On the rise in The Caribbean and Central and South America.
Effects Fever, headache, and joint and muscle pains; can be fatal if untreated.
What to do Dengue is spread by mosquito bite, so the best defense is long pants, socks, and a long-sleeved shirt, and using lots of insect repellent with deet.
On the rise in Australia, with a concentration around Sydney.
Effects Similar to a bad cold and fever, accompanied by a severe cough with a whooping sound.
What to do Keep up to date with your immunizations. A highly contagious respiratory infection, pertussis is spread through coughing or sneezing.
HAND, FOOT, AND MOUTH DISEASE
On the rise in Asia, especially China.
Effects Fever, skin rash with blisters, sores in the mouth.
What to do There's no vaccine for HFMD, which mainly affects children under 10. It's spread by contact with unwashed hands or contaminated surfaces, so don't share eating utensils and make sure to wash up often.
On the rise in Parts of Asia, including India and Thailand.
Effects Fever, chills, vomiting, headache, and joint pain.
What to do Like malaria and dengue, chikungunya is spread by mosquito bite, so use an insect repellent with deet. If you're also using sunscreen, apply it first; the bug spray will be more effective.
On the rise in Bali, particularly near the airport in Denpasar.
Effects A coma and death are likely. The vaccine alone may cause nausea, vomiting, headache, and dizziness.
What to do Keep your distance from animals—dogs, cats, monkeys, and mongooses, all of which can spread rabies through their bites. If you're bitten, wash the wound immediately with soap and water and find out about the animal's vaccination history, if possible. See a doctor and follow the recommendations, which may include a series of vaccinations.
Source: Centers for Disease Control and Prevention