What are the common causes of coral skin infections. How do coral scrapes and cuts manifest. What are the best prevention and first aid methods for coral injuries. How can divers avoid complications from coral-related wounds.

The Nature of Coral Skin Infections: More Than Just a Scratch

Coral skin infections are a common concern for divers and snorkelers, often underestimated in their potential severity. These injuries, while seemingly minor at first glance, can lead to prolonged healing periods and significant discomfort. The Divers Alert Network (DAN) reports receiving approximately one inquiry per week related to coral contact injuries, highlighting the frequency of this issue in the diving community.

What makes coral injuries unique? Unlike typical scrapes or cuts, coral injuries involve contact with living marine organisms. This interaction can introduce various antigens and substances into the wound, triggering an acute inflammatory process and potential infection. As a result, these injuries can have a latent evolution, taking weeks or even months to heal fully.

Mechanisms of Coral-Related Injuries: Understanding the Risks

The mechanism of coral-related injuries is multifaceted. Corals are covered by soft living tissues, but in the case of stony corals, a rigid, abrasive structure lies underneath. When a diver or snorkeler comes into contact with coral, this combination of soft and hard structures can easily tear skin and introduce foreign material into the wound.

Why do coral cuts tend to fester? The introduction of foreign material from the coral can significantly prolong the wound-healing process. The body’s immune response to these foreign substances can result in an acute inflammatory process, leading to infection and delayed healing. In some cases, granulomas may form if debris from the original wound remains in the tissue, causing persistent itching and discomfort.

Types of Coral Injuries

• Scrapes from stony corals
• Cuts from sharp-edged coral
• Stings from fire coral (a hydroid)
• Abrasions from barnacles

Manifestations of Coral Skin Infections: Recognizing the Symptoms

The severity and symptoms of coral skin infections can vary widely depending on several factors. What determines the extent of the reaction to coral contact? The presence and amount of toxins, the size and location of the abrasion, and the pre-existing sensitivity of the injured person all play crucial roles in determining the severity of the reaction.

What are the most common symptoms of coral skin infections?

• Burning sensation
• Pain
• Itching
• Rash (particularly with hydroid contact)
• Blistering (typically with fire coral)

In the case of fire coral, which belongs to the class Hydrozoa, the reaction can be particularly intense. Fire corals contain nematocysts, which can cause envenomation even with a simple touch. Blistering typically appears a few hours after contact and may resolve within a few days. However, it’s important to note that these injuries often have a characteristic pattern of relapse, with symptoms potentially returning a week or two after apparent healing.

Prevention Strategies: Minimizing the Risk of Coral Injuries

Prevention is key when it comes to coral skin infections. How can divers and snorkelers protect themselves from coral injuries?

1. Avoid contact with coral or any other living marine creature whenever possible.
2. Wear protective gear such as wetsuits or dive skins.
3. Be aware of currents and other divers to avoid accidental contact.
4. Carry a marine animal first aid kit during ocean dives.
5. Educate yourself on marine life identification and first aid techniques.

Why is wearing protective gear so important? Even if you’re careful, unexpected currents or other divers can potentially push you into contact with coral. A wetsuit or dive skin provides a crucial barrier between your skin and potentially harmful marine organisms.

First Aid for Coral Injuries: Immediate and Ongoing Care

Proper first aid is crucial for minimizing the impact of coral injuries and preventing complications. What steps should be taken immediately after a coral injury occurs?

1. Thoroughly clean the wound with soap and water, scrubbing vigorously.
2. Flush the wound with a solution of half-strength hydrogen peroxide in water, followed by a clean water rinse.
3. Apply a thin layer of antiseptic ointment and cover with a sterile, non-adherent dressing.
4. Clean and redress the wound twice daily.

For wounds that develop a crust, a wet-to-dry dressing technique can be effective. How does this technique work? Apply a dry sterile gauze pad soaked in saline or diluted antiseptic solution to the wound. Allow it to dry, then remove the bandage, which should lift away dead and dying tissue. Repeat this process once or twice daily until the dressing becomes non-adherent.

Signs of Infection to Watch For

• Extreme redness
• Red streaks on the extremity
• Increased pain
• Fever
• Presence of pus
• Swollen lymph glands

If any of these signs appear, it’s crucial to consult a healthcare professional promptly. Why is quick action important? Some marine bacteria, such as Vibrio species, can cause severe infections, particularly in individuals with compromised immune systems.

