Paralysis in chickens caused by larvae of the poultry tick, Argas persicus

White Leghorn pullets 20 weeks old submitted to the diagnostic laboratory were found heavily infested with the larval stage of the poultry tick, Argas persicus. The birds were severely depressed and recumbent. The signs were quickly reversed when the tick larvae were removed. The rapid rate of recovery and negative results in detailed diagnostic procedures suggested that the tick larvae caused the paralysis.