In cold blood: Screening wild Alaskan moose ( Alces alces gigas ) for filarial nematode (Filarioidea: Onchocercidae) infections using a deep amplicon sequencing approach

Moose are significant ecological, economical, and cultural animals for the stakeholders of Alaska, United States of America.Thus, the impact of pathogens, like filarial nematodes, are critical areas of moose research.These vector-borne parasites, including Setaria yehi, and Rumenfilaria andersoni, can lead to severe health consequences (e.g., peritonitis).However, little is known about filarial nematode distribution, diversity, and its associated life cycle with Alaskan moose hosts.Newly developed next-generation sequencing techniques offer the ability to efficiently screen multiple species of coinfecting filarial nematodes in a single sample and thus improve our ability to monitor and understand these parasites.Blood collected from wild moose in the Kenai Peninsula, AK, was screened using deep amplicon sequencing with filarial nematode primers targeting the cytochrome oxidase c subunit 1 (cox1) gene.In addition, samples subjected to deep amplicon sequencing (DAS) were also screened using the Modified Knott's Test (MKT).Setaria yehi and R. andersoni, were detected by both diagnostic methods.Overall, 190 moose samples were tested via DAS, with filarioid DNA being detected in 51.58% (98/190) of these.Out of a subset of 138 samples, filarioid nematodes were found in 50.72% (n=70) and 57.25% (79/138) via DAS and MKT, respectively.However, 18 (13.04%)co-infections were detected by deep amplicon sequencing compared to 12 (8.70%)identified via MKT.A deep amplicon sequencing molecular tool for surveillance has several advantages when paired with host blood collection metadata (i.e., years, season, region, host age) to better understand filarial nematode life cycle and ecology.