Lisa-Ann Gershwin

CARDIOVASCULAR ACTIONS OF THE VENOM FROM THE IRUKANDJI ( CARUKIA BARNESI ) JELLYFISH: EFFECTS IN HUMAN, RAT AND GUINEA-PIG TISSUES IN VITRO AND IN PIGS IN VIVO

1. We have investigated the cardiovascular pharmacology of the crude venom extract (CVE) from the potentially lethal, very small carybdeid jellyfish Carukia barnesi, in rat, guinea‐pig and human isolated tissues and anaesthetized piglets.

Marine Stingers: Review of an Under-Recognized Global Coastal Management Issue

Dangerous marine stingers (jellyfish) are an emotive issue in tropical Australia, where they are widely regarded as the number one marine health threat. However, numerous severe and fatal stings have been reported throughout the tropical and temperate seas of the world, indicating that marine stingers are a global health problem. Further, life-threatening jellyfish stings are more frequently reported globally now compared to earlier decades, possibly as a result of improved recognition and reporting, or increased spatial and/or temporal distribution or densities. As stinging incidents may also have significant financial implications (lost tourism revenues and liability settlements), and the treatment of envenomed patients comes at high cost to the taxpayer, this issue is also a management challenge. This article outlines suggested approaches, based largely on Australian experience, for dealing with this under-recognized global coastal management issue.

Fatal and severe box jellyfish stings, including Irukandji Stings, in Malaysia, 2000-2010.

BACKGROUND Jellyfish are a common cause of injury throughout the world, with fatalities and severe systemic events not uncommon after tropical stings. The internet is a recent innovation to gain information on real-time health issues of travel destinations, including Southeast Asia. METHODS We applied the model of internet-based retrospective health data aggregation, through the Divers Alert Network Asia-Pacific (DAN AP), together with more conventional methods of literature and media searches, to document the health significance, and clinical spectrum, of box jellyfish stings in Malaysia for the period January 1, 2000 to July 30, 2010. RESULTS Three fatalities, consistent with chirodropid envenomation, were identified for the period-all tourists to Malaysia. Non-fatal chirodropid stings were also documented. During 2010, seven cases consistent with moderately severe Irukandji syndrome were reported to DAN and two representative cases are discussed here. Photographs of chirodropid (multi-tentacled), carybdeid (four-tentacled) box jellyfish, and of severe sting lesions were also submitted to DAN during this period. CONCLUSIONS This study suggests that the frequency and severity of jellyfish stings affecting tourists in Southeast Asia have been significantly underestimated. Severe and fatal cases of chirodropid-type stings occur in coastal waters off Peninsular Malaysia and Sabah, Borneo. Indeed, the first Malaysian cases consistent with Irukandji-like syndrome are reported here. Reports to DAN, a provider of emergency advice to divers, offer one method to address the historic lack of formalized reporting mechanisms for such events, for photo-documentation of the possible culprit species and treatment advice. The application of marine stinger prevention and treatment principles throughout the region may help reduce the incidence and severity of such stings. Meanwhile travelers and their medical advisors should be aware of the hazards of these stings throughout the Asia-Pacific.

Biology and ecology of Irukandji jellyfish (Cnidaria: Cubozoa)

Irukandji stings are a leading occupational health and safety issue for marine industries in tropical Australia and an emerging problem elsewhere in the Indo-Pacific and Caribbean. Their mild initial sting frequently results in debilitating illness, involving signs of sympathetic excess including excruciating pain, sweating, nausea and vomiting, hypertension and a feeling of impending doom; some cases also experience acute heart failure and pulmonary oedema. These jellyfish are typically small and nearly invisible, and their infestations are generally mysterious, making them scary to the general public, irresistible to the media, and disastrous for tourism. Research into these fascinating species has been largely driven by the medical profession and focused on treatment. Biological and ecological information is surprisingly sparse, and is scattered through grey literature or buried in dispersed publications, hampering understanding. Given that long-term climate forecasts tend toward conditions favourable to jellyfish ecology, that long-term legal forecasts tend toward increasing duty-of-care obligations, and that bioprospecting opportunities exist in the powerful Irukandji toxins, there is a clear need for information to help inform global research and robust management solutions. We synthesise and contextualise available information on Irukandji taxonomy, phylogeny, reproduction, vision, behaviour, feeding, distribution, seasonality, toxins, and safety. Despite Australia dominating the research in this area, there are probably well over 25 species worldwide that cause the syndrome and it is an understudied problem in the developing world. Major gaps in knowledge are identified for future research: our lack of clarity on the socio-economic impacts, and our need for time series and spatial surveys of the species, make this field particularly enticing.

