A footworm in the door: revising Onchocerca phylogeny with previously unknown cryptic species in wild North American ungulates
Bibliographic record
Abstract
• A robust molecular analysis was performed to reinterpret the evolution of the genus Onchocerca. • We discovered a novel Onchocerca sp. in North America infecting wild cervids. • At least four Onchocerca spp. have been misidentified as Onchocerca cervipedis. • Novel host-parasite assemblages are distributed across Canada and the United States. • We demonstrated molecular marker utility for diagnostic and/or evolutionary questions. Onchocerca is an important genus of vector-borne filarial nematodes that infect both humans and animals worldwide. Many Onchocerca spp., most of medical and veterinary health relevance, are the focus of a variety of diagnostic and molecular research. However, despite the importance of these parasites, there is growing evidence of previously unexplored genetic diversity of these nematodes, particularly among wild ungulate hosts in North America. These understudied parasites prevent us from comprehending the evolutionary history of the genus Onchocerca , monitoring potential One Health threats, and improving our filarioid diagnostic capabilities. In order to fill these knowledge gaps, we identified five uncharacterized Onchocerca lineages and compared them with other well-known filarioid species using single and concatenated gene regions (i.e., nd5 , cox1 , 12S, 18S, 28S, hsp70 , MyoHC , rbp1 ). Phylogenetic analyses revealed that the novel Onchocerca lineages of wild North American ungulates segregate into two clades. One clade comprised Onchocerca lineages II, IV, and V and other species found mainly in domestic animals and humans, and the second comprised Onchocerca lineages I and III and other species from a variety of hosts including cervids, bovids, and equids. The formation of two clearly separate clades supports the idea of at least two independent expansion events of ancestral Onchocerca spp. into the North American continent via the Bering land bridge. Cophylogenetic analysis shows evidence of ancestral Onchocerca spp. of Bovidae host-switching to wild Cervidae and giving rise to the novel Onchocerca spp. Lastly, pairwise analysis confirms informative molecular markers of diagnostic relevance in both mitochondrial and nuclear gene regions of filarioid nematodes. The overall information provides greater context to the genus Onchocerca and emphasizes the need to discover, characterize, and monitor neglected parasites, especially those of wildlife origin.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".