Cryptic Onchocerca species infecting North American cervids, with implications for the evolutionary history of host associations in Onchocerca.

The research report describes the discovery of a new Onchocerca species that infects cervids (deer family) in North America and discusses the implications of this for understanding the evolutionary history of host associations within the genus Onchocerca. The authors suggest that North American cervids may act as a source for Onchocerca jumping to new host species as well as the possibility of zoonotic infections due to the high density of deer populations.

Discovery of new Onchocerca Species

• The researchers identified a new type of the parasite Onchocerca that infects cervids and is distantly related to the known species Onchocerca cervipedis.
• This discovery was based on DNA sequences collected from infected white-tailed deer in upstate New York.
• The newly discovered species demonstrates a greater diversity of Onchocerca connected with cervids in North America than previously recognized.

Phylogenetic History of Onchocerca Genus

• By analyzing the collected DNA sequences from the new Onchocerca species and those of O. cervipedis, the team reconstructed the phylogenetic history of the Onchocerca genus.
• The evidence suggests that host switches have frequently occurred throughout the evolutionary history of Onchocerca.
• Particularly, the scientists highlight bovid- (relating to the ox family) and cervid-parasitizing species as a significant source of descendant species, suggesting that cervids might have played a key role in the evolution of this genus.

Implications and Further Research

• The discovery points out that North American cervid populations might act as a key source for Onchocerca shifting to new hosts, thereby broadening its reach and impact.
• Given the high density of deer populations, there’s a chance for potential zoonotic infections (diseases that can spread from animals to humans)
• Given the unexpected discovery of this new species from a relatively limited sample, the authors argue for the need for more extensive molecular and morphological surveys to understand fully the diversity of Onchocerca associated with cervids in North America.