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Black Banded Sea Krait Bite

Last updated March 23, 2019

Approved by: Krish Tangella MD, MBA, FCAP

Daiju Azuma

The black banded sea krait (Laticauda semifasciata) is a highly venomous sea snake that is found predominantly along seashores and coastal areas in China Sea and western Pacific Ocean.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Chinese Sea Krait Bite
  • Erabu Sea Krait Bite
  • Laticauda Semifasciata Snake Bite

What is Black Banded Sea Krait Bite? (Definition/Background Information)

  • The black banded sea krait (Laticauda semifasciata) is a highly venomous sea snake that is found predominantly along seashores and coastal areas in China Sea and western Pacific Ocean
  • It belongs to the group of banded sea kraits of family Elapidae, which generally includes slender and swift moving snakes. The black banded sea krait is also known as the Chinese sea krait or Erabu sea krait in Japan. It is regularly harvested for its meat and skin in some regions of China and Japan
  • The snake is characterized by a short head and neck (black in color), smooth round silver white body, light-colored or whitish upper lip, black bands placed uniformly along its length, and a paddle-like flat tail to help it swim. The bands may not be very distinct, may be brown in color, or even appear as partial bands in older snakes (fading with age), giving the snake the name half-banded sea krait
  • Even though semi-aquatic in nature, unlike other sea kraits, the black banded sea krait spends less of its time on land. Sea snakes do not have gills, unlike fish, and hence must surface to breathe. But, nevertheless, this sea krait can stay up to 6 hours underwater before surfacing
  • A fully-grown adult black banded sea krait can reach about 3 feet in length; usually, females are much larger and heavier than males (from 4.5 to 6 feet in size). The snake feeds on fish and other marine creatures. This marine reptile hunts in shallow waters and among coral reefs during the night; but it comes to land for safety from predators, to digest food, shed its skin, and to mate
  • Mostly, it is the fishing and coastal-dwelling communities in the tropical endemic regions, which come into contact with the sea snake. The black banded sea krait is a gentle, non-aggressive snake that avoids humans. It is typically reluctant to bite, even when picked or handled
  • This sea snake has tiny fangs and its bite may go unnoticed; the bites are also quite painless or produce minimal pain. Nonetheless, the Black Banded Sea Krait Bite can cause life-threatening to fatal envenomation (venom injection), without prompt and adequate treatment
  • The signs and symptoms of Black-Banded Sea Krait Bite may be apparent within a few hours following a bite. The snake venom is a highly potent mix of myotoxin and neurotoxin, which can cause systemic symptoms such as muscle weakness and breakdown, seizures, respiratory failure, and severe paralysis
  • Early administration of suitable antivenom (or antivenin) is the mainstay of treatment. Apart from this, symptomatic treatment is necessary, which may include pain medication, hydration, and respiratory support. The prognosis of Black Banded Sea Krait Bite with immediate and effective therapy is usually good

Who gets Black Banded Sea Krait Bite? (Age and Sex Distribution)

  • Black Banded Sea Krait Bite may occur to any individual exposed to the snake, usually in the coastal areas or while at sea (when fishing or diving)
  • Individuals of any age and gender are prone to sea snake bites in the endemic zones
  • The black banded sea krait is mostly found in East Asia and parts of western Pacific Ocean. The countries where the reptile is reported from include:
    • Parts of China (South China Sea) and Taiwan
    • Japan and South Korea
    • Southeast Asian nations of Indonesia, Philippines, Singapore, and parts of Malay peninsula
    • Island nations in the Pacific Ocean including Fiji and Samoa

What are the Risk Factors for Black Banded Sea Krait Bite? (Predisposing Factors)

The risks for Black Banded Sea Krait Bite include the following factors:

  • Living or residing in the coastal regions endemic to the snake
  • Occupational hazard: Fishermen and fisherwomen, while sorting fish, setting out fishing nets, pulling in the ‘catch’
  • Some snakes are found in fishing or trawling boats, hiding in the exhaust pipes and other nooks and corners of the vessels
  • Sea snake catchers, who hunt the snake for skin/leather (particularly in some parts of China). The snake is also commonly caught for its meat in parts of China and Japan
  • Swimmers, surfers, coral reef divers, and beachgoers; the snake is often found in groups in tree roots, near rocky shores, small islands/islets, and coral reef or sandy beaches
  • Among the coastal community residing by the seaside - venturing outdoors during the night such as for toilet
  • Marine life enthusiasts and scientific study groups, who explore the region
  • Wading in ocean waters without suitable protective clothing
  • Walking barefoot on the beach or in shallow sea waters
  • Keeping them as pets in aquariums (exotic collection)
  • Handling dead or live snakes; intentionally or accidentally picking up the snake

