Chlamydia and Chlamydophila

chlamydiosis

Both Chlamydia spp. and Chlamydophila spp. cause the disease __________.

yes! and carriers shed C. psittaci intermittently, particularly when stressed.

Can birds be asymptomatic carriers of C. psittaci?

birds causes psittacosis (avian chlamydiosis, ornithosis, parrot fever)

*chlamydophila psittaci* species? what does it cause?

Chlamydias can't be detected by standard culturing methods. In fact, before 1983, only 200 laboratories in the US could culture them. Newly developed diagnostic tests such as enzyme immunoassays and monoclonal antibody tests have helped. They've actually revealed a previously unsuspected epidemic of chlamydial infections. Chlamydial infections are now known to be one of the most prevalent diseases in american society.

*no news may not be good news* if you've got a chlamydial infection, be prepared to hear your doctor tell you that laboratory tests proved negative for bacteria. why???

1. attachment, entry, and differentiation 2. growth by binary fission 3. differentiation 4. lysis (and re-infection)

1-4?

1. very small size (0.4 um) 2. no peptidoglycan in cell wall 3. difficult to stain with gram stain 4. obligate intracellular pathogens 5. lact ATP synthesis 6. can't be cultured easily in the lab 7. life cycle (2 forms)

7 most important facts about chlamydiae:

C. abortus in sheep

A live vaccine has been reported to decrease the shedding of _____________ and may be useful for eradication programs.

C. felis is shed in ocular and nasal secretions. It is possible for a cat to appear outwardly healthy but be shedding the bacteria which can be passed onto other cats via eye discharge. It has also been recovered from various internal organs. Persistent infection of the oviduct has been reported, suggesting that venereal transmission may be possible.

How is C. felis transmitted?

difficult to diagnose!! 1. chlamydia can be *isolated* in embryonated eggs, laboratory animals, or cell cultures. 2. *immunofluorescent* 3. *ELISA* 2 samples (fourfold or greater change in serologic titer) 4. *PCR* = mainly used for research but now introduced into labs 5. *special staining* of infected tissues (Machiavello, Giemsa, Brucella differential and modified Ziehl-Neelsen stains)

How is chlamydia *diagnosed*? (5)

*Usually treated with tetracyclines* Other antibiotics including *erythromycin and other macrolides, tylosin, quinolones and chloramphenicol* may also be used. There is a *vaccination available for C. felis*. It can reduce the severity of symptoms but doesn't prevent infection in the first place.

How is chlamydiosis *treated*?

C. psittaci (*most human chlamydiosis*) C. abortus C. felis

Not all Chlamydia and Chlamydophila strains are zoonotic. Which are?

5. None of the above **chlamydia can't be cultured easily in the lab**

Samples from Chlamydia infection cases can be diagnosed by: 1. Culture on Blood agar and Gram staining 2. Culture on enriched media and oxidase test 3. Culture on Triple Sugar Iron and coagulase test 4. All the above 5. None of the above

true

T/F chlamydiaceae have metabolic and structural differences from most bacteria

false! they can be asymptomatic carriers and shed C. psittaci for weeks to months, especially when stressed

T/F: . Birds can't be asymptomatic carriers for Chlamydophila psittaci.

false they are intracellular, but they *DO* have a cell wall

T/F: Chlamydia and Chlamydophila are obligate intracellular bacteria that lack cell wall.

false elementary bodies are metabolically inert, but they ARE *infective*

T/F: The elementary bodies of Chlamydia are metabolically active

true!! Chlamydia and Chlamydophila spp. are susceptible to most disinfectants and detergents, including a 1:1,000 dilution of quaternary ammonium compounds, 1% sodium hypochlorite, 70% ethanol, glutaraldehyde and formaldehyde.

T/F: chlamydia is susceptible to most disinfectants

no!!!!!!!!!!!!! *ELEMENTARY BODIES ARE THE ONLY INFECTIOUS STAGE OF THE LIFE CYCLE*

T/F: reticulate bodies are infectious

lipopolysaccharide peptidoglycan

The chlamydiae cell wall contains an outer ______________ membrane but lacks _____________

FYI

Until recently, the Chlamydiaceae contained only a few species: Chlamydia psittaci Chlamydia trachomatis Chlamydia pneumoniae Chlamydia pecorum However, this family has been reorganized, based on analyses of ribosomal RNA. A new genus, *Chlamydophila*, was established, some species were renamed, and some strains of C. psittaci and C. trachomatis were assigned to new species.

Psittacosis in human can be acute or insidious in onset. The disease varies from a mild, flu-like infection with a fever, chills, headaches, anorexia, malaise, sore throat and photophobia to a serious atypical pneumonia with dyspnea. Several cases of abortion and severe chlamydiosis in pregnant women associated with C. abortus have been reported.

What are symptoms of zoonotic chlamydiosis in humans?

Treatment with tetracyclines can prevent abortions in ruminants, but organisms may still be shed at birth

What can prevent abortions in ruminants?

C. psittaci

__________ is responsible for most cases of zoonotic chlamydiosis in humans

*obligate intracellular bacteria* (MUST live within host cells to survive and multiply)

chlamydia and chlamydophila are members of the family chlamydiaceae, an unusual group of ________________

type III secretion system

chlamydia encodes a _____________ through which it secretes effectors (?) into the host cell

primative

chlamydias are probably the most _________ of all bacteria

1. metabolically inert, *infective elementary body* 2. metabolically active *reticulate body*

chlamydias cycle through two forms:

Animals should be bought from sources *known to be free of this disease.* Sick cats, aborting ruminants and other animals with chlamydiosis should be *isolated.* The premises should be *cleaned and disinfected* after an abortion, and any aborted fetuses, dead lambs, contaminated bedding or placentas should be removed.

how do you *prevent* chlamydiosis?

transmitted frequently by inhalation of infectious dust and occasionally by ingestion.

how is C. psittaci transmitted?

