacteria,
- The outcome of exposure depends on the individual's immune response,
- Healthy individuals with lower exposure can overcome infection with activated macrophages,
- Individuals with weaker immune responses may experience bacterial multiplication in lung macrophages and attract phagocytes to the infection site
Latency and Reactivation of Tuberculosis
- Bacteria in tubercles can remain dormant for decades,
- Immune suppression can allow bacteria to escape lesions and multiply, causing reactivation,
- Reactivation can be triggered by factors like old age, cancer, immunosuppressive drugs, and HIV infection
Progression of Pulmonary Tuberculosis
- Granuloma formation and fibrosis occur,
- Caseous necrosis develops, resulting in dry and amorphous tissue resembling cheese,
- Calcification occurs with deposition of calcium salts
Post-Primary Tuberculosis
- Primary infection might not kill all the bacteria, with some remaining dormant,
- Miliary tuberculosis can occur when the infection spreads to areas like meninges, bones, joints, and kidneys,
- Post-primary tuberculosis involves reactivation or reinfection,
- Granulomatous reactions are present but with increased tissue necrosis,
- Bacteria can access the sputum
Spread of Tuberculosis
- 85% of cases affect the lungs,
- Other areas affected include the central nervous system (brain and meninges), lymph nodes, genitourinary system, bones, and joints
Rickettsia
- Rickettsia are transmitted by arthropod vectors like ticks, fleas, and lice,
- They cause typhus fever, spotted fever, and rickettsial pox,
- Symptoms include vesicular lesions with pox-like progression
Diagnosing Rickettsia
- Serology is used for diagnosis,
- The Weil-Felix test detects antibodies that cross-react with Proteus antigens
Chlamydia
- Chlamydia are small, obligate intracellular parasites,
- They exist in two forms:
- Elementary body (EB): small, inactive, extracellular, infectious form released by the host,
- Reticulate body (RB): noninfectious, actively dividing form growing within host cell vacuoles
Chlamydia trachomatis
- Chlamydia trachomatis attacks mucous membranes of the eyes, genitourinary tract, and lungs,
- Ocular trachoma is a severe infection that deforms eyelids and corneas, potentially causing blindness,
- Inclusion conjunctivitis occurs in babies passing through infected birth canals,
- Prevented by prophylaxis
- Sexually transmitted diseases (STDs): second most prevalent STD, causing urethritis, cervicitis, Pelvic inflammatory disease (PID), and infertility,
- Lymphogranuloma venereum: disfiguring disease of the external genitalia and pelvic lymphatics
Chlamydia trachomatis in the Eye
- Causes trachoma and inclusion conjunctivitis,
- Leads to mucopurulent discharge, corneal infiltrates, vascularization, and scarring,
- In newborns, infection can occur during birth,
- Symptoms manifest 5-12 days after birth,
- Ear infections and rhinitis often accompany eye issues
Lymphogranuloma Venereum (LGV)
- Caused by C. trachomatis (LGV biovar),
- First stage: painless vesicular lesion at the infection site, fever, headache, and myalgia,
- Second stage: inflammation of draining lymph nodes, fever, headache, myalgia, buboes (rupture and drain), and ulcers
Mycoplasma
- Mycoplasma are the smallest known free-living organisms (0.15-0.3 µm),
- Two medically important species:
- M. pneumoniae: causes primary atypical pneumonia, slowly spreading across respiratory surfaces, causing fever, chest pain, and sore throat,
- M. hominis: causes genitourinary tract infections,
- They lack the typical bacterial cell wall,
- They have sterols in their cytoplasmic membrane,
- They exhibit high pleomorphism,
- They require special lipids from host membranes
Mycoplasma pneumoniae
- Infects the upper and lower respiratory tract,
- Causes primary atypical pneumonia (walking pneumonia),
- Develops slowly, with an incubation period of up to 3 weeks,
- Symptoms include fever, headache, and cough,
- Common in children and young adults,
- Transmitted through sneezing and coughing
Mycoplasma pneumoniae - Clinical Significance
- Major cause of primary atypical pneumonia,
- Transmitted through droplet infection,
- After a 2-3-week incubation, it starts as a mild upper respiratory infection, progressing to fever, headache, malaise, and dry cough,
- 3-10% develop pneumonia with complications such as arthritis, rashes, cardiovascular problems, or neurological problems
Mycoplasma pneumoniae - Laboratory Diagnosis
- Culture: using throat swabs or sputum, selective agar supplemented with serum and antibiotics, colonies exhibit a "fried egg" appearance,
- Serodiagnosis: antibody titer, cold agglutinin test, complement fixation test.
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Description
This quiz covers key information about leptospirosis, including its causes, symptoms, and diagnosis methods. Additionally, it explores other bacterial diseases such as Lyme disease caused by Borrelia and the characteristics of Mycobacterium species. Test your knowledge on these important infectious diseases!
