Exploring toilet plume bioaerosol exposure dynamics in public toilets using a Design of Experiments approach.

Bioaerosols generated during toilet flushing can contribute to the spread of airborne pathogens and cross-contamination in indoor environments. This presents an increased risk of fomite-mediated or aerosol disease transmission. This study systematically investigated the factors contributing to increased bioaerosol exposure following toilet flushing and developed an empirical model for predicting the exposure-relevant bioaerosol concentration. Air in a toilet cubicle was sampled by impaction after seeding with Clostridium difficile spores. Design of Experiments (DoE) main effects screening and full factorial design approaches were then employed to investigate the significant factors that heighten the risk of exposure to bioaerosols post-flush. Our findings reveal that the inoculated bacterial concentration (C), time elapsed after flushing (t), lateral distance (d), and mechanical ventilation (v) are significant predictors of bioaerosol concentration, with p-values < 0.05. The interaction term, C × d showed a marked increase in bioaerosol concentration up to 232 CFU/m3 at the closest proximity and highest pathogen load. The interplay of C and t (C × t) demonstrated a time-dependent attenuation of bioaerosol viability, with concentrations peaking at 241 CFU/m3 immediately post-flush and notably diminishing over time. The lateral distance and time post-flush (d × t) interaction also revealed a gradual decrease in bioaerosol concentration, highlighting the effectiveness of spatial and temporal dilution in mitigating bioaerosol exposure risks. Furthermore, there is an immediate rise in relative humidity levels post-flush, impacting the air quality in the toilet environment. This study not only advances our understanding of exposure pathways in determining bioaerosol exposure, but also offers pivotal insights for designing targeted interventions to reduce bioaerosol exposure. Recommendations include designing public toilets with antimicrobial surfaces, optimizing ventilation, and initiating timely disinfection protocols to prioritise surfaces closest to the toilet bowl during peak exposure periods, thereby promoting healthier indoor environments and safeguarding public health in high-traffic toilet settings.

Exploiting constructed wetlands for industrial effluent phytodesalination in Jing-Jin-Ji urban agglomeration, China.

The unsustainable exploitation of water resources and growing salinization impacting China's Beijing-Tianjin-Hebei (Jing-Jin-Ji) agglomeration threatens the region's economic growth and drives the exploration of alternative resources. The region's industries face a financial burden due to increasing constraints on water exploitation and discharge regulations. These have resulted in increased industrial salt concentration rejections/discharges, meanwhile, constructed wetlands (CWs), deployed as a perfunctory receptacle for industrial effluents in the region, are underexploited for treating/removing salts. Also, halophytic plants local to the region have promising chloride uptake (60.6 g/kg and 256.0 g/kg of plant dry weight) and can reduce water conductivity by 40%. Exploitation of CWs, using local halophytes has not been explored for phytodesalination purposes in the region. Hence, this study analyses the water resource and salinization crisis in the agglomeration and further evaluates workable potential and critical technical considerations for using local halophytes in CWs to treat industrial salt-laden effluents. While acknowledging this intervention for removing industrial effluent salt may not meet compliance in the region, effluent post-phytodesalination presents opportunities for industries to meet regulatory stipulations on water reuse rates. Furthermore, such effluent may be used for irrigation and can ameliorate the salinization and groundwater exploitation crisis as a cleaner recharge source.

The exploitation of phytoremediation via local halophytes for treating salt-laden industrial water discharges, with specific reference to the Beijing-Tianjin-Hebei (Jing-Jin-Ji) urban agglomeration, has not been explored nor reported in the literature. This study addresses these critical knowledge gaps, providing new insights and technical considerations for workable large-scale phytodesalination applications for deploying and implementing constructed wetlands using locally available halophytes suited to Jing-Jin-Ji agglomeration. This distinguishes this pertinent study intended to engage researchers, industrials, and other stakeholders in the focus area and beyond. HighlightsThe Jing-Jin-Ji urban agglomeration is facing a salinization crisis.All indexes indicate a decline in groundwater resources and quality.Untapped local halophytes have immense phytodesalination potential: up to 256 g/kg (dry weight) Cl⁻ uptake.Drivers and technical parameters for exploiting constructed wetlands for phytodesalination in the region are discussed.

Toilet plume bioaerosols in health care and hospitality settings: A systematic review.

