Waterborne Human Pathogenic Viruses in Complex Microbial Communities: Environmental Implication on Virus Infectivity, Persistence, and Disinfection

Abstract

Waterborne human pathogenic viruses challenge global health and economy. Viruses were long believed to transmit among hosts as individual, free particles. However, recent evidence indicates that viruses also transmit in populations, so-called en bloc transmission, by either interacting with coexisting bacteria, free-living amoebas, and other higher organisms through endosymbiosis and surface binding, or by being clustered inside membrane-bound vesicles or simply self-aggregating with themselves. En bloc transmission of viruses and virus−microbiome interactions could enable viruses to enhance their infectivity, increase environmental persistence, and resist inactivation from disinfection. Overlooking this type of transmission and virus−microbiome interactions may underestimate the environmental and public health risks of the viruses. We herein provide a critical perspective on waterborne human pathogenic viruses in complex microbial communities to elucidate the environmental implication of virus−microbiome interactions on virus infectivity, persistence, and disinfection. This perspective also provides insights on advancing disinfection and sanitation guidelines and regulations to protect the public health.

Vesicle-Cloaked Rotavirus Clusters are Environmentally Persistent and Resistant to Free Chlorine Disinfection

“…All water samples were filtered with 0.22 μm membranes to remove large particles and bacteria, protists, protozoa (like amoebas), zooplanktons, and other higher organisms immediately after sample collection and then stored at −80 °C for further experiments. We focus on the physical and chemical stability of rotavirus vesicles under different water chemistries and potential exposure to enzymes (e.g., proteolytic enzymes secreted by bacteria) by excluding the impact of microbial grazing . Water quality parameters are listed in Table S1.…”

“…We focus on the physical and chemical stability of rotavirus vesicles under different water chemistries and potential exposure to enzymes (e.g., proteolytic enzymes secreted by bacteria 22 ) by excluding the impact of microbial grazing. 23 Water quality parameters are listed in Table S1. To evaluate the short-and long-term stability of rotavirus vesicles, 10 μL of rotavirus vesicles were seeded to 90 μL of filtered freshwater and wastewater and settled at room temperature in the dark for up to 7 days and 16 weeks without mixing.…”

Breakpoint Chlorination Enhances the Disinfection of Amoeba Spores and Their Intraspore Bacteria

“…Amoebae, such as Acanthamoeba , Echinamoeba , and Naegleria fowleri , are widely detected in water, − which can threaten public health by causing brain or eye infections. , Amoebae act as environmental vectors and can carry human pathogenic bacteria (e.g., Legionella sp ., Pseudomonas aeruginosa , and Mycobacterium ) and viruses (adenovirus, norovirus, and reovirus), which enhances the environmental persistence and resistance of these pathogens to disinfection. , For example, both viable and dead amoeba spores protected their intraspore bacteria from common disinfection treatments, including chlorine, chlorine dioxide, and UV treatment . Moreover, amoebae contribute to the multiplication of pathogenic bacteria, such as Helicobacter pylori , Legionella pneumophila , and Candida spp.…”

Uptake without inactivation of human adenovirus type 2 byTetrahymena pyriformisciliates

“…Human adenoviruses are frequent contaminants of surface water that can cause diseases such as gastroenteritis, respiratory illness and conjunctivitis 1 . In the aqueous environment, the fate of adenoviruses is in part determined by indigenous microorganisms including protists [2][3][4][5] . The interactions of protists with waterborne viruses are manifold, ranging from virus inactivation 6,7 to protection and transport 8 , and possibly the induction of higher pathogenicity as demonstrated for a fish virus 9 .…”