Trends in waterborne protozoan pathogens in East and Southeast Asia from 2010 to 2020: distribution, biodiversity, risk factor hierarchy, and methods

This scoping review is primarily concerned with defining the distribution, biodiversity, risk factors, and methods involved in waterborne protozoan pathogens in East and Southeast Asia covering the period of 2010 to 2020. More importantly, this scoping review is concerned with drafting a risk factor hierarchy to organize the plethora of risk factors in a pragmatic approach that provides meaningful information for management and policy development from the level of domestic to international collaborative activities. Also, given the varying economic status of territories within East-Southeast Asia (Mostly developing) and the numerous methods for the detection of the target pathogens, this scoping review seeks to define the minimum requirements and considerations that will enable the detection of these pathogens even in resource-limited settings

The performance of tofu-whey as a liquid medium in the propagation of mycobacterium tuberculosis strain H37Rv

Objective: To investigate the performance of “tofu-whey liquid medium” for the propagation of Mycobacterium tuberculosis (MTB) strain H37Rv. Method: Two hundred micro liters (200μl) of 1 McFarland standard (1mg/ml-bacillary suspension) were inoculated into different batches of tofu-whey liquid medium. Each series contained three trials of test (tofu-whey liquid medium) and control media (Middlebrook 7H9 medium). Turbidity was measured within three weeks of inoculation using a nephelometer. The combinations of various tofu-whey liquid culture media were as follows; T1 (tofu-whey+ADC+glycerol+Potassium sulfate+Magnesium citrate+Sodium glutamate); T2 (tofu-whey + ADC + glycerol + Potassium sulfate + Magnesium citrate); T3 (tofu-whey + ADC + glycerol + Potassium sulfate); T4 (tofu-whey + ADC + glycerol); T5 (tofu-whey + ADC); and T6 (tofu-whey only). Results: In all test and control liquid culture media, the multiplication of M. tuberculosis was documented under light and fluorescence microscopy. Of various tofu-whey medium used, T1 demonstrated the most potential for MTB propagation. The increased turbidity reading represented by the value in “unit drop of % transmittance” was higher (25 scores) in the T1 tofu-whey medium, compared with the T6 tofu-whey medium (8 scores). The overall growth was significantly better in Middlebrook 7H9 culture media, although by the third day of incubation, the bacillary growth was superior in the T1 tofu-whey culture media. Sub-cultures in Lowenstein–Jensen (L–J) medium yielded between 87% (47 of 54) and 89% (48 of 54) recovery rate with between 7% and 13% contamination rate with coagulase-negative staphylococci. Conclusion: Tofu-whey media can be used as an economical alternative to Middlebrook 7H9 in resource-limited settings

Detection of potentially pathogenic free-living amoebae from the Caspian Sea and hospital ward dust of teaching hospitals in Guilan, Iran

Free-living amoebae (FLA) thrive in diverse environmental conditions. The present study aimed to define the FLA distribution from the Caspian Sea as well as from hospital ward dust from Guilan, Iran. Seawater (20) and hospital ward dust samples (100) were collected from May to June 2018. Seawater samples were vacuum filtered through a 0.45 mu m pore-size membrane. Dust was collected using sterile gauze, washed with sterile distilled water, with washings collected thereafter. Washings were similarly filtered as seawater samples. FLA from the filtered material was cultivated in non-nutrient agar. Molecular analysis was performed by PCR and sequencing using specific primers for Acanthamoeba, Naegleria, and Vermamoeba/Hartmanella. Culture and PCR returned 50 and 65% positivity, respectively, for seawater samples where sequencing revealed Acanthamoeba T2, T5 and T6 genotypes and A. palestinensis and A. lenticulata, as well as N. dobsoni and N. clarki. In addition, 30% amoebic growth and 16% PCR detection were observed from hospital ward dust samples where sequencing revealed Acanthamoeba T2, T4 and T11 genotypes and A. castellanii, A. palestinensis and A. stevensoni as well as N. clarki. For both seawater and dust samples, Acanthamoeba was the dominant isolate. The detection of potentially pathogenic FLA from seawater may pose a threat to the public, while the presence of the same in dust spells threats to both hospital staff and patients, in particular, immunocompromised individuals. Public education, awareness, improved sanitation and hygiene, and the crafting of diagnostic strategies for the early detection of FLA in humans are necessary for the mitigation and management of potential human infection cases

Reduction in total leukocytes in malaria patients compared to febrile controls: A systematic review and meta-analysis.

