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Following a decrease in Dengue fever cases in 2025, the global risk may be rising again in 2026 across the Americas, Asia, Africa, and the Pacific.
According to the U.S. Centers for Disease Control and Prevention (CDC) Global Dengue Travel Health Notice, updated on January 22, 2026, eleven countries are reporting higher-than-usual Dengue activity or elevated cases among U.S. travelers returning from these destinations.
These countries include Afghanistan, Bangladesh, Colombia, the Cook Islands (New Zealand), Cuba, Mali, Mauritania, Nicaragua, Samoa, Sudan, and Vietnam.
The CDC has flagged these nations based on public health data showing surges or sustained transmission. Travelers to these locations may face increased exposure, particularly during warmer, wetter seasons that favor mosquito breeding.
This updated Notice, classified as Level 1, states that Dengue, a mosquito-borne viral illness primarily spread by Aedes species mosquitoes, remains a year-round threat in many tropical and subtropical regions.
Outbreaks typically occur every 2-5 years. Dengue symptoms include high fever, severe headache, pain behind the eyes, joint and muscle pain, rash, and, in severe cases, potentially life-threatening complications such as Dengue hemorrhagic fever.
In the United States, Florida continues to be an unfortunate leader in reporting Dengue cases.
Three cases of Dengue were reported in January 2026 in persons who had international travel. In 2025, 429 cases of Dengue fever were reported among individuals who had traveled internationally, with 311 cases among travelers from Cuba and 21 from Puerto Rico.
Additionally, in 2025, 62 locally acquired Dengue cases were reported in Florida.
There is currently no specific treatment available in the U.S., so the CDC advises anyone planning to travel to dengue-risk areas to take standard precautions against mosquito bites, as there is no universal vaccine recommended for most travelers.
As of January 23, 2026, second and third-generation (Butantan-DV) Dengue vaccines are available in select countries, but not in the continental U.S.
The state of North Carolina is currently experiencing a measles outbreak, with 11 confirmed cases since late December 2025, according to the North Carolina Department of Health and Human Services (NCDHHS).
As of January 23, 2026, health officials describe these cases as "embers" from a larger outbreak in South Carolina, where over 600 cases have been reported, mainly around Spartanburg County.
The NCDHHS measles dashboard indicates that cases are primarily in the western regions, with Buncombe County having the most cases (6), followed by Polk County (2), Cabarrus County (2), and Rutherford County (1).
Epidemiologists have noted local community transmission in North Carolina, with about 64% of cases in unvaccinated individuals and 34% having received only one dose of the MMR vaccine.
MMR vaccination is now recommended for infants aged 6–11 months in high-risk areas.
Nationally, the U.S. saw 2,144 measles cases in 2025, the highest since elimination in 2000.
Measles is highly contagious and can lead to serious complications, including pneumonia and encephalitis. Fortunately, measles-related fatalities are seldom reported in the USA.
For the latest updates, visit the NCDHHS measles dashboard at dph.ncdhhs.gov or consult CDC resources on measles.
The Federative Republic of Brazil's iconic Carnival of 2026 will begin on February 13, drawing millions of locals and international visitors to cities like Rio de Janeiro, São Paulo, Salvador, and Recife.
As of January 22, 2026, Brazil is gearing up for this celebration, focusing on fun while prioritizing public health.
Local health authorities are urging caution due to concerns about mosquito-borne diseases, particularly the Zika virus, with over 24,000 suspected and 1,840 confirmed cases reported by Brazil's Ministry of Health by the end of December 2025.
Last year, many Zika cases were concentrated in the higher population states like São Paulo and Rio de Janeiro.
While Carnival's crowds and warm weather heighten exposure risks, simple precautions can help ensure a safe experience.
Currently, there are no vaccines for Zika available, and disease prevention relies on measures such as using insect repellent, wearing long clothing, and eliminating standing water.
Travelers, especially pregnant individuals, should consult healthcare providers and follow guidance from health authorities, such as the U.S. Centers for Disease Control and Prevention (CDC).
While the CDC has not issued a Travel Health Notice regarding Zika outbreaks in Brazil, it did confirm that an infected pregnant woman can spread it to her unborn baby, which may cause microcephaly.
In addition to Zika, the CDC has highlighted travel vaccinations for chikungunya and yellow fever when planning to visit Brazil in 2026.
The Republic of Colombia is currently experiencing a severe yellow fever outbreak, one of the worst in recent decades.
As of January 21, 2026, the Ministry of Health reported on Facebook that 157 confirmed cases had occurred since 2024, resulting in 70 deaths. This data represents a significant increase in transmission, particularly in the department of Tolima, which has recorded 137 cases and 55 deaths.
Historically considered low-risk for yellow fever, Tolima's situation indicates a shifting geographic distribution of the disease.
The recent rise in cases and a confirmed death in January 2026 reflect ongoing transmission.
Many cases arise in forested areas where Haemagogus mosquitoes and non-human primates transmit yellow fever. Still, some infections have occurred near urban areas, including the city of Bogotá, raising concerns for residents and travelers.
Bogotá is Colombia's largest city, with a population exceeding 7.5 million residents, and is a South American travel hub.
Colombia does not generally require proof of yellow fever vaccination for entry from most countries. A completed International Certificate of Vaccination or Prophylaxis (ICVP) is valid for life under International Health Regulations. It is required for travelers from certain parts of Africa or other South American countries, such as Brazil.
The single-dose yellow fever vaccine (YF-VAX, Stamaril) provides lifelong immunity for most people. It is a live attenuated vaccine, so it is not suitable for everyone.
