Aquatic animals include those found in both salt and freshwater. Most are harmless; however, some jellyfish and venomous fish can produce stings that can be painful and cause minor or severe Allergic reactions. Stinging injuries are a common occurrence on many beaches worldwide and are problematic for people whose livelihoods depend on activities which bring them into contact with venomous fish or jellyfish. For bite injuries from a non-venomous aquatic animal, see Cuts and grazes or Severe bleeding.
Guidelines
- For jellyfish stings, heat may relieve the pain. *
- Any remaining stinging cells from a jellyfish should be removed from the skin. *
Good practice points
- First aid providers should protect themselves from being stung when removing any tentacles or stinging cells from the skin.
- To remove visible jellyfish tentacles, use tweezers. To remove jellyfish stinging cells, first aid providers may cover the stinging cells with sand or shaving foam and then scrape them off with cardboard or a bank card.
- The first aid provider may immerse the injury in hot water (up to a maximum of 45°C/113°F) for at least 20 to 30 minutes or apply a heat pack.
- If a heat pack or hot water are not available, it is reasonable to apply a cold pack to relieve the pain.
- The choice of an agent applied to a jellyfish injury should be specific to the jellyfish.
> Salt water may relieve pain for some jellyfish stings.
> Vinegar may relieve pain for some jellyfish stings (Physalia species). Do not apply vinegar to a bluebottle jellyfish, as it will cause the venom to spread further. - Aluminium sulphate, meat tenderizer, or cold, fresh water should not be used for pain relief.
- First aid providers should discourage the person from rubbing the site of the injury.
- In areas with deadly aquatic animals, when a person has been bitten or stung, medical care should be accessed immediately. This is also the case if the person experiences any signs of a severe Allergic reaction. First aid providers should assess the person’s airway, breathing and circulation while providing care for any other symptoms caused by the injury.
- There is a risk of tetanus from an aquatic animal injury, so tetanus vaccinations might be suitable as a preventative measure.
- If warmth or pain develop around the site of the injury, this is an indication of infection and the person should seek medical advice immediately. The injury should be monitored as infection can happen in the hours or days after the bite occurs.
Chain of survival behaviours
Prevent and prepare
- Injuries from venomous marine and freshwater animals can be related to livelihoods and economic activity in addition to tourism and leisure, so target preventative measures and education at local people at risk as well as visitors.
- For people at risk, protective clothing should be worn.
- Follow local guidelines about the risks of entering the water.
Early recognition
The person has pain associated with puncture wounds from the stinging cells. You may be able to see stinging cells attached to the skin.
The person may develop a mild or severe Allergic reaction following a sting. Observe the person closely for any development of an allergic reaction. A rash can be more difficult to see on black or brown skin (Nolen, 2020). Checking lighter areas of skin such as the palms of hands or soles of feet may help you to see it.
First aid steps
- If necessary, remove all of the stinging cells from the person’s skin. Protect yourself from being stung as you do this.
- Apply heat to the site of the injury for 20-30 minutes. You could immerse the injury in hot water or apply a heat pack.
- Advise the person to seek medical care if there is a risk of tetanus or persistent pain that is not relieved by treatment.
Access help
- If the sting injury is from a deadly species of aquatic animal, or if there is any doubt, access EMS immediately.
- If the person experiences a severe Allergic reaction, access help immediately.
Recovery
Monitor for signs of infection. The skin may become red, purple, or darker, as well as warm and painful at the site of the sting. This should improve over the course of a day or two. However, if it gets progressively worse, the person should seek medical advice as this could be a sign of infection.
Education considerations
Context considerations
- Consult local aquatic institutions and water rescue associations to identify the most common and dangerous aquatic animals in the region. Include the first aid response for these species only in your programmes.
- If local authorities recommend applying medication to aquatic injuries (such as steroid ointments or lidocaine gels), ensure that this action is in line with the local legislation concerning first aid providers.
- In settings where groups at risk of aquatic animal injuries are defined by employment or livelihoods, provide targeted education programmes on this topic using facilitators from the affected population (De Aquino et al., 2015).
- Work with local aquatic institutions and local authorities to ensure public notices are displayed which alert people to the dangers of being stung by an aquatic animal, and the appropriate first aid.
Learner considerations
- Adapt education to the literacy level of the learner group, being aware that illiteracy might be a factor for some at-risk groups (De Aquino et al., 2015).
- Visitors to areas where there is a risk of being stung might not be informed about the risks. Education in the form of public posters could be necessary. Where possible these should include clear illustrations and an emergency number to call for help, to avoid language barriers.
Facilitation tips
- Emphasise preventative measures, such as identifying warning signs at the beach or wearing protective clothing and workwear when doing aquatic activities.
- If possible, facilitators should be familiar with the aquatic environment about which they are educating as this will allow them to add local knowledge about tides or dangerous places to swim, as well as have local knowledge about how best to get help when necessary (Aquino et al., 2016).
- When educating people in locations where incidences of injury are high, identify and share knowledge on any variations in times or locations where the risk from a particular species is greater (e.g. if injuries occur more frequently at certain times of day or night, or are more common in shallow or deep water).
Facilitation tools
- Share photos of venomous aquatic animals that are prevalent locally and provide basic information such as where they can be found.
- Share photos of wounds with stinging cells or sting fragments to help learners identify what these look like.
