The risks of mixing with sewage

By Dr Dave Baglow

SAS Regional Reps

Human sewage contains bacteria and viruses (pathogens) that have previously grown inside another person. This means that they are accustomed to the human body and how to make it a home. This means they are able to make your body a home too. The average adult contains over 1Kg of bacteria. The vast majority causes no harm and some are even helpful to your body. Pathogens that cause no problem to the body in one area (gut for example) can cause serious infections if they are able to infect other areas of the body.

Sewage can also contains pathogens from animals (drainage from livestock) and these also have the potential to cause us harm.

Stomach upsets

Swallowing water contaminated with bacteria or viruses can cause gastroenteritis. This typically presents with symptoms of diarrhoea and vomiting. After being swallowed, these unfriendly organisms in the seawater grow inside your digestive system. The diarrhoea and vomiting is in response to inflammation of the stomach, small intestine and occasionally the colon.

The symptoms of vomiting, abdominal cramps and diarrhoea typically occur within 12 to 72 hours of exposure to the offending bacteria or virus. Viral infections usually resolve quicker than bacterial ones, which can last up to four weeks.

It used to be thought that the vomiting and diarrhoea was the body’s way to get rid of the toxins from your body. However, there is no evidence that taking drugs to stop you vomiting or having diarrhoea prolong the illness.

The vast majority of people with gastroenteritis get better without treatment and don’t need to have medication. Dehydration is the biggest problem and having sips of water is important. It is extremely uncommon for adults to need admission to hospital for intravenous fluid to replace the fluid they have lost in their vomit and diarrhoea.

What else could it be?

  • Appendicitis
  • Urinary tract infection

Skin infections

Skin acts as a natural barrier to potentially harmful organisms. Damage to skin in the form of cuts and grazes result in this barrier being broken, and pathogens (bacteria & viruses) then have the potential to enter the body at this site.
When sewage contaminated water comes into contact with damaged skin the bacteria in the water can cause an infection. A painful and itchy rash can develop. If the infection develops the area can become hot and swollen and may start weeping pus. Pus is the product of your bodies immune systems (often failing) attempt to destroy the multiplying bacteria. If left on its own most minor skin infections get better on their own if left clean and dry, but some can progress and make you feel unwell and cause a fever. Cleaning the area thoroughly is very important.

Ear infections

The longer seawater stays in your ear (ear canal) the more chance you have of developing an outer ear infection. This is why people who suffer from surfers ear are prone to infection, because it slows down the ears ability to drain water. If there are an increased amount of bacteria and viruses in the water (from sewage) it also increases the chances of infection.

Ear infections cause pain in the affected ear and cause a significant loss in hearing. This hearing loss resolves once the infection clears. If left untreated the infection can become extremely uncomfortable and spread to the skin around the ear and on the face. This infection of the skin can make you feel extremely unwell and cause a fever. Unfortunately antibiotics don’t make much of a difference to make a simple outer ear infection get better, but can help prevent a persistent one from spreading to surrounding skin.

Do not try and clean your ear with cotton buds as this irritates the skin and increases the chance of infection. Ear infections are a serious problem that plague many surfers and keep them out of the water. Wearing earplugs designed for surfing greatly reduces the chances of infection (and developing surfers ear).

Eye infections

Normally the eye is well protected from infection. We blink, have tears that wash away pathogens and the tissue protecting the eye is surprisingly robust. Irritation to the eye during surfing is common. Sand, bright sunlight, wind and seawater can cause the eye to become inflamed. Sewage water contains bacteria and viruses that are able to infect the inflamed area. Sewage is known to contain viruses such as adenovirus. This virus in particular is able to cause a nasty infection of the eye.

When an eye is infected it becomes red and the conjunctiva, the tissue surrounding the eye becomes red and swollen (conjunctivitis). The eye becomes watery and weeps. Tears are your body’s natural attempt to wash away infection. You do not need to have pus discharging from your eye to have an eye infection. Eye infections are often very uncomfortable. The discomfort is often described as feeling like you have small grains of glass in the eye.

Eye infections are easy to treat with eye drops, but if left untreated they can progress and become extremely unpleasant. If you have difficulty seeing/reading normally out of the effected eye, or there is pain on movement then you should seek urgent medical attention. Often infection starts in only one eye but is easily spread to the other eye. Regular hand washing is important to prevent this.

Sewage polluted sea water can cause sore throats. This is virtually always viral. Known as the common cold. Inflammation of the upper airway often spreads to the eye via small ducts and can cause red weeping eyes. This isn’t true infection of the eye, but is a result of inflammation.

Sore throat

Sewage contaminated water contains viruses. These viruses are able to infect your upper airway causing pain on swallowing. The common cold is a viral infection of the upper airways. It isn’t however always the same virus. It is extremely common to suffer from symptoms of a common cold after surfing in sewage-contaminated water. The illness is usually mild and resolves after a few days.

