The authors of a new World Health Organization report say that climate change is causing health-threatening fungi to spread.

19 organisms that experts identified as being of the greatest threat to public health were listed by the WHO.

The report suggests that the true health burden of fungi is unknown and that most treatment guidelines are informed by limited evidence.

A woman looking at matter under a microscope.

Immune system-evading hybrid viruses have never been observed before.

The World Health Organization's assistant director general of antimicrobial resistance, Dr Hanan Balkhy, said in a statement: "Emerging from the shadows of thebacterial antimicrobial resistance pandemic, invasive fungal diseases are growing ever more resistant to treatments, becoming an ever more pressing public health concern worldwide."

Dr Beardsley said that historical research underspending was out of step with the amount of disease caused by certain types of infections.

He said that they are causing more deaths than Malaria and Tuberculosis.

More than 400 mycology experts and a review of more than 6,000 research papers were involved in the report.

Four of the 19 fungi are considered to be of critical priority. Cryptococcus neoformans is a leading cause of death in people with HIV, and it was included in these.

In patients with high mortality rates, candida albicans is the most common cause of infections in the lung.

There was an increase in the number of infections during the Covid-19 Pandemic. Beardsley said that they saw a spike in the rates of infections in patients who were getting sick, coming in with lung damage and being in intensive care.

There is a disease called Covid-associated pulmonary aspergillosis.

The fourth priority pathogen, Candida auris, was discovered in humans in 2009.

Beardsley said that it hadn't existed before then.

We are still trying to figure out why and how it appeared all over the world.

The report found that the pathogen is resistant to most available antifungal medicines.

The geographic spread of certain diseases was previously limited to certain regions.

Cryptococcus gatii has spread from the subtropics. It was thought to be limited to south-eastern Asia but has been found farther north in China.

It can be because it is being looked for, but I think it is more that it is expanding its range because of climate change.

Increased funding for new antifungals and improved diagnostics will be needed to tackle the diseases.

Beardsley said it was difficult to develop new drugs because of the similarities between the two types of cells.

He said something that will kill a fungus will also kill a human cell.