Chikungunya Cases Set Unfortunate Records in 2024

Over ten years ago, the Pan American Health Organization (PAHO) urged its member countries with mosquitoes that transmit the chikungunya virus (CHIKV) to increase their vector control programs before infections become endemic.

Since then, 15 countries in the Region of the Americas have reported mosquito-transmitted chikungunya outbreaks in 2024, setting recent highs for cases and related fatalities.

As of October 18, 2024, the PAHO reported over 402,590 CHIKV cases and 180 related deaths in the Americas this year. 

This PAHO data compared with just 376,850 CHIKV cases reported for all of 2023. 

Furthermore, the United States is reporting increasing travel-related chikungunya cases. 

As of October 12, 2024 (Week 41), the U.S. Centers for Disease Control and Prevention (CDC) says international travelers are most at risk when visiting areas experiencing ongoing epidemics.

The CDC reported 131 chikungunya cases in Territories and non-U.S. residents in 2024, led by Massachusetts (18). Along the southern border, the Texas Department of State Health Services has reported (11) chikungunya cases this year.

The CDC reported only 118 chikungunya cases nationwide last year.

According to the CDC's Yellow Book 2024, evidence demonstrates that CHIKV infection produces lifelong immunity. This means the disease can be acquired only once because antibodies protect people against future infections.

However, the CDC says mosquito bites are not the only method of virus transmission.

Maternal-fetal transmission has been documented during pregnancy, with the most significant risk occurring in the perinatal period when the pregnant person is viremic at the time of delivery.

Although chikungunya viral RNA was identified in the breast milk of an infected woman, the breastfed infant had no symptoms or evidence of infection based on laboratory testing.

Additionally, chikungunya viral RNA has been identified in semen, but no evidence of sexual transmission has been noted to date.

Moreover, in September 2024, an Original Article reported even after a year, chikungunya fever-affected people experience damage to their physical and mental health, positive screening for depression risk was 13.5 times more likely in chronically affected, and patients with chronic chikungunya fever 76 times higher risk of walking impairments.

From a disease prevention perspective, the CDC reported positive news in 2023, when the U.S. FDA approved the first chikungunya vaccine.

Furthermore, other areas in the Americas are taking action as well.

For example, the U.S. V.I. Department of Health announced on October 2, 2024, that it encourages everyone (St. Croix, St. Johns, St. Thomas) to protect themselves from Chikungunya in October.

"Vaccination is a crucial step in protecting our community from chikungunya," said VI Health Commissioner Justa Encarnacion in a press release. "With the increase in dengue cases, we must remain vigilant and do everything we can to safeguard our health."

As of October 18, 2024, the U.S. FDA-approved chikungunya vaccine is offered at various travel clinics and pharmacies in the U.S.