Complications of Coral Skin Infections: Beyond the Initial Injury

While many coral injuries heal without incident, complications can occur. What are the potential complications of coral skin infections?

• Delayed wound healing
• Persistent inflammation
• Secondary bacterial infections
• Granuloma formation
• Coral poisoning (in severe cases)

Coral poisoning is a particularly serious complication that can occur with extensive abrasions or cuts from highly toxic coral species. What are the symptoms of coral poisoning?

• Poor wound healing
• Continuous pus drainage
• Swelling around the wound
• Swollen lymph glands
• Fever
• Chills
• Fatigue

If these symptoms develop, immediate medical attention is necessary to prevent potentially severe complications.

Special Considerations: Fire Coral and Other Hydroids

Fire coral, despite its name, is not actually a true coral but a marine organism belonging to the class Hydrozoa. What makes fire coral injuries different from other coral-related wounds?

Fire coral contains nematocysts, specialized cells that can inject venom upon contact. This means that even a light touch can result in a painful sting and subsequent skin reaction. The initial symptoms may include:

• Intense burning sensation
• Redness and swelling
• Blistering (typically appearing hours after contact)

One of the unique characteristics of fire coral injuries is their tendency to relapse. Why do fire coral injuries often recur? The exact mechanism is not fully understood, but it’s thought to be related to the body’s ongoing immune response to the venom components. Divers may experience a resurgence of symptoms a week or two after the initial injury appeared to be healing.

Treatment for Fire Coral Injuries

How should fire coral injuries be treated?

1. Rinse the affected area with seawater (avoid fresh water as it can cause nematocysts to fire)
2. Apply vinegar to the area for at least 30 seconds to neutralize any unfired nematocysts
3. Remove any visible tentacles with tweezers
4. Apply a cold pack to reduce pain and swelling
5. Use a topical corticosteroid cream to manage inflammation
6. Take oral antihistamines to reduce itching and allergic reactions

In cases of severe reactions or if symptoms persist, seeking medical attention is advisable. A healthcare professional may prescribe stronger anti-inflammatory medications or antibiotics if a secondary infection develops.

Long-Term Management and Follow-Up Care

The healing process for coral skin infections can be prolonged, often requiring ongoing care and attention. What steps should divers take for long-term management of coral injuries?

1. Continue wound care as directed, even if healing seems slow
2. Monitor the wound site for any signs of infection or unusual changes
3. Protect the affected area from further injury or sun exposure
4. Consider using scar-reducing treatments once the wound has fully closed
5. Follow up with a healthcare provider if healing stalls or new symptoms develop

Why is continued monitoring so important? Coral injuries can have a latent evolution, meaning complications or delayed reactions may occur weeks or even months after the initial injury. Vigilance in wound care and observation can help prevent or quickly address any emerging issues.

Scar Management

As coral injuries heal, they may leave behind noticeable scars. What options are available for minimizing scarring from coral injuries?

• Silicone-based scar sheets or gels
• Topical vitamin E or other scar-reducing creams
• Gentle massage of the healed area to promote collagen remodeling
• Sun protection to prevent hyperpigmentation of the scar tissue

It’s important to note that scar treatment should only begin once the wound has fully healed and closed. Premature treatment can interfere with the healing process and potentially lead to complications.

Diving Safety and Environmental Conservation

While understanding and treating coral injuries is crucial, prevention through responsible diving practices is equally important. How can divers protect both themselves and the delicate coral ecosystems?

1. Master buoyancy control to avoid accidental contact with coral
2. Use reef-safe sunscreen to minimize chemical damage to marine environments
3. Participate in coral conservation efforts and education programs
4. Choose eco-friendly dive operators who prioritize reef protection
5. Report any observed damage or threats to coral reefs to local authorities

Why is coral conservation so crucial? Coral reefs are not only vital ecosystems supporting marine biodiversity but also provide essential services such as coastal protection and are significant for tourism economies. By practicing responsible diving, we can help preserve these invaluable natural resources for future generations.

Educating Fellow Divers

Experienced divers play a crucial role in educating newcomers about coral safety and conservation. What are some ways to spread awareness about coral protection and injury prevention?

• Share personal experiences and lessons learned from coral injuries
• Mentor new divers in proper buoyancy techniques and reef etiquette
• Participate in or organize local marine conservation events
• Use social media to share information about responsible diving practices
• Support dive shops and operators that prioritize environmental education

By fostering a culture of respect and caution around coral reefs, the diving community can significantly reduce the incidence of coral injuries while also contributing to the preservation of these fragile ecosystems.