BACKGROUND: The spread of some respiratory and gastro-intestinal infections has been linked to the exposure to infectious bioaerosols released after toilet flushing. This represents a health hazard and infection risk for immunocompromised patients, health workers and the public, particularly within the health care and hospitality settings. This systematic review provides current knowledge and identifies gaps in the evidence regarding toilet plume bioaerosols and the potential contributory role in spreading infections in health care and hospitality settings. METHODS: The PRISMA guidelines were used. Searches were run in PubMed, Scopus, and Google Scholar from 1950 to 30th June 2021. Searches of global and regional reports and updates from relevant international and governmental organizations were also conducted. RESULTS AND CONCLUSION: The search yielded 712 results, and 37 studies were finally selected for this review. There is a lack of national and international bioaerosol sampling and exposure standards for health care and hospitality settings. Toilet plume bioaerosols are complex in nature, thus, measured bioaerosol concentrations in these settings depend on many variables and may differ for every pathogen responsible for a particular infectious disease. The contact and airborne transmission risks posed by toilet plume bioaerosols also remain unquantified. They are an important pathway that can increase the exposure to enteric and airborne pathogens. Hence, quantitative risk assessment and related research are needed to investigate these transmission risks.

Country-level assessment of agrifood waste and enabling environment for sustainable utilisation for bioenergy in Nigeria.

It is essential to plug inefficiencies due to agrifood losses and wastes, which pose a significant threat to the sustainable supply of nutritional agrifood commodities/products. Country-specific evaluations of the extent of agrifood losses/wastes, including the pathways and impacts on net agrifood production, are crucial to inform interventions, research, policies and investments. This kind of knowledge is scarce in sub-Saharan Africa (SSA) countries, many of which are food insecure. This paper presents an estimation of and the bioenergy potential for agrifood loss and waste (AFW) - the edible and inedible residual biogenic fractions of crops and animal commodities/products - in Nigeria. Our findings reveal that Nigeria generates 183.3 ± 8.9MT of AFW per annum. About 27% of the average annual total domestic supply of edible agrifood commodities/products is lost before reaching markets/consumers. The intrinsic bioenergy potential of the inedible AFW fraction generated annually in Nigeria is estimated to be 1,816.8 ± 117.3PJ; this is sufficient to meet 2030's bioenergy targets and replace a third of its total (grid, off-grid and self-generation) supply targets. However, Nigeria lacks regulatory, policy and institutional frameworks specific to AFW management. This study recommends a sustainable approach to managing AFW, addressing the interlinked challenges of bioenergy production, public health and environmental sustainability. Besides addressing knowledge gaps in the Nigerian agrifood sector, the information generated in this study is well-timed to inform decision-making and policy formulation on decentralised AFW-based bioenergy interventions to achieve energy supply targets in the country by 2030 and beyond. This study is also strategic to guide future research/interventions that align with AFW utilisation/clean energy generation in SSA.

Epidemiology of tungiasis in sub-saharan Africa: a systematic review and meta-analysis.

Tungiasis is a public health disease in many rural and urban slums in sub-Saharan Africa (SSA), primarily affecting children and the elderly. Yet, this disease has received little attention in many sub-Saharan African countries. We conducted a systematic review and meta-analysis to estimate the pooled prevalence of tungiasis and associated risk factors in SSA. We searched AJOL, Google Scholar, Web of Science, and PubMed for population-based studies that reported the prevalence of tungiasis and risk factors in SSA between January 1980 and July 2020. The study employed a random-effects model and heterogeneity to estimate the pooled prevalence and evaluate the Cochran's Q-test respectively across studies that met the inclusion criteria. We screened 104 articles and retrieved 42 full-text articles to evaluate for inclusion in the review. Twenty-seven studies involving 16,303 individuals in seven SSA countries were analyzed. The pooled prevalence of tungiasis in SSA was 33.4% (95% CI: 27.6-39.8), while tungiasis prevalence was 46.5%, 44.9%, 42.0%, 37.2%, 28.1%, 22.7% and 20.1% for Ethiopia, Cameroon, Tanzania, Kenya, Nigeria, Rwanda, and Uganda, respectively. The risk of tungiasis was associated with gender, participants' age groups (4-15 years and ≥60 years), earthen floor, non-regular use of footwear, contact with animals, and residence in rural areas. An integrated approach addressing significant factors in tungiasis prevalence in SSA needs to be designed and implemented by a trans-disciplinary composition of community leaders, health professionals, non-governmental institutions, and policymakers.

Prevalence of Schistosomiasis in a neglected community, South western Nigeria at two points in time, spaced three years apart.

