Environmental drivers of the occurrence and abundance of the Irukandji jellyfish (Carukia barnesi).

Understanding the links between species and their environment is critical for species management. This is particularly true for organisms of medical and/or economic significance. The 'Irukandji' jellyfish (Carukia barnesi) is well known for its small size, cryptic nature, and highly venomous sting. Being the namesake of the Irukandji syndrome, contact with this marine stinger often leads to hospitalization and can be fatal. Consequently, the annual occurrence of this organism is believed to cost the Australian government an estimated $AUD3 billion annually in medical costs and losses for tourism. Despite its economic importance the logistical difficulties related to surveying C.barnesi in situ has led to a paucity of knowledge regarding its ecology and significantly impeded management strategies to date. In this study, we use six years of direct C. barnesi capture data to explore patterns pertaining to the annual occurrence and abundance of this species in the nearshore waters of the Cairns coast. We provide novel insights into trends in medusae aggregations and size distribution and primarily focus on the potential role of environmental drivers for annual C. barnesi occurrence patterns. Using a two-part hurdle model, eight environmental parameters were investigated over four time periods for associations with records of medusa presence and abundance. Final models showed a small amount of variation in medusa presence and abundance patterns could be accounted for by long-term trends pertaining to rainfall and wind direction. However, the assessed environmental parameters could not explain high annual variation or site location effects. Ultimately best-fit models had very low statistical inference power explaining between 16 and 20% of the variance in the data, leaving approximately 80% of all variation in medusa presence and abundance unexplained.

Use of clonidine in the treatment of Irukandji syndrome: A 4-year retrospective cohort study on safety, efficacy and clinical utility.

OBJECTIVE: Irukandji syndrome (IS) is an extremely painful condition that causes a significant catecholamine surge and sympathetic autonomic response related to the envenomation from certain types of jellyfish. Current management involves intravenous fluids, magnesium sulphate and large doses of opioids for symptom control. Clonidine, a centrally acting alpha-2 agonist, is often used as an analgesic adjunct to reduce opioid requirements in acute pain. The present study explores the safety and efficacy of clonidine in reducing opioid requirements in IS. METHODS: All patients diagnosed with IS at Cairns Hospital between 1 March 2016 and 30 April 2020, and participants from the Magnesium in Irukandji Study Trial, were included in this retrospective study (n = 114). Cases were separated into two groups depending on whether or not they received clonidine, and subsequently analysed according to pre- and post-intervention opioid requirements, clonidine dose administered and adverse effects. RESULTS: Notably, 39 patients with IS received ≥1 mcg/kg clonidine and the remaining 75 did not. There was no difference in oral morphine equivalent daily dose (oMEDD) between groups before clonidine administration; however, there was a significant reduction in oMEDD required after patients received clonidine (26.1 mg; 95% CI 4.6-47.7) compared with those who did not (66.6 mg; 95% CI 56.9-86.1) (F = 8.722, df = 1 × 224, P = 0.003). One episode of hypotension occurred following the intervention. CONCLUSION: Patients with IS who received clonidine required significantly lower opioid requirements than those who did not receive clonidine. Clonidine was safe to administer and should be considered early when treating IS. The optimal clonidine dose remains unclear and requires prospective studies to validate our findings.

Complex patterns of circulating fatty acid levels in gestational diabetes mellitus subclasses across pregnancy.

BACKGROUND & AIMS: To investigate the relationship between maternal serum fatty acid levels and gestational diabetes mellitus (GDM) subtypes across pregnancy. METHODS: A total of 680 singleton mothers enrolled in the Complex Lipids in Mothers and Babies (CLIMB) study in Chongqing, China were included. Clinical information and serum samples were collected at gestational weeks (GWs) 11-14, 22-28, and 32-34. 75 g Oral Glucose Tolerance Test (OGTT) was conducted at GW 24-28 and GDM subtypes divided into three groups using International Association of Diabetes and Pregnancy Study Group (IADPSG) guidelines criteria: elevated fasting plasma glucose (FPG group; n = 59); 1-h and/or 2-h post-load glucose (1h/2h-PG group; n = 94); combined group (FPG&1h/2h-PG group; n = 42). Non-GDM pregnancies were included (n = 485) as controls. Twenty fatty acids were quantified in serum using gas chromatography-mass spectrometry (GC-MS) analysis. RESULTS: Overall, most serum fatty acid concentrations increased rapidly from the first to second trimester, followed by a plateauing or reduction in the third trimester (p < 0.001). In cross sectional analysis, fatty acid concentrations were significantly higher in the FPG group at GW 11-14 and decreased in the 1h/2h-PG group at GW 32-34, relative to controls. Moreover, higher α-linolenic acid (ALA; the second tertile: adjusted odds ratio [aOR] = 2.53, 95% CI: 1.17 to 5.47; the third tertile: aOR = 2.60, 95% CI: 1.20 to 5.65) and docosahexaenoic acid (DHA; the second tertile: aOR = 2.34, 95% CI: 1.10 to 4.97; the third tertile: aOR = 2.16, 95% CI: 1.00 to 4.63) were significantly associated with a higher risk of GDM in women with elevated fasting plasma glucose at GW 11-14 (first tertile as reference). CONCLUSIONS: Our findings highlight the importance of considering GDM subtypes for the individualised management of GDM in pregnancy. ALA and DHA in early pregnancy are associated with a higher risk of FPG-GDM subtype. This has widespread implications when recommending n-3 PUFAs supplementation for women with GDM.

