Exam 4: Coxiella and Chlamydia Flashcards
What is Q fever caused by?
Coxiella burnetti
Describe Coxiella burnetti
Gram-negative bacteria that is highly resistant to environmental stresses such as high temperature, osmotic pressure, and ultraviolet light
What kind of pathogen is Coxiella burnetti?
Obligate intracellular bacterial pathogen
What is Q fever?
A zoonotic bacterial infection associated primarily with parturient ruminants and domestic animals such as cats
What are the most common domestic animals to get Q fever?
Sheep
Goats
Cattle
Why is Q fever in animals significant?
It serves as a source of infection for humans
Are dogs and cats the source of human infections of Q fever?
Though many dogs and cats sustain subclinical infections as evidenced by serological studies, but it is not yet known if they are sources
What does Q fever result from?
Inhalation of a spore-like small-cell variant and contact with milk, urine, feces, vaginal mucus, or semen of infected animals
Is Q fever tick-borne?
Rarely
Where does Coxiella burnetti reside and reproduce?
In the acidified phagolysosomes of host monocytes and macrophages
What is the large cell variant of Coxiella burnetti?
A vegetative form found in infected cells
What is the small cell variant of Coxiella burnetti?
The extracellular infectious form shed in milk, urine, and feces
Resistant to heat, drying, and many common disinfectants
Remains viable for weeks to years in the environment
What happens to Coxiella burnetti in Q fever?
It becomes localized in the mammary glands and placenta of infected ruminants and is excreted
What is Coxiella burnetti like in the environment?
It is very stable and has “spore-like” characteristics and may persist in the environment for several weeks
What does Coxiella burnetti persist in?
Contaminated soil
How is Coxiella burnetti transported long distance?
On dust particles and some windborne outbreaks
How is Coxiella burnetti passed?
In milk and people who consume non-pasteurized milk
What is Coxiella burnetti a major reason for?
Pasteurization of milk
What can Q fever cause?
Abortion
Stillbirth
Endometritis
What is the most characteristic sign of Q fever in ruminants?
Placentitis
What is seen with Q fever in goats and cattle?
Fetal pneumonia
How can Coxiella burnetti be identified?
With Ziehl-Neelsen or Gimenez strain
Polymerase chain reaction
What are the serologic tests available for Q fever?
Indirect immunofluorescence
ELISA
Complement fixation
How can Coxiella burnetti be isolated?
In cell cultures, ebryonated chicken eggs, or laboratory animals including mice, hamsters, and guinea pigs, but isolation is dangerous and rarely used for diagnosis
How can animals be protected from Coxiella burnetti?
Long acting injectable tetracyclines
Describe Chlamydia
Have lipopolysaccharide but either no or a very small amount of peptidoglycan
It is not susceptible to peptidoglycan inhibiting drugs such as penicilin
Is Chlamydia transmitted by arthropods?
No
What does Chlamydia generally parasitize?
Epithelial cells
What is the spore-like elementary body of Chlamydia like?
Metabolically inactive, infectious, and adapted for extracellular survival waiting to be phagocytized and infect a new host cell
What is the reticulate body of Chlamydia like?
Metabolically active, not infectious, and adapted for intracellular growth
Describe C. abortus
Causes abortion in sheep
Describe C. felis
causes chronic conjuntivitis (Chlamydial conjunctivitis), rhinitis, and bronchopneumonia in cats
Describe C. pneumoniae
Respiratory pathogen in people
Describe C. psittaci
Causes avian chlamydiosis, formerly called psittacosis in birds or poultry/fowl
What species gets infect with C. suis?
Swine
Describe C. pecorum
Causes sporadic bovine encephalomyelitis, which results in polyserositis
What is C. trachomatis found in?
People
What is one of the main transmission route of Chlamydia? So, what is often involved?
Aerosol transmission
Respiratory system
What is avian chlamydiosis accompanied by?
Conjunctivitis serositis
What do dogs infected with C. psittaci present with?
Bronchopneumonia with fever, dry cough, and keratoconjunctivitis
In cats infected with C. felis, what results?
Conjunctivitis and/or bronchopneumonia
Why is chlamydia difficult to treat?
Minimal symptomology
Latency of infection
Susceptibility of compromised host to reinfection
What are generally the drugs of choice for Chlamydia?
Tetracylcines or fluoroquinolones
Does the concept of prophylactic immunization that elicits sterilizing immunity and 100% protection apply to chlamydiae?
No
What is available to prevent abortions in small ruminants?
C. abortus live vaccines
What does Chlamydia psittaci causes?
Avian chlamydiosis (parrots)
Human psittacosis
Seminal vesiculitis (sheep and cattle)
Pneumonia (kittens, lambs, pigs, and foals)
Conjunctivitis (lambs, calves, piglets, and cats)
Synovial tissue arthritis (lambs, calves, piglets, and foals)
How is C. psittaci transmitted?
Fecal-oral route or by inhalation
What do respiratory discharge or feces from birds infected with C. psittaci contain?
Elementary bodies that are resistant to drying and can remain infective for several months when protected by organic debris
What happens after inhalation or ingestion of C. psittaci?
Elementary bodies attach to mucosal epithelial cells
What happens to elementary bodies once they are in endosomes?
They differentiate into metabolically active noninfectious reticulate bodies that divide and multiply by binary fission forming numerous infectious, metabolically inactive elementary bodies
What does confirmation of avian chlamydiosis require?
Isolation and identification of C. psittaci in chick embryo or cell cultures (BGM, L929, Vero) at a qualified laboratory
Describe the treatment of avian chlamydiosis
Human and avian chlamydiosis is a reportable disease
No effective vaccine for use in birds is available
Tetracyclines are the antibiotics of choice
What is the agent of feline chlamydiosis?
Chlamydophila felis
What is the main symptom of feline chlamydiosis?
Conjunctivitis
What is feline chlamydiosis also know as?
Feline pneumonitis
Why is feline pneumonitis misleading?
These bacteria rarely cause pneumonia in cats
If feline chlamydiosis is left untreated, what will happen?
Infection will clear spontaneously, but conjunctivitis may recur every 10-14 days
What has been recognized as one of the most important causes of abortion in sheep?
Chlamydial abortion
What is the difference between the frequency of abortion in cattle and pigs versus sheep and goats with Chlamydia abortus?
In cattle and pigs, abortion is much more sporadic and less common than the disease in sheep and goats
How long should aborting ewes be kept separate?
Until their uterine discharges dry up
How can you control Chlamydia abortus?
By isolating all affected ewes and lambs and treating in-contact ewes with long-acting oxytetracycline or oral tetracycline
Is vaccination recommended for Chlamydia abortus?
No
What is epitheliocystis?
Disease of the gills in fish which is considered to be Chlamydia or a Chalmydia-like organism
