Bayesian estimation of sensitivity and specificity of fecal culture, fecal PCR and serum ELISA for diagnosis of Mycobacterium avium subsp. paratuberculosis infections in sheep

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Juan Carlos Arango-Sabogal
  • Abdelfattah Selim
  • Kotb A. Attia
  • Roua A. Alsubki
  • Arif M. Mohamed
  • Ameer Megahed

Detail(s)

Original languageEnglish
Article number105712
Journal / PublicationPreventive Veterinary Medicine
Volume206
Online published8 Jul 2022
Publication statusPublished - Sep 2022

Abstract

The objective of the present study was to evaluate the diagnostic accuracy of the individual fecal culture (IFC), fecal PCR (FPCR), and serum ELISA for the detection of Mycobacterium avium subsp. paratuberculosis (MAP) infections in sheep from four governorates in Egypt, using a latent class model (LCM) fitted within a Bayesian framework. Furthermore, the within-governorate prevalence of MAP infection in sheep was estimated as a secondary objective. Fecal and blood samples were collected from 370 sheep in four Egyptian governorates. Fecal samples were analyzed by IFC and RT-PCR based on ISMav2 gene, while ELISA was performed on serum samples. The sensitivity (Se) and specificity (Sp) of the three diagnostic tests were estimated using a three-tests-four-populations Bayesian LCM to obtain posterior estimates [medians and 95% Bayesian credible intervals (95% BCI)] for each parameter. The median Se estimates (95% BCI) for IFC, FPCR, and serum ELISA were 31.8% (22.8–41.4), 49.7% (31.8–79.9), and 61.2% (39.8–81.4), respectively. The median Sp estimates (95% BCI) for IFC, FPCR, and serum ELISA were 97.7% (96.1–98.9), 97.7% (95.6–99.5), and 98.4% (96.9–99.3), respectively. The median within-governorate paratuberculosis prevalence (95% BCI) was 5.2% (1.1–13.6), 8.4% (2.9–17.7), 9.4% (3.0–20.7), and 18.2% (10.5–29.5) for the Gharbia, Menoufia, Qalyubia, and Kafr El-Sheikh governorates, respectively. In conclusion, at a ratio of the optical density (OD) sample/OD positive control threshold of > 45%, ELISA showed the highest Se among the three tests and comparable Sp to IFC and FPCR. The test ELISA evaluated in this study is an interesting alternative for detecting MAP in sheep due to its higher Se, lower cost, and shorter turnaround laboratory time compared to IFC and FPCR.

Research Area(s)

  • Bayesian modelling, Fecal culture, Fecal PCR, Paratuberculosis, Sensitivity, Serum ELISA, Sheep, Specificity

Citation Format(s)

Bayesian estimation of sensitivity and specificity of fecal culture, fecal PCR and serum ELISA for diagnosis of Mycobacterium avium subsp. paratuberculosis infections in sheep. / Elsohaby, Ibrahim; Arango-Sabogal, Juan Carlos; Selim, Abdelfattah; Attia, Kotb A.; Alsubki, Roua A.; Mohamed, Arif M.; Megahed, Ameer.

In: Preventive Veterinary Medicine, Vol. 206, 105712, 09.2022.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review