Discovery may lead to better treatment for chikungunya

Aedes mosquitoes are vectors for the chikungunya virus

Flickr/eyeweed

[MANILA] A blood protein has been discovered by a Singapore-based team of scientists that can help identify at an early stage those patients suffering from chikungunya fever who are likely to develop a severe form of the disease.

The discovery of this protein means that doctors can provide more targeted care at the very start of the disease. The finding also paves the way for the potential development of an effective and safe vaccine.

Chikungunya, which means 'that which bends up' in the Makonde language of Southern Africa, is so named because infected patients, who suffer from severe muscle and joint pains, often develop a contorted posture.

The viral disease is transmitted by infected Aedes mosquitoes, and has symptoms similar to dengue fever. It typically lasts from five to seven days, although full recovery may take months, depending on severity.

Outbreaks have occurred in Africa, India and in several South-East Asian countries, including Indonesia, Singapore and Thailand. One of the biggest outbreaks was reported in La Reunion Island in 2006 with over 100,000 people infected and 200 reported deaths. At present no vaccines are available, and treatment often involves only the relief of symptoms.

Last month, two scientific journals, The Journal of Infectious Diseases and EMBO Molecular Medicine, published a breakthrough in chikungunya research which is expected to improve the treatment of those suffering from the mosquito-borne disease.

Scientists from the Singapore Immunology Network (SIgN), a research consortium under the Agency for Science, Technology and Research (A*STAR) discovered that blood protein known as Immunoglobulin G3 (IgG3) antibodies can be used to identify patients with higher risk of the more serious form of chikungunya fever.

Virologist Lisa Ng, principal investigator at SIgN, told SciDev.Net that the discovery "will allow for more cost-effective patient management".

The patients who responded to the disease at the onset with high levels of the IgG3 antibody were found to be unlikely to develop a more severe form of chikungunya fever.

In contrast, those with a delayed IgG3 response were generally found to have less acute symptoms at the start, but to be more susceptible to chronic debilitating joint pains at later stage of the disease.

SIgN's research on chikunguya began when an outbreak hit Singapore four years ago.

Chikungunya-infected patients at Singapore's Tan Tock Seng Hospital were recruited to take part in the research initiated by Ng — who was instrumental in identifying the SARS virus in the 2003 — in collaboration with clinician-scientists Leo Yee Sin and Angela Chow.  

Ng's team found a specific part of a chikungunya protein, named E2EP3, that triggers an immune response and creation of protective antibodies.

They then tested this molecule as a vaccine in mice and found that it significantly reduced the number of viruses and joint pain, which makes it a candidate for future vaccines.

Ng said that the researchers are now seeking to confirm their findings with researchers from other countries where the virus outbreaks have been reported.

Link to full article in The Journal of Infectious Diseases

Link to full article in EMBO Molecular Medicine