Clostridium perfringens in central Colombia: frequency, toxin genes, and risk factors.

Clostridium perfringens is an opportunistic bacterium that causes intestinal diseases in both humans and animals. This study aimed to assess the frequency of C. perfringens and the presence of toxin-encoding genes in fecal samples from individuals with or without gastrointestinal symptoms in the Department of Boyacá, Colombia. Additionally, risk factors associated with carriage and disease development were analyzed. A total of 114 stool samples were analyzed using a molecular test based on specific polymerase chain reaction (PCR) targeting 16S-rRNA and alpha toxin (cpa) genes. For individuals with a positive result for the PCR test, stool samples were cultured on Tryptose Sulfite Cycloserine (TSC) agar. Two to five colonies forming units were selected based on phenotypic characteristics, resulting in 56 bacterial isolates. These isolates were then analyzed for toxin-coding genes associated with gastrointestinal diseases. In addition, sociodemographic and clinical data from 77 individuals were also analyzed. The overall frequency of C. perfringens was 19.3% (n = 22/114). The detection frequency in 77 individuals with clinical data was 16.6% (n = 5/30) among symptomatic individuals and 21.2% (n = 10/47) among asymptomatic individuals. All 56 isolates obtained carried the cpa gene, while cpb2 was present in 10.7% (n = 6/56); cpe and cpb genes were not detected. Notably, diabetes and autoimmune diseases are significantly associated with an increased risk of C. perfringens detection (adjusted OR 8.41: 95% CI 1.32-35.89). This study highlights an elevated frequency of C. perfringens and the presence of the cpb2 gene in asymptomatic individuals compared with their symptomatic counterparts. These findings offer insights into the distribution and virulence factors of C. perfringens at a micro-geographical level. This information supports the need for developing tailored prevention strategies based on local characteristics to promote active surveillance programs based on molecular epidemiology.

Asymptomatic Malaria Reservoirs in Honduras: A Challenge for Elimination.

BACKGROUND: Efforts on a global scale for combating malaria have achieved substantial progress over the past twenty years. Two Central American nations have accomplished their goal of eliminating malaria: El Salvador and Belize. Honduras has decreased the incidence of malaria and now reports fewer than 4000 malaria cases annually, aspiring to reach elimination by 2030. To accomplish this goal, it is essential to assess the existing strategies employed for malaria control and to address the task of incorporating novel intervention strategies to identify asymptomatic reservoirs. METHODS: A survey for detecting asymptomatic cases was carried out in the community of Kaukira, in Gracias a Dios, Honduras, focusing on malaria transmission during 2023. Asymptomatic community members were recruited as participants, malaria screening was performed through a rapid diagnostic test in situ, and a blood sample was collected on filter paper. Highly sensitive molecular assays based on photo-induced electron transfer PCR (PET-PCR) were performed to detect the two species of Plasmodium circulating in Honduras: Plasmodium vivax and Plasmodium falciparum. In addition, the identification of the parasite species was verified by amplifying three genetic markers (Pvmsp3α, Pvmsp3ß, and Pfmsp1). RESULTS: A total of 138 participants were recruited, mostly adult women. All individuals tested negative on the rapid diagnostic test. Positive results for malaria were detected by PET-PCR in 17 samples (12.3%). Most samples (12 out of 17) were amplified with a Ct value between 37 and 42, indicating very low parasitemias. Out of the 17 samples, 16 of them also showed amplification in the species assays. There were nine cases of P. falciparum infections and seven cases of P. vivax infections that were further confirmed by nested PCR (nPCR) of Pvmsp3 and Pfmsp1. Parasitemias ranged from 100 p/µL to less than 0.25 p/µL. One sample showed mixed infection. CONCLUSIONS: The existence of asymptomatic malaria reservoirs in Honduras can contribute to disease transmission and pose a challenge that may hinder elimination efforts, requiring public health authorities to modify surveillance strategies to identify the disease and treat this population accordingly.

Unravelling heterogeneous malaria transmission dynamics in the Peruvian Amazon: insights from a cross-sectional survey.