Coral Scrapes and Cuts – Divers Alert Network

Cuts and scrapes are the most common injuries incurred by divers and snorkelers. DAN receives about one inquiry a week related to someone who has come into contact with coral. A burning sensation, pain and itching are common and may also be accompanied by a rash. These injuries can have a latent evolution and take weeks or months to heal, confusing both patients and clinicians.

Mechanisms of Injury

Soft living tissues cover the surface of corals. In the case of stony corals, the rigid (abrasive) structure underneath makes the coral’s soft tissue easy to tear and get into the scrape or cut. Foreign material can prolong the wound-healing process since the different antigens and substances cause an acute inflammatory process and infection. Cuts and scrapes from sharp-edged coral and barnacles tend to fester and may take weeks or even months to heal. Granulomas can form if debris from the original wound remains in the tissue. The body attempts to remove it, resulting in an itchy rash or papule (small, raised, tender bump) that lasts for some time before the body eliminates it.

While most “raspberries” generally heal quickly, skin abrasions from a marine environment can sometimes be more challenging to treat than those we get from outdoor activities such as baseball or bicycling. Whether it is a coral, a rock or a wreck, they all share a common factor: They are covered by living marine organisms, which makes coral cuts and scrapes unique.

Manifestations

The extent of the reaction depends on the presence and amount of toxins, the size and location of the abrasion and the pre-existing sensitivity of the injured person. The most common manifestations are a burning sensation, pain and itching. A rash may accompany the injury if the coral is a hydroid, such as fire coral.

Most animals of class Hydrozoa become hydroids as a life stage. They are predominantly colonial, and while most of them are marine creatures, you can find a few species in freshwater environments.

Fire corals are cnidarians, so they contain nematocysts. Touching them with a simple rub can cause mechanical activation and envenomation. The manifestation is usually blistering, which typically appears a few hours after contact. They typically resolve in a few days, but it is quite common for these injuries to relapse within a week or two after what seemed to be healing progress. This delayed reaction is typical of these types of envenomations.

Prevention

When underwater, try to avoid contact with coral or any other living creature. Whenever possible, wear a wetsuit or dive skin to protect yourself if you are accidentally pushed into coral by another diver or a current. Ocean divers should consider a marine animal first aid kit for their travels. Ready supplies will speed up the time to properly administer first aid for injuries. Additionally, for divers who want to learn more about the various marine life injuries, there are courses in marine life identification, first aid courses and a variety of books and publications available.

First Aid

• Scrub the cut vigorously with soap and water, and then flush the wound with large amounts of water.
• Flush the wound with a half-strength solution of hydrogen peroxide in water. Rinse again with water.
• Apply a thin layer of antiseptic ointment, and cover the wound with a dry, sterile and non-adherent dressing. If you have no ointment or dressing, you can leave the wound open.
• Clean and re-dress the wound twice a day.
• If the wound develops a crust, use wet-to-dry dressing changes. Put a dry sterile gauze pad over the wound and soak it with saline or a diluted antiseptic solution (such as 1% to 5% povidone-iodine in disinfected water). Allow it to dry then rip the bandage off the wound. The dead and dying tissue should adhere to the gauze and lift free. The tissue underneath should be pink and may bleed slightly but should be healing. Change the dressings once or twice a day. Use wet-to-dry dressings for a few days or until they become non-adherent. Then resume the regular wound dressing described above.
• Look for any signs of infection: extreme redness, red streaks on the extremity, pain, fever, pus or swollen lymph glands. If you have any, consult a qualified health professional about starting an antibiotic. A possible Vibrio bacteria infection can cause illness and even death in someone with an impaired immune system (e.g., from AIDS, diabetes or chronic liver disease).
• Watch for coral poisoning, which can occur if abrasions or cuts are extensive or from a particularly toxic species. Symptoms include a wound that heals poorly or continues to drain pus, swelling around the cut, swollen lymph glands, fever, chills and fatigue. If you have these symptoms, see a physician.

Complications

The most frequent complications from non-stinging coral scrapes are inflammation (which leads to poor healing) and less commonly a secondary infection. Proper wound cleaning is crucial. If fire coral is the culprit, then a diluted acetic acid solution, such as household white vinegar, is a reasonable topical decontaminant and should be used as a soak to reduce the pain. Immersion in hot water can reduce the symptoms. Hot water is ideal, but you can use instant hot packs, cold packs or ice packs. Provide symptomatic treatment for the inflammatory response. Steroid creams are rarely helpful, and they can prolong a skin infection. If the inflammation is severe, you may administer systemic steroids in a moderate, tapering dose under the supervision of a trained medical provider. Oral antihistamines can sometimes help reduce the itching or burning sensation. 

