Flock and Herd logo

CASE NOTES

A case of paresis in backyard poultry suspected to be caused by Argas persicus (Fowl Tick)

Alicia Moses, District Veterinarian Central West LLS

Posted Flock and Herd March 2026

Introduction

Argas persicus, colloquially known as the fowl or poultry tick, is found worldwide and was introduced to Australia decades ago with imported domestic poultry. They are part of the Argasidae family (soft ticks) which are distinguished from Ixodidae (hard ticks) by their wrinkled leathery appearance and small mouthparts. The larvae, nymphs and adults parasitise domestic poultry, with chickens being the most susceptible, however domestic turkeys, ducks, pigeons and other cage birds are also at risk of infestation. They are a particular issue in the poultry industry as they can cause significant production loss, morbidity and mortality. This report describes a case of a chicken with an A. persicus infestation with paresis as the main clinical presentation.

History

In January 2021, the author found an Old English Game bantam hen in a personal backyard flock with marked paresis. The property was located within the Riverina and the poultry flock had been on the property for approximately six months. The chickens roosted in a wooden coop at night and had access to an outside run during the day. The chickens were bred for poultry exhibition and the eggs and meat were not used for human consumption.

Clinical examination

The hen was found in a sitting position and had difficulty getting up when approached, tending to move on her hocks. She could stand with assistance and take a few weak steps before sinking down again. She had dried blood and mild abrasions to the back of her head and neck, which were attributed to aggression from other pen mates. Otherwise, she was bright and alert with a red comb and face.

Many tiny sucking parasites in clusters were found on bare skin under the wings, the thigh and peri-vent areas. The parasites were blue-black, oval-shaped and approximately 2-3mm diameter. There were subcutaneous haematomas deep to where the parasites were attached (Figures 1 and 2).

Although not examined microscopically at the time, the parasites are suspected to be the larval stage of A. persicus.

Outcome

The ticks were removed by hand, and off-label ivermectin (Ivomec 5mg/ml, Boeringher Ingelheim) was applied topically. The hen made a full recovery within a few days with no long-lasting effects. The remaining poultry in the flock were examined grossly for ticks and moved to a fresh coop while the affected coop was treated with an acaricide.

Over the next few years, small numbers of chickens were infested with the ticks during spring and summer despite environmental control attempts, with a few mortalities due to complete paralysis, anaemia or possibly secondary infections. The coops were instead used to house less-susceptible poultry such as ducks, and no further cases have occurred since.

Image of tick larvae on chicken skin
Figure 1. Suspected larvae of A. persicus with subcutaneous haematomas on the thigh
Image of subcutaneous haematomas under wing on a chicken
Figure 2. Subcutaneous haematomas under the wing (ticks had been removed)

Discussion

Infestation with A. persicus may go unnoticed due to their ability to feed within minutes to hours and detach from the host to moult. The exception is the larvae, which remain attached for 5-10 days, most commonly on sparsely feathered skin under the wing. Clinical signs may be non-specific and include depression, weight loss, pale comb and decreased egg production. Prolonged infestations can result in more serious disease through anaemia, paralysis and secondary infections.

Each tick is reported to suck 18.57mg of blood per day (Khan et al. 2001). With an estimated blood volume of 6-7.5% of body weight, a 1kg bantam chicken would have approximately 70g of blood. Prolonged exposure to ticks or heavy infestations are therefore needed for clinical anaemia to develop. Mortalities due to marked anaemia were reported to begin approximately 2-3 weeks after experimentally exposing chickens to A. persicus in a recent study (Alzahrani & Edrees 2020). The salivary glands of A. persicus are thought to contain anticoagulants, which combined with vascular damage from the tick bite, result in localised subcutaneous haemorrhage and haematomas (Hobbenaghi et al. 2015; Mallesh et al. 2017). Haematocrit was not assessed in this hen, however the red face and comb would suggest clinically significant anaemia had not yet developed.

Marked paresis was the primary clinical sign in this case. Differential diagnoses for paresis and paralysis in chickens include Marek's Disease, Newcastle disease, Avian Encephalomyelitis, Avian Influenza, botulism, spinal cord trauma, rickets, thiamine deficiency, heavy metal toxicity and avian spirochaetosis. Paralysis by A. persicus can be primary through neurotoxins in their saliva, or secondary from the effects of Borrelia anserina, a spirochete that A. persicus can transmit. Avian spirochaetosis most commonly causes an enteritis and green diarrhoea, with paralysis potentially developing in the later stages of infection (Behboudi 2022). In this case, the hen did not develop gastrointestinal or other signs of spirochaetosis and made a full, rapid recovery with tick removal alone. This finding would suggest that the paresis was a direct effect from the A. persicus infestation, which was also found to be the case in a recent study with a similar clinical presentation (Salavati et al. 2025). Overseas studies report 5.9-27.2% prevalence of B. anserina in A. persicus life stages, however similar studies in Australia have not been done (Ouchene et al. 2020; Aslam et al. 2015; Zahid et al. 2017).

