week 2

• What are the learning objectives of the study material?

  • Impact and aetiology of Chlamydia sp (e.g., C. trachomatis)
  • Impact and aetiology of Rickettsia sp (e.g., Rickettsia prowazekii)
  • Understand their unique life cycle and intracellular survival

  
• What family did Chlamydia and Chlamydophila once belong to?


  They once belonged to the same family.
• What is the single genus that Chlamydia is classified under?


  Chlamydia
• Name one example of Chlamydia sp that causes ocular and genital infections.


  1. trachomatis
• What disease is caused by C. psittaci?


  Psittacosis
• What percentage of community-acquired pneumonia (CAP) is attributed to C. pneumoniae?


  10-20%
• What is the elementary body (EB) in Chlamydia?


  It is the infectious form that is metabolically inactive.
• What is the approximate size of elementary bodies (EB)?


  0.2-0.3 microns in diameter
• What are reticular bodies (RB) in Chlamydia?


  They are the intracellular reproductive form that is metabolically active.
• What is the size range of reticular bodies (RB)?


  Approximately 0.5-2 microns in diameter
• How do reticular bodies (RB) reproduce?


  They can divide by binary fission.
• What type of cells do Chlamydia inhabit?


  Epithelial cells and macrophages
• Why are Chlamydia small enough to pass through 0.45 micron filters?


  Because they are non-motile, obligate intracellular coccoid bacilli.
• What is the significance of peptidoglycan in Chlamydia?


  Its existence was debated until recent studies confirmed it.
• What is the role of Chlamydia as energy parasites?


  They lack ATP-generating ability and must obtain it from host cells.
• How many people are affected by trachoma globally?


  About 1.9 million people are blind or visually impaired due to trachoma.

  
• What does SAFE stand for in the context of trachoma prevention?


  Surgery, Antibiotics, Facial cleanliness, and Environmental improvement
• How many people received surgery for trachoma in 2018?


  146,112 people
• What percentage of global-level antibiotic coverage was achieved in 2018?


  50%
• What is the most common preventable cause of blindness?

  Chlamydia trachomatis
• What types of infections does Trachoma cause?


  Infection of conjunctival epithelial cells
• How does repeated clinical/subclinical infection of Trachoma affect the cornea?


  It can cause the cornea to cloud or scar.

  
• How is Trachoma transmitted?


  By flies, fomites, and touch.
• In what type of climate does Trachoma favor?


  Hot, dry climates
• What is the neonatal form of Inclusion conjunctivitis?


  It can develop when an infant is in the birth canal and appears 5-12 days after birth.
• What can Inclusion conjunctivitis precede in infants?


  Infant pneumonia
• What is the adult form of Inclusion conjunctivitis associated with?


  Sexual contact via STD or contaminated swimming pools.
• What is Lymphogranuloma venereum (LGV)?


  It is a severe form of genital chlamydiasis.
• What symptoms do men experience with genital chlamydiasis?


  Urethritis, mild burning, and white discharge from the penis.
• What symptoms do women experience with genital chlamydiasis?


  Urethritis, cervicitis, PID, and infertility.
• What is Psittacosis also known as?


  Parrot fever
• From how many avian species has Chlamydia psittaci been isolated?


  Over 100 avian species
• How long can the elementary bodies (EB) of Chlamydia psittaci remain resistant in feed?


  Up to 2 months
• What is the typical onset time for symptoms in patients with Psittacosis?


  Most patients develop symptoms after 10 days.
• What is the range of severity for clinical signs of Psittacosis?


  From non-apparent to severe pneumonia.
• Who are at risk for Psittacosis?


  Pigeon farmers, pet shop owners, veterinarians, and poultry workers.
• What are the four genera of Rickettsiae mentioned in the study material?

  • Rickettsia
  • Orientia
  • Coxiella
  • Erlichia
• What are the general features of Rickettsiae?


  They are obligate intracellular pathogens that multiply by binary fission in infected cells.
• What is the size of Rickettsiae?


  0.3 by 1-2 microns
• How are Rickettsiae transmitted?


  By arthropod vectors such as ticks, mites, lice, and fleas.