Three-host Tick Research Articles

Comparative Analysis of Bisexual and Parthenogenetic Populations in Haemaphysalis Longicornis.

Haemaphysalis longicornis, a three-host tick with a wide host range, is widely distributed in different countries and regions. It stands out among ticks due to its unique feature of having both parthenogenetic and bisexual populations. Despite their morphological resemblance, the characteristics of the parthenogenetic population have been overlooked. In this comprehensive study, we systematically compared the similarities and differences between these two populations. Our investigation revealed that the parthenogenetic H. longicornis, widely distributed in China, was found in ten provinces, surpassing the previously reported distribution. Notably, individuals from the parthenogenetic population exhibited a prolonged blood-feeding duration during the larval and nymph stages compared to their bisexual counterparts. Additionally, the life cycle of the parthenogenetic population was observed to be longer. A flow cytometry analysis indicated a DNA content ratio of approximately 2:3 between the bisexual and parthenogenetic populations. A phylogenetic analysis using whole mitochondrial genome sequences resulted in the separation of the phylogenetic tree into two distinct branches. A molecular analysis unveiled a consistent single T-base deletion at nucleotide 8497 in the parthenogenetic population compared to the bisexual population. Both populations displayed high viral infection capability and significant resistance to ivermectin. Intriguingly, despite these differences, the parthenogenetic population exhibited a similar life cycle to the bisexual population, retaining the ability to transmit pathogens such as Severe fever with thrombocytopenia syndrome virus (SFTSV) and Heartland Virus (HRTV). These findings contribute to a deeper understanding of the distinct characteristics and similarities between different populations of H. longicornis, laying the foundation for future research in this field.

New insights into the systematics of the afrotropical Amblyomma marmoreum complex (Acari: Ixodidae) and the genome of a novel Rickettsia africae strain using morphological and metagenomic approaches

The Amblyomma marmoreum complex includes afrotropical species, such as Amblyomma sparsum, a three-host tick that parasitizes reptiles, birds, and mammals, and is a recognized vector of Ehrlichia ruminantium. However, the lack of morphological, genetic and ecological data on A. sparsum has caused considerable confusion in its identification. In this study, we used microscopy and metagenomic approaches to analyze A. sparsum ticks collected from a puff adder snake (Bitis arietans) in southwest Senegal (an endemic rickettsioses area) in order to supplement previous morphological descriptions, provide novel genomic data for the A. marmoreum complex, and describe the genome of a novel spotted fever group Rickettsia strain. Based on stereoscope and scanning electron microscopy (SEM) morphological evaluations, we provide high-quality images and new insights about punctation and enameling in the adult male of A. sparsum to facilitate identification for future studies. The metagenomic approach allowed us assembly the complete mitochondrial genome of A. sparsum, as well as the nearly entire chromosome and complete plasmid sequences of a novel Rickettsia africae strain. Phylogenomic analyses demonstrated a close relationship between A. sparsum and Amblyomma nuttalli for the first time and confirmed the position of A. sparsum within the A. marmoreum complex. Our results provide new insights into the systematics of A. sparsum and A. marmoreum complex, as well as the genetic diversity of R. africae in the Afrotropical region. Future studies should consider the possibility that A. sparsum may be a vector for R. africae.

In vitro feeding of all life stages of two-host Hyalomma excavatum and Hyalomma scupense and three-host Hyalomma dromedarii ticks

Ticks are blood-sucking ectoparasites and can transmit various pathogens of medical and veterinary relevance. The life cycle of ticks can be completed under laboratory conditions on experimental animals, but the artificial feeding of ticks has attracted increased interest as an alternative method. This study represents the first report on the successful in vitro feeding of all life stages of two-host tick species, Hyalomma scupense and Hyalomma excavatum, and the three-host tick Hyalomma dromedarii. The attachment and engorgement rates of adults were 84% (21/25) and 76% (19/25) for H. scupense females. For adult H. excavatum and H. dromedarii, 70% (21/30) and 34.4% (11/32) of the females attached and all attached females successfully fed to repletion. The oviposition rates of the artificially fed females were 36.4%, 57.1% and 63.1% for H. dromedarii, H. excavatum and H. scupense, respectively, with a reproductive efficiency index varying between 44.3 and 60.7%. For the larvae, the attachment and engorgement rates were 44.2% (313/708) and 42.8% (303/708) for H. dromedarii, 70.5% (129/183) and 56.8% (104/183) for H. excavatum and 92.6% (113/122) and 55.7% (68/122) for H. scupense. The attachment and engorgement rates for the nymphs were 90.2% (129/143) and 47.6% (68/143) for H. dromedarii, 66.7% (34/51) and 41.2% (21/51) for H. excavatum, and 44.1% (30/68) and 36.8% (25/68) for H. scupense. Molting rates of the immature stages varied between 71.3% (216/303) and 100% (68/68) for the larvae and between 61.9% (13/21) and 96% (24/25) for the nymphs. The successful in vitro feeding of all stages of the three Hyalomma species makes this method a valuable tool for tick research, with potential applications in studies on the pathogens transmitted by these tick species such as Theileria annulata.

