By: Pooja Sharma

The old adage about having oysters only during months that have the letter ‘R’ in the word is updated and the reason could be something that you haven’t thought of. Two foodborne pathogens – Vibrio and Cryptosporidium are increasingly becoming more prevalent as a result of climate change. Global Warming is continuously warming up the coastal waters which is providing the perfect breeding ground for many pathogens especially these two.

The report was published in Nutrition Action Healthletter which is a flagship publication of the Centre for Science in the Public Interest, a consumer advocacy nonprofit. Glenn Morris, who is the Director of the Emerging Pathogens Institute at the University of Florida, said that these two foodborne pathogens are probably influenced by global warming. Climate change has certainly increased your odds of getting some nasty bouts of food poisoning.

The bacteria is spreading to the North….

Vibrio is extremely temperature sensitive and there is a steady increase in the number of cases. Vibrio is now found in both the west and east coasts of United States and even in Alaska. The Vibrio has increased in prevalence in the North in the last 50 years.

Heavier Rainfall is also leading to an increase in microscopic parasites….

Scientists are also worried about how the weather changes will affect the water organisms especially Cryptosporidium. Any heavy rainfall as a result of climate change can wash out these microscopic parasites easily out of the contaminated soil and bring into the drinking water supplies and groundwater, the researchers suggested.


Vibrio is a kind of bacteria that generally infects shellfish in coastal waters. People who get ill by this foodborne pathogen generally become infected by consuming raw or undercooked shellfish especially oysters. Vibriosis is responsible for an estimated 80,000 illnesses and 100 deaths annually in the United States, according to the Centers for Disease Control and Prevention. Vibrio species can also cause skin infection among some individuals when they get exposed to the bacteria through brackish or salt water. Brackish water is actually a mix of fresh and sea water which you can find where river meets the sea.

Vibrio bacteria naturally occurs in the coastal areas but are present in higher concentration in the months of May to October. Most of the Vibrio infections and outbreaks occur at this time too. During these months the temperature of the sea is warmer and thus, the sea forms a perfect breeding ground for the bacteria. The most common species of Vibrio that can cause illness is Vibrio vulnificus, Vibrio parahaemolyticus and Vibrio alginolyticus.

The first species of the pathogen – Vibrio Vulnificus can cause the most serious infection. The person who gets infected can become seriously ill, need intensive care or sometimes, limb amputation. It can directly infect the bloodstream causing a life-threatening illness. About half of infections caused by this pathogen are fatal and death can occur within 2 days. It can enter the body both via food and contact with brackish water. Some forms of Vibrio is also responsible for Cholera.

The incubation period of Vibrio Vulnificus is 1-7 days while that of Vibrio parahaemolyticus is 2-48 hours. The symptoms of this infection includes diarrhea, vomiting, abdominal pain and in severe cases the symptoms can be sudden chills, shock, fever and lesions. If you develop sudden symptoms after coming in contact with brackish water or eating oysters then do contact your doctor.

Tips for preparing and cooking oysters properly:

  • Order oysters at restaurants that are properly cooked.
  • Discard any oysters with open shells. Boil the remaining oysters for 3-5 minutes and discard any that does not open.
  • Boil the oysters until the edges curl. Fry at 375 degrees for 3 minutes. Ake at 450 degrees for 10 minutes and broil 3 inches from heat for 3 minutes.


When Cryptosporidium parasite enters your body, it travels down to your intestinal tract and settle onto the walls of your intestine. Once it gets burrowed into the walls of your intestine, more cells are produced which are eventually shed into your feces. The incubation period is within a week after the parasite enters your body. The symptoms of the infection includes watery diarrhea, dehydration, lack of appetite, ever, nausea, abdominal cramps etc. The infection can be serious for high risk individuals.

The causes of the infection can be drinking contaminated water, eating contaminated food, swimming in contaminated water and accidentally swallowing it, having close contact with animals or humans that have the infection can also infect you. Prevention involves practicing good hygiene and thoroughly washing your hands. You should completely refrain from swimming in case you have diarrhea. Even if you are now cured and no longer suffer from symptoms of Cryptosporidium, it is still crucial to refrain from swimming for at least 2 weeks after the symptoms subside. You can still infect others.

Most of the cases of foodborne illnesses resolve on their own without any need for medication. All you need is lots of rest and lots of fluid. Dehydration becomes a common problem because of vomiting and watery diarrhea. So, it is crucial that you keep your fluid intake high. Some individuals might need medical help such as older people, small children, those with weakened immune system and pregnant women. Complications are rare but do happen. So, you should consult the doctor once. He will treat you depending on your condition.

Previous research has shown that many other pathogens that can cause serious foodborne illness are becoming more and more common as a result of the climate change. There was a study released in 2012 by the European Centre for Disease Prevention and Control that indicated about Campylobacter, E. coli, and Salmonella all thriving in warmer temperature.

But, let’s not lose all the hope because the European Centre for Disease Prevention and Control report also suggested that continued public health efforts can nonetheless prove successful by reducing the infection rates from these pathogens. This suggests that all the people together may be able to counteract any negative changes in the climate successfully.