Pacific Island countries are experiencing record-high dengue infections, a sign of the health consequences climate change may bring worldwide.
Confirmed Cases Across Pacific Islands
Since the start of the year, more than 16,500 dengue cases have been confirmed on Pacific islands, resulting in 17 deaths. Fiji, Samoa, and Tonga now report the highest infection rates in the decade.
Fiji’s weekly case numbers are three times higher than the five-year average, while Samoa has seen a dramatic rise from only a few dozen cases per week last year to over 1,300 by mid-year, according to WHO data.
Dengue is caused by a virus transmitted by Aedes mosquitoes, leading to high fever, muscle and joint pains, headaches, and rash. The disease can be fatal, especially without proper treatment. Although a vaccine has been available for a short time, its limited use—only one of two vaccines is recommended for individuals who have previously been infected—prevents widespread deployment.
Climate Change Fuels Rising Cases
Experts link the significant increase in infections to climate change. The Guardian reports that dengue was previously a seasonal disease, but warming now extends the virus transmission period. In some areas, dengue risk has become year-round, notes Dr. Paula Vivili of the Pacific Community.
Aedes mosquitoes, including the tiger and albopictus species, thrive as temperatures and humidity rise, and with stronger rainfall creating more breeding sites. Global warming not only raises temperatures but also increases atmospheric moisture, leading to more intense storms that further encourage mosquito multiplication.
A Grim Forecast for the Future
Dr. Joel Kaufman, an epidemiologist at the University of Washington, described dengue as one of the first diseases whose spread we can unequivocally attribute to climate change. Heavy rains can create standing water, providing additional breeding grounds for mosquitoes.
This situation threatens island residents—already among the most affected by climate change—and serves as an ominous warning for other regions worldwide. Kaufman warned that diseases linked to temperature increases will likely become more frequent and severe.
Implications for Poland
While mosquitoes carrying malaria and dengue may spread in Poland as the climate warms, the country is not currently at risk for these viruses. However, climate change does influence the spread of tick-borne diseases. Last year Poland recorded a record number of Lyme disease cases, with over 29,300 diagnoses—a 16% increase from the previous year. Over the past 15 years, Lyme cases have steadily risen, except during the pandemic years when healthcare services were strained.
Ticks were once considered a seasonal threat, active only from spring to fall. Higher temperatures now prolong tick activity, potentially extending into winter, experts noted, further increasing Lyme disease incidence.