Possible Complications of an Old Problematic Wound

It is not uncommon for divers to contact DAN concerned about a minor skin abrasion on their hands, knees or elbows that happened months ago and has not healed despite proper care. These chronic wounds often have a red and bumpy appearance, occasionally develop a crust and are usually painless. If common antibiotic ointments do not help, divers wonder if the cause may be a marine-specific pathogen.

Divers with an open wound, even a small cut or scrape, are at risk for skin infections. When an old problematic wound fits the descriptions above, it might have become infected with an opportunistic pathogen known as Mycobacterium marinum. Despite the name there are no marine-specific pathogens that affect humans. Some infections are more common in aquatic environments. M. marinum is responsible for a condition commonly known as fish tank granuloma, or aquarium granuloma.

The red and bumpy nodules, no larger than a centimeter, are granulomas — inflammatory immune cells trying to wall off the pathogen. Granulomas are usually isolated but can sometimes appear in small clusters. They are not necessarily painful. There may or may not be discharge from the wound.

Characteristics of

M. marinum That Affect Healing

• The pathogen is opportunistic. It causes infection only in the right conditions (environmental and patient-related), so it is often not considered as a potential culprit.
• It likes cooler temperatures, which is why these wounds tend to flourish in areas with lower body temperatures such as hands, knuckles, elbows and knees.
• Only specific antibiotics work, so the typical antibiotic treatments are usually unsuccessful.
• The life cycle is slow, which means treatments last a long time. Sometimes patients will abandon what could have been a successful treatment or doctors may look for other potential explanations for the symptoms.
• It requires specific culture media that a doctor would not ask for unless they suspected this pathogen. Standard culture results are often negative, which delays the diagnosis.

Allow your doctor to examine the wound and follow their standard procedures. The doctor will probably ask you how it happened or when it started. Tell them about the superficial abrasion in a marine environment. You may want to ask specifically if M. marinum could be the cause. Your doctor does not need dive-specific medical knowledge for this type of issue.

Fitness to Dive

Always take care of wounds and clean them thoroughly no matter the severity. The skin is our most effective and efficient means of immunological defense. A compromised wound can get seriously infected.

As a rule, treat wounds properly and let them heal before diving. This is particularly important before traveling to a remote location or one with limited local medical care capabilities. A skin lesion with the potential for infection might warrant a more conservative decision to stay ashore if you have such a trip planned.

Chronic skin lesions require specific consultation with your physician team before diving. Your doctor may prescribe treatment or a protective covering to prevent skin breakdown.

The Chief Resident Presenting with a Coral Cut Injury: Infections…

CASE REPORT

By Marc A. Ciampi, MD,
and Andre N. Sofair, MD, MPH

A30-year-old previously healthy male pre-sented with pain in his left knee and left groin. Five days prior to presentation, he had scraped his exposed left knee against a large brain coral while snorkeling in the Caribbean, near the island of Aruba. He noted local erythema, slight pruritus, and a small abrasion. After irrigating the wound, the patient used topical antibacterial cream daily. He remained afebrile with no evidence of local or systemic complaints. He denied significant pain, increasing erythema, or wound drainage. On the day of presentation, the patient developed notable groin tenderness and mild left-sided lumbar pain along with increasing knee pain. He denied fever, chills, night sweats, or fatigue. He had no significant past medical history and was taking no medications. He had no known allergies and denied recent ingestion of shellfish.

The patient was afebrile with normal vital signs and general appearance. Physical examination of his knee was notable for the presence of a raised, slightly erythematous rash showing a dermatograph of brain coral, and a 2 mm abrasion with no significant drainage or fluctuance. The joint was normal with no evidence of effusion or inflammation. The left leg revealed tender inguinal lymphadenopathy without lymphangitis. Abdominal examination showed mild left upper quadrant and left costovertebral angle tenderness; a spleen tip was not palpated.

He was empirically started on an oral fluoroquinolone antibiotic, levofloxacin, to treat his soft tissue infection. Oral doxycycline was added one day later to ensure adequate coverage of various marine microorganisms. He was treated for 10 days with resolution of his groin tenderness and back pain after two days of therapy. Over three weeks, the rash resolved completely without complications.

