Leptospirosis in horses: Sentinels for a neglected zoonosis? A systematic review

Background and Aim

Leptospirosis is considered a neglected tropical zoonosis in low-income countries due to surveillance system limitations and non-specificity of symptoms. Humans become infected through direct contact with carrier animals or indirectly through Leptospira-contaminated environments. Conventionally, equines have been considered an uncommon source of leptospirosis, but recent publications in Latin America suggest that their role in the maintenance and dispersion of the bacteria could be more relevant than expected, as horses are susceptible to a wide variety of zoonotic Leptospira spp. from domestic and wild animals with which they share the environment. A systematic review of the published literature was conducted to compile the available information on Leptospira spp. in Ecuador, with a special focus on equine leptospirosis, to better understand the epidemiology of the bacterium and identify possible knowledge gaps.

Materials and Methods

A systematic review of the published literature was conducted in PubMed, SciELO and Web of Science databases to compile the available information on Leptospira spp. in Ecuador, with a special focus on equine leptospirosis, to better understand the epidemiology of the bacterium. We used a combination of the terms (Leptospira OR Leptospirosis) AND Ecuador, without restrictions on language or publication date.

Results

Our literature review reveals that published scientific information is very scarce. Eighteen full-text original scientific articles related to Leptospira or leptospirosis cases in Ecuador were included in the systematic review. Most of the studies reported data obtained from one of the four regions (Coast), and specifically from only one of the 24 Provinces of Ecuador (Manabí), which evidence a large information bias at the geographical level. Furthermore, only the studies focused on humans included clinical signs of leptospirosis and there is only one study that analyzes the presence of Leptospira spp. in water or soil as a risk factor for pathogen transmission. Finally, only one study investigated Leptospira in horses.

Conclusion

Since sentinel species can provide useful data on infectious diseases when epidemiologic al information is lacking, and horses could be considered excellent sentinel species to reveal circulating serovars, we propose developing a nationwide surveillance system using horses. This cost-effective epidemiological survey method provides a baseline for implementing specific prevention and control programs in Ecuador and neighboring developing countries.

Domestic dogs in indigenous Amazonian communities: key players in Leptospira cycling and transmission?

Background

Leptospirosis is the world's most common zoonotic disease. Mitigation and control rely on pathogen identification and understanding the roles of potential reservoirs in cycling and transmission. Underreporting and misdiagnosis obscure the magnitude of the problem and confound efforts to understand key epidemiological components. Difficulties in culturing hamper the use of serological diagnostics and delay the development of DNA detection methods. As a result, especially in complex ecosystems, we know very little about the importance of different mammalian host species in cycling and transmission to humans.

Methodology/Principal Findings

We sampled five indigenous Kichwa communities living in the Yasuní National Park in the Ecuadorian Amazon basin. Blood and urine samples from domestic dogs were collected to assess the exposure of these animals to Leptospira, and to identify the circulating species. Microscopic Agglutination Tests with a panel of 22 different serovars showed anti-leptospira antibodies in 36 sampled dogs (75%), and 10 serotypes were detected. Two DNA-based detection assays revealed pathogenic Leptospira DNA in 18 of 19 dog urine samples (94.7%). Amplicon sequencing and phylogenetic analysis of 16s rDNA and SecY genes from 15 urine samples revealed genetic diversity within two of three different Leptospira species: noguchii (n=7), santarosai (n=7), and interrogans (n=1).

Conclusions/Significance

The high prevalence of antibodies and Leptospira DNA provides strong evidence for high rates of past and current infections. Such high prevalence has not been previously reported for dogs. These dogs live in the peridomestic environment in close contact with humans, yet they are free-ranging animals that interact with wildlife. This complex web of interactions may explain the diverse types of pathogenic Leptospira observed in this study. Our results suggest that domestic dogs are likely to play an important role in the cycling and transmission of Leptospira. Future studies in areas with complex ecoepidemiology will enable better parsing of the significance of genotypic, environmental, and host characteristics.

