Can Sharks Get Sick or Contract Diseases?

Sharks have long been one of the most feared and mysterious creatures of the sea. With their powerful jaws, sharp teeth, and mysterious behaviors, it is no wonder that they have become an object of human fascination. 4

But what many people don’t realize is that sharks are just as vulnerable to diseases and illnesses as any other species.

In this article, we will discuss can sharks get sick or contract diseases and explore some of the ways that they may do so.

Can Sharks Get Sick
Image: Sharks get sick

Shark Immune System

Sharks have a robust immune system that helps them fight off diseases and infections. They have a unique immune system that is different from other fish and mammals, which allows them to quickly detect and eliminate pathogens.

Sharks have a high concentration of leukocytes, or white blood cells, in their blood which play a key role in their immune response. They also have a type of lymphocyte called a “natural killer cell” that can recognize and target infected or cancerous cells.

Additionally, sharks have a set of antibodies that are more effective at neutralizing viruses than the antibodies found in other animals. These unique features of sharks immune system make them less susceptible to common diseases and infections.

Can Sharks Get Sick or Contract Diseases

Sharks have a better chance of resisting diseases than humans because they have a system in their body that helps them fight infections.

Sharks also have a slower metabolism, which means that they can hold off on eating for longer periods of time, which can help them avoid getting sick.

There are a variety of diseases and conditions that can affect sharks. Some examples include:

Bacterial infections

Sharks, like all animals, can be affected by bacterial infections. Bacteria are tiny microorganisms that can cause a range of diseases and infections in animals, including sharks.

Bacterial infections in sharks can cause a variety of symptoms, depending on the specific type of bacteria and the area of the body affected.

Some common symptoms of bacterial infections in sharks include:

Skin lesions

Sharks can develop skin lesions or abscesses due to bacterial infections. These can be visible as raised bumps or patches of damaged or infected skin.


Septicemia, also known as blood poisoning, is a serious condition that can occur when bacteria enter the bloodstream and multiply.

Respiratory infections

Sharks can also develop respiratory infections due to bacterial infections, which can cause symptoms such as difficulty breathing, coughing, and sneezing.

Bacterial infections in sharks can be treated with antibiotics, but the specific treatment will depend on the type of bacteria and the severity of the infection.

It is important to diagnose and treat bacterial infections in sharks as soon as possible to prevent the spread of the infection and to ensure the best possible outcome for the animal.

Viral infections

Sharks can be affected by viral infections. These infections can cause a wide range of symptoms, depending on the specific virus and the shark species.

Some common symptoms of viral infections in sharks may include abnormal growths or lesions on the skin, changes in skin color, changes in the texture or appearance of the fins or gills, abnormal behavior or appetite, and difficulty swimming or breathing.

Fungal infection

Fungal infections can affect sharks, just like they can affect other animals and humans.

Fungal infection activated by warm temperatures, which further manifests in the form of ulcers.

Sharks can be caused by a variety of fungi, including yeasts and molds. These infections can affect the skin, fins, gills, and other tissues of sharks.

Symptoms of fungal infections in sharks may include abnormal growths or lesions on the skin, changes in skin color, changes in the texture or appearance of the fins or gills, and abnormal behavior or appetite.

Fungal infections can be serious and potentially life-threatening for sharks, especially if left untreated.


Sharks can be infected by a variety of parasites, including tapeworms and other types of worms, protozoans, and ectoparasites.

These parasites can infect different parts of the shark’s body, including the brain, eyes, gills, and other organs, and can have a range of impacts on the health and survival of the shark.

In some cases, infections with certain types of parasites can be severe and even life-threatening.

There are many examples of parasites that can infect sharks, and some of these parasites can cause significant mortality in certain shark populations.

For example, the “zombie” parasite, which is believed to have caused the deaths of thousands of leopard sharks in the San Francisco Bay in 2017 is a species of flatworm called Polyodon spathula. This parasite infects the nasal passages of the shark and can eventually cause brain damage and death.

Why Do Sharks Don’t Get Sick?

Sharks do get sick, but they seem to have a higher resistance to diseases compared to other animals. There are some possible reasons discuss below:

Sharks have a unique immune system

Sharks have a unique immune system that is different from that of other animals. For example, they have a high concentration of leukocytes (white blood cells) that help protect against infections.

Sharks have a high tolerance for toxins

Sharks have a high tolerance for toxins, which may help protect them against certain diseases. For example, some sharks can tolerate high levels of mercury, which can be toxic to other animals.

Sharks have a slow metabolism

Sharks have a slow metabolism, which may help protect them against certain diseases. For example, a slow metabolism may help prevent the buildup of harmful substances in the body.

Sharks have a high regeneration ability

Sharks have a high ability to regenerate their tissues, which may help protect them against certain diseases. For example, some sharks can regrow their fins if they are damaged.

While sharks may have some inherent disease-protective mechanisms, it is important to recognize that disease is a complex phenomenon with many different causes and risk factors.


Can Sharks Get Tumors?

Tumors, also known as neoplasms, are abnormal growths of cells that can occur in any species, including sharks. Tumors can be benign (non-cancerous) or malignant (cancerous). Cancerous tumors were found on sharks in 1908.

Benign tumors do not spread to other parts of the body and are generally not life-threatening, while malignant tumors can spread to other parts of the body and can be life-threatening.

While sharks may have a lower incidence of cancer compared to other animals, there have been a few isolated cases of cancer in sharks.

Do sharks have immunity to cancer?

Sharks are known for their ability to heal quickly from wounds and injuries, there is no scientific evidence to support the claim that they have a greater resistance to cancer or that their immune systems are specifically adapted to protect against cancer.

While it is possible that some species of sharks may have immune system features that allow them to repair damaged tissue more effectively, this does not necessarily mean that they are less likely to develop cancer or that they are immune to the disease.

Can humans get sick from sharks?

While it is possible for humans to get sick from sharks, this is generally not a common occurrence. Most shark species do not pose a significant risk of disease transmission to humans.

However, some species of sharks and other marine animals, including certain types of rays and fish, can carry bacteria that can cause infections in humans.

These infections can occur if a person is bitten or scratched by a marine animal, or if the person comes into contact with the animal’s bodily fluids or tissues.

How do sharks protect themselves from bacteria and virus?

Sharks do have some unique characteristics that may contribute to their ability to resist certain types of infections.

For example, sharks have been found to produce small, flexible antibodies that may be more effective at neutralizing certain viruses (Rich).

In addition, sharks have a high concentration of compounds called antimicrobial peptides in their skin, which may help to protect against bacterial infections.


  • A Class of Shark‐Derived Single‐Domain Antibodies can Broadly Neutralize SARS‐Related Coronaviruses and the Structural Basis of Neutralization and Omicron Escape.” NCBI, 18 May 2022.
  • Rakshit, Devrupa et al. “Scientists Believe A Mysterious Skin Disease In Reef Sharks Is Due To Climate Change”. The Swaddle, 2021.
  • Rich, Gina. “Studying sharks’ immune systems could lead to powerful human medicines.” The Washington Post, 8 March 2022
  • “Why shark consumption is unhealthy — Shark Conservation Australia.” Shark Conservation Australia.