Giardia intestinalis:: new insights old pathogen

Giardia intestinalis is the most common protozoan enteric pathogen in humans, with an estimated global prevalence of 280 million cases. Sporadic cases and outbreaks of disease are most often associated with consumption or exposure to contaminated water, although food and direct contact with infected hosts (humans or animals) are also important risk factors for disease transmission. Infection with this parasite leads to nutrient malabsorption and severe diarrhoea in adults and children. Infections in children have been shown to have a negative impact on growth and development, and giardiasis has been recognized as a 'neglected disease' by the World Health Organization. Once thought to be a parasite with broad host range, recent molecular evidence suggests that G. intestinalis may display a certain degree of host specificity, reigniting historical debates aboutthe zoonotic potential of this parasite. These findings have major implications for understanding disease transmission and publics health intervention measures aimed at controlling this important cosmopolitan parasite. (c) 2007 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.