Key molecules regulating the blood meals of Rhipicephalus sanguineus (Acari: Ixodidae) revealed by transcriptomics.

Rhipicephalus sanguineus, a repulsive obligate blood feeder, is a three-host tick inflicting tremendous damage. Blood-sucking initiates tick-pathogen-host interactions along with alterations in the expression levels of numerous bioactive ingredients. Key molecules regulating blood meals were identified using the transcriptomic approach. A total number of 744 transcripts showed statistically significantly differential expression including 309 significantly upregulated transcripts and 435 significantly downregulated transcripts in semiengorged female ticks compared to unfed ticks, all collected in 2021. The top 10 differentially upregulated transcripts with explicit functional annotations included turripeptide OL55-like protein, valine tRNA ligase-like protein and ice-structuring glycoprotein-like protein. The top 10 differentially down-regulated transcripts were uncharacterized proteins. Gene Ontology (GO) enrichment analysis revealed four associated terms in the cellular component category and 16 in the molecular function category among the top 20 terms. Differentially expressed genes (DEGs) were enriched in GO terms ID 0000323 (lytic vacuole) and ID 0005773 (vacuole). The top 20 enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways included metabolism, cellular processes, organismal systems and human diseases. The DEGs were enriched in the KEGG term ID: ko-04142 (lysosome pathway) associated with intracellular digestion in the tick midgut epithelium. Molecular markers annotated via comparative transcriptomic profiling were expected to be candidate markers for the purpose of tick control.

Determination of a Discriminant Dose to Identify Resistance to Amitraz in Rhipicephalus sanguineus s.l. (Acari: Ixodidae) from Mexico.

The brown dog tick, Rhipicephalus sanguineus s.l., is considered the most widely distributed three-host tick in the world and has medical and veterinary importance; the control of infestation is carried out with acaricides, towards which it can develop resistance. This study aimed to determine the discriminant dose (d.d) of amitraz to identify resistance in R. sanguineus s.l. larvae natives from Mexico and to evaluate its application in field-collected ticks. Engorged ticks were collected from naturally infested dogs residing in rural communities and were incubated for 25 days, and their progeny was used in a larval immersion test (LIT) to be exposed to the d.d. determined in Rhipicephalus microplus, and those that were susceptible were analyzed using the LIT in six concentrations. Mortality was analyzed through probit methodology to calculate the lethal concentration (LC) 50 and 99. The d.d. was determined as a consensus value by multiplying the LC99 × 2, and then, we proceeded to evaluate it in in-field samples by using the LIT technique. The d.d. calculated was 4 ppm. The in-field evaluation found 64% of the resistant samples to amitraz with mortality percentages between 98.3% and 0.35%. This dose can be used to rapidly and inexpensively identify resistant populations in samples collected in the field.

Modeling of historical and current distributions of lone star tick, Amblyomma americanum (Acari: Ixodidae), is consistent with ancestral range recovery.

