title: Investigation of false positives associated with loop-mediated isothermal amplification assays for detection of Toxoplasma gondii in archived tissue samples of captive felids.
abstract: Toxoplasma gondii is a ubiquitous protozoan parasite that infects humans and many different animals, including felids. Many molecular and serologic tests have been developed for detection of T. gondii in a wide range of hosts. Loop-mediated isothermal amplification (LAMP) is a field-friendly technique that lacks the practical drawbacks of other molecular and serologic tests, and LAMP assays have been successfully developed for detection of T. gondii in fresh tissue samples. In the current study, both a previously published and a de-novo designed LAMP assay were compared to a quantitative real-time (q)PCR assay, for the detection of T. gondii in archived formalin-fixed, paraffin-embedded (FFPE) tissue samples from captive wildlife. The LAMP assays produced conflicting results, generating both false positives and false negatives. Furthermore, the LAMP assays were unable to positively identify samples with low levels of parasites as determined by qPCR and histopathology. Therefore, these LAMP assays may not be the most suitable assays for detection of T. gondii in archived FFPE and frozen tissue samples.
authors.affiliation: National Zoological Gardens of South Africa, Research and Scientific Services Department, Pretoria, South Africa (Suleman, Mtshali, Lane)University of Witwatersrand, Strategic Planning Division, Wits, South Africa (Mtshali)University of the Free State, Department of Zoology and Entomology, Phuthaditjhaba, South Africa (Mtshali) essa@nzg.ac.za.
authors.forename: Essa
authors.initials: E
authors.lastname: Suleman
authors.affiliation: National Zoological Gardens of South Africa, Research and Scientific Services Department, Pretoria, South Africa (Suleman, Mtshali, Lane)University of Witwatersrand, Strategic Planning Division, Wits, South Africa (Mtshali)University of the Free State, Department of Zoology and Entomology, Phuthaditjhaba, South Africa (Mtshali).
authors.forename: Moses Sibusiso
authors.initials: MS
authors.lastname: Mtshali
authors.affiliation: National Zoological Gardens of South Africa, Research and Scientific Services Department, Pretoria, South Africa (Suleman, Mtshali, Lane)University of Witwatersrand, Strategic Planning Division, Wits, South Africa (Mtshali)University of the Free State, Department of Zoology and Entomology, Phuthaditjhaba, South Africa (Mtshali).
authors.forename: Emily
authors.initials: E
authors.lastname: Lane
mesh_terms: D000818:Animals; D000835:Animals, Wild; D002371:Cat Diseases / Q000175:diagnosis* / Q000469:parasitology; D002415:Cats; D016054:DNA, Protozoan / Q000032:analysis; D005189:False Positive Reactions; D021141:Nucleic Acid Amplification Techniques / Q000662:veterinary; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D014122:Toxoplasma / Q000235:genetics / Q000302:isolation & purification*; D014123:Toxoplasmosis / Q000175:diagnosis* / Q000469:parasitology
chemical_list: D016054:DNA, Protozoan
keywords: Felids; Toxoplasma gondii; formalin-fixed; loop-mediated isothermal amplification