Merck Manual

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Professional Version

Argas spp


Michael L. Levin

, PhD, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention

Reviewed/Revised Aug 2020 | Modified Nov 2022

Most of the 57 known Argas spp are specific for birds or bats; a few parasitize wild terrestrial mammals or Galapagos giant tortoises. A persicus (the fowl or poultry tick) is an important poultry pest worldwide in warm climates. A persicus thrives in poultry houses and chicken coops. Heavy infestations and frequent bites of this tick can lead to secondary infections, anemia, weakness, and weight loss in birds. A persicus are most active during warm, dry weather. The adults and nymphs feed at night and hide in cracks, crevices, or under debris during the day; larvae remain attached to birds for 2–7 days. Likewise, A reflexus can cause severe blood loss in pigeons. A miniatus (the South American chicken tick) and A radiatus (the North American bird tick) can present a problem for traditional or outdoor poultry operations from the Caribbean to Central America and from the Caribbean to North America, respectively. The species of importance in transmitting Aegyptianella pullorum Aegyptianellosis in Poultry Aegyptianellosis is an acute, tickborne, febrile disease caused by Aegyptianella spp, a rickettsia in the family Anaplasmataceae. Infection of avian species, including chickens, turkeys... read more and Borrelia anserina Avian Spirochetosis Avian spirochetosis is an acute bacterial infection transmitted by tick to a wide range of birds. Clinical signs are highly variable and generally nonspecific. Diagnosis requires identifying... read more to poultry are A persicus (many tropical and subtropical areas of the world), A arboreus (much of Africa, including Egypt), A africolumbae (tropical Africa), A walkerae (southern Africa), and A miniatus (South and Central America). Other species that infest poultry appear to transmit both A pullorum and B anserina. (Also see Fowl Ticks Fowl Ticks The fowl tick, Argas persicus, is found worldwide in tropical and subtropical countries and is the vector of Borrelia anserina ( avian spirochetosis) and the rickettsia Aegyptianella... read more .) Tick paralysis Tick Paralysis in Animals Tick paralysis (also known as tick toxicosis) is an acute, progressive, symmetrical, ascending motor paralysis due to salivary neurotoxins produced by certain species of ticks. With some species... read more is caused by feeding A persicus, A arboreus, A walkerae, A miniatus, A radiatus, and A sanchezi (USA). These and other Argas spp can cause great irritation when feeding on people.

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