Foodborne Illnesses

Foodborne illnesses also referred to as foodborne diseases, foodborne infections and food poisoning, are a common, yet preventable, public health problem across the globe.

Foodborne illnesses are diseases that are usually infectious and toxic in nature and can range from mild to severe health problems and risks.

What is a food-borne illness?

A food-borne illness is any illness or disease contracted from the food spoilage of contaminated food.

During the food processing cycle, many disease causing organisms can infect and contaminate foods. This can occur from failure to cook food thoroughly or infestations from pests such as rodents and cockroaches in food processing facilities.

According to the US Department of Agriculture (USDA), global food-borne illnesses cost more than US$15.6 billion each year. The Centers for Disease Control and Prevention (CDC) estimated that 76 million illnesses related to food contamination have been reported worldwide from 1999 to 2010, including 325,000 hospitalisation cases and 5,000 deaths. CDC further added that Salmonella, Listeria and Norovirus are among top 5 microbes and pathogens that caused major food-borne diseases around the world.

Types of foodborne illnesses

There are roughly around 250 different foodborne illnesses currently in existence. The majority of these foodborne diseases are caused by:

• Bacteria
• Viruses
• Parasites
• Prions
• Chemicals

Bacteria

Below is a list of the most common food-borne illnesses caused by bacteria:

Salmonella

The CDC reports that salmonella is estimated to cause one million illnesses in the United States alone each year. Globally, the WHO estimate this figure to be around the tens of millions.

The majority of salmonella infections result in developing diarrhea, fever, and abdominal cramps. These causes usually happen 12 to 72 hours after infection.

The majority of salmonella infections usually last between 4 and 7 days, with most patients recovering without treatment. However, there are some cases where the diarrhea becomes quite severe leading to hospitalisation due to dehydration.

Campylobacteriosis

Campylobacteriosis is an infectious disease caused by the bacteria of the genus Campylobacter. It is the main cause of food-borne diarrheal infections, and is the most common bacteria that causes gastroenteritis worldwide.

Most infections result in patients developing diarrhea, cramping, abdominal pain, and a fever within two to five days. The diarrhea can sometimes be bloody and patients can sometimes develop nausea and vomiting as a result of infection.

The infection usually lasts around 1 week. Patients with compromised and weak immune systems can sometimes develop life-threatening infections due to campylobacteriosis spreading to the bloodstream.

Escherichia Coli

Escherichia Coli (E. coli) is a bacterium that is commonly found in the gut of humans. Most strains of E.coli are harmless, however, some strains can cause serious food-borne diseases.

Enterotoxigenic E. coli (ETEC)

ETEC can cause profuse watery diarrhea and abdominal cramping. Other symptoms, which are less common, include:

• Fever
• Nausea with or without vomiting
• Chills
• Loss of appetite
• Headache
• Muscle Aches
• Bloating

The food borne illness usually develops 1-3 days after infection and usually lasts 4 days, with some taking a week or longer to resolve. Symptoms usually only last 3 weeks, with most patients recovering with little to no medical support.

Enterohemorrhagic Escherichia coli (EHEC)

EHEC causes symptoms such as abdominal cramps and diarrhoea, and in some cases progresses to bloody diarrhea. Fever and vomiting may also occur. Symptoms usually occur between 3 and 8 days of contraction with patients typically recovering after 10.

According to the WHO, in a small number of patients (around 10%) EHEC develops into life threatening diseases such as Haemolytic Uraemic Syndrome.

Listeria

The food-borne disease, listeria, is caused by the bacterium Listeria Monocytogenes. This infection can lead to miscarriages and deaths of newborn babies. Although, the number of listeria cases worldwide is quite low, its severe health risks and consequences makes it one of the most serious food borne diseases.

Symptoms usually consist of a fever, fatigue and aches in pregnant women. Other symptoms include headaches, stiff necks, confusion, loss of balance as well as fever and muscle aches.

Vibrio Cholerae

Vibrio Cholerae is responsible for causing cholera. Around 3-5 million cases and over 100,000 deaths occur each year around the world.

The infection is usually mild, but around 5-10% of cholerae cases develop into a severe disease where water diarrhea, vomiting and leg cramps are present. In these cases the rapid loss of body fluids results in dehydration and shock.

Viruses

To add to the food-borne infections transmitted through bacteria, viruses also contribute to certain diseases being spread by food.

