Browsing by Author "Gong, Yun"

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Association Between Aflatoxin Exposure and Haemoglobin, Zinc, and Vitamin A, C, and E Levels/Status: A Systematic Review
(MDPI, 2025-02-28) Mshanga, Naelijwa; Moore, Sally; Kassim, Neema; Martin, Haikael; Auma, Carolyn; Gong, Yun
Background: Aflatoxin, produced by Aspergillus flavus and Aspergillus parasiticus fungi, contaminates a broad range of crops such as maize, nuts, and cotton. Aflatoxin exposure causes growth failure, immune suppression, and liver cancer. While several systematic reviews have assessed the link between aflatoxin exposure and growth development in humans, there is a lack of reviews on the associations between aflatoxin exposure and micronutrient levels/status. This review addresses that gap by compiling studies on the association between aflatoxin exposure and micronutrient levels/status in humans. Methods: A comprehensive search of the SCOPUS, PUBMED, EMBASE, and Web of Science databases was conducted, focusing on studies published between 2003 and 2023. Only English-language studies using urine, blood, serum, or plasma biomarkers were included to assess the exposure and outcomes. The risk of bias in these studies was evaluated using the Academy of Nutrition and Dietetics Quality Criteria for human studies. Results: Ten observational studies were included in the systematic review, which collectively reported the association between aflatoxin exposure and haemoglobin, zinc, and vitamin A, E, and C levels. This review suggests that aflatoxin exposure is associated with micronutrient deficiencies, such as anaemia (low haemoglobin levels (<11 g/dL)) in pregnant women and vitamin A deficiency in adults and children. Conclusions: This review highlights the link between aflatoxin exposure and micronutrient deficiencies, emphasizing the need for aflatoxin mitigation within micronutrient interventions. Future studies should focus on longitudinal and interventional research to establish causal relationships and assess the effectiveness of mitigation strategies. Additionally, further research is needed to explore the interaction between aflatoxin exposure and other potential confounding factors such as dietary patterns, socioeconomic status, and genetic predisposition.
Estimating the risk of aflatoxin-induced liver cancer in Tanzania based on biomarker data.
(PLOS ONE, 2021-03-11) Kimanya, Martin; Routledge, Michael; Ezekiel, Chibundu; Shirima, Candida; Gong, Yun; Mpolya, Emmanuel
Evidence about the magnitude of the aflatoxin menace can help policy makers appreciate the importance of the problem and strengthen policies to support aflatoxin mitigation measures. In this study, we estimated aflatoxin-induced liver cancer risk in 2016 for Tanzania and used the information to estimate the health burden due to the aflatoxin exposure in the country. The burden of aflatoxin-induced liver cancer was assessed based on available aflatoxin biomarker data from a previous epidemiology study, hepatitis B virus infection prevalence and population size of Tanzania in 2016. The health burden due to aflatoxin-induced liver cancer was estimated using disability adjusted life years (DALYs). The aflatoxin exposures ranged from 15.0-10,926.0 ng/kg bw/day (median, 105.5 ng/kg bw/day). We estimated that in 2016 there were about 1,480 (2.95 per 100,000 persons) new cases of aflatoxin-induced liver cancer in Tanzania and assumed all of them would die within a year. These morbidity and mortality rates led to a total loss of about 56,247.63 DALYs. These results show, quantitatively, the cases of liver cancer and related deaths that could be avoided, and the healthy life years that could be saved, annually, by strengthening measures to control aflatoxin contamination in Tanzania.
