Generality
Giardia lamblia (also known as Giardia intestinalis And G. duodenalis) is a flagellated protozoan responsible for an "intestinal affection known as giardiasis, lambliasis or more simply giardia.
The parasite has a life cycle characterized by a cystic stage (resistant form) and a trophozoitic stage (vegetative form). It is "widespread" all over the world, even if - favored by precarious hygienic conditions - it prefers temperate and tropical regions; for this reason, giardia is much more common in developing countries - where it reaches an "incidence of 20-30% - than in more industrialized nations.
Infection
Transmission occurs through the ingestion of food or water contaminated with parasite cysts; tourists from tropical regions are particularly at risk, where giardia is one of the most common etiological agents responsible for traveler's diarrhea. Giardia can also be transmitted by Human contact, for example when you do not wash your hands properly after going to the toilet or handling diapers. Finally, giardia can be transmitted sexually, as occurs during oral-rectal or oral-genital contact. of infection is in fact high even when the number of ingested cysts is particularly small.
After ingestion, with the help of acidity and gastric proteases, the giardia cysts open, releasing trophozoites that attack the upper tract of the small intestine (duodenum and jejunum). Most parasites then return to the cystic stage by passing through the colon. For this reason it is possible to recognize trophozoites in the duodenal aspirate, while cysts are found in the faeces.
Symptoms
To learn more: Giardiasis Symptoms
In a good percentage of cases, giardia occurs in an asymptomatic form. The appearance and severity of symptoms depend on some individual factors, such as the state of the immune system. Class A immunoglobulins, in particular, inhibit the parasite's adherence to the intestinal walls. It is not surprising, therefore, that the risk categories are represented by children, immunosuppressed and - due to the previously exposed modes of transmission - homosexuals and hospital guests. or orphanages. When giardia takes over, the massive colonization of the intestinal mucosa prevents the correct digestion of the chyme and the absorption of nutrients. This factor, together with the irritative stimulus and cell damage, determines the appearance of the typical symptoms of giardia, ranging from watery diarrhea, devoid of blood and pus, to vomiting, stomach ache, flatulence and the emission of whitish stools. , greasy and malodorous (steatorrhea), with lack of appetite and general malaise; sometimes fever is present. peptic or cholecystopathies. When the infection becomes chronic, it can last for years and be clinically indistinguishable from irritable bowel syndrome, with malabsorption, headache, malaise and general weight loss
Therapy
See also: Medicines for the treatment of Giardiasis
Giardia infection is eradicated with drugs such as metronidazole (Flagyl ®) and tinidazole (Fasigin ®), both of which cannot be administered during pregnancy due to their documented teratogenic effect.
