Entamoeba histolytica Infections in a King Horseshoe Bat (Rhinolophus rex): A First Case Report

Bat-associated microbes: Opportunities and perils, an overview

The potential biotechnological uses of bat-associated bacteria are discussed briefly, indicating avenues for biotechnological applications of bat-associated microbes. The uniqueness of bats in terms of their lifestyle, genomes and molecular immunology may predispose bats to act as disease reservoirs. Molecular phylogenetic analysis has shown several instances of bats harbouring the ancestral lineages of bacterial (Bartonella), protozoal (Plasmodium, Trypanosoma cruzi) and viral (SARS-CoV2) pathogens infecting humans. Along with the transmission of viruses from bats, we also discuss the potential roles of bat-associated bacteria, fungi, and protozoan parasites in emerging diseases. Current evidence suggests that environmental changes and interactions between wildlife, livestock, and humans contribute to the spill-over of infectious agents from bats to other hosts. Domestic animals including livestock may act as intermediate amplifying hosts for bat-origin pathogens to transmit to humans. An increasing number of studies investigating bat pathogen diversity and infection dynamics have been published. However, whether or how these infectious agents are transmitted both within bat populations and to other hosts, including humans, often remains unknown. Metagenomic approaches are uncovering the dynamics and distribution of potential pathogens in bat microbiomes, which might improve the understanding of disease emergence and transmission. Here, we summarize the current knowledge on bat zoonoses of public health concern and flag the gaps in the knowledge to enable further research and allocation of resources for tackling future outbreaks.

Reusable Ag@TiO2-Based Photocatalytic Nanocomposite Membranes for Solar Degradation of Contaminants of Emerging Concern

Two significant limitations of using TiO2 nanoparticles for water treatment applications are reduced photocatalytic activity under visible radiation and difficulty recovering the particles after use. In this study, round-shaped Ag@TiO2 nanocomposites with a ≈21 nm diameter and a bandgap energy of 2.8 eV were synthesised by a deposition-precipitation method. These nanocomposites were immobilised into a porous poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) matrix and well-distributed within the pores. The photocatalytic activity of Ag@TiO2/PVDF-HFP against metronidazole (MNZ) under solar radiation was evaluated. Further, an adaptive neuro-fuzzy inference system (ANFIS) was applied to predict the effect of four independent variables, including initial pollutant concentration, pH, light irradiation intensity, and reaction time, on the photocatalytic performance of the composite membrane on MNZ degradation. The 10% Ag@TiO2/PVDF-HFP composite membrane showed a maximum removal efficiency of 100% after 5 h under solar radiation. After three use cycles, this efficiency remained practically constant, demonstrating the membranes' reusability and suitability for water remediation applications.

Prevalence of Gastrointestinal Parasites in the Frugivorous and the Insectivorous Bats in Southcentral Nepal

Bats are the only active flying placental mammals and are traditionally classified into mega- and microbats, which are, respectively, herbivorous and insectivorous in feeding habit. Though deforestation, habitat destruction, natural calamities, illegal hunting, and climate changes are the challenging threats for bats, the role of existing gastrointestinal (GI) parasites have not been evaluated yet in Nepal. Thus, the current study aims to determine the prevalence of GI parasites in bats from the Shaktikhor area at the Chitwan district of Southcentral Nepal. From July 2018 to February 2019, a total of 60 fecal samples of bats (30 from frugivorous bats and 30 from the insectivorous bats) were collected. These samples were preserved at 2.5% potassium dichromate solution. The fecal examination was carried out by the direct wet mount, concentrations, acid-fast staining, and sporulation techniques. Overall results showed the prevalence rate of 80% GI parasites. The parasites detected in the insectivorous bats were Ascarid spp., Capillarid sp., Cryptosporidium sp., Eimeria spp., Entamoeba sp., Giardia sp., Hymenolepis spp., Isospora sp., Oxyurid sp., Strongyle, and Strongyloides sp. In contrast, Eimeria sp., Entamoeba sp., and Hymenolepis sp. were detected in the frugivorous bats. Based on a wide diversity of parasite richness and parasitic concurrency measured by the prevalence rates, we suggest that GI parasitism might be a threatening factor in the insectivorous bats in the current study area.

Safe and efficient degradation of metronidazole using highly dispersed β-FeOOH on palygorskite as heterogeneous Fenton-like activator of hydrogen peroxide

In this study, the highly dispersed β-FeOOH on palygorskite (H-β-FeOOH/PAL) was prepared and investigated as Fenton catalyst for H₂O₂ activation towards metronidazole (MTZ). Based on electron spin resonance and probe techniques, hydroxyl radicles (^•OH) as main reactive oxygen species was confirmed, and much more ^•OH were generated over H-β-FeOOH/PAL than T-β-FeOOH/PAL using traditional impregnation method. The enhanced Fe(III) to Fe(II) cycle due to the highly dispersed β-FeOOH leads to the fast degradation of metronidazole over H-β-FeOOH/PAL. 92.8% of MTZ degradation efficiency was achieved within 180 min by adding 17 mmol/L H₂O₂ and 40 mg/L of H-β-FeOOH/PAL at pH 6.0. The bacterial cytotoxicity during MTZ degradation process also decreased with reaction time and achieved zero at 66 min, indicating MTZ was not only efficiently degraded but also safely transformed. Besides, the possible MTZ degradation pathway was further proposed based on the intermediates identified by HPLC-MS.

