Five things you need to know about Zika
FIRST IN AFRICA
Aedes aegypti is a small, dark, hot-weather mosquito with white markings and banded legs. Scientists believe the species originated in Africa, but came to the Americas on slave ships. It’s continued to spread through shipping and airplanes. Now it’s found through much of the world, including the southern United States.
ONCE YELLOW FEVER MOSQUITO
Early in the 20th century, scientists showed it was the engine behind devastating yellow fever outbreaks. It became known as the yellow fever mosquito, although that name has been used less often since a successful vaccine was developed against yellow fever. Since then, it’s also been identified as a carrier for other tropical illnesses such as dengue fever, chikungunya and Zika fever. Scientists are investigating whether other types of mosquitoes are spreading Zika in Latin America and the Caribbean, too.
A CITY DWELLER
Aedes aegypti is the primary spreader of Zika and some other tropical diseases, largely because of its unusually cozy relationship with people. While other species thrive in more rural areas, or at least in parks and gardens, this is a domesticated species — sort of a housecat mosquito — accustomed to living in apartment buildings and city centers. It prefers biting people to animals and likes to feed indoors, during daylight hours. Also, it is a hardy bug that can be particularly challenging to get rid of.
KILLED OFF, IT CAME BACK
In the early 20th century, many countries developed programs to destroy all Aedes aegypti mosquitoes through spraying chemicals and other measures. By 1970, it was eradicated from much of South America — including Brazil. But many mosquito-control programs were cut back. Reasons included budget cuts, and concerns about the use of some insecticides, and the yellow fever vaccine made the mosquito’s elimination less critical.
The species roared back. It played a key role in the reemergence of dengue fever in Latin America and the Caribbean, and the recent spread of chikungunya and Zika virus.
GOING FOR BLOOD
Female mosquitoes drink human blood for nutrients used in making eggs. After a female bites an infected person, it can spread the virus through its saliva to its next human victim. Some scientists think Zika may have arrived in Brazil in 2014, carried by visitors attending World Cup soccer games. Perhaps one or more infected visitors were bitten by mosquitoes and started the chain reaction, said Jeffrey Powell, a Yale University mosquito expert who works in Brazil.
Only one locally transmitted Zika case has been reported in the United States, but cases among travelers returning to or visiting Ohio and other states are likely to increase as outbreaks continue to spread across Latin America and into Africa, health official warn.
Authorities have confirmed more than 30 cases of the mosquito-borne Zika virus in the U.S. — all but one imported from other countries.
On Tuesday, the first known case of Zika virus transmission in the U.S. was reported in Texas by local health officials, who said it was contracted through sexual contact. The case was reported a day after the World Health Organization declared Zika an international public health emergency.
Still, the domestic threat is minimal in the dead of winter when mosquitoes lie dormant, and, so far, no imported or locally transmitted cases of Zika have been identified in Ohio.
“It is always important to protect against mosquito bites and to prevent diseases transmitted by mosquitoes, but currently there is limited reason for Ohioans to be concerned about the Zika virus,” reads a news release from the Ohio Department of Health, which is preparing an update on Zika for today.
Still, as a precaution, ODH is following Centers for Disease Control and Prevention guidelines and advising pregnant women and others not to travel to more than two dozen countries battling outbreaks of the Zika virus, which has been linked to a rare neurological condition known as microcephaly.
Microcephaly is a condition in which children are born with unusually small heads that may lead to developmental and intellectual disabilities.
“People traveling to areas with Zika virus transmission should take precautions to prevent mosquito bites…because of the possible association between Zika virus infections in pregnant women and certain birth defects,” ODH stated.
Most people, one in five, who contract the Zika virus don’t show symptoms. Others may suffer symptoms such as fever, joint pains, eye inflammation, rashes and painful swelling of hands and feet. But the symptoms usually resolve in a couple of days, and the disease is rarely fatal.
However, some babies born with microcephaly have died as a result of miscarriage or shortly after birth in some parts of the world where Zika outbreaks are widespread.
The most recent epidemic was first identified last May in Brazil and has since spread to several other countries and territories. Zika outbreaks have previously occurred in areas of Africa, Southeast Asia, and the Pacific Islands, according to the CDC.
There is no treatment or vaccine for the virus, but drugmaker Sanofi Pasteur said Tuesday it is launching an effort to research and develop a vaccine to prevent Zika after the World Health Organization declared a global emergency over its explosive spread across the Americas.
Zika falls into the same family of viruses as dengue fever, and Sanofi made the first dengue vaccine shot, which was licensed last year in Brazil after years of scientific struggle to develop one.
Sanofi’s Dr. Nicholas Jackson, who is leading the company’s Zika effort, said it will leverage experience with the dengue vaccine, yellow fever and Japanese encephalitis. It hopes existing manufacturing capabilities, technology and ongoing studies in 10 countries on the dengue virus will also help speed up the search.
Vaccine development typically takes years. Jackson, head of global research for Sanofi Pasteur, said the company wants to “greatly accelerate” the hunt for a vaccine but that Brazilian predictions of a version within three to five years sound “ambitious.”
The Associated Press contributed to this story.
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