One Health monitoring reveals invasive freshwater snail species, new records, and undescribed parasite diversity in Zimbabwe.

BACKGROUND: Snail-borne trematodes afflict humans, livestock, and wildlife. Recognizing their zoonotic potential and possible hybridization, a One Health approach is essential for effective control. Given the dearth of knowledge on African trematodes, this study aimed to map snail and trematode diversity, focusing on (i) characterizing gastropod snail species and their trematode parasites, (ii) determining infection rates of snail species as intermediate hosts for medically, veterinary, and ecologically significant trematodes, and (iii) comparing their diversity across endemic regions. METHODS: A cross-sectional study conducted in 2021 in Chiredzi and Wedza districts in Zimbabwe, known for high human schistosomiasis prevalence, involved malacological surveys at 56 sites. Trematode infections in snails were detected through shedding experiments and multiplex rapid diagnostic polymerase chain reactions (RD-PCRs). Morphological and molecular analyses were employed to identify snail and trematode species. RESULTS: Among 3209 collected snail specimens, 11 species were identified, including schistosome and fasciolid competent snail species. We report for the first time the invasive exotic snail Tarebia granifera in Zimbabwe, which was highly abundant, mainly in Chiredzi, occurring at 29 out of 35 sites. Shedding experiments on 1303 snails revealed a 2.24% infection rate, with 15 trematode species identified through molecular genotyping. Five species were exclusive to Chiredzi: Bolbophorus sp., Schistosoma mansoni, Schistosoma mattheei, Calicophoron sp., and Uvulifer sp. Eight were exclusive to Wedza, including Trichobilharzia sp., Stephanoprora amurensis, Spirorchid sp., and Echinostoma sp. as well as an unidentified species of the Plagiorchioidea superfamily. One species, Tylodelphys mashonensis, was common to both regions. The RD-PCR screening of 976 non-shedding snails indicated a 35.7% trematode infection rate, including the presence of schistosomes (1.1%) Fasciola nyanzae (0.6%). In Chiredzi, Radix natalensis had the highest trematode infection prevalence (33.3%), while in Wedza, R. natalensis (55.4%) and Bulinus tropicus (53.2%) had the highest infection prevalence. CONCLUSIONS: Our xenomonitoring approach unveiled 15 trematode species, including nine new records in Zimbabwe. Schistosoma mansoni persists in the study region despite six mass deworming rounds. The high snail and parasite diversity, including the presence of exotic snail species that can impact endemic species and biomedically important trematodes, underscores the need for increased monitoring.

The Covid-19 Pandemic: Limited Water Access and the Precarity of Women Fishers at Lake Kariba, Zimbabwe.

Man-made reservoirs are constructed to meet certain purposes and Lake Kariba, Zimbabwe, was designed for hydroelectric power generation. However, it has developed other multiple uses, and the growth of fisheries on the lake has had a significant impact on the livelihoods of local communities. The declaration of Covid-19 as a pandemic in Zimbabwe in March 2020 was quickly followed by the imposition of national lockdowns with varying levels of severity up to the present day. This was done to curtail the spread of the disease, meanwhile enhancing the nation's capacity in terms of acquiring testing kits, constructing more admission and quarantine centres as well as educating the people about ways to keep safe. In response to the calls by the government to monitor the movement of people and compliance of the lockdown rules, the Zimbabwe National Parks and Wildlife Management Authority (ZNPWMA), the governing body of the Lake Kariba fisheries, imposed rules that have significantly impacted the fishing communities at Lake Kariba. Both gillnet fishers and rod and line fishers have been impacted, but our focus here is on women rod and line fishers. Using the precarious livelihoods conceptual frameworks, we show how the changes in water management during the Covid-19 pandemic lockdowns has generated high levels of precariousness on the livelihoods of women at Kariba. We define precariousness as the condition of uncertainties brought to the women fishers by changes in water restrictions. The precarity of women was induced by several factors. For instance, the women fishers reported that restrictions to accessing fish in areas with high catches impacted them. They are also now obliged to pay exorbitant fishing fees in a way to discourage them to fish; they were frequently chased away from the Lake by ZNPWMA officers; they had limited amount of time to fish due to curfews; and failure to comply results in heavy fines imposed on them among other challenges. We show how these challenges interact with the current Zimbabwe socio-economic crisis to worsen the precariousness and vulnerability of women fishers at Lake Kariba. Data presented in this manuscript are based on participant observation and interviews with women fishers at Lake Kariba.

Land use effects on water quality, habitat, and macroinvertebrate and diatom communities in African highland streams.

