A common vacation activity for many Filipinos is spending the day around water.

Among their choices, some opt for the comforting. Elderly people are drawn to hot springs for the safety and cleanliness of the free-flowing water and the relief the warm temperature brings to their aching bodies.

Unfortunately, there is more than meets the eye.

In 2023, a group of researchers from the University of Santo Tomas Faculty of Pharmacy discovered the first occurrence of a microorganism called Acanthamoeba in a 72-degree Celsius mud spring and flat rocks, an extreme condition where it cannot thrive.

They presented their study at the annual Congress and EXPO of the Japan Association of Clinical Laboratory and Systems (JACLaS) held in October last year at the Pacifico Convention Hall in Yokohama City, Japan.

Their study earned them the prestigious JaCLaS International Award, alongside other winners from Malaysia, Thailand, Vietnam and Cambodia.

What made this discovery alarming is the threat this microorganism, largely unknown to the public, poses.

Infections in humans, animals

Acanthamoeba is a type of amoeba that can cause infections in both humans and animals. It thrives in temperatures ranging from 42°C to 46°C, which is below its boiling point.

It was found on the Mt. Makiling Forest Reserve in Laguna, a tourist area known for its hot springs. Initially, the research team intended to study the hot spring resorts around the province.

On discovering the microbe, they expressed concern about its potential impact on resorts should it be present in their waters.

Crisselle Marie Celis, one of the researchers, emphasized the significance of the finding, noting that just like any microorganism, an amoeba is supposed to perish when exposed to extreme heat.

She said that in terms of danger, an Acanthamoebae could be likened to a Trojan horse. “When they burst, they carry even more bacteria.”

The high heat index often reported during the summer months may also contribute to increased activity of these microbes, according to Registered Medical Technologist Elyrah Joanne.

Beyond the gut

Contrary to the common association of amoebae with digestive illnesses, Acanthamoeba can infect the eyes, brain and spinal cord.

One of the ailments caused by Acanthamoeba is an eye infection called Acanthamoeba keratitis, which can be acquired by swimming in contaminated water or by using a contaminated contact lens solution.

“Its symptoms are almost similar to other eye infections, like eye pain and redness, so it’s easy to disregard, but it can worsen and lead to permanent vision impairment, even blindness,” an ophthalmologist explained.

However, the opportunistic nature of the Acanthamoebae makes it distinct from other microbes.

If left untreated, the infection can spread to the brain and spinal cord, leading to a condition known as Granulomatous Amoebic Encephalitis.

To date, the study of amoebas in the country is still in its infancy, but Celis’ discovery of an invasive microorganism in a tourist area has raised a public health concern.