The lone star tick, Amblyomma americanum L., is a three-host hard tick notorious for aggressive feeding behavior. In the early to mid-20th century, this species' range was mostly limited to the southern USA. Since the 1950s, A. americanum has been detected in many new localities in the western, northcentral, and northeastern regions of the country. To examine the influence of climate on this apparent expansion, we used historical (1748-1950) lone star locations from the literature and museum records to model areas suitable for this species based on past environmental conditions in the late 1800s - early 1900s. We then projected this model forward using present (2011-2020) climatic conditions and compared the two for evidence of climate-associated distributional shifts. A maximum entropy distribution or Maxent model was generated by using a priori selected climatic variables including temperature, precipitation, and vapor pressure deficit. Temperature and vapor pressure deficit were selected as the most important factors in creating a sensitive and specific model (success rate = 82.6 ± 6.1%) that had a good fit to the existing data and was significantly better than a random model [partial ROC (receiver operating characteristic) to AUC (area under the ROC curve) ratio = 1.97 ± 0.07, P < 0.001]. The present projected model was tested with an independent dataset of curated museum records (1952-2020) and found to be 95.6% accurate. Comparison of past and present models revealed > 98% A. americanum niche overlap. The model suggests that some areas along the western fringe are becoming less suitable for A. americanum, whereas areas in some Great Lakes and coastal northeastern regions are becoming more suitable, results that are compatible with possible effects of climate change. However, these changes are minor, and overall climate in North America does not appear to have changed in ways significant to A. americanum's distribution. These findings are consistent with an alternative hypothesis that recent changes in A. americanum's distribution are a result of this species re-occupying its historical range, driven predominantly by factors other than climate, such as shifts in land use and population densities of major hosts.

Where have all the grouse ticks gone? Apparent decline in collections of Haemaphysalis chordeilis Packard.

Haemaphysalis chordeilis Packard, also known as the grouse or bird tick, is a three-host tick native to North America. Literature from the early 20th century reported a widespread distribution of this tick across the US and Canada. As its name implies, ground-dwelling birds such as grouse and quail were frequent hosts, and occasionally large infestations were reported in domestic flocks making it a pest of economic importance. However, after the mid-1900's records of this species appear scarce, and a number of more recent studies of ticks on birds (including ostensibly favored host species) did not detect it. To confirm this perception with data, we conducted a literature search for collection records of this species and compared the records across two eras (pre-1965 and post-1965), finding very few records of H. chordeilis in recent years, despite increased attention brought to this genus by the detection of exotic Haemaphysalis longicornis Neumann populations in the eastern US. We also compiled a list of studies after 1965 that examined appropriate hosts for ectoparasites but failed to find H. chordeilis. We interpret the apparent decline of ticks in the context of documented population declines in several major host species over the same time frame and discuss whether ectoparasite populations should be subject to the same conservation consideration as their hosts.

Amblyomma americanum (Lone star tick)

Amblyomma americanum, the lone star tick, is an aggressive three-host tick common in eastern North America with intense populations in the southern USA. Lone star ticks are sustained by feeding on white-tailed deer, ground-nesting birds, and a variety of other wild animals. These ticks also readily feed on humans and domestic animals, transmitting several pathogens. In apparent response to changes in habitat and host populations, the geographic distribution of this vector has contracted and expanded over the past century, spreading northward in recent decades, reclaiming its historic range.

Haemaphysalis hoodi (Acari: Ixodidae) on a human from Yaoundé, Cameroon, and its molecular characterization

The genus Haemaphysalis Koch, 1844 (Acari: Ixodidae) is the second-largest genus, with more than 170 described species that primarily parasitize mammals and birds (Guglielmone et al. 2014, Guglielmone et al. 2020). Haemaphysalis species are three-host ticks, mainly distributed in southern and southeastern Asia and tropical Africa (Guglielmone et al. 2014). The present study identified a tick, Haemaphysalis hoodi Warburton & Nuttall, 1909, collected from a human in Yaoundé, Cameroon. This tick species feed on birds in sub-Saharan Africa. To the best of our knowledge, this is the second record of H. hoodi from humans. In addition, 16S ribosomal RNA and cytochrome oxidase I sequences were generated for this species for the first time. Screening pan-Rickettsia-PCR infection gave a negative result.

Dermal secretion physiology and thermoregulation in the lone star tick, Amblyomma americanum

Ticks are hematophagous ectoparasites that transmit a wide range of pathogens. The lone star tick, Amblyomma americanum, is one of the most widely distributed ticks in the Midwest and Eastern United States. Lone star ticks, as other three-host ixodid ticks, can survive in harsh environments for extended periods without a blood meal. Physiological mechanisms that allow them to survive during hot and dry seasons include thermal tolerance and water homeostasis. Dermal fluid secretions have been described in metastriate ticks including A. americanum. We hypothesized that tick dermal secretion in the unfed tick plays a role in thermoregulation, as described in other hematophagous arthropods during blood feeding. In this study, we found that physical contact with a heat probe at 45 °C or high environmental temperature at ∼50 °C can trigger dermal secretion in A. americanum and other metastriate ticks in the off-host period. We demonstrated that dermal secretion plays a role in evaporative cooling when ticks are exposed to high temperatures. We find that type II dermal glands, having paired two cells and forming large glandular structures, are the source of dermal secretion. The secretion was triggered by an injection of serotonin, and the serotonin-mediated secretion was suppressed by a pretreatment with ouabain, a Na/K-ATPase blocker, implying that the secretion is controlled by serotonin and the downstream Na/K-ATPase.

