Some small U.S. companies are getting an influx in calls — and in some cases, unexpected business — because of fears about the Zika virus.

The virus often produces either no symptoms or mild ones like fever in adults, but an outbreak in Brazil has been linked to a rare birth defect that causes a newborn's head to be smaller and brain development issues. Outbreaks also have been reported in parts of Africa, Southeast Asia, the Pacific islands, and the Americas.

Pest control companies in Texas are getting a surge in business because of concerns that mosquitoes bearing the Zika virus will arrive from neighboring Mexico. The companies are already spraying homes, schools and other properties; usually, they don't start until April.

Darryl Nevins' Mosquito Joe franchise in Houston began getting an increase in calls last week after news reports of seven cases of Zika virus in the metropolitan area. None of the cases resulted from mosquito bites in Texas, the reports said, but people aren't taking chances and want their property sprayed.

"It's not just residential customers, what we primarily had in the past," Nevins says. "Schools, day care, commercial customers with a park nearby are calling and asking, 'What do we do to protect outdoor seating?' "

Nevins says he's getting 15 inquiries a day, which is very unusual for this time of year.

Even in the middle of the summer, he says, the company typically gets only 10 calls a day. Based on the demand Nevins is seeing, he expects to double his staff of four workers to handle the spraying.

In North Austin, Texas, Karyn Brown's Mosquito Squad franchise has been getting calls since mid-January — a marked change from typical years, when the phone doesn't ring until April.

Some of her customers want their property sprayed, while others want information about how mosquitoes spread the virus.

Brown is considering hiring more workers to handle a heavier workload.

"I feel a little guilty — I don't want to profit off something so negative," Brown said.

Jim Grace's travel insurance company is selling more policies known as "cancel for any reason" coverage because of the Zika virus. Unlike regular insurance, it allows a traveler to be reimbursed if they just don't want to make the trip. Grace, CEO of InsureMyTrip in Warwick, R.I., estimates his sales of these policies are up between 15 percent and 20 percent from last year because people are on the fence about vacations or business trips to affected areas.

"As long as it's at least 48 hours before you have to depart," you can say, I'm not going," Grace says.

In many ways, the Zika outbreak is like past outbreaks of disease in that it has created business for some U.S. companies, while hurting others. During the Ebola virus outbreak in West Africa in 2014, companies that sold protective clothing like hazmat suits had increased sales because of demand from customers like medical facilities. On the flip side, companies that arranged safari tours to Africa lost some of their business because would-be travelers were afraid they might catch the disease.

There was some concern in the travel industry that people would cancel some trips to places like Brazil because of the Zika virus.

But the trade group American Society of Travel Agents says its members aren't losing money to the virus so far — they're reporting few outright cancellations, where people, concerned about the virus, cancel trips and don't pick another destination. Still, customers are calling agents with questions about the virus.

"In this case with the Zika virus, if it tracks along the same lines as some other recent travel concerns, there will only be a small shift in booking patterns," spokeswoman Jennifer Michels says. "Some travelers, if they do cancel, will simply ask advice on somewhere else to go and how to best switch their itineraries."

Still, some small businesses are concerned about how the virus might affect travel.

Wedding planner Danielle Rothweiler is worried about her revenue. She's already suggesting that the engaged couples she's working with look at places like Greece rather than Mexico. She's concerned that even if couples have their hearts set on a Caribbean wedding, relatives and friends will balk at traveling to an affected area. Faced with that kind of opposition, many couples are likely to get married near their homes and have simpler weddings, says Rothweiler, owner of Rothweiler Event Design in Verona, N.J. If that happens, she believes she'll lose business.

"The odds that they'll hire a planner for a local wedding are not great," she says.

Joyce Rosenberg is a business reporter for the Associated Press.