Management of Irukandji syndrome in northern Australia. (1/30)

INTRODUCTION: Irukandji syndrome, a potentially life-threatening condition that follows the sting of small carybdeid jellyfish, occurs along the northern Australian coastline from Broome, Western Australia in the west to Rockhampton, Queensland in the east. Much of this area is classified rural or remote. Because correct patient management is essential to avoid unnecessary fatality, and stings are relatively uncommon in any specific location, it was considered important to document current approaches to Irukandji syndrome management throughout coastal northern Australia, comparing urban and more rural health facilities, and to assess the availability of management guidelines for health staff. METHODS: A telephone survey of the clinicians responsible for Irukandji syndrome patient management at 34 coastal northern Australian health facilities that might encounter this patient presentation was conducted during November and December 2003. Healthcare providers responsible for Irukandji syndrome management on the day of survey were interviewed using a structured, standardized questionnaire, which included a description of a hypothetical patient with Irukandji syndrome. This was used to stimulate a spontaneous description of the usual response of the particular health facility to such a patient presentation. Additional vignettes were used to investigate further specific aspects of patient management, including first aid, and pain and blood pressure management. Respondents were also asked about the existence of Irukandji treatment guidelines at their facility. RESULTS: All 34 facilities contacted agreed to participate. Five health facilities were in urban centres with a population of 50,000 or greater, four were within 50 km of such centres, 20 were more remote and five facilities were on islands. Basic clinical monitoring (blood pressure, pulse, respiratory rate and oxygen saturation) was generally adequately practised. Topical application of vinegar as a first aid measure was described by 79% of respondents, with spontaneous mention of vinegar significantly associated with increasing remoteness (p = 0.023). Other sting site management was variable, with uncertainty about the use of pressure immobilisation bandaging. Intravenous opiate analgesia was administered at 91% of facilities, and magnesium sulphate, a treatment that is still being evaluated for its role in Irukandji syndrome-related pain and hypertension, was mentioned by 12% of respondents for pain relief. Twelve different pharmacological treatments were used for syndrome-associated hypertension, with magnesium sulphate being mentioned by 21% of respondents. Of the 22 facilities with guidelines, 14 used either the Primary Clinical Care Manual or the Central Australian Rural Practitioners Association Standard Treatment Manual. The remaining guidelines were independently produced protocols. The availability of guidelines was associated with appropriate use of intravenous opiate for adequate pain relief (p = 0.037). Although all urban health centres and 75% of health facilities <50 km away had guidelines, only 56% of more remote or island facilities reported the availability of guidelines. CONCLUSIONS: Although monitoring and pain management of patients with Irukandji syndrome were generally appropriate, a variety of inappropriate first aid and hypertension management approaches were found. In general, appropriate practice was associated with the presence of guidelines but, unfortunately, guidelines were less often present in remote health facilities. This is particularly important because the majority of respondents who reported no experience of managing Irukandji syndrome were located in more remote settings. There is a need for uniform, evidence-based guidelines, and mechanisms for effective dissemination of these guidelines with training for all health staff who may be required to manage Irukandji syndrome, particularly in remote areas of northern Australia.  (+info)

Muscle organization of the cubozoan jellyfish Tripedalia cystophora Conant 1897. (2/30)

The musculature of the cubomedusa Tripedalia cystophora was investigated using immunohistochemical staining with an anti-actin antibody and histochemical staining with fluorescent phalloidin. The subumbrella is lined with a sheet of circular, striated muscle that is interrupted at the perradii, and by the nerve ring. The sheet is continuous with circular, striated muscle of the velarium, which turns radially on each face of the four velarial frenula. Perradial strips of smooth muscle run radially from just above the level of the rhopalia into the manubrium and lips. The strips give off perpendicular offshoots that run a short distance in parallel with the circular swim muscle. Musculature of the tentacles and pedalia is longitudinal and limited to the oral side of the pedalia. The pedalial muscle connects with bundles of smooth muscle that runs circularly from the tentacle base well into the subumbrella. The arrangement of striated muscle in the frenula suggests that these structures may function in directional nozzle formation of the velarium during turning. In addition, the perpendicular branching of the radial strips and the circular extensions of pedalial muscle may function in hinge formation to aid bending of the pedalia and tentacles into the subumbrella during feeding and protective responses.  (+info)