BackgroundLeukocyte alterations are a common hematological alteration among malaria patients.ObjectivesThis systematic review and meta-analysis aimed to provide data and evidence comparing alterations in total leukocyte counts in malaria patients compared to febrile/healthy subjects at baseline before treatment. A systematic review was conducted by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement for reporting systematic reviews and meta-analyses.Data sourcesWeb of Science (ISI), Scopus, and Medline.Study eligibility criteria, participants, and interventionsAll published articles reporting a total leukocyte count of patients infected with malaria, non-malaria (febrile or healthy group) at baseline before treatment before August 27, 2019, were retrieved, and data were extracted by two main reviewers independently.Study appraisal and synthesis methodsWe used a forest plot, heterogeneity test (Cochran's Q), and the degree of heterogeneity (I2) to test whether the included studies were heterogeneous. The quality of the included studies was determined by a quality assessment guide based on the quality assessment tool developed by the Newcastle-Ottawa Scale (NOS). Cochran's Q (Chi-square) and Moran's I2 were used to evaluate heterogeneity. Meta-regression using STATA software was conducted to find the source of heterogeneity. A funnel plot with Egger's test was used to examine the significance of publication bias among the included studies. The mean differences were estimated using a random-effects model.ResultsOut of the 2,261 articles screened, 29 articles were included in this systematic review and meta-analysis. The heterogeneity test indicated that there was heterogeneity among the included studies with no publication bias. The meta-analysis demonstrated that the total leukocyte count was significantly lower in patients with malaria (n = 4,619) than in those without malaria (n = 10,056) (Z = 4.0, P-value 0.05).LimitationsAs the specific diagnoses in the febrile groups were not reported in the included studies so that the results of the present study need to be carefully interpreted.Conclusions and implications of key findingsThis systematic review demonstrated that the total leukocyte count was affected by malarial infection at baseline despite the heterogeneity of the included studies. Future work must aim to understand the treatment-related total leukocyte reduction during follow-up or post-treatment outcomes in malaria-endemic settings

Severity and mortality of severe Plasmodium ovale infection: A systematic review and meta-analysis.

Plasmodium ovale can infect humans, causing malaria disease. We aimed to investigate the severity and mortality of severe P. ovale infection to increase the awareness of physicians regarding the prognosis of this severe disease and outcome-related deaths in countries in which this disease is endemic. Articles that were published in the PubMed, Scopus, and ISI Web of Science databases prior to January 5, 2020 and reported the prevalence of severe P. ovale infection were systematically searched and reviewed. Studies that mainly reported severe P. ovale infection according to the 2014 WHO criteria for the treatment of malaria were included. Two reviewers selected, identified, assessed, and extracted data from studies independently. The pooled prevalence of severe P. ovale mono-infections was estimated using the command "metaprop case population, random/fixed", which yielded the pooled estimate, 95% confidence interval (CI) and the I2 value, indicating the level of heterogeneity. Meta-analyses of the proportions were performed using a random-effects model to explore the different proportions of severity between patients with P. ovale and those with other Plasmodium species infections. Among the eight studies that were included and had a total of 1,365 ovale malaria cases, the pooled prevalence of severe P. ovale was 0.03 (95% CI = 0.03-0.05%, I2 = 54.4%). Jaundice (1.1%), severe anemia (0.88%), and pulmonary impairments (0.59%) were the most common severe complications found in patients infected with P. ovale. The meta-analysis demonstrated that a smaller proportion of patients with P. ovale than of patients with P. falciparum had severe infections (P-value = 0.01, OR = 0.36, 95% CI = 0.16-0.81, I2 = 72%). The mortality rate of severe P. ovale infections was 0.15% (2/1,365 cases). Although severe complications of P. ovale infections in patients are rare, it is very important to increase the awareness of physicians regarding the prognosis of severe P. ovale infections in patients, especially in a high-risk population

Multi-spatial contamination of environmental aquatic matrices withCryptosporidium: a climate, health, and regulatory framework for the Philippines

Background Cryptosporidiumis a waterborne global pathogen causing diarrhea primarily in infants and immunocompromised individuals. The Philippines is a tropical country susceptible to the influences of climate change and water crises. To date, the country has no existing epidemiologic data, regulation, or strategy for monitoringCryptosporidiumin freshwater systems. We, therefore, endeavored to provide evidence on the multi-spatial contamination ofCryptosporidiumin environmental aquatic matrices using low-cost, user-friendly, and sustainable strategies and submit implications on the presence ofCryptosporidiumin freshwater systems in a climate, health, and regulatory framework. Results Here, we present the microscopic detection ofCryptosporidiumoocysts in low-volume (50 mL) environmental samples of surface water (SW), sediments (BW), and substrate-associated biofilm (SAB) and in 1 L bulk SW investigated by PCR. The multi-spatial distribution ofCryptosporidiumoocysts in the low-volume (50 ml) aquatic matrices based on microscopy was highest at 69% (20/29) in SW and lowest at 50% (13/26) in BW. Immunofluorescence technique provided the highest microscopic positivity rate with 59% (17/29), 38% (10/26), and 50% (10/20) detection in SW, BW, and SAB, respectively. The detection and identification ofCryptosporidiumin 1 L bulk SW by PCR and sequence analysis was recorded in total at 21% (6/29) in sampling sites where the differential identification ofC. parvum, C. hominis,andCryptosporidiumspp. was 7% (2/29), 10% (3/29), and 3% (1/29), respectively. Conclusions We report the microscopical and first molecular epidemiologic data ofCryptosporidiumfrom the most significant environmental freshwater systems in the Philippines. The presence of the two main human and animal pathogenic speciesC. parvumandC. hominisfrom the largest lakes and major water reservoirs in the country calls for sustainable solutions in safeguarding the quality of freshwater resources in a climate, health, and regulatory approach