Discussion

Contact with coral or “coral cuts” may produce significant and sometimes dramatic cutaneous reactions.^1,2 Manifestations include localized erythema, urticara, and occasional pruritus.³ The local reaction can be a response to coral nematocysts, contamination of the wound site with microparticulate coral and calcium carbonate, possible bacterial infection, or toxin effects.

Although on a worldwide basis staphylococci and streptococci remain the most common causes of soft tissue infections, vibrios, and some Aeromonas spp. are virulent waterborne organisms that may infect wounds sustained in a marine environment.^1-8Erysipelothrix rhusiopathiae, coliforms such as Escherichia coli, and Mycobacterium marinum, M. balnei, or Pseudomonas spp. are also capable of producing localized infections after exposure to salt water.⁶ Wound infections acquired in this environment may also be polymicrobial.^7,9

Ecology and Epidemiology

The halophilic Vibrio spp. are naturally free-living aerobic inhabitants of marine environments. These organisms have been found in Europe, Asia, Australia, South America, and North America.¹⁰ In North America, they have been recovered from the waters of the Gulf coast, the entire East Coast from Florida to Maine, the California and Washington State coasts, and from the waters around Hawaii. Halophilic vibrios have been found in both water and marine sediments, adherent to plankton, or absorbed onto mollusks and crustaceans. ¹¹Vibrio spp. are taken up by filter-feeding molluscs such as oysters, clams, mussels, and scallops achieving concentrations as high as 10⁶ bacteria per gram of oyster during periods of warm water temperatures. Bacteria are also found in the intestines of some estuarine fish, which may transport them between oyster beds or serve as a source of wound infections.¹²

Vibrio spp. reside in ocean water or marine estuaries within a wide range of salinity (1-34 parts per thousand). Organisms have been isolated from brackish lakes and even from the Great Salt Lake.¹³ A salinity greater than 25 parts per thousand has adverse effects on their survival.

Intolerant of cold conditions, Vibrio spp. thrive during the summer and fall months, but they may also survive the winter months in marine sediment.^5,14-18Vibrio spp. are found in zones where there is decreased dissolved oxygen concentrations, possibly reflecting increased nutrient concentrations in such areas. Vibrios are rarely found in the open ocean, likely due to colder water temperatures, the absence of nutrients, the higher hydrostatic pressures, and the relatively higher salinity.¹⁸

Vibrio infections are acquired either by the consumption of contaminated food and water or through skin and soft tissue injuries.⁴ The primary food sources for acquisition are raw/undercooked oysters or other seafoods.^4,19 In those with skin and soft-tissue infections, nearly all report prior recreational or occupational exposure to sea water or marine organisms.⁹

Clinical Presentations

Three major presenting clinical syndromes have been described for vibrios including gastroenteritis, soft tissue infection, and septicemia. There have been additional case reports of vibrio-associated otitis media, pneumonitis, keratitis, meningitis, and endometritis.^4,13

Soft tissue infections caused by noncholera vibrios may present as one of two distinct clinical entities, primary vibrio cellulitis, or secondary cellulitis following primary bacteremia. ⁴ Direct cutaneous inoculation from abrasions, lacerations, or puncture wounds may result in primary vibrio cellulitis. With the exception of V. cholerae O1, primary vibrio cellulitis has been associated with all known Vibrio spp.^1,5,20-23 In hospitalized patients with vibrio wound infections, the majority are caused by V. vulnificus (43%), followed by V. parahaemolyticus (29%) and V. alginolyticus (18%). The case fatality for V. vulnificus was 11%, and for V. parahaemolyticus it was 5%.⁹

Wound infections range from mild, limited disease to rapidly progressive, necrotizing infections.^9,10,13,19 Virulence may be related to the organisms’ capsular polysaccharide and lipopolysaccharide. Many vibrios also produce degradative toxins and enzymes. These include chitinases, which allow vibrios to colonize the exoskeletons of marine zooplankton, as well as hemolysins and metalloproteases, which break down tissues at the site of colonization. Vibrios also produce siderophores that scavenge iron from host transport proteins, transferrin and lactoferrin. This may account for the increased virulence of Vibrio spp. in patients with iron overload states.¹²

Cellulitis usually occurs within 24-48 hours but can occur as early as four hours, or as late as 12 days after exposure.^20,24,25 Fever occurs in 45-80% of primary cellulitis cases.⁴ Infected wounds are usually erythematous or ecchymotic, swollen and notably tender with little to no purulent discharge.^4,24 Vesicles or bullae with secondary necrotic centers and necrotizing fasciitis have also been described.^{9,12,16,24,26}

