Chlamydia Lecture Notes

Chlamydia Lecture Notes

• Learning Outcomes: Students will gain knowledge of animal structure, function, immunology, inflammation, and the biology of animal pathogens (bacteria, parasites, and viruses).
• Learning Objectives: Students will be able to:
  • Name Chlamydia species associated with animal and human disease.
  • Describe the chlamydial developmental cycle.
  • Identify common features of chlamydial infections.
  • Provide examples of diseases caused by Chlamydiae in different hosts.
  • Explain protective and sterile immunity related to strategies to prevent and control chlamydial infections.
• Chlamydia species: There are almost twenty species in the genus Chlamydia, with nine significantly associated with animal or human disease. At least five others and four candidate species are found in animals' eyes, reproductive and gastrointestinal tracts with minimal or no apparent pathology.
• Classification Changes: The original genus Chlamydia was subdivided into two (Chlamydia and Chlamydophila) in 1999, but has since been reconsidered as a single genus.
• Specific Chlamydia species and associated diseases:
  • C. trachomatis: Human ocular/urogenital infection, blindness, infertility.
  • C. pneumoniae: Human, horse, koala, respiratory/multisystem disease.
  • C. pecorum: Ruminants, pigs, koalas, enteric/multisystem disease.
  • C. caviae: Guinea pigs, conjunctivitis, pneumonitis.
  • C. psittaci: Birds, human, respiratory disease.
  • C. abortus: Sheep, goats, human, abortion.
  • C. felis: Cats, conjunctivitis/rhinitis.
  • C. muridarum: Mice, respiratory and urogenital disease.
  • C. suis: Pigs, pneumonia, enteritis, conjunctivitis.
  • Other species listed include C. avium, C. gallinacean, C. serpentis, C. poikilothermis, C. buteonis, C. crocodili, and examples of Candidatus species like C. corallus, C. sanzinia, C. ibidis, C. testudines.
• Chlamydial Infections: Diseases can be persistent or chronic, re-infections are common, and often involve immunopathology. Treatable with antibiotics. No human vaccines, but veterinary ones have been licensed for cats and sheep.

Chlamydial Developmental Cycle

• Elementary Bodies (EB): Adhere to cell membranes, enter via endocytosis, prevent phagosome-lysosome fusion. Transform to Reticulate Bodies (RB)
• Reticulate Bodies (RB): Intracellular, replicative, divide by binary fission, form inclusions (visible microscopically).
• Maturation: RBs differentiate back into EB, released by extrusion or lysis, typically infectious stage. EB cycle repeats.

Features of Chlamydial Infections

• Persistence: Can be persistent or chronic.
• Reinfection: Common.
• Immunopathology: Often involved in disease.
• Treatment: Treatable with antibiotics.
• Vaccine Absence/Presence: No human vaccines, but veterinary ones for cats and sheep.

This quiz covers the essential learning outcomes regarding Chlamydia, including its species, developmental cycle, and associated diseases in animals and humans. Students will also explore concepts like immune responses and strategies for controlling infections. Dive into the intricate world of this pathogen and enhance your understanding of immunology.