Canis ISSN: 2398-2942

Haemaphysalis longicornis

Synonym(s): Asian longhorned tick, ALT, longhorned tick, busk tick, cattle tick, New Zealand cattle tick, scrub tick

Contributor(s): Peter Irwin, Gad Baneth

Introduction

Classification

Taxonomy

  • Phylum: Arthropoda 
  • Class: Arachnida 
  • Order: Ixodida 
  • Family: Ixodidae 
  • Genus: Haemaphysalis 
  • Species: H. longicornis 

Active Forms

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Resting Forms

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Clinical Effects

Epidemiology

Habitat

  • A wide variety of environmental conditions and temperatures (from -2°C to 40°C) have been found to support this tick, from moist, warm regions in Australia, New Guinea and the western Pacific islands, to cooler northern latitudes in the northern hemisphere (China, Japan) and southern parts of Australia and New Zealand. Different tick populations are adapted to warm or cold regions. 
  • Long periods of the tick’s life cycle are spent off the hosts within the environment in vegetation, molting and waiting for a suitable host. 
  • In New Zealand, H. longicornis ticks prefer Dallas grass (Paspalum dilatatum) and rushes (Juncus spp.) and areas with unmown grass and manicured lawn have also been found suitable in the US. 
  • Ticks are attracted to a vertebrate host by a combination of its body warmth and exhaled carbon dioxide. Active forms climb the vegetation, transferring to the host on contact as it passes by. 
  • Ticks survive in woodlands and other uncultivated areas, pastures and in residential areas. 

Lifecycle

  • Tick activity, survival and abundance is influenced by the integration of temperature, humidity, photoperiod and host availability. 
  • In general, the principal seasonal activity of unfed females is in early spring, larvae are active in the summer and nymphs and females are the main overwintering stages, however overlapping of the life stages occurs in some regions. 
  • The period of seasonal activity depends predominantly on the environmental temperature (and is therefore related to latitude). Southern hemisphere populations have activity periods of 10-11 months, which is similar in Korea, but the further north H. longicornis populations are found (in the northern hemisphere) generally the shorter is the seasonal activity period (eg 4 months [June to September] at 43°N on mainland Japan). 
  • Haemaphysalis longicornis is a three-host tick (each stage falls off the host into the environment after feeding, molts, and finds another host for the next stage). 
  • Engorged female ticks can produce viable eggs after mating (sexual reproduction) or (in triploid races) without the need for mating with a male (asexual) - a process known as parthenogenesis. 
  • Immature life stages (larvae and nymphs) are usually found on smaller hosts (eg hares, rodents, goats), adults frequently on larger mammals (eg cattle, deer), however the tick attaches and feeds successfully on multiple species of domesticated and wild mammals, birds, and humans. 

Pathological effects

  • Like with other tick species, heavy infestations of H. longicornis in cattle, horses, sheep and dogs may cause worry, dermatopathies, and blood loss anemia. 
  • Transmission of pathogens, including: 
    • Bovine theileriosis (Theileria orientalis). 
    • Babesia spp Babesia spp (especially Babesia gibsoni in dogs and Babesia ovata in cattle). 
    • Coxiella burnetii Coxiella burneti (the agent of coxiellosis in animals and Q fever in humans). 
    • Rickettsia japonica (zoonosis: Japanese spotted fever).
    • Severe Fever with Thrombocytopenia Syndrome virus (SFTSV) (bunyavirus zoonosis).
  • DNA of the following pathogens has been detected in H. longicornis (transmission not proven): 

Other Host Effects

  • Development of mammalian meat allergy (MMA) with reaction to the alpha-gal allergen in humans has been attributed to the bite of Haemaphysalis longicornis in Japan. 

Control

Control via chemotherapies

  • Large animals (eg cattle, horses) are treated with pour-on (topical) acaricides or dips (cattle), however because ticks feed for a short time and spend long periods off the host, reliance on acaricides alone to reduce tick numbers and exposure to theileriosis is not a reliable management option. 
  • Agents that have been successfully tested for efficacy against H. longicornis in dogs include: 

Control via environment

  • Difficult to achieve with success and without use of acaricides and potential environmental contamination. 
  • For cattle (and to reduce the incidence of theileriosis) pasture management (keeping grass short or removing ticks using low-value stock) is recommended. 

Vaccination

  • None available.

Diagnosis

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Pritt B S (2020) Haemaphysalis longicornis in in the United States and biting humans: Where do we go from here? Comm Infect Dis 70, 317 PubMed
  • Thompson A T, Dominguez K, Cleveland C A, Dergousoff S J, Doi K, Falco R C, Greay T, Irwin P, Lindsay L R, Liu J, Mather T N, Oskam C L, Rodriguez-Vivas R I, Ruder M G, Shaw D, Vigil S L, White S & Yabsley M J (2020) Molecular Characterization of Haemaphysalis Species and a Molecular Genetic Key for the Identification of Haemaphysalis of North America.Front Vet Sci7, 141 PubMed
  • Rainey T, Occi J L, Robbins R G, Egizi A (2018) Discovery of Haemaphysalis longicornis (Ixodida: Ixodidae) parasitizing sheep in New Jersey, United States. J Med Entomology 55, 757-759 PubMed
  • Heath A C G (2016) Biology, ecology and distribution of the tick, Haemaphysalis longicornis Neumann (Acari: Ixodidae) in New Zealand. New Zealand Vet J 64, 10-20 PubMed.
  • Hoogstraal H, Roberts F S H, Kohls G M, Tipton V J (1968) Review of Haemaphysalis (Kaiseriana) longicornis Neumann (resurrected) of Australia, New Zealand, New Caledonia, Fiji, Japan, Korea and north-eastern China and USSR, and its parthenogenetic and bisexual populations (Ixodoidea, Ixodidae). J Parasitol 54, 1197-1213. 

Other sources of information


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