Influence of environmental factors on the detection of blood in sheep faeces using visible–near-infrared spectroscopy as a measure of Haemonchus contortus infection

Autor: Anne Beasley, Peter J. James, Glen P. Fox, Stephen S. Moore, Maggy T. Sikulu-Lord, Jill N. Fernandes, Andrew C. Kotze, Elise A. Kho
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Veterinary medicine
Mycology & Parasitology
Visible–near infrared spectroscopy
01 natural sciences
Faecal analysis
Feces
Hemoglobins
Haemonchus contortus
Partial least squares regression
Near-Infrared
Anthelmintic
Spectroscopy
screening and diagnosis
Principal Component Analysis
Spectroscopy
Near-Infrared
biology
Visible near infrared
Age Factors
04 agricultural and veterinary sciences
Detection
Visible-near infrared spectroscopy
Infectious Diseases
Blood
Hematocrit
Medical Microbiology
Occult Blood
Principal component analysis
Public Health and Health Services
Female
Queensland
Haemoglobin
New South Wales
medicine.drug
Gastrointestinal nematodes
Sheep Diseases
Environment
010309 optics
Tropical Medicine
0103 physical sciences
medicine
Animals
Sheep
Research
0402 animal and dairy science
biology.organism_classification
040201 dairy & animal science
4.1 Discovery and preclinical testing of markers and technologies
Blood chemistry
Parasitology
Flock
Haemonchiasis
Zdroj: Parasites & Vectors
Parasites & vectors, vol 13, iss 1
ISSN: 1756-3305
Popis: BackgroundExisting diagnostic methods for the parasitic gastrointestinal nematode,Haemonchus contortus, are time consuming and require specialised expertise, limiting their utility in the field. A practical, on-farm diagnostic tool could facilitate timely treatment decisions, thereby preventing losses in production and flock welfare. We previously demonstrated the ability of visible–near-infrared (Vis–NIR) spectroscopy to detect and quantify blood in sheep faeces with high accuracy. Here we report our investigation of whether variation in sheep type and environment affect the prediction accuracy of Vis–NIR spectroscopy in quantifying blood in faeces.MethodsVisible–NIR spectra were obtained from worm-free sheep faeces collected from different environments and sheep types in South Australia (SA) and New South Wales, Australia and spiked with various sheep blood concentrations. Spectra were analysed using principal component analysis (PCA), and calibration models were built around the haemoglobin (Hb) wavelength region (387–609 nm) using partial least squares regression. Models were used to predict Hb concentrations in spiked faeces from SA and naturally infected sheep faeces from Queensland (QLD). Samples from QLD were quantified using Hemastix® test strip and FAMACHA© diagnostic test scores.ResultsPrincipal component analysis showed that location, class of sheep and pooled versus individual samples were factors affecting the Hb predictions. The models successfully differentiated ‘healthy’ SA samples from those requiring anthelmintic treatment with moderate to good prediction accuracy (sensitivity 57–94%, specificity 44–79%). The models were not predictive for blood in the naturally infected QLD samples, which may be due in part to variability of faecal background and blood chemistry between samples, or the difference in validation methods used for blood quantification. PCA of the QLD samples, however, identified a difference between samples containing high and low quantities of blood.ConclusionThis study demonstrates the potential of Vis–NIR spectroscopy for estimating blood concentration in faeces from various types of sheep and environmental backgrounds. However, the calibration models developed here did not capture sufficient environmental variation to accurately predict Hb in faeces collected from environments different to those used in the calibration model. Consequently, it will be necessary to establish models that incorporate samples that are more representative of areas whereH. contortusis endemic.Graphical Abstract
Databáze: OpenAIRE
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