Mexico’s National Institute of Anthropology and History (INAH) has just made a spine-tingling discovery – the famous traveling exhibit, The Mummies of Guanajuato, may pose a risk of fungal infections to visitors.

INAH experts have found visible fungal growth inside a glass case holding one of the mummies, prompting the institute to issue a warning. The mummies were on display at a tourism expo in Mexico City when the warning was released, adding to the urgency of the situation.

While the intrigue of these ancient corpses is undeniable, it’s crucial to heed the warning and take necessary precautions to avoid any potential health hazards.

“From some of the published photos, at least one of the corpses on display, which was inspected by the institute in November 2021, shows signs of a proliferation of possible fungus colonies. It is even more worrisome that they are still being exhibited without the safeguards for the public against biohazards,” INAH experts told AP News.

The mummies are over 200 years old and usually, these can be viewed at the Museum of the Mummies of Guanajuato (Museo de las Momias de Guanajuato).

However, from time to time they are also exhibited in different places outside Mexico. For instance, in 2009, they were put on display in the US. The INAH experts noticed signs of fungal growth for the first time inside the mummy cases in 2021.

Interestingly, the fungal threat from these mummies is actually a by-product of a burial tax that was imposed on the Mexican people during the 1860s.

How did the burial tax make the mummies a source of fungal infection?

The INAH team suggests that the fact that fungi are able to grow within the cases may be related to their imperfect airtightness. However, another plausible explanation that is also supported by historical data is that these dead bodies were not embalmed during the burial process.

A report from National Geographic reveals that in 1861 a new burial tax was levied on the masses as a fee to the cemeteries for keeping the bodies of their loved ones. 

The cemetery workers used to dig out the dead bodies for which no taxes were paid and put them inside burial chambers in dry soil like mummies. Although the warm and dry environment kept the corpses preserved, since the cemetery workers were not aware of the ancient embalming process, the bodies were not properly mummified leaving scope for various microorganisms like fungi to grow at the onset of favorable conditions.

When the burial chambers were opened, many of the mummies had clothing, skin, hair, and various other body parts intact. It is possible that during the time they were placed in glass cases, some body parts came in contact with fungal spores. However, imperfect airtightness in some cases could’ve also made the mummies susceptible to fungal infection at times they were transported to other countries for exhibitions.  

Mummies spreading fungal infection in humans

No cases of fungal infection in humans from the Guanajuato mummies have been reported so far, but authorities are on the lookout. The INAH team has warned that these mummies pose a risk to human health and that they should be examined for safety. If the mummy cases are really not airtight, the visitors might catch fungal infections from the bodies on display. 

The INAH team said, “This should all be carefully studied to see if these are signs of a risk for the cultural legacy, as well as for those who handle them and come to see them.”  

The concern of INAH experts seems valid because in the past also, people have lost their lives soon after coming in contact with mummies that were probably carrying deadly fungal infections. For instance, in 1970, a team of 12 researchers opened the tomb of King Casimir IV who ruled Poland between the years 1447 and 1492. Surprisingly, within a few weeks, 10 out of the 12 researchers died. 

For now, it’s just a precaution, but authorities strongly want to check the Guanajuato mummies for any such infections.