When visiting Colombia in 2026, some domestic flights, national parks, or jungle tours may request vaccination proof, such as the ICVP.
Ebola disease was first identified in 1976. Since then, outbreaks have emerged periodically and infected people in several African countries
A vaccine that has already received approval and is stockpiled for use against the Zaire ebolavirus could become more affordable and easier to deploy in low-resource settings due to a new collaboration between CEPI and MSD.
With the support of up to $30 million in funding from CEPI, MSD, also known as Merck in the United States and Canada, will utilize Hilleman Laboratories—a joint venture between MSD and Wellcome—to develop the Ervebo® Ebola vaccine with an updated manufacturing process.
Furthermore, SK bioscience and IDT Biologika will collaborate to develop the updated drug-substance process and the associated drug product.
"In a single decade the world has transformed Ebola from a global emergency to a disease that can be stopped in its tracks – and now CEPI's support will help to enable a sustainable and accessible supply of MSD's Zaire ebolavirus vaccine for years to come at a more affordable price," explains Dr. Richard Hatchett, CEO of CEPI, in a press release on January 21, 2026.
"This deal brings together longstanding partners of CEPI with longstanding partners of MSD to boost global defences against one of the deadliest pathogens known to humankind, helping to save lives."
The existing MSD Zaire ebolavirus vaccine was developed in the midst of the 2014-16 West African Ebola crisis. Its manufacturing process is complex and potentially vulnerable to supply disruptions, making the vaccine expensive to produce and difficult to scale up. In addition, the vaccine must be stored in freezers at ultra-low temperatures of -70 degrees Celsius, creating substantial logistical challenges in the often remote, low-resource settings where Ebola outbreaks typically occur.
Currently, the Merck Ebola vaccine is not commercially available in the United States, but is maintained in the U.S. Strategic National Stockpile.
Florida health authorities have confirmed the first locally acquired case of chikungunya in 2026, occurring in Miami-Dade County.
This incident underscores the ongoing risks posed by this mosquito-borne virus, particularly given the significant number of travel-related cases.
For example, just a few days ago, thousands of travelers visited Miami-Dade to attend the NCAA football championship game.
As of January 17, 2026, the Florida Department of Health (DOH) reported 16 cases of chikungunya associated with travel. In the previous year, the state recorded 328 cases, with Miami-Dade County accounting for 214, significantly surpassing all other areas.
The vast majority (316) of Florida's travel-related cases originated from travelers returning from Cuba, where the virus has surged dramatically.
Cuba has reported more than 50,000 chikungunya cases in 2025, with all 15 provinces affected.
Nationally, the U.S. Centers for Disease Control and Prevention (CDC) has seen more than 400 chikungunya cases in 2025, with all but the two locally acquired instances linked to travel.
The CDC says the chikungunya virus, transmitted primarily by Aedes mosquitoes, causes symptoms in most infected individuals within 3–7 days of a bite. Common signs include high fever and severe joint pain, often debilitating. While the majority recover within a week, some experience persistent or chronic joint pain lasting months or even years.
As of January 21, 2026, there is no specific antiviral treatment for chikungunya.
However, a chikungunya vaccine has been approved by the U.S. FDA and is commercially available at travel clinics across the United States and in various other countries.
The CDC urges travelers to consult healthcare providers or travel medicine specialists before trips to affected destinations, use insect repellents, wear protective clothing, and eliminate standing water to reduce mosquito breeding.
Visitors to and residents in areas like South Florida should also maintain vigilance against local vectors, especially given the presence of competent Aedes mosquitoes.
Researchers at The University of Texas at El Paso (UTEP) have discovered unusually high levels of parasitic infection in the insects that transmit Chagas disease along the U.S.-Mexico border.
The kissing bugs were collected near homes and natural areas, raising concerns about the potential for local transmission of the disease in the Southwestern United States.
Led by Dr. Rosa Maldonado, a professor of biological sciences, the research team found that the infection prevalence in kissing bugs has significantly increased, from 63.3% in a study conducted in 2021 to 88.5% in the current study.
This alarming trend indicates that T. cruzi infections, which cause Chagas disease, are on the rise. It remains alongside dengue fever as one of the neglected diseases with the highest burden in the Americas.
"The infection prevalence in kissing bugs has risen significantly, indicating a marked upward trend for T. cruzi infections," Dr. Maldonado mentioned in a press release on January 6, 2026.
For this study, researchers collected kissing bugs from various locations, including El Paso County, Texas, and southern New Mexico, as well as from Franklin Mountains State Park, Central El Paso, and Canutillo.
The findings from this study suggest that Chagas disease is becoming an increasing public health issue in the Southwest. In this region, the disease was previously confined primarily to Latin America.
However, in 2025, Texas reported 22 human cases of Chagas disease, both imported and locally acquired.
Chagas disease is caused by the parasite Trypanosoma cruzi (T. cruzi) and is primarily spread by blood-feeding insects known as kissing bugs. This debilitating illness affects approximately 6 million people worldwide and can persist for decades in its chronic phase, often without symptoms.
However, it can lead to severe heart and gastrointestinal complications over time.
Previously, on March 20, 2025, researchers at UTEP successfully tested a faster, more sensitive, and more reliable method for diagnosing Chagas disease.
Furthermore, according to the World Health Organization, no approved vaccine exists to prevent Chagas disease. However, vaccine development is ongoing in 2026.
The current study, published in the journal Epidemiology & Infection, was conducted in collaboration with Dr. Priscila S. G. Farani, an assistant professor in UTEP's School of Pharmacy.
