Rickettsia tillamookensis (Rickettsiales: Rickettsiaceae) in Ixodes scapularis (Acari: Ixodidae) in Oklahoma.

Some of the most prevalent arthropod-borne pathogens impacting humans in the United States are transmitted by Ixodes ticks. However, little is known regarding the Rickettsia species that inhabit Ixodes scapularis in the United States. The aim of this study was to screen adult I. scapularis collected in central Oklahoma over an 8-yr period for the presence of tick-borne rickettsial pathogens or potential pathogens. During 2014-2021, 112 adult specimens of I. scapularis were collected from central Oklahoma. Amplicons for Rickettsia spp. were amplified from 53 (47.3%) of the samples. Of the positive ticks, 42 (79.2%) amplicon-positive Rickettsia samples were 100% identical to Rickettsia buchneri, 10 (18.9%) were 100% identical to R. tillamookensis strain Tillamook 23, and 1 (1.9%) specimen showed high identity for Rickettsia amblyommatis. This study highlights the importance of considering Rickettsia-specific assays when assessing Ixodes species ticks for potential pathogens.

Factors influencing abundance of 3 tick species across a gradient of urban development intensity in the US Great Plains.

Urbanization alters abiotic conditions, vegetation, and wildlife populations in ways that affect tick abundance and tick-borne disease prevalence. Likely due to such changes, tick abundance has increased in many US urban areas. Despite growing public health importance of tick-borne diseases, little is known about how ticks are influenced by urbanization in North America, especially in the central United States where several pathogens occur at or near their highest incidences. To identify factors influencing tick abundance across a gradient of urbanization intensity, we used CO2 traps and flagging to sample ticks at 16 parks across Oklahoma City, Oklahoma, USA over 2 yr, conducted vegetation surveys, and used trail cameras to estimate a deer abundance index. Our results indicate there is a risk of encountering ticks across the entire urbanization gradient from exurban areas to the urban core, although some species (Dermacentor variabilis (Say)) appear less-common in heavily-urbanized areas. Vegetation variables were also associated with tick abundance. For example, Amblyomma maculatum Koch decreased with increasing woody plant and leaf litter cover, and there was a weak positive relationship between D. variabilis abundance and cover of understory eastern redcedar (Juniperus virginiana L.), indicating this native encroaching tree may increase tick populations in urban areas of the Great Plains. The deer abundance index was positively correlated with A. maculatum and D. variabilis abundance but unrelated to A. americanum (L.) abundance. Public health officials and land managers can use such information about parks/greenspaces and their surroundings to focus public education and land management efforts designed to reduce tick-borne disease prevalence.

Ecological Interactions of Predatory Mites, Cheyletus eruditus (Schrank) (Trombidiformes: Cheyletidae) and Cheyletus malaccensis Oudemans, and Prey, Liposcelis decolor (Pearman) (Psocodea: Liposcelididae), under Different Thermo-Hygrometric Regimes.

Predator-prey interactions are linked through trophic relationships, and individual population dynamics are a function of multiple interactions among many ecological factors. The present study considered the efficacy of the predatory mites Cheyletus eruditus (Schrank) (Trombidiformes: Cheyletidae) and Cheyletus malaccensis Oudemans to manage Liposcelis decolor (Pearman) (Psocodea: Liposcelididae). Prey population suppression and progeny replacement efficiency of the predators were assessed under different predator-prey ratios (0:20, 1:20, 2:20, 4:20, and 10:20), temperatures (20, 24, 28, and 32 °C), and relative humidities (RH) (63, 75, and 85%) over 40 days under laboratory conditions of 0:24 (L:D) photoperiod. Suppression of L. decolor population when C. eruditus-related predator-to-prey ratios of 1:20, 2:20, 4:20, and 10:20 were used was ~61.7, 79.7, 85.1, and 87.5%, respectively, relative to the Control ratio (0:20). In the case of C. malaccensis, suppression of 70, 82.1, 92.9, and 96.5%, respectively, was achieved. Although the low 63% RH limited efficacy of these cheyletid mites, both predatory mites caused pest population suppression of ~67.1-97.2% and increased their progeny by ~96.7-844.4% fold for the predator-prey ratios of 1:20, 2:20, 4:20, and 10:20, temperatures of 20, 24, 28, and 32 °C, and RH levels of 63, 75, and 85%. The levels of psocid population suppression achieved indicate the potential of both predatory mites for psocid management.