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Black Banded Sea Krait Bite? (Etiology)

Black Banded Sea Krait Bite can take place when one comes into contact with the venomous sea snake, usually unintentionally or inadvertently.

  • The sea snake is unusually docile and does not commonly bite. Individuals, who come into contact with the snake, are often bitten only under self defense when sufficiently provoked
  • The black banded sea krait venom is strongly neurotoxic that can cause paralysis and death. The venom can also cause muscle tissue breakdown, since it is myotoxic too
  • The severity of the signs and symptoms depend on factors such as the location of the bite, age and health of the individual, and amount of venom injected

According to some scientific literature, the black banded sea krait venom is much more (up to 10-times more) potent than the venom of a cobra.

What are the Signs and Symptoms of Black Banded Sea Krait Bite?

The signs and symptoms of snake bites depend on the age (whether child or adult), body weight, and overall health status of the individual (whether having an underlying condition or illness). Also, the signs and symptoms vary according to the potency and amount of venom injected.

The signs and symptoms of Black Banded Sea Krait Bite can vary from one individual to another. It may develop within a few hours and include:

  • Bite or fang marks on arm or leg; there may be no pain or negligible pain and swelling at the bite site
  • Nausea, vomiting, and diarrhea
  • Abdominal pain
  • Headaches
  • Body aches and muscle aches
  • Poor reflexes
  • Pain, fatigue, and weak muscles
  • Enlarged lymph nodes
  • Anxiety, drowsiness, and confusion
  • Blurred vision
  • Breathing difficulties; labored breathing
  • Feeling faint or dizzy
  • Convulsions
  • Blue-colored skin due to poisoning
  • Weakness and malaise
  • Unconsciousness

Systemic signs and symptoms may include:

  • Muscle damage; progressive muscle weakness
  • Difficulty speaking and swallowing
  • Individuals may be unable to stand, sit, or even raise their arms and legs
  • Neurological symptoms including moderate to severe paralysis
  • Kidney injury causing acute kidney failure is reported


  • In some cases, the fang marks may not be pronounced or even visible. Sometimes, only small scratch marks or lacerations may be observed. Thus, any contact with a sea snake merits immediate medical attention
  • Severe anxiety may also result in some misleading symptoms of snakebites, such as sweating, fatigue, and shock, even when no bite has taken place (the individual may be imagining), or when it is a dry bite. Nevertheless, even in suspect cases, the presence of any such symptoms requires the attention of a qualified medical professional
  • Also, if the individual has been treated using alternative/native medicines, it may present additional confusing symptoms. Thus, it is important to always consult a qualified healthcare provider promptly

How is Black Banded Sea Krait Bite Diagnosed?

Black Banded Sea Krait Bite may be diagnosed using the following tests and exams:

  • Complete physical examination with comprehensive evaluation of medical history; a physical examination of the affected site by the physician may be normally sufficient to diagnose a snake bite
  • The individual may be asked to provide an account (history) of the events that occurred (what took place and how), if possible
  • Assessment of the signs and symptoms exhibited by the individual may be carefully observed
  • Blood tests that may include:
    • Complete blood count (CBC) with differential and platelet count
    • White blood cell count
    • Creatine kinase blood test
    • Lactate dehydrogenase (LDH) test
    • Serum electrolytes including blood urea nitrogen (BUN) and creatinine levels
    • Aspartate transaminase blood test
  • Urine test or urinalysis to test for free protein, myoglobin, and hemoglobin levels
  • Electrocardiogram (ECG)
  • Nerve conduction studies and neurological evaluation

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Black Banded Sea Krait Bite?