Patients with a history of liver disease, renal disease, chronic illness or immunodeficient states are at considerably increased risk of generalized sepsis following cellulitis.^{4,9,19,20,27-30} In cirrhosis, it has been suggested that porto-systemic shunting may allow vibrios to bypass the hepatic reticuloendothelial system. Additionally, liver disease predisposes such patients to complement deficiencies, impaired chemotaxis, and phagocytosis.³¹ Iron overload states also contribute to fulminant vibrio infection. Increased bioavailability of free iron, found in patients with hemochromatosis, may stimulate bacterial growth and metabolism. In addition, iron overload may impair normal host phagocytic activity, increasing susceptibility to infections.^12,31,32 Septicemia occurs in 15% of patients with primary soft tissue infections and contributes to the high case-fatality rates. In those with bacteremia, the rate is 32%; without hematogenous involvement, the case fatality rate is only 1%.⁹

Secondary cellulitis in the setting of primary septicemia associated with Vibrio spp. carries a 32-50% mortality rate.^4,9,10,19,33 In these cases, there is usually a preceding history of having eaten raw/undercooked oysters or other seafood ingestion.^4,19 These individuals develop generalized, metastatic, macular, or papular lesions in the setting of primary bacteremia. Culture-positive cutaneous lesions have been reported with bacteremia caused by V. vulnificus, V. cholerae non-O1, V. parahaemolyticus, and rarely V. alginolyticus.^4,34

Treatment of Coral-related
Soft Tissue Infection

Local wound care should include soap and water, followed by aggressive irrigation and debridement with saline solution and hydrogen peroxide to remove foreign material from the site and prevent secondary infection or granuloma formation.³⁵

Given the potential polymicrobial nature of coral-related infections, broad-spectrum antibiotics should be considered. For those with obvious cellulitis, or as a prophylactic measure in those with abnormal immune systems, antibiotics with a spectrum of activity against staphylococci and streptococci should be used. In addition, antibiotics that are effective against halophilic Vibrio spp. should be administered.

Vibrio spp. frequently produce beta-lactamases and are often resistant to various beta-lactam antibiotics. The beta-lactam inhibitor, sulbactam, does not completely render these organisms susceptible to ampicillin. They are often resistant to cephalothin, cefuroxime, and cefoperazone, but sensitive to cefotaxime, ceftazidime, aztreonam, and imipenem.

Although the fluoroquinolones, ofloxacin and norfloxacin, are effective against these organisms, ciprofloxacin appears to have the greatest activity with an MIC₉₀ of approximately 0.25 mg/L. Trimethoprim/sulfamethoxazole is effective, as are the tetracyclines and chloramphenicol.³⁶ For those with devitalized tissue or fasciitis, surgical intervention is indicated. This may be particularly important when dealing with infections caused by Vibrio damsela.^16,21,37 (Dr. Ciampi is a Clinical Instructor in Medicine at Yale University and Dr. Sofair is an Assistant Clinical Professor of Medicine at Yale University with the Emerging Pathogens Program, New Haven, Conn.)

References

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2. Brown CK, Shepherd SM. Marine trauma, envenomations, and intoxications. Emerg Med Clin North Am 1992;10:385-408.

3. Habif TP, Habie TP. A color guide to diagnosis and therapy. Clin Dermatol 1996;3:2005.

4. Blake PA, et al. Disease caused by a marine vibrio.
N Engl J Med 1979;300:1-5.

5. Morris JG, Black RE. Cholera and other vibrioses in the United States. N Engl J Med 1985;312:343-350.

6. Bateman JL, et al. Aeromonas hydrophilia cellulitis and wound infections caused by waterborne organisms. Heart Lung 1988;17:99-102.

7. Pien FD, et al. Bacterial flora of marine penetrating injuries. Diagn Microbiol Infect Dis 1983;1:229-232.

8. Kelly KA, et al. Spectrum of extraintestinal disease due to Aeromonas species in tropical Queensland, Australia. Clin Infect Dis 1993;16:574-579.

9. Hlady WG, Klontz KC. The epidemiology of vibrio
infections in Florida, 1981-1993. J Infect Dis 1996; 17:1176-1183.

10. Howard RJ, et al. Necrotizing soft-tissue infections caused by marine vibrios. Surgery 1985;98:126-130.

11. Limpert GH, Peacock JE Jr. Soft tissue infections due to noncholerae vibrios. Am Fam Physician 1988; 37:193-198.

12. Strom MS, Paranjpye RN. Epidemiology and pathogenesis of Vibrio vulnificus. Microbes and Infection 2000; 2:177-188.

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14. Oliver JD, et al. Distribution of Vibrio vulnificus and other lactose-fermenting vibrios in the marine environment. Appl Environ Microbiol 1983;45:985-998.

