scholarly journals Ticks Home in on Body Heat: A New Understanding of Ectoparasite Host-Seeking and Repellent Action

2019 ◽  
Author(s):  
Ann L. Carr ◽  
Vincent L. Salgado
Keyword(s):  
High Sensitivity ◽  
Radiant Heat ◽  
Dermacentor Variabilis ◽  
Host Finding ◽  
Amblyomma Americanum ◽  
Innovative Strategies ◽  
Insect Repellents ◽  
Host Seeking ◽  
Haller's Organ ◽  
Seeking Behavior

AbstractTicks are second only to mosquitoes as vectors of disease to humans and animals. Commercial insect repellents reduce or prevent potentially infectious tick bites by disrupting tick host-seeking behavior. Tick host-seeking is mainly ascribed to the Haller’s organ, a complex sensory structure on the tick foreleg that detects odors, carbon dioxide and heat 4–7, but these host-seeking mechanisms and the mechanism of their disruption by repellents are not well understood1,2. There is anecdotal evidence that ticks and other ectoparasites are attracted to heat, but it has never been demonstrated that they use radiant heat to detect hosts at a distance. In fact, previous attempts to do this have concluded that radiant heat is not used by ticks. Here we show that Amblyomma americanum and Dermacentor variabilis ticks can sense and home in on a human from several meters away, guided by radiant heat sensed by the Haller’s organ, and specifically the capsule, a covered spherical pit organ. An aperture in the capsule cover confers directionality and highly reflective interior surfaces of the capsule provide high sensitivity. Low concentrations of the insect repellents DEET, picaridin, 2-undecanone, citronellal and nootkatone eliminate thermotaxis without affecting olfactory-stimulated host-seeking behavior. Our results demonstrate that the tick Haller’s organ capsule is a radiant heat sensor used in host-finding and that repellents disrupt this sense at concentrations that do not disrupt olfaction. We anticipate this discovery to significantly aid insect repellent research and development of innovative strategies for protection against ectoparasites and vector-borne disease.

Electrophysiological and behavioral responses of Bradysia odoriphaga (Diptera: Sciaridae) to volatiles from its Host Plant, Chinese Chives (Allium tuberosum Rottler ex Spreng)

2019 ◽  
Vol 112 (4) ◽  
pp. 1638-1644 ◽  
Author(s):  
Yuting Yang ◽  
Qi Su ◽  
Linlin Shi ◽  
Gong Chen ◽  
Yang Zeng ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Behavioral Responses ◽  
Host Finding ◽  
Gas Chromatography Mass Spectrometry ◽  
Diallyl Disulfide ◽  
Allium Tuberosum ◽  
Host Seeking ◽  
Seeking Behavior ◽  
Chinese Chives

Abstract Bradysia odoriphaga Yang et Zhang is a serious belowground pest of Chinese chives (Allium tuberosum). Our previous studies have indicated that B. odoriphaga females prefer to oviposit near the roots of Chinese chives rather than the roots of other plants, and that the performance (longevity and fecundity) of B. odoriphaga offspring was better on Chinese chives than on Lettuce (var. ramosa Hort.), Onion (Allium cepa) and Potato (Solanum tuberosum) but little is known about how the volatiles released by Chinese chives affect the host-finding and oviposition behaviors of B. odoriphaga. Here, we used gas chromatography-mass spectrometry and determined that Chinese chives releases the following volatiles: methyl allyl disulfide, β-myrcene, cis-ocimene, diallyl disulfide, nonane, n-dodecane, n-tetradecane, and n-hexadecane; quantities released were highest for methyl allyl disulfide and diallyl disulfide. In addition to eliciting strong responses in females in electroantennography assays, the latter two sulfur compounds and their mixtures attracted females in Y-tube olfactometer assays. The addition of methyl allyl disulfide, diallyl disulfide, or a mixture of the two compounds at a 1:5 ratio to chive plants increased oviposition when compared to control plants. These results indicate that methyl allyl disulfide and diallyl disulfide, either alone or in combination, influence the host-seeking behavior of B. odoriphaga.