Avian chlamydiosis occurs in most birds, but is particularly common in *psittacine birds, pigeons, doves, and mynah birds.* Sometimes seen in ducks and turkeys but only rarely in chickens.

in what species of birds does C. psittaci occur?

cysteine-rich proteins

instead of peptidoglycan, the chlamydiae cell wall contains __________ that are likely the functional equivalent of peptidoglycan

interferon, starvation, heat shock, antibiotics

mediators of persistence?

- anorexia - weight loss - diarrhea - yellowish droppings - sinusitis - respiratory distress - nervous signs - conjunctivitis decreased egg production *Nervous signs* may be seen, including transient ataxia in pigeons and trembling or gait abnormalities in ducks.

what are clinical signs of C. psittaci birds?

pneumonia airsacculitis hepatitis myocarditis epicarditis nephritis peritonitis splenitis

what are post-mortem lesions of C. psittaci

The elementary body is *smaller, metabolically inert* and relatively *stable in the environment.* Elementary bodies are *taken up by host cells* via endocytosis, but remain inside a *membrane-bound inclusion body* in the cytoplasm. After several hours, the elementary bodies *lose their thick walls* and *enlarge* to become *reticulate bodies.*

what are the characteristics of *elementary bodies* and what is their *pathway* to becoming reticulate bodies?

The reticulate body is *metabolically active* and divides several times within the inclusion body. Its *progeny* eventually differentiate into infectious *elementary bodies*, which are released when the cell *disintegrates* or the *inclusion body fuses* with the cell membrane. The reticulate bodies are not infectious

what are the characteristics of *reticulate bodies* and what is their *pathway* to becoming elementary bodies?

*Conjunctivitis* with watery discharge, as the infection progresses, the discharge becomes thicker. It may start out with discharge from one eye, but usually *spreads to both eyes*. Mild *upper respiratory symptoms* such as low grade fever, nasal discharge & sneezing may also be present

what are the clinical signs of *C. felis*?

orchitis epididymitis seminal vesiculitis decreased fertility or infertility

what can C. abortus cause in male sheep?

they depend on ATP from the host

what does it mean that family chlamydiaceae are "energy parasites"?

allows for intracellular division and extracellular survival

what does the unique chlamydiae cell wall structure allow?

Late term abortions, stillbirths and the birth of weak, low birth weight or premature offspring. A reddish-brown vaginal discharge may be seen for several days after the abortion or parturition but the dam usually remains otherwise healthy. In most ewes, there are no symptoms before the abortion, and post-abortive sickness, retained placentas and metritis are unusual.

what is enzootic abortion characterized by?

The incubation period in cage birds is usually *three days to several weeks*. However, in *latent* infections, active disease may be seen *years after infection*.

what is the *incubation period for C. psittaci*?

When the infection is maintained in the population (Enzootic is the non-human equivalent of endemic)

what is the definition of *enzootic*?

gram negative, due to their relationships with other gram negative bacteria, but are difficult to stain with the gram stain

what is the gram stain of chlamydia and chlamydophila?

Morbidity and mortality vary with the host species and pathogenicity of the serotype. *Young birds tend to be more susceptible* than older birds.

what is the morbidity and mortality rate of birds with C. psittaci? are younger or older birds more susceptible?

spherical very small size 0.4 - 0.6 um

what is the shape and size of members of chlamydiaceae?

chlamydophila felis

what species of chlamydophila affects cats?

Chlamydophila *caviae* Mainly causes *conjunctivitis* in guinea pigs. C. caviae is very host specific (experimental infections of mice, hamsters, rabbits and gerbils have failed).

what species of chlamydophila affects guinea pigs (only) and what does it cause?

(C. pneumonia) (koala strain) Has been isolated from asymptomatic koalas as well as from koalas with respiratory disease. In koalas, C. pneumoniae has been isolated from the respiratory tract, the eye and the urogenital tract.

what species of chlamydophila affects koala and what does it cause?

Chlamydia *muridarum* mostly *asymptomatic* or manifest as *pneumonia*

what species of chlamydophila affects mice and guinea pigs and what does it cause?

*chlamydophila abortus* *enzootic abortion*

what species of chlamydophila affects sheep and goats and what does it cause?

C. *suis* Found in the intestinal tract of many pigs. Most infected animals remain *asymptomatic*. It has been associated with *conjunctivitis, enteritis and pneumonia* in this species.

what species of chlamydophila affects swine and what does it cause?

Chlamydophila pecorum No specific host. Causes *encephalitis, pneumonia, enteritis, polyarthritis, conjunctivitis and abortions* in sheep, goats, cattle and pigs. It can cause *genitourinary disease* in koalas. Asymptomatic infections are also seen as most fecal isolates from *ruminants*.

what species of chlamydophila has *no specific host* and what does it cause?

*C. felis* and *C. pneumoniae* occur worldwide. *C. abortus* has been reported from most sheep-raising countries but is not found in Australia or New Zealand

where do the following occur around the world: C. felis C. pneumoniae C. abortus

it inhibits phagolysosomal fusion in phagocytes

why is the unique cell wall of chlamydiae thought to be one of its virulence factors?