Numerical responses of the predatory mites, Cheyletus eruditus (Trombidiformes: Cheyletidae) and Cheyletus malaccensis, to Liposcelis decolor (Psocodea: Liposcelididae).

Predatory mites display diverse ecological mechanisms to suppress pest population density below certain thresholds known to cause economic loss. The current study explored the numerical responses of the predatory mites, Cheyletus eruditus (Schrank) (Trombidiformes: Cheyletidae) and Cheyletus malaccensis Oudemans, to Liposcelis decolor (Pearman) (Psocodea: Liposcelididae). The numerical responses of these 2 cheyletid mites to nymphs, adult males, and adult females of L. decolor were determined under laboratory conditions at 24 ± 1 °C, 85 ± 5 RH, and 0:24 (L:D) photoperiod. Oviposition rate, oviposition efficiency, and efficiency of conversion of ingested (ECI) food resources were the key numerical response parameters assessed. The present study revealed a general trend of a strong negative and positive correlation between oviposition rates and increase in prey densities (number of prey per 16.98 cm2) for C. eruditus and C. malaccensis, respectively. The oviposition efficiency was mostly similar for both predatory mites and was inversely related to prey density. Generally, ECI (%) decreased considerably with increasing prey density across different prey types for both predators, however, C. malaccensis was more efficient than C. eruditus in utilizing prey biomass. Given the relatively weak numerical responses, we recommended further assessment of these predatory mites before recommending their use for managing stored-product insect pests in the United States.

Effects of woody plant encroachment by eastern redcedar on mosquito communities in Oklahoma.

Woody plant encroachment into grasslands is occurring worldwide, affecting ecosystems in ways that likely influence mosquito-borne disease transmission. In the U.S. Great Plains, encroachment by eastern redcedar (Juniperus virginiana) (ERC) may be expanding conducive habitat for mosquitoes and their hosts, but few studies have evaluated associations between ERC encroachment and West Nile virus (WNV). To test the hypotheses that mosquito abundance and WNV-infected mosquitoes increase with increasing ERC cover, we collected mosquitoes in 32 sites in Oklahoma reflecting various ERC encroachment stages. We found support for our first hypothesis, as mean abundance of Aedes albopictus increased significantly with ERC cover. However, Psorophora columbiae and Anopheles quadrimaculatus abundance decreased with increasing ERC. There was no significant association with ERC for other mosquito species. We could not test our second hypothesis due to low WNV prevalence, but the only detected WNV-infected pool of mosquitoes (Cx. tarsalis) was collected in ERC. Our results suggest ERC encroachment increases abundance of at least one medically important mosquito species, but further research is needed to clarify how encroachment affects ecology of the entire WNV disease system through changes to vector and host communities, vector-host interactions, and thus disease transmission and prevalence. Understanding relationships between woody plant encroachment and the nidus of infection for mosquito-borne diseases will be crucial for targeting public health efforts, including land management activities that limit and/or eradicate woody plant encroachment, particularly in areas with high levels of disease risk.

Prevalence of selected pathogens in ectoparasites from free-roaming domestic cats in the southern Great Plains of the United States.

Rickettsia sp. and Bartonella sp. were detected in ectoparasites of free-roaming domestic cats (Felis catus) from a trap-neuter-release program in central Oklahoma during January and February 2020. We used polymerase chain reaction and sequencing to identify fleas containing DNA of five different pathogens: Rickettsia felis (84%), 'Candidatus R. andeanae' (8%), Bartonella henselae (32%), Bartonella clarridgeiae (36%), and Bartonella sp. (8%). Co-infections with R. felis with three Bartonella species were identified. One tick was positive for R. felis, one flea was positive for 'Candidatus R. andeanae' and one ear mite was positive for a Bartonella species. These results highlight the need for more focus on free-roaming domestic cats and their ectoparasites in the Great Plains region.

Use of an exclusion assay to detect novel rickettsiae in field collected Amblyomma americanum.

In the south-central United States, several tick-borne diseases (TbDs) occur at or near their highest levels of incidence of anywhere in the U.S. The diversity of Rickettsia species found in Amblyomma americanum continues to be under-characterized in this region and throughout the U.S. and Canada where this tick species is expanding. One reason for this lack of knowledge about Rickettsia diversity is the high prevalence of the endosymbiont Rickettsia amblyommatis that obscures detection of other bacteria in this genus. Focusing on unknown rickettsial agents, we used a recently described R. amblyommatis exclusion assay to screen 1909 A. americanum collected in Oklahoma City, Oklahoma, which resulted in eight ticks that had unique rickettsial sequences. Through the process of characterizing primary and secondary rickettsiae, we identified ticks primarily infected with Rickettsia rhipicephali and a Rickettsia species (2019-CO-FNY) previously linked with a canine rickettsiosis case in Tulsa, Oklahoma. We also identified a Rickettsia agent that was 97% identical with an endosymbiont of Amblyomma tonelliae and which aligned with archaic rickettsial species. Through this study, we further demonstrate the usefulness of this exclusion assay for rapid screening in large cohort A. americanum studies to identify a small number of ticks that contain poorly described and previously undocumented rickettsiae.