Occurrence of SARS-CoV-2 reinfections at regular intervals in Ecuador

SARS-CoV-2 reinfection is defined as a new infection with a different virus variant in an individual who has already recovered from a previous episode of COVID-19. The first case of reinfection in the world was described in August 2020, since then, reinfections have increased over time and their incidence has fluctuated with specific SARS-CoV-2 variant waves. Initially, reinfections were estimated to represent less than 1% of total COVID-19 infections. With the advent of the Omicron variant, reinfections became more frequent, representing up to 10% of cases (based on data from developed countries). The frequency of reinfections in Latin America has been scarcely reported. The current study shows that in Ecuador, the frequency of reinfections has increased 10-fold following the introduction of Omicron, after 22 months of surveillance in a single center of COVID-19 diagnostics. Suspected reinfections were identified retrospectively from a database of RT-qPCR-positive patients. Cases were confirmed by sequencing viral genomes from the first and second infections using the ONT MinION platform. Monthly surveillance showed that the main incidence peaks of reinfections were reached within four to five months, coinciding with the increase of COVID-19 cases in the country, suggesting that the emergence of reinfections is related to higher exposure to the virus during outbreaks. This study performed the longest monitoring of SARS-CoV-2 reinfections, showing an occurrence at regular intervals of 4-5 months and confirming a greater propensity of Omicron to cause reinfections.

First case of within-host co-infection of different SARS-CoV-2 variants in Ecuador

Background

COVID-19 infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause mild symptoms to severe illness and death. Co-infections of SARS-CoV-2 with other respiratory viruses have been described. However, two SARS-CoV-2 lineage co-infection have been rarely reported.

Methodology

A genotyping analysis and two different types of whole genome sequencing were performed (Illumina MiniSeq and ONT MinION). When examining the phylogenetic analysis in NextClade and Pangolin webservers, and considering the genotyping findings, conflicting results were obtained.

Results

The raw data of the sequencing was analyzed, and nucleotide variants were identified between different reads of the virus genome. B.1 and P.1 lineages were identified within the same sample.

Conclusions

We concluded that this is a co-infection case with two SARS-CoV-2 lineages, the first one reported in Ecuador.

SARS-CoV-2 detection and sequencing in heart tissue associated with myocarditis and persistent arrhythmia: A case report

BACKGROUND

SARS-CoV-2 uses the human cell receptor angiotensin-converting enzyme (ACE2). ACE2 is widely present in the cardiovascular system including the myocardium and the conduction system. COVID-19 patients that present severe symptoms have been reported to have complications involving myocardial injuries caused by the virus. Here we report the detection of SARS-CoV-2 by whole genome sequencing in the endocardium of a patient with severe bradycardia.

CASE PRESENTATION

We report a case of a 34-year-old male patient with COVID-19 tested by PCR, he started with gastrointestinal symptoms, however, he quickly deteriorated his hemodynamic state by means of myocarditis and bradycardia. After performing an endocardium biopsy, it was possible to identify the presence of SARS-CoV-2 in the heart tissue and to sequence its whole genome using the ARTIC-Network protocol and a modified tissue RNA extraction method. The patient's outcome was improved after a permanent pacemaker was implanted.

CONCLUSIONS

It was possible to identify a SARS-CoV-2 clade 20A in the endocardium of the reported patient.

Genomic epidemiology of SARS-CoV-2 transmission lineages in Ecuador

Characterisation of SARS-CoV-2 genetic diversity through space and time can reveal trends in virus importation and domestic circulation, and permit the exploration of questions regarding the early transmission dynamics. Here we present a detailed description of SARS-CoV-2 genomic epidemiology in Ecuador, one of the hardest hit countries during the early stages of the COVID-19 pandemic. We generate and analyse 160 whole genome sequences sampled from all provinces of Ecuador in 2020. Molecular clock and phylgeographic analysis of these sequences in the context of global SARS-CoV-2 diversity enable us to identify and characterise individual transmission lineages within Ecuador, explore their spatiotemporal distributions, and consider their introduction and domestic circulation. Our results reveal a pattern of multiple international importations across the country, with apparent differences between key provinces. Transmission lineages were mostly introduced before the implementation of non-pharmaceutical interventions (NPIs), with differential degrees of persistence and national dissemination.

SARS-CoV-2 genome sequencing from COVID-19 in Ecuadorian patients: a whole country analysis

SARS-CoV-2, the etiological agent of COVID-19, was first described in Wuhan, China in December 2019 and has now spread globally. Ecuador was the second country in South America to confirm cases and Guayaquil was one of the first cities in the world to experience high mortality due to COVID-19. The aim of this study was to describe the lineages circulating throughout the country and to compare the mutations in local variants, to the reference strain. In this work we used the MinION platform (Oxford Nanopore Technologies) to sequence the whole SARS-CoV-2 genomes of 119 patients from all provinces of Ecuador, using the ARTIC network protocols. Our data from lineage assignment of the one hundred and nineteen whole genomes revealed twenty different lineages. All genomes presented differences in the S gene compared to the Wuhan reference strain, being the D614G amino acid replacement the most common change. The B.1.1.119 lineage was the most frequent and was found in several locations in the Coast and Andean region. Three sequences were assigned to the new B.1.1.7 lineage. Our work is an important contribution to the understanding of the epidemiology of SARS-CoV-2 in Ecuador and South America.

