Rapid and Accurate Species-Specific PCR for the Identification of Lethal Chironex Box Jellyfish in Thailand

Abstract

Box jellyfish are extremely potent venom-producing marine organisms. While they have been found worldwide, the highest health burden has been anticipated to be the tropical Indo-Pacific of Southeast Asia (SEA). At least 12 Cubozoan species have now been documented in Thai waters, and many of them inflict acutely lethal strings, especially those under the order Chirodropida. Our previous study has successfully differentiated species of box jellyfish using DNA sequencing to support the morphological study. In this study, we specifically designed polymerase chain reaction (PCR) primers for the 16S ribosomal RNA (rRNA) gene and the mitochondrial DNA cytochrome oxidase subunit I (COI) gene of lethal Thai Chironex species. The SYBR green-based real-time PCR panel was performed for rapid species identification. The sensitivity and specificity of the panel were determined by testing samples of different species. Moreover, we applied the panel to the tentacle sample from a real patient, which helped confirm the animal-of-cause of envenomation. Our results show a success for species identification of box jellyfish using 16S rRNA and COI PCR panel, which revealed congruence between molecular and morphological identification. Furthermore, the panel worked very well with the unknown samples and jellyfish tissue from the real envenomation case. The results demonstrated that molecular panels were able to identify three species of Chironex box jellyfish both rapidly and accurately, and can be performed without having a complete specimen or morphological study.

Population Structures and Levels of Connectivity for Scyphozoan and Cubozoan Jellyfish

“…Although Chironex indrasaksajiae and an unnamed species from Western Australia appear to have very restricted distributions, this may in part be due to their recent discovery and description. Further, a study using PCR primers has detected another two incipient species in the waters of Thailand [24].…”

“…Further, genetic sequencing used to develop species-specific PCR primers for Chironex indrasaksajiae revealed two incipient species in Thailand (Figure 1). Although there is a strong suggestion that these taxa may have small metapopulations, each species has only been detected at one or two sites [24]. This review highlights the need for population genetic studies to be undertaken on cubozoan taxa, as this would develop a more in-depth understanding of the ecology of these cryptic and elusive taxa, thereby assisting in the management of these potentially deadly organisms [11].…”

“…Separate metapopulations, or in some cases more than one, likely correspond to Large Marine Ecosystems (LME) coined by Abboud et al [20]. Chironex yamaguchii [21]; Chironex indrasaksajiae [22], and unnamed species in northern Austra [23] and Thailand [24]; Taxonomy [25]).…”

“…Accordingly, successful immigration emigration, involving any life history stage, should be very low or zero [27]. It is pos that an incipient stock is largely separate ecologically, but there is sufficient geneti Chironex yamaguchii [21]; Chironex indrasaksajiae [22], and unnamed species in northern Australia [23] and Thailand [24]; Taxonomy [25]).…”

“…The geographic range of all know species of Chironex. Chironex fleckeri Southcott, 1956;Chironex yamaguchii[21]; Chironex indrasaksajiae[22], and unnamed species in northern Australia[23] and Thailand[24]; Taxonomy[25]).…”