Parafilaroides decorus

Williams, Kalani M., Fessler, M. K., Bloomfield, R. A., Sandke, William D., Malekshahi, Clara R., Keroack, Caroline D., Duignan, Pádraig J., Torquato, Samantha D. & Williams, Steven A., 2020, A novel quantitative real-time PCR diagnostic assay for fecal and nasal swab detection of an otariid lungworm, Parafilaroides decorus, International Journal for Parasitology: Parasites and Wildlife 12, pp. 85-92 : 90-91

4.3. Detection of P. decorus in fecal samples

Using the Pd65 qPCR assay, P. decorus was detected in fecal samples from all animals with known P. decorus infections. Furthermore, all of the estimates of the amount of P. decorus DNA found in the fecal samples were less than the total 1 ng of DNA in the fecal sample (at a maximum of 48% of the total DNA), which suggests that the P. decorus

DNA estimates are likely correct, since most of the DNA in a fecal sample should be host and bacterial DNA. Unfortunately, we cannot directly estimate the concentration of larvae in the feces because the correlation between egg DNA concentration in the feces and number of larvae is currently unknown for P. decorus .

Host CSL-13534, notably, was not known to have a P. decorus infection based on the fecal testing and necropsy data ( Tables 1 and 4). Infections with these particularly small nematodes can be easily missed in necropsies and, more importantly, in fecal Baermann tests that can be processed while the animal is still alive. This demonstrates that the Pd65 assay can detect infections that would otherwise be missed. This scenario is similar to soil transmitted helminth molecular diagnostic assays, which are often able to detect infections that are missed by visual fecal examination methods due to storage methods causing eggs to break down or human error ( Pilotte et al., 2016, 2019; Easton et al., 2017).