Scientists identify first likely transmissible cancer in wild catfish

In 2013, catfish in Lake Memphremagog, which is between Vermont and Quebec, showed a strange problem. Some brown bullhead catfish had raised black spots. A study found that 23% to 37% of these fish had melanoma, a type of skin cancer.

Before this study, experts thought the environment might be to blame. In 2011, Tropical Storm Irene caused flooding, and some wondered if pollution made the fish sick. But the new study suggests something different: the cancer cells might spread from one catfish to another. This is the first known case of transmissible cancer in fish.

Researchers looked closely at the affected catfish. They found that the cancer DNA was very similar in many fish. This means the cancer likely came from one source and spread among them. Scientists are still exploring how this happens but think that the catfish’s behaviour during spawning season might help the spread.

Lake Memphremagog is drinking water for over 175,000 people. However, scientists say there is no risk of this cancer passing to humans.

How much do you know?

What percentage of catfish in Lake Memphremagog showed signs of melanoma?

5% to 10%

23% to 37%

50% to 60%

70% to 80%

What event in 2011 raised concerns about pollution affecting the catfish?

Earthquake

Tropical Storm Irene

Hurricane Sandy

Winter Storm

What type of cancer was found in the catfish?

Lung cancer

Skin cancer

Brain cancer

Liver cancer

What does the study suggest about the spread of cancer among the catfish?

It is contagious

It comes from the environment

It is caused by diet

It is genetic

How many people depend on Lake Memphremagog for drinking water?

100,000

150,000

175,000

200,000

During which season do scientists believe the catfish's behavior might help the spread of cancer?

Winter

Summer

Spring

Spawning season

The study indicated that melanoma in catfish might be transmitted from one fish to another.

True False

Prior to 2013, experts were certain that melanoma was caused by pollution.

True False

Lake Memphremagog is used for drinking water by over 200,000 people.

True False

The cancer found in the catfish was determined to have a similar DNA structure.

True False

Scientists have confirmed the risk of cancer transmission from catfish to humans.

True False

The unusual problem with catfish began in 2011.

True False

In 2013, catfish in Lake Memphremagog showed a strange problem involving spots.

Experts believed that pollution might be to blame for the sick catfish after Storm Irene.

The study found that a percentage between 23% to 37% of fish had cancer.

This is the first known case of cancer in fish.

Scientists say there is no risk of this cancer passing to people.

The cancer DNA in the affected catfish was very in many fish.

This question is required