Seasonality of Ticks and Prevalence of Rickettsiae Species in Dermacentor variabilis and Amblyomma maculatum Across Oklahoma Pastures.

Tick-borne diseases are an increasing concern for people and companion animals in the United States, but there is a need for continued vigilance regarding livestock in pasture systems. The south-central United States has some of the highest incidences of tick-borne diseases, and there is a need to re-examine the ecology of tick vectors in relation to pasture systems and livestock. The objective of this study was to establish a baseline of seasonal activity for tick species in diverse regional Oklahoma pastures and screen for important pathogens in Dermacentor variabilis (Say) and Amblyomma maculatum Koch group that may impact livestock and human health. Between 2015 and 2017, transects in five pastures across Oklahoma were visited each month. DNA extracted from adult D. variabilis and A. maculatum group was tested for the presence of bacterial pathogens. We found that tick communities in pastures across Oklahoma differ by season, abundance, and bacterial presence and prevalence. The peak abundance of Amblyomma americanum (L.) adults and nymphs occurred a month earlier over the 2 yr of the study compared with historical studies in the same regions. Additionally, we observed notable differences in peak activity between A. americanum adults and nymphs collected in pastures in central Oklahoma (April) versus pastures in northern part of the state (May). We detected Rickettsia parkeri, R. bellii, and Anaplasma sp. DNA in D. variabilis from pastures across the state. These results potentially have important ramifications for human and livestock risk of encountering infected ticks in pastures across the southern Great Plains.

Effect of Urbanization on Presence, Abundance, and Coinfection of Bacteria and Protozoa in Ticks in the US Great Plains.

Urbanization alters components of natural ecosystems which can affect tick abundance and tick-borne disease prevalence. Likely due to these changes, tick-borne pathogen prevalence has increased in many U.S. urban areas. Despite the growing public health importance of tick-borne diseases, little is known about how they are influenced by urbanization in North America, especially in the central U.S. where several pathogens occur at or near their highest levels of incidence nationally. To determine whether urban development influences tick infection with bacteria and protozoa, we collected ticks at 16 parks across a gradient of urbanization intensity in Oklahoma City, Oklahoma, USA and tested them using a variety of PCR assays. Adult ticks tested positive for Rickettsia parkeri, R. amblyommatis, R. rhiphicephali, 'Candidatus R. andeanae', Ehrlichia chaffeensis, E. ewingii, Panola Mountain Ehrlichia, 'Borrelia lonestari', Theileria cervi, Babesia spp. Coco, and Cytauxzoon felis. These results indicate the presence of a high diversity of tick-borne bacteria and protozoa across an expanding urban area in the U.S. Great Plains. Although there appeared to be some risk of encountering tick-borne microorganisms across the entire urbanization gradient, E. chaffeensis, E. ewingii, and T. cervi-infected ticks and microbe diversity decreased with increasing urbanization intensity. We identified a low rate of coinfection between different microorganisms, with coinfected ticks mainly collected from sites in the least-urbanized areas. This study suggests the need for awareness of tick-borne disease risk throughout urban areas in the central U.S., and highlights a need for studies of tick host habitat use and movement in cities.

An elution independent collection device (EICD) for rapid collection of Anaplasma marginale DNA from blood samples.