Genomic epidemiology of SARS-CoV-2 transmission lineages in Ecuador

Characterisation of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) genetic diversity through space and time can reveal trends in virus importation and domestic circulation and permit the exploration of questions regarding the early transmission dynamics. Here, we present a detailed description of SARS-CoV-2 genomic epidemiology in Ecuador, one of the hardest hit countries during the early stages of the coronavirus-19 pandemic. We generated and analysed 160 whole genome sequences sampled from all provinces of Ecuador in 2020. Molecular clock and phylogeographic analysis of these sequences in the context of global SARS-CoV-2 diversity enable us to identify and characterise individual transmission lineages within Ecuador, explore their spatiotemporal distributions, and consider their introduction and domestic circulation. Our results reveal a pattern of multiple international importations across the country, with apparent differences between key provinces. Transmission lineages were mostly introduced before the implementation of non-pharmaceutical interventions, with differential degrees of persistence and national dissemination.

Vaginal Microbiota Evaluation and Lactobacilli Quantification by qPCR in Pregnant and Non-pregnant Women: A Pilot Study

Pregnancy outcomes and women's health are directly affected by vaginal microbiota. This microbiota consists of a dynamic ecosystem of various microbes in different ratios, which in healthy conditions protect the vaginal epithelium from infections. However, cases of vaginal infection are regularly diagnosed in women of reproductive age, contributing to more severe outcomes. Therefore, our main goal was to determine the prevalence of bacterial vaginosis (BV), aerobic vaginitis (AV), and vulvovaginal candidiasis (VVC) among Ecuadorian pregnant and non-pregnant women. A cross-sectional study was conducted among 217 women between 13 and 40 years old seeking primary healthcare in Carlos Andrade Marin Hospital (HCAM), Gynecological-Obstetric Hospital Isidro Ayora (HGOIA) and Center for Teaching Health Cipriana Dueñas during October 2018 to February 2019. The classical characterization of the vaginal microbiota was performed through microscopy by the Nugent criteria to evaluate the presence of BV, healthy and intermediate microbiota, by the criteria of Donders to determine the presence of AV and by the Marot-Leblond criteria to diagnose VVC. DNA extraction from vaginal samples and Polymerase Chain Reaction (PCR) analysis was performed to characterize the presence of Gardnerella spp., Mobiluncus mulieris, Escherichia coli, Enterococcus spp., and Lactobacillus spp. Finally, quantification of the lactobacilli was performed by quantitative real-time PCR (qPCR) for samples from women with normal vaginal microbiota and women with AV. Our results showed 52% of women with healthy microbiota, 7% with intermediate microbiota, and 41% with vaginal dysbiosis, comprising 27% with AV, 8% with BV and 4% with VVC and 2% with co-infections or co-dysbiosis. Additionally, a higher amount of lactobacilli were found in pregnant women when compared to non-pregnant women, while AV cases were characterized by a significant drop of Lactobacillus spp., more precisely, between 1E3 and 1E5 colony forming units (CFU)/ml. Finally, women with normal vaginal microbiota showed an average load of lactobacilli between 1E6 and 1E7 CFU/ml. This pilot study showed no statistically significant differences between pregnant and non-pregnant women, pointing to the possibility to use lactobacilli quantification for the prevention of future vaginal infections.

Genome sequencing of the first SARS-CoV-2 reported from patients with COVID-19 in Ecuador

