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Map of the world indicating the tropical and subtropical zones.

Map of the world indicating the tropical and subtropical zones.

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A growing number of people undertake international travel, and yet faster growth of such travel is expected in the tropics. Information on the hazards presented by pool and hot spring waters in tropical countries is very limited. This review aims to collate available information on pool water quality, alongside data on cases and outbreaks associate...

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... review endeavours to focus on infections transmitted by pool waters and caused by pathogens that, with the exception of Cryptosporidium spp. [18], are unusual in the moderate climates and common in the tropical and subtropical countries, including southern regions of Japan and North Australia, as shown in Figure 1. ...

Citations

... Much of our knowledge of past and current recreational water risks relates to marine and coastal waters (Fewtrell and Kay 2015;Leonard et al. 2018;Russo et al. 2020;Wu et al. 2020;King et al. 2015), treated freshwater bodies such as swimming pools, hot tubs, or other indoor facilities (Leoni 2019;Leoni et al. 2018;Bonadonna and La Rosa 2019;Momas et al. 1993;Mavridou et al. 2018), and untreated or ambient freshwaters (McDougall et al. 2020;Bourque and Vinetz 2018;Ayi 2015;Boehm et al. 2018;Diallo et al. 2008;Ferley et al. 1989;Gorham and Lee 2014;Jang et al. 2019;Vergara et al. 2016). Recent literature has focussed on the importance of freshwaterbased recreation in urban areas. ...
Article
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Recreational use of natural freshwater bodies poses a risk to human health, although the risks associated with different types of exposure in freshwater are not clear. A systematic review was carried out to identify the risks of adverse health outcomes among individuals exposed through primary contact recreation compared to minimal contact recreation in different types of freshwater bodies. Among 5858 potentially relevant titles and abstracts, 35 were eligible for final inclusion. We included studies that reported the type of freshwater exposure and health outcomes, were peer-reviewed, and had full-text articles available in English. Across all studies, general gastrointestinal illness was the most commonly reported (77.1%), followed by skin (37.1%) and ear-related infection (34.3%), respiratory illness (31.4%), and eye-related illness (25.7%). Most studies reported adverse health outcomes from primary contact recreation (85.7%) in comparison to secondary contact activities (17.1%) and no-contact recreation (2.9%). More than half of the included studies (54.3%) focussed on lakes. The continued focus on primary contact recreation in lakes is a concern, given the growing global trend in secondary and non-contact recreation associated with urban wetlands. A better understanding of risks associated with recreational contact with freshwater in these settings is needed.
... Hot spring-associated Legionella outbreaks have been reported in previous studies in many countries (Ghilamicael et al., 2018;Hsu et al., 2006;Kuroki et al., 2009;Marston et al., 1997). Similarly, Chlamydiae, which is commonly associated with clinical infections such as trachoma, is frequently found in recreational hot spring pools (Mavridou et al., 2018). Hot springs are open for bathing and spa activities in Taiwan (Hsu et al., 2006), and the HG Creek has been characterized as a moderately polluted water body based on its RPI value (Table S2). ...
Article
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The microbial characteristics of water bodies located in the outflow of hot springs may affect the water quality parameters of the associated river ecosystem. Using 16S rRNA amplicon sequencing, we investigated the bacterial diversity and functional profiles of the Huang Gang (HG) Creek, located in the trace metal-rich, acid-sulfate thermal springs zone of the Tatun Volcano Group (TVG). Biofilms and water samples were collected from the upstream, midstream, and geothermal valleys and downstream of the creek. The results showed that the biofilm and water samples had distinct bacterial diversity and abundance profiles. Acidophilic sulfur-oxidizing bacteria were found to be more abundant in water samples, whereas aquatic photosynthetic bacterial communities were dominant in biofilms. The water samples were contaminated with Legionella and Chlamydiae, which could contaminate the nearby river and cause clinical infections in humans. The upstream samples were highly unique and displayed higher diversity than the other sites. Moderate thermo-acidophiles were dominant in the upstream and midstream regions, whereas the geothermal valley and downstream samples were abundant in thermo-acidophiles. In addition, functional profiling revealed higher expression of sulfur, arsenic, and iron-related functions in water and lead-related functions in the biofilms of the creek. As described in previous studies, the hydrochemical properties of the HG Creek were influenced by the TVG hot springs. Our findings indicated that the hydrochemical properties of the HG Creek were highly correlated with the bacterial diversity and functional potential of running water as compared to biofilms.