BACKGROUND: In recent years, the prevalence of schistosomiasis, a neglected tropical infection, has increased in underprivileged rural communities characterized by poverty. OBJECTIVE: This cross-sectional community-based study was carried out to determine the prevalence of urinary schistosomiasis in a neglected community of Apojola community, South-Western Nigeria at two points in time, spaced three years apart. METHOD AND RESULTS: A total of 145 participants were screened and 44.1% were diagnosed to have urinary Schistosoma haematobium infection after sedimentation and microscopy. The prevalence of schistosomiasis among females was higher (45.3%) than that among males (42.4%) but not significantly different (0.723). The prevalence of participants with light infection (26%) was significantly higher than those with heavy infection (11.0%). The predisposing factors with statistically significant association with Schistosoma haematobium infection were age (0.000), level of education (0.002), eating/selling of snails (0.037), occupation (0.000), drinking water (0.001), swimming (0.008), and washing in a river (0.019). CONCLUSION: These findings indicate that the study area is still endemic to urinary schistosomiasis after three years of research and school-age children and teenagers are the populations at risk of urinary schistosomiasis. Community health education on the cause, mode of transmission, prevention, and prompt treatment of schistosomiasis is recommended.

Comparative evaluation of conventional and microwave hydrothermal carbonization of human biowaste for value recovery.

This paper compares conventional and microwave hydrothermal carbonization (HTC) of human biowaste (HBW) at 160 °C, 180 °C and 200 °C as a potential technology to recover valuable carbonaceous solid fuel char and organic-rich liquor. Also discussed are the influence of HTC heating methods and temperature on HBW processing conversion into solid fuel char, i.e. yield and post-HTC management, dewaterability rates, particle size distribution and the carbon and energy properties of solid fuel char. While HTC temperatures influenced all parameters investigated, especially yield and properties of end products recovered, heating source effects were noticeable on dewatering rates, char particle sizes and HBW processing/end product recovery rate and, by extension, energy consumed. The microwave process was found to be more efficient for dewatering processed HBW and for char recovery, consuming half the energy used by the conventional HTC method despite the similarity in yields, carbon and energy properties of the recovered char. However, both processes reliably overcame the heterogeneity of HBW, converting them into non-foul end products, which were easily dewatered at <3 seconds/g total solids (TS) (c.f. 50.3 seconds/g TS for a raw sample) to recover energy-densified chars of ≈17 MJ/kg calorific value and up to 1.4 g/l of ammonia concentration in recovered liquor.

Microwaving human faecal sludge as a viable sanitation technology option for treatment and value recovery - A critical review.

The prolonged challenges and terrible consequences of poor sanitation, especially in developing economies, call for the exploration of new sustainable sanitation technologies. Such technologies must be: capable of effectively treating human faecal wastes without any health or environmental impacts; scalable to address rapid increases in population and urbanization; capable of meeting environmental regulations and standards for faecal management; and competitive with existing strategies. Further and importantly, despite its noxiousness and pathogenic load, the chemical composition of human faecal sludge indicates that it could be considered a potentially valuable, nutrient-rich renewable resource, rather than a problematic waste product. New approaches to faecal sludge management must consequently seek to incorporate a 'valuable resource recovery' approach, compatible with stringent treatment requirements. This review intends to advance the understanding of human faecal sludge as a sustainable organic-rich resource that is typically high in moisture (up to 97 per cent), making it a suitable candidate for dielectric heating, i.e. microwave irradiation, to promote faecal treatment, while also recovering value-added products such as ammonia liquor concentrate (suitable for fertilizers) and chars (suitable for fuel) - which can provide an economic base to sustain the technology. Additionally, microwaving human faecal sludge represents a thermally effective approach that can destroy pathogens, eradicate the foul odour associated human faecal sludge, while also preventing hazardous product formations and/or emissions, aside from other benefits such as improved dewaterability and heavy metals recovery. Key technological parameters crucial for scaling the technology as a complementary solution to the challenges of onsite sanitation are also discussed.

Characterization of Solid Fuel Chars recovered from Microwave Hydrothermal Carbonization of Human Biowaste.

