Vibrio parahaemolyticus infection

About

Vibrio parahaemolyticus is a bacterium naturally found in sea water. It most often causes gastroenteritis (gastro).

Vibrio parahaemolyticus infection can affect anyone. It does not usually spread from person to person. However, person-to-person transmission may occur if there is poor personal hygiene.

Causes

People usually become infected by eating contaminated raw or undercooked shellfish (such as oysters, mussels and clams) or by drinking contaminated water. Eating raw or undercooked fish, crab, prawns and lobster can also cause infection.

Vibrio parahaemolyticus can cause wound infection when sea water contaminates an open wound, but this is less common.

Symptoms

Gastro symptoms associated with Vibrio parahaemolyticus infection include:

• Watery diarrhoea (occasionally bloody diarrhoea)
• Abdominal cramps
• Nausea
• Vomiting
• Fever
• Headache

Symptoms generally develop within 24 hours of consuming the contaminated food or water. But, onset of symptoms can range from 4 hours to 96 hours.

Illness is mild in most people, and usually resolves within 72 hours (but can last from a few hours to 12 days).

You are at risk of more severe illness if you are:

• immunocompromised (including being pregnant)
• have a pre-existing medical condition.

When Vibrio parahaemolyticus infects a wound symptoms may include:

• Pain
• Redness
• Warmth
• Pus or discharge

Diagnosis

If you have gastro symptoms, your doctor will ask you for a stool (faeces or poo) sample for testing.

If you have a wound, your doctor will take a swab from the wound for testing.

Treatment

Most cases of Vibrio parahaemolyticus gastro are usually mild and do not need antibiotic treatment. However, your doctor may prescribe antibiotics if you are experiencing more severe symptoms.

General gastro recommendations include:

• Drink plenty of fluids. Oral rehydration drinks are available from your pharmacist.
• Do not take medications to prevent vomiting or diarrhoea, unless recommended by your doctor.
• Seek medical advice straight away if you develop:
  • dehydration – being thirsty, decreased urination, lethargy, dry mouth, feeling faint on standing
  • fever
  • severe abdominal pain
  • bloody diarrhoea.

Seek medical advice if you have a wound infection.

Prevention

To prevent Vibrio parahaemolyticus infection you should:

• Buy shellfish and oysters from reputable seafood suppliers.
• Ensure you refrigerate these foods immediately after purchasing them.
• Keep raw seafood away from ready to eat or cooked foods.
• Always wash hands with soap and water after handling raw shellfish.
• Avoid eating raw or undercooked seafood such as oysters, especially during warm summer periods or if you are at an increased risk of severe diseases (such as people with immune suppression).
• Avoid using seawater in food preparation methods that do not involve cooking (such as washing vegetables).
• Wash your hands after going to the toilet or after changing a nappy.
• Avoid exposing open wounds to seawater. If wounds are exposed, wash with soap and clean water.

Where to get help

• Your GP (doctor)
• Nurse-on-Call Tel. 1300 606 024 – for expert health information and advice (24 hours, 7 days)
• Department of Health, Victorian Government Tel. 1300 651 160
• Food Safety Hotline Tel. 1300 364 352
• Food Standards Australia New Zealand Tel. (02) 6271 2222