An analysis of omega-3 fatty acid status in a population of pregnant women with obesity, at higher risk of preterm birth.

An updated Cochrane Review showed that maternal supplementation with omega-3 fatty acids reduced preterm birth, offering a potential strategy for prevention. We hypothesised that pregnant women with obesity, at higher risk of preterm birth, would have low omega-3 fatty acid levels and may benefit from supplementation. Our study measured the omega-3 fatty acid levels of 142 participants from the Healthy Mums and Babies study, Counties Manukau, Auckland, New Zealand. Counties Manukau is a multi-ethnic community with high rates of socio-economic deprivation, obesity, and preterm birth. Red blood cell omega-3 fatty acid levels were measured from samples collected between 120 and 176 weeks' gestation. Contrary to our hypothesis, participants in our study had similar or higher levels of omega-3 fatty acids to those reported in pregnant populations in Australia, Norway, China, and Germany. Our findings emphasise the importance of testing omega-3 fatty acid status before supplementing groups at risk of preterm birth.

Omega-3 fatty acids to prevent preterm birth: Australian pregnant women's preterm birth awareness and intentions to increase omega-3 fatty acid intake.

BACKGROUND: Preterm birth is the leading cause of death in children under five. A recent Cochrane review found a 42% reduction in early preterm birth (< 34 weeks' gestation) and 11% reduction in preterm birth (< 37 weeks' gestation) with omega-3 fatty acid supplementation. To assist in the development of implementation strategies to increase pregnant women's omega-3 fatty acid intake, we assessed the awareness of Australian pregnant women about preterm birth, their nutrition and supplementation behaviours during pregnancy, and intentions to increase omega-3 fatty acid intake. METHODS: A ten-minute survey was conducted online to assess the knowledge, attitudes, behaviours, and intentions of Australian pregnant women across three domains: (1) preterm birth; (2) nutrition and supplementation during pregnancy; and (3) omega-3 fatty acid consumption to prevent preterm birth. Participants were recruited from Survey Sampling International's research panels. RESULTS: Of the 763 women who completed the survey, less than two-thirds had heard of preterm birth. Over 55% of respondents had changed their diet during pregnancy and a prenatal dietary supplement was consumed by 82% of the women surveyed. Respondents' main source of information about preterm birth and nutrition during pregnancy was from a health professional. When asked about their intentions to increase their omega-3 fatty acid intake following a health professional's recommendation, the vast majority of participants indicated they would increase their omega-3 fatty acid intake (90%). When a hypothetical scenario was presented of an omega-3 fatty acid supplement being offered from a health service at no cost, the number of respondents who selected they would increase their intake through supplementation increased from 54 to 79%. CONCLUSIONS: The main information source for women about preterm birth and dietary supplementation recommendations during pregnancy is their health professional. Therefore, informing women about ways to prevent preterm birth, including the role of omega-3 fatty acids, should occur during antenatal visits. The results from our study are useful for clinicians caring for pregnant women and for the next stage of translation of the Cochrane review findings - the design of implementation strategies to increase the intake of omega-3 fatty acids during pregnancy where needed.

The Impact of Nutritional Interventions in Pregnant Women on DNA Methylation Patterns of the Offspring: A Systematic Review.

