Cryptosporidium and Giardia in Biogas Wastewater: Management of Manure Livestock and Hygiene Aspects Using Influent, Effluent, Sewage Canal Samples, Vegetable, and Soil Samples

Abstract

Cryptosporidium and Giardia are two water- and foodborne protozoan parasites that can cause diarrheal diseases. Poor microbial quality, sanitation conditions, and hygiene practices at exposure to biogas wastewater are important risk factors for human and animal infection. This study highlights the presence and level of both parasites in the environment in relation to biogas waste reuse in Vietnam. A total of 239 samples were collected from different types of samples in the studied districts in Bac Giang province in 2020 via direct immunofluorescent detection to study the occurrence of Cryptosporidium spp. and Giardia spp. (oo)cysts. Among the samples, Cryptosporidium was found in 19 (7.9%) with concentration from 1.104 to 3.105 oocysts/100 mL, while Giardia in 40 (16.7%) with concentration from 1.104 to 2.106 cysts/100 mL, respectively. In detail, the results show that the percentages of positive detection of Cryptosporidium spp. and Giardia spp. in influent, effluent, sewage canal, and vegetables were 13.1% (11/84), 6.0% (5/83), 15.4% (2/13) and 5.9% (1/17) and 26.2% (22/84), 7.2% (6/83), 7.7% (1/13) and 5.9% (1/17), respectively. The results show a trend of decreasing Cryptosporidium and Giardia densities, without statistical significance. Although these parasites decreased after biogas treatment, the remaining loads observed in biogas effluent can reach the watercourses and soil receiving it. Further investigations are needed to contribute to a general understanding of the risk of protozoan parasites, as well as strategies to control and reduce the contamination of environmental water sources and plants and reduce the burden of the pathogens in biogas wastewater in Vietnam.

Investigating the Occurrence of Soil-Transmitted Parasites Contaminating Soil, Vegetables, and Green Fodder in the East of Nile Delta, Egypt

“…This factor is of great importance in our studied area where the main source of irrigation water is surface water bodies, which can bring the fecal matter of humans and livestock to downstream vegetable farmlands. Most of the buried parasites can remain infective for a long time in soil due to their resistant wall and can be distributed to vegetable farmlands with future liability to infect human hosts [ 36 ]. As in other Sub-Saharan African cities, the lack of adequate sanitation and drainage infrastructure [ 37 ] causes contamination of water bodies used for irrigation, which in turn contaminates the soil that becomes a vehicle for human infection [ 38 ].…”

Cryptosporidium in human-animal-environment interphase at Adama and Asella areas of Oromia regional state, Ethiopia

“…The spread of manure on grazing, and cropland promotes the propagation of infection to large areas and drinking water [ 16 ]. In addition, the use of untreated animal manure for horticulture or vegetable cultivation increases the risk of contamination by Cryptosporidium oocyst and human exposure [ 71 ]. This results in indirect transmission of Cryptosporidium infection in humans from contaminated feed and water [ 6 ].…”