SARS-CoV-2, the etiological agent of COVID-19 was first described in Wuhan in December 2019 and has now spread globally. Ecuador was the second country in South America to report confirmed cases. The first case reported in Quito, the capital city of Ecuador, was a tourist who came from the Netherlands and presented symptoms on March 10th, 2020 (index case). In this work we used the MinION platform (Oxford Nanopore Technologies) to sequence the metagenome of the bronchoalveolar lavage (BAL) from this case reported, and subsequently we sequenced the whole genome of the index case and other three patients using the ARTIC network protocols. Our data from the metagenomic approach confirmed the presence of SARS-CoV-2 coexisting with pathogenic bacteria suggesting coinfection. Relevant bacteria found in the BAL metagenome were Streptococcus pneumoniae, Mycobacterium tuberculosis, Staphylococcus aureus and Chlamydia spp. Lineage assignment of the four whole genomes revealed three different origins. The variant HEE-01 was imported from the Netherlands and was assigned to B lineage, HGSQ-USFQ-018, belongs to the B.1 lineage showing nine nucleotide differences with the reference strain and grouped with sequences from the United Kingdom, and HGSQ-USFQ-007 and HGSQ-USFQ-010 belong to the B lineage and grouped with sequences from Scotland. All genomes show mutations in their genomes compared to the reference strain, which could be important to understand the virulence, severity and transmissibility of the virus. Our findings also suggest that there were at least three independent introductions of SARS-CoV-2 to Ecuador.

Novel small RNA expression libraries uncover hsa-miR-30b and hsa-miR-30c as important factors in anoikis resistance

MicroRNAs (miRNAs) have been widely studied in order to elucidate their biological functions. MicroRNA microarrays or miRNA overexpression libraries generated by synthesis and cloning of individual miRNAs have been used to study their different roles. In this work, we have developed a novel methodology to express mature miRNAs and other small RNAs from a double convergent RNA polymerase III promoter. We show that the generated miRNAs function similarly to those processed from primary transcripts or pri-miRNAs. This system allowed us to produce a lentiviral library expressing the whole population of small RNAs present in a metastatic cell line. A functional screening using this library led to the identification of hsa-miR-30b and hsa-miR-30c as negative regulators of cell death induced by loss of attachment (anoikis). Importantly, we demonstrated that the acquisition of anoikis resistance via these miRNAs is achieved through down-regulation of caspase 3 expression. Moreover, overexpression of these miRNAs resulted in a decrease of other types of caspase 3-dependent cell death and enhanced the survival of MCF10A acinar cells in morphogenesis assays, suggesting a putative role as oncomirs. In summary, this novel methodology provides a powerful and effective way for identifying novel small RNAs involved in a particular biological process.

Ion exchangers NHX1 and NHX2 mediate active potassium uptake into vacuoles to regulate cell turgor and stomatal function in Arabidopsis

Intracellular NHX proteins are Na(+),K(+)/H(+) antiporters involved in K(+) homeostasis, endosomal pH regulation, and salt tolerance. Proteins NHX1 and NHX2 are the two major tonoplast-localized NHX isoforms. Here, we show that NHX1 and NHX2 have similar expression patterns and identical biochemical activity, and together they account for a significant amount of the Na(+),K(+)/H(+) antiport activity in tonoplast vesicles. Reverse genetics showed functional redundancy of NHX1 and NHX2 genes. Growth of the double mutant nhx1 nhx2 was severely impaired, and plants were extremely sensitive to external K(+). By contrast, nhx1 nhx2 mutants showed similar sensitivity to salinity stress and even greater rates of Na(+) sequestration than the wild type. Double mutants had reduced ability to create the vacuolar K(+) pool, which in turn provoked greater K(+) retention in the cytosol, impaired osmoregulation, and compromised turgor generation for cell expansion. Genes NHX1 and NHX2 were highly expressed in guard cells, and stomatal function was defective in mutant plants, further compromising their ability to regulate water relations. Together, these results show that tonoplast-localized NHX proteins are essential for active K(+) uptake at the tonoplast, for turgor regulation, and for stomatal function.

The AtNHX1 exchanger mediates potassium compartmentation in vacuoles of transgenic tomato

NHX-type antiporters in the tonoplast have been reported to increase the salt tolerance of various plants species, and are thought to mediate the compartmentation of Na(+) in vacuoles. However, all isoforms characterized so far catalyze both Na(+)/H(+) and K(+)/H(+) exchange. Here, we show that AtNHX1 has a critical involvement in the subcellular partitioning of K(+), which in turn affects plant K(+) nutrition and Na(+) tolerance. Transgenic tomato plants overexpressing AtNHX1 had larger K(+) vacuolar pools in all growth conditions tested, but no consistent enhancement of Na(+) accumulation was observed under salt stress. Plants overexpressing AtNHX1 have a greater capacity to retain intracellular K(+) and to withstand salt-shock. Under K(+)-limiting conditions, greater K(+) compartmentation in the vacuole occurred at the expense of the cytosolic K(+) pool, which was lower in transgenic plants. This caused the early activation of the high-affinity K(+) uptake system, enhanced K(+) uptake by roots, and increased the K(+) content in plant tissues and the xylem sap of transformed plants. Our results strongly suggest that NHX proteins are likely candidates for the H(+)-linked K(+) transport that is thought to facilitate active K(+) uptake at the tonoplast, and the partitioning of K(+) between vacuole and cytosol.

