Chikungunya Fever
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Chikungunya Fever

Chikungunya fever is viral disease transmitted to humans by the bite of infected mosquitoes. All physicians should consider it in their differential diagnosis when they are taking care of travellers returning from the Indian Ocean and Indian sub-continent, as well as Africa. 



Mode of Transmission
It is transmitted from human to human by Aedes mosquitoes (aedes aegypti, albopictus, polynesiensis). Aedes aegypti (the yellow fever mosquito), a household container breeder and aggressive daytime biter which is attracted to humans, is the primary vector of chikungunya virus to humans. Aedes albopictus (the Asian tiger mosquito) has also played a role in human transmission in Asia, Africa, and Europe.


Epidemiology
It is endemic in parts of Africa (including Transvaal, Uganda, Congo, Nigeria, Ghana, Zimbabwe, Senegal, Burkina Faso, the Central African Republic, Cameroon, Guinea-Bissau), southeast Asia (including Philippines, Malaysia, Cambodia) and the Indian-sub-continent (including Pakistan and southern India).


Incubation Period
The incubation period (time from infection to illness) can be 2-12 days, but is usually 3-7 days. Asymptomatic chikungunya virus infections (infections without illness) do occasionally occur. Chikungunya virus infection is thought to confer life-long immunity. Fatalities related to chikungunya virus are rare.


Signs and Symptoms
Main Clinical Symptoms
  • Fever
  • Arthralgia
  • Myalgia
  • Headache
  • Nausea and vomiting
  • Possibly a rash

Other symptoms
  • Haemorrhagic symptoms: nose and gum bleed (leukopenia)

Complications
  • Meningo-encephalitis
  • Cardiovascular decompensation
  • Respiratory failure

Acute chikungunya fever typically lasts a few days to a few weeks. Additionally, some patients have reported incapacitating joint pain, or arthritis which may last for weeks or months


Prevention and Treament

  • There is no vaccine or specific antiviral treatment currently available for chikungunya fever.
  • Treatment is symptomatic and can include rest, fluids, and anti-inflammatories.
  • Aspirin should be avoided.
  • Infected persons should be protected from further mosquito exposure (staying indoors in areas with screens and/or under a mosquito net) during the first few days of the illness so they can not contribute to the transmission cycle.

Prevention
All medical staff should make sure that he/she applies universal precautions when handling blood samples as patients present with a high viraemia.
Advice should be given to travellers (especially pregnant women, immuno-suppressed and people suffering from a severe chronic illness) visiting the above mentioned countries to:
  • Use anti-mosquito devices (insecticide-treated bed nets, coils, smudge pots, spray, repellents) and wearing long sleeve – long leg clothes, especially during the hours of highest mosquito activity (morning and late afternoon). Mosquito repellents based on 30% DEET concentration is recommended.
  • Before using repellents, pregnant women and children under the age of 12 years should consult a physician or pharmacist 
  • For newborn children under three months repellents are not recommended: instead, insecticide-treated bed nets should be used.

Imported cases
Imported cases have been reported in European countries, mainly France, following return of travellers from these countries. Other countries reporting imported cases include Germany, Switzerland, Italy, Norway and the UK.