Daily Times

Pakistan, similar to other Asian countries, is facing significant climate changes. Summers are becoming more intense, while winters are turning milder every passing year. The rising temperatures have led to a rise in arboviral diseases such as malaria and dengue. In addition, inadequate sanitation across much of Asia creates optimal breeding conditions for the arthropod vectors that spread these diseases.

Chikungunya is a viral illness spread by mosquitoes, caused by the chikungunya virus (CHIKV), an RNA virus in the alphavirus genus of the Togaviridae family. The term ‘chikungunya’ comes from the Kimakonde language and means ‘to become contorted.’ This disease is mainly transmitted by mosquitoes like Aedes aegypti and Aedes albopictus, which also carry dengue and Zika viruses. Chikungunya is widespread in Africa, Asia, and the Americas, with occasional outbreaks in other regions. These mosquitoes usually bite during the day and lay their eggs in containers of standing water.

The chikungunya virus transmission cycle starts when an uninfected mosquito bites a person who is infected with the virus. Inside the mosquito, the virus replicates and eventually reaches the salivary glands. When the mosquito bites another human, it transmits the virus, which then replicates in the new host. This leads to high levels of the virus in the host’s blood, perpetuating the cycle of transmission.

Travellers to regions with active chikungunya transmission should follow basic precautions.

Chikungunya presents symptoms similar to those of dengue and Zika, which can lead to misdiagnosis. The illness generally causes fever and severe joint pain that can be debilitating and last for varying durations. Other symptoms include joint swelling, muscle pain, headache, nausea, fatigue, and rash. Symptoms typically appear 4 to 8 days after a mosquito bite, though they can develop anywhere from 2 to 12 days later. While joint pain is usually temporary, it can persist for weeks, months, or even years. In milder cases where joint pain is minimal, the infection might go unnoticed.

Most people recover completely from chikungunya, but in rare instances, complications involving the eyes, heart, or nervous system have been reported. Individuals at the extremes of age, especially new-borns infected during childbirth and elderly people with pre-existing health conditions, face a higher risk of severe illness. In such cases, chikungunya virus infections can elevate the risk of mortality.

After recovery, individuals are thought to gain immunity against future chikungunya infections. However, there is no licensed vaccine or specific treatment available for the disease. The true number of cases is likely underestimated due to difficulties in diagnosis and reporting. Severe symptoms and fatalities are rare and usually occur alongside other health conditions.

The chikungunya virus can be identified in blood samples during the first week of illness using tests like reverse transcriptase-polymerase chain reaction (RT-PCR). Additionally, antibody tests can detect the presence of antibodies, which generally become visible within the first week of infection and may remain detectable for up to two months.

Clinical management of chikungunya primarily aims to alleviate fever and joint pain using antipyretics and suitable analgesics, while also ensuring adequate hydration and rest. As there are no antiviral treatments available for CHIKV infections, paracetamol (acetaminophen) is advised to reduce pain and fever until dengue is excluded. Non-steroidal anti-inflammatory drugs (NSAIDs) are generally avoided, as they can increase the risk of bleeding.

As of December 2022, several vaccines are in development, but none are yet licensed. Prevention of chikungunya primarily involves avoiding mosquito bites. Individuals suspected of having the infection should take precautions to prevent mosquito bites during the first week of illness to help reduce transmission.

The main approach to controlling CHIKV transmission involves reducing mosquito populations, which necessitates active community participation. Key efforts should include eliminating standing water in containers, proper waste disposal, and supporting local mosquito control programs. During outbreaks, insecticides may be used to kill adult mosquitoes, applied to surfaces where mosquitoes rest, or introduced into water containers to target larvae. Health authorities might also implement these measures as emergency interventions.

For personal protection during outbreaks, individuals should wear clothing that covers as much skin as possible, install screens on windows and doors, and apply insect repellents containing DEET, IR3535, or icaridin. Those who sleep during the day, including children, the ill, or the elderly, should use insecticide-treated mosquito nets.

Travellers to regions with active chikungunya transmission should follow basic precautions, such as using insect repellents, wearing long sleeves and pants, and ensuring their accommodations have screens to prevent mosquitoes from entering.

The writer is a Paediatrician and Fatima Jinnah Medical University alumna, currently working at the Pakistan Institute of Medical Sciences (PIMS), Islamabad.