Most of the U.S. is months away from mosquito season, but growing concern about the mosquito-borne Zika virus, found mainly in Latin America, is already leading to double- and even triple-digit sales increases and stepped up merchandising for mosquito repellents.

Concern about the virus among Olympic athletes and travelers is also raising questions about whether the disease will hurt the Summer Games in Brazil or marketers plans for the event.

Revenue for the whole pest-control category was up 23% to $32 million for the four weeks ended Jan. 24, according to IRI, vs. 8% for the full 52-week period. Mosquito repellents were only part of that. A warmer-than-usual winter in most of the county through last month also led to surprising growth for an array of lawn and garden products, leading to strong 14% sales growth for Scotts Miracle-Gro last quarter during a traditionally slow season.

But mosquito repellents are really flying off the shelves. Sales of various SCJohnson Off! repellent products soared 47% to 96% for the latest four-week period vs. a year ago, according to IRI. And sales of Spectrum Brands' Cutter mosquito repellents rose an even faster 59% to 138% during the same period.

Zika isn't the only factor pushing up repellent sales, though it's the biggest. An outbreak of dengue fever on the island of Hawaii since November also has been driving demand, and led SCJ to announce yesterday it's donating 54,000 units of Off! for island residents to use.

In Argentina and Brazil, where it's mosquito season already and where the Zika outbreak is widespread, SCJ is increasing production by 400% to 600% over last year's normal levels, a spokesman said.

"We're already seeing significantly higher orders from customers in the southern states in the U.S., which we soon expect to be the case nationally," the spokesman added. To meet those needs, SCJ plants are working around the clock throughout the Americas, he said, and the company is "pursuing easier flow of our products" across national boundaries.

The company also has set up a microsite with information about mosquitos, repellents and the Zika virus.

Retailers are gearing up too. Beginning in March, Target will make bug spray and repellants a centerpiece of its lawn and patio areas in 1,400 stores -- that's about three months earlier than usual, a spokeswoman said.

A Walgreens spokesman said the chain has seen "significant interest and sales of insect repellent in southern markets such as Florida, South Texas, Puerto Rico and Hawaii" beginning in January and heading into the early days of February, which appear largely attributable to the Zika virus.

Of course, what's a boon for bug spray is a potential hazard to many people and events -- among them the Summer Olympics, slated for August in Rio de Janeiro and the marketers with big advertising and promotional plans tied to the event.

Reuters reported on Tuesday that the United States Olympics Committee told sports federations in a conference call last month that athletes and staff concerned about Zika, which has been linked to birth defects in babies born to pregnant women infected by the virus, should consider not going to the games in Rio.

Widespread avoidance of the games by key athletes or travelers is certainly not what Olympics organizers or sponsors want. One of the biggest Olympics sponsors, Procter & Gamble Co., is planning a big multi-brand effort this year as it has much of the past decade, and it has tended to focus particularly on female athletes, given women are key consumers for most of its brands. (Hence the "Thank You, Mom" tagline of past ads.)

"Our overall marketing plans remain unchanged," a P&G spokeswoman said in an e-mail. The company's Zika virus guidance to employees and guests traveling to Rio is consistent with the current World Health Organization and Centers for Disease Control guidance, which urges pregnant women to consider postponing travel to Zika-infested areas, including Brazil. The CDC advises women who may become pregnant to consult their doctors about travel, and advises people generally to use repellents and protective clothing and stay in screened-in, air-conditioned structures when traveling to affected areas. But neither the CDC nor WHO is advising travel bans to affected areas.

Contributing: Adrianne Pasquarelli