Currently utilized molecular detection methods are based mainly on nucleic acid extraction, amplification, and detection procedures that may require costly equipment, numerous reagents, and highly trained personnel. These requirements make diagnostic tests expensive, time-consuming, and not suitable for point-of-care applications. There is an increasing demand for simple, low-cost portable technologies. To overcome these challenges, a paper-based elution independent collection device (EICD) was designed to collect microorganisms and recover nucleic acids for molecular biology applications with minimal steps. In this study, we demonstrate a simpler Anaplasma marginale detection that uses an EICD for nucleic acid collection combined with recombinase polymerase amplification (RPA), and a lateral flow dipstick for detection of the specified target. A pre-lysis blood treatment was optimized that uses Triton X-100 lysis buffer and bovine serum album in wash buffer. Blood samples were incubated for 5 min at room temperature and run through the EICD. Four 1-mm diameter discs excised from EICD were used as template in basic RPA and lateral flow (nfo) (endonuclease IV) RPA assays. Each disc of soluble central membrane (SCM) carried circa 0.249 pg/µl of Anaplasma DNA. The percentage of nucleic acid recoverable from the SCM ranged between 60% - 70%. Blood samples infected with A. marginale were treated with Triton X-100 pre-lysis protocol. All samples tested positive by PCR and RPA methods. EICD-driven collection of blood samples is a practical method successfully adapted to detect Anaplasma spp. or blood-borne pathogen DNA and has potential for point-of-care detection in resource-limited settings.

Invasive Plants as Foci of Mosquito-Borne Pathogens: Red Cedar in the Southern Great Plains of the USA.

West Nile virus (WNV) is the most significant mosquito-borne disease affecting humans in the United States. Eastern redcedar (ERC) is a native encroaching plant in the southern Great Plains that greatly alters abiotic conditions and bird and mosquito populations. This study tested the hypotheses that mosquito communities and their likelihood of WNV infection differ between ERC and other habitats in the southern Great Plains of the United States. We found support for our first hypothesis, with significantly more Culex tarsalis and Culex erraticus in ERC than deciduous and grass habitats. Mosquito communities in Central Oklahoma were more diverse (21 species) than western Oklahoma (11 species) but this difference was not associated with vegetation. Our second hypothesis was also supported, with significantly more WNV-infected Culex from ERC in both regions, as was our third hypothesis, with significantly more Culex tarsalis and Culex pipiens collected in ERC than other habitats in urban areas. The connection of mosquito-borne disease with invasive plants suggests that land management initiatives can affect human health and should be considered in light of public health impact. Evidence from other vector-borne disease suggests invasive plants, both in the Great Plains and globally, may facilitate the transmission of vector-borne pathogens.

Recombinase polymerase amplification (RPA) with lateral flow detection for three Anaplasma species of importance to livestock health.

Anaplasma marginale, A. ovis, and A. phagocytophilum are the causative agents of bovine anaplasmosis, ovine anaplasmosis, and granulocytic anaplasmosis, respectively. The gold standard for diagnosis of post-acute and long-term persistent infections is the serological cELISA, which does not discriminate between Anaplasma species and requires highly equipped laboratories and trained personnel. This study addresses the development of a rapid, isothermal, sensitive, species-specific RPA assays to detect three Anaplasma species in blood and cELISA A. marginale-positive serum samples. Three RPA primer and probe sets were designed targeting msp4 genes of each Anaplasma species and the internal control (GAPDH gene) for each assay. The limit of detection of gel-based or RPA-basic assays is 8.99 × 104 copies/µl = A. marginale, 5.04 × 106 copies/µl = A. ovis, and 4.58 × 103 copies/µl = A. phagocytophilum, and for each multiplex lateral flow or RPA-nfo assays is 8.99 × 103 copies/µl of A. marginale, 5.04 × 103 copies/µl of A. ovis, 4.58 × 103 copies/µl of A. phagocytophilum, and 5.51 × 103 copies/µl of internal control (GAPDH). Although none of the 80 blood samples collected from Oklahoma cattle were positive, the RPA-nfo assays detected all A. marginale cattle blood samples with varying prevalence rates of infection, 83% of the 24 cELISA A. marginale-positive serum samples, and all A. phagocytophilum cell culture samples. Overall, although early detection of three Anaplasma species was not specifically addressed, the described RPA technique represents an improvement for detection of three Anaplasma in regions where access to laboratory equipment is limited.

College Students' Knowledge of Ticks in Oklahoma: Assessment and Insights.

Ticks (Arachnida: Acari) are common in Oklahoma and may transmit tick-borne diseases (TBDs) to people. Due to the difficulty in reducing tick populations, awareness of tick bite prevention, proper tick removal, and knowledge of when to seek medical treatment are critical. However, outreach and extension programs are hampered by a lack of knowledge of what community members know about ticks. To address this limitation, we surveyed college students enrolled in three non-major Entomology courses at Oklahoma State University in 2018. Of the 483 students invited to take a survey, 224 (46.4%) students took both surveys. Pre-survey responses indicated lower levels of knowledge of tick biology compared to post-survey responses. For both pre- and post-survey respondents, "ticks can jump" and "ticks reside up in trees" received the fewest correct responses. A majority of survey respondents considered Lyme disease to be the predominant TBD in Oklahoma, although it is not established in Oklahoma. Supplemental education overcame these knowledge gaps, with the exception of knowledge of Lyme disease which was still considered to be the predominant TBD in the post-survey. Our results can be used to develop assessment tools to improve extension programs and enhance protection from TBDs.