scholarly journals The oviposition cue indole inhibits animal-host attraction in Aedes aegypti mosquitoes

2021 ◽  
Author(s):  
Amir Dekel ◽  
Evyatar Sar-Shalom ◽  
Esther Yakir ◽  
Jonathan Daniel Bohbot
Keyword(s):  
Aedes Aegypti ◽  
Long Range ◽  
Disease Transmission ◽  
Odorant Receptor ◽  
Host Attraction ◽  
Animal Host ◽  
Insect Repellents ◽  
Host Seeking ◽  
Spatial Repellent ◽  
Seeking Behavior

Abstract Mosquitoes represent a major source of disease transmission and possess the uncanny ability to locate suitable animal-hosts, a feature mediated by their exquisite olfactory system. Insect repellents such as N,N-Diethyl-meta-toluamide, also called DEET, have been shown to activate and inhibit mosquito odorant receptors resulting in behavioral modulation. This and other repellents available for personal protection against mosquitoes are topically applied on the skin and operate at short range. In our search for potential long-range odorant repellents, we have hypothesized that the shared chemical similarities between indole and DEET, may confer the former the ability to block odorant receptor function and inhibit human-host attraction. Using the two-electrode voltage clamp of Xenopus laevis oocytes as a pharmacological platform, we provide evidence that indole inhibits the Aedes aegypti (R)-1-octen-3-ol receptor OR8, a receptor involved in the decision of female mosquitoes to identify human hosts. Coincidentally, we also show that indole inhibits the animal-host seeking behavior of female Aedes aegypti. Together, our findings suggests that indole may be a candidate spatial repellent for the long-range protection of humans against mosquito bites.

scholarly journals Surveillance of Host-Seeking Ticks in the Flint Hills Region (USA) and Associations with Environmental Determinants

Parasitologia ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 137-147
Author(s):  
Mark Spare ◽  
Gunavanthi D. Boorgula ◽  
Dan Thomson ◽  
Jianfa Bai ◽  
Doug Goodin ◽  
...  
Keyword(s):  
Gulf Coast ◽  
Ixodes Scapularis ◽  
Dermacentor Variabilis ◽  
Amblyomma Americanum ◽  
Flint Hills ◽  
Host Seeking ◽  
The Usa ◽  
Gulf Coast Tick ◽  
The Times ◽  
Dog Tick

Diversity and phenology of host-seeking ticks were studied in the Flint Hills region of the USA, which is a prominent region for raising beef cattle. Between a two-year period from 2015–2017, ticks were collected using the dragging method from 9 distant locations, 6 of which were studied seasonally and 3 continuously throughout the study period. Of the 10,055 ticks collected, 76.5% were the Lonestar tick (Amblyomma americanum), 14% were American dog tick (Dermacentor variabilis), and 9.1% were Gulf Coast tick (A. maculatum). The blacklegged tick, Ixodes scapularis were also found, albeit in low numbers. The host-seeking activity of all three predominant tick species peaked once during the late spring, summer months in the region. The phenology of all ticks was positively associated with accumulated temperature and photoperiod. Additionally, the Normalized Vegetation Difference Index (NDVI) was associated with A. americanum, and saturation deficit and relative humidity were negatively associated with D. variabilis and A. maculatum tick phenology, respectively. This finding is useful to predict the times during a year in which cattle are at higher risk for exposure to these ticks and associated pathogens.

scholarly journals Diversity and seasonality of host-seeking ticks in a periurban environment in the Central Midwest (USA)

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250272
Author(s):  
Ali Hroobi ◽  
Gunavanthi D. Boorgula ◽  
David Gordon ◽  
Jianfa Bai ◽  
Doug Goodin ◽  
...  
Keyword(s):  
United States ◽  
Tick Species ◽  
Ixodes Scapularis ◽  
Dermacentor Variabilis ◽  
Amblyomma Americanum ◽  
Late Spring ◽  
Molecular Methods ◽  
Activity Period ◽  
Life Stages ◽  
Host Seeking