... This is likely since people living in tropical areas are exposed to more sunlight than those living in subtropical regions [2,5]. Among the South Asian countries, Pakistan and Afghanistan are situated in a subtropical area, while Sri Lanka is situated in a tropical area [72]. In our study, we also found that Pakistan and Afghanistan had the highest prevalence of hypovitaminosis D in South Asia; 94% (nation-wide average of serum vitamin D 11.78 ng/mL) and 96% (nation-wide average of serum vitamin D 5 ng/mL), respectively. ...
Article
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Background Vitamin D is vital for the growth and development of children. While deficiency and/or insufficiency of vitamin D among South Asian children are frequently reported in the literature, the lack of a meta-analysis has left its true extent poorly characterized. In this study, we aimed to conduct a systematic review and perform meta-analyses of the prevalence of hypovitaminosis D among the children of the South Asian countries. Methods Two major electronic search engines (PubMed and Scopus) and one database (Google scholar) were used; original studies, conducted among South Asian children and adolescents and published between 1 January 2001 and 31 December 2019. A random-effect meta-analysis was also performed to calculate the pooled prevalence of hypovitaminosis D followed by subgroup analyses for countries and age groups. Results After applying inclusion and exclusion criteria, a total of 41 studies with a total population size of 18,233 were finally selected. The overall prevalence of hypovitaminosis D was 61% [95% CI: 46% to 71%] with highly significant heterogeneity (I² = 99.72%; p < 0.0001). The average level of serum vitamin D ranged from 5 ng/mL to 34 ng/mL, with a weighted mean of 19.15 ng/mL (weighted standard deviation 11.59 ng/mL). Country-wise analysis showed that hypovitaminosis D in Afghanistan was the highest [96.2%; 95% CI: 91% to 99%], followed by Pakistan [94%; 95% CI: 90% to 96%], India [64%; 95% CI: 46% to 79%], Bangladesh [35.48%; 95% CI: 32% to 39%], Nepal [35%; 95% CI: 1% to 83%], and Sri Lanka [25%; 95% CI: 16% to 36%]. Age group analyses revealed that hypovitaminosis D was most prevalent among neonates [85%; 95% CI: 76% to 91%], followed by school-going children [57%; 95% CI: 33% to 80%], and preschool children [55%; 95% CI: 35% to 75%]. Conclusion This study generates quantitative evidence and specific extent of hypovitaminosis D in the South Asian countries as a public health concern. Being the first systematic review for this region, results from this study will create awareness and will facilitate adopting mitigation strategies by the policymakers and the governments to address this problem.
... The route of Salmonella infection in our patient is unclear, although infectious agents have been reported to threaten the health of pool users in tropical countries [22][23][24]. Since his family members did not show gastrointestinal symptoms during and after their trip, we speculate that he may have ingested contaminated water from the pool in the hotel. ...
Article
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Background Renal abscesses are relatively uncommon in children, and usually due to Gram-negative rods or Staphylococcus aureus , whereas abscesses caused by Salmonella are very rare. Case presentation We present the case of a previously healthy 10-year-old boy who had a renal abscess due to Salmonella bareilly. He responded well to treatment with antibiotics, and computed tomography (CT)-guided drainage of the abscess. His blood, urine and abscess aspirate cultures were sterile, but a broad-range 16S rDNA polymerase chain reaction (PCR) assay of the aspirate followed by analysis of four Salmonella genes ( fliC , fliD , sopE2 , and spaO ) identified S . bareilly as the causative agent. Conclusion To the best of our knowledge, this is the first report of renal abscess caused by S. bareilly.
... The results indicate the presence of various chemical and infectious agents in these pools, which may under certain circumstances pose a serious health threat to those coming in contact with the pools' water. Since the indoor pool attracts people all year round, the safety and hygiene of the water are of particular importance [5,21,[25][26][27][28][29][30][31]. We used Palin UDP kit (USA) to measure residual chlorine level in this study. ...
