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

Interactions between the autochthonous deer ked Lipoptena cervi and the alien L. fortisetosa (Diptera: Hippoboscidae) ectoparasites of Cervus elaphus in Italy: coexistence or competition?

The autochthonous Lipoptena cervi and the allochthonous Lipoptena fortisetosa in Cervus elaphus in Central/Northern Italy were studied during autumn and winter 2018-2020 in order to evaluate the possible interactions between the two parasite species and the possible influence of geographical parameters on their abundance. This survey could help disentangling whether the coexistence between the two species will be possible or the competitive exclusion of L. cervi is to be expected. The results show that L. cervi is influenced by host sex and age and is more abundant at higher altitudes, while L. fortisetosa is more abundant in lower altitudes and in southern/eastern areas. The interaction between the two species is evident and symmetrical but mild at the component community level, while at the infracommunity level an asymmetric competition has been evidenced by the displacement of L. cervi when L. fortisetosa is present in the same body location. Geographical clusters of L. fortisetosa are evident in plains near urbanized areas, while L. cervi distribution appeared more scattered in all the Apennine ridge. Our observations indicate that the two deer ked species not only can coinfect the same host population but also the same host individual, avoiding strong direct interaction and competitive exclusion. All the observed patterns reflect different adaptations to environmental conditions and possible strategies to minimize competition. However, longitudinal surveys are needed to evaluate if the observed pattern is a constant feature or a result of the sampling seasons.

First report of the deer ked, Lipoptena cervi, and associated pathogens in southern Québec, Canada

Deer keds (Lipoptena cervi), an introduced European species, are expanding their geographic range in North America. We document their first recorded presence in Québec, Canada, map their distribution, and highlight the detection of pathogens of potential public health relevance. In the Estrie region of southern Québec, 47 deer keds (L. cervi) were collected from 14 (5.5%) of 254 harvested white-tailed deer (Odocoileus virginianus). Borrelia spp. and Anaplasma phagocytophilum were detected in the body of 1/44 and 8/44 L. cervi specimens, respectively. A statistically significant spatial cluster of white-tailed deer infested by L. cervi was found in southern Estrie using the Bernoulli-based spatial scan statistic.

Cleaning Interactions Between Crows and Sika Deer: Implications for Tick-Borne Disease Management

Cleaning interactions between mammals and birds have been widely observed worldwide. Here, we report cleaning interactions between sika deer and crows in Japan, based on a field observations using camera traps and online research. Online research was performed on social media platforms such as X (formerly Twitter), YouTube, and personal blogs. We finally collected 27 cases of cleaning associations between sika deer and crows. Crows associated with male more than female deer and mainly pecked their heads or necks, suggesting that crows remove Ixodid ticks from the deer's surface. Given that ticks on sika deer are vectors of several zoonotic pathogens such as Rickettsia and Borrelia spp., further studies should be conducted to examine the roles of crows as biocontrol agents of ticks and tick-borne diseases.

Detection of Anaplasma phagocytophilum DNA in Deer Keds: Massachusetts, USA

Deer keds (Lipoptena spp. and Neolipoptena ferrisi) are hematophagous ectoparasites that primarily infest white-tailed deer (Odocoileus virginianus) and other cervids in the United States. The distribution of deer keds in the northeastern United States and the pathogens they harbor remains relatively unexplored. In this study, we examined the geographical distribution and pathogen prevalence of deer keds in Massachusetts by collecting samples from white-tailed deer and testing for tick-borne pathogens. Deer keds were collected across the state, including in four previously unrecorded counties, indicating a wide distribution. Pathogen screening revealed the presence of Anaplasma phagocytophilum DNA in 30% of the keds, but no other pathogens were detected. The medical and biological significance of detecting A. phagocytophilum DNA in deer keds requires future studies. This research provides a baseline for the distribution and pathogen prevalence of deer keds in Massachusetts and highlights the potential of deer keds as sentinels for monitoring deer-associated microbes.

