Bumpy rash, achy joints, inflamed eyes? Almost 24,000 infant have been infected by Zika Virus.
There’s a new disease in townNever heard of the Zika virus? That may change soon. Almost unknown in humans until the past decade, Zika is now spreading fast through South America and Oceania, and it may soon knock on our doors, too. Although it can resemble a mild case of the flu, the disease can lead to some serious neurological complications, including paralysis and difficulty breathing. It’s also the first known mosquito-borne disease that can be transmitted sexually among humans.
The virus was discovered in 1947 in a feverish rhesus monkey living in the Zika Forest of Uganda, but until 2007 scientists knew of only 14 human cases of the disease. That year it arrived on the travel-brochure-perfect Yap Island in the southwestern Pacific Ocean. Within a few months, nearly three-quarters of the island’s 11,000 or so residents older than 3 had been infected.
At first, those sick with Zika developed fever, joint pains and eye inflammation; then a red, bumplike rash erupted, sometimes followed by painful swelling of hands and feet. Some people vomited. Others were sensitive to light. But the symptoms usually resolved a couple of days later, and no one died.
In 2013 Zika popped up again, this time in Tahiti and other parts of French Polynesia. An estimated 28,000 people (about 11 percent of the population of those islands) felt sick enough with the virus to seek medical care. By 2014 it was showing up in several other South Pacific spots: New Caledonia, east of Australia; the Cook Islands; and, early this year, Easter Island, which marked the official arrival of the disease in the Americas, since that remote island is part of Chile.
Zika showed up in Brazil in May, prompting the World Health Organization and the Pan American Health Organization to issue an epidemiological alert. As of June 16, the number of suspected cases in the Brazilian state of Bahia topped 24,000.
So what happened? Why would an obscure virus emerge so suddenly and spread so fast?
Zika is a flavivirus related to yellow fever, chikungunya, dengue fever, West Nile and Japanese encephalitis, all of which are common in tropical climates but have started to spread in the United States and Europe in concert with warming temperatures, and they can cause serious health problems, even death.One possibility is that the virus has evolved, either making humans more susceptible or making it easier for mosquitoes to transmit it. “These types of viruses can evolve very fast,” Freire says. “The problem [with confirming that theory] is that we have very few complete genomes of this virus to study.”
Researchers believe that Zika most likely was spread in the blood of an infected traveler — perhaps someone from Uganda or elsewhere in East Africa — who served as a meal for a local mosquito. When that insect latched on to someone else, a new chain of transmission began.
The virus spread quickly because people in the new location had no previous exposure or immunity. “When a new virus is introduced in a population which has never seen it before, it can be transmitted easily, explosion-like,”Therefore, Zika virus will likely spread to new areas, and people should take steps to prevent mosquito bites to reduce their risk of infection.”
There’s a new disease in townNever heard of the Zika virus? That may change soon. Almost unknown in humans until the past decade, Zika is now spreading fast through South America and Oceania, and it may soon knock on our doors, too. Although it can resemble a mild case of the flu, the disease can lead to some serious neurological complications, including paralysis and difficulty breathing. It’s also the first known mosquito-borne disease that can be transmitted sexually among humans.
The virus was discovered in 1947 in a feverish rhesus monkey living in the Zika Forest of Uganda, but until 2007 scientists knew of only 14 human cases of the disease. That year it arrived on the travel-brochure-perfect Yap Island in the southwestern Pacific Ocean. Within a few months, nearly three-quarters of the island’s 11,000 or so residents older than 3 had been infected.
At first, those sick with Zika developed fever, joint pains and eye inflammation; then a red, bumplike rash erupted, sometimes followed by painful swelling of hands and feet. Some people vomited. Others were sensitive to light. But the symptoms usually resolved a couple of days later, and no one died.
In 2013 Zika popped up again, this time in Tahiti and other parts of French Polynesia. An estimated 28,000 people (about 11 percent of the population of those islands) felt sick enough with the virus to seek medical care. By 2014 it was showing up in several other South Pacific spots: New Caledonia, east of Australia; the Cook Islands; and, early this year, Easter Island, which marked the official arrival of the disease in the Americas, since that remote island is part of Chile.
Zika showed up in Brazil in May, prompting the World Health Organization and the Pan American Health Organization to issue an epidemiological alert. As of June 16, the number of suspected cases in the Brazilian state of Bahia topped 24,000.
So what happened? Why would an obscure virus emerge so suddenly and spread so fast?
Zika is a flavivirus related to yellow fever, chikungunya, dengue fever, West Nile and Japanese encephalitis, all of which are common in tropical climates but have started to spread in the United States and Europe in concert with warming temperatures, and they can cause serious health problems, even death.One possibility is that the virus has evolved, either making humans more susceptible or making it easier for mosquitoes to transmit it. “These types of viruses can evolve very fast,” Freire says. “The problem [with confirming that theory] is that we have very few complete genomes of this virus to study.”
Researchers believe that Zika most likely was spread in the blood of an infected traveler — perhaps someone from Uganda or elsewhere in East Africa — who served as a meal for a local mosquito. When that insect latched on to someone else, a new chain of transmission began.
The virus spread quickly because people in the new location had no previous exposure or immunity. “When a new virus is introduced in a population which has never seen it before, it can be transmitted easily, explosion-like,”Therefore, Zika virus will likely spread to new areas, and people should take steps to prevent mosquito bites to reduce their risk of infection.”
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