COXIELLA BURNETIIBy : Milad shahini shams abadi

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OVERVIEW

HistoryCharacteristics Mechanisms in bacteriTransmissionDiagnosisTreatment

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HISTORY

First reported :The first reported was in Brisbane, Queensland, Australia, in 1935 by Derrick.

Isolated the organism :Burnet and his associate Freeman successfully isolated the organism and concurrently, a similar agent was isolated from ticks in Montana by Davis and Cox.

Named Coxiella burnetii :. In 1938 the organism was named Coxiella burnetii in honor of Cox and Burnet.

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CHARACTERISTICS

Obligate intracellular pathogen Proteobacteria Gram-negative Two antigenic phases

Phase 1: virulent Phase 2: less pathogenic

Stable and resistant

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MECHANISMSThe intracellular trafficking pathway of Coxiella burnetii.

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MECHANISMSThe type IVB secretion systems of Coxiella burnetii and Legionella pneumophila.

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MECHANISMSRoles of type IV secretion system effectors during Coxiella burnetiiintracellular infection.

Cig57

Cig2

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DISEASEThe important disease in human is Q fever : Incubation: 2 to 5 weeks One organism may cause disease Humans are dead-end hosts Disease

Asymptomatic (50%) Acute Chronic

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TRANSMISSIONAerosol

Parturient fluids 109 bacteria released per gram of placenta

Urine, feces, milkDirect contactFomites IngestionArthropods (ticks)

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TRANSMISSION Person-to-person (rare)

Transplacental (congenital) Blood transfusions Bone marrow transplants Intradermal inoculation Possibly sexually transmitted

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DIAGNOSIS Serology (rise in titer)

IFA, CF, ELISA, micro-agglutination DNA detection methods

PCR Isolation of organism

Risk to laboratory personnel Rarely done

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TREATMENT Treatment

Doxycycline Chronic disease – long course

2 to 3 years of medication Immunity

Long lasting (possibly lifelong)

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A BIOLOGICAL WEAPON Accessibility Low infectious dose Stable in the environment Aerosol transmission WHO estimate

5 kg agent released on 5 million persons 125,000 ill - 150 deaths Could travel downwind for over 20 km

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