Population genetic structure of the elephant tick Amblyomma tholloni from different elephant populations in Kenya

Understanding factors that shape tick population genetic structure is important as they may be exploited in crafting strategies for vector control. Amblyomma tholloni, or “elephant tick” is a three-host tick whose adults preferentially parasitize African elephants. The aim of this study was to determine the influence of fragmentation of the host populations on the genetic structure of this tick species from different ecosystems in Kenya, using the second internal transcribed spacer (ITS-2) and mitochondrial cytochrome oxidase 1 (CO1) loci. Population genetic analysis of ticks collected from four elephant populations using ITS-2 and CO1 loci revealed high gene diversity. Gene diversity at the ITS-2 locus was 0.91 and the nucleotide diversity was, 0.01. ITS-2 gene diversity was highest in Laikipia-Samburu ecosystem (0.947) and lowest in Tsavo (0.80). The CO1 locus also had high gene diversity, 0.790, and low nucleotide diversity, 0.006, and like ITS-2, gene diversity was higher in Laikipia-Samburu ecosystem (1.00) and lower in Tsavo (0.286). There was a modest statistically significant genetic differentiation among the four tick populations based on ITS-2 (FST = 0.104, P < 0.001; ΦST = 0.105, P < 0.001), and a 10% of molecular variance attributed to genetic variation between populations. There was also statistically significant differentiation among tick populations using haplotype frequencies for CO1 locus (FST = 0.167, P < 0.001) accounting for 17% of genetic variance among populations, but not modelled genetic distances (ΦST = 0.029, P = 0.095) suggesting very recent genetic differentiation. In addition, populations of A. tholloni in Kenya had a significantly negative Tajima D and Fu & Li's F* and D* at the CO1 locus suggesting recent positive selection. The extensive acaricide use in livestock, which host the larval stage, could be driving purifying selection and genetic hitchhiking of the CO1 locus. However, tests sensitive to demography such as Fu's FS, Ramos-Onsins & Rozas's R2 and raggedness index r were statistically significant at the ITS-2 locus suggesting ancient demographic expansion. Elephant population fragmentation appears to shape the genetic structure of A. tholloni, while agro-ecological factors could influence the genetic diversity of ticks.

Ixodes scapularis (Ixodida: Ixodidae) Parasitizing an Unlikely Host: Big Brown Bats, Eptesicus fuscus (Chiroptera: Vespertilionidae), in New York State, USA.

Ixodes scapularis Say is a three-host tick that has been recorded feeding on over 150 different species of terrestrial vertebrates (mammals, birds, and reptiles). This tick is found throughout the northeastern, coastal southeastern, and upper midwestern United States and is considered the most significant vector of tick-borne pathogens to humans in North America. Despite its ubiquity and broad host range, I. scapularis previously has not been reported feeding on bats (Chiroptera). However, during 2019 and 2020, larvae and nymphs of I. scapularis were recovered from big brown bats, Eptesicus fuscus (Palisot de Beauvois), at four locations in rural New York State, USA. All Ixodes infested bats were injured and found on the ground; therefore, parasitism by I. scapularis was likely opportunistic. Nonetheless, the large number of pathogens known to be associated with bats and the frequency with which I. scapularis bites people suggest that this host-tick relationship is of at least potential epidemiological significance.

Integrative Taxonomy of Dermacentor variabilis (Ixodida: Ixodidae) with Description of a New Species, Dermacentor similis n. sp.