Passive Surveillance of SARS-CoV-2 in Adult Blacklegged Ticks (Ixodes scapularis) from Northeast Pennsylvania

Monitoring the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wildlife is vital to public health. White-tailed deer (Odocoileus virginianus) in the United States have tested positive for SARS-CoV-2, and their interactions with blacklegged ticks (Ixodes scapularis) raise the question of whether or not these ticks also carry SARS-CoV-2. In this study, 449 blacklegged ticks from Northeast Pennsylvania were collected in the fall of 2022 and tested via RT-qPCR for the presence of SARS-CoV-2. Fourteen ticks were amplified with late quantification cycles (Cq) using primers from two nucleocapsid genes (N1 and N2) via TaqMan assays. Three of these samples were amplified on a SYBR green assay during secondary testing. However, melt curve and gel electrophoresis analysis verified negative results for these three samples. Genetic sequencing was performed on one of the three samples to look for potential cross-reactions causing the amplification observed. However, no significant match was found in the NCBI database. Although all 449 blacklegged ticks were negative for SARS-CoV-2, I. scapularis should continue to be tested for COVID-19. If blacklegged ticks test positive for COVID-19 in the future, research should focus on determining the stability of SARS-CoV-2 with the tick vector and the potential for transmission through tick bites.

Limited detection of shared zoonotic pathogens in deer keds and blacklegged ticks co-parasitizing white-tailed deer in the eastern United States

Deer keds, such as Lipoptena cervi Linnaeus (Diptera: Hippoboscidae), are blood-feeding flies from which several human and animal pathogens have been detected, including Borrelia burgdorferi sensu lato Johnson (Spirochaetales: Borreliaceae), the causative agent of Lyme disease. Cervids (Artiodactyla: Cervidae), which are the primary hosts of deer keds, are not natural reservoirs of B. burgdorferi sl, and it has been suggested that deer keds may acquire bacterial pathogens via co-feeding near infected ticks. We screened L. cervi (n = 306) and Ixodes scapularis Say (Ixodida: Ixodidae) (n = 315) collected from 38 white-tailed deer in Pennsylvania for the family Anaplasmataceae, Bartonella spp. (Hyphomicrobiales: Bartonellaceae), Borrelia spp., and Rickettsia spp. (Rickettsiales: Rickettsiaceae). Limited similarity in the bacterial DNA detected between these ectoparasites per host suggested that co-feeding may not be a mechanism by which deer keds acquire these bacteria. The feeding biology and life history of deer keds may impact the observed results, as could the season when specimens were collected. We separately screened L. cervi (n = 410), L. mazamae Róndani (n = 13), L. depressa Say (n = 10), and Neolipoptena ferrisi Bequaert (n = 14) collections from locations within the United States and Canada for the same pathogens. These results highlight the need to further study deer ked-host and deer ked-tick relationships.

Artificial infestation of white-tailed deer with ticks (Acari: Ixodidae) to study tick-host interactions

White-tailed deer (Odocoileus virginianus) are a main host for the adult life stages of tick species of medical and veterinary importance. Since white-tailed deer play a vital role in tick ecology, research has been conducted to understand this tick-host relationship. To date, research involving captive white-tailed deer and artificial infestation of these animals with ticks has focused on host suitability, the role of white-tailed deer in tick-borne diseases, and anti-tick vaccine research. The methodology reported for these studies was at times not descriptive and inconsistent regarding how and what region of the white-tailed deer was infested with ticks. Here, we propose a standardized method to artificially infest captive white-tailed deer with ticks for research purposes. The protocol describes a method proven effective to experimentally infest captive white-tailed deer with blacklegged ticks (Ixodes scapularis) to study tick-host interactions. The methods can be reliably transferred for experimental infestation of white-tailed deer by other multi-host and one-host tick species.

All for One Health and One Health for All: Considerations for Successful Citizen Science Projects Conducting Vector Surveillance from Animal Hosts

Many vector-borne diseases that affect humans are zoonotic, often involving some animal host amplifying the pathogen and infecting an arthropod vector, followed by pathogen spillover into the human population via the bite of the infected vector. As urbanization, globalization, travel, and trade continue to increase, so does the risk posed by vector-borne diseases and spillover events. With the introduction of new vectors and potential pathogens as well as range expansions of native vectors, it is vital to conduct vector and vector-borne disease surveillance. Traditional surveillance methods can be time-consuming and labor-intensive, especially when surveillance involves sampling from animals. In order to monitor for potential vector-borne disease threats, researchers have turned to the public to help with data collection. To address vector-borne disease and animal conservation needs, we conducted a literature review of studies from the United States and Canada utilizing citizen science efforts to collect arthropods of public health and veterinary interest from animals. We identified common stakeholder groups, the types of surveillance that are common with each group, and the literature gaps on understudied vectors and populations. From this review, we synthesized considerations for future research projects involving citizen scientist collection of arthropods that affect humans and animals.