SN Comprehensive Clinical Medicine (2020) 2:2288–2292
https://doi.org/10.1007/s42399-020-00490-y

MEDICINEMarine Envenomation
Toru Hifumi 1

2& Yoshimune Fukuchi & Norio Otani

1

Accepted: 25 August 2020 / Published online: 4 September 2020
# The Author(s) 2020

Abstract
With global warming and an increasing frequency of human interaction with venomous marine organisms, physicians are likely
to encounter more cases of marine envenomation in clinical practice in Japan and around the world. Few review articles regarding
the clinical characteristics of marine envenomation have been published and there has been no comprehensive review of available
antivenoms, which are the definitive treatment. We discuss the epidemiology, venom activity, clinical symptoms, diagnosis, andtreatment of marine envenomation by the Okinawan box jellyfish, stonefish, Portuguese man-of-war, geography cone, and blueringed octopus. A comprehensive review of available antivenom treatments is also presented.
Keywords Marine envenomation . Epidemiology . Diagnosis . Treatment . Antivenom

Background
The annual incidence of marine envenomation in Florida andeastern Australia is approximately 100,000 [1]. Previous clinical reports of marine envenomation include an outbreak ofPortuguese man-of-war envenomation in southeastern Brazil[2] and a compilation of human injuries and fatalities due toenvenomation by the geography cone, which is the most dangerous species to humans [3]. Currently, it appears that theincidence of marine envenomation in Japan and around theworld is likely to increase due to global warming and increasing frequency of human interactions with venomous marineorganisms [4–6]. However, few clinical reviews of marine
envenomation have been published [7–9], and there has been
no comprehensive review of available antivenoms, which areThis article is part of the Topical Collection on Medicine* Toru Hifumi
hifumitoru@gmail.com
Yoshimune Fukuchi
fukuchyo@pref.okinawa.lg.jp
Norio Otani
oono@luke.ac.jp
1

Department of Emergency and Critical Care Medicine, St. Luke’s
International Hospital, Emergency Medical Center, 9-1 Akashi-cho,
Chuo-ku, Tokyo 104-8560, Japan

2

Okinawa Prefectural Institute of Health and Environment,
Okinawa, Japanthe definitive treatment. In this review, we discuss the epidemiology, venom activity, clinical symptoms, diagnosis, andtreatment of marine envenomation by the box jellyfish, stonefish, Portuguese man-of-war, geography cone, and blueringed octopus and also provide a comprehensive review ofavailable antivenoms.

Main Text
Box Jellyfish
Scientific name: Chironex yamaguchii
Appearance: The diameter of the hood is approximately
10–14 cm, and the body length can reach approximately 1.5 m
with tentacles extended. This jellyfish possesses seven tentacles attached to four arms (Fig. 1).
Epidemiology: Jellyfish appear in large numbers in swimming areas, particularly inlets and beaches where waves aresubdued. Several jellyfish sting cases have been reported in
the literature [10–12] and recently, Hifumi et al. comprehensively described the clinical characteristics of jellyfish stings
in Japan [13]. One urban emergency department in Hawaii
experiences approximately 20 jellyfish sting cases annually[14]. The annual number of cases in Japan is relatively small
compared with the annual incidence of approximately
100,000 in Florida and eastern Australia [1].
Venom activity and clinical symptoms: Box jellyfish
venom has hemolytic and neurotoxic effects and causes skinnecrosis and hypotension.

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Fig. 1 Box Jellyfish. Photograph courtesy of the Okinawa Prefectural
Institute of Health and Environment

Diagnosis: No definite diagnostic criteria exist. Diagnosisof jellyfish stings is based on either the patient’s history or
positive identification of the responsible jellyfish presented by
the patient [13]. Severe stings result in systemic envenomation, which may result in Irukandji syndrome and/or anaphylaxis, and most often require hospital admission [15].
Treatment: Applying vinegar to any tentacles remaining
on the skin prior to removal can deactivate unfired nematocysts. After vinegar application, the tentacles may be gentlyremoved. Cardiac arrest and cardiogenic shock are appropriate
indications for antivenom administration [16]; earlier administration of antivenom may neutralize the venom.
Prevention: Box jellyfish are a common hazard, as they
are translucent and difficult to see through the water’s surface.
Swimming within an area protected by anti-jellyfish barrier
netting is recommended.

