First, the good news: Despite feared cases in Hawaii, New Jersey and Washington, D.C., there is still only one Ebola patient who by all accounts became symptomatic while walking around freely in the United States.

Sure, the hospital sent Thomas Eric Duncan home the first time he came to the emergency room. Sure, a homeless man who had contact with Duncan was missing for a while. Sure, Duncan’s family was quarantined in an apartment with possibly-infected sheets. Sure, the Centers for Disease Control says not to worry.

That’s how you stop it in its tracks,” CDC director Thomas Frieden told CNN Sunday of the agency’s monitoring of those who could have caught Ebola from Duncan. “That’s why we’re confident we won’t see a large number of cases from this.”

But assume for a second that the CDC — a fallible agency staffed by fallible humans — could be wrong. Assume that it may have misjudged the number of Duncan’s contacts, as it did when it said it needed to monitor only “a handful” of people who Duncan put at risk. (The number quickly leaped to 100.) And assume that, as one unnamed federal official told CNN, monitoring flights for Ebola is “not as easy as it sounds.”

Assume, though it may make no sense, that Ebola is a more of a danger in the U.S. than officials think now.  In survivalist parlance, what is your “SHTF plan” — that is, your plan for when the (s)— (h)its (t)he (f)an?

Don’t have one? There are some who do. They sometimes call themselves “Preppers” — the word those devoted to preparing for environmental and/or financial Armageddon usually prefer to “survivalist” — have some advice for you.

Rule No. 1: You’re not crazy — but prep, don’t panic. 

“Panicking is the worst thing to do,” said Daisy Luther, who runs the Web site the Organic Prepper, in an interview with The Washington Post. ” … A lot of people are really getting pretty worked up about this. Being prepared means you don’t need to get really panicked.”

To be clear: Luther is not a crazed militia member adhering to a kooky ideology. She’s a single mom who lives in a rural area not far from Sacramento who “grew up with a full pantry.”

“I live in a cute little Victorian in the country with  great big garden, pets and a chicken coop,” she said. “It’s really just a little country house. Nothing that would really stand out. We believe in home defense, but it’s also not something that would stand out. No walls of gunracks.”

Tess Pennington of the prepper Web site Ready Nutrition also stressed that it’s normal to think ahead.

“There are people that think or preppers in general push fear,” she said in a phone interview. “I believe that they are speaking in an ignorant way.”

Pennington, a former American Red Cross staffer and mother of three, said she went without power for 21 days when Hurricane Ike hit Houston in 2008. She saw fights at gas stations over gasoline. Now she leaves in a rural area near Portland — and is ready for whatever comes.

“I’ve seen people unprepared, desperate,” said Pennington. “That’s why I’m prepping.”

Rule No. 2: Getting ready means getting armed.

“I still don’t think Ebola itself will be the biggest danger,” Scott Kelley of the Web site Graywolf Survival told The Post in an e-mail. Kelley, a vet once deployed to Afghanistan and Iraq, said it’s other people, not exotic diseases, that you have to watch out for.

“The biggest threat to people in the US with regard to Ebola right now isn’t catching it, it’s how others will react and become a threat as well as how government services may be diminished or disappear altogether for a time,” Kelley, who’s based in Phoenix, wrote. “Being self-sufficient and able to protect yourself is really the best way to prepare for Ebola right now, as it is for pretty much any other threat.”

As Kelley pointed out in a piece on his site, a prepper isn’t a prepper without a gun. What’s the point of hoarding necessities if mean dudes with firepower can just take them?

“I can pretty much guarantee you that if you’ve developed a plan to protect yourself and your family against an armed assailant, and it doesn’t involve a gun in some way, that you definitely don’t have the training or experience to be making this plan,” he wrote.

Rule No. 3: Go shopping.

Here’s Luther’s list as it appeared on the Organic Prepper:

Drinking water (1 gallon per person per day)

Food (including items that don’t require fuel for preparation)

Heavy duty garbage bags

Sanitation supplies such as toilet paper, paper towels, baby wipes, and feminine hygiene supplies

Entertainment – you’ll want to be able to keep children and restless family members busy so get craft supplies, books, games, and puzzles

Basic medical supplies

Pandemic kits that contain protective clothing (we have a QuakeKare Deluxe Pandemic Flu Kit for each family member) Our kit is sold out, but this one is similar: Pandemic Virus Kit Module by AXP

Extra N95 masks (3M 1860 Health Care N95 Particulate Respirator and Surgical Mask, Small Adult, 20/Bx, 3M 8511 Particulate N95 Respirator with Valve, 10-Pack, and 3M 8000 Particle Respirator N95, 30-Pack )

N100 masks (3M Particulate Respirator 8233, N100, Moldex 2730 N100 Respirator Mask with Handy Strap Bx/5 Each, 3M 8233 N100 Particulate Respirator – Case of 20)

Nitrile gloves (Dynarex Black Nitrile Exam Gloves, Heavy-Duty, Powder Free, Large, Box/100, Liberty T2010W Nitrile Industrial Glove, Powder Free, Disposable, 4 mil Thickness, Large, Blue (Box of 100)

SafeTouch Nitrile Exam Gloves, Non Latex, Powder Free, Large, Box/100

Safety goggles with an elastic band to ensure a snug fit (Pyramex V2G Safety Eyewear, Clear Anti-Fog Lens With Black Strap/Temples), DEWALT DPG82-11C Concealer Clear Anti-Fog Dual Mold Safety Goggle, DEWALT DPG82-11C Concealer Clear Anti-Fog Dual Mold Safety Goggle, Neiko 53875B ANSI Z87.1 Anti-Fog Approved Wide-Vision Extra-Soft Lab Safety Goggle

Protective clothing: DuPont TY122S Disposable Elastic Wrist, Bootie & Hood White Tyvek Coverall Suit 1414, Size Large, Sold by the Each, Dupont TY120S L Large Tyvek Coveralls Suit, Sold By Each, DuPont Tyvek TY122S Disposable Coverall with Hood and Boots, Elastic Cuff, White, X-Large (Pack of 25)

Antibacterial cleaners such as disposable wipes, bleach, and spray cleaners

Antibacterial hand sanitizer (Purell Pump Bottle, Original, 8 Ounce (Pack of 12))

Rule No. 4: Withdraw from society — but keep busy.

Since the days of the Spanish flu, the best way to avoid disease has been staying away from other people.

“In the event of a pandemic, what people in the preparedness realm recommend is social isolation,” Luther said. ” … No one is supposed to leave the house and come back. There’s a lot more to it than just buying 100 masks and gloves.”

Those unable to leave their homes will need food and their prescription medicine, sure. But they’ll also need somthing to do.

“Most importantly when you prepare for something like this you know if you’re going to be quarantined for 21 days you can thrive in that environment,” Pennington said. In “50 Things to Do During Home Quarantine,”a piece she published on her Web site, worthy ideas include “Make a bucket list” and “Meditate or pray.”