The mosquito-borne Zika virus could be more dangerous than initially thought and has the potential to spread wider in the United States than originally projected, leading health officials in Ohio and other cold-weather states to issue new warnings and step up their mosquito control efforts as the summer months approach.
A new Centers for Disease Control and Prevention map shows the Aedes aegypti or Aedes albopictus mosquitoes that can carry the Zika virus can be found in 30 states, including Ohio, after originally identifying only Southern states as those most likely to face outbreaks.
Expanding the map has escalated concerns among medical professionals in Ohio and other states previously thought to be a low risk of Zika, which the U.S. Centers for Disease Control and Prevention recently confirmed causes microcephaly during pregnancy — a condition in which babies are born with very small heads and brain damage.
Zika’s symptoms, which include fever, rash and joint pain, are usually mild in adults, who often show no signs of the virus, and rarely get sick enough to go to the hospital.
But there is growing evidence to suggest Zika could be connected to an even broader set of complications for unborn fetuses as well as different kinds of infections of the brain and spinal cord that may be linked to adult neurological disorders.
A recent study out of Brazil — one of more than 30 countries for which the CDC has issued travel warnings because of widespread Zika outbreaks — has tied the virus to Guillain-Barré syndrome and acute disseminated encephalomyelitis (ADEM) — two serious autoimmune neurological conditions.
“Everyone should be paying attention to this,” said Dr. Bryan Ludwig, head of neurointerventional surgery for Dayton-based Premier Health. “While there’s clearly a tie to the Zika virus and the unborn fetus, it has yet to be determined what the exact tie is to the adult neurological system.
“The medial community is looking at unsubstantiated reports of increased numbers of people with Deion beret and acute disseminated encephalomyelitis, but we still don’t know if there is a connection. These things could be next on the horizon. Until we know, adults, in general, should be taking precautions to protect against mosquito bites.”
The growing threat has led the Obama administration to request about $1.9 billion in additional emergency funding to combat Zika in the U.S. In addition, President Obama signed bipartisan legislation last week that adds Zika to a list of diseases for which drug companies can collect incentives for developing vaccines or treatments — which currently do not exist for Zika.
Despite the potential public health threat, warnings about Zika have fallen on deaf ears among some pregnant women Miami Valley, many of whom were misinformed about the virus and how it is transmitted, or dismissed it as predominantly a problem in other countries.
“I have a vacation planned to Hilton Head (South Carolina) in June, and until I see something come out indicating that there are any cases originating in the U.S., I’m really not concerned about it,” said Melissa Hiti of Springboro. “Hopefully, I’m far enough along in my pregnancy that it wouldn’t have an effect anyway.”
The first case of Zika transmitted in the U.S. was in Texas. But that was a rare incident in which the virus was transmitted to a woman who had sex with a man who had recently returned from a trip to Venezuela, where he was infected.
While the virus can be spread through sexual contact, the virus is spread primarily from infected mosquitoes to people.
As of Tuesday, the CDC said there were 358 cases of the Zika virus identified in the continental United States. Most in the U.S. were infected while traveling abroad in areas where the virus is spreading, particularly the Caribbean and Central and South America.
There have been nine confirmed cases of Zika virus in Ohio, including a 56-year-old Butler County woman returning from Guyana. All were contracted outside of Ohio during travel.
“The cases that we have seen have all been in travelers who have returned from countries where there is ongoing Zika virus transmission in the mosquitoes that are there,” said Dr. Mary DiOrio, the state health department’s medical director. “Right now, the risk for individuals in Ohio is if they’re going to be traveling to a country that has ongoing Zika virus transmission.”
Warm weather coming
Even after the mosquito season hits next month, the presence of mosquitoes does not necessarily mean they will be carrying Zika when the weather warms, DiOrio stressed.
“There is a whole process that would have to occur before a mosquito in Ohio would be able to spread the Zika virus,” she said, noting that a mosquito that bites an infected person would have to live long enough for the virus to replicate to the point where it could be transferred to another person.
The average mosquito lives about six to eight weeks under ideal conditions, and many live less than a week.
Despite the slim chance of an outbreak in Ohio, the state health department is working with its local counterparts to step up their efforts to control local mosquito populations that could spread Zika.
“We’re making plans here in Ohio for when mosquito season starts to make sure that we’re going to be appropriately able to monitor the mosquitoes in the area,” DiOrio said.
That’s going to require some re-calibration to the state’s current mosquito control measures, which are designed primarily to detect the mosquitoes that carry West Nile and other more common viruses, said Richard Gary, a state entomologist who attended a one-day Zika Action Plan Summit held by the CDC earlier this month.
Of the two mosquito species known to carry Zika, the Aedes albopictus mosquito, or Tiger mosquito, is the one people in Ohio are most likely to encounter, Gary said. However, it’s also the most difficult to trap and keep under surveillance.
“We are considering making some changes both to surveillance as well as control,” according to Gary, who said one reason the Tiger mosquito is difficult to trap is because it does not readily come to the traps they use for West Nile mosquitoes. “One of the things we are doing is that we have purchased a trap that is suppose to be a little bit better at detecting this mosquito, and we’re hoping to distribute them to our local health departments.”
Beginning next month, area counties will initiate its usual mosquito control measures and begin trapping adult mosquitoes and conducting larvae surveillance.
In addition to employing new traps, this year’s plan may include new and more aggressive strategies to address the Zika virus, including spraying insecticides during the day and spraying indoors, which are being considered by the state health department.
“These mosquitoes are more active during the day than the West Nile mosquito we spray for at night, and they tend to take shelter indoors,” Gary said. “We will definitely be stepping up our mosquito surveillance, but how we will address specific Zika issues will depend on the guidance we get from state department of health.
“Zika is a new emerging illness that we need to address in an open-minded way,” he said. “We need to be open to changes in how we address the risk to the public.”
Even if the virus is transmitted in Ohio, a quick response can reduce its impact.
That’s why the state health department has begun doing its own testing for the Zika virus at its Reynoldsburg lab.
Although blood samples will still be sent to the Centers for Disease Control and Prevention for confirmation, by testing in state, the health department will know within 48 hours if there is danger of a pandemic and can take action quickly, instead of waiting weeks for results from the CDC.
“I believe we have good human surveillance measures right now, so we shouldn’t have to worry about missing potential cases,” DiOrio said.