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Fig. 2 Stonefish. Photograph courtesy of the Okinawa Prefectural
Institute of Health and Environment

by individuals fishing for food, since stonefish are eaten insome regions. Venom from the genus Synanceia has hyaluronidase activity and causes hemolysis, hypotension, andnerve paralysis.
Diagnosis: Currently, there are no definitive diagnostic
criteria for stonefish envenomation. The diagnosis of stonefish
envenomation is based on the patient’s history or the positive
identification of the stonefish presented by the patient [24].
Treatment: It is important to warm the site of stonefish
stings as this helps to relieve pain. Warming the affected area
to approximately 43 °C is recommended. Antivenom is available and consists of the purified F(ab)2 fragment of equine
IgG antibodies raised against the venom of Synanceia
trachynis [26]. In a study conducted in Hong Kong, 25% ofpatients received treatment with antivenom [21].
Prevention: Use thick rubber-soled footwear to prevent
spine penetration.

Stonefish
Scientific name: Synanceia verrucosa
Appearance: Reef stonefish have an overall body lengthof approximately 40 cm and are difficult to see, as they blend
in with rocks on the seabed. Their spines are tough and able topenetrate rubber-soled boots and wetsuits (Fig. 2).
Epidemiology: Stonefish stings, including those from reefstonefish, are a common injury seen in the emergency room.
They are primarily found in the coastal waters of the IndoPacific region, including the USA, Australia, Malaysia, Hong
Kong, and Singapore [17–21]. Few Japanese studies of stonefish envenomation have been reported [22, 23]; however,Hifumi et al. recently reported 15 cases over a 5-year observation period [24] and two deaths related to stonefish envenomation have been reported in Japan [25].
Venom activity and clinical symptoms: Fatalities
resulting from reef stonefish stings have been reported inOkinawa prefecture. These injuries may have been sustained

Portuguese Man-of-War
Scientific name: Physalia physalis utriculus
Appearance: A lovely blue hue. Also called “blue bottles,”they have a bluish-white floating hood from which tentacles
extend to reach a length of 10–20 m [27]. The Portugueseman-of-war is also called the “electric jellyfish” because its
tentacles contain many nematocysts that induce a strong sensation akin to an electric shock (Fig. 3).
Epidemiology: An outbreak of Portuguese man-of-war envenomation in southeastern Brazil was reported in 2013 [2]. In
addition, a massive outbreak at Yuigahama Beach, Japan, occurred in 2018.
Venom activity and clinical symptoms: Portuguese manof-war venom induces hemolysis, swelling, and necrosis andcan be lethal. Extreme pain is experienced immediately following the sting. Areas of skin that contact the man-of-war’s

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Fig. 3 Portuguese man-of-war. Photograph courtesy of the Okinawa
Prefectural Institute of Health and Environment

tentacles form swollen welts that appear as a linear papularrash.
Diagnosis: Currently, there are no definitive diagnostic
criteria for Portuguese man-of-war envenomation. The diagnosis is based on the patient’s history or positive identificationof the Portuguese man-of-war presented by the patient.
Treatment: Use sea or tap water to wash away any tentacles that remain wrapped around the body. If tentacles cannot
be rinsed off, gently remove them with the fingertips. Do notuse vinegar as you would for box jellyfish stings because thispromotes nematocyst firing in the Portuguese man-of-war.
Use strong topical steroids if inflammation at the site of thesting is severe.
Prevention: Do not enter the ocean when alerted to thepresence of jellyfish. Swim in areas protected by an antijellyfish barrier net. Minimize exposure of unprotected skinas much as possible.

Geography Cone
Scientific name: Gastridium geographus
Appearance: The shell of the geography cone grows to asize of 10–13 cm and it beautifully intertwines clouds of crimson with a fine mesh pattern (Fig. 4).
Epidemiology: Araki et al. reported 18 cases fromOkinawa prior to 1991; 13 were from G. geographus envenomation, of which 4 were fatal [28]. Kohn reported 43 cases ofvictim, of which 15 (35%) were fatal [3].
Venom activity and clinical symptoms: G. geographus is
the most dangerous species known to humans [3]. Conotoxins
target receptors and channels that mediate neuromuscular
blockade [29]. Paralysis at the site of injury, dizziness, double
vision, numbness of the mouth, and other symptoms mayoccur. In severe cases, ventilatory support may be required.
Diagnosis: Currently, there are no definitive diagnostic
criteria for geography cone envenomation. The diagnosis isbased on the patient’s history or the positive identification of
the geography cone presented by the patient.

