As the weather heats up across the United States, the threat of mosquitoes — and the Zika virus they carry — increases. If good things come in small packages, this potentially costly insect is an exception.

While Zika does not harm most who are infected, it can be damaging to some, particularly to infants, according to the Centers for Disease Control and Prevention (CDC). Among the risks are birth defects, including vision and hearing deficiencies and microcephaly, or an abnormal-sized head.

The disease is spread by mosquitoes, and has reached into the United States in the past decade. A recent study showed that about 10 percent of Zika-infected pregnant women in the U.S. last year carried a fetus or gave birth that suffered defects, The Washington Post reported. Researchers emphasized that pregnant women should take steps to avoid exposure to the Zika virus. A danger to adults is Guillain-Barré syndrome, a disorder of the nervous system.

More than 5,000 cases of Zika were recorded in the United States between January 2015 and May 2017, with more than 4,900 of these brought in by travelers, according to the CDC. Fewer than 100 cases (77) involved nonmosquito transmission, the CDC said. Those transmissions came from sexual contact, congenital infection and laboratory transmission.

Zika virus was discovered in monkeys in Uganda in the late 1940s, and seen in humans in the early 1950s. Cases were sporadic until an outbreak was seen in 2007 on the island of Yap in the Pacific. In early 2016, the spread of the disease led the World Health Organization to declare a Public Health Emergency of International Concern.

The frontline of defense is, of course, against mosquitoes. Measures include wearing insect repellent when outdoors, minimizing time spent outdoors and wearing appropriate clothing outside. Keeping mosquitoes at bay is crucial and can be done with chemicals and by limiting standing water, where the insects breed.

Researchers at Johns Hopkins University recently produced a study indicating that a Zika outbreak in the U.S. could cost more than $183 million to combat, and a severe outbreak could put that number at more than $1.2 billion, The Baltimore Sun reported. In Miami-Dade, Florida, officials estimate the cost of fighting the mosquitoes and the virus they carry at $30 million already, the Miami Herald stated.

With warm-weather states like Florida, California and Texas among the hardest hit in terms of Zika, officials there have allocated funds to prevent the disease. Northern states such as New York are not spared, though, according to Fox News. The state has adjusted its budget to account for efforts against the disease.

The U.S. blood supply has been shown to be safe from the virus, the CDC stated recently. That is illustrated in the statistics stated above, showing minimal cases from blood-borne transmission. No vaccine has been developed against the disease, although testing is ongoing, with hopes that a vaccine could be available by the end of 2017, officials said.

Another method of combatting the disease is altering the genes of the mosquitoes. Scientists have undertaken studies along those lines, taking into account evolutionary dynamics. Still another approach is mathematical, using global weather information to consider where the disease might spread, the FiveThirtyEight website reported.

With mosquitoes on this part of the globe elevated from pests to dangers, caution and prevention must be increased as well.