Between March 2014 and February 2017, host-seeking ticks were collected during the late spring and summer months seasonally, and as well as continually through all seasons from several sites in a periurban environment in Pittsburg, Kansas, located in the Central Midwestern United States. All three post-emergent life-stages of Amblyomma americanum, and the adults of three other ticks viz. Dermacentor variabilis, A. maculatum, and Ixodes scapularis were collected using the flagging method, and were taxonomically identified using morphological and molecular methods. A total of 15946 ticks were collected from these sites. A vast majority of the ticks collected over the three-year study period was A. americanum (79.01%). The three other species collected included D. variabilis (13.10%), A. maculatum (7.15%), and Ixodes scapularis (0.73%). More female ticks of each species were collected throughout the study period from all sites, and a unimodal activity period was noted for all four species. The diversity, composition, and phenology of these medically significant tick species are discussed.

scholarly journals Homologs of Caenorhabditis elegans Chemosensory Genes Have Roles in Behavior and Chemotaxis in the Root-Knot Nematode Meloidogyne incognita

2019 ◽  
Vol 32 (7) ◽  
pp. 876-887 ◽  
Author(s):  
Tagginahalli N. Shivakumara ◽  
Tushar K. Dutta ◽  
Sonam Chaudhary ◽  
Stephan H. von Reuss ◽  
Valerie M. Williamson ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Meloidogyne Incognita ◽  
Functional Characterization ◽  
Host Finding ◽  
Host Recognition ◽  
Root Knot Nematode ◽  
Chemosensory Genes ◽  
Host Seeking ◽  
Seeking Behavior ◽  
Plant Nematode

Nematode chemosensation is a vital component of their host-seeking behavior. The globally important phytonematode Meloidogyne incognita perceives and responds (via sensory organs such as amphids and phasmids) differentially to various chemical cues emanating from the rhizosphere during the course of host finding. However, compared with the free-living worm Caenorhabditis elegans, the molecular intricacies behind the plant nematode chemotaxis are a yet-unexploited territory. In the present study, four putative chemosensory genes of M. incognita, namely, Mi-odr-1, Mi-odr-3, Mi-tax-2, and Mi-tax-4 were molecularly characterized. Mi-odr-1 mRNA was found to be expressed in the cell bodies of amphidial neurons and phasmids of M. incognita. Mi-odr-1, Mi-odr-3, Mi-tax-2, and Mi-tax-4 transcripts were highly expressed in early life stages of M. incognita, consistent with a role of these genes in host recognition. Functional characterization of Mi-odr-1, Mi-odr-3, Mi-tax-2, and Mi-tax-4 via RNA interference revealed behavioral defects in M. incognita and perturbed attraction to host roots in Pluronic gel medium. Knockdown of Mi-odr-1, Mi-odr-3, Mi-tax-2, and Mi-tax-4 resulted in defective chemotaxis of M. incognita to various volatile compounds (alcohol, ketone, aromatic compound, ester, thiazole, pyrazine), nonvolatiles of plant origin (carbohydrate, phytohormone, organic acid, amino acid, phenolic), and host root exudates in an agar-Pluronic gel–based assay plate. In addition, ascaroside-mediated signaling was impeded by downregulation of chemosensory genes. This new information that behavioral response in M. incognita is modulated by specific olfactory genes can be extended to understand chemotaxis in other nematodes.

Supercooling Points of Adult Dermacentor variabilis (Acari: Ixodidae) From a Population Near the Northern Distribution Limit

2020 ◽  
Author(s):  
Matthew E M Yunik ◽  
Neil B Chilton
Keyword(s):  
Cold Hardiness ◽  
Dermacentor Variabilis ◽  
Subzero Temperatures ◽  
Host Seeking ◽  
Short Period ◽  
Significant Difference ◽  
Northern Distribution ◽  
Dog Tick ◽  
Provincial Park ◽  
Established Population

