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The Current Buzz on Travel Health: The Shifting Landscape of Vector-Borne Disease

September 15, 2025

In the post-COVID era, travel is regaining momentum, but so are the associated health risks. For travel health professionals, the pre-travel consultation has always been about more than just vaccine recommendations, but now more than ever, high-quality care means navigating a dynamic global health environment altered by climate change and evolving travel habits.

Pharmacy professionals are well positioned to identify patients who may not have received health advice prior to travel, and to help patients access the information, care and products they need to stay healthy while travelling. This is especially true when it comes to vector-borne diseases (VBDs), which are transmitted by mosquitoes, ticks, and other insects; epidemiology is constantly evolving, and updated knowledge is essential to fully educate and protect patients.

Warming World, Moving Vectors

The connection between climate change and VBDs is well documented. The World Health Organization (WHO) estimates that over 80% of the global population is at risk of VBDs, with over 700,000 annual deaths attributed to diseases transmitted by insects. Surveillance organizations are observing annual increases in incidence, as well as associated morbidity and mortality, and these numbers are likely to continue rising due to factors impacted by travel patterns, climate change, deforestation, and urbanization.

 Key drivers:

Increased temperatures accelerate the pathogen development cycle within vectors (e.g., mosquitoes), enabling them to become (and remain) in infectious states more quickly.

Changes to regional precipitation patterns – both increased rainfall/flooding, as well as drought, can increase mosquito breeding. Floodwaters create standing pools that are ideal for Anopheles mosquitoes (malaria); drought conditions may prompt water storage in containers, favouring Aedes breeding (dengue, chikungunya, zika, yellow fever).
Changes to climate and seasonality, such as warmer winters, allow mosquitoes and ticks to survive at higher latitudes and altitudes, expanding into areas that were once considered “safe.” The United Nations Development Programme confirms that Aedes species’ ranges are expanding, bringing dengue, Zika, and chikungunya to previously unaffected regions

New Travel Patterns, Novel Risks

Choice of Destination: Many people are now choosing nature-based trips such as safaris, forest hikes, and rural stays, which may be perceived as “safer” than crowded urban centers. This shift puts this patient group at a higher risk for VBDs that are commonly transmitted in rural or remote areas. Meanwhile, rapid urbanization, population growth, and deteriorating vector control increase the risk of diseases transmitted by Aedes mosquitoes, especially in low- and middle-income countries.

Visiting Friends and Relatives (VFR): This group of travellers tends to stay in endemic areas longer, visit rural or non-tourist regions, and may perceive their trip as low risk because they are “returning home.” As a result, many individuals may not seek pre-travel advice and may lack immunity to circulating local strains. Pharmacists can enhance outreach to this group through targeted messaging within the community, pharmacy signage, and social media prompts.

Vector-Borne Diseases: Quick Updates

Dengue Fever

Epidemiology: The WHO approximates that approximately half of the global population is at risk of dengue fever, with an estimated 400 million infections in over 100 countries annually.

Prevention is Paramount: Emphasize the consistent use of effective repellents (such as DEET and icaridin), wearing long clothing, and using permethrin-treated bed nets. Educate patients on the daytime biting habits of Aedes aegypti, as patients often are unaware of the differences in peak activity times for different species of mosquitoes.

Vaccination: While a live-attenuated vaccine, Qdenga® (TAK-003), is approved in some markets for individuals aged 4 years and older, it is not yet available in Canada.

Chikungunya

Epidemiology: Chikungunya virus (CHIKV), transmitted by Aedes aegypti and Aedes albopictus, causes outbreaks in Africa, Asia, the Americas, and the Caribbean. The disease is characterized by acute fever and joint pain, which may progress to chronic chikungunya arthritis in 40% of people who contract the disease.

Prevention: Like dengue, preventing mosquito bites is essential, especially during daylight hours when Aedes mosquitoes are most active. As listed above, DEET, icaridin, and permethrin-treated clothing are all effective in preventing bites from Aedes mosquitoes.

Vaccination: Health Canada approved the live-attenuated IXCHIQ® vaccine in June 2024 for adults 18-64 years travelling to or living in areas with ongoing CHIKV transmission. Due to reports of serious adverse events (neurological, cardiac) in those aged ≥65 years, the Committee to Advise on Tropical Medicine and Travel (CATMAT) recommends against use in this age group until further data is available. *As of the writing of this post, the chikungunya vaccine is not listed in Schedule 3 of O. Reg. 256/24 of the Pharmacy Act, meaning that a medical directive or direct order would be required for a pharmacy professional to administer the chikungunya vaccine. 

Additionally, a non-live, virus-like particle vaccine VIMKUNYA® (CHICKV VLP), approved in some markets for use in patients 12 years old and older, is currently under review by Health Canada.

Zika Virus

Epidemiology: Zika virus circulates in parts of the Americas, Asia, Africa, and the Pacific. While typically mild or asymptomatic, Zika infection during pregnancy can cause congenital Zika syndrome, including microcephaly.

Prevention: No vaccine exists. Zika prevention strategies are identical to those for dengue and chikungunya, with an emphasis on preventing mosquito bites.

Clinical Pearls: CATMAT no longer routinely recommends that travellers who are pregnant or planning to become pregnant avoid travel to Zika-endemic areas and similarly no longer recommends measures to prevent sexual transmission from asymptomatic travellers to Zika-affected regions.

Malaria

Burden: The WHO’s World Malaria Report (2024) recorded 263 million cases and 597,000 deaths in 2023.

Pharmacist’s role: Select chemoprophylaxis based on resistance patterns, patient health status, and trip duration, seeking updated guidance on malaria epidemiology from current, trusted sources.

Adherence tip: Counsel on pre- and post-travel dosing requirements to ensure full prophylactic coverage.

Tick-Borne Diseases

Ontario context: The expansion of Ixodes habitats and a greater proportion of the year with temperatures above freezing have increased the risk of Lyme disease in many areas of the province.

Counselling points: Wear long-sleeved clothing, tuck pants into socks, use DEET or icaridin repellents, perform daily tick checks, and remove ticks promptly with fine-tipped tweezers.

Minor Ailment Opportunity: Ontario pharmacists may prescribe post-exposure prophylaxis as part of the minor ailments scope of practice.

Beyond the Bite: Bed Bugs as Stowaways

While not specifically a vector-disease risk, bed bugs bites (Cimex lectularius) can cause itching, distress, and secondary infections. Travellers may inadvertently bring bed bugs back from their travels if there is an infestation in their travel destination.

Pharmacist tips for travellers:

Inspect before unpacking – use a flashlight to check mattresses, headboards, and drawers for stains or live bugs.
Smart luggage strategies include using hard-sided bags, keeping bags off beds, sofas and carpeted areas at the destination, and unpacking at home in non-carpeted areas like garages.
Heat treatment – Upon return, launder and dry clothing (including unworn items) on high heat for at least 30 minutes to eliminate live bugs and eggs.

 The “New Normal”: Travel Health Edition

Just as the world around us is becoming more complex, the landscape of travel health is also evolving. While travel health clinicians will celebrate the addition of new tools to our preventative health toolboxes (such as new antigens for diseases like chikungunya), new risks associated with climate change and evolving travel preferences pose risks that must be addressed with up-to-date information. By staying informed through trusted sources and coupling preventive strategies with tailored patient education, pharmacists can ensure that modern travel adventures result in a safe return, without the unintended souvenirs of vector-borne disease.