SANTA FE, N.M. — As if bark beetles and low river water levels weren’t enough, there’s another local impact of drought in New Mexico that we can think about – Valley fever. It’s a dust-borne fungal infection, common in the San Joaquin Valley of California and parts of Arizona, but more and more likely to move north through New Mexico, affecting large population centers, such as Albuquerque and Santa Fe, as heat and drought make our soils more welcoming to the fungus.
A 2019 study by a Los Alamos scientist and researchers at the University of California, Irvine documented this expansion, projecting that the fungal infection’s range will likely more than double in the United States, with the list of affected states jumping from 12 to 17, and the number of individual Valley fever cases predicted to grow by 50% by the year 2100. The same research offers a few tools for tamping down the disease’s impact.
The fungus itself finds its way into human lungs when rainfall soaks the ground, allowing the fungus to grow, and then a dry spell triggers it to form spores, which are easily stirred up in dust. Whether gardening, landscaping, doing construction, or merely driving a dusty road, humans (and their trail-following canine companions) can breathe in the microscopic spores.
Within the lungs, the tiny spores expand into ball-like packets called spherules, which divide internally to fill with even smaller endospores. Eventually, in the warm, welcoming environment of the lung, the spherules rupture and release their payload to spread through the body’s surrounding tissue.
What this means for an exposed person is a bout of flu-like symptoms, with coughing, fever, headache, muscle aches, joint pain and fatigue, all of which can look familiar enough to be either ignored, or misdiagnosed. In mild cases, two weeks or more will be required to recover. But the U.S. Centers for Disease Control reports that as many as 40% of people infected with it will need hospitalization. Beyond the flu-like version of Valley fever, for some people, the disease morphs into a serious pneumonia and it can spread into other parts of the body, even the brain, and into serious skin lesions. At Los Alamos National Laboratory, research is underway to explore how potential climate conditions could affect predictions of the number of monthly Valley fever cases in the two highly endemic regions for this disease – the San Joaquin Valley of California and south-central Arizona. Researchers are also working to create a high-resolution risk map of where the fungus is likely growing in the soil, based on climate and soil conditions. This will help disease mitigation by informing the community where extra precautions may be needed to prevent dust exposure.
The Valley fever fungus has been found in New Mexico for more than 60 years, particularly in the southwest corner of the state. Based on the recent number of cases, and taking into account human population in each county, the greatest risk of contracting Valley fever continues to be in southwestern New Mexico, already hot and experiencing the wet/dry cycle that accelerates the fungal growth. Sierra and Luna counties, home of Truth or Consequences and Deming, have had the highest incidence rates, thus far, and the rates are increasing.
Interestingly, the overall uptick in cases could be caused by an increased awareness in our region.
Compared to California and Arizona, New Mexico reports far fewer cases each year; however, a survey in 2011 led by the New Mexico Department of Health reported 66% of clinicians did not feel confident in their ability to diagnose Valley fever in a patient.
Additionally, only 31% of clinicians considered Valley fever when they had a patient that showed signs of a severe respiratory infection. For these reasons, the research team considers that Valley fever cases in New Mexico have been very likely underreported. An increase in cases in 2019 could be a result of higher disease awareness and better reporting. But, overall, increasing both clinician and patient awareness of Valley fever could decrease the time to patient diagnosis, saving both health and cost burdens from this disease. That way, if Valley fever is marching north in New Mexico, we’ll be ready.
Morgan Gorris is a postdoctoral fellow at Los Alamos National Laboratory in the Analytics, Intelligence and Technology division, focusing on Earth system science.