Emerging Infections and Disease Outbreaks

Childhood Infections

A child with Dengue fever during a 2002 outbreak in Honduras
A child with Dengue fever during a 2002 outbreak in Honduras. Photo by Getty Images

While pediatricians often focus on common childhood infections, such as croup, flu, and RSV, it is also important to be aware of some of the less common emerging infections that are out there.

Especially with as easy as it is travel almost anywhere in the world these days, it is important to remember that these infections are often just a plane ride away.

Emerging Infectious Diseases

These are the latest emerging infectious diseases that you have likely been hearing about in the news (if you have been paying attention):

  • MERS-CoV - a severe acute respiratory illness, people with Middle East Respiratory Syndrome (MERS) caused by this new or novel coronavirus (CoV) typically have a fever, cough, and difficulty breathing. At least 10 countries (most in or around the Arabian Peninsula) have had cases of lab-confirmed MERS-CoV since the illness was first discovered in Saudi Arabia in 2012. There are no specific treatments for this illness and half of the people who have developed MERS-CoV have died. It is thought that indirect exposure to infected camels may be to blame for recent MERS-CoV outbreaks, although most people get infected from other people and have no known, direct exposure to camels.
  • Ebola - Ebola or Ebola hemorrhagic fever is caused by direct contact with blood or body fluids of a person or animal who is infected with the Ebola virus. Symptoms can include the sudden onset of fever, headache, joint and muscle aches, sore throat, weakness, diarrhea, vomiting, and stomach pain. Other symptoms can include a skin rash, red eyes, and internal and external bleeding. The CDC states that "Ebola poses little risk to the U.S. general population." The two Americans who contracted Ebola are healthcare workers who were living in Monrovia, Liberia.
  • Zika fever - endemic in Africa, Asia, infections with the Zika virus have recently been spreading to islands in the Western Pacific. A relatively mild infection, Zika fever is transmitted by mosquitoes. Symptoms of Zika fever can last up to 4 to 7 days and may include fever, headache, joint pains, muscle aches, rash, and red eyes.
  • Chikungunya virus - more typically found in Africa, Asia, Europe, and the Indian and Pacific Oceans, this mosquito-borne viral disease has been found in some Caribbean islands since 2013. Symptoms of Chikungunya can include high fever, rash, severe joint pain (arthralgia), and arthritis, and often last for about 7 to 10 days. Chikungunya can rarely lead to serious complications, including myocarditis and Guillain-Barré syndrome and joint symptoms can sometimes relapse or become persistent for months to years.
  • Dengue - Dengue is probably the most common infection that you have never heard of. Up to 100 million people around the world are infected with dengue viruses each year, although it is rare in the continental United States. A mosquito-borne illness, infected people can develop symptoms of dengue fever (high fever, severe headache, muscle and joint pains, and a rash, etc.) or dengue hemorrhagic fever, a more severe, life-threatening disease. About 22,000 people die from dengue each year, mostly children.
  • H7N9 - H7N9 is a new form of avian influenza A that was first discovered in China in March 2013. It originally caused at least 132 cases and 44 deaths and had seemed to stop until a second wave began in October 2013.
  • H5N1 - H5N1 or highly pathogenic avian influenza (HPAI) A (H5N1) was first discovered in 2003. It has since caused at least 664 infections (and at least 391 deaths) in 15 countries - mostly in Asia, Africa, the Pacific, Europe and the Near East.
  • Nodding Syndrome - a condition that is possibly connected to onchocerciasis (River Blindness) and which causes children to have an atonic seizure, with episodes during which they repetitively nod their head and have other seizure-like activity. Nodding Syndrome is also associated with neurologic and cognitive impairment, growth problems, and delayed puberty.
  • Hendra virus infection - a viral infection that is transmitted from fruit bats (flying foxes) to horses, who can then get people sick, causing sometimes fatal, flu-like symptoms.
  • Enterovirus 71 - since it was first discovered in California in 1969, enterovirus 71 or EV71 has caused periodic minor and major outbreaks all over the world.

