One of the most baffling mysteries in medical science is why hybrid strains or infections with recombinant variants are more effective at evading the immune system and causing severe disease.

Researchers at Sweden’s Karolinska Institutet have discovered how the parasite Trypanosoma cruzi produces different strains that are better at evading the immune system and causing disease. Their results could lead to new ways to diagnose, prevent, and cure Chagas disease, which affects millions of people in Central and South America and kills thousands of people each year. The research was published in the eLife journal.

Chagas disease is caused by Trypanosoma cruzi infection, which produces severe symptoms in the gastrointestinal tract and heart. The parasite has a large number of genes that can vary greatly, allowing it to elude the immune system. However, how it accomplishes this remains a mystery.

A scientific partnership comprising Karolinska Institutet researchers has recently demonstrated that Trypanosoma cruzi can produce novel types that are hybrids of distinct strains. These hybrids are often more effective at evading the immune system and infecting people. The researchers have a precise picture of how these hybrids are created by mapping the genomes of the parental strains and their offspring throughout time. Their findings reveal that the hybrids start off with all of the DNA from both parents, but that the amount of DNA steadily decreases until it reaches the correct level. The researchers also discovered that genetic material is frequently reshuffled in a process known as genetic recombination.

“This knowledge is important,” says principal investigator Björn Andersson, as “the exchange of genetic material can lead to new gene variants that make the parasite more dangerous.”

“A better understanding of how this process works can help us develop new methods for diagnosing, preventing and treating Chagas disease, which is a huge problem in Central and South America.”

The research is based on parasite strains that created hybrids spontaneously in the lab. The researchers used large-scale DNA sequencing to map the whole genome of both the parental parasites and many of their offspring.

“We’ll now be studying material from nature and from patients to map in greater detail how the parasite goes about varying its genes,” he adds. “We’re also working on improving the diagnosis of Chagas disease in Bolivia.”

Image Credit: Getty

You were reading: New Recombinant Variants Have Evolved to Be More Deadly For Humans – Study Warns