Transcript CATEGORY A

CHLAMYDIA, RICKETTSIA
AND MYCOPLASMA
Biological Agents/Diseases APPROVED CDC LIST (2003)
(FEDERAL BIODEFENSE & BIOTERRORISM)
CATEGORY A
» Anthrax (Bacillus anthracis)
» Botulism (Clostridium botulinum toxin)
» Plague (Yersinia pestis)
» Smallpox (variola major)
» Tularemia (Francisella tularensis)
» Viral hemorrhagic fevers (filoviruses [e.g., Ebola, Marburg] and arenaviruses [e.g., Lassa, Machupo])
CATEGORY B
» Brucellosis (Brucella species)
» Epsilon toxin of Clostridium perfringens
» Food safety threats (e.g., Salmonella species, Escherichia coli O157:H7, Shigella)
» Glanders (Burkholderia mallei)
» Melioidosis (Burkholderia pseudomallei)
» Psittacosis (Chlamydia psittaci)
» Q fever (Coxiella burnetii)
» Ricin toxin from Ricinus communis (castor beans)
» Staphylococcal enterotoxin B
» Typhus fever (Rickettsia prowazekii)
» Viral encephalitis (alphaviruses [e.g., Venezuelan equine encephalitis, eastern equine encephalitis, western
equine encephalitis])
» Water safety threats (e.g., Vibrio cholerae, Cryptosporidium parvum
CATEGORY C
» Emerging infectious diseases such as Nipah virus and hantavirus
I. CHLAMYDIA IS THE PROTOTYPE
OBLIGATE INTRACELLULAR PATHOGEN
FOUR SPECIES:
NATURAL HOSTS:
1. C. trachomatis:
humans, mice and pigs
2. C. pneumoniae :
humans and horses
3. C. psittaci:
birds, mammals and humans
4. C. pecorum:
cattle and sheep
CHLAMYDIA LIFE CYCLE
ELEMENTARY BODY OF CHLAMYDIA
ELECTRON MICROSCOPY OF CHLAMYDIA LIFE CYCLE
Properties of Chlamydial Particles
Property
Elementary body
Reticulate body
0.2 – 0.4 μm
0.6 – 1.0 μm
Rigid cell wall
Yes
No
Extracellular stability
Yes
No
Infective
Yes
No
Induces phagocytosis
Yes
No
Inhibits phagosome
fusion with lysosome
Yes
No
Toxic
Yes
No
Metabolic activity
No
Yes
Replication
No
Yes
Size
II. MEDICALLY IMPORTANT SPECIES
III. CHLAMYDIA TRACHOMATIS
There are at least 19 serovars (A-L)
Different serovars are associated with distinct clinical signs
Endemic trachoma is associated with serovars:
A, B, Ba, and C
Sexually transmitted disease (STD) is associated with serovars:
D, Da, E, F, G, Ga, H, I, Ia, J, & K (D-K)
Lymphogranuloma venereum (STD) is associated with serovars:
L1, L2, L2a, and L3 (L1-L3)
CHLAMYDIA TRACHOMATIS
INCLUSION BODIES
CHLAMYDIA TRACHOMATOUS
Trachoma: Later stage of the formation of trachomatous pannus
Women
Increased susceptibility
PID
to HIV
Cervical Infection
(Usually assymptomatic)
Fallopian tube
Ectopic pregnancy
Infertility
Infection of infant
Self-limiting
Pneumonia
eye infection
(Conjunctivitis)
Men
Painful urination
(discharge)
Urethral infection
(Non-gonorrheal urethritis)
May be assymptomatic
Reactive arthritis
May cause Reiter’s syndrome
(Usually in men)
REITER’S SYNDROME
Genital lesions, Conjunctivitis, papules on soles of feet, Arthritis
CHLAMYDIA TRACHOMATIS SEROVARS L1, L2, & L3
LYMPHOGRANULOMA VENEREUM: Enlarged and ulcerative inguinal lymph node
IV. CHLAMYDOPHILA PSITTACI
 Primarily a pathogen of birds, elementary bodies are excreted in
droppings.
 Humans inhale elementary bodies, causing a flu-like illness
(“parrot fever”- ornithosis)
 After an incubation period of 5 to 14 days the human develops
headache, high fever, chills, malaise, myalgia, pulmonary consolidation,
and nonproductive cough.
 Often dissemination to CNS. May cause encephalitis.
 Occasionally leads to death.
 Diagnosis is usually made by serology.
 Treatment with either Tetracyclines or erythromycin
V. CHLAMYDOPHILA PNEUMONIAE
 Human to human transmission (No animal reservoir)
 Causes bronchitis, pneumonia and sinusitis.
 Infection in humans very common with several hundred thousand
cases each year in the US.
 Causes a mild to severe “atypical pneumonia” similar to those
caused by Mycoplasma pneumoniae and Legionella.
 Diagnosis by serology and by specific PCR.
 Tetracyclines and erythromycin are drugs of choice.
 A lot of published data suggest an etiologic association
with atherosclerosis and coronary artery disease
 (Still in question). The organisms are ubiquitous.
VI. RICKETTSIAE
AND RICKETSIA-LIKE ORGANISMS
ALL of these organisms are:
1. Small Gram negative coccobacilli
2. Obligate intracellular pathogens
3. Arthropod borne
4. With the exception of one group all
have a non-human host and are zoonotic
5. They are all susceptible to Tetracyclines
VII. RICKETTSIA & ORIENTIA
Typhus and Spotted fevers
These organisms are divided into distinct groups:
1. The spotted fever group with many species
The most important species is Rickettsia rickettsii
The etiology of ROCKY MOUNTAIN SPOTTED FEVER
2. The typhus Group:
Rickettsia prowazekii causes epidemic typhus
Rickettsia typhi causes murine typhus
3. The scrub typhus group:
Orientia tsutsugamushi causes scrub typhus
VIII. COXIELLA
BURNETII: Q-FEVER
IX. EHRLICHIA
An Emerging Pathogen (Many Species)
These are small Gram Negative rods
(Rickettsia-like)
They are obligate intracellular pathogens of either monocytes
or PMNs but NOT erythrocytes
(3 groups) All but one species are arthropod borne.
E. sennetsu (restricted to Japan) causes disease in humans
from eating raw fish
Most species are transmitted from mammals to humans
by ticks: Zoonoses).
At least 3 forms of human disease (All are febrile illnesses):
Sennetsu
Human Monocytic Ehrlichiosis
Human Granulocytic Ehrlichiosis
Diagnosis can be difficult, best made using either serology or
species specific DNA probes.
X. MYCOPLASMA UREAPLASMA & L-Forms
XI. MYCOPLASMA PNEUMONIAE