The virus arrived on the reservation in early March, when late winter winds were still blowing off the mesas and temperatures at dawn were often barely above freezing.
It was carried in from Tucson, doctors say, by a man who had been to a basketball tournament and then made the long drive back to a small town in the Navajo highlands.
There, believers were preparing to gather in a small, metal-walled church with a battered white bell and crosses on the window.
On a dirt road at the edge of the town, a hand-painted sign with red letters points the way: Chilchinbeto Church of the Nazarene.
From that church, COVID-19 took hold on the Navajo Nation, hopscotching across families and clans and churches and towns, and leaving the reservation with some of the highest infection rates in the US.
Crowding, tradition and medical disparities have tangled together on the tribe's land an area nearly three times the size of Massachusetts creating a virological catastrophe.
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And the most basic measures to fight the virus' spread handwashing and isolation can be difficult.
One-third of the homes across the vast, dry reservation don't have running water, forcing families to haul it in.
Many in close-knit Navajo communities live in crowded houses where self-quarantine is impossible, and many must drive hours to the nearest grocery store. To most Navajo, isolating an infected person from their family is deeply alien.
The Chilchinbeto meeting, which brought people together from across the region, included everything from discussions of church finances to a joyful meal of roast beef.
They prayed for strength in the face of the new virus, which seemed like a distant worry.
Instead, it was already in their midst.
We're such a small town. We're so remote, said Evelyna Cleveland-Gray, a Chilchinbeto official who struggled to keep residents from panicking as the virus ripped through the town of about 500, eventually killing more than a dozen people.
We never thought it would hit us.
By now, the loss is felt across the Navajo Nation.
With roughly 175,000 people on the reservation, which straddles Arizona, New Mexico and a small corner of Utah, the Navajo Nation has seen 3,122 cases a rate of nearly 18 cases per 1,000 people. At least 100 people have died.