What is the risk of Chikungunya ?

Chikungunya is a vector-borne disease. This means that the chikungunya virus is transmitted by a living organism to humans thereby causing illness – in the case of chikungunya, the vector that transmits the virus to humans is the Aedes mosquito. Aedes mosquitoes are also vectors for dengue, yellow fever and zika viruses, all of which can cause epidemics. Therefore, the Aedes Mosquito is of significant interest for public health, in particular for the preparedness and prevention of epidemics and pandemics.

Currently, almost 4 billion people are at risk globally for Aedes-borne viruses such as dengue, chikungunya and Zika. This number continues to increase because the habitat of the Aedes mosquito is expanding due to climate change and urbanization. Aedes mosquitos favor warmer climates and urban settings where there are ample protected spaces to hide, such as under tables and in curtains, and collections of still, relatively clean water in which to breed. Even in areas where there have been previous epidemics of Chikungunya, such as in the Americas since 2013,?population level immunity is not high enough to prevent current outbreaks. The virus is spreading into new areas that had previously been spared. This increase, in the Americas, of chikungunya and other Aedes-borne diseases such as dengue is worrying - the number of chikungunya cases reported in the first four months of 2023 already surpasses the annual number of cases reported by year from 2017-2022.

Even though the mortality associated with chikungunya is low, the patient does experience severe joint pain and related disability that can persist for months. The impact of the disease is therefore high as the acute illness, followed by chronic disabilities related to joint pain and mobility, can significantly affect a person’s ability to move, work, and take care of themselves and others. In addition, there is the impact on the health system. Given the scale of the current outbreak in some countries in the Americas, a relatively low proportion of cases at risk of severe disease, translates into a large number of patients that require care in health care facilities.

The current localized outbreaks of chikungunya should be seen as opportunities to learn about vector-borne diseases to improve our preparedness for them and to refine the methods of prevention. As with other vector-borne diseases preparedness requires an understanding of the vector, its habits and habitats – it will then be possible to predict which geographic areas might be at increasing risk and to take measures to reduce “mosquito-friendly” spaces. Prevention includes avoiding mosquito bites through the use of appropriate clothing that covers most of the body, mosquito repellents and use of bed nets. Furthermore, healthcare systems can increase their capacities to diagnose and?treat chikungunya as early as possible while also providing support to patients suffering from long term consequences of the disease.

The EPI WIN webinar allowed us to exchange views, share information and improve our collective understanding of the risk. visit our EPIWIN site to access the recordings and the slide sets.

Thanks to Sarah Hess for her contribution to this article, to Supriya Bezbaruah and Lujbica Latinovic for organizing the webinar.