Three more cases of the Zika virus have been confirmed in Harris County, according to Health Department officials. These cases bring the total number of patients in Harris County who contracted the virus to four.
Three other cases are confirmed in the city of Houston, bringing the total number of cases in the Houston metropolitan area to seven.
Harris County Public Health & Environmental Services said Monday that the three new patients had all recently traveled to Latin America. All four of the patients in the county cases have since recovered.
The latest city of Houston case is a female patient between 40 and 45 years old. She traveled to Honduras in December and returned to the Houston area. She recently started feeling ill.
The news comes the same day that the World Health Organization declared the spread of Zika an international emergency.
WHO estimates there could be up to 4 million cases of Zika in the Americas in the next year, but no recommendations were made to restrict travel or trade.
"It is important to understand, there are several measures pregnant women can take," WHO Director-General Margaret Chan said. "If you can delay travel and it does not affect your other family commitments, it is something they can consider.
"If they need to travel, they can get advice from their physician and take personal protective measures, like wearing long sleeves and shirts and pants and use mosquito repellent."'
On Friday, health officials confirmed that a man traveled to Honduras in December and tested positive for the virus. The man was between 35 and 39 years old. His condition is not known.
"The only risk factor we have right now for Zika is foreign travel to where it is an epidemic,” said Kathy Barton, the spokesperson for the Houston Health Department. “For most of us, that is Central and South America. We don't have any local transmission going on here. Although at some point we could. But it's not happening yet.”
KPRC 2 first told you back on Jan. 11 about a case of the virus in Harris County. In that case, a local traveler who recently returned from Latin America contracted the virus.
The city said Thursday that a woman, between the ages of 55 and 60 years old, is recovering from the Zika virus.
Officials are discouraging travel to 22 infected areas, including Puerto Rico, for pregnant women and women off birth control, a warning which may last a couple years.
"This particular virus is transmitted to humans by the bite of an infected mosquito. So the mosquito bites an infected person and goes to its next meal and infects that person. We don't have active transmission going on here in Houston though. All the cases we have seen have been imported from Central and South America.” Barton added.
Baylor College of Medicine Dean for the National School of Tropical Medicine, Dr. Peter Hotez said we are at a disadvantage because of the mosquitoes in Houston.
"It's one of the only places in the U.S. that has both kinds of mosquitoes that can transmit Zika virus and it's another reason why I think Houston and the Gulf Coast is uniquely vulnerable when talking about Zika coming into the country," Hotez said.
He said by the end of February, he thinks most Caribbean countries are going to be affected.
Harris County Health and Environmental Services said they're not on alert yet.
During the colder months, they're not spraying and say they haven't seen many mosquitoes with any kind of disease, but discourage people from keeping stagnant water around homes.
Hotez said it poses a bigger threat to areas in poverty.
"Why is that? Well, I think it's probably because when you live in poor quality housing, you'll see windows without screens on them or a lot of holes in the screens, they won't have air conditioning or they'll have box like air conditioning that the mosquitoes can get in and around," Hotez said.
Texas Children's Hospital said they are monitoring patients even if they don't show symptoms.
Symptoms can include: fever, headache, rash and joint pain. 80 percent of people feel no symptoms. It's transmitted when a mosquito bites an infected person and the mosquito carries it to another person. It is not transmitted from person to person.
“The American Red Cross is dedicated to providing the safest, most reliable blood products possible to patients in need," said Dr. Susan Stramer, the vice president of Scientific Affairs at the American Red Cross.
"We are closely monitoring the Zika virus. As a precaution, the Red Cross is currently evaluating whether to ask donors to self-defer for 28 days following their return to the U.S. if they traveled to areas with ongoing Zika outbreaks. The Red Cross and other blood collection agencies are working with the U.S. Food and Drug Administration (FDA), Centers for Disease Control and Prevention (CDC) and state health departments to track Zika and to update donor eligibility criteria as necessary."