A. persicus prefers hot, humid environments, which are not typical of the Riverina region. However, the summer of 2021 was particularly wet, which would have favoured A. persicus survival and replication. It is generally recommended to treat the environment with an acaricide for control. However, ticks will hide in cracks and crevices, and the adult tick can survive for up to three years without a blood meal, making them difficult to totally eradicate.

There are very few products registered in poultry that target ticks. Maldison (Malathion), an organophosphate, is one such product that is registered in Australia, however there are serious environmental, animal and human health concerns with its use. Oral ivermectin was shown to be 82.96% effective against A. persicus three weeks post-treatment (Khan et al. 2001). Withholding periods (WHP) are an important consideration for veterinarians when using and prescribing products such as ivermectin off-label in food-producing species. Ivermectin is highly lipid-soluble and has been found to accumulate in fat and egg yolks (Goetting et al. 2011). Ivermectin residues in egg-yolks were found to be dose-dependent and were detectable for over six days following cessation of treatment in laying hens at 0.8mg/kg oral dose rate (Keukens et al. 2000). Veterinarians should ensure poultry owners are aware that eggs and meat should not be sold for human consumption following treatment until the pre-determined WHP has expired.

As an aside, with the recent release of fluralaner (Exzolt, MSD Animal Health) as an approved control of red mites and northern fowl mites in poultry, the efficacy of this drug on Argasid ticks needs to be determined as good control has already been demonstrated against many Ixodid ticks in other species.

As always, the importance of biosecurity and maintaining a closed flock should be emphasised to poultry owners. Prophylactic internal and external parasite treatments and an adequate quarantine period should be utilised for any introductions to a flock. This study also demonstrates how a thorough physical exam in poultry can lead to a simple yet life-saving diagnosis.

References

  1. Alzahrani AM and Edrees NO (2020) Effect of the fowl tick Argas persicus (Oken, 1818)(Acari: Argasidae) infestation on the health of Baladi chicken in Jeddah, Saudi Arabia Journal of Animal Health and Production 8 pp 13-18
  2. Aslam B, Hussain I, Zahoor MA, Mahmood MS and Rasool MH (2015) Prevalence of Borrelia anserina in Argas Ticks Pakistan Journal of Zoology 47(4) pp 1125-1131
  3. Behboudi S (2022) Borrelia anserina infections CABI Compendium
  4. Goetting V, Lee KA and Tell LA (2011) Pharmacokinetics of veterinary drugs in laying hens and residues in eggs: a review of the literature Journal of veterinary pharmacology and therapeutics 34(6) pp 521-556
  5. Hobbenaghi R, Tavassoli M, Allymehr M, Nasiry S and Pashaie B (2015) Pathological study of experimentally induced tick bitten (Argas persicus) in poultry skin Iranian Journal of Veterinary Science and Technology 7(2) pp 1-8
  6. Khan MN, Khan LA, Mahmood S and Qudoos A (2001) Argas persicus infestation: prevalence and economic significance in poultry Pakistan Journal of Agricultural Sciences 38 pp 32-34
  7. Khan LA, Khan MN, Iqbal Z and Qudoos A (2001) Comparative acaricidal efficacy of cypermethrin, ivermectin, trichlorphon and Azadirachta indica (neem) in layers naturally infested with Argas persicus Pakistan Journal of Agricultural Sciences 38 pp 29-31
  8. Keukens HJ, Kan CA, Van Rhijn JA and Van Dijk J (2000) Ivermectin residues in eggs of laying hens and in muscle and liver of broilers after administration of feeds containing low levels of ivermectin Proceedings of the EuroResidue IV Conference, Veldhoven, The Netherlands
  9. Mallesh P, Manchukonda UK and Murthy GS (2017) Studies on the salivary glands of Argas persicus The Pharma Innovation 6(7 Part C) pp 180-184
  10. Ouchene N, Nebbak A, Ouchene-Khelifi NA, Dahmani A, Zeroual F, Khelef D, Bitam I, Benakhla A and Parola P (2020) Molecular detection of avian spirochete Borrelia anserina in Argas persicus ticks in Algeria Comparative Immunology, Microbiology and Infectious Diseases 68 p 101408
  11. Salavati A, Sharifi_Moghadam A, Riahi A, Shakouri M, Arabkhazaeli F and Razmyar J (2025) Case Report Tick Paralysis Caused by Argas persicus Infestation in Domestic Chickens: A Case Report Iranian Journal of Veterinary Medicine 19(3) pp 599-604
  12. Zahid H, Alouffi A, Almutairi MM, Ateeq M, Tanaka T, Chang SC, Chen CC and Ali A (2023) Argas persicus and Carios vespertilionis ticks infesting ducks, domestic fowls and bats in Pakistan: first report on molecular survey and phylogenetic position of Borrelia anserinaVeterinary Sciences 10(10) p 628

 

Site contents Copyright 2006-2026©