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-related injuries. How to identify and treat complications from coral skin infections.

The Nature of Coral Skin Infections: More Than Meets the Eye

Coral skin infections are a prevalent concern among divers and snorkelers, with the Divers Alert Network (DAN) receiving approximately one inquiry per week related to coral contact incidents. These injuries, often underestimated, can be more complex than typical outdoor scrapes and cuts. Why? The answer lies in the unique composition of coral and its marine environment.

Coral is not just a static, rocky formation. It’s a living ecosystem covered with soft tissues that harbor various organisms and potential toxins. When a diver or snorkeler comes into contact with coral, especially the sharp-edged stony corals, the risk of injury goes beyond a simple scrape. The soft tissue can tear easily, introducing foreign material into the wound and triggering a cascade of inflammatory responses.

What makes coral cuts different from regular scrapes?

• Presence of living marine organisms on the coral surface
• Potential introduction of toxins and antigens into the wound
• Prolonged healing time due to foreign material in the cut
• Risk of granuloma formation from debris retention

Understanding these factors is crucial for proper treatment and prevention of complications. Let’s delve deeper into the mechanisms of injury and the manifestations of coral skin infections.

Mechanisms of Injury: The Hidden Dangers of Coral Contact

When we think of coral, we often picture beautiful, colorful structures beneath the sea. However, these structures can pose significant risks to human skin upon contact. The mechanism of injury from coral is multifaceted and can lead to complex wound healing processes.

How does coral cause skin injuries?

1. Abrasion from rigid coral structures
2. Tearing of soft coral tissues
3. Introduction of foreign material into the wound
4. Potential envenomation from certain coral species

The rigid structure underneath the soft living tissues of stony corals acts like sandpaper against human skin. When contact occurs, not only does it scrape the skin, but it can also tear the coral’s soft tissue, introducing various substances into the wound. This foreign material can include coral fragments, microorganisms, and even toxins, depending on the coral species.

In the case of hydroids like fire coral, the mechanism of injury includes envenomation. These organisms contain nematocysts – microscopic stinging cells that can inject venom upon contact. Even a simple brush against fire coral can trigger these cells, leading to more severe reactions than a typical scrape.

Manifestations of Coral Skin Infections: Recognizing the Signs

Coral skin infections can manifest in various ways, depending on several factors. The extent of the reaction is influenced by the presence and amount of toxins, the size and location of the abrasion, and the individual’s pre-existing sensitivity to marine organisms.

What are the common symptoms of coral skin infections?

• Burning sensation
• Pain
• Itching
• Rash (especially with hydroid contact)
• Blistering (in case of fire coral)

The initial symptoms often include a burning sensation accompanied by pain and itching. In cases involving hydroids like fire coral, a rash may develop. Fire coral contact typically results in blistering, which usually appears a few hours after the incident.

It’s important to note that coral skin infections can have a latent evolution. Symptoms may persist or even worsen weeks or months after the initial injury, often confusing both patients and healthcare providers. This delayed reaction is particularly common with hydroid envenomations, where apparent healing may be followed by a relapse within a week or two.

Prevention Strategies: Minimizing the Risk of Coral Injuries

While coral skin infections can be troublesome, they are largely preventable with proper precautions. Divers and snorkelers can significantly reduce their risk of injury by following some key preventive measures.

How can divers and snorkelers prevent coral injuries?

• Avoid contact with coral and other marine life
• Wear protective clothing such as wetsuits or dive skins
• Maintain proper buoyancy control
• Be aware of currents that might push you into coral
• Carry a marine animal first aid kit

The primary rule is to avoid contact with coral or any other living creature underwater. This not only protects the diver but also helps preserve delicate marine ecosystems. Wearing a wetsuit or dive skin provides an extra layer of protection in case of accidental contact, especially in situations where currents or other divers might inadvertently push you into coral.

For ocean divers, carrying a marine animal first aid kit is highly recommended. Having the necessary supplies on hand can significantly reduce the time to proper first aid administration, potentially minimizing the severity of injuries.

Additionally, educating oneself about marine life through identification courses, first aid training, and relevant literature can enhance awareness and preparedness. This knowledge can be crucial in recognizing potential hazards and responding appropriately to injuries.

First Aid for Coral Injuries: Immediate and Effective Care

Proper first aid is crucial in managing coral skin infections and preventing complications. The goal is to clean the wound thoroughly, prevent infection, and promote healing. Here’s a step-by-step guide to providing effective first aid for coral injuries:

What are the essential steps in treating coral cuts and scrapes?

