title: Cutaneous distribution and circadian rhythm of Onchocerca lupi microfilariae in dogs.
abstract: BACKGROUND
  Among the arthropod-borne nematodes infesting dogs, Onchocerca lupi (Spirurida: Onchocercidae) is of increasing zoonotic concern, with new human cases of infection diagnosed in Turkey, Tunisia, Iran and the USA. Knowledge of the biology of this nematode is meagre. This study aimed at assessing the distribution and periodicity of O. lupi microfilariae from different body regions in naturally infested dogs.
  
  
  RESULTS
  Skin samples were collected from six dogs infested with O. lupi but without apparent clinical signs. Two skin samples were collected from 18 anatomical regions of dog 1 at necropsy. In addition, single skin biopsies were performed from the forehead, inter-scapular and lumbar regions of dogs 2-6, in the morning, afternoon, and at night. Two aliquots of the sediment of each sample were microscopically observed, microfilariae counted and morphologically and molecularly identified. Most of the 1,667 microfilariae retrieved from dog 1 were in the right ear (59.6%), nose (26.5%), left ear (6.7%), forehead (3.0%), and inter-scapular (2.9%) regions. In dogs 2-6, the overall mean number of microfilariae was larger on the head (n = 122.8), followed by the inter-scapular (n = 119.0) and lumbar (n = 12.8) regions. The overall mean number of microfilariae was larger in the afternoon (153.4), followed by night (75.4) and morning (25.8).
  
  
  CONCLUSIONS
  Onchocerca lupi microfilariae were more common in the head (i.e., ears and nose) than in the remaining part of the dog's body, indicating they tend to aggregate in specific body regions, which are the best sites to collect skin samples for diagnostic purposes. The periodicity pattern of microfilariae of O. lupi and their concentration in specific body regions is most likely a result of the co-evolution with their as-yet-unknown vector. The detection of skin microfilariae in asymptomatic animals, suggests the potential role of these animals as carriers and reservoirs of O. lupi.
authors.affiliation: Department of Veterinary Medicine, University of Bari, Valenzano, Bari, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Otranto
authors.affiliation: Department of Veterinary Medicine, University of Bari, Valenzano, Bari, Italy ; Department of Immunology, Aggeu Magalãhes Research Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil.
authors.forename: Filipe
authors.initials: F
authors.lastname: Dantas-Torres
authors.affiliation: Department of Veterinary Medicine, University of Bari, Valenzano, Bari, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Giannelli
authors.affiliation: Department of Animal Pathology, University of Pisa, Pisa, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Abramo
authors.affiliation: Faculty of Agriculture, University of Novi Sad, Novi Sad, Serbia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Ignjatović Ćupina
authors.affiliation: Faculty of Agriculture, University of Novi Sad, Novi Sad, Serbia.
authors.forename: Dušan
authors.initials: D
authors.lastname: Petrić
authors.affiliation: Department of Veterinary Sciences, School of Agrarian and Veterinary Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, and Instituto de Biologia Molecular e Celular, Universidade do Porto, Oporto, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Cardoso
authors.affiliation: Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria.
authors.forename: Yasen
authors.initials: Y
authors.lastname: Mutafchiev
authors.affiliation: Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Universidade de Évora, Núcleo da Mitra, Évora, Portugal.
authors.forename: Helder
authors.initials: H
authors.lastname: Cortes
mesh_terms: D000818:Animals; D001706:Biopsy; D002940:Circadian Rhythm; D004283:Dog Diseases / Q000469:parasitology*; D004285:Dogs; D005260:Female; D008297:Male; D008853:Microscopy; D009854:Onchocerca / Q000502:physiology*; D009855:Onchocerciasis / Q000469:parasitology / Q000662:veterinary*; D012867:Skin / Q000469:parasitology*; D012876:Skin Diseases, Parasitic / Q000469:parasitology / Q000662:veterinary*