A randomized, controlled field trial for the prevention of jellyfish stings with a topical sting inhibitor. (3/30)

BACKGROUND: Jellyfish stings are a common occurrence among ocean goers worldwide with an estimated 150 million envenomations annually. Fatalities and hospitalizations occur annually, particularly in the Indo-Pacific regions. A new topical jellyfish sting inhibitor based on the mucous coating of the clown fish prevents 85% of jellyfish stings in laboratory settings. The field effectiveness is unknown. The objective is to evaluate the field efficacy of the jellyfish sting inhibitor, Safe Sea. METHODS: A double-blind, randomized, placebo-controlled trial occurred at the Dry Tortugas National Park, FL, USA and Sapodilla Cayes, Belize. Participants were healthy volunteers planning to snorkel for 30 to 45 minutes. Ten minutes prior to swimming, each participant was directly observed applying a blinded sample of Safe Sea (Nidaria Technology Ltd, Jordan Valley, Israel) to one side of their body and a blinded sample of Coppertone (Schering-Plough, Kenilworth, NJ, USA) to the contralateral side as placebo control. Masked 26 g samples of both Safe Sea SPF15 and Coppertone SPF15 were provided in identical containers to achieve 2 mg/cm(2) coverage. Sides were randomly chosen by participants. The incidence of jellyfish stings was the main outcome measure. This was assessed by participant interview and examination as subjects exited the water. RESULTS: A total of 82 observed water exposures occurred. Thirteen jellyfish stings occurred during the study period for a 16% incidence. Eleven jellyfish stings occurred with placebo, two with the sting inhibitor, resulting in a relative risk reduction of 82% (95% confidence interval: 21%-96%; p= 0.02). No seabather's eruption or side effects occurred. CONCLUSIONS: Safe Sea is a topical barrier cream effective at preventing >80% jellyfish stings under real-world conditions.  (+info)

The spectral sensitivity of the lens eyes of a box jellyfish, Tripedalia cystophora (Conant). (4/30)

Box jellyfish, or cubomedusae (class Cubozoa), are unique among the Cnidaria in possessing lens eyes similar in morphology to those of vertebrates and cephalopods. Although these eyes were described over 100 years ago, there has been no work done on their electrophysiological responses to light. We used an electroretinogram (ERG) technique to measure spectral sensitivity of the lens eyes of the Caribbean species Tripedalia cystophora. The cubomedusae have two kinds of lens eyes, the lower and upper lens eyes. We found that both lens eye types have similar spectral sensitivities, which likely result from the presence of a single receptor type containing a single opsin. The peak sensitivity is to blue-green light. Visual pigment template fits indicate a vitamin A-1 based opsin with peak sensitivity near 500 nm for both eye types.  (+info)

Visually guided obstacle avoidance in the box jellyfish Tripedalia cystophora and Chiropsella bronzie. (5/30)

Box jellyfish, cubomedusae, possess an impressive total of 24 eyes of four morphologically different types. Two of these eye types, called the upper and lower lens eyes, are camera-type eyes with spherical fish-like lenses. Compared with other cnidarians, cubomedusae also have an elaborate behavioral repertoire, which seems to be predominantly visually guided. Still, positive phototaxis is the only behavior described so far that is likely to be correlated with the eyes. We have explored the obstacle avoidance response of the Caribbean species Tripedalia cystophora and the Australian species Chiropsella bronzie in a flow chamber. Our results show that obstacle avoidance is visually guided. Avoidance behavior is triggered when the obstacle takes up a certain angle in the visual field. The results do not allow conclusions on whether color vision is involved but the strength of the response had a tendency to follow the intensity contrast between the obstacle and the surroundings (chamber walls). In the flow chamber Tripedalia cystophora displayed a stronger obstacle avoidance response than Chiropsella bronzie since they had less contact with the obstacles. This seems to follow differences in their habitats.  (+info)

Unique structure and optics of the lesser eyes of the box jellyfish Tripedalia cystophora. (6/30)

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Assembly of the cnidarian camera-type eye from vertebrate-like components. (7/30)

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Preliminary observations on the response of Chironex fleckeri (Cnidaria: Cubozoa: Chirodropida) to different colors of light. (8/30)

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 world's 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.  (+info)

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