This is a big week for creatures of all kinds: Horses are due for another protective injection. Birds of the corvid or raptor groups could begin to die at any time. And the mosquitoes that carry West Nile virus, primarily the night-biting Culex tarsalis, are already testing positive in some states, meaning they could reach Utah soon.

It's time for people to pay attention to protecting themselves.

Today, the Division of Wildlife Resources will issue a plea for people to report certain kinds of dead birds, including jays, magpies, crows and small raptors such as hawks that might have been felled by West Nile virus. In three weeks, the state Department of Health will start checking its sentinel chickens. They've already begun an ad campaign aimed at getting people to wear DEET mosquito repellent.

And mosquito abatement pros have been in the field for weeks, identifying areas where mosquitoes have over-wintered and laid eggs, so they can be destroyed before they start biting birds, horses and people.

The virus is carried by mosquitoes and spread to birds, humans and horses through biting. People can also, on rare occasion, receive the virus from a blood transfusion or transplant, mother to baby in the womb or by a needle stick.

It has deadly potential, though very few of those bitten by an infected mosquito will show even mild symptoms. Fully 80 percent of those bitten by an infected mosquito will have absolutely no symptoms. Nearly 20 percent will have symptoms of West Nile Fever: headache, fever, muscle aches, nausea, vomiting, eye pain, but will usually recover completely within a week. About 1 in 150 people who are infected will show neurological symptoms such as meningitis, encephalitis or acute flaccid paralysis from spinal cord damage. And 10 percent of those few — about 1 in 1,000 infected people — will die, according to state epidemiologist Dr. Robert Rolfs.

The virus first appeared in Utah last year. Historically, the second year is the worst for human infection. So a consortium that includes health, wildlife, agriculture, mosquito abatement, environmental quality, the Bureau of Land Management and other officials is taking it very seriously

The first new generation of Culex tarsalis mosquitoes has already been born, according to Sam Dickson, manager of the Salt Lake City Mosquito Abatement District, which began seeing "lots of larvae" last month. Because of the weather, the pesky biters are actually three or four weeks ahead of schedule. Abatement staffers are busy destroying breeding grounds — something they hope people will do in their own yards, as well.

State veterinarian Mike Marshall hopes that owners gave their horses the first inoculation around April 1. It's now time for the second dose, with another due in August, if it's the first year a horse has been inoculated. Otherwise, it needs one in spring and one around Aug. 1. That has to be done every year.