Fig. 4 Geography cone. Photograph courtesy of the Okinawa Prefectural
Institute of Health and Environment

Treatment: The wound should be soaked in hot water(maximum 45 °C) for 30–90 min [7]. Standard medical careshould be provided. Mechanical ventilation may be requiredin severe cases. There is no antivenom for a geography conesting. Treatment is supportive until the toxins become
inactive.
Prevention: Do not pick up seashells carelessly.

Blue-Ringed Octopus
Scientific name: Hapalochlaena fasciata
Appearance: A small octopus approximately 10 cm inlength. The skin is yellow and spotted with blue circles [30](Fig. 5).
Epidemiology: H. fasciata is most commonly foundaround intertidal rocky shores and coastal waters between
Australia and through the Pacific Ocean north to Japan.

Fig. 5 Blue-ringed octopus. Photograph courtesy of the Okinawa
Prefectural Institute of Health and EnvironmentSN Compr. Clin. Med. (2020) 2:2288–2292
Table 1 Clinical availability andindication of antivenom

Clinicalavailability
Indication

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Box jellyfish

Stonefish

Physalia
physalisConus
geographus

Bluelinedoctopus

Yes

Yes

NoNo

No

Cardiacarrest or
cardiogenic shock

Systemic effects and those with severe
pain that is unresponsive to hot water
immersion and analgesia–––

Venom activity and clinical symptoms: Blue-ringed octopus venom includes tetrodotoxin and can cause respiratory
muscle paralysis [30].
Treatment: Standard medical care should be provided.
Mechanical ventilation may be required in severe cases.
Prevention: The blue-ringed octopus may be found during
clam digging when large rocks are overturned. They should
not be touched with bare hands.

Funding This research was supported by the Research Program on
Emerging and Re-emerging Infectious Disease from the Japan Agency
for Medical Research and Development (AMED). This research received
no external funding.
Data Availability Not applicable.

Compliance with Ethical Standards
Ethical Approval and Consent to Participate Not applicable.

Antivenom
Clinical availability of antivenoms and indications for theiruse are summarized in Table 1 [31]. Only antivenoms forjellyfish and stonefish stings are available. Both aremanufactured by immunizing horses against unbound venom;
therefore, adverse reactions, including anaphylaxis, should be
anticipated and prepared for. The incidence of adverse reactions to snake antivenom produced from horse serum is 2.4–
11% [32]. The establishment of airway, breathing, and circulation is required before using antivenom. This section may be
divided by subheadings. It should provide a concise and precise description of the experimental results, their interpretation, and the experimental conclusions that can be drawn.

Consent for Publication Not applicable.
Competing Interests The authors declare that they have no competinginterests.
Open Access This article is licensed under a Creative Commons

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you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes weremade. The images or other third party material in this article are includedin the article's Creative Commons licence, unless indicated otherwise in a
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Conclusions

References

This review provides a comprehensive summary of the available information regarding marine envenomation in humans.
Data continue to be collected on a case-by-case basis as nolarge-scale epidemiological studies have been conducted todate. Clinical marine envenomation research is severely lacking. Since more cases of marine envenomation will undoubtedly occur in the future, emergency physicians need to beaware of their diagnosis and management.

1.

Authors’ Contributions Conceptualization, T.H.; writing—original draft
preparation, T.H.; writing—review and editing, Y.F and N.O; visualization, T.H.; supervision, Y.F. and N.O. All authors have read and agreed tothe published version of the manuscript.

5.

2.

3.

4.

6.

Burnett JW. Human injuries following jellyfish stings. Md Med J.
1992;41:509–13.
Haddad V Jr, Virga R, Bechara A, Silveira FL, Morandini AC. An
outbreak of Portuguese man-of-war (Physalia physalis - Linnaeus,1758) envenoming in Southeastern Brazil. Rev Soc Bras Med Trop.
2013;46:641–4.
Kohn AJ. Human injuries and fatalities due to venomous marinesnails of the family Conidae. Int J Clin Pharmacol Ther. 2016;54:
524–38.
Hifumi T. Treatments of venomous snake bites. Nihon Iji Shinpo.
2015;4772:56.
Xu Y, Ramanathan V, Victor DG. Global warming will happen
faster than we think. Nature. 2018;564:30–2.
Needleman RK, Neylan IP, Erickson TB. Environmental and ecological effects of climate change on venomous marine and

2292

7.
8.
9.
10.

11.

12.
13.

14.

15.
16.
17.

18.
19.

20.