15. Linkous DA, Oliver JD. Pathogenesis of Vibrio vulnificus. FEMS Microbiol Lett 1999;174:207-214.

16. Yuen KY, et al. Fatal necrotizing fasciitis due to Vibrio damsela. Scand J Infect Dis 1993;25:659-661.

17. Penman AD, et al. Vibrio vulnificus wound infections from the Mississippi Gulf coastal waters: June to August 1993. South Med J 1995;88:531-533.

18. Joseph SW, et al. Vibrio parahaemolyticus and related halophilic vibrios. Crit Rev Microbiol 1982;10:77-124.

19. Klontz KC, et al. Syndromes of Vibrio vulnificus infections. Clinical and epidemiologic features in Florida cases, 1981-1987. Ann Intern Med 1988;109:318-323.

20. Howard RJ, Lieb S. Soft tissue infections caused by halophilic marine vibrios. Arch Surg 1988;123:
245-249.

21. Tang WM, Wong JW. Necrotizing fasciitis caused by Vibrio damsela. Orthopedics 1999;22:443-444.

22. Ien F, et al. Vibrio alginolyticus infections in Hawaii.
J Clin Microbiol 1977;5:670-672.

23. Porres JM, Fuchs LA. Isolation of Vibrio parahaemolyticus from a knee wound. Clin Orthop 1975; 106:245-247.

24. Johnston JM, et al. Vibrio vulnificus. Man and the sea. JAMA 1985;253:2850-2853.

25. Ho PL, et al. Necrotizing fasciitis due to Vibrio alginolyticus following an injury inflicted by a stingray. Scand J Infect Dis 1998;30:192-194.

26. Farina C, et al. Vibrio cholerae O₂ as a cause of a skin lesion in a tourist returning from Tunisia. Journal of Travel Medicine 2000;7:92-94.

27. Brennt CE, et al. Growth of Vibrio vulnificus in serum from alcoholics: Association with high transferrin iron saturation. J Infect Dis 1991;164:1030-1032.

28. Stabellini N. Fatal sepsis from Vibrio vulnificus in a hemodialyzed patient. Nephron 1998;78:221-224.

29. Ali A, et al. Vibrio vulnificus sepsis in solid organ transplantation: A medical nemesis. J Heart Lung Transplant 1995;14:598-600.

30. Ko WC, et al. Infections due to non-O1 Vibrio cholerae in southern Taiwan: Predominance in cirrhotic patients. Clin Infect Dis 1998;4:774-780.

31. Hor LI, et al. Survival of Vibrio vulnificus in whole blood from patients with chronic liver diseases: Association with phagocytosis by neutrophils and serum ferritin levels. J Infect Dis 1999;179:275-278.

32. Bullen JJ, et al. Hemochromatosis, iron and septicemia caused by Vibrio vulnificus. Arch Intern Med 1991; 151:1606 -1609.

33. Chuang YC, et al. Vibrio vulnificus infection in
Taiwan: Report of 28 cases and review of clinical manifestations and treatment. Clin Infect Dis 1992;15:
271-276.

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464-469.

35. Rosson Cl, Tolle SW. Management of marine stings and scrapes. West J Med 1989;150:97-100.

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37. Bia FJ. On damsels and distress from a vibrio species. Travel Medicine Advisor Update 2000;10:31-32.

Dolphins rub against corals and sponges to treat their skin

Indian bottlenose dolphins that live in the north of the Red Sea regularly rub against corals and sponges. Scientists have found that the mucus of these invertebrates contains biologically active substances, some of which have a negative effect on bacteria. Probably by contact with corals and sponges, dolphins prevent and treat skin infections with their secretions. The results of the study were published in an article for the journal iScience .

It is not easy for dolphins and whales to take care of their own skin, because their forelimbs have turned into flippers, and their hind limbs have completely disappeared. However, representatives of at least several species of these marine mammals have learned to cope with this problem. For example, killer whales ( Orcinus orca ) and beluga whales ( Delphinapterus leucas ) regularly rub against the sand and gravel at the bottom of the seas and river estuaries, peeling off the cornified layer of the skin and, probably, getting rid of skin infections and ectoparasites.