[Changes in the small intestine mucosa in chronic alcoholism]

Morphologic and enzyme induction phenomena changes in the small bowel mucosa produced by excessive alcohol intake were studied. Both aspects may have nutritional repercussions in alcoholic patients. Three groups of patients were included in the study: group I made up of 20 healthy controls, group II with 30 alcoholic patients with active alcohol intake at the time of the study and group III made up of 30 alcoholics following abstinence. The nutritional status, possible existence of associated liver disease, intestinal morphology and the mucosal and serum gamma glutamyltranspeptidase (GGT) levels were evaluated. The morphologic changes observed under the study conditions, with normal levels of ingestion in alcoholic with active alcohol intake, were mild and could be related with the nutritional status and folate deficiency which some presented than being secondary to a direct toxic effect of the alcohol. Moreover, significant increases were observed in the GGT in the intestinal mucosa of alcoholics with active intake (3.97 +/- 1.37 mU/g of tissue) with respect to the control group (1.86 +/- 0.7 mU/g). The changes were rapidly reversible following abstinence and correlated with the changes observed in serum, thus suggesting an enzymatic induction mechanism.

Chronic diarrhea with normal stool and colonic examinations: organic or functional?

To investigate whether the clinical history and basic laboratory test results can differentiate between an organic or functional cause of chronic diarrhea and thus avoid unnecessary hospital admissions and invasive procedures, we reviewed the charts of 58 adult patients admitted during 6 years because of chronic diarrhea who had normal stool and colonic examinations. The final diagnoses were irritable bowel syndrome in 34 patients, organic diarrhea in 21, and unknown cause in three. The following clinical data did not help in the differential diagnosis: age, sex, duration of diarrhea, presence of continuous diarrhea, abdominal pain, stool frequency or volume, and presence of stool mucus. Significant weight loss, nocturnal diarrhea, and the absence of tenesmus were associated with an organic cause. One or more laboratory alterations (increased erythrocyte sedimentation rate, anemia, hypokalemia, and low serum albumin level) were found in 62% of patients with organic diarrhea but in only 3% of those with functional disease; p less than 0.001. In 20 of 21 patients with organic diarrhea, an syndromic diagnosis (fat malabsorption, n = 13; inflammatory bowel disease, n = 4; and secretory diarrhea, n = 3) could be obtained with three simple tests (stool fat, rectal biopsy, and fecal water osmolality and electrolyte determination, respectively). Our study confirms that a detailed history and a few simple laboratory data can help to distinguish between functional and organic diarrhea and so avoid extensive investigation. The syndromic diagnosis of organic diarrhea can also be approximated with relatively easy tests.

[Superficial gastric cancer in Barcelona. Importance of the detection of severe epithelial dysplasia in biopsies obtained under endoscopic control in the diagnosis of early gastric cancer]

BACKGROUND

Severe mucosal dysplasia (SMD) in endoscopic gastric biopsies is a controversial lesion because some authors consider it as an histologic lesion associated to superficial gastric cancer (SCG). This study is aimed to asses the prevalence of SCG in Barcelona; if the presence of SMD is associated to SCG and, the clinical and endoscopic manifestations which induced the diagnosis.

METHODS

We studied a total of 4,800 patients who had been submitted to gastroscopy during 1.5 years. A total of 79 patients suffered gastric cancer, 56 of them were submitted to resection. Ten of these 56 patients (17%) had SCG. The most frequent first clinical manifestation of SCG was gastrointestinal haemorrhage.

RESULTS

Endoscopic aspect suggested malignancy in five cases. Biopsies during endoscopy allow diagnosis of gastric cancer in five. In four histologic studies showed SMD. In the tenth patient, the first endoscopy with biopsies showed a gastric peptic ulcer. A later endoscopic control showed the persistence of the macroscopically benign lesion but one among seven biopsies showed adenocarcinoma. The four patients with SMD had gastric cancer in further endoscopic procedures, except in one which was operated after two endoscopies demonstrating SMD.

CONCLUSIONS

This study suggests: 1) prevalence of SGC in Barcelona is similar than the other European countries. 2) haemorrhage is a frequent first manifestation of SCG, and 3) the finding of SMD in endoscopic biopsy strongly suggests the presence of SCG in the stomach.