The story of the encephalitis-carrying mosquito has been fraught with confusion from the start. First we were told that the disease that resulted from its bite was St. Louis Encephalitis, later to hear that it is a less severe disease called West Nile Encephalitis. If the latter, no one seems to be sure how or why it suddenly has appeared in the New York area. Although plans to spray parts of Suffolk County with malathion were announced last week, this week Nassau County announced its plans to spray a lesser insecticide, Scourge, in selected areas. North Hempstead had already hired an exterminating company to treat area ponds with special briquettes that kill mosquito larvae.

On Monday evening, County Executive Thomas Gulotta told North Hempstead Supervisor May Newburger that her town would be sprayed on Tuesday night, between the hours of 6 p.m. and 8 a.m. The spraying was to begin in the Oyster Bay Village of Bayville and continue to the Port Washington peninsula, to include Plandome, Plandome Manor, Plandome Heights, Munsey Park and Flower Hill. On Tuesday morning, Manhasset Superintendent of Schools Dr. Lawrence Bozzomo received word of the spraying from BOCES and ordered after school sports that were to begin at 5 p.m. to be cancelled.

Later in the day the word came from the county executive's office that only Bayville would be sprayed on Tuesday night. The county declined to give a timetable for spraying in other areas, but said it has not been ruled out. When an area is to be sprayed, yellow fliers will be placed in residents' mailboxes informing them of the time the spraying will take place, Mr. Gulotta's office says.

At a news conference in her office on Tuesday afternoon, Supervisor Newburger said that since this does not appear to be an instant emergency, she plans to call a meeting of the North Hempstead village mayors and park district commissioners and try to make a scientific plan for the town. At present residents of areas such as the Great Neck peninsula do not understand why they were not included in the county's plans.

Some reports say that crows that have been found dead in the Long Island region have been found to be infected with the virus. One thing is certain, whether they have died or migrated, the large number of crows that had been living in the Polliwog Pond environs have departed.