Survey on helminths and protozoa of free-living Neotropical bats from Northeastern Brazil

Bats are considered important reservoirs of pathogens of veterinary and medical relevance worldwide. However, despite the increasing attention paid towards the central role of bats in the spreading of some zoonotic infections, studies on their own parasites remain patchy especially in Neotropical regions. Understanding the relationships occurring between bats and their pathogens is a crucial step to determine the implications undermining the ecology and biology of these animals. The present study aims to assess the endoparasitic fauna of Neotropical bats from Northeastern Brazil, with a particular focus on helminths and protozoa. From October 2016 to March 2017, 54 fresh faecal samples were collected in stable shelters inhabited by three different bat species (i.e., Molossus molossus, Myotis lavali and Noctilio albiventris). Samples were analysed using four different techniques (i.e., Centrifugal Sedimentation, Flotation Technique, Spontaneous Sedimentation Technique and FLOTAC^®). A total of 96.29% (52/54) samples were positive for at least one gastrointestinal parasite and 11 different families were identified. In particular, 63.6% (7/11) of the families were of helminths and 36.4% (4/11) of protozoa. Helminths were classified into two different classes (Nematoda and Cestoda) and seven families, whereas the four protozoa classes detected (i.e., Coccidia, Gregarinomorphe, Lobosea and Zoomastigophora) into four families. Eggs of Ancylostomatidae and Hymenolepididae were the most abundan. The findings of this present study demonstrate that Neotropical bats from Northeastern Brazil are parasitized by a wide number of parasites, and some of them may have important implications for Public Health.

Evaluation of the intestinal microbial diversity in miniature pig after orally infected with Entamoeba histolytica

The objective of this study was to analyze the difference in intestinal microbial diversity between healthy and (Entamoeba histolytica) orally infected minipig. Enterobacterial repetitive intergenic consensus (ERIC)-PCR was applied to analyze this diversity and dynamic change, including the duodenum, jejunum, ileum, cecum, and rectum from healthy and orally infected minipig at different time points. The results showed that the intestinal microbial community of the control minipigs was stable and the ERIC-PCR band numbers of the control minipigs were the lowest in the rectum and highest in the cecum. ERIC-PCR bands of orally inoculated minipigs showed no obvious change until 24 h after postinoculation (hpi). The numbers of the ERIC-PCR bands gradually decreased from 24 to 72 hpi, then, with the development of disease, the band numbers gradually increased until 6 days postinoculation. The prominent bacteria had changed in the presence of E. histolytica infection and the DNAstar of staple of ERIC-PCR showed that obligate aerobes and facultative aerobes (Escherichia coli, Shigella, Salmonella) became the preponderant bacilli in the intestine of orally infected minipigs with E. histolytica. This study has provided significant data to clarify the intestinal microbial diversity and dynamic change of healthy and E. histolytica orally infected minipigs.

Intestinal microbial community diversity between healthy and orally infected rabbit with Entamoeba histolytica by ERIC-PCR

Enterobacterial repetitive intergenic consensus (ERIC)-PCR was applied to analyze the difference of intestinal microbial community diversity between healthy and orally infected rabbits with Entamoeba histolytica. The dynamic changes in different parts of digestive system including the duodenum, jejunum, ileum, caecum, and rectum in healthy and infected rabbits at different time points were also tested. The intestinal microbial community of the control healthy rabbits was steady, and the total number of ERIC-PCR bands in the control healthy rabbit was the least in the rectum and the most in the caecum. ERIC-PCR bands of orally inoculated rabbits did not obviously change until 24 h after postinoculation (p.i.). The numbers of the ERIC-PCR bands gradually decreased from 24 to 72 h p.i., and then, with the development of disease, the band numbers gradually increased until 6 days p.i. Sequence analysis showed that the nucleotide sequence homologies of the fragment about 1,200 bp of infected ileum sampled at 32 h p.i. were above 95 % with Sinorhizobium meliloti enterobacterial, Erwinia amylovora and Salmonella typhimurium, and the nucleotide sequence homologies of the fragment about 300 bp of infected ileum sampled at 48 h p.i. were more than 90 % with Xanthomonas campestris enterobacterial, Yersinia enterocolitica subsp., Shigella flexneri, S. meliloti enterobacterial, Yersinia pestis, Klebsiella pneumoniae subsp., and Escherichia coli. The prominent bacteria had changed after E. histolytica infection. The DNAstar of staple of ERIC-PCR showed that aerobe and facultative aerobe (E. coli, Shigella, and Salmonella) became preponderant bacilli in the intestine of orally infected rabbits with E. histolytica.

WITHDRAWN: Use of a recombinant Entamoeba histolytica cysteine proteinase antigen to evaluation of the efficacy of immune protective responses in miniature pigs

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Evaluation of the efficacy of a recombinant Entamoeba histolytica cysteine proteinase gene (EhCP5) antigen in Minipig

Entamoeba histolytica cysteine proteinase gene 5(EhCP5) is one of the major proteinase genes of all EhCP-transcripts. The amebiasis cysteine proteinase gene encoding an antigen from E. histolytica, as well as the recombinant EhCP5, obtained by cloning and expression of the EhCP5 gene in heterologous host Escherichia coli BL-21 (DE3), were used to evaluate their ability to induce immune protective responses in Minipig against challenge infection in a minipig-E. histolytica model. There was a 52.27% reduction (P<0.001) in the group of recovery of challenged E. histolytica compared with that in the control group. Specific anti-EhCP5 antibodies from immune protected minipig had significantly higher levels of immunoglobulin G (IgG) (P<0.0001). Our data will help to know the mechanism of vaccinal protection of E. histolytica.