Epidemiological studies have consistently demonstrated that environmental exposures in early life are associated with later-life health status and disease susceptibility. Epigenetic modifications, such as DNA methylation, have been suggested as potential mechanisms linking the intrauterine environment with offspring health status. The present systematic review compiles peer-reviewed randomized controlled trials assessing the impact of maternal nutritional interventions on DNA methylation patterns of the offspring. The results of the included trials are consistent with micronutrient supplementation not significantly affecting offspring tissue DNA methylation patterns, yet subgrouping by sex, BMI, and smoking status increased the significance of nutritional supplementation on DNA methylation. Maternal BMI and smoking status as well as offspring sex were factors influencing offspring DNA methylation responsiveness to nutritional interventions during pregnancy. Future research should aim at assessing the impact of nutritional interventions on DNA methylation patterns of neonates comparing single versus multi-micronutrient supplementation, within populations having high versus low baseline nutritional statuses.

Exploring the therapeutic potential of jellyfish venom.

The venom of certain jellyfish has long been known to be potentially fatal to humans, but it is only recently that details of the proteomes of these fascinating creatures are emerging. The molecular contents of the nematocysts from several jellyfish species have now been analyzed using proteomic MS approaches and include the analysis of Chironex fleckeri, one of the most venomous jellyfish known. These studies suggest that some species contain toxins related to peptides and proteins found in other venomous creatures. The detailed characterization of jellyfish venom is likely to provide insight into the diversification of toxins and might be a valuable resource in drug design.

Long-term analysis of Irukandji stings in Far North Queensland.

INTRODUCTION: We reviewed the occurrence, trends, definition and severity of the Irukandji syndrome for the Cairns region of North Queensland, Australia. METHODS: A retrospective analysis of patient files from two sources was conducted: historic accounts kept by Dr Jack Barnes for the period 1942 to 1967, and records from the Emergency Unit in Cairns Base Hospital for 1995 to 2007. RESULTS: There has been a significant increase in the length of the Irukandji season since it was first reliably recorded (15 days in 1961; 151 days in 2002); however, annual numbers of envenomations were highly variable. Traditionally, greater frequencies of Irukandji stings were reported at onshore as opposed to offshore locations. However, in recent years this trend has reversed, potentially because of increased safety protocols for beach regions. Mean Troponin I levels were higher in offshore reef envenomations compared to those from islands or coastal regions. In terms of morphine-equivalent doses, patients given fentanyl received significantly greater opioid doses compared to those given morphine or pethidine. Opioid dosage was indicative of syndrome severity and correlated with other physiological parameters measured. Five major symptoms were associated with Irukandji syndrome: pain, nausea/vomiting, diaphoresis, headache and shortness of breath. Pain was the overwhelming symptom, followed closely by nausea/vomiting. CONCLUSIONS: The duration of the Irukandji season appears to be increasing. Conversely the number of envenomings appears to be decreasing, possibly because of improved beach management in recent years. Offshore envenomings appear to have a higher potential for more severe envenomings with five associated major symptoms.

Irukandji syndrome: a widely misunderstood and poorly researched tropical marine envenoming.

Irukandji syndrome is a poorly defined set of symptoms that occur after envenoming by certain species of jellyfish, primarily cubozoans or 'box jellyfish'. Envenomed victims can show symptoms ranging from headaches, severe pain, nausea and vomiting to pulmonary oedema, cardiac failure and severe hypertension resulting in death. Historically, this syndrome appears to have been misdiagnosed and reported cases are undoubtedly a significant underestimation of the prevalence of this syndrome. The variation in symptoms has resulted in a myriad of treatments though none has been established as definitive. Effective pain relief with opioids is the most immediate priority. Although the annual numbers of envenomations are generally low, the associated financial costs of this envenomation may be comparatively high, with suggestions that it could run to millions of dollars per season in northern Australia alone. The syndrome has been well documented from many areas along the east coast of northern Australia, leading to the belief that it is an Australian oddity. However, with an increase in medical knowledge and improved diagnosis of the condition, it appears that envenomations causing Irukandji syndrome are an increasing marine problem worldwide.

An examination of the cardiovascular effects of an 'Irukandji' jellyfish, Alatina nr mordens.

