Can Cordyceps Infect Mammals? Science Fiction and Science Fact: How to Tell the Difference
The following is a brief introduction to the topic:
The idea of a “zombie” fungus that can take over the behavior of its host has captured public attention, especially through popular culture such as “The Last of Us and the HBO video game”. This story revolves around Cordyceps, a mutated fungus which jumps from insects onto humans and causes a pandemic. How much of the story is based on scientific fact? Cordyceps is a real fungus with fascinating parasitic abilities, but its threat to mammals (including humans) is often misunderstood. This article explores the Cordyceps fungus, its history and medicinal uses, as well as the risks that it poses to mammal. It also answers the question “Can Cordyceps infect mammals” real-world fungal threat experts are concerned about today.
Understanding Cordyceps, the Entomopathogenic Fungus
Cordyceps, a genus containing over 400 species of ascomycete (sac) fungi, is parasitic in nature and targets insects and arthropods. These fungi infect and kill insects. Cordyceps’ life cycle begins when the spore falls on an appropriate host such as an ant or beetle. The spore penetrates the exoskeleton of the host and eventually replaces its tissue with mycelium. The fungus manipulates host behavior as it grows. It often forces the host to move to a place that is ideal for fungal growth. Ophiocordyceps univocis, a fungus that was previously classified as Cordyceps, forces infected ants (or other insects) to climb up vegetation and clamp before the fungus releases spores.
Cordyceps Characteristics
Cordyceps & Mammals: Biological Barriers
Cordyceps cannot leap from infecting insect to infecting mammal due to a number of fundamental barriers.
1. Thermal Limitations
Cordyceps fungi have evolved to survive in insect bodies that are much lower than the temperatures of mammals. Most Cordyceps are inhibited or killed by humans and other mammals who maintain an internal temperature of 37 deg C. According to infectious disease specialist Dr. Scott Roberts “Most fungal spp. cannot grow above 98.6 degree Fahrenheit”. Some mycologists even hypothesize that this is the reason we evolved to have a body temperature of 98.6 degrees Fahrenheit.
2. Host Specificity & Evolutionary Adaptation
Over millions of years, Cordyceps has co-evolved alongside their insect hosts. They have developed highly specialized mechanisms that allow them to manipulate insect behavior and evade their immune systems. Insects have a vastly different physiology, genetics, and immune response. Mammals, for example, have adaptive immune systems, physical barrier like skin and cellular defences that can recognize and destroy fungi pathogens. Cordyceps cannot adapt to cause infection in mammals due to these differences.
3. Immune System Defenses
The immune system will likely neutralize Cordyceps even if it were to invade a mammalian’s body. Macrophages and neutrophils are capable of phagocytizing fungal spores. Mammals also exhibit cultural and behavioral adaptations that limit their exposure to environmental fungi (e.g. hygiene practices).
4. No person-to-person transmission
Fungal infections are not as contagious as viruses like influenza or SARS CoV-2. Cordyceps infections can be acquired through the environment and not by other infected people. This limits the possibility of a pandemic scenario.
Cordyceps: Medicinal Uses, Bio active Compounds and Other Information
Cordyceps, despite its inability infect mammal species, has been revered in traditional Chinese medicine for its many health benefits for centuries. Bio active compounds are harvested or cultivated from species like Cordyceps Sinensis, (now classified as Ophiocordyceps Sinensis).
Key Bio active Components:
Cordycepin is a nucleoside analogue with anti tumour and antimicrobial effects demonstrated in pre-clinical research. It is being studied for its potential use in cancer treatment, viral inhibition (including SARS CoV-2) and neuro protection.
Polysaccharides These compounds, like b glucans, have immunomodulatory properties, which enhance the body’s defence mechanisms without overstimulating the inflammation.
Ergosterol A precursor of vitamin D2, ergosterol is anti-inflammatory and antioxidant.
Potential Health Benefits:
Cordyceps Extracts Show Promise in Mitigating Oxidative Stress and Noninflammatory In Models of Neurodegenerative Diseases like Alzheimer’s or Parkinson’s
Cordycepin is antiviral It has been shown in lab settings that it inhibits the replication of viruses such as dengue and SARS CoV-2.
Energy and Stamina Traditional uses include boosting stamina and libido. However, robust clinical evidence on this is limited.
Table: Cordyceps Bio active Compounds and their Potential Effects
Compound Potential Benefits Status of Research
Cordycepin Pre-clinical and In vitro Anticancer, antiviral anti-inflammatory, Neuro- protective Cordycepin
Polysaccharides Antioxidant, immunomodulation, anti-fatigue Traditional and pre-clinical use
Ergosterol Antioxidant and anti-inflammatory Pre-clinical
Adenosine Cardiovascular Protection, Anti platelet Aggregation Pre-clinical
The Real World Fungal Threats – Why Cordyceps isn’t a Concern
Experts in health are becoming increasingly concerned about other fungi pathogens, even though Cordyceps is not a significant threat to mammals. Fungal infections are a growing issue for public health, especially among immune compromised people.
Emerging Fungal Pathogens:
Candida auris is a multi-drug resistant yeast that causes severe bloodstream infection with high mortality rates. It is resistant against common antifungals, and disinfectants. This makes it difficult to control outbreaks.
Aspergillus fumigatus: A mold which causes aspergillosis in patients with immunocompromised immune systems, leading to respiratory failure, and systemic infection.
Coincides is the cause of Valley Fever, an endemic respiratory disease in parts of Latin America and the Southwest United States. Climate change has expanded its geographical range.
Fungal threats:
Climate Change: Rising temperatures around the world may enable fungi adapt to warmer environments and survive on humans. Candida auris for example emerged simultaneously on three different continents. This could be due to thermal adaption.
Anti fungal Resistant: The overuse of antifungals, both in agriculture and in medicine, has resulted to resistance. This limits treatment options.
Immunocompromised populations: An increasing number of people with weakened immunity (due HIV/AIDS or chemotherapy) are more susceptible than others to fungal infections.
Table of WHO’s Priority Fungal Pathogens
The primary hosts of a fungus pathogen are key concerns
Candida auris Immunocompromised humans Drug resistance, healthcare-associated outbreaks, high mortality
Aspergillus fumigatus Respiratory infections in immunocompromised people
Coccidioides spp. Coccidioides spp.
Cordyceps: A Perspective
Science fiction is unlikely to be able to explain a Cordyceps epidemic infecting mammalians. Cordyceps is unlikely to be able to adapt and infect humans, or any other mammal, due a number of biological barriers, including host specificity, temperature sensitivity, and immune defenses. Cordyceps is still of interest because of its medicinal properties. Research continues to explore its bio-active components for therapeutic applications.
Pathogens such as Candida auris or Aspergillus fumigatus pose significant threats to populations that are vulnerable. Climate change and anti fungal resistant are escalating these threats. Therefore, it is essential to increase research, surveillance and public health preparedness. Cordyceps is a fascinating plant with a rich cultural history. For the time being, however, we don’t have to worry about a zombie invasion.
Disclaimer: This is an informational article and not medical advice. Before using Cordyceps, consult a healthcare professional. This is especially important if you are on medication or have an underlying condition.