Waterborne transmission of protozoan parasites: A worldwide review of outbreaks and lessons learnt

Abstract

At least 325 water-associated outbreaks of parasitic protozoan disease have been reported.North American and European outbreaks accounted for 93% of all reports and nearly two-thirds of outbreaks occurred in North America. Over 30% of all outbreaks were documented from Europe, with the UK accounting for 24% of outbreaks, worldwide. Giardia duodenalis and Cryptosporidium parvum account for the majority of outbreaks (132; 40.6% and 165; 50.8%, respectively), Entamoeba histolytica and Cyclospora cayetanensis have been the aetiological agents in nine (2.8%) and six (1.8%) outbreaks, respectively, while Toxoplasma gondii and Isospora belli have been responsible for three outbreaks each (0.9%) and Blastocystis hominis for two outbreaks (0.6%). Balantidium coli, the microsporidia, Acanthamoeba and Naegleria fowleri were responsible for one outbreak, each (0.3%). Their presence in aquatic ecosystems makes it imperative to develop prevention strategies for water and food safety. Human incidence and prevalence-based studies provide baseline data against which risk factors associated with waterborne and foodborne transmission can be identified. Standardized methods are required to maximize public health surveillance, while reporting lessons learned from outbreaks will provide better insight into the public health impact of waterborne pathogenic protozoa.

Cryptosporidium: from laboratory diagnosis to surveillance and outbreaks

“…Between 1983 (when surveillance for Cryptosporidium began) and 2005, a total of 151 Cryptosporidium outbreaks involving 9893 cases illness were reported to CfI, involving many vehicles for infection, including public water supplies (56 outbreaks), private water supplies (6), swimming pools (44), other recreational waters (7), animal contact and farms (19), food (4), person-to-person spread (10) and unknown (5). Cryptosporidium clearly plays a particular role in waterborne disease, facilitated by many inherent biological features, reported elsewhere (Karanis et al, 2007). In a review of 89 outbreaks of waterborne disease involving 4,321 cases in England and Wales , Cryptosporidium was the causative agent in 69 %.…”

Cryptosporidiosis: a neglected infection and its association with nutritional status in schoolchildren in northwestern Mexico

“…Its transmission has been associated with contaminated drinking water and food, low socioeconomic status and overcrowding conditions [2]. C. parvum has a cosmopolitan distribution and its prevalence can range from 0.1% to 31.5% in developing countries [3]. Human cryptosporidiosis can be accompanied by abdominal pain, fever, vomiting, malabsorption and diarrhea [4] that may lead to undernutrition, as found in children in West Africa and South America [5] and in Bangladesh [6].…”

Detection of Toxoplasma gondii oocysts in water: proposition of a strategy and evaluation in Champagne-Ardenne Region, France

“…Protozoan agents are very robust in water environments and are strongly resistant to most disinfectants, including chemical procedures (like chlorination) used to disinfect drinking water. Over the last 30 years, giardiasis has become the most common cause of human waterborne disease in the United States (Furtado et al 1998, Karanis & Kourenti et al 2007). However, waterborne cryptosporidiosis outbreaks have also been reported during that time, including one in Milwaukee in 1993 affecting 403,000 people (Mc Kenzie et al 1994).…”