Home Forums Other Specialities General Topics Chikungunya – The Facts

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      Anonymous
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      Chikungunya is one of a group of arboviruses and is transmitted by Aedes group of mosquitoes which normally fly around during daytime. It was first described in southern Tanzania in 1952. Its name derives from the Kimakonde language, meaning “to become contorted”, referring to the sufferer’s stooped posture caused by joint pains.

      Epidemiology
      Chikungunya fever occurs in both sporadic outbreaks and large epidemics in Africa, the Indian subcontinent and Southeast Asia, particularly the Philippines, Thailand, Cambodia, Vietnam, Mauritius and Sri Lanka. It affects all age groups but more than 50% are over the age of 65 years – of which a third will die. Severe illness also occurs in children.

      It has also been reported in south-eastern France and Italy. There was an exceptionally virulent outbreak in the French island of La Réunion in the Indian Ocean, in 2005 and 2006, which also affected neighbouring islands, including Mauritius.
      It is said to affect thousands of people throughout the world every year.
      The disease is sometimes imported in to the European countries by travellers returning from endemic areas. The number of reported cases for the UK in 2010 was 79 – an increase by 34% compared with 2009 (the majority was imported from India).

      Risk factors
      Risk is highest in the rainy season when numbers of mosquitoes are at their greatest.

      Presentation
      The illness characteristically begins with rapid onset of joint pains and may or may not be accompanied by muscle pain, high fever, conjunctivitis and a rash.

      Incubation period is 2-4 days.
      There is sudden onset of fever and, with it, a severe, crippling migrating, polyarticular arthritis. This is due to the virus invading and causing inflammation of the cartilage.
      Between the 2nd and 5th day of illness there is a macular or maculopapular rash, mostly on the trunk and limbs.
      There may be conjunctivitis and minor bleeding in the skin and eye.
      Patients may also develop hepatomegaly.

      In children, blindness due to retrobulbar neuritis, and acute flaccid paralysis, have been described.
      Other features include meningo-encephalitis, cardiovascular decompensation, or respiratory failure.
      Most patients recover within a few days and death is a rarity. Arthritis may persist for rather longer, even several months or years.

      Investigations
      Serological testing, eg enzyme-linked immunosorbent assays, can be used to confirm the diagnosis. More recently, indirect immunofluorescence has become available. Reverse transcriptase-polymerase chain reaction can also be used but the sensitivity is variable. Extreme care should be taken when obtaining blood samples and handling specimens.

      Differential diagnosis
      The picture may be confused with the various viral haemorrhagic fevers or malaria.

      Chikungunya is very similar in presentation to dengue fever. The main differences are:

      In classical dengue fever there is no hepatomegaly whilst that is present in Chikungunya and haemorrhagic dengue fever.
      In haemorrhagic dengue fever there is also a confluent petechial rash.

      Management
      The management largely revolves around symptom relief.
      Fever is marked and especially in a hot environment, plenty of fluid should be drunk.
      Paracetamol and ibuprofen may help to relieve pyrexia and pain.
      Sometimes chloroquine is used for persistent arthritis. This is based on a pilot study in 1984 that has not been repeated since.

      Complications
      The relationship between malaria, glandular fever and Burkitt’s lymphoma is well known, but the distribution in Africa may mirror that of Chikungunya fever too.

      Prognosis
      The majority of patients will recover but some may be left with chronic joint pains which may last several years. Chikungunya virus does not cause death directly but in the presence of other comorbidities it may contribute to a fatal outcome. This disease is notifiable in the UK.

      Prevention
      Epidemics have been associated with poor control of mosquitoes. Prevention requires the use of insect repellents and elimination of breeding places for mosquitoes, eg stagnant water. There is no vaccine available.

      This article was extracted from Egton Medical Information Systems Limited through their website “Patient”

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