Pathogenic Mold Is Becoming a Global Health Priority
Cesar Collado
March 6, 2023
Fungal apocalypse evolves from insect to video game to TV series "The Last of Us"

Pathogenic Mold Threats: Truth or Fiction?


Recently, a popular video game turned HBO Max Series, “The Last of Us”, fictionalized the possibility of a pathogenic mold that causes a “fungal apocalypse”. In the show, the fungal pathogen found in insects, Cordyceps, evolves to infect humans and turns those stricken into violent zombie-like creatures that spread it to others through bites. Society collapses in a matter of days after the fungus emerges.

This fictional leap of science from insect to human pathogenic mold is highly unlikely with scientists expressing little concern for such a scenario. However, the show does accurately portray a number of factors that are relevant today. These include climate change, drug resistance, and very few reliable anti-fungal agents.  There are increasing health risks associated with pathogenic molds or fungi.

Pathogenicity of Mold

The pathogenicity of mold is characterized by reproduction inside the human body and colonizing. Mold colonies have been removed surgically from lungs, sinuses, and brain tissue. When mold enters the body, it can have several roles in impacting human health:

  • Mold as an Allergen: Some people are allergic to mold.  As a result, the body will develop antibodies to mold allergens.  These antibodies can be tested for with immunoglobulin blood testing for food and allergens.
  • Toxigenic Mold: Some molds produce secondary metabolites that are chemical and gas toxins.  These potent chemicals can be potent toxins ingested or released inside the body that can impact the health of several human organ systems including the brain.
  • Pathogenic Mold: Some molds can find the human body a breeding ground to colonize.  The human body has several places that are warm and moist with plenty of organic matter for food leading to the reproduction and development of mold colonies.

Mold diagnoses are typically made through a combination of physical examination, medical history, and laboratory tests, such as a chest X-ray, CT scan, or blood tests. 

World Health Organization

The World Health Organization (“WHO”) is an agency of the United Nations, established in 1948 to promote health and control communicable diseases. It is supported by 194 member nations that focus on keeping the world safe and serve the vulnerable – so everyone, everywhere can attain the highest level of health. The programs research budget is approximately $6.7 B in 2023 and focuses on unmet research and development (“R&D”) needs to address diseases that are often neglected by public and private R&D due to resources, market considerations, and profitability concerns with serving the entire world, including poorer developing countries.

WHO Fungal Priority Pathogen List

WHO pathogenic mold priority list

In 2022, the WHO published a prioritized list of 19 fungi that pose the greatest threat to human health. The global criteria for selection include:

  • Deaths
  • Annual Incidence
  • Global distribution
  • Growth Trends (past 10 years)
  • Requirement for Inpatient Care
  • Complications and consequences
  • Antifungal resistance
  • Preventability
  • Access to Diagnostics
  • Evidence based treatment

Overlap with PCR Testing Standards (ERMI and CAP testing)

In the US, the laboratory standard test for precision is considered to be DNA or genetic testing.  DNA testing is very specific to the species tested, which has limitations as “cousins” or species relatives of any fungi genus are not recognized by PCR technology.

ERMI (Environmental Relative Moldiness Index) Testing was developed as a research tool to compare household mold contamination in different geographies with a common scale.  It was never intended to become a standard; however, with the absence of a common standard testing method, ERMI has become a test of choice amongst some physicians, mold remediators, and Indoor Air Quality (“IAQ”) professionals. The panel of pathogenic molds is comprised of the few known fungi species with sequences and evidence of human harm.

ERMI Panel

  • Acremonium strictum
  • Aspergillus versicolor
  • Penicillium chrysogenum, svar.2
  • Alternaria alternate
  • Aureboasidium pullulans
  • Penicillium corylophilum
  • Aspergillus flavus/oryzae
  • Chaetomium globosum
  • Penicillium crustosum/camembertii
  • Aspergillus fumigates, Neosartorya fisheri
  • Cladosporium cladosporioides, svar.1
  • Penicillium purpurogenum
  • Aspergillus niger/ awamori/ foetidus/ phoenicis
  • Cladosporium cladosporioides, svar.2
  • Penicillium glabrum/spinulosum
  • Aspergillus ocharaceus/ostianus
  • Cladosporium herbarum
  • Penicillium variabile
  • Aspergillus penicillioides
  • Caldosporium sphaerospermum
  • Rhizomes stolonifer
  • Aspergillus restricts/ caesillus/ conicus
  • Europium (Asp.) amstelodami group*
  • Scopulariopsis brevicaulis/fusca
  • Aspergillus sclerotiorum
  • Epicoccum nigrum
  • Scopulariopsis chartarum
  • Aspergillus sydowii
  • Mucor amphibiorum
  • Stachybotrys chart arum
  • Aspergillus unguis
  • Paecilomyces variotii
  • Trichoderma viride/ atroviride/ koningii
  • Aspergillus ustus
  • Penicillium brevicompactum/stoloniferum
  • Wallemia sebi

It is important to note that the selection of pathogenic molds for the panel emphasized mold’s proclivity to colonize in water damaged homes constructed with standard building materials.

