Chikungunya virus

The Chikungunya virus is a tiny pathogen that can make people sick. It is not passed from person to person, but through the bite of certain mosquitoes. Those who become infected usually develop high fever and very severe joint pain after three to seven days. The name comes from a language spoken in Tanzania and roughly means “that which bends up” or “the one who walks bent over.” This refers to the fact that the pain forces those affected into a stooped posture. The disease is rarely fatal, but its effects can linger for many months.

Why the virus keeps spreading further

Chikungunya was long considered a problem of tropical countries in Africa and Asia. That has changed. The tiger mosquito, one of the two main transmitters, now also lives in Italy, France, Spain, and parts of southern Germany. It reached Europe via tire and plant shipments and has established itself there. Warmer summers help it further, since the virus only multiplies within the mosquito when there is sufficient warmth.

As a result, local outbreaks have been appearing in Europe for several years. A traveler carries the virus in their blood, a local mosquito bites them, and then transmits it to neighbors. In Italy and France, there have already been several hundred such cases without any travel abroad. Health authorities are watching this closely, because a new disease can quickly affect many people in a population with no immunity at all.

Chikungunya is also economically relevant. Large outbreaks incapacitate workers for weeks and put a strain on tourism regions. On Réunion, about a third of the island’s population fell ill in 2005 and 2006. Since 2023, the first vaccines have been approved, which is also relevant for pharmaceutical companies and their investors.

From mosquito bite to joint pain

The cycle begins with an infected person. If a mosquito bites them, it picks up the virus along with the blood. Inside the mosquito’s body, the virus multiplies over about a week and migrates to the salivary glands. If the mosquito then bites another person, the virus enters that person’s blood via the saliva. You can think of it as a flying syringe connecting two people one after another.

Inside the human body, the virus primarily attacks cells in the skin, muscles, and joints. The immune system reacts fiercely, and it is precisely this immune response that causes the fever and pain. Swollen hands, feet, and knees are typical, often on both sides of the body at once. Many patients also experience skin rash and headaches.

There is no medication against the virus itself. Only the symptoms are treated, for instance with fever-reducing medication and plenty of fluids. After surviving an infection, one is presumably protected for life. In some patients, however, the joint pain persists for months or even years. This is the most important difference from the Dengue virus, which is transmitted by the same mosquitoes: Dengue is more dangerous, but Chikungunya is more prolonged.

Chikungunya in travel warnings and the news

Most commonly, the term appears in travel advisories from the German Federal Foreign Office. For countries in Southeast Asia, South America, the Caribbean, and East Africa, a warning notice about Chikungunya regularly appears there. The recommended protective measure is always the same: long clothing, mosquito repellent on the skin, and mosquito nets. Unlike the malaria mosquito, the tiger mosquito bites mainly during the day.

In the news, the virus usually comes up on two occasions. Either there is a major outbreak, as recently seen in the Indian Ocean region and parts of Asia. Or it concerns vaccines: since 2023, two preparations have been approved in the US and Europe, recommended especially for travelers and older people in risk areas.

A common misconception is that Chikungunya is contagious like the flu. That is not true. Without a mosquito, there is practically no transmission; coughing or shaking hands play no role. Anyone returning from a risk area who develops a fever should still see a doctor. The symptoms resemble those of malaria and Dengue, and only a blood test can provide clarity.