Norovirus

Norovirus is a very contagious virus. This food-borne illness causes its patients stomach and intestines to become inflamed resulting in stomach pain, nausea, diarrhea and vomiting.

According to the CDC, norovirus is the most common cause of acute gastroenteritis in the United States. Symptoms for this food-borne disease usually develop between 12 and 48 of infection. However, most people recover within 1 to 3 days.

Parasites

Some parasites which cause food-borne illnesses can only be transmitted through food, others can also infect a subject through direct contact with animals, as well as by entering the food chain via water or soil and contaminated produce.

Food-borne trematodes

Foodborne trematodes is one of those parasites which can only be transmitted through food. According to the WHO, at least 56 million people globally suffer from one or more foodborne trematodiases.

Food-borne trematodiases are caused by the trematode worms. The most common species which affect humans are:

• Clonorchis
• Opisthorchis
• Fasciola
• Paragonimus

Infection is spread through the consumption of produce which harbours the parasite larvae and can result in severe liver and lung disease.

Echinococcosis

Echinococcosis is a parasitic disease caused by the tapeworm of the Echinococcus genus. Infection is spread through consumption of produce harbouring the parasite as well as direct contact with an animal host.

Echinococcosis can affect both the lungs and the liver, depending on where the parasite has nested. If located in the liver symptoms include abdominal pain, nausea and vomiting, whilst infection in the lungs symptoms show as a chronic cough, chest pain and shortness of breath.

The WHO states that treatment of this parasite is often expensive and complicated and may require extensive surgery and/or prolonged drug therapy.

Cryptosporidium

The cryptosporidium parasite is responsible for transmitting the cryptosporidiosis disease (crypto for short) which causes watery diarrhea. Individuals with a weak immune system may experience more severe symptoms and can develop a life threatening illness.

Prions Diseases

Prions diseases or transmissible spongiform encephalopathies (TSE) are infectious agents composed of protein, not living organisms and can survive almost anything. They are a unique food-borne illness as they are associated with specific forms of neurodegenerative disease.

Unlike other forms of foodborne diseases, prions cannot be directly eliminated through the traditional methods such as heating.

Mad cow disease

Mad cow disease (bovine spongiform encephalopathy) is a food-borne infection commonly found in cattle and causes a spongy degeneration in the brain and spinal cord. The disease is believed to be caused by cattle being fed the remains of other cattle in the form of meat and bone meal.

The human version of mad cow disease is called variant Creutzfeldt-Jakob (vCJD). It is believed to be caused by eating beef products contaminated with nervous system tissue such as brain and spinal cord, from cattle infected with mad cow disease.

vCJD is quite hard to diagnose until it has nearly run its course. In the early stages of infection symptoms of depression and loss of coordination become apparent.

Dementia develops in later stages of the illness. Only in advanced stages of the disease can brain abnormalities be detected by MRI scans.

Fatal cases lead to the deterioration of the brain's nerve cells which usually happens after 13 months of the onset of symptoms.

Chemicals

Food contaminated with naturally occurring toxins and environmental pollutions are a major health concern due to their ability to cause food-borne illnesses.

There are a whole range of naturally occurring toxins which can lead to becoming infected with a food-borne disease.

Naturally occurring toxins in food can range from the toxins found in poisonous mushrooms, to the high levels of mycotoxins such as aflatoxin and ochratoxin found in corn and cereals.

Long term exposure to these toxins can severely affect the immune system, and in some cases, cause cancer, according to the WHO.

Persistent organic pollutants

Persistent organic pollutants (POPs) refer to compounds which accumulate in the environment and the human body.

The most well known examples of POPs are dioxins and polychlorinated biphenyls. These are the chemicals released as a result of industrial processes and waste incineration, and are found worldwide in the environment and infect animal food chains.

Humans are at risk by consuming food products contaminated by POPs. Dioxins are extremely toxic. Dioxins cause reproductive and developmental problems and damages to the immune system. They are also known to interfere with hormones as well as cause cancer.

Metals

Food can become contaminated with metals such as lead, calcium and mercury. This happens via pollution of the air, water and soil. These lead to illnesses such as lead and mercury poisoning which can result in neurological and kidney damage.

Of course there are a lot more food borne diseases circulating the world, the ones mentioned above are the most common.