Epidemic of brain fungus infection hits Africa – 07/14/2023 – Equilibrium and Health

In the 2023 American post-apocalyptic television series The Last of Us, humans are headed for extinction as a brain fungus infection turns most species into zombies. It may sound totally implausible, but fungi can and do infect the human brain.

Fungi are present throughout our environment: in the air, in the soil, in decaying plant material, on our skin and even in our intestines, as part of our natural flora.

Microscopic disease-causing fungi can invade various parts of the body, leading to a range of symptoms and health problems. Yeast infections contribute to an estimated 1.5 million deaths each year.

I’m a neurobiologist who has been studying fungal infections of the brain for 10 years. I was part of a team that recently published an analysis discussing the rise and resurgence of fungal infections in Africa, especially sub-Saharan Africa.

We conclude that Africa suffers from a silent but costly epidemic of fungal infections.

We found that the rise of deadly fungal infections in the region is driven primarily by the high incidence of HIV infections, the virus that causes AIDS, lack of access to quality health care, and unavailability of effective antifungal medications.

What are yeast infections?

For most of human history, fungal infections have not been a threat to human health. That’s because most fungi cannot survive the warm human body temperature of 37°C.

However, climate change and other environmental pressures have led to the emergence of fungal species capable of surviving human body temperature.

Even so, our immune system is capable of fighting yeast infections. For example, our bodies can create localized acidic environments, limit micronutrient availability, and release antimicrobial agents.

However, when the immune system is weakened, fungi are able to bypass the body’s defenses and avoid detection.

They can generate bioactive agents that help them to escape or adjust to the host’s immune response. Some adapt to survive in hostile environments, with little nutrients and oxygen.

Immunocompromised people are at risk of developing serious or life-threatening fungal diseases. Africa accounts for 67% of global HIV cases, and opportunistic fungal diseases are on the rise.

Some examples

An example of an opportunistic fungal disease is cryptococcal meningitis, which emerged with the HIV pandemic in the late 1980s.

Today, sub-Saharan Africa accounts for about 73% of all global cases and deaths resulting from the disease.

Cryptococcal meningitis is caused by the fungus Cryptococcus neoformans, found in soil and bird droppings. The infection occurs when someone inhales fungus spores. Initially, it leads to the development of a lung infection and later to a fatal brain infection.

Cryptococcal meningitis is one of the leading causes of meningitis in adults in sub-Saharan Africa — and is associated with nearly 20% of all AIDS-related deaths.

Effective treatments for cryptococcal meningitis are out of reach for most affected people. Costs range from $1,400 to $2,500 per patient for a full two-week antifungal treatment.

The development of cheaper drugs has been hampered by a limited understanding of how the fungus causes such extreme brain damage.

Another example of an HIV-related opportunistic fungal disease is pneumonia. Pneumocystis jirovecii.

It is caused by a ubiquitous, airborne fungus, the Pneumocystis jiroveciiwhich is transmitted from person to person.

O pneumocystis they hardly cause problems in people with healthy immune systems, but they act as reservoirs and transmit the infection to individuals with weak immune systems, who may develop severe symptoms, including fever, dry cough and difficulty breathing.

Pneumonia due to Pneumocystis jirovecii occurs in 15% to 20% of HIV patients who have breathing problems.

The diagnosis of pneumonia by Pneumocystis jiroveci it is expensive and requires a well-equipped laboratory.

In Africa’s poor urban and rural health facilities, this will be a challenge. the fungus, P. jirovecii, it is also extremely difficult to cultivate, which limits diagnosis and research.

growing burden

In our review, we found several factors that are driving the emergence and resurgence of fungal threats.

These include climate change, the spread of immunosuppressive diseases, medical advances such as organ transplants (the immune system is suppressed to minimize rejection), the use of immunosuppressants to control inflammatory diseases, and the use of antibiotics.

While these factors are not unique to Africa, the burden of fungal diseases and the number of people who succumb to them is much greater.

The Covid-19 pandemic appears to have worsened the global fungal burden. For example, recent studies have shown that people with Covid who have recovered are vulnerable to infection with a fungus called mucormycosisalso known as black fungus.

Covid-induced lung damage, high blood sugar, and the steroids often used to treat them are predisposing factors to black fungus infection.

With a reduced ability to eliminate fungal spores and a reduced immune response, thanks to steroids, the fungus can enter and infect the sinuses and facial bones, eventually moving to the brain.

But don’t we have antifungal drugs?

Most of the population affected by fungal infections live in poor rural or urban settlements.

With underfunded and overburdened health systems, many African countries are not well prepared to deal with yeast infections.

Furthermore, some of the antifungal drugs recommended by the World Health Organization (WHO) —such as flucytosine— are not available in most African countries. Sometimes ineffective and even quite toxic drugs are used instead.

The emergence of drug-resistant fungal strains is also a growing threat. Of great concern is the increase in species of candidate multiresistant, species of Aspergillus resistant to azoles and Cryptococcus clinically resistant.

management strategies

Fungal threats are increasing pressure on healthcare systems that are overwhelmed with a limited arsenal of treatment options.

Health professionals, scientific researchers, policymakers and governments must address gaps in the diagnosis and treatment of fungal infections. This will help improve the ability to deal with them.

* Rachael Dangarembizi is a researcher in neurological infections in the department of physiological sciences at the University of Cape Town, South Africa.

This article originally appeared on the academic news site The Conversation and republished here under a Creative Commons license. Read the original English version.