Honest about the risks, and specific about what prevents each one.
Dengue
Mosquito-borne and present, including in resort areas. The mosquito that carries it bites during the day, which catches people out — repellent is a morning habit as much as an evening one.
Prevention No vaccine is available in Canada. Repellent, long sleeves at dusk and dawn, air conditioning or screens.
Zika
Present. Matters most if you are pregnant or planning to be.
Prevention Bite avoidance. Worth a conversation before booking if pregnancy is on the horizon.
Food and water
The reason the first two vaccines on this page are the first two. CDC also lists multidrug-resistant Salmonella Newport among the foodborne risks in Mexico. Street food is much of why people go, and we are not going to tell you to avoid it — vaccination exists so it does not have to be a gamble.
Prevention Bottled or treated water, ice from safe water, hot food served hot, peel your own fruit.
Altitude
Mexico City is at 2,240 m; parts of the country go considerably higher. The Government of Canada notes high-altitude illnesses can be life-threatening and may require immediate medical evacuation.
Prevention Ascend gradually, rest the first day, drink more water than feels necessary, and go easy on alcohol. Tell us if you have heart or lung conditions.
Chagas disease and leishmaniasis
Both insect-borne and both on CDC’s list for Mexico — Chagas from triatomine bugs, leishmaniasis from sand flies. Rural and mostly relevant to people sleeping in older rural housing rather than hotels.
Prevention Bite avoidance, and a bed net if you are staying somewhere rural without screens.
Leptospirosis, melioidosis, hantavirus and tuberculosis
All appear on CDC’s risk list for Mexico. None changes what a typical holiday needs, but the whole list belongs on the page rather than the convenient half of it.
Prevention Avoid floodwater and contact with soil or muddy water; avoid rodents; avoid people who are unwell.