Dermacentor variabilis is the most widely distributed three-host tick in North America, and transmits a variety of pathogens. Within the United States, this species has a discontinuous distribution, widespread east of the Rocky Mountains and with a few populations west of the Rockies. Phylogenetic evidence based on individual markers or relatively small data sets has suggested that populations at both sides of this geographic barrier may correspond to two different species. In this study, we further explore this hypothesis using an integrative taxonomy framework. Both molecular (mitochondrial and nuclear markers) and morphological analyses of specimens collected from central-eastern and western states were performed to explore species delimitation in this taxon. Results from these analyses were consistent, and provide strong evidence that D. variabilis actually corresponds to two species. Herein, the western populations are described as a new species, Dermacentor similis n. sp. The usefulness of integrative taxonomy in the context of species delimitation is also discussed.

Artificial Feeding of All Consecutive Life Stages of Ixodes ricinus

The hard tick Ixodes ricinus is an obligate hematophagous arthropod and the main vector for several zoonotic diseases. The life cycle of this three-host tick species was completed for the first time in vitro by feeding all consecutive life stages using an artificial tick feeding system (ATFS) on heparinized bovine blood supplemented with glucose, adenosine triphosphate, and gentamicin. Relevant physiological parameters were compared to ticks fed on cattle (in vivo). All in vitro feedings lasted significantly longer and the mean engorgement weight of F0 adults and F1 larvae and nymphs was significantly lower compared to ticks fed in vivo. The proportions of engorged ticks were significantly lower for in vitro fed adults and nymphs as well, but higher for in vitro fed larvae. F1-females fed on blood supplemented with vitamin B had a higher detachment proportion and engorgement weight compared to F1-females fed on blood without vitamin B, suggesting that vitamin B supplementation is essential in the artificial feeding of I. ricinus ticks previously exposed to gentamicin.

Lockdown effect of the brown dog tick with-in a bamboo sticky trap using sustained release pheromone beads in kennels

ABSTRACT Ticks are ubiquitous in nature and have considerable medical and veterinary importance. They act as vectors for a diverse array of pathogens affecting animals and humans. Rhipicephalus sanguineus is the most prevalent species infesting the dogs in Tamil Nadu. Control of this three-host tick mainly depends on the use of acaricides, with attendant problems of development of acaricidal resistance in ticks and possibility of drug residues. In the current study, pheromones were evaluated as an alternative substance for control of the dog tick. Optimal concentration of attractant sex pheromone (ASP), assembly pheromone (AP), and combination of both ASP and AP were encapsulated using calcium alginate beads for sustained release of pheromones. Bamboo sticky traps were designed as a platform to hold these pheromone encapsulated beads. Field trials were conducted using these pheromone lures as bait in the bamboo trap. Field trials revealed that AP encapsulated calcium alginate beads lured the maximum number of different stages of dog ticks. Thus, a bamboo trap with AP encapsulated calcium alginate beads can be used in integrated pest management along with other routine practices for control of dog tick in kennels. Statistical analysis by chi-square test revealed that there was a highly significant (p < 0.01) difference in the level of attraction between engorged and questing stages of ticks to the pheromones in the trap.

Біологічні та морфологічні особливості іксодових кліщів західного регіону України

Ticks of the family Ixodidae are widespread in Central Europe, belong to the group of three-host ticks and play an important role in agriculture, among domestic animals and in the epidemiological well-being of humans. The study of ticks D. reticulatus and I. ricinus was carried out in Khmelnytsky, Chernivtsi, Vinnytsia and Ternopil regions, in 12 cities and eight districts. In addition, monitoring was carried out in the administrative centers of the regions at certain points. During three years (2018–2020) 3768 Ixodid ticks were collected: 2784 D. reticulatus (1719 females, 886 males, 142 larvae, 37 nymphs) and 984 I. ricinus (508 females, 367 males, 93 larvae, 16 nymphs), 4830 animals were examined in Khmelnytsky, Chernivtsi, Vinnytsia and Ternopil regions. The life cycle of I. ricinus ticks usually took three years. Their greatest peak, as a rule, occurred in spring and early summer, with the second active period in autumn in some districts of Khmelnytsky and Ternopil regions during all three years. During the study of D. reticulatus ticks observed the emergence of abundant populations of ticks in open, non-urban areas, which were found on the outskirts of villages, in abandoned areas, pastures and forests. The life cycle of ticks was one or two years, depending on environmental conditions. Ticks of this species were more common in cold areas with sufficient relative humidity. The main period of activity of adults was spring, with a secondary peak in autumn, but the dynamics varied significantly depending on the region. Morphological abnormalities in ticks were detected during the research.