Indian bottlenose dolphins ( Tursiops aduncus ) from a Red Sea population around Hurghada and El Gouna (of approximately 360 individuals and long a focus of the Dolphin Watch research team) rubbing against soft corals Sar cophyton , horn corals Rumphella aggregata and sponges Ircinia . Often they even line up near the horn corals and sponges. At the same time, different types of invertebrates are used to treat different parts of the body. So, bottlenose dolphins rub their heads against sponges that are harder than corals. Similar behavior is demonstrated by dolphins that live off the coast of Florida and the Bahamas.

A team of zoologists led by Gertrud Morlock of the Justus Liebig University of Giessen suggested that bottlenose dolphins rubbing against corals and sponges not only cleanse the skin, but also fight skin infections. The fact is that many corals, including representatives of the genus Rumphella , produce mucus containing antimicrobial and cytotoxic compounds. By applying these secretions to their skin, dolphins could protect themselves from bacteria and fungi. In favor of this idea is the fact that bottlenose dolphins from the Red Sea sometimes pick off branches of horn corals and carry them in their mouths. From time to time, dolphins swing such branches, which stimulates the secretion of mucus, which settles on their heads in the form of yellowish and greenish spots.

To test the hypothesis, Morlock and her co-authors collected samples of corals and sponges that bottlenose dolphins from the Red Sea rub against. They carried out a chemical analysis of the mucus secreted by these invertebrates and also assessed its antimicrobial potential using bacteria Aliivibrio fischeri and Bacillus subtilis as examples. It turned out that the secretions of all three genera contain biologically active metabolites. In total, the scientists counted seventeen compounds with antimicrobial, antioxidant, or hormone-like properties. At the same time, the metabolites of horn and soft corals are more similar to each other than to sponge metabolites.

The results of the study confirm that Indian bottlenose dolphins use coral and sponge secretions for treatment. Primarily, this behavior helps prevent and treat bacterial skin infections, and may also help maintain skin health in other ways. The authors note that this is the first example of cetaceans self-medicating with secondary metabolites from other species. It is assumed that dolphins can use such compounds for other purposes. For example, Australian bottlenose dolphins ( T. a. australis ) catch and play with pufferfish, possibly for their poison, which gives a feeling of numbness or even an intoxicating effect.

Earlier, we talked about how Amazonian dolphins ( Inia geoffrensis ) from a Bolivian river played with an anaconda ( Eunectes beniensis ) in front of zoologists. Two adult males swam synchronously, raising their heads above the water, one holding the snake by the neck, and the other by the front third of the body. From time to time, they seemed to demonstrate the reptile to teenage dolphins who were there. At the same time, the anaconda itself died during the game.

Sergey Kolenov

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Dolphins line up for self-treatment of skin diseases in coral “clinics”

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If a person gets sick with a rash, he can go to the doctor and he will prescribe an ointment or tablets for him to treat it. Indo-Pacific bottlenose dolphins (a type of dolphin) also get skin diseases and are kind of like people lining up nose-to-tail at the clinic to rub themselves against corals.

New research shows these corals have medicinal properties, suggesting dolphins use marine invertebrates to treat skin conditions, eurekalert.org reports.

Thirteen years ago, co-author Angela Siltener, a wildlife biologist at the University of Zurich, Switzerland, first observed dolphins rubbing against corals in the northern Red Sea, off the coast of Egypt. She and her team noticed that the dolphins were selective about which corals they rub against, and they wanted to understand why. “I hadn’t seen the coral friction behavior described before, and it was clear that the dolphins knew exactly what kind of coral they wanted to use,” Ziltener says. “I thought, ‘There must be a reason.

Most dolphin research is done from the surface of the water, but because Siltener is a diver, she was able to study dolphins up close.

She and her colleagues were able to identify and sample the coral that the dolphins were rubbing against. The researchers found that repeated rubbing of dolphins against coral stimulated the tiny polyps that make up the coral community, and these invertebrates secreted mucus.

In order to understand what properties the slime contained, the team collected samples of these corals.

Using various surface analysis methods and adding high resolution mass spectrometry to analyze samples of gorgonian coral Rumphella aggregata, skin coral Sarcophyton sp. and the sponge Ircinia sp., they found 17 active metabolites with antibacterial, antioxidant, hormonal, and toxic activity.

This discovery of these biologically active compounds convinced the team that coral and sponge mucus serves to regulate the dolphin’s skin microbiome and treat infections.