Article
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Introduction. Considering the existence of both parasitic and fungal pathogens in the indoor public swimming pools and non-utilization of suitable filtration and disinfection systems in these places, this research aimed to determine the relationship between the indoor public swimming pools and possible pollution with parasitic and fungal agents, as well as physical and chemical characteristics of these pools and compare the results with national standards. Methods. In this study, 11 active indoor swimming pools of Zahedan city were sampled, using plastic pump techniques, from the middle of winter to the late summer season. A total of 88 water samples (eight water samples from each pool) were examined to determine the residual chlorine, contamination with parasitic and fungal agents, using culture media and slide culture techniques. Results were analyzed with SPSS software (V16) and, Microsoft Excel (V2010). Results. The findings revealed fungal contamination with Cladosporium, Penicillium, Aspergillus flavus and Aspergillus fumigatus, etc. and the physicochemical factors comply with the minimum standards, which indicates the need for continuous monitoring and control of water filtration and disinfection of water in the pools. Conclusion. The results show reasonable derangement of physicochemical and microbial factors of the evaluated pools. Efforts shall be made by the concerned authorities to provide health education to users, quality water at the pools and to maintain the safety and quality of the water through proper and adequate chlorination.
... Pakistan is situated in a subtropical region where there is relatively low sunlight availability compared to tropical regions. The national boundaries of Bangladesh and India both share tropical and subtropical regions in their national map (60) . Our hypothesis can be bolstered by the fact that a high prevalence of vitamin D insufficiency was also observed in countries like Iran (56 %) and China (70 %) (using < 20 ng/ml cut-off), which share similar geographical locations on their national map (55,61) . ...
... Additionally, this hypothesis is also corroborated by intra-country study reports. For instance, geolocation hinted that northern part of India is placed in sub-tropical zone, whereas southern section is in tropical zone (60) . Study reports suggested Fig. 3. Forest plot represents prevalence of vitamin D insufficiency in accordance with study settings (community-based v. hospital-based). ...
... According to the Fitzpatrick skin type, most Nepalese belong to lighter skin in comparison with Indian subcontinent women (63) . Despite Nepal being situated in a subtropical region (60) , this lighter skin complexion could be an important factor behind the lowest observed prevalence of vitamin D insufficiency, in comparison to rest of the Indian sub-continent. Hence, we hypothesise that the disparity of skin complexion among SA population might be a potential confounding factor for the heterogeneity of serum vitamin D in SA. ...
Article
Insufficiency of vitamin D, during pregnancy, is a common cause of various pregnancy-related complications. Despite such insufficiency being frequently reported among South Asian pregnant women, the absence of systematic review and meta-analysis renders the true extent of this problem poorly characterized. In this systematic review, three main databases (PubMed, Scopus, and Google Scholar) were searched for original studies. We included original studies conducted on pregnant women who lived in South Asian countries and reported the prevalence of vitamin D insufficiency among the study participants. Twenty studies with a total of 7,804 participants from four South Asian countries finally met our selection criteria. Overall pooled prevalence of insufficiency was 65% [95 % CI: 51% to 78%] with a significant heterogeneity (I 2 = 99.37 %; p = 0.00). The average level of vitamin D ranged from 9 ng/mL to 24.86 ng/mL with a weighted mean of 16.37 ng/mL (weighted standard deviation 7.13 ng/mL). The highest prevalence of insufficiency was found in Pakistan (76%) followed by India (67%), Bangladesh (64%), and Nepal (14%). Results obtained in this study suggest that vitamin D insufficiency is highly prevalent among South Asian pregnant women. Being the first systematic review in this region, findings from this study will help in future studies and strengthen the evidence for policymakers to develop effective mitigation strategies.
... Vitamin D is synthesized naturally in the human body when UV-B from sunlight penetrates our skin and initiates the physiological processes of vitamin D synthesis [1,3]. Pakistan is located in a sub-tropical region where sunlight availability is relatively low [98]. However, Bangladesh and India both share tropical and subtropical regions in their national map. ...
... According to the Fitzpatrick scale, most of the Nepalese have lighter skin in comparison to population of the sub-continent, who tend to have a darker skin complexion [106]. Though Nepal is located in a subtropical region [98], because of skin color, Nepalese might need less sunlight exposure in comparison to sub-tropical people for the production of similar level of vitamin D. Therefore, the variation of skin complexion could be a potential determinant of the observed variability of vitamin D deficiency among the SA countries. ...
