Jenny Durkan, a Democrat, is mayor of Seattle.

On Feb. 28, public health officials in the Seattle area announced the first case of covid-19.

Initially, the number of cases remained small and concentrated in one location. But the threat was already growing.

Now, slightly more than two weeks later, there are 642 confirmed cases statewide, including 387 cases and 35 deaths in our county. But public health officials and Seattle’s best scientists know covid-19 is significantly more widespread than the current level of testing can reveal.

Researchers believe there are actually more than 2,000 cases in our region. Experts expect the number of infected will double every six days. Without any action, 25,000 people could be infected, and 400 people could die by April 7 — just in the Seattle area alone.

That’s why in our region of more than 4 million people, we have taken unprecedented steps to slow the novel coronavirus’s spread.

We have prohibited large events, canceled schools, closed our libraries and community centers, and set up funds to support small businesses, among many other steps.

Across every neighborhood in Seattle, citizens are working to prevent the spread of the virus, to check on their neighbors and to tackle this crisis together.

As the virus will eventually touch every town and city, here’s my best (and sometimes hard-won) advice to other mayors and local officials who are trying to prepare their communities:

Don’t wait to declare an emergency. It may be days before the first case is formally announced, but by then you will have hours to make decisions — not weeks.

Know your region’s capacity to test for this virus now. Be transparent and honest with your residents about that.

Engage your local research community (colleges, private companies and labs) to help scale testing and modeling now.

Speak as one voice across government, and start by telling people how to keep themselves safe.

Act now to prohibit large events and postpone all nonessential gatherings.

Announce clear public health rules for all transit, retail, restaurants and grocery stores.

Ensure your first responders and health-care workers have personal protective equipment; we already face shortages and rationing of gowns, masks and gloves.

Urge telecommuting policies for your workforce and your local employers.

Engage your nonprofits and foundations to create response funds for the most vulnerable and for small businesses.

Ensure all workers know about the new flexibility in unemployment insurance to help provide relief to more Americans affected by the outbreak.

Working with public health officials, thoughtfully prepare to close your schools, community centers and libraries while understanding many families rely on these resources for meals and child care.

Plan for outbreaks in your most vulnerable communities, including senior facilities or shelters for individuals experiencing homelessness. Be prepared to rapidly stand up prevention, isolation, quarantine and recovery sites around your region (We will soon have at least eight of these sites in operation in the city and surrounding King County.)

Repurpose city resources for meals, child care, rental assistance and small-business assistance.

Impose an eviction moratorium so individuals can’t lose their home amid this crisis.

Remember the human toll of this pandemic: People are losing loved ones, our health-care workers are exhausted, and our first responders are putting their health on the line.

Finally, be ready to do more and prepare as best you can for the devastating economic impact. Small-business owners are losing their livelihoods and in some cases their dreams. Working parents are being laid off. And the virus is particularly hard on families and individuals who have no safety net. The fear and anxiety are real.

This global pandemic is the most consequential event faced by the city of Seattle in the past 75 years. It will be for other cities, too.

Seattle, and our state, will recover over time. We will emerge stronger because of our common humanity: the way we are looking out for our neighbors, and the sacrifices so many are making to help save lives.

But it will take united leadership at every step and people acting with both courage and kindness.

Read more: