Giardia intestinalis, also called G. lamblia or G. duodenalis, is a flagellated protozoan parasite of humans which frequently coexists with E. histolytica. Giardiasis is a parasitic infection of the intestines which is usually asymptomatic and is self-limiting in healthy individuals. Giardiasis may cause chronic diarrhoea, abdominal cramps, bloating, weight loss and fatigue. People with a weakened immune system may have a longer and more serious illness. The treatment is to take Metronidazole.
The disease is widespread throughout the world, but it is particularly common in areas with poor hygiene conditions. Contamination occurs either indirectly through food or drink, or directly through dirty hands. Water contamination is the commonest form. Person-to-person transmission is common in areas with poor sanitary conditions. In developed countries, localised epidemics may occur due to ingestion of spores originating from contaminated food or unfiltered water, and these are frequently reported in institutions attended by children (nurseries, local authorities).
Giardiasis surveillance in Belgium is carried out by the network of sentinel laboratories. It is not a notifiable disease in Belgium. The number of cases of giardiasis reported by this network each year is between 1,100 and 1,300.
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