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