Effects of Dehumidification on the Survivorship of Four Psocid Species.

Psocids are damaging stored-product pests. In this study, eggs and early-instar nymphs, adults, and all life stages of Liposcelis entomophila, L. decolor, L. bostrychophila, and L. paeta were subjected to 43, 50, or 75% (Control) relative humidity (RH) for 2, 4, 6, 8, 10, 12, 14, or 16 d at 30.0°C. All adults of these species died within 8 d at both 43 and 50% RH, except for L. bostrychophila, which required 12 d at 50% RH for 100% mortality to occur. For all life stages and eggs and early-instar nymphs, maximum survival times (times to 100% mortality) at 43 or 50% RH for L. entomophila, L. decolor, L. bostrychophila, and L. paeta, were 8 and 10 d, 8 and 12 d, 12 and 14 d, and 12 and 16 d, respectively. During this study, numbers of nymphs and adults of all species 14 d after the RH treatments increased within the 75% RH Control arenas. Different species and life stages responded differently to 43 and 50% RH, as time to kill all stages of the four psocid species was 8-12 and 10-16 d, respectively. Results indicate that using a specific RH environment may be effective in psocid management.

Distribution of Culex coronator in the USA.

In 1920, Culex coronator was reported from San Benito, Texas, and later in Arizona, New Mexico, and Oklahoma. In 2005, this species was reported to be spreading across the southeastern USA. Now reported in 14 states, it has been found as far north as northern Oklahoma; Memphis, TN; and Suffolk, VA. The public health significance of Cx. coronator is not firmly established, even though it has been implicated as a potential vector of several arboviral diseases. This study aims to document additional Cx. coronator county-level records, to provide information about its continued expansion across the southern USA, and to provide a short research update into its vector potential. Data acquired through multistate collaborations and author collections resulted in 146 new county records from Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, and Texas. No new county records were presented for Arizona, New Mexico, Tennessee, or Virginia, which had previously reported this species. With these new data, this species has been documented in 386 counties in 14 states of the continental USA.

Invasive woody plants as foci of tick-borne pathogens: eastern redcedar in the southern Great Plains.

Habitat preference and usage by disease vectors are directly correlated with landscapes often undergoing anthropogenic environmental change. A predominant type of land use change occurring in the United States is the expansion of native and non-native woody plant species in grasslands, but little is known regarding the impact of this expansion on regional vector-borne disease transmission. In this study, we focused on the impact of expanding eastern redcedar (Juniperus virginiana; ERC) and tested two hypotheses involving relationships between habitat preferences of adult tick species in rural habitats in central Oklahoma. Using CO2 traps, we collected ticks from two densities of ERC and grassland and screened adult ticks for the presence of pathogen DNA. We found support for our first hypothesis with significantly more Amblyomma americanum (Linnaeus) and Dermacentor variabilis (Say) collected in ERC habitats than in grassland. Our second hypothesis was also supported, as Ehrlichia- and Rickettsia-infected A. americanum were significantly more likely to be collected from ERC habitats than grassland. As the first evidence that links woody plant encroachment with important tick-borne pathogens in the continental United States, these results have important ramifications involving human and companion animal risk for encountering pathogen-infected ticks in the southern Great Plains.

Mosquito-borne parasites in the Great Plains: searching for vectors of nematodes and avian malaria parasites.

