Rapid and Simple Detection Method of “Candidatus Xenohaliotis californiensis” Using Fecal PCR in Abalone Haliotis discus discus and H. gigantea

抄録

We developed a simple PCR-based method using feces to detect “Candidatus Xenohaliotis californiensis” (Rickettsia-like organism, RLO), which is responsible for withering syndrome (WS). Four abalone groups (Haliotis discus discus and H. gigantea) naturally or artificially infected with WS-RLO were prepared. After daily collection of the feces from individual animals over a seven-day period, the posterior esophagus (PE) was excised, and subjected to PCR for WS-RLO. WS-RLO-positive results were obtained from the feces of 30-67% animals, and from the PE of 17-97% animals. For the fecal PCR, more than one animal was positive from each group every day, although the WS-RLO-positive rate daily varied. When the sensitivity of the PCR was compared between DNA extracted from feces by boiling and that by QIAamp^® DNA Stool Kit, there was no difference between the two methods. Fecal PCR combined with boiling DNA extraction is rapid and simple for screening abalone groups infected with WS-RLO.