TRACKING EMERGING VIRUSES – October 22, 2025 – Chikungunya
“Chikungunya is spread by the same mosquitoes that transmit dengue and Zika viruses. Symptoms of chikungunya include fever and joint pain, headaches, joint swelling and a rash, according to the U.S. Centers for Disease Control and Prevention. It’s rarely fatal but it can cause severe and debilitating illness. People 65 and older and those with chronic conditions are at higher risk.
Over the summer, the disease exploded in China — an area where chikungunya isn’t endemic. The country recorded more than 16,000 infections in Guangdong province as of Sept. 27, according to the World Health Organization. The outbreak caused the CDC to issue a travel notice for Americans in August.
The virus is endemic in subtropical regions, including parts of the Caribbean, South America and Africa. But as temperatures rose this summer, unusual spots such as Italy and France started seeing infections too.
The threat of mosquito-borne illnesses such as chikungunya and dengue is continuing to grow as a result of climate change. By 2050, the WHO expects 5 billion people will be at risk from mosquito-borne infections as the bugs migrate.” (1)
“CHIKV has now been identified in >110 countries in Asia, Africa, Europe and the Americas. Transmission has been interrupted for several years on islands where a high proportion of the population is infected and then immune; however, transmission often persists in countries where large parts of the population have not yet been infected.
All regions with established populations of Aedes aegypti or Aedes albopictus mosquitoes have now experienced local mosquito-borne transmission.”
“When an uninfected mosquito feeds on a person who has CHIKV circulating in their blood, the mosquito can ingest the virus. The virus then replicates in the mosquito over several days, enters its salivary glands, and can be transmitted into a new human host when the mosquito bites them. The virus again begins to replicate in this newly infected person and reaches high concentrations in their blood, at which point they can further infect other mosquitoes and perpetuate the transmission cycle.” (2)
“Last Monday the World Health Organization warned that drug-resistant bacterial infections are on the rise around the globe. According to the WHO, superbugs that are antimicrobial-resistant, or AMR, contributed to almost five million deaths in 2019 and bore direct responsibility for more than one million. By 2023, one in six laboratory-confirmed bacterial infections showed resistance to antibiotics, with upwards of 40 percent of the medications commonly used in these cases having lost effectiveness over the five years prior.”
“Zooming in on some more localized public health news and some much bigger bugs. New York officials confirmed last Tuesday that a Long Island resident had tested positive for the chikungunya virus. The infected individual, who lives in Nassau County, had reportedly traveled out of the county but not internationally before acquiring the mosquito-borne illness, making this the first reported transmission to occur within the U.S. since 2019.
Chikungunya virus is transmitted by two types of mosquitoes, one of which is present on Long Island.” (3)
“According to the European Center for Disease Prevention and Control, chikungunya is not endemic in mainland EU/EEA. However, since the beginning of 2025, and as of mid-October 2025, two countries in Europe have reported cases of the mosquito-transmitted chikungunya virus disease: France (734) and Italy (364).
Furthermore, in the Communicable disease threats report, week 42, during the past week, France has reported 34 new locally acquired cases of chikungunya virus disease, and Italy has reported 11.” (4)
“By the end of the summer months, people in Cuba, especially in the western end of the island, were wondering what “rare” disease had them bedridden, with body aches and swelling, fevers as high as 40ºC, vomiting, diarrhea, headaches, and even skin blemishes. In Matanzas, the epicenter of the disaster, entire families reported infections, which then spread to every neighborhood, then to the entire province, almost encompassing the entire country. No one knew exactly what it was, and there were barely any reagents in the municipal laboratories that, at the beginning of the outbreak, could confirm what is known today: Cuba is experiencing a combined epidemiological crisis, with the simultaneous presence of dengue, Oropouche fever and chikungunya, which until now the authorities had tried to ignore.” (5)
Mosquito saliva may hold clues to fighting chikungunya inflammation, https://medicalxpress.com/news/2025-10-mosquito-saliva-clues-chikungunya-inflammation.html
1.Mosquito-borne disease troubling Asia and the Caribbean hits New York, By Jessica Nix, https://www.latimes.com/science/story/2025-10-21/mosquito-borne-disease-in-asia-and-the-caribbean-hits-new-york
2.Chikungunya, https://www.who.int/news-room/fact-sheets/detail/chikungunya
3.Global Superbugs Surge, Chikungunya Hits Long Island, By Rachel Feltman, Fonda Mwangi, Jeffery DelViscio & Alex Sugiura, https://www.scientificamerican.com/podcast/episode/who-reports-global-rise-in-antibiotic-resistance-and-superbug-deaths/
4.Chikungunya Cases Spike in France and Italy, by Don Hackett, https://www.vax-before-travel.com/2025/10/19/chikungunya-cases-spike-france-and-italy
5.Dengue, Oropouche fever, chikungunya: an epidemiological crisis has Cuba on edge, Carla Gloria Colomé, https://english.elpais.com/international/2025-10-16/dengue-oropouche-fever-chikungunya-an-epidemiological-crisis-has-cuba-on-edge.html
curated by Jonathan M. Metsch, Dr.P.H.
Clinical Professor of Environmental Medicine, Icahn School of Medicine at Mount Sinai