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