Department of Health and Mental Hygiene officials will be spraying various Manhattan and Queens neighborhoods this week in an effort to kill mosquitoes and reduce residents’ possible exposure to the Zika and West Nile viruses.

Starting at 10 p.m. on Wednesday and ending at 6 a.m. on Thursday, the city will be spraying the neighborhoods of Fort George, Inwood, Sherman Creek, Sugar Hill and Washington Heights in Manhattan, according to the Health Department. Simultaneously in Queens, Auburndale, Bayside, Corona, Flushing, Fresh Meadows, Murray Hill, Pomonok and Queensboro Hill will receive the same treatment.

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The city will be spraying adulticide to reduce Asian tiger mosquitoes, which have been found in significant numbers in Health Department traps in the specific areas receiving Wednesday's treatment, ABC7 reported. While the Zika virus has not been found in any NYC mosquito, an insect that is an evolutionary cousin to the Asian tiger mosquito has been to blame for the current Zika outbreak.

"Though the mosquito carrying Zika has not been identified here, nearly a quarter of all positive cases in the continental United States are in New York," Mayor Bill de Blasio said. "As a global city, we must continue to act aggressively with the full support of our federal government, and we hope the other cities will adhere to this model."

In the New York area, most people who tested positive for Zika acquired the infection from mosquitoes in Zika-affected regions, and four contracted it from sexual transmission, the mayor’s office stated. Wednesday’s scheduled pesticide spraying will be the city’s fifth such treatment in a mosquito-dense area.

In the event of bad weather, the pesticide treatment will be delayed one day and will begin on Thursday, ABC7 added.

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At a Tuesday news conference, Mayor Bill de Blasio urged congressional leaders to approve $1.9 billion in funding to combat Zika's spread, saying, "We need federal help so badly. We need the federal government to protect the people of New York City and the entire country," the New York Daily News reported.

During the current Zika outbreak, 489 people have been diagnosed with the virus in New York City — including 49 pregnant women, the Daily News stated. One child has been born in the city with microcephaly, the birth defect marked by babies born with abnormally small heads, which is caused by Zika.