Evaluation of a point-of-use device used for autoantibody analysis and its potential for following microcystin leucine-arginine exposure
(Frontiers, 2024-02-09) Ma, Hui; Loscher, Christine; Parle-McDermott, Anne; Fitzgerald, Jenny; Meneely, Julie; Elliott, Christopher; Welten, Richard; Mchau, Geofrey; Makule, Edna; Machunda, Revocatus; Gong, Yun; Kimanya, Martin; Crawley, Aoife; Maguire, Ivan; Murphy, Caroline; Kennedy, Richard
Introduction: Globally, the need for measuring exposure to algal toxins has become urgent due to ever-increasing reports of contamination in sea and freshwater, in shellfish and fish stocks and in aerosols. Methods: To address this issue, we evaluated the potential of determining autoantibodies to a panel of biomarkers known to be elevated following exposure to the hepatotoxin microcystin leucine-arginine. The presence of autoantibodies, specific to four selected stress-response, metabolomic and chaperone biomarkers, namely, Heat shock protein 1, Triosephosphate isomerase, Peroxiredoxin 1 and Peroxiredoxin 2 was employed in screening 371 serum samples from microcystin-exposed individuals in Tanzania. In addition, the capacity of the LightDeck fluorescence-based detector, a point-of-use device, to monitor these autoantibody responses in comparison to enzyme-linked immunosorbent assay was evaluated. Results: By using the determination of autoantibodies to this novel panel of biomarkers an altered response was observed following microcystin exposure, with levels generally upregulated. The presence of elevated levels of microcystin leucine-arginine in water, as well as in food sources in Tanzania, may potentially have significant health effects on the population. Discussion: This novel biomarker panel may have potential for the detection of microcystin leucine-arginine exposure as well as various microcystin exposure-associated cancers (e.g., hepatocellular cancer and colorectal cancer). In addition, the utilisation of the LightDeck point-of-use device proved successful for the rapid analysis of this biomarker panel.
Harmful algal bloom and associated health risks among users of Lake Victoria freshwater: Ukerewe Island, Tanzania
(J Water Health, 2019-07-24) Mchau, Geofrey; Makule, Edna; Machunda, Revocatus; Gong, Yun; Kimanya, Martin
There is a global concern regarding the occurrences of harmful algal blooms (HABs) and their effects on human health. Lake Victoria (LV) has been reported to face eutrophication challenges, resulting in an increase of bloom-forming cyanobacteria. This study is aimed at understanding the association of HABs and health risks at Ukerewe Island. A cross-sectional study conducted on 432 study subjects and water samples for cyanobacteria species identification were collected at LV shores. The results reveal that concentrations of cyanobacteria cells are beyond (WHO) acceptable limits; species of Microcystis aeruginosa range from 90,361.63 to 3,032.031.65 cells/mL and Anabaena spp. range from 13,310.00 to 4,814,702 cells/mL. Water usage indicates that 31% use lake water, 53% well water and 16% treated supplied pipe water. Vomiting and throat irritation was highly reported by lake water users as compared to wells and pipe water (P < 0.001). Gastrointestinal illness (GI) was significantly elevated among lake water users as compared to pipe and well water users (P < 0.001). Visible blooms in lake water were associated with GI, skin irritation and vomiting as compared to water without visible blooms (P < 0.001). The concentration of cyanobacteria blooms poses greater risks when water is used without treatment.
Phycocyanin as a proxy for algal blooms in surface waters: case study of Ukerewe Island, Tanzania
(IWA Publishing, 2019-01-08) Mchau, Geofrey; Makule, Edna; Machunda, Revocatus; Gong, Yun; Kimanya, Martin
Knowledge of the parameters that contribute to water body eutrophication is essential for proper monitoring and management of water quality for human consumption. This study assessed water quality parameters in relation to phycocyanin (PC) as a proxy indicator for harmful algal blooms (HABs). Samples were collected from 23 water sources – lakes, wells, springs and boreholes – in selected villages, for six months. Parameters measured included temperature, pH, redox potential, dissolved oxygen, electrical conductivity, total dissolved solids, nitrate nitrogen, nitrite nitrogen, phosphorus, reactive phosphate and total chlorophyll, which were related to (PC) occurrence. The PC concentration detected in Lake Victoria ranged from 5 to 58.4 μg/l above the WHO alert level and exceeded that in other water sources by almost 30 μg/l (P < 0.001). Univariate relationship between water quality parameters and PC indicates association with temperature, redox potential, total chlorophyll, nitrate nitrogen, nitrite nitrogen, phosphate and reactive phosphorus (P < 0.001). The multivariate model indicates that redox potential, nitrate nitrogen and phosphorus are significant statistically (P < 0.05). A predictive model indicates that nitrate nitrogen and reactive phosphorus contribute significantly to PC occurrence whereby unit (1 mg/l) increases in these parameters increase PC by 9.55 and 4.38 μg/l (P < 0.05) respectively. This study demonstrates that water quality parameters can be used to predict increases in PC and hence as a proxy for HABs. It remains important to be able to classify algal blooms, to understand which species are present and their potential cyanotoxin production.