VIRUS
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CHIKUNGUNYA
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DENGUE
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ZIKA
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Cause
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Single stranded RNA alphavirus.
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Dengue flavivirus.
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Zika flavivirus.
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Transmission
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Vector: Aedes aegypti, A. albopictus.
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Vector: Aedes aegypti, A. albopictus.
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Vector: Aedes aegypti, A. albopictus, A. africanus
Non Vector: Congenital, Perinatal, Sexual.
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History
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Endemic area, travel, contact may be present.
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Endemic areas.
Travel History.
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Endemic areas.
Travel History.
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Clinical Presentation
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Incubation period 2-5 days.
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Incubation period.
4-10 days.
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Incubation period 3–10 days.
80% cases asymptomatic.
Self-limiting.
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Fever
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High Grade >= 39 °C.
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High Grade >= 39 °C.
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Low Grade <= 38°C.
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Rash
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Macular, macular papular on limbs.
Diffuse pigmented, bullous lesions described in children.
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Macular papular, Haemorrhagic.
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Maculopapular, pruritic – starts proximally with distal spread.
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Joint Presentation
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Painful swollen joints, tenosynovitis, predilection for distal small joints.
Chronic Persistent Arthritis.
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Arthralgia, transient synovitis, Macrophage activation syndrome.
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Arthralgia.
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Other symptoms
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Headache, Conjunctivitis, Myalgia, Lymphadenopathy, Neuropathy, GIT symptoms.
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Severe headache, retro orbital pain, myalgia, lymphadenopathy, GIT symptoms.
Severe: Bleeding dyscrasia, shock.
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Conjunctivitis, myalgia, headache.
Meningitis, Guillaine Barre in adults.
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Laboratory Tests
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Full blood count (FBC) may show lymphopaenia, thrombocytopaenia.
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Marked cytopenia (all cell lines).
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FBC often normal or mild changes.
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Inflammatory markers: ESR and CRP may be normal.
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ESR/CRP may be normal.
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ESR/CRP normal or slightly raised.
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Diagnosis
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Serology IgM + > 4 days (in acute phase), IgG positive > 2 weeks of onset (be aware of cross reactivity).
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Serology IgM + > 4 days (in acute phase), IgG positive > 2 weeks of onset (be aware of cross reactivity).
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Serological testing not recommended due to cross reactivity with other flaviviruses.
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Reverse Transcriptase PCR + during acute phase (in first week of illness).
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Reverse Transcriptase PCR + during acute phase (in first week of illness).
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Reverse Transcriptase PCR on serum and urine in acute phase < 14 days from onset of symptoms.
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Synovial biopsy may demonstrate virus.
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Isolating virus: Immunofluorescence biopsy/ post mortem specimens.
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Treatment
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Supportive (i.e., fluids, analgesia, non-steroidal anti inflammatory drugs - NSAIDS).
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Supportive.
Avoid NSAIDS as may exacerbate haemorrhage.
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Supportive.
Avoid NSAID’s until Dengue excluded.
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