The complications of Black Banded Sea Krait Bite may include:

  • Breakdown of  muscle tissue or myolysis; this may take place rapidly
  • Tissue and muscle damage, which can result in superimposed infections
  • Flaccid paralysis that is severe; the onset of paralysis may occur within a few hours following the sea snake bite
  • Loss of respiratory function due to neurological symptoms, which can be fatal
  • Acute kidney failure
  • Coma

Presence of misleading symptoms due to fear and anxiety, which may be also aggravated by those around the individual, such as one’s family members, can sometimes result in inappropriate or over-treatment.

Antivenom reactions:

  • Some individuals may develop an allergic reaction, such as anaphylaxis, to the antivenom that may be serious. This may develop within 10 minutes or even after 6 hours, typically starting with itchiness over the scalp and other skin areas
  • Life-threatening anaphylactic reactions that require immediate medical treatment may include:
    • Low blood pressure or hypotension
    • Bronchospasm causing narrowing of the airways (bronchi) resulting in breathing difficulties
    • Angioedema: Swelling of skin tissue layers at various locations including the throat, causing speaking and breathing difficulties
  • Serum sickness may develop as a complication of antivenom therapy causing fever, nausea, itchy skin, muscle and joint pain, etc. It may develop after 4 days or even 2 weeks (average 7 days) following the administration of antivenom serum

How is Black Banded Sea Krait Bite Treated?

All sea snake bites should be considered as medical emergencies and evaluated by trained medical professionals, as soon as possible; the first 6-8 hours are particularly vital for preventing life-threatening symptoms. Failure to obtain early assessment and management from the highest level of care (available within the community) may potentially result in severe complications and death.

The following measures may be considered in the treatment of Black Banded Sea Krait Bite, based on the medical evaluation of a trained healthcare professional. The snake bite can cause severe envenomation and hospitalization is generally necessary. In many cases, urgent first aid care and support, in the form of compression bandages, limb immobilization, and monitoring of vital signs is necessary and highly-recommended before the patient is hospitalized.

  • Administration of sea snake antivenom, to neutralize the venom through slow intravenous injection or infusion method
  • Address any signs or early allergic reaction: A close observation of the patient is necessary for a minimum of 60 minutes immediately following antivenom administration, to detect early allergic reactions, if any
  • Administration of intravenous fluids to keep the patient well-hydrated:
    • Good hydration is important, since potential myolysis (muscle breakdown) can cause severe failure of kidney function
    • Adequate hydration helps in decreasing the risk for kidney damage due to myolysis; hence, continuous measurement of urine output (day and night) is important
  • Periodic blood and urine tests are undertaken for 12-24 hours or more
  • Intubation and respiratory support is usually necessary
  • Tetanus vaccination is usually required, if it is not up to date
  • The patient is admitted and placed in an ICU setting and monitored for at least a day following the abatement of symptoms; the patient has to be rested and kept warm
  • Administration of pain medication, if needed
  • If necessary, blood and plasma transfusions for severe cases
  • Medications to control blood pressure
  • Peritoneal dialysis for acute kidney failure, if required
  • Providing life support, such as ventilation assistance and treatment for shock, for those with severe symptoms leading to potential organ failure
  • Rehabilitation of the affected limb through physical therapy, if required
  • Unless infection or tissue necrosis is observed, the administration of prophylactic antibiotics is generally not recommended in snake bites. However, the healthcare provider will determine whether antibiotics administration is necessary or not, based on one’s individual circumstances


  • Consultation with a medical toxicologist is recommended for all cases requiring the administration of anti-snake venom
  • Even though antivenom therapy is the key treatment for systemic envenomation; on its own, it may never be adequate enough to completely resolve the condition. Other supportive and symptomatic measures are always necessary to save the patient
  • The dose of antivenom does not vary for a child, adult, or even for a pregnant woman, since the snake typically injects the same quantity of venom into an individual
  • Gynecological evaluation may be necessary for pregnant women bitten by sea snakes to evaluate the health of the fetus
  • In many instances, the type of venomous snake involved in the bite is unknown; hence, all vital organs and systems should be closely monitored and treated appropriately, as necessary

How can Black Banded Sea Krait Bite be Prevented?