Questing by Tick Larvae (Acari: Ixodidae): A Review of the Influences That Affect Off-Host Survival.

Questing is a host-seeking behavior in which ticks ascend plants, extend their front legs, and wait poised for a chance to attach to a passing host. Hard ticks are ectoparasites of terrestrial vertebrates and because some species vector disease, they are among the most medically important of arthropod pests. All ixodid ticks require blood to survive and reproduce with the number of blood-hosts needed to complete their life cycle varying among species. The vast majority are three-host ticks requiring a different host for each developmental stage: larva, nymph, and adult. A few, including some of the most economically important species, are one-host ticks, that quest only in the larval stage. Questing is a rate-limiting behavior critical to tick survival and disease transmission. For the off-host larval stage, survival is highly dependent on ecological and physiological factors. Yet, off-host larval ecophysiology is often overlooked for the more obvious adult and nymphal tick-host interactions. This review summarizes the literature on ixodid larval questing with emphasis on how specific biotic and abiotic factors affect off-host survival.

Analysis of microRNA expression profiles dynamic in different life stages of Haemaphysalis longicornis ticks by deep sequencing of small RNA libraries

The three-host tick Haemaphysalis longicornis is an obligate blood-sucking ectoparasite. In life-stage transitions, microRNAs (miRNAs) show a variety of expression changes. To investigate these changes, deep sequencing technology was applied to identify the conserved and potentially novel miRNAs expressed during the different life stages of H. longicornis. Total RNA from eggs, unfed larvae, unfed nymphs and unfed adults was extracted for deep sequence analysis. Deep sequencing on a Hiseq 4000 generated a total of 111,192,069 reads, grouped into four small RNA (sRNA) libraries, one for each of the four developmental stages of H. longicornis. Among these sequences, 78 conserved and 55 potentially novel miRNAs were identified, including stage-specific and differentially expressed miRNAs. Gene ontology (GO) analysis indicated significantly enriched GO terms related to cell proliferation and differentiation, including specific terms for the processes of development, growth, metabolism, regulation of biological functions, reproduction, and membrane enzyme regular activity. Kyoto Encyclopedia of Gene and Genomes (KEGG) analysis revealed a significant enrichment of the insulin, notch, Hippo, and Wnt signaling pathways for growth and development. Our data highlight the abundance of miRNA changes (conserved and potentially novel) in the different life stages of H. longicornis. In particular, stage-specific miRNAs, as observed, are essential regulators for the development of H. longicornis.

Asian longhorned tick, Haemaphysalis longicornis Neumann (Arachnida: Acari: Ixodidae)

The Asian longhorned tick, Haemaphysalis longicornis Neumann, also known as the longhorned tick, bush tick (Australia), and cattle tick (New Zealand), is a three-host tick native to East Asia. This tick has been categorized as an invasive species in Australia, New Zealand, and several Pacific Islands. In the U.S., an Asian longhorned tick infestation was recorded in New Jersey during the fall of 2017. This tick is somewhat unique in that females are capable of parthenogenesis, meaning that females can produce offspring without having mated with males. The Asian longhorned tick feeds on a wide range of hosts including birds and mammals, including humans. This tick is considered a medical and veterinary vector due to its ability to transmit pathogens that cause disease in humans and other animals.https://edis.ifas.ufl.edu/in1263

Exotic Haemaphysalis longicornis (Acari: Ixodidae) in the United States: Biology, Ecology, and Strategies for Management

Abstract The Asian longhorned tick (ALT), Haemaphysalis longicornis Neumann (Acari: Ixodidae), is a three-host tick that was first detected outside of United States Department of Agriculture (USDA) quarantine in Hunterdon County, New Jersey, in 2017 and subsequently found in another 14 states. In its native Asia, and where it has become established in Australia and New Zealand, ALTs feed on a variety of hosts and are economically important livestock pests and competent vectors of multiple pathogens to humans and other animals. The degree to which ALT will become a persistent livestock pest or competent vector for introduced or existing pathogens in the United States is yet unclear. Because of its vast host availability, ability to reproduce asexually, known vector competence, and the presence of multiple life stages on hosts, the expansion of ALT establishment in the United States is expected, and is a significant public health and veterinary concern. In this paper, we discuss the biology, geographical distribution, life cycle and seasonal activity, reproduction, identification, medical and veterinary implications, management options, and future concerns in the United States.