Chest infections

When waves break small particles of water are ejected into the air and the mist (aerosol) is breathed in by surfers and other water users. If the water is contaminated by sewage its pathogens are able to be inhaled and have the potential to infect the lungs and airway. Due to a lack of awareness and research it is not known how common problem chest infections are to people who surf in sewage contaminated water. It is known however that it does occur and, when it does, the infections can be extremely severe and make you very unwell.


The liver plays a vital role in the body. Breaking down toxins, creating proteins and storing energy to name only a few.

Hepatitis means inflammation of the liver. Damage to liver cells exposes them to the body’s immune system and the cells of the immune system cause inflammation. Inflammation is actually a normal part of the process of healing. Because of the nature of the contents of the liver cells this inflammation may become quite profound and unhelpful for the recovery of the liver. The inflammation itself can then stop the liver working normally.

Just like some viruses are particularly suited to causing inflammation of your throat (common cold viruses), some are also particularly good at causing profound inflammation of your liver. These are the hepatitis viruses and there are quite a few. They are named from A to G plus one called TT. There are also lots of other viruses that can cause major inflammation of the liver (hepatitis) such as Dengue and Herpes simplex. The hepatitis viruses vary in how they are transmitted, how long they take to make you ill, how severe they are and whether or not they can keep reoccurring.

The time the virus takes to reveal itself can take from 15 to 50 days. During which time the virus is replicating in the liver and shedding itself into your faeces. This is how it is spread to others.

What are the symptoms?


  • Reduced appetite
  • Feeling nauseated
  • Vomiting
  • Fever
  • Shivers
  • Weakness
  • Headache
  • General aches and pains
  • Abdominal pain

These symptoms are then usually followed by jaundice. Jaundice occurs when levels of bile pigments in the blood increase and skin and eyes become noticeably yellow. The liver normally helps with the removal of these pigments from the body, and when it’s inflamed it stops to work as well. Jaundice usually lasts for up to three weeks with hepatitis A. Once these pigments reach a certain level they can cause you to itch.

  • Your stools can become pale (lacking pile pigment) and
  • your urine can become dark (increased bile pigment in urine)

If the virus is able to establish itself it can last for weeks. During this time (depending on the virus and other illness that may also be present) the liver may deteriorate significantly in its ability to perform its normal functions. This is known as ‘failure’. Liver failure, although only occurring in 1% of cases of hepatitis A, is an extremely dangerous situation. It has serious implications for the other major organs in your body, including your brain. If hepatitis becomes severe it can cause confusion, a reduced level of consciousness or even coma.

Hepatitis A is a virus frequently found in sewage. Sewage workers are advised to vaccinate themselves against the virus. So too are surfers you regularly surf in sewage polluted water. In children the disease is usually mild, but can be much more serious and prolonged in adults. Virtually all people that suffer from hepatitis A go on to make a full recovery.

There is a vaccine available for hepatitis A. It provides cover for roughly a year. If a booster vaccine is had about a year after the first one then cover can last for about twenty years. If you were concerned that you may have contracted hepatitis it would be extremely wise to visit your GP.

E Coli

E coli is an abbreviation of Escherichia coli, bacteria that occurs naturally in the lower intestines of mammals (including us). It has been around for thousands of years and over the years it has developed a huge amount different varieties of itself. They differ in their structure, ability to survive outside of a host and the proteins that they produce. The differences can be so large that you could argue that they are not the same group of bacteria. Most varieties of the bacteria are harmless, occurring naturally in us, and can actually be quite useful by fighting off other potentially harmful bacteria and by helping generate vitamins.

There are some varieties however that can cause harm to humans. One such variety is Enterohaemorrhagic E coli. We are familiar with hearing about E coli 0157:H7 in the media. This is an enterohaemorrhagic variety of E coli. This bacterium creates a protein, which acts as a toxin in the human body. It can exist in other mammals such as pigs causing them no harm. This toxin causes abdominal pain and aggressive diarrhoea and vomiting. If it progresses the toxin can cause damage to blood vessels in the skin causing a distinctive rash and vessels in the kidneys causing a serious and potentially life threatening illness.

E coli is spread by the ‘faecal-oral’ route. Any way for faeces to be able get in your mouth has the potential to spread E coli. This includes sewage-contaminated seawater. In the media we often read about butcher shops that are contaminated with the bacteria. Butcher shops work under strict hygiene laws and when followed, it is actually extremely rare for this to be a problem.

How this contamination of your gut affects you will depend on the strain of E coli and whether it is able to out-compete the E coli that already exists in your gut. The worst you experience may be just a slightly looser stool motion. Only a few strains of E coli have the potential to cause significant harm.