Anthropogenic activities have increasingly subjected freshwater ecosystems globally to various pressures. Increasing land use activities have been highly linked to deteriorating freshwater ecosystems and dwindling biodiversity. For sound management and conservation policies to be implemented, relations between land use, environmental, and biotic components need to be widely documented. To evaluate the impacts of land use on biotic components, this study analyzed the diatom and macroinvertebrate community composition of the Eastern Highlands (Zimbabwe) streams to assess the main spatial diatom and macroinvertebrate community variances and how environmental variables and spatial factors influence community composition. Diatom and macroinvertebrate sampling was done in 16 streams in protected areas (national parks) and impacted sites (timber plantation and communal areas). Water (pH, phosphorus, and ammonium) and sediment (nitrogen, phosphorus, calcium, magnesium, manganese, and zinc) and habitat (substrate embeddedness, and habitat) variables differed significantly with land use. Principal Component Analysis (PCA) showed that the protected area had the best water quality, particularly marked by high pH levels and low phosphorus concentrations among environment types. Heavy metals were high in the communal areas, although mercury was higher in the national park. Significant differences were observed in diatom metrics, specifically dominance and evenness, with no significant differences observed in macroinvertebrate metrics across land uses. Diatoms differed in terms of composition in response to land use. Results provide an important scientific reference for land use optimization and guidance for the formulation of policies to protect freshwater resources in African Highland streams. Management and conservation initiatives in the Eastern Highlands are further recommended as this study detected high levels of mercury in the protected area, implying high levels of illegal mining.

Correction: Plague in Zimbabwe from 1974 to 2018: A review article.

[This corrects the article DOI: 10.1371/journal.pntd.0007761.].

Genetic analysis of 27 Y-chromosomal STR loci in a Zimbabwean Shona ethnic group.

Buccal swabs from 200 unrelated Zimbabwean males were collected from voluntary participants located in Harare province. The 5-dye SureID® 27Y Human STR Identification Kit was used to perform multiplex polymerase chain reactions (PCR) and generate Y-chromosomal DNA profiles. This kit targets markers DYS456, DYS576, DYS570, DYS481, DYF387S1, DYS627, DYS393, DYS391, DYS390, DYS635, DYS449, DYS533, DYS438, DYS389I, DYS448, DYS389II, DYS19, GATA_H4, DYS518, DYS458, DYS460, DYS437, DYS439, DYS392, and DYS385, similar to the Yfiler® Plus Amplification Kit. A total of 161 haplotypes were generated with the PowerPlex® Y system, whereas 159 complete haplotypes were generated for the Yfiler® Plus system. Haplotype Discrimination Capacity (DC) with the Yfiler® Plus system was determined to be 0.9686, while the Genetic Diversity (GD) of the targeted loci ranged from 0.03748 at DYS392 to 0.867239 at DYS449. One haplotype contained the triallelic pattern 37, 38, and 39 at DYS387S1. In addition, marker DYS387S1 and marker DYS385 had 13 counts of microvariant alleles overall, while 9 null allele counts were noted at marker DYS448. Genetic distances between our population data and 22 other data sets from African countries and people of African descent were estimated and results showed significant genetic variation.

Plague in Zimbabwe from 1974 to 2018: A review article.

Plague is a zoonotic disease caused by the bacterium Yersinia pestis and is transmitted through the bites of infected rodent fleas. Plague is well known for causing 3 major human pandemics that have killed millions of people since 541 A.D. The aim of this Review is to provide an overview of the epidemiology and ecology of plague in Zimbabwe with special emphasis on its introduction, its potential reservoirs and vectors, and possible causes of its persistence and cyclic outbreaks. To achieve this, we carried out a search and document reported plague outbreaks in Zimbabwe. In the country, human plague cases have been reported in Hwange, Nkayi, and Lupane since 1974. The highest number of cases occurred in 1994 in the Nkayi district of Matabeleland North Province with a total of 329 confirmed human cases and 28 deaths. Plague is encountered in 2 different foci in the country, sylvatic and rural. Risk factors for contracting plague in the country include man-to-rodent contact, cultivation, hunting, cattle herding, handling of infected materials, camping in forests, and anthropic invasion of new areas. Plague is now enzootic in Zimbabwe, and the most recent case was reported in 2012, hence its effective control requires up-to-date information on the epidemiology and ecology of the disease. This can be achieved through continuous monitoring and awareness programs in plague-prone areas.

A Comparative Evaluation of Carcass Quality, Nutritional Value, and Consumer Preference of Oreochromis niloticus from Two Impoundments with Different Pollution Levels in Zimbabwe.

The objective of the study was to determine the quality and consumer preferences of Nile tilapia (Oreochromis niloticus) from two water bodies with different pollution levels and trophic states. Water quality assessment of the two impoundments was carried out. Fish were sampled from hypereutrophic Lake Chivero and oligomesotrophic Lake Kariba for proximate analysis, carcass quality, and sensory evaluation. Conductivity, dissolved oxygen, transparency, ammonia, total phosphates, reactive phosphates, and chlorophyll a were significantly different (P<0.05). Fish from Lake Kariba had significantly higher condition factors and lower fillet yields, while fish of length 10-20 cm, from Lake Chivero had significantly more fat. Lake Chivero fish were darker, greener, and less red while Lake Kariba fish were lighter, less green, and less red. Raw fish from Lake Kariba were significantly firmer, were less green and redder, had a stronger typical fish odour, and were more acceptable than Lake Chivero fish. Lake Chivero fish had a stronger foreign fish odour than their counterparts. No statistical differences were observed on fillet cooking losses, cooked fish sensory parameters, and acceptability. The fish could, however, not be safe due to possibility of toxins in water and feed (algae) which may bioaccumulate and ultimately affect other attributes of fish quality.

