This study was conducted in order to identify the species of biting lice (order Phthiraptera: Amblycera suborders and Ischnocera) that infest free-range chickens in southern Rio Grande do Sul, Brazil. Fifty adult females from 10 farms located in 5 different municipalities were examined for ectoparasites. The chickens were euthanized and then washed with water and detergent for the collection of ectoparasites by filtration using a 150-µm mesh sieve, then separated into pellet and supernatant, which were preserved in ethanol 70% for the screening procedures and identification. A total of 19,437 lice were examined, presenting the following breakdown by species: Menopon gallinae (85.9%), Goniodes dissimilis (6.1%), Lipeurus caponis (3.0%), Goniocotes gallinae (2.5%), Menacanthus pallidus (2.1%) and Menacanthhus stramineus (0.1%). It was found that all the chickens examined were parasitized by one or more species of Phthiraptera, the multiple and moderate level of infestation (101 to 1,000 lice/chicken) being the most frequent. M. gallinae was the most frequent and abundant species (100% of the chickens parasitized and an average of 334.1 lice/chicken). The degree of infestation of chickens varied among the farms, averaging 41.2 to 680 lice/chicken.
Biting lice; Phthiraptera; free-range chickens; Rio Grande do Sul State