Article
Full-text available
Background Vitamin-D deficiency is linked to a wide range of chronic and infectious diseases. Body of literature suggested that the prevalence of this deficiency can have geographical variation. Although vitamin D deficiency is frequently reported in the South Asian population, the scarcity of systematic reviews and meta-analysis means the true extent of the disease and the underlying factors causing it are poorly characterized. Methods A systematic search was performed using two databases (PubMed and Scopus) and one search engine (Google Scholar) for original studies on the South Asian population (published from January 1, 2001, to December 31, 2019). Following the search, a random effect meta-analysis was performed to calculate population-level weighted average, the pooled prevalence of deficiency, and heterogeneity of vitamin D among different countries and genders; in addition to South Asia as a whole. Results Our study, based on our selection criteria was narrowed down to a total of 44,717 participants; which spanned over 65 studies from five South Asian countries. Overall, the pooled prevalence of deficiency was 68% [95% CI: 64 to 72%] with significant heterogeneity (I² = 98%; p = 0.00). The average level of vitamin D ranged from 4.7 to 32 ng/mL, with a weighted mean of 19.15 ng/mL (weighted standard deviation 11.59 ng/mL). The highest prevalence of vitamin D deficiency was found in Pakistan (73%;95% CI: 63 to 83%) followed by Bangladesh (67%; 95% CI: 50 to 83%), India (67%; 95% CI: 61 to 73%), Nepal (57%; 95% CI: 53 to 60%) and Sri Lanka (48%; 95% CI: 41 to 55%), respectively. This finding indicated a high degree of heterogeneity among the population. (I² = 98.76%), Furthermore, a gender-wise analysis suggested that in South Asia, the prevalence of vitamin D deficiency was higher in females than males. Conclusion Our findings reveal highly prevalent and variable vitamin D deficiency among the adults of different South Asian countries. Findings from this review would be helpful to generate hypotheses and explore the factors affecting the inter-country variability, alongside strengthening evidence for governments to prioritize mitigation strategies in this region.
... Remote sensing-based assessment of PM 2.5 concentration is conducted for 10 tropical and subtropical countries including Brazil, India, Iran, Kenya, Malaysia, Mexico, Pakistan, Peru, Sri Lanka and Thailand. A study by Mavridou et al. (2018) was used as a reference in identifying tropical and subtropical countries. Availability of data concerning satellite image, lockdown duration and national health information in addition to the Global Burden of Diseases study (GBD, 2019) was referred to ensure that selected countries covered a broader range of health risk rates (high to low) as an effect of exposure to ambient particulate matter. ...
Article
Full-text available
A novel coronavirus disease (COVID-19) continues to challenge the whole world. The disease has claimed many fatalities as it has transcended from one country to another since it was first discovered in China in late 2019. To prevent further morbidity and mortality associated with COVID-19, most of the countries initiated a countrywide lockdown. While physical distancing and lockdowns helped in curbing the spread of this novel coronavirus, it led to massive economic losses for the nations. Positive impacts have been observed due to lockdown in terms of improved air quality of the nations. In the current research, ten tropical and subtropical countries have been analysed from multiple angles, including air pollution, assessment and valuation of health impacts and economic loss of countries during COVID-19 lockdown. Countries include Brazil, India, Iran, Kenya, Malaysia, Mexico, Pakistan, Peru, Sri Lanka, and Thailand. Validated Simplified Aerosol Retrieval Algorithm (SARA) binning model is used on data collated from moderate resolution imaging spectroradiometer (MODIS) for particulate matters with a diameter of less than 2.5 μm (PM2.5) for all the countries for the month of January to May 2019 and 2020. The concentration results of PM2.5 show that air pollution has drastically reduced in 2020 post lockdown for all countries. The highest average concentration obtained by converting aerosol optical depth (AOD) for 2020 is observed for Thailand as 121.9 μg/m³ and the lowest for Mexico as 36.27 μg/m³. As air pollution is found to decrease in the April and May months of 2020 for nearly all countries, they are compared with respective previous year values for the same duration to calculate the reduced health burden due to lockdown. The present study estimates that cumulative about 100.9 Billion US$ are saved due to reduced air pollution externalities, which are about 25% of the cumulative economic loss of 435.9 Billion US$. Graphical abstract
... Of the 34 pool-associated cases reported worldwide from 1937 to 2018, only one such case has been reported since 1987, likely because of advancements in pool water management that includes disinfection standards [1]. Although swimming pool-associated PAM cases are rare, parasitic waterborne diseases including PAM have still been reported from pools, water parks, and hot springs in international tourist destinations [10][11][12]. This is most likely attributable to differences in standards for water quality among countries. ...