Escherichia coli Contamination across Multiple Environmental Compartments (Soil, Hands, Drinking Water, and Handwashing Water) in Urban Harare: Correlations and Risk Factors.

Escherichia coli pathotypes (i.e., enteropathogenic and enterotoxigenic) have been identified among the pathogens most responsible for moderate-to-severe diarrhea in low- and middle-income countries (LMICs). Pathogenic E. coli are transmitted from infected human or animal feces to new susceptible hosts via environmental reservoirs such as hands, water, and soil. Commensal E. coli, which includes nonpathogenic E. coli strains, are widely used as fecal bacteria indicator, with their presence associated with increased likelihood of enteric pathogens and/or diarrheal disease. In this study, we investigated E. coli contamination in environmental reservoirs within households (N = 142) in high-population density communities of Harare, Zimbabwe. We further assessed the interconnectedness of the environmental compartments by investigating associations between, and household-level risk factors for, E. coli contamination. From the data we collected, the source and risk factors for E. coli contamination are not readily apparent. One notable exception is the presence of running tap water on the household plot, which is associated with significantly less E. coli contamination of drinking water, handwashing water, and hands after handwashing. In addition, E. coli levels on hands after washing are significantly associated with handwashing water contamination, hand contamination before washing, and diarrhea incidence. Finally, we observed that animal ownership increases E. coli contamination in soil, and E. coli in soil are correlated with contamination on hands before washing. This study highlights the complexity of E. coli contamination in household environments within LMICs. More, larger, studies are needed to better identify sources and exposure pathways of E. coli-and enteric pathogens generally-to identify effective interventions.

Impact of irrigation based sugarcane cultivation on the Chiredzi and Runde Rivers quality, Zimbabwe.

Agriculture is vital in sustaining human livelihoods. However, agriculture as it is currently practiced, is contributing to the degradation of freshwater ecosystems globally. We investigated impacts of irrigation return flows from sugarcane farming on water quality and health status of the Chiredzi and Runde Rivers, a biodiversity hotspot region in south-eastern Lowveld of Zimbabwe. The water quality at inlets from the crop field into the wetland system; wetland outlets into the river systems; and river sites upstream and downstream of wetland outlets were monitored during the dry and wet seasons. The wetland system formed naturally from excessive drainage from the cane fields but its purifying capacity was unknown to date. An assessment of the water physical-chemical variables (at all sites) and macroinvertebrate communities (at river sites only) was carried out. Results showed that the wetland was deficient in its purifying capacity as it was already saturated by salts and nutrients from high irrigation return flow loads. A significant seasonal variation was observed for conductivity, reactive phosphorus (RP), pH and total phosphorus (TP) concentrations among the inlets to the wetland whereas among the river sites significant seasonal differences were observed for ammonium, dissolved oxygen, nitrate, RP, pH, TP and turbidity concentrations during the dry season. From the macroinvertebrate community data the impact of the irrigation return flows on the river system was apparent, as the good water quality sites were characterised by a high diversity of pollution sensitive macroinvertebrate taxa, while the irrigation impacted sites were characterised and dominated by pollution tolerant taxa. High ion concentration (conductivity and salinity) and pH were found to be important in structuring macroinvertebrate communities as determined using multivariate analysis in the river system. In conclusion, the river water quality was significantly impacted by irrigation return flows and this greatly reduced the ecological health as highlighted by low macroinvertebrate diversity and increases in physical-chemical variables.

Handwashing, but how? Microbial effectiveness of existing handwashing practices in high-density suburbs of Harare, Zimbabwe.

BACKGROUND: Consistent domestic hand hygiene can reduce diarrhea-related morbidity and mortality and the spread of other communicable diseases. However, it remains uncertain which technique of handwashing is most effective and practicable during everyday life. The goal of this study is to determine how the handwashing technique, as performed in the daily life by the participants of this case study in Harare, Zimbabwe, influences microbial handwashing effectiveness. METHODS: Handwashing technique of 173 primary caregivers was observed in their homes and hand rinse samples were collected before and after handwashing. Samples were analyzed for Escherichia coli and total coliform concentrations. Generalized linear models were used to predict fecal hand contamination after washing from observed handwashing technique. RESULTS: Cleaning under fingernails, scrubbing the fingertips, using soap, and drying hands through rubbing on clothes or a clean towel statistically significantly reduced E coli contamination of hands after washing. Tap use, scrubbing fingertips, and rubbing hands on clothes to dry them statistically significantly reduced total coliform contamination. CONCLUSIONS: Recommendations for effective and practicable domestic handwashing in Harare, Zimbabwe, should include performing specific handscrubbing steps (ie, cleaning under the fingernails and rubbing the fingertips), and soap and tap use. This calls for further research to develop behavior change interventions that explicitly promote effective handwashing technique at critical times.