Vector-borne diseases in the United States have recently increased as a result of the changing nature of vectors, hosts, reservoirs, parasite/pathogens, and the ecological and environmental conditions. While most focus has been on mosquito-borne pathogens affecting humans, little is known regarding parasites of companion animal, livestock and wildlife and their potential mosquito hosts in the United States. This study assessed the prevalence of mature infections of Dirofilaria immitis and avian malaria parasites (Haemosporida) within urban mosquito (Diptera, Culicidae) communities in Oklahoma. 2,620 pools consisting of 12,686 mosquitoes from 13 species collected over two summers were tested for the presence of filarioid and haemosporidian DNA. Dirofilaria immitis-infected mosquitoes were detected only in Aedes albopictus (MIR=0.18-0.22) and Culex pipiens complex (MIR=0.12) collected in cities in central and southern Oklahoma. Two other filarioid nematode species with 91-92% similarity with Onchocerca spp. and Mansonella spp. were also detected. Haemosporidian DNA was detected in 13 mosquito pools (0.9% of pools tested) from seven mosquito species out of 13 species tested. Plasmodium DNA in four species (Cx. coronator, Cx. pipiens complex, Cx. tarsalis, and Psorophora columbiae) had high homology with published sequences of avian Plasmodium species while DNA in four other species (Cx. nigripalpus, Ps. columbiae, Anopheles quadrimaculatus, and An. punctipennis) were closely related to Plasmodium species from deer. One pool of Cx. tarsalis was positive with a 100% sequence identity of Haemoproteus sacharovi. This study provides a baseline concerning the diversity of parasites in different mosquito species present in the southern Great Plains. These studies provide important information for understanding the factors of transmission involving the mosquito community, potential hosts, and different mosquito-borne parasites in this important region involved in livestock management and wildlife conservation.

Landscape and Anthropogenic Factors Associated with Adult Aedes aegypti and Aedes albopictus in Small Cities in the Southern Great Plains.

As mosquito-borne diseases are a growing human health concern in the United States, the distribution and potential arbovirus risk from container-breeding Aedes mosquitoes is understudied in the southern Great Plains. The aim of the study was to assess landscape and anthropogenic factors associated with encountering adult container-breeding mosquitoes in small cities in southern Oklahoma. Collections were carried out over a 10 week period from June to August 2017 along two geographical transects, each consisting of three cities, equally distant from the Red River/Texas border. Mosquitoes were collected weekly using two trap types along with data for 13 landscape, vegetation, and anthropogenic variables. After five rounds of collection, 6628 female mosquitoes were collected over 2110 trap-nights involving 242 commercial or residential sites in six cities. Of the mosquitoes collected, 80% consisted of container-breeding species: Aedes albopictus (72%), Culex pipiens complex (16%) and Aedes aegypti (8%). Regionally, Aedes aegypti was more likely present in cities closest to the Texas border while Ae. albopictus was spread throughout the region. In general, Ae. aegypti and Ae. albopictus were significantly more present in sites featuring no or low vegetation and residential sites. Variables associated with Ae. albopictus presence and abundance varied between cities and highlighted the urban nature of the species. The study highlighted the distribution of Ae. aegypti geographically and within the urban context, indicated potential habitat preferences of container-breeding mosquito species in small towns, and demonstrated the usefulness of Gravid Aedes traps (GAT) traps for monitoring Aedes populations in urban habitats in small cities.

Waveforms From Stylet Probing of the Mosquito Aedes aegypti (Diptera: Culicidae) Measured by AC-DC Electropenetrography.

Electropenetrography (EPG) has been used for many years to visualize unseen stylet probing behaviors of plant-feeding piercing-sucking insects, primarily hemipterans. Yet, EPG has not been extensively used with blood-feeding insects. In this study, an AC-DC electropenetrograph with variable input resistors (Ri), i.e., amplifier sensitivities, was used to construct a waveform library for the mosquito arbovirus vector, Aedes aegypti (Linneaus), while feeding on human hands. EPG waveforms representing feeding activities were: 1) electrically characterized, 2) defined by visual observation of biological activities, 3) analyzed for differences in appearance by Ri level and type of applied signal (AC or DC), and 4) quantified. Electrical origins of waveforms were identified from five different Ri levels and AC versus DC. Mosquitoes produced short stylet probes ('bites') that typically contained five waveform families. Behaviors occurred in the following order: surface salivation (waveform family J), stylet penetration through the outer skin (K), penetration of deeper tissues and location of blood vessels/pathway activities (L), active ingestion with engorgement (M), and an unknown behavior that terminated the probe (N). Only K, L, and M were performed by every insect. A kinetogram of conditional probabilities for waveform performance demonstrated plasticity among individuals in L and M, which were alternated. Now that EPG waveforms for mosquito feeding have been defined, EPG can be used as a tool for improved biological understanding of mosquito-borne diseases.

Rickettsia parkeri and Candidatus Rickettsia andeanae in Amblyomma maculatum Group Ticks.

We determined prevalence of Rickettsia spp. in 172 ticks of the Amblyomma maculatum group collected from 16 urban sites in Oklahoma City, Oklahoma, USA, during 2017 and 2018. Most ticks (59.3%) were collected from 1 site; 4 (2.3%) were infected with Rickettsia parkeri and 118 (68.6%) with Candidatus Rickettsia andeanae.