Patterns of deer ked (Diptera: Hippoboscidae) and tick (Ixodida: Ixodidae) infestation on white-tailed deer (Odocoileus virginianus) in the eastern United States

Authors: POH, KAREN - Pennsylvania State University; EVANS, JESSE - Pennsylvania State University; MICHAEL, SKVARLA - Pennsylvania State University; Olafson, Pia; HICKLING, GRAHAM - University Of Tennessee; MULLINAX, JENNIFER - University Of Maryland; MACHTINGER, ERIKA - Pennsylvania State University

Submitted to: Parasites & Vectors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/30/2021
Publication Date: 1/20/2022
Publication URL: https://handle.nal.usda.gov/10113/7637260
Citation: Poh, K.C., Evans, J.R., Michael, S.J., Olafson, P.U., Hickling, G., Mullinax, J., Machtinger, E.T. 2022. Patterns of deer ked (Diptera: Hippoboscidae) and tick (Ixodida: Ixodidae) infestation on white-tailed deer (Odocoileus virginianus) in the eastern United States. Parasites & Vectors. 15. Article 31. https://doi.org/10.1186/s13071-021-05148-9.
DOI: https://doi.org/10.1186/s13071-021-05148-9

Interpretive Summary: White-tailed deer (Odocoileus virginianus) host several parasites in the eastern United States, most notably various species of ticks and deer keds. Ticks transmit pathogens to human and animal hosts, but little is known about pathogen transmission by deer keds. Ticks and deer keds may occupy the same host, but there is little information on the distribution of these parasites and their roles in co-feeding transmission of pathogens. This study evaluated tick and deer ked species distributions on naturally infested white-tailed deer and the prevalence of potentially pathogenic bacteria at varying natural densities in different regions. Results from the study provide first evidence of observed niche partitioning of ticks and two geographically distinct deer ked species (L. cervi in the northeast and L. mazamae in the southeast) on white-tailed deer hosts across multiple geographic and body regions. Preliminary molecular results indicate that co-feeding alongside ticks may not be the main method of pathogen transmission to deer keds, but that deer keds may become infected after accidentally or temporarily feeding on hosts that carry pathogens traditionally transmitted by ticks or through vertical transmission. The notable differences in tick and deer ked distributions on white-tailed deer and pathogen infection status may have vector-borne pathogen implications that should be explored because discrepancies could mean different transmission rates of pathogens.

Technical Abstract: Background White-tailed deer (Odocoileus virginianus) host several parasites in the eastern United States, most notably various species of ticks and deer keds. Ticks transmit pathogens to human and animal hosts, but little is known about pathogen transmission by deer keds. Ticks and deer keds may occupy the same host, but there is little information on the distribution of these parasites and their roles in co-feeding transmission of pathogens. This study evaluated tick and deer ked species distributions on naturally infested white-tailed deer and the prevalence of potentially pathogenic bacteria at varying natural densities in different regions. Methods Ticks and deer keds were collected from hunter-harvested white-tailed deer in Alabama, Kentucky, Maryland, Pennsylvania, Tennessee, and Virginia. Deer were divided into three sections (head, front, and rear) and each section was checked for four person-minutes. Statistical analyses identified whether the mean number of deer keds and/or ticks differed across body sections and/or states. Preliminary molecular testing was also conducted in deer keds and ticks collected from Pennsylvania to identify strains of Bartonella, Anaplasma/Ehrlichia, Rickettsia, and Borrelia. Results Deer keds (Lipoptena cervi, L. mazamae) were collected from Alabama, Pennsylvania, and Tennessee. Ticks (Ixodes scapularis, Dermacentor albipictus, Amblyomma americanum) were collected from all surveyed states, with I. scapularis being the predominant species. In general, the mean number of deer keds in the rear section of deer was greater than those found in the front section, while the mean number of I. scapularis found in the head or front sections was greater compared to the rear section. Deer keds from Pennsylvania (L. cervi) were found in all body sections of deer, while deer keds collected from Alabama or Tennessee (L. mazamae) were more often found in the rear section. Preliminary testing for potentially pathogenic bacteria detected various Bartonella spp., Anaplasma/Ehrlichia spp., and Rickettsia spp. strains in L. cervi; however, no Borrelia spp. was detected. Our study reported the first detection of Ehrlichia ewingii in L. cervi in Pennsylvania. Strains of Anaplasma spp., Rickettsia spp., and Borrelia spp. were detected in I. scapularis, while no Bartonella spp. was detected. Conclusions This is the first evidence of observed niche partitioning of ticks and two geographically distinct deer ked species (L. cervi in the northeast and L. mazamae in the southeast) on white-tailed deer hosts across multiple geographic and body regions. Preliminary molecular results indicate that co-feeding alongside ticks may not be the main method of pathogen transmission to deer keds, but that deer keds may become infected after accidentally or temporarily feeding on hosts that carry pathogens traditionally transmitted by ticks or through vertical transmission. The notable differences in tick and deer ked distributions on white-tailed deer and pathogen infection status may have vector-borne pathogen implications that should be explored because discrepancies could mean different transmission rates of pathogens.