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CHLAMYDIA, RICKETTSIAAND 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. I. CHLAMYDIACHLAMYDIA IS THE PROTOTYPE IS THE PROTOTYPE OBLIGATE INTRACELLULAR PATHOGENOBLIGATE INTRACELLULAR PATHOGEN
FOUR SPECIES: NATURAL HOSTS: 1. C. trachomatis: humans, mice and pigs2. C. pneumoniae : humans and horses 3. C. psittaci: birds, mammals and humans4. C. pecorum: cattle and sheep
CHLAMYDIACHLAMYDIA LIFE CYCLE LIFE CYCLE
ELEMENTARY BODY OF ELEMENTARY BODY OF CHLAMYDIACHLAMYDIA
ELECTRON MICROSCOPY OF ELECTRON MICROSCOPY OF CHLAMYDIACHLAMYDIA LIFE CYCLE LIFE CYCLE
Property Elementary body Reticulate body
Size 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
Properties of Chlamydial ParticlesProperties of Chlamydial Particles
II. MEDICALLY IMPORTANT SPECIES
III. III. CHLAMYDIA TRACHOMATISCHLAMYDIA TRACHOMATIS
There are at least 19 serovars (A-L)There are at least 19 serovars (A-L)
Different serovars are associated with distinct clinical signsDifferent 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)
INCLUSION BODIES
CHLAMYDIA TRACHOMATISCHLAMYDIA TRACHOMATIS
Trachoma: Later stage of the formation of trachomatous pannus
CHLAMYDIA TRACHOMATOUSCHLAMYDIA TRACHOMATOUS
WomenIncreased susceptibilityto HIV
Cervical Infection(Usually assymptomatic)
Infection of infant
PneumoniaSelf-limitingeye infection(Conjunctivitis)
Fallopian tube
PID
Ectopic pregnancy
Infertility
Urethral infection(Non-gonorrheal urethritis)May be assymptomatic
MenPainful urination(discharge)
Reactive arthritis
May cause Reiter’s syndrome(Usually in men)
REITER’S SYNDROMEREITER’S SYNDROME
Genital lesions, Conjunctivitis, papules on soles of feet, Arthritis
LYMPHOGRANULOMA VENEREUM: Enlarged and ulcerative inguinal lymph node
CHLAMYDIA TRACHOMATISCHLAMYDIA TRACHOMATIS SEROVARS L1, L2, & L3 SEROVARS L1, L2, & L3
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 & ORIENTIATyphus 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. EHRLICHIAAn 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 fishMost 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 EhrlichiosisDiagnosis can be difficult, best made using either serology or species specific DNA probes.
X. MYCOPLASMA UREAPLASMA & L-Forms
XI. MYCOPLASMA PNEUMONIAE