Abstract The northern distributional limit of Dermacentor variabilis Say, the American dog tick, is expanding in Saskatchewan and Manitoba (western Canada). The ability of D. variabilis to continue to expand its range northwards will depend upon the ability of individuals within populations at the species distributional edge to withstand very low temperatures during winter. One component of cold hardiness is the supercooling point (SCP), the temperature below 0°C at which an individual freezes. In this study, the SCP was determined for 94 questing D. variabilis adults (44 females and 50 males) from an established population near Blackstrap Provincial Park in Saskatchewan. SCP values ranged from −18.2 to −6.7°C, with a median of −13.3°C. This suggests that host-seeking D. variabilis adults differ in their ability to survive exposure to subzero temperatures, for at least a short period of time, without freezing. The distribution of SCPs was bimodal, but there was no significant difference in SCP values between female and male ticks, and no relationship between SCP and tick body weight. It remains to be determined what factors contribute to the variation in SCP values among questing D. variabilis adults.

scholarly journals Influence of pyrethroïd-treated bed net on host seeking behavior of Anopheles gambiae s.s. carrying the kdr allele

PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0164518 ◽  
Author(s):  
Angélique Porciani ◽  
Malal Diop ◽  
Nicolas Moiroux ◽  
Tatiana Kadoke-Lambi ◽  
Anna Cohuet ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Bed Net ◽  
Anopheles Gambiae S.S ◽  
Host Seeking ◽  
Seeking Behavior

Synthetic Pyrethroid, Natural Product, and Entomopathogenic Fungal Acaricide Product Formulations for Sustained Early Season Suppression of Host-Seeking Ixodes scapularis (Acari: Ixodidae) and Amblyomma americanum Nymphs

2020 ◽  
Author(s):  
Terry L Schulze ◽  
Robert A Jordan
Keyword(s):  
Natural Product ◽  
Ixodes Scapularis ◽  
Tick Control ◽  
Amblyomma Americanum ◽  
Synthetic Pyrethroid ◽  
Activity Period ◽  
Synthetic Pyrethroids ◽  
Seasonal Activity ◽  
Early Season ◽  
Host Seeking

Abstract We compared the ability of product formulations representing a synthetic pyrethroid acaricide (Talstar P Professional Insecticide), a natural product-based acaricide (Essentria IC3), and an entomopathogenic fungal acaricide (Met52 EC Bioinsecticide) to suppress Ixodes scapularis Say and Amblyomma americanum (L.) nymphs when applied following USEPA approved manufacturers’ label recommendations for tick control using hand-pumped knapsack sprayers before the beginning of their seasonal activity period in the spring. We applied Met52 EC Bioinsecticide (11% Metarhizium anisopliae Strain F52) to five 100 m2 plots (10.6 ml AI/plot) in mid-April 2020. Two weeks later at the end of April 2020, we treated an additional five 100 m2 plots each with either Talstar P Professional Insecticide (7.9% bifenthrin @ 2.5 ml AI/plot) or Essentria IC3 (10% rosemary oil, 5% geraniol, and 2% peppermint oil @ 86.6 ml AI/plot). Weekly sampling of all plots through the end of June 2020 showed that both Met52 EC Bioinsecticide and Essentria IC3 failed to maintain a 90% suppression threshold for I. scapularis, compared to control plots, and required two additional applications over the course of the trial. In contrast, Talstar P Professional Insecticide suppressed 100% of I. scapularis nymphs and ≥96 and 100% of A. americanum nymphs and adults, respectively. Such pre-season applications of synthetic pyrethroids significantly reduce the early season acarological risk for exposure to host-seeking ticks as well as the frequency of acaricide applications.

Collaborating With Community Scientists Across Arkansas to Update Tick Distributions and Pathogen Prevalence of Spotted Fever Group Rickettsia and Ehrlichia

2021 ◽  
Author(s):  
Ashley P G Dowling ◽  
Sean G Young ◽  
Kelly Loftin
Keyword(s):  
Tick Species ◽  
Spotted Fever ◽  
Dermacentor Variabilis ◽  
Amblyomma Americanum ◽  
Spotted Fever Group ◽  
Primary Role ◽  
Prevalence Rates ◽  
Spotted Fever Group Rickettsia ◽  
Community Science ◽  
Tick Distributions

