NEWS This summer, the World Health Organization, WHO, has appealed to prevent a repeat of an epidemic of the chikungunya virus, that swept the world twenty years ago. Let us learn more by asking Lars-Anders Carlson, Associate Professor at Umeå University, five questions.
Lars-Anders Carlson's group at Umeå University is doing research on the chikungunya virus.
ImageMattias PetterssonLuckily, the mosquitos we have in Sweden do not carry the virus
The cause for concern is new outbreaks reported in the Americas, Africa, Asia, and Europe (France and Italy). A major outbreak is underway in China, especially in the southern part. The most common symptoms of chikungunya virus infection are fever and muscle and joint pain. Chikungunya virus is spread to humans by infected mosquitoes and cannot be spread directly from person to person.
The infection is caused by a virus belonging to the alphavirus group. It creates “factories” on the cell surface where its genes are copied when the virus infects a cell. Lars-Anders Carlson's research group wants to understand how these viral factories work, to ultimately help in the efforts to design new antiviral strategies.
“Yes, the virus is contagious, but only if you get bitten by an infected mosquito. Luckily, the mosquitos we have in Sweden do not carry the virus!”
“The virus spread through bites by mosquitos of the genus Aedes. Some twenty years ago, it seemed like Chikungunya virus was primarily spread by Aedes aegypti, a tropical mosquito. But in 2006, a massive outbreak took place on the island La Réunion, and scientists could show that the virus, with a minimal mutation, had adapted itself to a new mosquito species, Aedes albopictus. This mosquito, which is known as the Asian tiger mosquito, is more widely spread, which allowed chikungunya virus to also spread more widely, for example to Southern Europe.”
“Most infections are probably mild, but this is hard to know exactly since many infections probably go undiagnosed. But infections can become more severe. The most devastating consequence is probably severe joint pain which can last for several months. There are also rare reports of chikungunya-caused encephalitis.”
“As of very recently (2024) there is actually a vaccine, called Ixchiq. It is based on Swedish research from Karolinska Institutet. It is very exciting to see some progress on this. Unfortunately, there is now a temporary restriction on giving this vaccine to people older than 65 due to some side effects observed, so we will see how it develops.”
“That is not my expertise, but my understanding is that it probably will not come here any time soon. However, the Aedes mosquitos are slowly moving up from southern to middle Europe, and only this year I saw that they may expect chikungunya infections in southern Germany.”
“A related virus called Sindbis virus can sometimes be spread by Nordic mosquitos to cause what in Swedish is called “Ockelbosjukan”, which resembles a milder chikungunya fever. The Norwegians have a fun name for this – they call it bærplukkersyken, the berry-pickers disease.”
“I am interested in some very fundamental aspects of the virus factories that the virus creates to copy its genes. This machinery is fascinating to me! We are using electron microscopy to create detailed tree-dimensional images of the virus factories and use these images to gradually understand how the factories work. Eventually this might allow us to see how the virus copies its genes at the resolution of individual atoms. We are not quite there yet, so some work remains. Eventually, I think we can get a complete understanding of how they work!”