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World Health Day

Today, the Centers for Disease Control and Prevention (CDC) joins the World Health Organization (WHO) and other public health partners in recognizing World Health Day, which this year spotlights vector-borne diseases.

Vector-borne diseases are bacteria, viruses, or parasites transmitted to people by mosquitoes, ticks, and fleas. These diseases are also frequently zoonoses, meaning they can be transmitted between animals and people. Malaria, lymphatic filariasis, dengue, and chikungunya are just a few examples of vector-borne diseases. The pathogens mosquitoes transmit sicken and kill millions of people each year. The tiny bloodsuckers, together with ticks and fleas, threaten people around the world with diseases that can be debilitating and sometimes fatal.

Vector-borne diseases like malaria and dengue threaten more than half the world’s population. Now, lesser known diseases like chikungunya and Zika are moving into new areas, posing an increasing threat to travelers and for introduction into the United States and other areas where they haven’t previously been found. The mosquitoes that spread these viruses have a huge geographic range, including in parts of the United States.  Though vector-borne diseases have the biggest impact on the world’s poorest people, everyone - rich and poor - is at risk for infections. Protect yourself whether abroad or at home:

  • Traveling?  Know your risk. Every year, millions of U.S. residents travel to countries where vector-borne diseases are spread. Many bring these diseases back into the United States. International travelers may face different vector-borne threats than are common in the United States. Learn about country specific risks and how to stay safe by visiting CDC’s Travelers’ Health website.   
  • Sick?  If you have a fever, rash, or other symptoms; see your doctor.
  • At home? Protect yourself and your family from insect and tick bites.  Use insect repellents when going outside. Wear protective clothing, including long sleeve shirts and pants. Shower shortly after coming indoors to remove any ticks crawling on you. 

To learn more about these diseases and what CDC does to prevent, treat and control them, please visit and

Contact Information

CDC Media Relations
(404) 639-3286


Tom Frieden, MD, MPH

Tom Frieden, MD, MPH


Photo: Dr Thomas Frieden

"Mosquito-borne diseases pose a threat to health security, with half the world’s population at risk. As we’ve seen recently with chikungunya, mosquitoes that cause these diseases are on the move and are threatening people in new places."

Tom Frieden, MD, MPH - Director of the Centers for Disease Control and Prevention

Lyle R. Petersen, MD, MPH

Lyle R. Petersen, MD, MPH


Photo: Lyle R. Petersen, MD, MPH

"Vector-borne diseases pose a unique challenge due to the complex interactions between the bugs that spread them, animals they feed on, humans and the natural environment. CDC is working hard to learn more about each of these factors and how they work together to spread disease so we can ultimately break the cycle of transmission and help prevent these infections."

Lyle R. Petersen, MD, MPH - Director, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)

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