title: Reappearance of Mecistocirrus digitatus in cattle from the Mexican tropics: prevalence, molecular, and scanning electron microscopy identification.
abstract: Mecistocirrus digitatus is a hematophagous abomasal nematode which causes significant blood and production losses in cattle. The objectives of the present study were to: (1) report the reappearance of M. digitatus in cattle from the Mexican tropics using microscopy, scanning electron microscopy (SEM), and molecular identification, and (2) determine the prevalence of M. digitatus in slaughtered adult cattle from the Mexican tropics. Gastroinestinal nematodes (GIN) were recovered from the abomasum of an 8-yr-old cow (Holstein × Zebu) previously diagnosed with Johne's disease. Of 1,254 GIN, 98.8% were identified as M. digitatus and 1.2% as Haemonchus sp. SEM was used to identify ultrastructure features of M. digitatus (oral cavity, cervical papillae, bursa, bursa lobes papillae, male spicules, anus, and female vulva). A conventional PCR method was used to corroborate the morphological findings. The prevalence of adult cattle infected with M. digitatus and Haemonchus sp., determined from 68 adult cattle from different grazing tropical herds, was 38.2% and 8.8%, respectively. Ninety-eight percent of animals infected with M. digitatus presented lesions in their abomasum such as mucosal inflammation, hemorrhage, and ulcers; some of them had necrosis. The current reappearance of M. digitatus in a Mexican herd suggests the possibility of an underestimated prevalence of this nematode amongst grazing cattle.
authors.affiliation: Centro de Enseñanza Investigación y Extensión en Ganadería Tropical, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Km 5.5 Carretera Federal Tlapacoyan-Martínez de la Torre, C.P. 93600, Veracruz, México.
authors.forename: Elke
authors.initials: E
authors.lastname: von Son-de Fernex
authors.forename: Miguel Ángel
authors.initials: MÁ
authors.lastname: Alonso-Díaz
authors.forename: Pedro
authors.initials: P
authors.lastname: Mendoza-de-Gives
authors.forename: Braulio
authors.initials: B
authors.lastname: Valles-de la Mora
authors.forename: Enrique
authors.initials: E
authors.lastname: Liébano-Hernández
authors.forename: María Eugenia
authors.initials: ME
authors.lastname: López-Arellano
authors.forename: Liliana
authors.initials: L
authors.lastname: Aguilar-Marcelino
mesh_terms: D000018:Abomasum / Q000469:parasitology; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000469:parasitology*; D018509:DNA, Helminth / Q000737:chemistry / Q000302:isolation & purification; D005260:Female; D006188:Haemonchiasis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D015995:Prevalence; D018510:RNA, Helminth / Q000235:genetics; D016415:Sequence Alignment / Q000662:veterinary; D014251:Trichostrongyloidea / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D014252:Trichostrongyloidiasis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D014329:Tropical Climate
chemical_list: D018509:DNA, Helminth; D018510:RNA, Helminth