It is important to remember that few of us will ever encounter one of these emerging infectious diseases.

So why is it important to know about them?

It isn't, as some people might think, just to get people scared.

If we aren't aware of these emerging infectious diseases, then we might miss the next one that causes a deadly global pandemic. After all, some of the "deadliest pandemics in recorded human history" were caused by emerging infectious diseases, including:

  • the Black Death Pandemic (bubonic plague)
  • the 1918 flu pandemic
  • the HIV/AIDS pandemic

Even West Nile started as an emerging infectious disease. We have a long way to go before we can identify and then simply cure an emerging infectious disease, but you can't do much of anything if you don't even know when these infections emerge.

Emerging Infectious Disease Outbreaks

Where are the latest emerging infectious disease outbreaks?

  • MERS-CoV - there have been at least 721 cases of MERS-CoV and 298 deaths, with most of the cases in Jordan, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates (UAE). Secondary, imported cases have also been reported in France, Germany, Italy and the United Kingdom (UK), in Europe; and Tunisia, in North Africa.
  • Ebola - Most cases of Ebola occur in Democratic Republic of the Congo (DRC), Gabon, South Sudan, Ivory Coast, Uganda, Republic of the Congo (ROC). There are currently outbreaks of Ebola in Guinea, Liberia, and Sierra Leone, with at least 1201 cases and 672 deaths.
  • Zika fever - Zika fever was first detected outside Asia and Africa in 2007, in an outbreak on Yap Island in the southwestern Pacific Ocean. There are currently outbreaks of Zika fever in the Cook Islands, Easter Island, New Caledonia, and French Polynesia (Tahiti).
  • Chikungunya - there have recently been outbreaks of chikungunya in many Caribbean countries, leading the CDC to recommend that travelers protect themselves from mosquitoes. These countries include many Caribbean countries, from Anguilla and Antigua to the US Virgin Islands. The Chikungunya virus has now hit the mainland United States now, with the first reported case in Florida in July 2014.
  • Dengue - Dengue viral infections are endemic in at least 100 countries in Asia, the Pacific, the Americas, Africa, and the Caribbean. Most of the cases in the continental United States are in travelers, but there have been outbreaks in south Texas (2005) and Hawaii (2001), and dengue is endemic in Puerto Rico, the U.S. Virgin Islands, Samoa, and Guam.
  • H7N9 - this new flu virus strain has led to at least 350 cases of avian influenza A (H7N9) and 100 deaths in China.
  • H5N1 - the latest cases if H5N1 infections include 4 children in Cambodia, 3 of whom died, and 2 people in Egypt, including a 4-year-old. Most had recent contact with dead or sick poultry.
  • Nodding Syndrome - there have been outbreaks of Nodding Syndrome in the United Republic of Tanzania, Uganda, and South Sudan.
  • Hendra virus infection - there have been a limited number of outbreaks of Hendra virus infections along the east coast of Australia since 2008.

If you are traveling out of the United States, in addition to making sure your vaccines are up-to-date, you certainly want to be aware of these emerging infectious. For the rest of us, being aware of these emerging infectious diseases can simply make it easier to understand what is going on in the world and to help make sure that we don't miss the next global pandemic.

Still, we shouldn't forget about the outbreaks of vaccine-preventable diseases that unfortunately are still occurring in the United States and around the world. Emerging infections aren't the only thing to think about when we still have measles outbreaks so long after the endemic spread of measles was stopped.


Dowell, Scott F. Nodding Sydrome. Emerging Infectious Disease Journal. Volume 19, Number 9—September 2013.

Hayes, Edward B. Zika Virus Outside Africa. Emerging Infectious Disease Journal. Volume 15, Number 9—September 2009

Morens DM, Fauci AS (2013) Emerging Infectious Diseases: Threats to Human Health and Global Stability. PLoS Pathog 9(7): e1003467.

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