BACKGROUND: Malaria remains a global health challenge, particularly in Peru's Loreto region. Despite ongoing efforts, high infection rates and asymptomatic cases perpetuate transmission. The Peruvian Ministry of Health's "Zero Malaria Plan" targets elimination. This novel study combines microscopic, molecular, and serological techniques to assess transmission intensity, identify epidemiological risk factors, and characterize species-specific patterns across villages. The findings aim to inform targeted interventions and support broader malaria elimination efforts in line with the Zero Malaria Plan initiative. METHODS: A cross-sectional malaria survey was conducted in the Zungarococha community, comprising the villages Llanchama (LL), Ninarumi (NI), Puerto Almendra (PA), and Zungarococha (ZG), using microscopic, molecular, and serological techniques to evaluate malaria transmission intensity. Statistical analysis, including multivariate-adjusted analysis, seroprevalence curves, and spatial clustering analysis, were performed to assess malaria prevalence, exposure, and risk factors. RESULTS: The survey revealed a high prevalence of asymptomatic infections (6% by microscopy and 18% by PCR), indicating that molecular methods are more sensitive for detecting asymptomatic infections. Seroprevalence varied significantly between villages, reflecting the heterogeneous malaria transmission dynamics. Multivariate analysis identified age, village, and limited bed net use as significant risk factors for malaria infection and species-specific exposure. Seroprevalence curves demonstrated community-specific patterns, with Llanchama and Puerto Almendra showing the highest seroconversion rates for both Plasmodium species. CONCLUSIONS: The study highlights the diverse nature of malaria transmission in the Loreto region, particularly nothing the pronounced heterogeneity as transmission rates decline, especially in residual malaria scenarios. The use of molecular and serological techniques enhances the detection of current infections and past exposure, aiding in the identification of epidemiological risk factors. These findings underscore the importance of using molecular and serological tools to characterize malaria transmission patterns in low-endemic areas, which is crucial for planning and implementing targeted interventions and elimination strategies. This is particularly relevant for initiatives like the Zero Malaria Plan in the Peruvian Amazon.

SARS-CoV-2 Research in Dogs (Canis lupus familiaris) and Felines (Felis silvestris catus) Domiciled in an International Border Region (Paraguay and Brazil).

Introduction: COVID-19 is an infectious disease caused by SARS-CoV-2 that has become a serious threat to public health owing to its rapid spread from aerosols from infected people. Despite being considered a strictly human disease, there are reports in the literature about animals with confirmed presence of the virus. Aim: Owing to the scarcity of scientific literature on the potential for infection of animals and their importance for One Health, the objective of this work was to research SARS-CoV-2 RNA in felines (Felis silvestris catus) and dogs (Canis lupus familiaris) domiciled. Materials and Methods: Oropharyngeal swabs were collected from domestic dogs and cats belonging to patients diagnosed with COVID-19 from August to October 2021 and residents of the northwest and west regions of Paraná, Brazil. Results: Of the 34 samples collected, 14 were from dogs and 20 from cats. Three of these samples tested positive in real-time PCR, and two of them were also positive in the immunochromatographic test. After testing positive in real-time PCR, the samples underwent genetic sequencing using the Illumina COVIDSeq test. Of the 34 samples collected, three (9%), all of them female and from the feline species, tested positive in real-time PCR, with two of these (67%) also testing positive in the immunochromatographic test. Regarding sequencing, it was possible to sequence the three samples aligned with the AY.101 lineage, corresponding to the Delta variant. Conclusion: The occurrence of SARS-CoV-2 infection in dogs and cats is seen as an unintended event with significant implications for public health, including its potential transmission to other animal species. Further research is required to enhance our understanding of how this disease spreads among these animals and its broader impact on One Health initiatives.

Histological and Ultrastructural Changes in Lungs One Year Post Asymptomatic or Mild SARS-CoV-2 Infection: Evaluating the Potential for Active Virus Presence / Cambios Histológicos y Ultraestructurales en los Pulmones un Año Después de una Infección Asintomática o Leve por SARS-CoV-2: Evaluación del Potencial de Presencia Activa del Virus

SUMMARY: Prior research on post-COVID-19 or long COVID primarily focused on the presence of SARS-CoV-2 mostly in symptomatic patients. This study aimed to investigate the persistence of SARS-CoV-2 after 1 year of asymptomatic or mild COVID-19. SARS-CoV-2 infected and control K18-hACE2 transgenic mice (n=25) were studied. Moderate and severe symptomatic subjects were sacrificed after eight days, while mild or asymptomatic mice were kept in BSL-III for twelve months. Analyses included general condition, histochemistry, immunohistochemistry, transmission electron microscopy, and qRT-PCR. Lungs from the twelve-month group showed thickening of alveolar walls, with some lungs exhibiting the recruitment of inflammatory cells, the presence of SARS- CoV-2 mRNA, immunopositivity for the SARS-CoV-2 spike protein, and TEM showed viruses (60-125 nm) within vesicles, indicating continued replication. Certain lung samples showed persistent SARS-CoV-2 presence in Club cells, endothelial cells, and macrophages. The eight-day group exhibited viral interstitial pneumonitis, SARS-CoV-2 immunopositivity, and mRNA. The eight-day hearts displayed viral mRNA, while the twelve-month hearts tested negative. Some asymptomatic twelve-month subjects presented reduced surfactant, basal membrane thickening, fibrosis, and mild autonomic nerve degeneration. In this study conducted on mice, findings indicate the potential for chronic persistence of SARS-CoV-2 in the lungs one year post initial mild or asymptomatic infection, which could suggest the possibility of recurrent episodes in similar human conditions. The observed thickening of alveolar walls and potential fibrotic areas in these mice may imply an increased risk of post-COVID fibrosis in humans. Furthermore, the presence of SARS-CoV-2-positive inflammatory cells in some asymptomatic murine cases could herald a progression toward ongoing inflammation and chronic lung disease in humans. Therefore, the necessity for further studies in human subjects and vigilant monitoring of high-risk human populations is underscored.

Investigaciones anteriores sobre COVID-19 o COVID prolongado se centraron principalmente en la presencia de SARS-CoV-2 principalmente en pacientes sintomáticos. Este estudio tuvo como objetivo investigar la persistencia del SARS-CoV-2 después de 1 año de COVID-19 asintomático o leve. Se estudiaron ratones transgénicos K18-hACE2 infectados con SARS-CoV-2 y de control (n=25). Los animales con síntomas moderados y graves se sacrificaron después de ocho días, mientras que los ratones con síntomas leves o asintomáticos se mantuvieron en BSL-III durante doce meses. Los análisis incluyeron estado general, histoquímica, inmunohistoquímica, microscopía electrónica de transmisión y qRT- PCR. Los pulmones del grupo de doce meses mostraron engrosamiento de las paredes alveolares, y algunos pulmones exhibieron reclutamiento de células inflamatorias, presencia de ARNm del SARS-CoV-2, inmunopositividad para la proteína de la espícula del SARS-CoV-2 y TEM mostró virus (60 -125 nm) dentro de las vesículas, lo que indica una replicación continua. Ciertas muestras de pulmón mostraron una presencia persistente de SARS- CoV-2 en exocrinocitos bronquiolares, células endoteliales y macrófagos. El grupo de ocho días presentó neumonitis intersticial viral, inmunopositividad al SARS-CoV-2 y ARNm. Los corazones de ocho días mostraron ARNm viral, mientras que los corazones de doce meses dieron negativo. Algunos animales asintomáticos de doce meses presentaron disminución del surfactante, engrosamiento de la membrana basal, fibrosis y degeneración leve del nervio autónomo. En este estudio realizado en ratones, los hallazgos indican la posibilidad de persistencia crónica del SARS-CoV-2 en los pulmones un año después de la infección inicial leve o asintomática, lo que podría sugerir la posibilidad de episodios recurrentes en condiciones humanas similares. El engrosamiento observado de las paredes alveolares y las posibles áreas fibróticas en estos ratones puede implicar un mayor riesgo de fibrosis post-COVID en humanos. Además, la presencia de células inflamatorias positivas para SARS- CoV-2 en algunos casos murinos asintomáticos podría presagiar una progresión hacia una inflamación continua y una enfermedad pulmonar crónica en humanos. Por lo tanto, se subraya la necesidad de realizar más estudios en seres humanos y realizar un seguimiento atento de las poblaciones humanas de alto riesgo.

Associations between the social environment and early childhood developmental outcomes of Puerto Rican children with prenatal Zika virus exposure: a cross-sectional study.

