Diagnostic performance of different fecal Lawsonia intracellularis-specific polymerase chain reaction assays as diagnostic tests for proliferative enteropathy in pigs: a review.
Traditionally, diagnosis of Lawsonia intracellularis-associated proliferative enteropathy (PE) has depended on necropsy and histology. Since the establishment of the etiologic role of L. intracellularis, a number of specific polymerase chain reaction (PCR) assays have been developed for the detection of DNA in feces. The present article is a systematic review of peer-reviewed publications on the application of L. intracellularis-specific fecal PCR as an antemortem diagnostic test for histologic lesions of PE in pigs. Based on this information, a range of diagnostic sensitivities (36-100%) and specificities (50-100%) of the published tests was calculated. Validity and confidence limits of the estimates varied considerably. The positive and negative predictive values of 6 different PCR assays were calculated for PE prevalence of 15%, 30%, 45%, 60%, 75%, and 90%, using a histologic case definition of PE and based on the reported test sensitivities and specificities. The simulated predictive values suggested that applying the fecal PCR assay as a diagnostic test is more likely to overestimate than underestimate the number of pigs having histologic lesions of PE under field conditions.
Pedersen
Ken Steen
KS
Department of Large Animal Sciences, University of Copenhagen, Groennegaardsvej 2, DK-1870 Frederiksberg C, Denmark. ken@life.ku.dk
Holyoake
Patricia
P
Stege
Helle
H
Nielsen
Jens Peter
JP
D000818:Animals; D045824:Desulfovibrionaceae Infections / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D007410:Intestinal Diseases / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D020639:Lawsonia Bacteria; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000175:diagnosis* / Q000382:microbiology