A surge of deadly infections driven by Covid, resistance to drugs and an increase in immunocompromised patients - Harriet Barber reports on the world’s next health crisis.
When 38-year-old lawyer Vikram Trivedi caught coronavirus he was not overly concerned.
But soon after, his left eyeball, a large part of his sinus and the roof of his mouth had to be cut out in a desperate bid to save his life.
The life-changing surgery wasn’t necessitated by Covid-19 or even a bacterial infection; instead it was an aggressive “black fungus” that had taken hold in Trivedi’s immunocompromised body.
The doctors were left with no option but to remove it.
In some ways he was lucky. An estimated 4300 Covid patients lost their lives to the fungus in India during the second wave of the pandemic in 2021.
Public health messaging has historically focused on two classes of pathogen - bacteria and viruses. But as the World Health Organisation (WHO) warned on Tuesday, the risk that fungal attack poses to humans is skyrocketing.
The surge has been driven by Covid, mounting resistance to drugs and an increase in immunocompromised patients.
In an echo of 2018 when it released its priority pathogens list, including “Disease X”, the UN body has published what it regards as the 19 most dangerous fungi.
”Emerging from the shadows of the bacterial antimicrobial resistance pandemic, fungal infections are growing, and are ever more resistant to treatments, becoming a public health concern worldwide,” says Dr Hanan Balkhy, WHO assistant director-general of antimicrobial resistance (AMR).
![Surgery may be an option but typically the fungi kill by infesting the airways and attacking the nervous system, including the brain. Photo / 123rf](https://www.nzherald.co.nz/resizer/v2/YAEOCMHOBBAUTOSLB653QQNWKA.jpg?auth=7dc43c80bae54b9eb2f4fdaff645038f1fb910b0a81ec74bf88add34ddc50184&width=16&height=11&quality=70&smart=true)
The Global Action Fund for Fungal Infections estimates that more than 300 million people suffer a serious fungal infection each year, with 1.6 million deaths annually from the most common infections.
It says a further 25 million of us are at high risk of dying or losing their sight.
Typically the fungi kill by infesting the airways and attacking the nervous system, including the brain.
Alan, 75, has been living with chronic pulmonary aspergillosis for 12 years. He says that the fungal infection, which lies in his lungs, leaves him house-bound in his Northamptonshire home with a permanent cough and bouts of exhaustion.
”It’s flu-like. My body is exhausted, everything aches and I keep falling asleep,” he says.
”It even affects his vision,” his wife, Annie, added. “It’s an invisible illness that’s difficult to explain, for people to understand.”
People whose immune systems have been weakened are at greatest risk of invasive fungal infections, such as those undergoing chemotherapy for cancer or treatment for HIV/Aids.
Alan’s was detected nine months after he had an abscess removed.
”Fungal diseases, particularly the invasive ones, are becoming more and more common, and these are particularly affecting vulnerable, immunocompromised patients,” says Haileyesus Getahun, director of WHO’s AMR Global Coordination Department and one of the authors of the report, in an exclusive interview with The Telegraph.
”Over the last several decades we have increased our capacity to treat chronic infections [like HIV]... and so more and more people are now susceptible.”
Covid-19 is believed to have played a role, too. The reported incidence of invasive fungal infections increased significantly among hospitalised patients during the pandemic, “often with devastating consequences”, according to the WHO.
![The WHO has separated the 19 most worrying fungal pathogens into three categories - critical, high and medium priority. Photo / 123rf](https://www.nzherald.co.nz/resizer/v2/A6OEK5OREFAAPLMIELVPQ2RJIM.jpg?auth=b05310cd8fe4ec0089db1def0f311f5c115ca3c1cd36b8119d5baa417aa35b2c&width=16&height=11&quality=70&smart=true)
Before the pandemic, Dr Shailesh Kothalkar, who worked in Nagpur and treated Trivedi, would see a handful of mucormycosis, or “black fungus”, cases each year. But when the second wave hit, hundreds of patients flooded into his hospital with the disease.
“It was horrible,” he says. “Many of the patients came to us with loss of eyesight, infections in the brain. Patients died.”
The WHO has separated the 19 most worrying fungal pathogens into three categories - critical, high and medium priority - based on the public health burden of the disease, antimicrobial resistance, and the availability of diagnostics.
The four critical pathogens are found in countries across the world, and mostly caught by immunocompromised and critically ill people, such as cancer and organ transplant patients.
The first pathogen is cryptococcus neoformans, which has a mortality rate ranging between 41-61 per cent.
It’s a pathogenic yeast which lives in soil and decaying wood and is caught by inhalation. It affects the lungs and can also spread to the central nervous system and blood.
Candida auris is a yeast with high outbreak potential. Its mortality rate ranges from 29 to 53 per cent and it is resistant to most available antifungal medicines.
Aspergillus fumigatus is a common mould found indoors and outdoors and is caught by inhalation. It predominantly causes pulmonary disease and can spread to the brain.
Mortality rates in those with azole-resistant Aspergillus fumigatus infection range from 47 to 88 per cent. In some studies, up to 100 per cent mortality has been reported.
Candida albicans, meanwhile, can be part of the healthy human microbiome but may cause infections if it multiplies or invades other tissues.
It can produce invasive candidiasis, a life-threatening disease with high mortality, ranging between 20 and 50 per cent.
Yet although cases are rising, there are only four classes of antifungal medicines currently available.
Alan, meanwhile, remains unmedicated 12 years after his diagnosis.
“There are very specific antifungal drugs. The first didn’t work at all,” says Annie.
“The second did work, but it caused serious side effects”.
Without treatment, Alan was forced into early retirement in 2014.
“You don’t know how you will feel from one day to another, how you’re going to be able to react,” he says.
![Dr Tedros Adhanom Ghebreyesus is Director-General of the WHO, World Health Organisation. Photo / 123rf](https://www.nzherald.co.nz/resizer/v2/WYF6ZYTQ5FFYPAN2I2T5NC7EEI.jpg?auth=09302efd8b3aec28d3e1346d82ff9ff3631f79174be9da980e7639f47c9ae93e&width=16&height=24&quality=70&smart=true)
The WHO has warned that resistance to the limited number of medications is rising.
The fungi that cause common infections - such as candida oral and vaginal thrush - have become increasingly resistant to treatment, it says.
Meanwhile, resistance to antifungal medicines is said to be partly driven by inappropriate use in agriculture.
For example, injudicious use of antifungals in agriculture has been linked to the rising rates of azole-resistant Aspergillus fumigatus infections, according to the WHO.
The WHO has now issued a plea for a global effort to prioritise research and development into treatment and surveillance of fungal pathogens.
”Currently, fungal infections receive less than 1.5 per cent of all infectious disease research funding,” the report found, suggesting the true health burden of fungi is unknown, while “most treatment guidelines are informed by limited evidence and expert opinion”.
”We need more data and evidence on fungal infections and antifungal resistance to inform and improve responses to these priority fungal pathogens” says Dr Getahun.