- Ensure learners know to use hot water at the optimum temperature range (around 45°C) and what this feels like. Encourage learners to reflect on how they would access hot water rapidly when in a typical aquatic environment, such as a beach or lake.
- Demonstrate the use of a bank card or similar flat object for stinging cell removal.
Learning connections
- Reference could be made to similarities with Insect sting
- Highlight the risks of burning the skin if the water temperature is too high.
- Some people with a sting may experience an Allergic reaction or anaphylaxis.
Scientific foundation
Evidence for marine animal injuries was reviewed in 2015 and 2019 and the guidelines have been updated accordingly. Additional literature was sought to embellish the educational context, and this led to the inclusion of freshwater animal injuries. However, a scientific review has not been undertaken for freshwater animal injuries.
Systematic review
The Centre for Evidence-Based Practice (CEBaP) made evidence summaries for several different treatments including a selection of topical agents, hot or cold-water immersion and pressure immobilisation.
Jellyfish – topical agents
CEBaP identified moderate-certainty evidence (downgraded for imprecision due to the low number of events) from three experimental studies showing that sting inhibitor lotion resulted in a statistically significant decrease in the number of stings, pain and erythema, compared to the placebo (conventional sunscreen lotion).
The use of vinegar as a method to prevent further nematocyst discharge has only been studied in in vitro studies or animal studies. No controlled studies with humans are available.
Jellyfish – hot water
CEBaP identified low-certainty evidence (downgraded for risk of bias and limited sample size) from three experimental studies showing that hot water or a hot pack resulted in a statistically significant decrease in pain, compared to an ice pack, vinegar or papain meat tenderiser. However, a difference in time to stopping the pain could not be demonstrated. A statistically significant decrease of itchiness, red mark or minor rash, raised and red or wheal reaction or bullous reaction, using hot water compared to an ice pack, vinegar or papain meat tenderizer, could not be demonstrated in two studies.
Jellyfish – pressure immobilisation
CEBaP could not identify any human studies about the use of pressure immobilisation for jellyfish stings.
Jellyfish – seawater
A statistically significant decrease of pain could not be demonstrated using salt water compared to fresh water, sting-aid or Adolph’s meat tenderiser. Evidence is of low certainty and the results of this study are imprecise due to the limited sample size and large variability of results.
Non-systematic reviews
Ward et al. (2012) l found that if envenomation is from a Physalia species of jellyfish found in North America and Hawaii, vinegar may be beneficial.
Nomura et al. (2002) conducted a randomised paired comparison trial of treatments for acute jellyfish stings and found that the most effective treatment for the Carybdea alata species is hot water.
Education review
One study was found to inform education considerations for this topic. Aquino et al. (2016) identified a high proportion (at least 30%) of the target group experienced injuries from a specific type of venomous freshwater fish because of their livelihoods. Their injuries resulted in a high frequency of trauma and venomous toxins leading to systemic complications. The study identified a high level of inappropriate treatment being applied. Combined, this had a direct impact on the ability of the injured people to work and emphasised the importance of education. The target group had a high degree of illiteracy and limited availability for extensive classroom-based learning. The study also highlighted the importance of facilitators who understand the local context (as opposed to facilitators from ‘outside’). The finding that secondary infections and complications related to a lack of knowledge of effective treatment demonstrate the importance of tailoring educational content to specific target groups. It also places equal emphasis on prevention and treatment during first aid education, which can be applied more broadly to this topic.
References
Systematic reviews
Centre for Evidence-Based Practice. (2016). Evidence summary: Jellyfish – Hot water. Belgian Red Cross, Flanders. Available from: https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Centre for Evidence-Based Practice. (2019). Evidence summary: Jellyfish – Sting inhibitor lotion. Belgian Red Cross, Flanders. Available from: https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Centre for Evidence-Based Practice. (2016). Evidence summary: Jellyfish – Vinegar. Belgian Red Cross, Flanders. Available from:
https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Centre for Evidence-Based Practice. (2016). Evidence summary: Jellyfish – Salt water. Belgian Red Cross, Flanders. Available from:
https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Centre for Evidence-Based Practice. (2019). Evidence summary: Jellyfish – Compression. Belgian Red Cross, Flanders. Available from: https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Non-systematic reviews
Nolen, L. (2020). How medical education is missing the bull’s-eye. The New England Journal of Medicine, 382, 2489–2491. DOI https://www.nejm.org/doi/full/10.1056/NEJMp1915891
Nomura, J. T., Sato, R. L., Ahern, R. M., Snow, J. L., Kuwaye, T. T., & Yamamoto, L. G. (2002). A randomized paired comparison trial of cutaneous treatments for acute jellyfish (Carybdea alata) stings. The American journal of emergency medicine, 20(7), 624-626.
Ward, N. T., Darracq, M. A., Tomaszewski, C., & Clark, R. F. (2012). Evidence-based treatment of jellyfish stings in North America and Hawaii. Annals of Emergency Medicine, 60(4), 399-414.
Education reference
Aquino, G. N. D., Souza, C. C., Haddad Junior, V., & Sabino, J., (2016). Injuries caused by the venomous catfish pintado and cachara (Pseudoplatystoma genus) in fishermen of the Pantanal region in Brazil. Anais da Academia Brasileira de Ciências, 88(3), 1531-1537. Retrieved from https://www.scielo.br/scielo.php?pid=S0001-37652016000401531&script=sci_arttext
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