What Is Chikungunya Virus Infection

Chikungunya virus infection is a mosquito-borne disease that causes sudden fever and severe joint pain. This viral illness has become a growing concern worldwide, particularly after recent alerts issued by health authorities like the World Health Organization. Chikungunya virus infection is transmitted mainly by two types of mosquitoes and is spreading in regions where these mosquitoes thrive.

This week, the World Health Organization raised concerns about a surge in the number of cases of a mosquito-borne viral illness known as chikungunya virus infection. A growing outbreak has been recorded in La Réunion and Mayotte, islands in the Indian Ocean that were hit hard by a previous epidemic in 2004 to 2005. Between August 2024 and May 2025, over 47,500 confirmed cases and 12 deaths have been reported in La Réunion alone.

More than 100 countries have now seen local transmission of this virus, including locations across Africa, Asia, and Europe. The WHO warns that due to global travel and changing mosquito habitats, more regions may experience outbreaks in the near future.

Symptoms of Chikungunya Virus Infection

The hallmark symptoms of chikungunya virus infection include fever and joint pain. These symptoms usually begin three to seven days after being bitten by an infected mosquito, but in some cases, they may take up to 12 days to appear. The illness often starts abruptly and can be mistaken for other viral infections, especially in regions where dengue fever is also common.

In addition to fever and joint swelling, individuals may experience:

• Headache
• Rash
• Muscle pain
• Nausea
• Fatigue

Although most people recover within a few weeks, chikungunya virus infection can sometimes lead to prolonged fatigue and joint discomfort. In rare cases, the disease may be fatal, especially for infants, the elderly, and individuals with underlying health conditions.

How Chikungunya Virus Infection Spreads

The spread of chikungunya virus infection occurs through the bite of infected female mosquitoes. The two main species responsible are Aedes aegypti and Aedes albopictus. These mosquitoes acquire the virus by feeding on an infected person. Once infected, the virus multiplies inside the mosquito and becomes transmissible to humans during subsequent bites.

Unlike many other mosquito species, these mosquitoes are active during the daytime. They are commonly referred to as “ankle biters” because they often bite around the lower legs. They are aggressive feeders and may bite multiple people in a short period.

These two mosquito species are also known to transmit other viral infections such as:

• Dengue virus
• Yellow fever virus
• Zika virus

The presence of chikungunya virus infection in areas where these mosquitoes thrive raises concerns about future outbreaks, especially in warmer regions and areas with inadequate mosquito control efforts.

Regions Affected by Chikungunya Virus Infection

Chikungunya virus infection was first identified in 1952 in Tanzania. For many decades, outbreaks were limited to parts of Africa and Asia. However, with increasing international travel, urbanisation, and climate change affecting mosquito populations, the virus has now spread globally.

As of December 2024, local transmission of chikungunya virus infection had been confirmed in at least 119 countries and territories. One of the largest epidemics occurred between 2004 and 2005, starting in the Indian Ocean islands and eventually affecting hundreds of thousands of individuals in India.

Recent WHO alerts have highlighted the following areas:

• La Réunion: Over 47,500 confirmed cases between August 2024 and May 2025
• Mayotte: 116 cases reported from March to May 2025
• Africa, Asia, and parts of Europe: New outbreaks reported in multiple locations

The virus’s ability to spread quickly in tropical and subtropical regions makes it a continuing global health concern.

Mosquito Species Involved in Chikungunya Virus Infection

Two key species are responsible for transmitting chikungunya virus infection: Aedes aegypti and Aedes albopictus. Both species are prevalent in warm climates and urban areas.

These mosquitoes are small, typically around 4 to 7 millimetres in size. They can be recognised by their black-and-white striped legs and markings on the thorax. Since they are active during daylight hours, they often go unnoticed by people who associate mosquito bites with evening or nighttime.

The Aedes mosquitoes thrive in environments with standing water such as:

• Flowerpots
• Water tanks
• Discarded containers
• Clogged gutters

Controlling these breeding grounds is essential to reduce the risk of chikungunya virus infection outbreaks.

Diagnosis and Treatment of Chikungunya Virus Infection

There is no specific antiviral treatment for chikungunya virus infection. Doctors usually diagnose the illness based on symptoms and recent travel history, especially if the patient has visited a region where outbreaks are occurring.

Laboratory tests such as blood tests can confirm the presence of the virus. However, in many outbreak settings, treatment begins before confirmation due to the distinct clinical presentation.

Treatment options include:

• Rest and hydration
• Medications such as paracetamol to relieve fever and joint pain
• Avoiding anti-inflammatory drugs until dengue is ruled out

Because of the risk of co-infection with other mosquito-borne diseases, especially in tropical areas, healthcare providers often take extra precautions before prescribing any medication.

Preventing Chikungunya Virus Infection

Prevention remains the most effective strategy for managing chikungunya virus infection. As there is no vaccine available for public use, reducing mosquito bites is critical.

Steps to prevent infection include:

• Using insect repellent on exposed skin
• Wearing long-sleeved clothing and pants, especially during the day
• Sleeping under mosquito nets if living in or visiting affected regions
• Eliminating standing water where mosquitoes can breed
• Installing window screens to keep mosquitoes out of homes

In high-risk regions, public health campaigns and community-based mosquito control programs play a vital role in reducing the spread of chikungunya virus infection.

Current Global Outlook on Chikungunya Virus Infection

The rise in cases reported by WHO in 2025 underlines the need for increased awareness and better mosquito control strategies. Although Australia has not experienced widespread outbreaks, imported cases remain a concern due to global travel. Public health authorities continue to monitor the situation closely.

With chikungunya virus infection now present in over 100 countries, and new cases emerging in places where the virus had not previously been found, global health agencies are urging vigilance. As the virus spreads alongside climate changes and urbanisation, more regions could face outbreaks in the future.