Abstract Tick-borne diseases (TBD) in humans have dramatically increased over recent years and although the bulk of cases are attributable to Lyme Disease in the Northeastern US, TBDs like spotted fever rickettsiosis and ehrlichiosis heavily impact other parts of the country, namely the mid-south. Understanding tick and pathogen distributions and prevalence traditionally requires active surveillance, which quickly becomes logistically and financially unrealistic as the geographic area of focus increases. We report on a community science effort to survey ticks across Arkansas to obtain updated data on tick distributions and prevalence of human tick-borne disease-causing pathogens in the most commonly encountered ticks. During a 20-mo period, Arkansans submitted 9,002 ticks from 71 of the 75 counties in the state. Amblyomma americanum was the most common tick species received, accounting for 76% of total tick submissions. Nearly 6,000 samples were screened for spotted fever group Rickettsia (SFGR) and Ehrlichia, resulting in general prevalence rates of 37.4 and 5.1%, respectively. In addition, 145 ticks (2.5%) were infected with both SFGR and Ehrlichia. Arkansas Department of Health reported 2,281 spotted fever and 380 ehrlichiosis cases during the same period as our tick collections. Since known SFGR vectors Dermacentor variabilis and Amblyomma maculatum were not the most common ticks submitted, nor did they have the highest prevalence rates of SFGR, it appears that other tick species play the primary role in infecting humans with SFGR. Our investigation demonstrated the utility of community science to efficiently and economically survey ticks and identify vector-borne disease risk in Arkansas.

scholarly journals Association of the invasive Haemaphysalis longicornis tick with vertebrate hosts, other native tick vectors, and tick-borne pathogens in New York City

2020 ◽  
Author(s):  
Danielle M. Tufts ◽  
Laura B. Goodman ◽  
Meghan C. Benedict ◽  
April D. Davis ◽  
Meredith C. VanAcker ◽  
...  
Keyword(s):  
United States ◽  
New York ◽  
Vector Potential ◽  
The United States ◽  
Dermacentor Variabilis ◽  
Amblyomma Americanum ◽  
Invasive Pest ◽  
Haemaphysalis Longicornis ◽  
Tick Vectors ◽  
Host Associations

AbstractHaemaphysalis longicornis, the Asian longhorned tick, is an invasive ixodid tick that has rapidly spread across the northeastern and southeastern regions of the United States since first reported in 2017. The emergence of H. longicornis presents a potential threat for livestock, wildlife, and human health as the host associations and vector potential of this invasive pest in the United States are poorly understood. Previous field data from the United States has shown that H. longicornis was not associated with natural populations of small mammals or birds, but they show a preference for medium sized mammals in laboratory experiments. Therefore, medium and large sized mammals were sampled on Staten Island, New York to determine H. longicornis host associations and vector potential for a range of human and veterinary pathogens. A total of 97 hosts were sampled and five species of tick (Amblyomma americanum, Dermacentor variabilis, H. longicornis, Ixodes scapularis, Ixodes cookei) were found feeding concurrently on these hosts. Haemaphysalis longicornis was found in the highest proportions compared to other native tick species on raccoons (55.4%), Virginia opossums (28.9%), and white-tailed deer (11.5%). Tissue, blood, and engorged larvae were tested for 17 different pathogens using a nanoscale PCR platform. Infection with five pathogens (Borrelia burgdorferi, Anaplasma phagocytophilum, Rickettsia spp., Mycoplasma haemocanis, and Bartonella spp.) was detected in host samples, but no pathogens were found in any larval samples. These results suggest that although large and medium sized mammals feed large numbers of H. longicornis ticks in the environment there is presently a low potential for H. longicornis to acquire pathogens from these wildlife hosts.HighlightsH. longicornis were sampled from seven genera of large and medium-sized mammalsRaccoons, opossums, and white-tailed deer fed a large proportion of H. longicornisH. longicornis did not acquire pathogens through co-feeding with native tick vectorsHost species were infected with a range of pathogens of human and veterinary concernHost-derived H. longicornis engorged larvae were not infected with any pathogens

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