In 2019, archaeologists discovered an ancient graveyard with skeletons of 269 children in Huanchaco city in Peru. All these children were the victims of human sacrifice, with their hearts removed before burial.

Five years later, a team of researchers has unearthed another cemetery in the same city. They found a total of 120 skeletons, including both Indigenous Inca people and European colonizers. However, the most surprising findings from this excavation are IG-124 and IG-493, two 1.5-year-old toddlers who died of smallpox. 

Although smallpox is a 3,000-year-old viral disease, Peru didn’t encounter the virus until the 1530s when European colonizers made contact. In the following years, the disease wreaked havoc on the indigenous people inhabiting Peru’s northern coast, killing 70 percent of the population by 1620.

According to the researchers, the toddler skeletons are a rare opportunity to understand the spread of this disease in the New World and its influence on the Chimú-Inka people.

“With the presence of European colonizers and new infectious diseases, there is a disruption of the traditional way of life in the Early Colonial individuals compared to the Chimú-Inka individuals. If we start to identify more of these cases, we can start to create a better understanding of how disease spread and where outbreaks occurred during the early colonial period,” Khrystyne Tschinkel, lead researcher and a visiting assistant professor at Hamline University, told ZME Science.

The toddlers had infections in their bones

About 90 out of the 120 skeletons discovered in Huanchaco are of children and infants. This is because they are more likely to catch the smallpox virus and die from diseases carried by Europeans due to their developing immune systems. 

When the researchers performed a macroscopic analysis of these skeletons, two of them (IG-124 and IG-493) stood out from the rest. The well-preserved skeletons of these two children had signs of thickened bone layers, exposed inner bone cavities, lesions in shoulder joints and bones, bone death, bone expansion at the ends, holes, and new bone growth. 

All these features suggest the children had osteomyelitis variolosa, a type of bone infection characterized by the inflammation and destruction of bone tissues in ankles, feet, hips, wrists, and various other body parts. It is caused by the smallpox virus (variola major). 

“This is quite surprising because currently there is a perception that the fast-acting diseases the Europeans introduced to the Americas do not affect the bones. Generally, this perception is true, however, there are still signs and specific cases, like the two children from this article, where these diseases do affect the bones,” Tschinkel said.

Both IG-124 and IG-493 were one and a half years old and died in 1540, making them the earliest known cases of osteomyelitis variolosa in South America, according to the study authors. 

More information from more burials is on the way

The graves were found near a 500-year-old church built by Spanish colonists. An interesting finding from the graveyard was that many native Inca people, including both toddlers, were buried with Christian reed crosses and beaded jewelry items. This indicates that they were either voluntarily or forcefully baptized and converted to Christianity.

“The combination of Chimú-Inka and colonial mortuary patterns seems to mark a transitional period in identity, before the widespread reducciones (settlements established by Spanish to facilitate the conversion of native people to Christianity), perhaps reflecting some acceptance of Christianity and some resistance to culture change. As we still see some forms of traditional Chimú-Inka mortuary practices, we can postulate there was some agency exerted to hold on to Chimú-Inka traditions,” Tschinkel told ZME Science.

When asked if there are any limitations of the current study, the researchers said there is more to uncover as they have not finished excavating the cemetery. 

“There are many more burials, and more burials means more information. Second, even if we get all the burials, we will not be able to identify everyone with smallpox. As it will not physically show up in every person. Some people will have died before physical changes could take effect,” Tschinkel added.

Hopefully, further research will reveal more valuable insights about the spread of foreign diseases in South America.

The study is published in the International Journal of Paleopathology.