Conditions of locality more important than climate in chikungunya outbreaks, shows analysis

New Delhi, Oct 6 (PTI) Conditions such as housing quality, mosquito numbers and response of a community could help in predicting severity of a chikungunya outbreak in a locality, a new analysis of 86 past outbreaks including those in India have found.

The findings published in the journal Science Advances also show that climate conditions -- temperature and rainfall -- are not the most important factor when trying to predict the severity of the infectious disease outbreak, caused by spread of the chikungunya virus through mosquito bites.

Researchers, including those at the University of Notre Dame, US said innovative approaches that look beyond climate factors for predicting an outbreak's severity or spread are required.

Symptoms of the viral infection can include high fever and severe joint pain, with around 50 per cent of the affected estimated to suffer from long-term conditions of pain and disability.

The team reconstructed and analysed 86 chikungunya outbreaks, including the 2006 outbreak in India's Port Blair, "creating the largest comparative dataset of its kind." "Climate factors like temperature and rainfall can tell us where outbreaks are possible, but this study shows that they don't help very much in predicting how severe an outbreak will be," co-author Alex Perkins, professor of infectious disease epidemiology in the department of biological sciences at the University of Notre Dame, said.

"Conditions of a locality conditions matter -- things like housing quality, mosquito density and how communities respond. Some variation is simply due to chance. That randomness is part of the story too," Perkins added.

India is estimated to be bear the greatest brunt of chikungunya in the long-term, with a study, recently published in the British Medical Journal (BMJ) Global Health, suggesting that 51 lakh people are at the risk of infection every year.

No specific treatments currently exist for the viral mosquito-borne infection, even as two preventive vaccines have been approved for use in certain countries, including the US. However, the vaccines are not widely available in regions where the virus is most common, the researchers said.

They further said the study can help in making accurate predictions of where an outbreak might occur before it happens, thereby plan trials and monitor whether candidate vaccines are effective and aiding in vaccine development.

The study demonstrates how a more comprehensive analysis of past outbreaks can help public health officials prepare for future outbreaks, protecting vulnerable populations and aiding vaccine development, the team said.

"Additional data on vector control efforts, housing quality, and urbanness may be particularly useful for improving estimates of (transmissibility ratio) although these are typically less readily available than climatic variables," they wrote. PTI KRS KRS OZ OZ