BACKGROUND: Prenatal exposure to the Zika virus can lead to microcephaly and adverse developmental outcomes, even in children without evident birth defects. The social environment plays a crucial role in infant health and developmental trajectories, especially during periods of heightened brain plasticity. The study aimed to assess socioenvironmental factors as predictors of developmental outcomes of 36-month-old children exposed to Zika virus prenatally. STUDY DESIGN: This cross-sectional study included 53 mothers and 55 children enrolled in the Pediatric Outcomes of Prenatal Zika Exposure cohort study in Puerto Rico. The study performs follow-up developmental assessments of children born to mothers with confirmed and probable Zika virus infection during pregnancy. Mothers completed socioenvironmental questionnaires (e.g., Perceived Neighborhood Scale and US Household Food Insecurity Survey). Children's developmental outcomes were assessed with the Bayley Scales of Infant and Toddler Development: Third Edition, the Ages and Stages Questionnaires: Third Edition, the Ages and Stages Questionnaire-Socioemotional: Second Edition, and the Child Adjustment and Parent Efficacy Scale. RESULTS: Linear regression models, adjusting for a child's sex and age and maternal education, revealed that early life exposure to food insecurity and maternal pregnancy stressors were significantly associated with poorer developmental outcomes in Zika virus-exposed children at 36 months of age. Maternal resilience representation of adaptive ability was associated with the preservation of adequate developmental outcomes in children. CONCLUSIONS: Pregnancy and early childhood are critical life periods for ensuring optimal brain development in children. While the mechanisms in the interaction of children with their environment are complex, the risk and protective factors identified in the study are modifiable through public policy and preventive initiatives. Implementation of comprehensive strategies that improve access to social support programs, educational and nutritional interventions, and mental health services during pregnancy and early childhood can enhance the developmental potential of vulnerable children.

Molecular detection of ovine gammaherpesvirus 2 in free ranging wild boars (Sus scrofa) from Southern Brazil.

Ovine gammaherpesvirus 2 (OvGHV2) is a member of Macavirus genus, subfamily Gammaherpesvirinae, family Herpesviridae, and causes sheep associated-malignant catarrhal fever (SA-MCF) in a wide range of ungulates. However, no descriptions of SA-MCF and/or infections due to OvGHV2 were identified in the wild boar (Sus scrofa). This study investigated the occurrence of OvGHV2 in the lungs (n = 44) of asymptomatic, free ranging wild boars captured in several regions of Paraná State, Southern Brazil. A PCR assay targeting the OvGHV2 tegument protein gene amplified OvGHV2 DNA in 4.55% (2/44) of the pulmonary tissues evaluated. Sequence analysis confirmed that the OvGHV2 strains herein identified have 98.4% deduced amino acid (aa) sequence identity with the prototype strain of OvGHV2 and 96.4-100% aa identity with similar strains of OvGHV2 detected in several animal species from diverse countries. These findings confirmed that these two wild boars were infected by OvGHV2, represent the first description of this infection in these animals, and add to the number of pathogens identified in this animal species. Furthermore, these findings contrast earlier descriptions of OvGHV2 in swine since in all previous reports the infected pigs demonstrated clinical manifestations of disease. Consequently, these wild boars from Southern Brazil were subclinically infected or suffered asymptomatic infections by OvGHV2.

Detection of plasma anti-lipopolysaccharide (LPS)antibodies against enterohemorrhagic Escherichia coli(EHEC) in asymptomatic kindergarten teachers fromBuenos Aires province

Resumen En Argentina, el síndrome urémico hemolítico causado por Escherichia coli enterohemorrágica (EHEC) tiene la más alta incidencia del mundo. Las infecciones por EHEC tienen un comportamiento endemoepidémico y causan del 20 al 30% de los síndromes de diarrea sanguinolenta en niños menores de 5 años. En el período 2016-2020, se notificaron 272 nuevos casos por año al Sistema de Vigilancia de Salud Nacional. Múltiples factores son responsables de la alta incidencia de SUH en Argentina, incluyendo la transmisión persona-persona. Con el objetivo de detectar posibles portadores asintomáticos de EHEC, realizamos un estudio preliminar de la frecuencia de anticuerpos antilipopolisacáridos contra los serotipos de EHEC más prevalentes en Argentina. El estudio se realizó con muestras de plasma obtenidas de 61 maestras y maestros de jardines de infantes de 26 instituciones del distrito de José C. Paz, localizado en el área suburbana de la provincia de Buenos Aires, Argentina. El 51% de las muestras presentaron anticuerpos contra los serotipos de lipopolisacáridos O157, O145, O121 y O103; el 6,4% de las muestras positivas tuvieron el isotipo IgM (n=2), el 61,3% el isotipo IgG (n=19) y el 32,3% los isotipos IgM e IgG (n=10). Dado que los anticuerpos antilipopolisacáridos presentan usualmente una duración corta, la detección de IgM específica podría indicar una infección reciente. Además, el alto porcentaje de muestras positivas hallado podría indicar una exposición frecuente a las cepas de EHEC en la cohorte estudiada. Asimismo, la gran población de adultos portadores asintomáticos de estas cepas patógenas podría contribuir al comportamiento endémico, a través de la transmisión persona-persona. El perfeccionamiento de programas educacionales continuos en jardines de infantes podría constituir una medida importante para reducir los casos de síndrome urémico hemolítico, no solo en Argentina, sino también en el mundo.

