The Food Safety Issues Of Giardiasis

Giardiasis is a type of gastroenteritis caused by the flagellate parasitic protozoan Giardia duodenalis, also known as Giardia lamblia or Giardia intestinalis. It is a common parasite of the intestinal tract and affects both humans and pets. It is also known as beaver fever.

The incubation period is 3 to 25 days and symptoms include flatulence and belching, smelly burps that smell of eggs, farting, watery diarrhoea, abdominal pain and stomach distention. In some milder cases there is less acute diarrhoea with fatty stools known as steatorrhoea, lassitude and weight loss. The situation can last weeks or even months.

The infective dose is very low and may only require one viable cyst. The main sources are human cases, carriers and animals. Transmission is always by the faecal-oral route. Cases involving food are rarely proven.

Waterborne outbreaks occasionally occur and chlorination without filtration is ineffective. Most laboratories reports of giardiasis in England and Wales affect children, and many of these probably originated abroad. About 500,000 cases of giardiasis are diagnosed every year. About 10 per cent of us with the infection have no symptoms. The parasite is most prevalent in developing countries and is one of the most common gastric diseases caught by backpackers. The reported prevalence of 2 to 7 % in high income countries and 2 to 30 per cent in lower income countries.

The parasite produces two types of protein which allow it to cut through layers of protective mucus lining the gut. This breaks the links knitting the cells together so that the parasite can access the nutrients within them.

The proteins mimicking human proteins are tenascins that regulate and modulate cell adhesion. These help cells break apart when necessary as in wound healing.

Giardiasis is capable of causing inflammation through its activity.

How To Avoid Giardiasis

• When abroad always drink filtered or bottled water
• Follow and practice good hygiene
• Avoid potentially contaminated foods
• Avoid water, both drinking and recreational that may be contaminated
• Clean up after ill people and pets.