Critters and contamination: Zoonotic protozoans in urban rodents and water quality

Rodents represent the single largest group within mammals and host a diverse array of zoonotic pathogens. Urbanisation impacts wild mammals, including rodents, leading to habitat loss but also providing new resources. Urban-adapted (synanthropic) rodents, such as the brown rat (R. norvegicus), black rat (R. rattus), and house mouse (Mus musculus), have long successfully adapted to living close to humans and are known carriers of zoonotic pathogens. Two important enteric, zoonotic protozoan parasites, carried by rodents, include Cryptosporidium and Giardia. Their environmental stages (oocysts/cysts), released in faeces, can contaminate surface and wastewaters, are resistant to common drinking water disinfectants and can cause water-borne related gastritis outbreaks. At least 48 species of Cryptosporidium have been described, with C. hominis and C. parvum responsible for the majority of human infections, while Giardia duodenalis assemblages A and B are the main human-infectious assemblages. Molecular characterisation is crucial to assess the public health risk linked to rodent-related water contamination due to morphological overlap between species. This review explores the global molecular diversity of these parasites in rodents, with a focus on evaluating the zoonotic risk from contamination of water and wasterwater with Cryptosporidium and Giardia oocysts/cysts from synanthropic rodents. Analysis indicates that while zoonotic Cryptosporidium and Giardia are prevalent in farmed and pet rodents, host-specific Cryptosporidium and Giardia species dominate in urban adapted rodents, and therefore the risks posed by these rodents in the transmission of zoonotic Cryptosporidium and Giardia are relatively low. Many knowledge gaps remain however, and therefore understanding the intricate dynamics of these parasites in rodent populations is essential for managing their impact on human health and water quality. This knowledge can inform strategies to reduce disease transmission and ensure safe drinking water in urban and peri‑urban areas.

The potential risks of Legionella arising from ligature-resistant fixtures

To provide a safe environment, behavioral health settings must adhere to "ligature-resistant" protocols for patients at risk of harm to themselves or others. However, certain bathroom ligature-resistant fixtures alter environmental controls, such as sinks and showerheads, and increase the risk of water-borne pathogens due to low water output settings, highlighting the importance of an interdisciplinary water management program. We describe how ligature-resistant water fixtures may have been associated with a possible case of hospital-associated Legionellosis.

Pathogenic Leptospira and water quality in African cities: A case study of Cotonou, Benin

Leptospirosis is a waterborne zoonosis (60,000 infections and 1 million deaths annually). Knowledge about the disease in the urban context is surprisingly rare, especially in Africa. Here, we provide the first study of leptospires in waters within an African city. A simple centrifugation-based method was developed to screen waterborne leptospires from remote or poorly areas. Major ions, trace elements, stable isotopes and pathogenic Leptospira were then seasonally investigated in 193 water samples from three neighborhoods of Cotonou (Benin) with different socio-environmental and hydrographic characteristics. Firstly, no leptospire was detected in tap waters. Secondly, although surface contamination cannot be excluded, one groundwater well was found leptospire positive. Thirdly, pathogenic Leptospira mainly contaminated surface waters of temporary and permanent ponds (9.5% and 27.3% of total prevalence, respectively). Isotopic signatures suggest that leptospires occurred in pond waters formed at the beginning of the rainy season following low to moderate rainfall events. Nevertheless, Leptospira-containing waters possess physico-chemical characteristics that are similar to the spectrum of waters sampled throughout the three sites, thus suggesting that Cotonou waters are widely compatible with Leptospira survival. The frequent contact with water exposes Cotonou inhabitants to the risk of leptospirosis which deserves more attention from public health authorities.

Single step production of high-purity copper oxide-titanium dioxide nanocomposites and their effective antibacterial and anti-biofilm activity against drug-resistant bacteria

In the present research work, copper oxide-titanium dioxide nanocomposites were synthesized for the first time using advanced pulsed laser ablation in liquid (PLAL) technique for disinfection of drug-resistant pathogenic waterborne biofilm-producing bacterial strains. For this, a series of copper oxide-titanium dioxide nanocomposites were synthesized by varying the composition of copper oxide (5%, 10%, and 20%) with titanium dioxide. The pure titanium dioxide and copper oxide-titanium dioxide nanocomposites were characterized by advanced instrumental techniques. XRD, TEM, FE-SEM, EDX, elemental mapping and XPS analysis results consistently revealed the successful formation of copper oxide-titanium dioxide nanocomposites using PLAL technique. The antibacterial and antibiofilm activities of pure titanium dioxide and copper oxide-titanium dioxide nanocomposites were investigated against biofilm-producing strains of Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa by various methods. Our results revealed that the PLAL synthesized copper oxide-titanium dioxide nanocomposites showed enhanced anti-biofilm and antibacterial activity compared to pure titanium dioxide in a dose-dependent manner against targeted pathogens. Furthermore, the effects of pure titanium dioxide and copper oxide-titanium dioxide nanocomposites on bacterial morphology, biofilm formation, aggregation and their colonization by targeted pathogens were also examined using scanning electron microscopy. Microscopic images clearly showed that the cell envelope of almost all the cells were rumples, rough, had irregularities and abnormal appearance with the major damage being characterized by the formation of "pits". Many depressions and indentations were also seen in their cell envelope and the original shape of Pseudomonas aeruginosa cells changed from normal rod to swollen, large and elongated which indicates the loss of membrane integrity and damage of cell wall and membrane. The findings suggested that PLAL synthesized copper oxide-titanium dioxide nanocomposites have good potential for removal of biofilm or killing of pathogenic bacteria in water distribution network and for wastewater treatment, hospital and environmental applications. In addition, cytotoxic activity of pure TiO₂ and PLAL synthesized copper oxide-titanium dioxide nanocomposites against normal and healthy cells (HEK-293) and cancerous cells (HCT-116) were also evaluated by MTT assay. The MTT assay results showed no cytotoxic effects on HEK-293 cells, which suggest TiO₂ and PLAL synthesized copper oxide-titanium dioxide nanocomposites are non-toxic to the normal cells.

Detection of Human Enteric Viruses in Freshwater from European Countries

The transmission of water-borne pathogens typically occurs by a faecal-oral route, through inhalation of aerosols, or by direct or indirect contact with contaminated water. Previous molecular-based studies have identified viral particles of zoonotic and human nature in surface waters. Contaminated water can lead to human health issues, and the development of rapid methods for the detection of pathogenic microorganisms is a valuable tool for the prevention of their spread. The aims of this work were to determine the presence and identity of representative human pathogenic enteric viruses in water samples from six European countries by quantitative polymerase chain reaction (q-PCR) and to develop two quantitative PCR methods for Adenovirus 41 and Mammalian Orthoreoviruses. A 2-year survey showed that Norovirus, Mammalian Orthoreovirus and Adenoviruses were the most frequently identified enteric viruses in the sampled surface waters. Although it was not possible to establish viability and infectivity of the viruses considered, the detectable presence of pathogenic viruses may represent a potential risk for human health. The methodology developed may aid in rapid detection of these pathogens for monitoring quality of surface waters.