CHIKUNGUNYA
What is Chikungunya
How do humans become infected with chikungunya virus?
What are the symptoms?
How is it diagnosed?
How is it treated?
How to prevent Chikungunya?
What is Chikungunya?
Chikungunya is a relatively rare form of viral fever caused by an alphavirus
that is spread by mosquito bites from the Aedes aegypti mosquito. The
name is derived from the African word meaning ‘that which bends up’ in
reference to the stooped posture developed as a result of the arthritic
symptoms of the disease. The disease was first described by Marion Robinson and
W.H.R. Lumsden in 1955, following an outbreak on the Makonde Plateau, along the
border between
Epidemiology
Chikungunya was first described in
There have also been cases in
A separate outbreak of chikungunya fever was reported from
Analysis of the recent outbreak has suggested that the increased severity of
the disease may be due to a change in the genetic sequence, altering the virus'
coat protein, which potentially allows it to multiply more easily in mosquito
cells.
How do humans become infected with chikungunya virus?
The chikungunya virus is spread by the bite of an infected mosquito. Mosquitoes
become infected when they feed on a person infected with the chikungunya virus.
Monkeys, and possibly other wild animals, may also serve as reservoirs of the
virus. Infected mosquitoes can then spread the virus to other humans when they
bite.
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) may also play a role in human transmission is
What are the symptoms?
After an incubation period of 3-12 days there is a sudden onset of flu-like
symptoms including a severe headache, chills, fever (>40°C, 104°F), joint
pain, nausea, vomiting and a rash involving the limbs and trunk. The joints of
the extremities in particular become swollen and painful to the touch.
Haemorrhage is rare and all but a few patients recover within 3-5 days. There
can also be headache, conjunctival injection and slight photophobia. Some can
suffer for joint pain for months. Children may display neurological symptoms.
How is it diagnosed?
Sudden severe headache, chills, fever, joint and muscle pain are the commonest
symptoms. The diagnostic tests include detection of antigens or antibodies in
the blood, using ELISA (or EIA - enzyme immunoassay) or molecular techniques
like polymerase chain reaction (PCR). The antibodies detected by serological
assays like ELISA require an IgM capture assay to distinguish it from dengue
fever.
How is it treated?
While supportive or palliative medical care with anti-inflammatory drugs and
analgesics is available, there is no specific treatment for chikungunya. The
illness is usually self-limiting and resolves with time. Symptomatic treatment
is recommended after excluding other more dangerous diseases. Analgesics, antipyretics
and fluid supplementation are important aspects in managing this infection.
There is no vaccine currently available.
The virus can be killed by common disinfectants, moist heat and drying. The
vector (a mosquito) also needs to be controlled with insecticides.
How to prevent Chikungunya?
Prevention is possible by controlling proliferation of mosquitoes in stagnant
water. Water collection should be avoided by:
Other
precautions: