Tick-borne Diseases In Humans Research Articles

Danger on the track? Tick densities near recreation infrastructures in forests

The risk of tick-borne disease in humans depends on the exposure to pathogen-infected ticks, which in turn is driven by local tick population densities, pathogen prevalence and human activity. Variation in tick densities and pathogen prevalence between green spaces differing in habitat characteristics, location and geography has been well documented. In contrast, variation within green spaces, although vital for management and prevention of disease risk, remains poorly understood. Studying this variation may lead to a better understanding of the drivers of small-scale tick distribution and reveal priority locations for tick management. We sampled ticks within green spaces at three location types representing different green space infrastructures and levels of human activity: (1) a structural element (e.g. bench); (2) the ecotone 40 m further along the adjacent trail and; (3) the interior of the associated forest stand, 20 m perpendicular to the trail, between (1) and (2). Drag sampling took place in 2018 and 2019 at 36 locations in 10 green spaces located in the Campine region of Flanders, Belgium. The density of questing nymphs (DON) was lowest at structural elements and slightly higher adjacent to trails. The highest tick densities were recorded in the forest interior. DON was higher in deciduous than in coniferous forests as well as in stands with a more developed shrub layer. This was true for all location types, as we observed a strong correlation of DON between location types within forest stands. This enables the prediction of DON within forest stands, thus enabling the prediction of DON near infrastructure based on the associated forest stand characteristics. Prevention and management efforts should be focused on infrastructure in or adjacent to deciduous, structure-rich forest stands, although large variation in DON at all location types indicates overall, factual risk while using green space infrastructure.

Genomic Profiling for Piroplasms in Feeding Ixodid Ticks in the Eastern Cape, South Africa.

Importation of tick-infected animals and the uncontrollable migration of birds and wild animals across borders can lead to geographical expansion and redistribution of ticks and pathogen vectors, thus leading to the emergence and re-emergence of tick-borne diseases in humans and animals. Comparatively, little is known about the occurrence of piroplasms in ixodid ticks in the Eastern Cape, South Africa, thus necessitating this study, which is aimed at detecting piroplasms (Theileria and Babesia) from feeding tick samples collected from cattle, sheep, and goats in selected sites in the Eastern Cape, South Africa. A total of 1200 feeding ixodid ticks collected from farm animals at selected homesteads were first subjected to molecular identification using mitochondrial 12S ribosomal RNA (rRNA) gene by PCR and were further tested for the presence of piroplasms through amplification of the 18S rRNA gene via nested-PCR followed by sequencing of the PCR products. The results indicated that 853 (71.1%) corresponded to the genus Rhipicephalus, 335 (27.9%) corresponded to genus Amblyomma, and 12 (1%) corresponded to genus Haemaphysalis. Amblyomma hebraeum and Rhipicephalus appendiculatus were the most common identified ticks from this study. The 18S rRNA nested-PCR revealed that 44 (3.7%) samples were confirmed positive for Theileria. A homology search for the generated sequences revealed a high percentage identity of 98–98.9% similarity to T. buffeli, T. orientalis, and T. sergenti in the GenBank. Based on the results obtained herein, we conclude that there is a big diversity of Theileria species; therefore, we suggest that this research should cover more geographical areas in order to reveal the true prevalence of this pathogen in the studied area because this will be a great step in the possible prevention of an outbreak that could have devastating effects on livestock production and human health in both the studied areas and South Africa at large.

Dynamics of Borrelia burgdorferi-Specific Antibodies: Seroconversion and Seroreversion between Two Population-Based, Cross-Sectional Surveys among Adults in Germany.

Lyme borreliosis (LB) caused by Borrelia burgdorferi spp. is the most common human tick-borne disease in Europe. Although seroprevalence studies are conducted in several countries, rates of seroconversion and seroreversion are lacking, and they are essential to determine the risk of infection. Seropositivity was determined using a two-step approach—first, a serological screening assay, and in the event of a positive or equivocal result, a confirmatory immunoblot assay. Seroconversion and seroreversion rates were assessed from blood samples taken from participants included in two nation-wide population-based surveys. Moreover, the impact of antigen reactivity on seroreversion rates was assessed. The seroprevalence of antibodies reacting against B. burgdorferi spp. in the German population was 8.5% (95% CI 7.5–9.6) in 1997–99 and 9.3% (95% CI 8.3–10.4) in 2008–2011. Seroprevalence increased with age, up to 20% among 70–79 year-olds. The age-standardized seroprevalence remained the same. The yearly seroconversion rate was 0.45% (95% CI: 0.37–0.54), and the yearly seroreversion rate was 1.47% (95% CI: 1.24–2.17). Lower levels of antibodies were associated with seroreversion. Participants with a strong response against antigen p83 had the lowest odds on seroreversion. Given the yearly seroreversion rate of 1.47% and a seroprevalence up to 20% in the oldest age groups, at least 20% of the German population becomes infected with B. burgdorferi in their lifetime. The slight increase in seroprevalence between the two serosurveys was caused by an aging population.

Humans infested with Ixodes ricinus are exposed to a diverse array of tick-borne pathogens in Serbia

Tick-borne pathogens (TBPs) pose a major threat to human health in Europe and the whole northern hemisphere. Despite a high prevalence of TBPs in Ixodes ricinus ticks, knowledge on the incidence of tick-borne diseases in humans infested by this tick species is limited. This study was conducted in the year 2019 on patients who presented themselves to the Pasteur Institute Novi Sad with tick infestations. Ticks (n = 31) feeding on human (n = 30) and blood samples from the same individuals were collected by physicians and a microfluidic real-time high-throughput PCR system was used to test the genomic DNA of the samples for the presence of 27 bacterial and eight parasitic microorganisms in Serbia. Except for one Rhipicephalus sanguineus s.l. adult male tick, all ticks infesting humans were morphologically identified as I. ricinus. A high proportion of ticks (74 %, 23/31) were infected with at least one of the tested TB microorganisms, being Rickettsia helvetica (54 %, 17/31) the most common pathogen, but Borrelia afzelii (9 %, 3/31), Anaplasma phagocytophilum (6 %, 2/31), Borrelia miyamotoi (6 %, 2/31), and Francisella like-endosymbiont (6 %, 2/31), Borrelia valaisiana (3 %, 1/31), Borrelia lusitaniae (3 %, 1/31), Rickettsia felis (3 %, 1/31) and Rickettsia aeschlimannii (3 %, 1/31) were also identified. Despite the high infection rate of TBPs in ticks, only two human blood samples (6 %, 2/30) tested positive for the presence of TBPs, one patient (code H12, 67 years old female) was diagnosed with Borrelia spp. and the other patient was diagnosed (code H17, 71 years old female) with R. felis infection. The tick infesting patient H12 tested positive for B. afzelii, and R. helvetica and the tick infesting patient H17 tested positive for R. felis. Upon clinical examination, both patients were diagnosed with erythema migrans. No additional discomfort was reported by the patient and no additional pathology was observed by the physician. We concluded that humans bitten by I. ricinus in Serbia are exposed to a diverse array of TBPs with clinical impact in the Serbian cohort studied.

Three molecules found in rosemary or nutmeg essential oils repel ticks (Dermacentor variabilis) more effectively than DEET in a no-human assay.

Development of new personal repellents to prevent tick bites is progressing to keep up with the increasing threat of tick-borne diseases in humans. However, the market share of natural, plant-based repellents is still quite small. We tested all of the major (>1%) components found in the essential oils of rosemary (Spanish variety) and nutmeg. These were tested with Dermacentor variabilis ticks, a robust tick capable of vectoring human diseases, in a no-human horizontal Petri dish assay. For comparison, we also tested the active ingredients currently recommended by the CDC and EPA as personal repellents for use against ticks. Of the 16 oil components tested, three performed significantly better than N,N-diethyl-meta-toluamide (DEET) in our assay. These compounds were myristicin and safrole found in the nutmeg oil, and terpinolene found in nutmeg oil and as a minor (<1%) constituent of rosemary oil. The current market natural product, 2-undecanone, also performed strongly in our assay. Our assay focused on comparing active ingredients as potential repellents and found that many natural products can elicit a strong response from ticks. Terpinolene is the most promising active ingredient identified, owing to human health concerns regarding myristicin and safrole. Our results from examining individual terpenoids from two essential oils suggest that there remain unexploited natural compounds that could be further developed for new personal tick repellents. © 2020 Society of Chemical Industry.

Serologic Evidence for the Exposure of Eastern Coyotes ( Canis latrans ) in Pennsylvania to the Tick-Borne Pathogens Borreliella burgdorferi and Anaplasma phagocytophilum

Lyme disease and anaplasmosis are tick-borne bacterial diseases caused by Borreliella and Anaplasma species, respectively. A comprehensive analysis of the exposure of eastern coyotes (Canis latrans) in the northeastern United States to tick-borne pathogens has not been conducted. In this report, we assess the serological status of 128 eastern coyotes harvested in Pennsylvania in 2015 and 2017 for antibodies to Borreliella burgdorferi and Anaplasma phagocytophilum Immunoblot and dot blot approaches were employed to test each plasma sample by using cell lysates and recombinant proteins as detection antigens. The results demonstrate high seropositivity incidences of 64.8% and 72.7% for B. burgdorferi and A. phagocytophilum, respectively. Antibodies to both pathogens were detected in 51.5% of the plasma samples, indicating high potential for coinfection. Antibodies to the B. burgdorferi proteins DbpB, VlsE, DbpA, BBA36, and OspF (BBO39) were detected in 67.2, 63.3, 56.2, 51.6, and 48.4% of the plasma samples, respectively. Antibodies to the A. phagocytophilum P44 and P130 proteins were detected in 72.7 and 60.9% of the plasma samples, respectively.IMPORTANCE The incidence of Lyme disease (Borreliella burgdorferi) and anaplasmosis (Anaplasma phagocytophilum) are increasing in North America and Europe. The causative agents of these debilitating tick-transmitted infections are maintained in nature in an enzootic cycle involving Ixodes ticks and diverse mammals and birds. It has been postulated that predators directly or indirectly influence the dynamics of the enzootic cycle and disease incidence. Here, we demonstrate high seropositivity of eastern coyotes for B. burgdorferi and A. phagocytophilum As coyotes become established in urban and suburban environments, interactions with humans, companion animals, and urban/suburban wildlife will increase. Knowledge of the pathogens that these highly adaptable predators are exposed to or carry, and their potential to influence or participate in enzootic cycles, is central to efforts to reduce the risk of tick-borne diseases in humans and companion animals.

Identification of Zoonotic Tick-Borne Pathogens from Korean Water Deer (Hydropotes inermis argyropus).

Korean water deer (Hydropotes inermis argyropus) are widespread in the Republic of Korea (ROK). Mostly, Korean water deer are essential hosts for maintaining ticks and tick-borne diseases (TBDs). Here, we investigated the prevalence of tick-borne pathogens (TBPs) among rescued Korean water deer. Anaplasma phagocytophilum (21.4%, 6/28), Anaplasma capra (14.3%, 4/28), Babesia capreoli (3.6%, 1/28), and Coxiella burnetii (3.6%, 1/28) were detected, but Borrelia burgdorferi, Ehrlichia, Rickettsia, and Theileria infections were not found. A. phagocytophilum was the most commonly detected pathogen, and co-infection with A. capra and B. capreoli was also noted in one Korean water deer. To our knowledge, this is the first article of B. capreoli infection in Korean water deer in the ROK. The infecting isolate of A. phagocytophilum was genetically characterized by 16S ribosomal RNA (rRNA) gene and ankyrin-related protein (ankA) gene. Although the 16S rRNA gene alone may not be informative enough to delineate distinct host species, ankA-based phylogeny revealed a high identity of Korean water deer sequences with those of the causative agent of human granulocytic anaplasmosis. A. capra was detected by using citrate synthase gene (gltA), heat-shock protein (groEL), and major surface protein 4 (msp4) genes. Phylogenetic tree based on these gene markers revealed that there were at least two distinct variants within A. capra circulating in the ROK. One variant originated from different hosts including humans, ticks, goats, and sheep, whereas the other variant was reported recently in Korean water deer in the ROK. Consequently, these sequences were identified to belong to a zoonotic species. Sequencing analysis of the 18S rRNA gene revealed that our isolate belonged to B. capreoli and was distinct from Babesia divergens and Babesia venatorum. Moreover, our isolate showed 92.2% homology with B. capreoli sequences, indicating that these differences may be attributed to the different tick species that transmit B. capreoli or to different host species. Genotyping and phylogenetic analysis of C. burnetii based on 16S rRNA and IS1111 genes revealed that our isolate was grouped with several strains of C. burnetii and was genetically distant from Coxiella-like bacteria isolates. The present results highlight that Korean water deer act as potential reservoir hosts for zoonotic TBPs, and thus play an important role in the transmission of TBDs in humans, animals, and livestock.

Predominant risk factors for tick-borne co-infections in hunting dogs from the USA

BackgroundBoth incidence and geographical range of tick-borne disease has increased across the USA. Similar to people, dogs are hosts for Anaplasma spp., Babesia spp., Ehrlichia spp. and Borrelia burgdorferi. Dogs also share our homes and beds, making them both a sentinel for the ticks in our backyards but also increasing our exposure to ticks. Measures to better track, prevent, and/or treat tick-borne diseases in companion animals can lead to better control and prevention of human tick-borne disease. This study identifies demographic and co-infection risk factors for canine seropositivity to tick-borne infections in a cohort of hunting dogs across the USA.ResultsHuman patterns of tick-borne disease co-infection in the USA have been predominantly driven by the geographical distribution of the tick vector. Dogs who tested seropositive for Anaplasma spp. were 1.40 times more likely (P = 0.0242) to also test seropositive for Babesia spp. and vice versa (1.60 times more likely, P = 0.0014). Dogs living in the West had 5% lower risk (P = 0.0001) for Ehrlichia spp. seropositivity compared to other regions. Controlling for age and Anaplasma spp. seroprevalence, dogs in all three other regions were 2.30 times more likely (P = 0.0216) to test seropositive for B. burgdorferi than dogs in the West. Dogs seropositive for B. burgdorferi were 1.60 times more likely (P = 0.0473) to be seropositive for Anaplasma spp.ConclusionsTick geographical distributions have a prominent impact on the regional distribution of hunting dog exposure to tick-borne diseases. Education concerning regional tick prevalence and disease risk is important for everyone, but particularly dog owners, regarding ticks in their region and protection from infection and co-infection of tick-borne pathogens as they travel or move with their dogs. Dogs are sentinel species for human exposure to ticks, and as such surveillance of canine tick-borne infections and understanding the probability that these infections might be seen together as co-infections helps predict emerging areas where people are more likely to be exposed as well.

Barriers to Effective Tick Management and Tick-Bite Prevention in the United States (Acari: Ixodidae).

Lyme and other tick-borne diseases are increasing in the United States. Development of tick control tools have focused primarily on the blacklegged tick, Ixodes scapularis Say. Application of acaricides or entomopathogenic fungal agents to kill host-seeking ticks or ticks on rodents can suppress I. scapularis abundance in residential landscapes, but evidence is lacking for impact on human tick bites or tick-borne disease. Similar studies remain limited for the lone star tick, Amblyomma americanum (L.). Other knowledge gaps include how well homeowners and pest control companies perform in the broadcast application of tick-killing products, relative to high efficacy reported in research studies, and the tick-killing potential of natural product formulations exempt from Environmental Protection Agency registration. Area-wide control based on preventing ticks from feeding on their main reproductive host, the white-tailed deer, can suppress populations of both I. scapularis and A. americanum. Some studies also suggest an impact on Lyme disease cases, but this needs to be further validated in larger-scale intervention studies. The effectiveness, scale, cost, and implementation of various tick management strategies are important considerations in efforts to reduce human tick encounters and tick-borne disease. Additional barriers include weak incentives for industry and academia to develop, test, and register new tick and pathogen control technologies, including vaccines targeting humans, tick reproductive hosts, or wildlife pathogen reservoirs. Solutions will need to be 'two-pronged': improving the tick and pathogen control toolbox and strengthening the public health workforce engaging in tick control at local and state levels.

Local Population Structure and Seasonal Variability of Borrelia garinii Genotypes in Ixodes ricinus Ticks, Slovakia.

Lyme disease (LD) is the most common tick-borne human disease in Europe, and Borrelia garinii, which is associated with avian reservoirs, is one of the most genetically diverse and widespread human pathogenic genospecies from the B. burgdorferi sensu lato (s.l.) complex. The clinical manifestations of LD are known to vary between regions and depend on the genetic strain even within Borrelia genospecies. It is thus of importance to explore the genetic diversity of such pathogenic borreliae for the wide range of host and ecological contexts. In this study, multilocus sequence typing (MLST) was employed to investigate the local population structure of B. garinii in Ixodes ricinus ticks. The study took place in a natural wetland in Slovakia, temporally encompassing spring and autumn bird migration periods as well as the breeding period of resident birds. In total, we examined 369 and 255 ticks collected from 78 birds and local vegetation, respectively. B. burgdorferi s.l. was detected in 43.4% (160/369) of ticks recovered from birds and in 26.3% (67/255) of questing ticks, respectively. Considering the ticks from bird hosts, the highest prevalence was found for single infections with B. garinii (22.5%). Infection intensity of B. garinii in bird-feeding ticks was significantly higher than that in questing ticks. We identified ten B. garinii sequence types (STs) occurring exclusively in bird-feeding ticks, two STs occurring exclusively in questing ticks, and one ST (ST 244) occurring in both ticks from birds and questing ticks. Four B. garinii STs were detected for the first time herein. With the exception of ST 93, we detected different STs in spring and summer for bird-feeding ticks. Our results are consistent with previous studies of the low geographic structuring of B. garinii genotypes. However, our study reveals some consistency in local ST occurrence and a geographic signal for one of the clonal complexes.

Time-resolved proteomic profile of Amblyomma americanum tick saliva during feeding.

Amblyomma americanum ticks transmit more than a third of human tick-borne disease (TBD) agents in the United States. Tick saliva proteins are critical to success of ticks as vectors of TBD agents, and thus might serve as targets in tick antigen-based vaccines to prevent TBD infections. We describe a systems biology approach to identify, by LC-MS/MS, saliva proteins (tick = 1182, rabbit = 335) that A. americanum ticks likely inject into the host every 24 h during the first 8 days of feeding, and towards the end of feeding. Searching against entries in GenBank grouped tick and rabbit proteins into 27 and 25 functional categories. Aside from housekeeping-like proteins, majority of tick saliva proteins belong to the tick-specific (no homology to non-tick organisms: 32%), protease inhibitors (13%), proteases (8%), glycine-rich proteins (6%) and lipocalins (4%) categories. Global secretion dynamics analysis suggests that majority (74%) of proteins in this study are associated with regulating initial tick feeding functions and transmission of pathogens as they are secreted within 24–48 h of tick attachment. Comparative analysis of the A. americanum tick saliva proteome to five other tick saliva proteomes identified 284 conserved tick saliva proteins: we speculate that these regulate critical tick feeding functions and might serve as tick vaccine antigens. We discuss our findings in the context of understanding A. americanum tick feeding physiology as a means through which we can find effective targets for a vaccine against tick feeding.

Tick-borne infections of dogs in Serbia: A review of research

Increased prevalence of tick-borne disease in humans and animals is an important public health issue. Dogs can be clinically ill, reservoirs of tick-borne pathogens, or sentinel populations for research. Certainly, small-scale research has been conducted in dogs and this review will focus on the recent studies of emergent and re-emergent tick-borne pathogens in dogs in Serbia. Babesiosis stands out as the most common and important tick-borne disease in dogs. In addition to this pathogen, the presence of Hepatozoon canis and ?Candidatus Mycoplasma haematoparvum? in the blood of dogs was proved using molecular methods. Seroreactivity in dogs has been proven for Borrelia burgdorferi sensu lato (s.l.) complex, Ehrlichia canis, Ehrlichia ewingii, Anaplasma phagocytophilum, Anaplasma platys, Rickettsia conorii, and tick-borne encephalitis virus (TBEV). The presence of B. burgdorferi s.l. complex, A. phagocytophilum, Rickettsia spp. from the group of spotted fevers, and TBEV in ticks indicates the geographical distribution and potential for infecting humans, dogs, and other animals in Serbia. Further systematic, comprehensive, well designed, bacteriological, virological, parasitological, epidemiological, clinical (infectological), and acarological research is needed in Serbia.

