Aspectos epidemiológicos de Megninia spp (Acari: Analgidae) e malófagos (Insecta: Phthiraptera) na avicultura de postura de Minas Gerais (2012)

Abstract

The present work presents aspects related to the epidemiology of infestations by mites belonging to genus Megninia and of Mallophaga, aiming determine the predisposing factors for the occurrence of these ectoparasites in commercial layer hens farms in the State of Minas Gerais. Thus, an observational, cross-sectional and analytical study was conducted. Samples of feathers, ectoparasites and manure were collected in order to perform the detection and identification of species and taxa. The inspection of facilities and the application of a questionnaire validated by a test-retest procedure were performed. The questionnaire had 89 questions alternatives of objective and categorical questions. The verification of the epidemiological aspects was done using multiple logistic regression models or Poisson regression models, which were selected according to the frequency of occurrence of ectoparasites. Four hundred thirty-one chicken houses were visited in 43 farms in 2012, and the rates of occurrence of these ectoparasites were very diverse and apparently have values close to the actual prevalence rates. Megninia ginglymura and Megninia cubitalis were observed in approximately 39.53% and 2.32% of poultry farms. The frequencies of Lipeurus caponis, Menacanthus cornutus, Menacanthus pallidulus, Menacanthus stramineus and Menopon gallinae were 4.65%, 20.93%, 11.62%, 11.62% and 2.32%, respectively. Co-infestations of louse species were observed in many chicken houses. Other arthropods such as manure mites, beetles and Dermaptera and Diptera insects were also observed. The presence of subsistence poultry in the vicinity of the poultry farms was considered a predisposing factor for the occurrence of infections by M. ginglymura, L. caponis and M. pallidulus. Mineral oil was classified as a protective factor against infestation by M. ginglymura. Regarding L. caponis, the predominant lineage of chickens and the type of installation were considered risk factors. The presence of synanthropic birds such as Guira cuckoo (Guira guira), Saffron-finch (Sicalis flaveola) and pigeons (Coumba livia) were considered predisposing factors for the occurrence of infections by M. cornutus, although it is a specificous parasite of domestic chicken. The use of of acaricides was considered a protective factor against this parasite. Older hens and houses with greater density of chickens have greater chances of presenting infestations by M. stramineus, as well as presence of Chopi blackbird (Gnorimopsar chopi) and Guira Cuckoo in the vicinity was demonstrated. The presence of Cattle Egret (Bubulcus ibis) and type of house facility also influenced the occurrence of M. pallidulus. Multivariate models demonstrated that some of the regions of the State of Minas Gerais were considered risk or protection areas for the occurrence ectoparasites, mainly due to different climatic conditions and other factors not assessed in this study.