Comparison of Eight Types of Protective Clothing against Irukandji Jellyfish Stings

Abstract Marine stingers hospitalize approximately 100 people annually in tropical Australian waters, and are known to have caused at least 73 fatalities. Elsewhere in the tropical and temperate seas of the world, marine stingers pose a similar threat to human safety, and reported sting numbers are on the rise. Lycra body suits (“stinger suits”) have been used for stinger protection since the early 1980s, but have not been formally tested as a barrier against Irukandji (Carukia barnesi) tentacles. Other products are being used and developed; however, no safety standards currently exist for this widely used form of protective equipment. Eight products were tested with live C. barnesi: a Lycra stinger suit used by Surf Life Saving, a product developed by ROBIS Pty. Ltd. and marketed as “The Stinger Suit”, three different styles of nylon pantyhose, two sport products designed to “wick away” moisture and keep the wearer cooler, and a 0.5-mm neoprene wetsuit. Products were evaluated for seven common concerns relating to safety and practical wearability. Primary concerns, i.e., those relating to performance of the fabric in preventing stings, include: ease of penetration by jellyfish tentacles, adherence of tentacles or body to fabric, and potential for crushing through the fabric. Secondary concerns, i.e., those relating to overall usage as stinger-preventative clothing, include: durability or integrity of the barrier, whether the product is available as a one-piece garment, heat-retention properties, and product cost. In general, the tighter the fabric weave, the better tentacle exclusion, and the smoother the fabric, the more resistant to adherence. Lycra is vulnerable to crushing of tentacles through the fabric, but appears to be the best choice for routine-use stinger-protective clothing. Recommendations are made for safe use of protective clothing, as a basis for development of an Australian Standard in protective clothing for marine stinger safety.

The pharmacology of Malo maxima jellyfish venom extract in isolated cardiovascular tissues: A probable cause of the Irukandji syndrome in Western Australia

The in vitro cardiac and vascular pharmacology of Malo maxima, a newly described jellyfish suspected of causing Irukandji syndrome in the Broome region of Western Australia, was investigated in rat tissues. In left atria, M. maxima crude venom extract (CVE; 1-100μg/mL) caused concentration-dependent inotropic responses which were unaffected by atropine (1μM), but significantly attenuated by tetrodotoxin (TTX; 0.1μM), propranolol (1μM), Mg(2+) (6mM) or calcitonin gene-related peptide antagonist (CGRP(8-37); 1μM). CVE caused no change in right atrial rate until 100μg/mL, which elicited bradycardia. This was unaffected by atropine, TTX, propranolol or CGRP(8-37). In the presence of Mg(2+), CVE 30-100μg/mL caused tachycardia. In small mesenteric arteries CVE caused concentration-dependent contractions (pEC(50) 1.03±0.07μg/mL) that were unaffected by prazosin (0.3μM), ω-conotoxin GVIA (0.1μM) or Mg(2+) (6mM). There was a 2-fold increase in sensitivity in the presence of CGRP(8-37) (3μM). TTX (0.1μM), box jellyfish Chironex fleckeri antivenom (92.6U/mL) and benextramine (3μM) decreased sensitivity by 2.6, 1.9 and 2.1-fold, respectively. CVE-induced maximum contractions were attenuated by C. fleckeri antivenom (-22%) or benextramine (-49%). M. maxima CVE appears to activate the sympathetic, but not parasympathetic, nervous system and to stimulate sensory nerve CGRP release in left atria and resistance arteries. These effects are consistent with the catecholamine excess thought to cause Irukandji syndrome, with additional actions of CGRP release.

Preliminary Observations on the Response of Chironex fleckeri (Cnidaria: Cubozoa: Chirodropida) to Different Colors of Light

Cubozoans are well known for their attraction to light and light-colored objects. Two highly venomous types are a public safety concern in Australian waters and elsewhere: Chironex fleckeri, long considered the worlds deadliest animal and colloquially called the box jellyfish; and the irukandjis, a group of at least 10 species that cause various degrees of debilitating illness. We were asked by the tourism industry whether there might be a color of light that box jellyfish and irukandjis are not attracted to, such that nighttime diving activities might pose less risk of being stung. Our preliminary trials with Chironex fleckeri indicated a marked positive response to lights of white, red, yellow, green, orange, and blue. All colors elicited a strong and directed attraction to light; however, medusae slowed down their pulsation rate, streamed out their tentacles, and performed a series of figure-eight patterns back and forth through the lighted area when exposed to blue light, which we interpreted as feeding behavior. This compares curiously with a report subsequent to our testing, in which the small, mangrove-inhabiting cubomedusa Tripedalia cystophora and the beach-dwelling Chiropsella bronzie demonstrate a peak sensitivity to blue-green light in the region of 500 nm, and that the former is behaviorally attracted to blue and green light, but ignores red. This leaves open the possibility that Irukandji species, which are more closely related to Tripedalia than to Chironex, may be blind to red.

Chrysaora achlyos, a Remarkable New Species of Scyphozoan from the Eastern Pacific

An enormous new species of scyphozoan jellyfish, Chrysaora achlyos, is described from the eastern Pacific. The description is based primarily on color photographs and video footage of living animals and the morphology of four specimens collected in 1989. The natural history, life cycle, and sporadic appearance of the species all are unknown. The species appeared most recently in large numbers in 1989 but has appeared at least twice previously in this century; published photographs (unlabeled or incorrectly identified) appeared in 1926 and 1965. The species is easily distinguished by its size and coloration from other known species in the genus, all of which are considerably smaller. Morphological characters are described, and limited data on nematocyst types are presented. Because of the size of the new species and the known potency of the sting of congeners, we mention briefly the possible consequences of human contact.