2310. No Recurrence in Recovered People with CCHF: A Cross-Sectional Study From Turkey, Preliminary Report

BackgroundCrimean-Congo hemorrhagic fever (CCHF) is a widespread, tick-borne disease of humans. CCHF is an endemic in Turkey, and since 2004 many cases have been reported from different regions in the country. CCHF infection in humans can lead to antibody responses that can be protective but there is limited data about the immunity of CCHF. The aim of this study was to investigate the possibility of recurrence of CCHF in people who previously had this disease.MethodsThe patients who were diagnosed with CCHF between 2005 and 2018 were followed up and contacted via phone in order to answer several survey questions about CCHF. Patients who still live in the same places, who have high risks of disease transmission because of husbandry or farming and high potential of contact with ticks were included in this study. Those who changed their living place and stopped husbandry or farming were excluded from this study. The questions in the survey are the following: Have you had CCHF after your discharge from the hospital?; Has there been any tick contact?; Did you ever get a tick removed from your body? Did you or your family members have CCHF at the same time or at different periods of time? Has anyone had CCHF in the area you live? Do your animals have ticks? Do you live in the same place? Have you changed your job?ResultsNinety-nine out of 351 patients who were contacted via phone had data eligible to be included in the criteria. The amount of time elapsed after the discharge of the patients was between 1 and 14 years in average. None of the patients had experienced CCHF disease again. Also, 6 of these patients were bitten by ticks repeatedly (2–5 times). An average of 7–10 years had passed since the transmission of the disease by the patients.ConclusionThe results show that the CCHF disease creates an immune response and this response continues for a long time. The findings will be more enlightening with the measurement of the serum antibody levels of patients.Disclosures All authors: No reported disclosures.

Knowledge, Attitudes, and Practices on Tick-Borne Human Diseases and Tick-Borne Encephalitis Vaccine among Farmers from North-Eastern Italy (2017)

ABSTRACTObjectives: Tick-borne diseases (T-BD) represent a potential health threat for outdoor workers in endemic areas, such as the Autonomous Province of Trento (APT). We conducted a questionnaire-based survey to assess T-BD knowledge, attitudes, and preventive practices among APT farmers, specifically focusing on the use of protective habits and the uptake of the tick-borne encephalitis (TBE) vaccine.Methods: A convenience sample of 106 farmers (all males, mean age 47.3 ± 13.6 years) attending pesticide training courses (12/2016–03/2017) completed the anonymous survey. Binary regression analysis, calculations of multivariate odds ratios (mOR) and 95% confidence intervals were used to assess knowledge, attitudes, and risk perceptions as predictors of preventive measures.Results: Though general understanding of T-BD was fairly low, the majority of the participants perceived TBE infection as a frequent (73.6%) and severe disease (61.3%). Overall, 43.3% of participants knew a TBE vaccine was available, and 24.5% had been vaccinated. Protective habits were reported by 53.8% of respondents, with self-checks for tick bites particularly low at 2.8% of participants. Better knowledge of T-BD and favorable attitudes toward vaccinations were associated with TBE immunization (mOR 4.708; 95%CI 1.273–17.409 and mOR 3.555; 95%CI 1.175–10.760, respectively), while previous history of tick bite and any interaction with T-BD significantly predicted adherence to protective measures (mOR 4.458; 95%CI 1.808–10.991, and mOR 9.433; 95%CI 1.127–78.973, respectively).Conclusions: Adherence to preventive measures (TBE vaccine) and protective habits was unsatisfactory in our sampled group, being a possible consequence of significant knowledge gaps. Public health communication on T-BD in farmers should, therefore, target understanding of health issues and appropriate preventive measures.

A Vaccinomics Approach for the Identification of Tick Protective Antigens for the Control of Ixodes ricinus and Dermacentor reticulatus Infestations in Companion Animals.

Ticks and tick-borne pathogens affect health and welfare of companion animals worldwide, and some human tick-borne diseases are associated with exposure to domestic animals. Vaccines are the most environmentally friendly alternative to acaracides for the control of tick infestations, and to reduce the risk for tick-borne diseases affecting human and animal health. However, vaccines have not been developed or successfully implemented for most vector-borne diseases. The main limitation for the development of effective vaccines is the identification of protective antigens. To address this limitation, in this study we used an experimental approach combining vaccinomics based on transcriptomics and proteomics data with vaccination trials for the identification of tick protective antigens. The study was focused on Ixodes ricinus and Dermacentor reticulatus that infest humans, companion animals and other domestic and wild animals, and transmit disease-causing pathogens. Tick larvae and adult salivary glands were selected for analysis to target tick organs and developmental stages playing a key role during tick life cycle and pathogen infection and transmission. Two I. ricinus (heme lipoprotein and uncharacterized secreted protein) and five D. reticulatus (glypican-like protein, secreted protein involved in homophilic cell adhesion, sulfate/anion exchanger, signal peptidase complex subunit 3, and uncharacterized secreted protein) proteins were identified as the most effective protective antigens based on the criteria of vaccine E > 80%. The putative function of selected protective antigens, which are involved in different biological processes, resulted in vaccines affecting multiple tick developmental stages. These results suggested that the combination of some of these antigens might be considered to increase vaccine efficacy through antigen synergy for the control of tick infestations and potentially affecting pathogen infection and transmission. These antigens were proposed for commercial vaccine development for the control of tick infestations in companion animals, and potentially in other hosts for these tick species.

