Rickettsia and Chlamydias: Pathogenesis, Diseases, and Detection Methods

What type of bacteria are Rickettsia?

Gram negative bacilli, nonmotile, and highly pleomorphic.

How do Rickettsia stain with Gram stain?

They stain poorly but can be better visualized with Giemsa stain.

What is a unique characteristic of Rickettsia?

They are obligate intracellular parasites with functional genes for protein synthesis, ATP production, and reproduction.

What is the significance of Rickettsia's genome size?

They have an extremely small genome and require a host cell to replicate and survive.

What are the main transmission vectors for Rickettsia?

Transmitted from animals by arthropod vectors such as ticks, lice, and mites.

Which species of Rickettsia cause most human infections?

R. rickettsii, R. prowazekii, and R. typhi.

What disease is caused by Rickettsia rickettsii?

Rocky Mountain spotted fever.

What are the symptoms of Rocky Mountain spotted fever?

Most infected individuals develop a rash on the trunk and appendages, with approximately 5% mortality.

How is Rickettsia prowazekii transmitted?

By human body lice in crowded, unsanitary conditions.

What disease does Rickettsia prowazekii cause?

Epidemic typhus.

What are the symptoms of murine typhus caused by Rickettsia typhi?

Fever, headache, chills, muscle pain, and nausea.

What biosafety level practices are required for handling Rickettsia?

Biosafety Level 3 practices during handling and testing.

What is the primary characteristic of Chlamydia bacteria?

They do not have cell walls and grow only within the vesicles of host cells.

What are the two forms of Chlamydia during its developmental cycle?

Elementary bodies (EBs) and reticulate bodies (RBs).

What is the most common sexually transmitted disease caused by Chlamydia?

Chlamydia trachomatis infections.

What disease is caused by Chlamydia trachomatis serovars L1-L3?

Lymphogranuloma venereum.

What is the leading cause of nontraumatic blindness in humans?

Trachoma caused by Chlamydia trachomatis serovars A and B.

What is the treatment for Chlamydia infections?

Antibiotics can be administered for genital and ocular infections.

What disease does Chlamydia pneumoniae cause?

Bronchitis, pneumonia, and sinusitis.

What are the symptoms of ornithosis caused by Chlamydia psittaci?

Flu-like symptoms in individuals who handle infected birds.

What is the causative agent of Q fever?

Coxiella burnetii.

How is Coxiella burnetii transmitted?

Through inhalation or contact with infected animal products.

What are common symptoms of Q fever?

High fever, severe headache, chills, diarrhea, and pneumonia.