reaches epidemic proportions affecting large numbers of people in a short time It must cross national boundaries and threaten populations meaning entire groups of people such WARNING In 2007 the World Health Organization WHO created a warning called the public health emergency of international concern This warning is used when an epidemic crosses international boundaries and threatens populations worldwide Between 2007 and 2016 only four health crises have received this designation The first occurred in 2009 during a global influenza epidemic In 2014 the WHO used the designation twice first for a polio epidemic and later to combat the global Ebola crisis The fourth time in 2016 was for the Zika virus as pregnant women and their children Solutions to this kind of an emergency can be found fastest when organizations pool their resources and work together By declaring a public health emergency the WHO would be able to coordinate research on this virus particularly regarding its effect on pregnant women The organization encouraged governments and nonprofit groups to help fund this research and begin the process of developing a vaccine against Zika PREVIOUS PATTERNS Scientists and doctors were not certain what the eventual impact of the Zika virus would be but they knew it would
Pregnant women in Brazil Colombia and other South American nations found themselves at the center of international attention during the Zika outbreak likely continue spreading They believed it might follow the pattern of a related virus called chikungunya This virus was first described in 1952 in Tanzania a country on the east coast of Africa After this outbreak researchers found chikungunya throughout Africa and Asia but the number of people infected remained low Then in 1999 and 2000
a larger outbreak took place in Africa's Democratic Republic of the Congo In 2004 outbreaks occurred in two villages in Kenya Up to 75 percent of the people in the village contracted the virus CHIKUNGUNYA As with the Zika virus chikungunya is typically transmitted by a mosquito bite Most people who are infected with the virus show symptoms The first symptom is often a rapid rise in body temperature The second is joint pain Many viruses cause aches and pains but the joint pain in chikungunya is so severe patients often cannot stand up They cannot even shake someone's hand because it is too painful Although most patients recover fully and feel better in a week in some cases the joint pain can linger for months Fortunately once a patient recovers from chikungunya he or she is immune for life In past outbreaks approximately one in 1 000 cases has been fatal In December 2013 two cases of chikungunya were reported on Saint Martin an island in the Caribbean Sea These cases marked the first reports of local transmission in the Americas Before this travelers had returned to the Americas already sick from the virus This was the first time someone had actually gotten the virus after being bitten by a mosquito in the Americas From those two cases the numbers of countries and people affected has continually grown By April 2015 approximately 1 7 million suspected cases of chikungunya had been reported in 43 nations in North and South America Chikungunya
is an amazing virus says Ann Powers a virologist with the US Centers for Disease Control and Prevention CDC It spreads incredibly fast and is very aggressive In some communities more than half EPIDEMICS AND ENDEMIC DISEASES the population gets sick 10 One of the nations in which chikungunya has found a home is the United States where it has spread in Florida Researchers Brazil's Minister of Health Marcelo Castro warned the Zika virus might be more than a passing epidemic Castro says the Zika virus might represent an endemic disease meaning it has become a permanent part of the Brazilian ecosystem and will never be driven out completely Other mosquito carried viruses that have already become endemic in the Americas include West Nile virus yellow fever dengue and chikungunya believe the Zika virus may follow its lead Zika is closely related to the chikungunya virus and the same mosquito spreads it As people around the world began worrying about the possible extent and severity of a widespread Zika outbreak scientists worked to better understand the virus and its effects