Microwave hydrothermal carbonization (M-HTC) is reported in this study as a viable sanitation technology that can reliably overcome the heterogeneous nature of human faecal biowaste (HBW) and realize its intrinsic energy value. Solid chars produced from the M-HTC process at 180°C and 200°C were characterized to further the understanding of the conversion pathways and their physicochemical, structural and energetic properties. The study revealed solid chars recovered were predominantly via a solid-solid conversion pathway. In terms of yield, more than 50% of solid chars (dry basis) can be recovered using 180°C as a benchmark. Additionally, the carbonized solid chars demonstrated enhanced carbon and energy properties following the M-HTC process: when compared to unprocessed HBW, the carbon content in the solid chars increased by up to 52%, while the carbon densification factor was greater than 1 in all recovered chars. The calorific values of the chars increased by up to 41.5%, yielding heating values that averaged 25MJ.kg-1. Thermogravimetric studies further revealed the solid fuel chars exhibited greater reactivity when compared with unprocessed HBW, due to improved porosity. This work strengthens the potential of the M-HTC sanitation technology for mitigating poor sanitation impacts while also recovering energy, which can complement domestic energy demands.

Prevalence of potentially zoonotic gastrointestinal parasites in canine faeces in Ibadan, Nigeria.

BACKGROUND: Humans can get infected through direct or indirect contact with infective stages of zoonotic parasites shed to the environment through dog faeces. OBJECTIVES: This study was designed to investigate the presence of gastrointestinal parasites present in dog faeces shed on the street of Ibadan metropolis, one of the largest cities in Africa. METHODS: Twenty-three locations were randomly selected using grid-sampling method. A total of 203 faecal samples collected from the streets of selected areas were processed for detection of helminth eggs and protozoan oocysts using flotation technique. Eggs/oocysts per gram of faeces was counted using modified McMaster technique. RESULTS: The prevalence of gastrointestinal parasites was 43.3% (88/203). Single and multiple infections were 69 (78.4%) and 19 (21.6%) respectively. The parasites detected were Ancylostoma sp. 24.6% (50/88) Isospora sp. 14.2% (29/88), Toxocara sp. 9.8% (20/88), Uncinaria sp. 2.5% (5/88) and Strongyloides sp, 3.9% (8/88). Ancylostoma sp. (320 × 102 epg) and Uncinaria sp. (5 × 102 epg) had the highest and least intensity respectively. Streets within residential areas having markets had the highest number of positive samples. All the genera of parasites detected in this study have zoonotic potential. CONCLUSION: The high prevalence of zoonotic parasites detected in dog faeces from Ibadan metropolis showed that infected stray dogs roam the streets and constitute potential risk to human health. This study suggests the need for enforcement of laws restraining roaming or straying dogs and proper veterinary care of dogs. FUNDING: None declared.

HISTOPATHOLOGIC PATTERN OF BLADDER CANCERS IN IBADAN SOUTHWEST NIGERIA: AN UPDATE.

BACKGROUND: A study from the University College Hospital, Ibadan, Southwest, Nigeria on bladder cancers had described an increase in the frequency of urothelial carcinoma compared to the earlier reported preponderance of squamous-cell carcinoma. AIM: To provide an update on the histopathologic pattern of bladder cancers in our community and to explore its implications for future health system policies. METHODS: The records of the Ibadan Cancer Registry from January 1997 to December 2014 were reviewed and the data analyzed for the histologic subtypes of bladder cancers diagnosed in the hospital. RESULTS: Two hundred and sixteen bladder tumours were recorded during this period with a male to female ratio of 3.2:1. Complete information was available in 195 cases of which 181 (96.8%) were bladder carcinomas whilst 14 were sarcomas. Of the bladder carcinomas, 68.5%, 19.9% and 11.6% were urothelial carcinomas, squamous cell carcinomas, and adenocarcinomas (AC) respectively. Urothelial carcinoma was more common in all age groups and its peak age of occurrence was in the 51-60 year age group. The peak age for squamous cell carcinoma was in the 41-50 year age group. Mean and median age of occurrence was significantly lower in females in the urothelial and squamous cell carcinomas, but lowest in squamous cell carcinoma [P = < 0.0001]. CONCLUSION: This population study has confirmed urothelial carcinoma as the predominant histotype of bladder cancer in Ibadan, Southwest Nigeria currently and that both urothelial and squamous cell carcinomas occur earlier in women.

HER 2 expression status in gastric carcinomas in Ibadan, Nigeria: a preliminary study using immunohistochemistry.

