Risk of faecal pollution among waste handlers in a resource-deprived coastal peri-urban settlement in Southern Ghana

The plastisphere can protect Salmonella Typhimurium from UV stress under simulated environmental conditions

Plastic waste is found with increasing frequency in the environment, in low- and middle-income countries. Plastic pollution has increased concurrently with both economic development and rapid urbanisation, amplifying the effects of inadequate waste management. Distinct microbial communities can quickly colonise plastic surfaces in what is collectively known as the 'plastisphere'. The plastisphere can act as a reservoir for human pathogenic bacteria, including Salmonella enterica sp. (such as S. Typhimurium), which can persist for long periods, retain pathogenicity, and pose an increased public health risk. Through employing a novel mesocosm setup, we have shown here that the plastisphere provides enhanced protection against environmental pressures such as ultraviolet (UV) radiation and allows S. Typhimurium to persist at concentrations (>1 × 103 CFU/ml) capable of causing human infection, for up to 28 days. Additionally, using a Galleria Mellonella model of infection, S. Typhimurium exhibits greater pathogenicity following recovery from the UV-exposed plastisphere, suggesting that the plastisphere may select for more virulent variants. This study demonstrates the protection afforded by the plastisphere and provides further evidence of environmental plastic waste acting as a reservoir for dangerous clinical pathogens. Quantifying the role of plastic pollution in facilitating the survival, persistence, and dissemination of human pathogens is critical for a more holistic understanding of the potential public health risks associated with plastic waste.

Enduring pathogenicity of African strains of Salmonella on plastics and glass in simulated peri-urban environmental waste piles

In low- and middle-income countries, plastic has become a major constituent of landfills and urban dump sites. Environmental plastic pollution can also provide a novel surface for the formation of microbial biofilm, which often includes pathogenic bacteria and viruses. Here, under conditions simulating a peri-urban waste pile typical of an African informal settlement, we aimed to determine if pathogenic Salmonella spp. can retain their virulence following a prolonged period of desiccation on the surfaces of environmental plastic and glass. We show that clinically (and environmentally) relevant strains of Salmonella including S. Enteritidis, S. Typhimurium and S. Typhi can persist on plastic and glass for at least 28-days and that temperature (which increases with the depth of an urban waste pile) is a key determinant of this survival. All three strains of Salmonella retained their pathogenicity (determined by using a Galleria mellonella model of infection) following their recovery from the plastisphere indicating that plastics in the environment can act as reservoirs for human pathogens and could facilitate their persistence for extended periods of time. Pathogens colonising environmental plastic waste therefore pose a heightened public health risk, particularly in areas where people are frequently exposed to plastic pollution.

Contamination of herbal medicinal products in low-and-middle-income countries: A systematic review

The use of herbal medicinal products (HMPs) has grown significantly across low-and-middle-income countries (LMICs). Consequently, the safety of these products due to contamination is a significant public health concern. This systematic review aimed to determine the prevalence, types, and levels of contaminants in HMPs from LMICs. A search was performed in seven online databases, i.e., Africa journal online (AJOL), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Directory of Open Access Journals (DOAJ), Health Inter-Network Access to Research Initiative (HINARI), World Health Organization Global Index Medicus (WHO GIM), Scopus, and PubMed using appropriate search queries and reported as per the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA) guidelines. Ninety-one peer-reviewed articles published from 1982 to 2021 from 28 different countries across four continents were included in the study. Although metals, microbial, mycotoxins, pesticides, and residual solvents were the reported contaminants in the 91 articles, metals (56.0%, 51/91), microbial (27.5%, 25/91), and mycotoxins (18.7%, 17/91) were the most predominant. About 16.4% (1236/7518) of the samples had their contaminant levels above the regulatory limits. Samples tested for microbial contaminants had the highest proportion (46.4%, 482/1039) of contaminants exceeding the regulatory limit, followed by mycotoxins (25.8%, 109/423) and metals (14.3%, 591/4128). The proportion of samples that had their average non-essential metal contaminant levels above the regulatory limit was (57.6%, 377/655), 18.3% (88/480), 10.7% (24/225), and 11.3% (29/257) for Pb, Cd, Hg, and As, respectively. The commonest bacteria species found were Escherichia coli (52.3%, 10/19) and Salmonella species (42.1%, 8/19). This review reported that almost 90% of Candida albicans and more than 80% of moulds exceeded the required regulatory limits. HMP consumption poses profound health implications to consumers and patients. Therefore, designing and/or implementing policies that effectively regulate HMPs to minimize the health hazards related to their consumption while improving the quality of life of persons living in LMICs are urgently needed.

Serosurvey of hepatitis A virus and E virus infection among municipal sweepers working in the largest city in the south of Iran

This study was conducted to determine the exposure rate of Hepatitis A and Hepatitis E viruses in urban solid waste collectors/sweepers in the south of Iran. The 385 samples (serums) were collected from Shiraz Municipality waste sweepers.. A questionnaire was used to gather data on their demographic and occupational characteristics, as well as their awareness of viral hepatitis disease. The viral seroprevalence was determined by commercial IgG ELISA kit. All participants were male, mean age of 41 ± 8 years. ELISA assay showed that all of them were positive for anti-HAV IgG. Also, 62 out of 385 individuals were positive for anti-HEV IgG. The statistical analysis showed that the frequency of HEV IgG antibody among age groups 20-30, 31-40, 41-50 and >50 years old had an increasing trend, 4.5%, 10.1%, 17.4%, and 36.7%, respectively, indicating age factor significance (p = .001). Based on some investigated factors including the duration of work experience, current and previous jobs, habitation, personal hygiene status, and knowledge on viral hepatitis diseasees/their transmission, there was no statistically significant difference between anti-HEV IgG positive versus negative sweepers. The results indicated a slighty higher frequency of anti-HAV and anti-HEV IgG among sweepers compared to other pre-investigated population. It doesn't seem that garbage collecting/sweeping could be a significant risk factor for HAV and HEV infection.

The Incidence, Intensity, and Risk Factors for Soil Transmissible Helminthes Infections among Waste Handlers in a Large Coastal Periurban Settlement in Southern Ghana

Soil-transmissible helminthes (STH) infections are among the most common sanitation-related public health problems in poor periurban settlements of tropical regions of low- and middle-income countries. In Ghana, research studies documenting the incidence rate, intensity, and occupational risk factors of STH infections among adults are scanty. A prospective cohort study of 261 waste handlers was conducted to investigate this. Stool samples were collected after 90 and 180 days of treatment with albendazole (400 mg per dose). The geometric mean intensity of STH among waste handlers after 180 days of treatment was 2.8 eggs/gram (light intensity), with an incidence rate of 1.5%. The proportion of waste handlers with light intensity STH infections was 4.8%. The odds of STH infection among female waste handlers were 80% lower when compared with male waste handlers (aOR = 0.2; 95% CI: 0.0–0.8). Waste handlers who used rubber gloves when working were 80% (aOR = 0.2: 95% CI: 0.2–1.9) protected from STH infections compared with those who did not use gloves. Infections with STH among the 261 waste handlers significantly correlated with the type of waste handling activities (LR χ² = 15.3; p=0.033) with the highest proportion of infection found among transporters, 2 (40%). Waste handlers should receive periodic antihelminthic treatment, at least once every six months, practice adequate hand hygiene, and use suitable personal protective equipment during work.