ASU, Mayo Clinic researchers are working on a faster way to diagnose Valley fever

State health officials say there’ve been more than 7,500 cases of Valley fever reported so far this year. It’s transmitted when people inhale fungal spores living in the ground; the majority of this year’s cases have been reported in Maricopa County. The actual number of cases, though, is likely higher, because diagnosing the fungal disease can be a challenge.

But researchers at Arizona State University and Mayo Clinic are working on a new, faster way to find out if a patient has Valley fever, and the result has been licensed by a company called Cactus Bio.

Doug Lake, a professor at ASU and chair of Foundational Sciences at the new School of Medicine and Advanced Medical Engineering there, joined The Show to discuss more.

Samantha Chow/Arizona State University

/

Samantha Chow

Full conversation

MARK BRODIE: Doug, what's the thought behind this new Valley fever test?

DOUG LAKE: So the thought behind it is, is to have a rapid test because currently the problem is that somebody will, will go into an urgent care or an emergency department and they'll have pneumonia or some sort of maybe a respiratory infection. And the health care provider won't know, is it viral? Is it bacterial or around here, is it a fungal infection like Valley fever? So oftentimes they walk away with an antibiotic, because the testing for Valley fever takes a long time. So it's anywhere between three days and seven days really to get a result back.

So we wanted to make a rapid test that would tell a health care provider, do you give that first dose of antibiotic, or can you tell the patient, oh, you don't need antibiotics, do you need other care, like an antifungal?

BRODIE: Is this the kind of thing that a chest X-ray can't identify? Like if, if you're not sure if it's, for example, pneumonia or COVID or Valley fever, like would a chest X-ray help identify that?

LAKE: Right. So a chest X-ray is pretty much indistinguishable. So, someone could have a pneumonia because of COVID, they could have a pneumonia because of a bacterial infection or, or even something non-infectious, so, so there's no way to tell. I mean, it could even look like cancer, so sometimes people, our health care provider will say, you know, you have a nodule in your lung, maybe you should go see an oncologist. So, and it turns out, you know, the good news is it turns out to be Valley fever, instead of cancer.

BRODIE: So it sounds like your test works kind of on the same principle as sort of the rapid COVID test that many of us became familiar with, except instead of shoving a swab up your nose, you take a blood draw.

LAKE: Yeah, so, that's exactly right. So our test works on a finger stick, and it also works by blood draw. So a person would go in and get normal phlebotomy and, and either plasma or serum would be obtained from that tube of blood and then just a tiny drop of blood on that test and a few drops of chase buffer just like we do with our COVID tests. And 10 minutes later, you know whether you have antibodies to Valley fever. So we're, we're looking for, for antibodies, which is indicative of an active infection.

BRODIE: How certain can one be of the results? Like if, if you have the antibodies, how certain are you that you have Valley fever and conversely, if you don't have the antibodies, how certain are you that you do not have Valley fever?

LAKE: Right. So the test looks for antibodies, as I mentioned. And if antibodies are present, it's very likely that and and symptoms match, for example, a chest X-ray. So there's a constellation of symptoms that people might have if they have Valley fever. They might have night sweats, they might have a cough, extreme fatigue. And along with those symptoms, they also might have a nodule in their chest, you know, by chest X-ray and along with those symptoms if they have a positive antibody test, it's in the high 90 percentile range that they actually do have Valley fever.

And if they're negative and they still have these symptoms, we're also in the high 90 percentile range that they don't have Valley fever, they have something else.

BRODIE: But as you were saying, it sounds like this is not sort of the be all end all. It's a big piece of the diagnosis or ruling something out, but maybe not the only component of it.

LAKE: Right, exactly. So things have to match, right? So, if you come in with a headache only and you do a test, that, you know, that, that may, you can have other symptoms that may be contributory. Bu, a health care provider has to put the pieces together and this test aids in the diagnosis of the disease.

BRODIE: How is this test different than the tests you mentioned earlier that could take maybe three to seven days? Like, are those also looking for antibodies or are they sort of a totally different path?

LAKE: So those tests also look for antibodies, but they have to be sent so that once again a tube of blood would be drawn. So our test uses a finger stick, but it can also, you can also run the test with a tube of blood. So those, the current tests, you have to go in and get phlebotomy and then it's sent to a central laboratory, because only very skilled personnel can do those sorts of tests. They're very complicated and only central labs do those tests.

BRODIE: Are yours more of like an at home kind of thing? Like could I do it in my kitchen like I did with COVID tests, right?

LAKE: So we're, so we're hoping we're gonna get there with an at-home test. Currently we're pursuing FDA, or an FDA regulatory strategy so that we have to march through all the, all the forms and all the FDA regulatory paperwork in order to get approval for either an at-home test or a CLIA-waived test, which would be something that, an urgent care department could do, for example.

BRODIE: Is it the going to that location that takes the time, or is there some new technology that enables the antibodies to either make themselves known or not more quickly than the the tests that we have now?

LAKE: So the first thing is it has to be sent to a central laboratory where a laboratory professional is trained to do those sorts of tests. And, and the other reason is that the tests that we're currently using were developed in the ‘60s. And so things move faster now that we're in 2025 than they did in 1960. So the tests are just the, the nature of the tests are much slower. The nature of the current tests are much slower.

BRODIE: In the world of Valley fever, how important is it to have this kind of test do you think, where somebody can find out quickly and accurately whether or not they have it? And I ask mostly because I know that diagnosis is one of the impediments to people either getting treated or to really even knowing how prevalent this disease is.

LAKE: Absolutely. So this, we hope will really, this test, this rapid test, we hope will be a game changer for, for the, for the diagnosis of Valley fever because currently, even the CDC guidelines start with patients that are not responding on antibiotics. So that means they've already been misdiagnosed.

So we want to avoid that first dose of antibiotic that the patient gets, so that they can be properly diagnosed right away, because as you know, you don't wanna take the wrong drug. If you take the wrong drug, then it's not helping you.

BRODIE: Well, you don't want to take antibiotics if you don't have to also, right?

LAKE: Exactly. And so health care providers are excited about this because it provides an opportunity for proper antibiotic stewardship.