1. Cleanse the wound vigorously with soap and water
2. Flush with a diluted hydrogen peroxide solution
3. Apply antiseptic ointment and cover with a sterile dressing
4. Clean and re-dress the wound twice daily
5. Use wet-to-dry dressings for crusted wounds
6. Monitor for signs of infection
7. Watch for symptoms of coral poisoning

Begin by scrubbing the cut vigorously with soap and water, then flush it with copious amounts of clean water. Follow this with a rinse using a half-strength solution of hydrogen peroxide in water, and then rinse again with clean water.

Apply a thin layer of antiseptic ointment and cover the wound with a dry, sterile, non-adherent dressing. If these supplies are unavailable, leaving the wound open is acceptable. It’s crucial to clean and re-dress the wound twice a day to prevent infection and promote healing.

For wounds that develop a crust, employ wet-to-dry dressing changes. This involves applying a saline or diluted antiseptic-soaked gauze pad to the wound, allowing it to dry, then removing it to lift off dead and dying tissue. This process should be repeated once or twice daily until the dressings become non-adherent.

Recognizing and Managing Complications

While many coral injuries heal without incident, complications can occur. Being able to recognize the signs of infection or coral poisoning is crucial for timely intervention and proper treatment.

What are the warning signs of complications from coral injuries?

• Extreme redness or red streaks on the extremity
• Increased pain or fever
• Presence of pus
• Swollen lymph glands
• Poorly healing or continuously draining wound
• Swelling around the cut
• Chills and fatigue

If any of these signs appear, it’s essential to consult a healthcare professional promptly. There’s a risk of Vibrio bacteria infection, which can be particularly dangerous for individuals with compromised immune systems, such as those with AIDS, diabetes, or chronic liver disease.

Coral poisoning is another potential complication, especially if the abrasions are extensive or from a particularly toxic species. Symptoms include poor wound healing, persistent pus drainage, swelling around the cut, swollen lymph glands, fever, chills, and fatigue. If these symptoms develop, immediate medical attention is necessary.

Long-Term Care and Healing Process

The healing process for coral skin infections can be protracted, often taking weeks or even months. This extended timeline can be frustrating for patients and challenging for healthcare providers. Understanding the factors that influence healing can help manage expectations and guide appropriate care.

Why do coral injuries often take longer to heal?

• Presence of foreign material in the wound
• Ongoing inflammatory response
• Potential for granuloma formation
• Individual variations in immune response
• Environmental factors (e.g., humidity, water exposure)

The presence of coral fragments, microorganisms, or toxins in the wound can prolong the inflammatory process, delaying healing. In some cases, the body’s attempt to eliminate foreign material can lead to the formation of granulomas – small, raised, tender bumps that may persist for some time.

Environmental factors also play a role in the healing process. Humidity and frequent water exposure, common in tropical diving locations, can affect wound healing. It’s important to keep the wound clean and dry as much as possible during the healing process.

Patience and consistent care are key in managing coral skin infections. Regular wound cleaning, appropriate dressing changes, and monitoring for signs of complications are essential throughout the healing process. In cases of persistent symptoms or delayed healing, consultation with a dermatologist or a physician experienced in tropical medicine may be beneficial.

Ecological Considerations and Responsible Diving

While discussing coral skin infections, it’s crucial to address the broader context of coral reef health and the role of responsible diving practices. Coral reefs are delicate ecosystems facing numerous threats, and diver behavior can have significant impacts.

How can divers contribute to coral reef conservation?

• Practice perfect buoyancy control
• Avoid touching or standing on coral
• Use reef-safe sunscreen
• Participate in reef clean-up activities
• Support marine protected areas
• Educate others about coral reef conservation

Mastering buoyancy control is perhaps the most crucial skill for reef conservation. It allows divers to navigate coral environments without accidentally touching or damaging coral structures. Additionally, using reef-safe sunscreen products helps prevent harmful chemicals from affecting coral health.

Many dive operators and conservation organizations offer opportunities to participate in reef clean-up activities. These initiatives not only help remove harmful debris from coral ecosystems but also raise awareness about marine conservation issues.

By adopting and promoting responsible diving practices, divers can play a significant role in preserving coral reefs for future generations while also minimizing their own risk of coral-related injuries.

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.

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

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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.

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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.

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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.