There is also a more economical CAP Analysis derived from the ERMI panel. CAP is derived from the names of these dominant fungi: Cladosporium – Aureobasidium ‐ Penicillium.

The CAP mold tests capitalize on the same panel used by ERMI testing.  However, smaller CAP panels, such as CAP 2, CAP 14, CAP 15 can be utilized to cut expenses of a 36 mold panel.  This approach is more than a panel.  It is a method of interpreting data that allows mold professionals to use panels with fewer species than the ERMI panel of 36 species. The flexibility to use smaller panels for analysis without losing the ability to diagnose the home can be cost effective.  

It is an obvious observation that only two species from the WHO Fungal Priority Pathogen List are commonly tested for by most mold professionals in the US.  These pathogens are the greatest global threat to human health and have higher importance in the developing world.

Benefits of Mold Culture Plates and Microscopy Analysis

While ERMI provides precision in identifying molds contained in the panel, analysis by microscopy allows for the observation of any mold that has a cell wall (which is all molds).  This enables a broader scope of possibilities that include related species. However, microscopy is only able to report on a genus level, not by species.

Microscopic view of mold spores

While species level precision is not possible, the knowledge of the presence of mold colonies of certain species can be helpful in diagnosing potential illnesses. It is estimated that microscopy allows for the potential identification of mold presence of 36,000 species. With current mold remediation practices, the resulting removal remains the same regardless of mold species present. Read more about mold testing methodologies HERE.

Mold Plates and Candida Albicans

One specific benefit of mold testing using culture plates is the identification of Candida Albicans.  These small, microscopic colonies commonly appear on plates.  It is important to note that the Candida source is not typically from water damaged building materials.  It usually comes from the body of people or pets that occupy the building. Candia overgrowth in the human GI tract is common, as is oral thrush.  It is possible that the mold health issues are the result of a candida overgrowth from antibiotic use, from infection inside the gut, or from a poor diet (e.g. – high amounts of sugars or other simple carbohydrates).  Read more about Candida overgrowth in the gut HERE.

Microscopic view of Candida Albicans

ImmunoLytics Mold Testing Kit 

ImmunoLytics provides the industry’s most complete mold plate and swab testing kits with easy-to-understand step-by-step instructions.  Analysis includes a detailed report of how to interpret the analysis and free phone consultation throughout the process.  

ImmunoLytics Mold Test kit includes mold plates, swab, instruction sheets, and seals.

Pathogenic Molds That Are Currently a Threat to Human Health in US


One of the most common fungal pathogen infections is aspergillosis.  Aspergillosis is a fungal infection caused by the fungus Aspergillus. This fungus is commonly found in the environment, including in soil, water, and decaying organic matter. Aspergillosis can affect both humans and animals, and it can range in severity from mild allergic reactions to severe, life-threatening infections.

Common human fungal infections


In some cases, the infection can be severe and require surgery to remove the affected tissue. Surgery for aspergillosis removal is usually done to remove a mass of infected tissue that has formed in the lungs, sinuses, or other parts of the body. The surgeon may also remove any other tissue that has been affected by the infection, such as lymph nodes. In some cases, a surgeon may also need to remove part of the affected lung or other organs to control the spread of the infection. 

After the surgery, the patient may need to take medications, such as antibiotics or antifungal medications, to help fight the infection. In some cases, a course of steroids may be prescribed to reduce inflammation and speed healing. It is important to follow the doctor’s instructions carefully to help ensure a successful recovery.

Candida Aureus

The incidence and mortality of Candida aureus is a recent topic and has not been well documented to date.  As a result, it has only been reported in recent years in the US.  Candida aureus is a species of yeast that can cause infection in humans and is a rare cause of invasive fungal infections. Thus, immunocompromised patients are the most vulnerable.  This includes patients with autoimmune disease, cancer, elderly, children, and any sick hospitalized person.

Most infections due to C. aureus are superficial and can be treated with antifungal medications. However, serious invasive infections can occur and can be fatal. The mortality rate for invasive C. aureus infections is very high and has been reported to range from 12-55%.


Valley fever is a fungal infection caused by the fungus Coccidioides. It is endemic to certain areas of the southwestern United States, including Arizona, California, Nevada, New Mexico, Texas, and Utah.  According to the Centers for Disease Control and Prevention (CDC), an estimated 10,000 cases of valley fever are reported annually in the United States. However, because many cases go undiagnosed or unreported, the actual number of infections is likely much higher.

Coccidioidomycosis or "Vally Fever"

Certain populations, such as people with weakened immune systems, pregnant women, and certain ethnic groups, may be at higher risk for developing severe or disseminated disease. Valley Fever can lead to severe disease and even death.  In addition, certain occupations, such as construction and agriculture, may also increase the risk of exposure to the fungus.

The incidence of valley fever can vary depending on a variety of factors, including climate, geography, and human behavior. Outbreaks of valley fever have been associated with dust storms, construction and excavation activities, and other disruptions of soil that can release the fungus into the air.  The most severe form of valley fever is disseminated coccidioidomycosis, which occurs when the fungus spreads from the lungs to other parts of the body, such as the skin, bones, and brain.