The effect of sublethal concentrations of deltamethrin and alphacypermethrin on the fecundity and development of Ixodes ricinus (Acari: Ixodidae) eggs and larvae

Two pyrethroids, deltamethrin (D) and alphacypermethrin (AC), have been used as commercial products for tick control worldwide. However, the effects of sublethal doses of these compounds on various tick species and their developmental stages have not been fully explored yet, although such knowledge could contribute to a more effective application of both pyrethroids and simultaneous reduction of their costs and undesirable side effects, including the harmful impact on other organisms and environmental contamination. This study investigates the effect of sublethal concentrations of D and AC applied to engorged females on the fecundity, development of eggs and larvae, and the number of offspring in the Ixodes ricinus (L.) tick, which is the most important vector of tick-borne diseases of humans in Europe. After detachment from rabbit’s skin, fully engorged I. ricinus females were treated with 20 μl of pyrethroid solutions at five concentrations from 0.01562 to 0.25% and kept at 28 °C and 75% relative humidity. The impact of the pyrethroids on maturation and development of eggs as well as development of larvae was assessed based on parameters of the preoviposition and oviposition periods and the course of embryogenesis and egg hatch. The investigations have shown that both tested acaricides reduce the reproductive rate in I. ricinus females by inhibition of egg development and disturb embryonic development and larval hatch. Females did not lay eggs at concentrations higher than 0.0625% AC and 0.125% D. The lower concentrations of both pyrethroids disturbed or inhibited the embryogenesis and egg hatch in I. ricinus.

Tick species establishment in Oklahoma County, Oklahoma, U.S.A., identified by seasonal sampling in residential and non-residential sites.

In recent years, human tick-borne disease occurrence has risen in Oklahoma, U.S.A., but year-round data on tick presence in frequently used recreational areas is not widely available. In this study, ticks were collected monthly for one year at residential and non-residential sites in a suburban area of Oklahoma County, OK, U.S.A. At each trapping site, dry ice traps were used in both woodland and grassland areas and fabric tick drags were used in grassland areas. Four species were collected from each park: Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, and Ixodes scapularis. Prior to this study, A. americanum was the only species with an established population in Oklahoma County. Consistent with this, A. americanum was collected in all months of the year and accounted for over 90% of ticks collected at each site. Based on our tick survey, we report that A. maculatum, D. variabilis, and I. scapularis, which were each collected in numbers greater than six within a single sampling occasion, are now each confirmed as established populations in Oklahoma County.

Mitochondrial Gene Heterogeneity and Population Genetics of Haemaphysalis longicornis (Acari: Ixodidae) in China.

Haemaphysalis longicornis is an important ectoparasite of domestic and wild animals that can transmit many pathogens including viruses, fungi, bacteria and protozoa. In this study, we examined genetic variation and population genetics in three mitochondrial (mt) genes [cox1 (cytochrome c subunit 1), rrnL (large subunit ribosomal RNA) and nad5 (NADH dehydrogenase 5)] among four H. longicornis populations from China. The sizes of the partial sequences of cox1, rrnL and nad5 were 776bp, 409bp, 510bp, respectively. Among the obtained sequences, we identified 22 haplotypes for cox1, 2 haplotypes for rrnL and 17 haplotypes for nad5. Low gene flow and significant genetic differentiation (66.2%) were detected among H. longicornis populations. There was no rapid expansion event in the demographic history of four H. longicornis populations in China. In addition, phylogenetic analyses confirmed that all the Haemaphysalis isolates were H. longicornis which were segregated into two major clades. The mt DNA genes provide a potential novel genetic marker for molecular epidemiology of H. longicornis and assist in the control of tick and tick-borne diseases in humans and animals.

Host feeding behaviour of Dermacentor reticulatus males in relation to the transmission of pathogens.