Black Banded Sea Krait Bite may be avoided by:

  • Completely avoid any sort of water or sea snake, especially in the endemic zones
  • Educating fishing community about sea snakes and the techniques for handling them, untangling them from fishing nets, etc. Fishermen are at risk of being bitten by sea snakes while sorting the catch from the net, since in many cases the head and tail of sea snakes are quite indistinguishable
  • Ensure that employers provide adequate protective clothing (gloves, boots, etc.) to those who work in high-risk (for snake bite) occupations such as agriculture or fishing industry
  • Do not ignore warnings of lifeguards or health officials at the beach
  • Wear protective clothing if you plan to swim or dive in infested areas (suitable wet skin or diver’s suit)
  • Generally be aware or watchful of the waters you are in (to the extent possible)
  • Be on the alert while cleaning or repairing boats and trawlers, since the snake is sometimes known to hide in them
  • Wear protective footwear while walking on beach sand
  • Ensure safety precautions while cleaning marine animal aquariums; wear gloves
  • Marine life explorers and sea adventurers are required to carry marine first aid kit
  • If you spot a sea snake (on land), step back slowly and keep a safe distance between yourself and the snake
  • Be on the lookout for snakes and other animals while outdoors (especially while exploring small islands and rocky beaches); also, if you are with a pet, do not allow the pet to wander away
  • Always allow snakes crossing your path the right of way
  • Be alert, if you are in snake-infested regions, particularly containing dangerous species of snakes
  • Avoid picking up firewood sticks, stones, or rocks without checking the area for any concealed creatures
  • Near coastal areas, always check before sitting on dead tree logs, stumps, or a pile of rocks; use a stick to stir or probe around the area
  • Avoiding being on beaches at night; be careful while camping outdoors by seaside
  • Avoid playing with or teasing snakes such as by touching their tails
  • Do not pick up dead snakes - they may be poisonous and still bite through a reflex action
  • Do not reach into dark nooks/corners/recesses with your bare hands/foot
  • Teach and educate children about the dangers and importance of snakes
  • Take steps to educate the members of a community to identify venomous snakes, recognize bite symptoms, and how to avoid encounter with snakes

Both large and small snakes have the potential for severe envenomation; hence, all snake bites should be treated promptly and appropriately.

Also, in case of a snake bite, do visit a registered medical practitioner immediately (and not any native or traditional medicine experts).

What is the Prognosis of Black Banded Sea Krait Bite? (Outcomes/Resolutions)

  • The prognosis of Black Banded Sea Krait Bite is dependent on the site of bite, age and overall health of the individual, promptness of medical response, and continued observance and treatment of complications following admission of the patient. However, the overall prognosis is primarily based on the quickness with which suitable antivenom is administered
  • Without treatment or access to proper healthcare, deaths from severe complications, such as respiratory distress, severe paralysis, and heart failure are reported

Additional and Relevant Useful Information for Black Banded Sea Krait Bite:

  • The black-banded sea krait is sometimes mistaken for the blue-banded sea krait and the terminologies are used interchangeably. However, scientifically the former is known as Laticauda semifasciata and the latter Laticauda laticaudata. Also, L. semifasciata is much more venomous than L. laticaudata
  • In some areas of Japan, a soup made from the black-banded sea krait is believed to have medicinal properties, from ancient times
  • In some cases, the snake bite may be a ‘dry bite’, meaning that even though there is a bite mark, no venom injection occurs. However, even for dry bites, the patient must be placed under observation and monitored closely for a period ranging anywhere from 12-24 hours, prior to discharge

Depending on the geographical region, either monovalent antivenom or polyvalent antivenom may be administered for systemic envenomation. Monovalent antivenom neutralizes venom of a single snake species only, whereas polyvalent antivenom can neutralize the venom of several snake species.

The snake venom is a highly complex mix of several proteins, enzymes, amino acids, peptide chains, fats, and even certain metals. The bite causing venom injection into the body may be categorized as:

  • Intramuscular injection: Long-fanged snakes have a potential for injecting venom directly into the muscles (this is highly infrequent though)
  • Intraperitoneal injection: When the snake bite involves the stomach or abdomen region
  • Intravenous injection: In very rare cases, the snake fangs may inject venom directly into a blood vessel, releasing venom directly into blood (posing an even greater danger than normal snake bites)
  • Subcutaneous injection: A majority of snake bites involve the subcutaneous skin layers (venom is injected just below the skin surface)

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: March 23, 2019
Last updated: March 23, 2019