Findings of Giardia assemblage B and C

Findings of Giardia assemblage B and C. suis in vegetables (Table 2) likely represent direct health risks to people consuming raw vegetables irrigated with the water analyzed. For example, in a study that quantifed diarrhea risk related to wastewater, it TH-302 was found that eating morning glory collected from a wastewater canal represented an infection risk of 100% by Giardia (Ferrer et al., 2012). The health risks of other activities such as collecting morning glory, contact with canal, swimming, and fishing in the wastewater canal was also very high for both Giardia and Entamoeba histolytica, reaching a yearly risk of almost 100%. However, it is still uncertain if these estimated alarming high health risks are real. Indeed, public health is threatened by water pollution through the consumption of microbiologically contaminated food and drinking water. There is therefore a need to classify the major sources of pollution and explain possible modes of disease transmission involving wastewater by identifying and quantifying Cryptosporidum and Giardia species/genotypes. Results herein can be useful in building an intergrated pathogen management strategy aimed at protecting public health where extensive use of wastewater was common. In conclusion, the present study represents new knowledge on prevalence and molecular characteristics of Giardia and Cryptosporidium in environmental sources in Vietnam. Genotyping and subtyping enteric parasites in environment can be an effective supplement to conventional surveillance and epidemiologic tools. Thus, more comprehensive molecularly epidemiological studies in their genetic diversity, transmission route, and zoonotic potential should be conducted in more wide range of hosts in Vietnam.
Conflict of interest
Acknowledgments We are grateful to the staff of the health stations of Hoang Tay and Nhat Tan communes for their great efforts in the support and organization of field activities. Sincere thanks to Dao Thi Ha Thanh for guidance on nucleotide sequence analysis. This work was financially supported in part by the Danish International Development Agency (Danida) through the research capacity building project “Water supply, sanitation, hygiene promotion and health in Vietnam (SANIVAT)—phase II” and the program of the National Centre for Competences in Research (NCCR) North-South, Switzerland.