The three-host Dermacentor reticulatus tick transmits many pathogens, which are introduced into the host with saliva during feeding. The aim of present study was to analyse the behaviour of males of this species on the host in homogeneous sex groups comprising 15 (group I) and 30 (group II) male specimens and in a mixed group composed of 15 males and 15 females (group III). Although the dynamics of attachment of the males to host skin slightly differed between these three groups, there was no statistically significant difference in the duration of the attachment process. The duration of host attachment of the males in groups I, II, and III at 18±2°C and 50 ± 2% RH was 2.43 ± 2.46, 7.75 ± 11.85, and 9.07 ± 10.97 days, respectively. After 7-9-day feeding, the male engorgement weight (MEW) was similar, regardless of the size of the group and the presence or absence of females on the host. Tick males ingest a small amount of host blood. The value of MEW in the three groups did not differ statistically from the weight of unengorged specimens. The host feeding behaviour of D. reticulatus males and their effective feeding suggest that they may play a role in transmission of pathogens and non-pathogenic microorganisms with tick saliva during blood meal ingestion. Clinical and laboratory diagnostics of human and animal tick-borne diseases as well as epidemiological studies should consider the possibility of pathogen transmission by males of metastriata ticks, which feed on the host for several days.

Diversity of Anaplasma and Ehrlichia/Neoehrlichia Agents in Terrestrial Wild Carnivores Worldwide: Implications for Human and Domestic Animal Health and Wildlife Conservation.

Recently, the incidence and awareness of tick-borne diseases in humans and animals have increased due to several factors, which in association favor the chances of contact among wild animals and their ectoparasites, domestic animals and humans. Wild and domestic carnivores are considered the primary source of tick-borne zoonotic agents to humans. Among emergent tick-borne pathogens, agents belonging to family Anaplasmataceae (Order Rickettsiales) agents stand out due their worldwide distribution and zoonotic potential. In this review we aimed to review the genetic diversity of the tick-transmitted genera Ehrlichia, Anaplasma and “Candidatus Neoehrlichia sp.” in wild carnivores Caniformia (Canidae, Mustelidae and Ursidae) and Feliformia (Felidae, Hyanidae, Procyonidae and Viverridae) worldwide, discussing the implications for human and domestic animal health and wildlife conservation. Red foxes (Vulpes vulpes) have been identified as hosts for Anaplasma spp. (A. phagocytophilum, Anaplasma ovis, A. platys), Ehrlichia canis and “Candidatus Neoehrlichia sp.” (FU98 strain) and may contribute to the maintaenance of A. phagocytophilum in Europe. Raccoons (Procyon lotor) have been reported as hosts for E. canis, A. bovis, “Candidatus Neoehrlichia lotoris” and A. phagocytophilum, and play a role in the maintenance of A. phagocytophilum in the USA. Raccoon dogs (Nyctereutes procyonoides) may play a role as hosts for A. bovis and A. phagocytophilum. New Ehrlichia and/or Anaplasma genotypes circulate in wild canids and felids from South America and Africa. While Ehrlichia sp. closely related to E. canis has been reported in wild felids from Brazil and Japan, Anaplasma sp. closely related to A. phagocytophilum has been detected in wild felids from Brazil and Africa. Red foxes and mustelids (otters) are exposed to E. canis in countries located in the Mediaterranean basin, probably as a consequence of spillover from domestic dogs. Similarly, E. canis occurs in procyonids in North (raccoons in USA, Spain) and South (Nasua nasua in Brazil) Hemispheres, in areas where E. canis is frequent in dogs. While “Candidatus Neoehrlichia lotoris” seems to be a common and specific agent of raccoons in the USA, “Candidatus Neoehrlichia sp.” (FU98 strain) seems to show a broader range of hosts, since it has been detected in red fox, golden jackal (Canis aureus) and badger (Meles meles) in Europe so far. Brown (Ursus arctos) and black (Ursus americanus) bears seem to play a role as hosts for A. phagocytophilum in the North Hemisphere. Anaplasma bovis has been detected in wild Procyonidae, Canidae and Felidae in Asia and Brazil. In order to assess the real identity of the involved agents, future works should benefit from the application of MLST (Multi Locus Sequence Typing), WGS (Whole Genome Sequencing) and NGS (Next Generation Sequencing) technologies aiming at shedding some light on the role of wild carnivores in the epidemiology of Anaplasmataceae agents.