MATERIALS AND METHODS- Archival formalin fixed paraffin embedded gastric Adenocarcinoma tumour tissue from the Department of Pathology, University College Hospital, Ibadan were studied for HER 2 protein status using immunohistochemistry. RESULTS- HER 2 protein receptor status was determined in 36 cases using immunohistochemistry. The male: female ratio was 1.4:1. The age range of the patients was 30 to 86 years, with peak age-groups being in the 6th and 7th decade of life. Mean age of the patients was 57.6 years while the median age was 56years. Four cases were positive for the HER 2 receptor protein representing about 11% of the cases. Two cases had staining score of 2+ while another 2 cases had score of 3+. The four positive cases were intestinal variants of gastric adenocarcinomas based on Laurens classification. Three were well differentiated tumours and one was moderately differentiated. CONCLUSION- HER 2 protein overexpression by immunohistochemistry can be demonstrated in black Africans with gastric carcinoma. More detailed and multicentre studies will be needed to draw firm conclusions in this regard.

Correlation of cervical cytology and visual inspection with acetic acid in HIV-positive women.

The prevalence of squamous intraepithelial lesion is higher among human immunodeficiency virus (HIV)-positive women. These lesions when they occur in these patients are also more difficult to treat. A total of 205 consenting HIV-seropositive women were recruited. A cervical cytology (Pap smear) was taken, followed by visual inspection with freshly prepared 5% acetic acid and cervical biopsy taken from the squamocolumnar junction as the reference for diagnosis to avoid verification bias. The sensitivity of VIA was 76.0% (95% CI 52.0-91.0); specificity 83.0% (95% CI 77.0-88.0); positive predictive value 34.0% (95% CI 21.0-49.0). The sensitivity of cervical cytology (Pap smear) was 57.0% (95% CI 34.0-77.0), specificity of 95.0% (95% CI 90.0-97.0), and positive predictive value of 55.0% (95% CI 33.0-75.0). In HIV-seropositive women, the sensitivity of VIA is 76.0%, making it a useful screening test for preinvasive lesion of the cervix in low resource settings.

Temporal and biological trends in liver cancers at a University hospital in Southwest Nigeria.

The changes in incidence, sex distribution and histological profile of cancers of the liver over two decades at the University College Hospital (UCH), Ibadan, Nigeria, were studied. There were 1234 cases of liver cancer, consisting of 876 men and 358 women, a men to women ratio of 2.4:1, and peak age incidence was between 40 and 59 years. Hepatocellular carcinoma (HCC) accounted for 92% of all cases; metastatic carcinoma was 1.78%, cholangiocarcinoma 1.2%, while combined HCC and cholangiocarcinoma was 0.24%.

Usefulness of acute phase proteins for monitoring development of hepatocellular carcinoma in hepatitis B virus carriers.

BACKGROUND: Serum levels of acute phase proteins (APP) have been used to diagnose and follow up treatment of liver diseases. This study was carried out to determine the usefulness of APP to predict development of hepatocellular carcinoma (HCC) among Hepatitis B virus (HBV) carriers. STUDY DESIGN: In a prospective study, serum haptoglobin, transferrin and alpha 2 macroglobulin levels of 55 subjects consisting of 20 HBV carriers, 18 HBV-positive HCC patients and 17 controls were determined using single radial immunodiffusion. RESULT: The mean levels of haptoglobin were 141.75mg/dl+/-133.76, 97.11mg/dl+/-92.62,161.59mg/dl+/-146.86 for HBV carriers, HBV-positive HCC and controls respectively. The mean transferrin levels for HBV carriers, HBV-positive HCC and controls were 166.4mg/ dl+/-88.31, 140.0mg/dl+/-68.73 and 270.35mg/dl+/-122.79 respectively while similar values for alpha 2 macroglobulin were 195.4mg/dl+/-93.86, 189.83mg/dl+/-77.19 and 127.53mg/dl+/-43.29. No significant difference in the mean serum haptoglobin levels of HBV carriers and HBV-positive HCC (p=0.526), HBV carriers and controls (p= 0.883) and HBV-positive HCC and controls (p=0.295). The difference between the mean serum transferrin levels was insignificant between HBV carriers and HBV-positive HCC, p= 0.671, but was significant between HBV carriers, and HBV-positive HCC compared with controls, (p=0.005 and 0.000 respectively). No significant difference in alpha 2 macroglobulin between HBV carriers and HBV-positive HCC, (p=0.972), but the differences were significant between HBV carriers, and HBV-positive HCC and controls, (p=0.024 and 0.048 respectively). CONCLUSION: Haptoglobin, alpha 2 macroglobulin and transferrin lack predictive value for development of HCC in HBV carriers. Reduced transferrin and increased alpha 2 macroglobulin in HBV carriers might suggest active liver disease.