What is Chikungunya?
Chikungunya is a fever spread by a chikungunya virus via two species of mosquito of the genus Aedes: A. albopictus and A. aegypti. It is transmitted by the female mosquito.
Modes of Transmission
Chikungunya is generally transmitted from mosquitoes to humans. Less common modes of transmission include vertical transmission, which is transmission from mother to child during pregnancy or at birth. Transmission via infected blood products and through organ donation is also theoretically possible during times of outbreak, though no cases have yet been documented.
Mechanism of Transmission
The virus cannot spread from one human to another but can spread only by mosquitoes which get infected while biting an infected individual, thereafter transmitting the virus by biting an uninfected individual.
Once a mosquito bites, the virus spreads through the epidermal cells of the skin and reaches the inside of the body through the blood stream.
1. The virus primarily targets muscle, joint and skin fibroblasts where the maximum damage occurs. This is the reason why patients experience intense joint pain and swelling along with rashes and acute fever.
2. Apart from the tissues, a person’s immunity-mediated response is another important factor that dictates the severity of the disease. This explains why immune-compromised individuals such as very young children and elderly persons are more severely affected.
3. While Chikungunya results in extreme morbidity and a prolonged phase of physical disability, it is not a fatal disease.
A primary concern with respect to Chikungunya treatment is effective diagnosis.
At present there are no virus-specific detection methods and we have to resort to employing antibody-specific testing which delays diagnosis by a great extent. A study showed that almost 10 per cent of dengue patients were co-infected with the Chikungunya virus but they were not even treated for the disease.
One may argue that dengue is more dangerous than chikungunya due to the complications of dengue as opposed to the non-fatal condition of chikungunya. But one must remember that patient management is quite different for both these infections and has several implications on disease prevention.
Reason why Chikungunya is widespread
The vector plays an extremely important role in the spread of the chikungunya virus. When chikungunya struck in 2005, the reason it was such a huge pandemic was because the virus had mutated its outside coat protein by a single amino acid that allowed it to replicate faster in another species of Aedes.This allowed the vector to transmit the virus more effectively.
Control the key
Whatever be the nature of the virus, the only effective method to control this hugely debilitating infection is intense vector control and public health awareness programmes.
We face multiple issues with respect to chikungunya disease control in our country. A lack of sensitive virus-specific diagnostic tools, an absence of drugs/vaccine, poor vector control measures and public awareness contribute tremendously in escalating the problem. It is no surprise then that India is considered as the hub for chikungunya spread across the globe.