Identification of factors influencing the occurrence of milk spot livers in slaughtered pigs: A novel approach to understanding Ascaris suum epidemiology in British farmed pigs

Abstract

Ascariosis is the most important internal parasitism present worldwide in farmed pigs. Milk spots are healing lesions occurring when Ascaris suum larvae migrate through the liver. This study aimed to identify current husbandry practices (e.g. wet/compound feeding, outdoors/indoors production, bedded/slatted floors) that influence the prevalence of milk spots in batches of slaughtered pigs, accounting for geographical locations and seasonality. Farm information was accessed through the British farm quality assurance programmes (QAPs) and information on milk spots was obtained from the pig abattoir based health schemes. Two working datasets were created. The first consisted of 505 farms recruited from the whole of Great Britain (GB). The second combined 338 farms from England and Wales (EW) with housing and feed category-specific information (e.g. for growers and finishers separately), which was not fully available for inclusion in the previous dataset. The variables were studied in multivariable beta-binomial models with the presence of milk spots being the response variable. Solid floor with bedding appeared as a risk factor, OR 1.52 (95% confidence intervals (CI) 1.26-1.85) for the GB sample, and OR 1.47 (CI 1.19-1.81) for the EW subset. Those GB herds that had all the stages of production indoors appeared to be at lower risk of milk spots (OR 0.4, CI 0.32-0.49). Changes were detected within year, with higher risk of milk spots in the second 6 months of the year OR 1.17 (CI 1.02-1.35) in the GB sample and 1.21 (95% CI 1.04-1.41) in EW farms. Overall this study suggests that those husbandry practices facilitating optimal levels of hygiene posed lower risk of milk spots in slaughtered pigs, potentially reflecting lower levels of ascariosis in the later stages of production.

Parasitas Intestinais Encontrados Em Suíno Abatido Em Matadouro De Inspeção Municipal - Um Estudo De Caso

“…A migração das larvas de Ascaris suum pelos pulmões pode causar pneumonia, e quando associadas a agentes oportunistas, pode agravar o quadro clínico geral e resultar na morte do animal (VAZQUEZ et al, 2010). Não foi perceptível a presença de alterações pulmonares no animal deste caso.…”

Zoonotic Ascariasis, United Kingdom

“…However, standard resistance testing cannot detect drug-resistant HIV-1 minority variants unless they represent 20%-25% of the population (2). Approximately 15% of those who underwent seroconversion in the acute phase in industrialized settings harbor drug-resistant HIV-1 minority variants, while standard resistance testing did not detect drug-resistant viruses in those patients (3). We report the case of a treatment-naive HIV-1-infected patient with early treatment failure because of preexisting minority K65R-harboring HIV-1 variants.…”

“…In industrialized countries, human ascariasis is uncommon and cases are generally believed to have been imported (2). By contrast, A. suum infection of pigs occurs worldwide; in the United Kingdom, 3.4%-6.5% of pigs at slaughter have evidence of infection (3). Sporadic zoonotic infection with A. suum in the industrialized world is described (4-6) but poorly quantifi ed.…”

Ascaris suum in pigs of the Zona da Mata, Minas Gerais State, Brazil

“…These programs are aimed at determining the prevalence and epidemiology of the parasite in the herd, based on the detection of milk spots on the liver of slaughtered animals (SANCHEZ-VAZQUEZ et al, 2010;BOES et al, 2010). The findings are systematically passed on to producers as a strategy to encourage control of the parasite in the herd (SANCHEZ-VAZQUEZ et al, 2012).…”

“…Sanchez-Vazquez et al (2010) recently demonstrated that infection by this parasite can decrease the animal's daily weight gain by up to 10%, and the feed conversion of pigs by up to 13% in the growing phase and at slaughter. A high occurrence of the parasite has also been reported in the herds of several countries, such as Slovakia, England and Poland (ČERNEK et al, 2012;SANCHEZ-VAZQUEZ et al, 2012;KNECHT et al, 2012).…”