The disposal of sewage in significant quantities poses a health hazard to aquatic ecosystems. These effluents can contain
a wide range of pathogens, making faecal contamination a leading source of waterborne diseases around the world. Yet
monitoring bacteria or viruses in aquatic environments is time consuming and expensive. The standard indicators of faecal
pollution all have limitations, including difficulty in determining the source due to lack of host specificity, poor connection
with the presence of non-bacterial pathogens, or low environmental persistence. Innovative monitoring techniques are sorely
needed to provide more accurate and targeted solutions. Viruses are a promising alternative to faecal indicator bacteria for
monitoring, as they are more persistent in ambient water, more abundant in faeces, and are extremely host-specific. Given
the range of viruses found in diverse contexts, it is not easy to find one “ideal” viral indicator of faecal pollution; however,
several are of interest. In parallel, the ongoing development of molecular techniques coupled with metagenomics and bioinformatics
should enable improved ways to detect faecal contamination using viruses. This review examines the evolution
of faecal contamination monitoring with the following aims (i) to identify the characteristics of the main viral indicators of
faecal contamination, including human enteric viruses, bacteriophages, CRESS and plant viruses, (ii) to assess how these
have been used to monitor water pollution in recent years, (iii) to evaluate the reliability of recent detection methods of such
viruses, and (iv) to tentatively determine which viruses may be most effective as markers of faecal pollution.
The COVID-19 pandemic has caused unprecedented health,
social, and economic crises worldwide. However, to date, there
is an only a limited effective treatment for this disease. Human
placenta hydrolysate (hPH) has previously been shown to be
safe and to improve the health condition in patients with hyperferritinemia
and COVID-19. In this study, we aimed to
determine the antiviral effects of hPH against SARS-CoV-2
in vitro and in vivo models and compared with Remdesivir,
an FDA-approved drug for COVID-19 treatment. To assess
whether hPH inhibited SARS-CoV-2 replication, we determined
the CC50, EC50, and selective index (SI) in Vero cells
by infection with a SARS-CoV-2 at an MOI of 0.01. Further,
groups of ferrets infected with 105.8 TCID50/ml of SARS-CoV-2
and treated with hPH at 2, 4, 6 dpi, and compared their clinical
manifestation and virus titers in respiratory tracts with
PBS control-treated group. The mRNA expression of immunerelated
cytokines was determined by qRT-PCR. hPH treatment
attenuated virus replication in a dose-dependent manner in
vitro. In a ferret infection study, treatment with hPH resulted
in minimal bodyweight loss and attenuated virus replication
in the nasal wash, turbinates, and lungs of infected ferrets.
In addition, qRT-PCR results revealed that the hPH treatment
remarkably upregulated the gene expression of type I
(IFN-α and IFN-β) and II (IFN-γ) IFNs in SARS-CoV-2 infected
ferrets. Our data collectively suggest that hPH has antiviral
efficacy against SARS-CoV-2 and might be a promising
therapeutic agent for the treatment of SARS-CoV-2 infection.