Irukandji syndrome is usually characterized by delayed severe abdominal, back and chest pain associated with autonomic effects including diaphoresis, hypertension and, in severe cases, myocardial injury and pulmonary oedema. It is most often associated with envenoming by the jellyfish Carukia barnesi, but a number of other jellyfish, including Alatina mordens, are now known to produce Irukandji syndrome. In the present study, nematocyst-derived venom from A. nr mordens (150-250 microg/kg, i.v.) produced a long-lasting pressor effect in anaesthetised rats. This pressor response (250 microg/kg, i.v.) was significantly inhibited by prior administration of the alpha-adrenoceptor antagonist prazosin (200 microg/kg, i.v.) but not by CSL box jellyfish antivenom (300 U/kg, i.v.). A. nr mordens venom 250 microg/kg (i.v.) caused marked increases in plasma adrenaline and noradrenaline concentrations following administration in anaesthetised rats. The venom did not contain appreciable amounts of either adrenaline or noradrenaline. A. nr mordens venom (25 microg/ml) produced a contractile response in rat electrically stimulated vas deferens which was markedly reduced in tissues pre-treated with reserpine (0.1mM) or guanethidine (0.1mM). Sodium dodecyl sulphate (SDS)-PAGE analysis showed that A. nr mordens venom is comprised of multiple protein bands ranging from 10 to 200 kDa. Western blot analysis using CSL box jellyfish antivenom indicated several antigenic proteins in A. nr mordens venom, however, it did not detect all proteins present in the venom. This study characterizes the in vitro and in vivo effects of A. nr mordens venom and indicates that the cardiovascular effects are at least partially mediated by endogenous catecholamine release.

A randomised controlled trial of hot water (45 degrees C) immersion versus ice packs for pain relief in bluebottle stings.

OBJECTIVE: To investigate the effectiveness of hot water immersion for the treatment of Physalia sp. (bluebottle or Portuguese Man-of-War) stings. DESIGN: Open-label, randomised comparison trial. Primary analysis was by intention to treat, with secondary analysis of nematocyst-confirmed stings. One halfway interim analysis was planned. SETTING: Surf lifesaving first aid facilities at two beaches in eastern Australia from 30 December 2003 to 5 March 2005. PARTICIPANTS: 96 subjects presenting after swimming in the ocean for treatment of an apparent sting by a bluebottle. INTERVENTIONS: Hot water immersion (45 degrees C) of the affected part versus ice pack application. MAIN OUTCOME MEASURES: The primary outcome was a clinically important reduction in pain as measured by the visual analogue scale (VAS). Secondary outcomes were the development of regional or radiating pain, frequency of systemic symptoms, and proportion with pruritus or rash on follow-up. RESULTS: 49 patients received hot water immersion and 47 received ice packs. The two groups had similar baseline features, except patients treated with hot water had more severe initial pain (VAS [mean +/- SD]: 54 +/- 22 mm versus 42 +/- 22 mm). After 10 minutes, 53% of the hot water group reported less pain versus 32% treated with ice (21%; 95% CI, 1%-39%; P = 0.039). After 20 minutes, 87% of the hot water group reported less pain versus 33% treated with ice (54%; 95% CI, 35%-69%; P = 0.002). The trial was stopped after the halfway interim analysis because hot water immersion was shown to be effective (P = 0.002). Hot water was more effective at 20 minutes in nematocyst-confirmed stings (95% versus 29%; P = 0.002). Radiating pain occurred less with hot water (10% versus 30%; P = 0.039). Systemic effects were uncommon in both groups. CONCLUSIONS: Immersion in water at 45 degrees C for 20 minutes is an effective and practical treatment for pain from bluebottle stings.

A simple visual system without neurons in jellyfish larvae.

Earlier detailed studies of cnidarian planula larvae have revealed a simple nervous system but no eyes or identifiable light sensing structures. Here, we describe the planula of a box jellyfish, Tripedalia cystophora, and report that these larvae have an extremely simple organization with no nervous system at all. Their only advanced feature is the presence of 10-15 pigment-cup ocelli, evenly spaced across the posterior half of the larval ectoderm. The ocelli are single cell structures containing a cup of screening pigment filled with presumably photosensory microvilli. These rhabdomeric photoreceptors have no neural connections to any other cells, but each has a well-developed motor-cilium, appearing to be the only means by which light can control the behaviour of the larva. The ocelli are thus self-contained sensory-motor entities, making a nervous system superfluous.

A sting from an unknown jellyfish species associated with persistent symptoms and raised troponin I levels.

We describe a patient stung by an unknown jellyfish species offshore in Far North Queensland. The sting caused immediate and severe pain, multiple whip-like skin lesions and constitutional symptoms. The jellyfish tentacular nematocysyts were similar to, but distinct from, those of Carukia barnesi, a cause of the 'Irukandji' syndrome. The patients symptoms largely resolved over seven months and were associated with elevated cardiac troponin levels, in the absence of other evidence of cardiac disease. This case highlights the envenomation risks associated with marine recreation, and the need for critical evaluation of cardiac troponin assays and for further research in marine toxicology.