Waterborne transmission of protozoan parasites: Review of worldwide outbreaks – An update 2004–2010

Abstract

The present update gives a comprehensive review of worldwide waterborne parasitic protozoan outbreaks that occurred and were published globally between January 2004 and December 2010. At least one hundred and ninety-nine outbreaks of human diseases due to the waterborne transmission of parasitic protozoa occurred and were reported during the time period from 2004 to 2010. 46.7% of the documented outbreaks occurred on the Australian continent, 30.6% in North America and 16.5% in Europe. Cryptosporidium spp. was the etiological agent in 60.3% (120) of the outbreaks, Giardia lamblia in 35.2% (70) and other protozoa in 4.5% (9). Four outbreaks (2%) were caused by Toxoplasma gondii, three (1.5%) by Cyclospora cayetanensis. In two outbreaks (1%) Acanthamoeba spp. was identified as the causative agent. In one outbreak, G. lamblia (in 17.6% of stool samples) and Cryptosporidium parvum (in 2.7% of stool samples) as well as Entamoeba histolytica (in 9.4% of stool samples) and Blastocystis hominis (in 8.1% of stool samples) were detected. In those countries that are likely affected most a lack of surveillance systems is noticeable. However, countries that established surveillance systems did not establish an international standardization of reporting systems.

Rapid detection and simultaneous molecular profile characterization of Acanthamoeba infections

“…The loop-mediated isothermal amplification (LAMP) is a method that does not require thermocyclers and DNA purification procedures. LAMP was recently developed for the diagnosis of Trypanosoma spp., Cryptosporidium spp., Theileria, canine and equine piroplasmosis, Toxoplasma gondii, Giardia duodenalis, Microsporidia, Taenia sp., and Plasmodia (Karanis and Ongerth, 2009) (Baldursson and Karanis, 2011). Further investigations should be conducted to compare HRM and LAMP performances for the detection, quantification, and characterization of Acanthamoeba infections.…”

“…Future analyses should generate reproducible melt curves over time in different settings to build reference databases to store HRM calculations and shapes of the melting profiles for each family or species in order to be challenged against the results of future testing. On the above, larger trials are necessary to confirm the usefulness of HRM for environmental studies and disease management (Baldursson and Karanis, 2011;Karanis and Ongerth, 2009 a The amplification of the ASA.S1 region of the 18S rRNA gene using the primers JDP1 and JDP2 was followed by sequence reactions, capillary electrophoresis, and molecular alignments (Booton et al, 2009, Goldschmidt et al, 2009b. b HRM molecular profiles were directly obtained from the corneal samples.…”

Validation of cell-free culture using scanning electron microscopy (SEM) and gene expression studies

“…Cryptosporidium is transmitted mainly via the faecal oral route and contaminated water and has an infectious dose of as low as 10-100 oocysts (Baldursson and Karanis, 2011;Chappell et al, 2006). Currently, nitazoxanide (NTZ) is approved for treatment of cryptosporidiosis in children and immunocompetent adults in the U.S.A., however treatment failures are common and NTZ is not effective without an appropriate immune response and is therefore ineffective for the treatment of immunocompromised individuals and young children (Gargala, 2008;Rossignol, 2010).…”

Molecular typing ofGiardia duodenalisin humans in Queensland – first report of Assemblage E

“…Giardia intestinalis and Giardia lamblia), is a protozoan enteric parasite that causes acute, watery diarrhoea or giardiasis in 280 million people annually and is a common cause of waterborne outbreaks (Lane and Lloyd, 2002;Baldursson and Karanis, 2011;Painter et al 2015;Einarsson et al 2016). Most infections are selflimiting but chronic infections can lead to weight loss and malabsorption (Ryan and Cacciò, 2013) and infections are associated with stunting (low height for age), wasting (low weight for height) and cognitive impairment in children in developing countries (Berkman et al 2002;Feng and Xiao, 2011).…”