Article
Background In February 2020, a man returned to the United States after an 11-day trip to India and died of primary amebic meningoencephalitis (PAM), caused by nasal exposure to the free-living ameba Naegleria fowleri found in warm water. We identified potential exposures, confirmed etiology, and described molecular epidemiology of the infection. Methods We reviewed medical records to describe his clinical course and interviewed his family to determine water exposures. Genotyping was performed on the N. fowleri strain and compared with North American strains through repetitive non-polymorphic nuclear loci analysis to identify differences. We reviewed N. fowleri strains in the National Center for Biotechnology Information database (GenBank) to determine genotypes present in India. Results The patient became acutely encephalopathic 3 days after returning; the only known nasal water exposure was at an indoor swimming pool in India 5 days earlier. Cerebrospinal fluid (CSF) testing demonstrated neutrophil predominant pleocytosis and low glucose, but negative Gram stain and culture. CSF microscopy revealed trophozoites; N. fowleri was detected by real-time polymerase chain reaction. Classical genotyping confirmed genotype I, common in the United States and among Indian strains in GenBank. The North American N. fowleri strains and the patient’s strain varied at five non-polymorphic loci. Conclusion A man died from PAM after likely exposure at a vacation rental pool in India. We recommend including PAM in the differential diagnosis when CSF studies suggest bacterial meningitis, but Gram stain is negative. Genotyping can advance understanding of N. fowleri molecular epidemiology and support future investigations.
... This is likely since people living in tropical areas are exposed to more sunlight than those living in subtropical regions [2,5]. Among the South Asian countries, Pakistan and Afghanistan are situated in a subtropical area, while Sri Lanka is situated in a tropical area [72]. In our study, we also found that Pakistan and Afghanistan had the highest prevalence of hypovitaminosis D in South Asia; 94% (nation-wide average of serum vitamin D 11.78 ng/mL) and 96% (nation-wide average of serum vitamin D 5 ng/mL) respectively. ...
Preprint
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Background: Vitamin D is vital for the growth and development of children. While deficiency and/or insufficiency of vitamin D among South Asian children are frequently reported in the literature, the lack of a meta-analysis has left its true extent poorly characterized. In this study, we aimed to conduct a systematic review and perform meta-analyses of the prevalence of hypovitaminosis D among the children of the South Asian countries. Methods: Two major electronic search engines (PubMed and Scopus) and one database (Google scholar) were used; original studies, conducted among South Asian children and adolescents and published between 1st January 2001 and 31st December 2019. A random-effect meta-analysis was also performed to calculate the pooled prevalence of hypovitaminosis D followed by subgroup analyses for countries and age-groups. Results: After applying inclusion and exclusion criteria, a total of 41 studies with a total population size of 18,233 were finally selected. The overall prevalence of hypovitaminosis D was 61% [95% CI: 46% to 71%] with highly significant heterogeneity (I² = 99.72%; p = 0.00). The average level of serum vitamin D ranged from 5 ng/mL to 34 ng/mL, with a weighted mean of 19.15 ng/mL (weighted standard deviation 11.59 ng/mL). Country-wise analysis showed that hypovitaminosis D in Afghanistan was the highest [96.2%; 95% CI: 91% to 99%], followed by Pakistan [94%; 95% CI: 90% to 96%], India [64%; 95% CI: 46% to 79%], Bangladesh [35.48%; 95% CI: 32% to 39%], Nepal [35%; 95% CI: 1% to 83%.]and Sri Lanka [25%; 95% CI: 16% to 36%]. Age-group analyses revealed that hypovitaminosis D was most prevalent among neonates [85%; 95% CI: 76% to 91%], followed by school-going children [57%; 95% CI: 33% to 80%], and pre-school children [55%; 95% CI: 35% to 75%]. Conclusion: This study generates quantitative evidence and specific extent of hypovitaminosis D in the South Asian countries as a public health concern. Being the first systematic review for this region, results from this study will create awareness and will facilitate adopting mitigation strategies by the policymakers and the governments to address this problem.