First report of Cryptosporidium hominis in a freshwater sponge

Identification of Cryptosporidium oocyst is essential in ensuring water quality fit for human use, consumption, and recreation. This communication proposes the supplemental analysis of substrate-associated biofilms, in particular, freshwater sponges in improving case finding of waterborne-protozoan pathogens (WBPP) in environmental aquatic samples. In this study, a small portion of a mature freshwater sponge under the Genus Spongilla was subjected to microscopic and molecular analysis to identify the presence of Cryptosporidium. Microscopic screening with modified Kinyoun's staining (MK) and microscopic confirmation using direct antibody fluorescent testing (IFT) returned with Cryptosporidium spp. positive findings. Molecular investigation resulted in the confirmation of Cryptosporidium hominis upon sequencing of PCR products and phylogenetic analysis. This is the first report of a pathogenic protozoan, C. hominis isolated from a freshwater sponge. The results of this study provide evidence of the value of expanding water quality assessment strategies to the analysis of substrate-associated biofilms and sponges in improving case finding of WBPP in natural aquatic environments. (C) 2019 Elsevier B.V. All rights reserved

Acanthamoebaspecies isolated from Philippine freshwater systems: epidemiological and molecular aspects

Free-living amoeba (FLA) research in the Philippines is still in its infancy but has, by far, demonstrated the presence of potentially pathogenic species.Acanthamoebamay cause sight-threatening and central nervous system infections to humans, yet its epidemiologic distribution from local environmental sources is yet to be defined. The present study aimed to provide a baseline epidemiologic distribution ofAcanthamoebaspp. in freshwater systems in the Philippines and establish potential pathogenicity of isolates through thermo-tolerance assay. A total of 63 water samples were collected from 13 freshwater systems all over the Philippine archipelago. The low-volume (50 ml) water samples were processed and cultured on non-nutrient agar lawned withEscherichia coliand observed for amoebic growth using light microscopy. Amoebic culture demonstrated 14.28% (9/63) positivity while further molecular testing of culture-positive plates usingAcanthamoeba-specific primers demonstrated 100% (9/9) confirmation ofAcanthamoebaspecies. Genotyping ofAcanthamoebaisolates revealed T1, T3, T4, T5, T7, T11, and T15 genotypes. Thermo-tolerance assay demonstrated that T5 and T7 genotypes were potentially pathogenic strains. The evidence of environmental distribution ofAcanthamoebaspp. in the freshwater systems in the Philippines and thermo-tolerance profile of isolates are significant aspects of amoeba study in public health and calls for initiatives in the dissemination of relevant information and the expansion of knowledge, awareness, and policies on pathogenic waterborne amoeba to mitigate, prevent, detect, and report cases of human infections

Well water sources simultaneous contamination with Cryptosporidium and Acanthamoeba in East-Southeast Asia and Acanthamoeba spp. in biofilms in the Philippines

Cryptosporidium is the leading agent of waterborne parasitic protozoan outbreaks and is the second leading cause of infant mortality due to diarrhoea worldwide. Acanthamoeba spp. causes Acanthamoeba keratitis (AK) and a life threatening condition known as granulomatous amoebic encephalitis (GAE). The present study aimed to assess the water quality of an indigenous and a rural community for waterborne parasitic protozoan contamination. Aquatic samples (n = 22) were processed by filtration of 500 mL portion through a 1.2 mu m pore size glass microfiber filter and eluted for light microscopy, culture in non-nutrient agar, and PCR analysis. Overall, 36% (8/22) of the investigated aquatic samples were positive for either Cryptosporidium spp. oocysts (13%; 3/22) or Acanthamoeba spp., (36%; 8/ 22) or both (13%; 3/22). Cryptosporidium spp. oocysts were detected in 27% (3/11) of wet season samples only while Acanthamoeba spp. were detected in 18% (2/11) and 55% (6/11) of wet and dry season samples, respectively. Subsequently, molecular detection for Acanthamoeba species identified A. lenticulata and A. hatchetti with 98-99% BLAST similarity. This is the first report on the simultaneous contamination of Cryptosporidium and Acanthamoeba in well water sources in East-Southeast Asia, the first detection of Acanthamoeba spp. in biofilms in the Philippines, and the longest viability demonstrated for A. lenticulata in two-year-old water samples stored at room temperature