Q&A—Why Researchers are Turning Up the Heat on Valley Fever
Coccidioidomycosis (also known as “cocci” or “Valley fever”) is a growing cause for concern in southwestern states such as Arizona and California. According to CDC data, reported Valley fever cases in the U.S. increased by 32% between 2016 and 2018. The CDC cited an increase in community-acquired pneumonia resulting from cocci and estimated that at least 150,000 cases go undiagnosed each year. NIAID is experiencing an uptick in Valley-fever-focused grant applications in response to a funding opportunity (PA-19-083) published in January 2019. The University of California, Berkeley received NIAID awards to support Valley fever research efforts led by Justin Remais, Ph.D. NIAID Now spoke to Dr. Remais about his research and why it’s so important to better understand the epidemiology of this disease.
What is coccidioidomycosis and why is it a public health concern?
Coccidioidomycosis is a disease caused by fungi species in the genus Coccidioides. These fungi grow in the soil in many parts of the southwestern United States, Mexico, and Central and South America. In recent years, reported cases of coccidioidomycosis have risen substantially in regions in the southwest where the fungus grows, for reasons that are unclear. There is currently no vaccine to prevent coccidioidomycosis and no treatment to help patients recover quickly. Furthermore, it remains difficult to avoid breathing in microscopic spores in areas where the fungus is common, which is an added challenge for infection prevention.
How does someone contract cocci?
People and animals contract cocci by breathing in Coccidioides spores. When soil is disturbed by wind, construction or other activities, the spores can be picked up and carried through the air. While many people will have no or mild symptoms after breathing in the spores, others may develop severe symptoms and infections that can take months to go away. Coccidioidomycosis is not contagious and cannot spread between people.
What are some of the symptoms of cocci and can it be confused for another illness such as the flu?
People who breathe in Coccidioides spores may be affected in different ways. Common symptoms include fatigue, cough, fever, shortness of breath, headache, night sweats, muscle aches, joint pain, and rash. Those who experience severe and long-lasting symptoms may also experience long-term lung problems. In the most severe cases, coccidioidomycosis can be fatal. The CDC reported an average of 200 cocci-associated deaths each year in the U.S. between 1999-2016.
Because many of the symptoms of cocci are similar to those of other lung diseases, it can be easily confused with viral illnesses, such as flu, or with bacterial pneumonia. In many cases, cocci can only be distinguished from bacterial or other infections using blood tests that are performed in specialized laboratories. Two studies in Arizona found that 15 to 30% of community-acquired pneumonia is actually caused by cocci. However, because coccidioidomycosis is rarely tested for, these cases may be missed or given the wrong treatment.
What are your lab’s cocci research areas of focus, what questions do you hope to address, and why are these important?
I run a lab focusing on the epidemiology and biology of environmental pathogens. Researchers in my group are working to understand the consequences of environmental change for the spread of tuberculosis, West Nile virus, enteric infections, leptospirosis, coccidioidomycosis, and other important infectious diseases. Researchers in our group, including Jennifer Head and Whitney Mgbara, who each received NIAID support, are conducting epidemiological and computational research in order to understand the shifting dynamics of the disease in a changing California, predict the spatial spread and seasonality of cocci, and characterize the contribution of zoonotic (animal) hosts to the transmission of cocci. In California and much of the West, we are witnessing an historic increase in coccidioidomycosis cases, making it imperative that we address fundamental questions surrounding the epidemiology, environmental biology, and ecology of Coccidioides.
As a soil-dwelling fungus, Coccidioides depends on favorable ground conditions to establish, grow, and spread. We are only beginning to understand the specific conditions that support the proliferation of the fungus and its spread in airborne dust. We are working to understand how extreme conditions—including prolonged drought and wildfires—may favor its growth and dispersion, and determine which dust exposures pose the highest risk of infection. In another line of research, our group is working to better understand the seasonal rise and fall of cocci transmission, allowing us to build models that predict transmission risk over time across California to better target disease surveillance.
What research developments do you hope to see in the next several years based on these areas of focus?
One of our recently funded projects centers on two core epidemiologic studies to be conducted in California: a retrospective study of more than 65,000 cocci cases that occurred between 2000 and 2018 to determine key environmental and demographic drivers of cocci transmission; and a prospective study to estimate the fungus exposure-response relationship within key high-risk subgroups. A major goal is to inform the public health response to the current epidemic through the design of improved surveillance and environmental interventions.
The recent increase in coccidioidomycosis cases in California underscores the need to address gaps in our understanding of the environmental transmission of Coccidioides. In addition, the COVID-19 pandemic, caused by the novel coronavirus SARS-CoV-2, is raising new concerns about the risk of viral and fungal respiratory co-infections. It is not yet fully understood how cocci and COVID-19 infections interact, but concerns have been raised about overlapping risk factors, severity of co-infections, and diagnostic and surveillance challenges. We hope to better understand how the epidemiology and etiology of cocci and COVID-19 may intersect this fall, in both populations and individuals, and how precautions like mask wearing and increased time spent outdoors may influence the risk of both infections.
NIAID is supporting this research through grants R01 AI 148336 (plus an additional supplement) and F31 AI152430.
For a list of references, view this article on the National Institute of Allergy and Infectious Diseases website.