SN Compr. Clin. Med. (2020) 2:2288–2292
amphibious species in the wilderness. Wilderness Environ Med.
2018;29:343–56.
Hornbeak KB, Auerbach PS. Marine envenomation. Emerg MedClin North Am. 2017;35:321–37.
Little M, Pereira P, Mulcahy R, Cullen P. Marine envenomation.
Emerg Med (Fremantle). 2001;13:390–4.
Perkins RA, Morgan SS. Poisoning, envenomation, and trauma
from marine creatures. Am Fam Physician. 2004;69:885–90.
Kawahara M, Uye S, Burnett J, Mianzan H. Stings of edible jellyfish (Rhopilema hispidum, Rhopilema esculentum andNemopilema nomurai) in Japanese waters. Toxicon. 2006;48:
713–6.
Manabe Y, Mabuchi T, Kawai M, Ota T, Ikoma N, Ozawa A, et al.
A case of delayed flare-up allergic dermatitis caused by jellyfish
sting. Tokai J Exp Clin Med. 2014;39:90–4.
Ohtaki N, Satoh A, Azuma H, Nakajima T. Delayed flare-up reactions caused by jellyfish. Dermatologica. 1986;172:98–103.
Hifumi T, Fukuchi Y, Otani N, Kondo Y, Kitamoto T, Kobayashi
K, et al. Clinical characteristics of jellyfish stings in Japan. AcuteMed Surg. 2020;7:e469.
Ping J, Onizuka N. Epidemiology of jellyfish stings presented to an
American urban emergency department. Hawaii Med J. 2011;70:217–9.
Fenner PJ. Jellyfish responsible for Irukandji syndrome. QJM.
2006;99:802–3 author reply 3-4.
Isbister GK. Jellyfish stings. Aust Prescrib. 2007;30.
Tay TK, Chan HZ, Ahmad TS, Teh KK, Low TH, Wahab NA.
Stonefish envenomation of hand with impending compartment syndrome. J Occup Med Toxicol. 2016;11:23.
Ngo SY, Ong SH, Ponampalam R. Stonefish envenomation presenting to a Singapore hospital. Singap Med J. 2009;50:506–9.
Prentice O, Fernandez WG, Luyber TJ, McMonicle TL, Simmons
MD. Stonefish envenomation. Am J Emerg Med. 2008;26:972 e1–2.
Isbister GK. Venomous fish stings in tropical northern Australia.
Am J Emerg Med. 2001;19:561–5.

21.

Poon KM. CHVNaMT. A 10-year retrospective review of stonefish
sting injury in Hong Kong. Hong Kong J Emerg Med. 2019:1–4.
22. Yamamoto R, Suzuki M, Hori S, Aikawa N. Stonefish "Okoze"
envenomation during food preparation. Keio J Med. 2010;59:19–
22.
23. Hashimoto A, Nakao A, Inoue T, Fuse C, Yamada T, Hirata J, et al.
Incorrect first aid treatment information about stonefish envenomation on medical websites. Chudoku Kenkyu. 2013;26:292–4.
24. Hifumi T. Clinical characteristics of stonefish “Oni-DarumaOkoze” envenomation in Japan. Acute Med Surg. 2020;7:e496.
25. Azama Y, Morine N, Tsuha A, Kudaka J. Injury cases by Marine A
nimalnimals in Okinawa , Japan in 2012–2013. Okinawa Eisei
kenkyujo-Hou. 2016:33–7.
26. Church JE, Hodgson WC. Stonefish (Synanceia trachynis)
Antivenom: in vitro efficacy and clinical use. J Toxicol Toxin
Rev. 2003:69–76.
27. Munro C, Vue Z, Behringer RR, Dunn CW. Morphology and development of the Portuguese man of war, Physalia physalis. Sci
Rep. 2019;9:15522.
28. Araki Y, Fukumura K, Yoshiba S. Conus-stings in Okinawa. Jpn J
Trop Med Hyg. 1992;20:63–4.
29. Espiritu DJ, Watkins M, Dia-Monje V, Cartier GE, Cruz LJ,Olivera BM. Venomous cone snails: molecular phylogeny andthe generation of toxin diversity. Toxicon. 2001;39:1899–916.
30. Townsend KA, Altvater J, Thomas MC, Schuyler QA, Nette GW.
Death in the octopus’ garden: fatal blue-lined octopus
envenomations of adult green sea turtles. Mar Biol. 2012;159:689–95.
31. CSL Antivenom Handbook. http://www.toxinology.com/generic_static_files/cslavh_antivenom_stonefish.html
32. Hifumi T, Sakai A, Kondo Y, Yamamoto A, Morine N, Ato M,
et al. Venomous snake bites: clinical diagnosis and treatment. J
Intensive Care. 2015;3:16.
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