Abstract In Argentina, hemolytic uremic syndrome (HUS) caused by EHEC has the highest incidence in the world. EHEC infection has an endemo-epidemic behavior, causing 20-30% of acute bloody diarrhea syndrome in children under 5 years old. In the period 2016-2020, 272 new cases per year were notified to the National Health Surveillance System. Multiple factors are responsible for HUS incidence in Argentina including person-to-person transmission. In order to detect possible EHEC carriers, we carried out a preliminary study of the frequency of kindergarten teachers with anti-LPS antibodies against the most prevalent EHEC serotypes in Argentina. We analyzed 61 kindergarten teachers from 26 institutions from José C. Paz district, located in the suburban area of Buenos Aires province, Argentina. Fifty-one percent of the plasma samples had antibodies against O157, O145, O121 and O103 LPS: 6.4% of the positive samples had IgM isotype (n=2), 61.3% IgG isotype (n=19) and 32.3% IgM and IgG (n=10). Given that antibodies against LPS antigens are usually short-lived specific IgM detection may indicate a recent infection. In addition, the high percentage of positive samples may indicate a frequent exposure to EHEC strains in the cohort studied, as well as the existence of a large non-symptomatic population of adults carrying pathogenic strains that could contribute to the endemic behavior through person-to-person transmission. The improvement of continuous educational programs in kindergarten institutions could be a mandatory measure to reduce HUS cases not only in Argentina but also globally.

Comparative analysis of asymptomatic infection prevalence in Beta, Delta, and Omicron surges of COVID-19.

BACKGROUND: The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has had a devastating impact on the global population, with an estimated 650 million people infected and more than 6.6 million lives lost. Asymptomatic individuals have been shown to play a significant role in the transmission of the virus. Therefore, this study aims to investigate and compare the prevalence of asymptomatic individuals across three waves associated with the Beta, Delta, and Omicron variants of the virus. METHODS: This retrospective study was conducted between December 2020 and March 2022. The study population consisted of passengers on international flights who were referred to the Gerash Clinical and Molecular Diagnosis Laboratory. Real-time PCR was employed for the diagnosis of SARS-CoV-2. RESULTS: Out of a total of 8592 foreign travelers referred to our laboratory, 139 (1.16 %) tested positive for SARS-CoV-2 infection and were asymptomatic. During the Beta surge, 35 (1.49 %) out of 2335 passengers tested positive for SARS-CoV-2. In the Delta surge, 31 (0.6 %) out of 5127 passengers tested positive. However, during the Omicron surge, a significantly higher number of passengers, specifically 73 (6.46 %) out of 1130, had a positive result for the SARS-CoV-2 test. CONCLUSION: Considering the significant role of asymptomatic transmission in the spread of COVID-19, it is imperative to reconsider health policies when dealing with future surges of the Omicron subvariants. Additionally, we strongly recommend that the World Health Organization prioritize the development and distribution of second-generation vaccines that target not only disease but also infection prevention.

Detection of plasma anti-lipopolysaccharide (LPS) antibodies against enterohemorrhagic Escherichia coli (EHEC) in asymptomatic kindergarten teachers from Buenos Aires province.

In Argentina, hemolytic uremic syndrome (HUS) caused by EHEC has the highest incidence in the world. EHEC infection has an endemo-epidemic behavior, causing 20-30% of acute bloody diarrhea syndrome in children under 5 years old. In the period 2016-2020, 272 new cases per year were notified to the National Health Surveillance System. Multiple factors are responsible for HUS incidence in Argentina including person-to-person transmission. In order to detect possible EHEC carriers, we carried out a preliminary study of the frequency of kindergarten teachers with anti-LPS antibodies against the most prevalent EHEC serotypes in Argentina. We analyzed 61 kindergarten teachers from 26 institutions from José C. Paz district, located in the suburban area of Buenos Aires province, Argentina. Fifty-one percent of the plasma samples had antibodies against O157, O145, O121 and O103 LPS: 6.4% of the positive samples had IgM isotype (n=2), 61.3% IgG isotype (n=19) and 32.3% IgM and IgG (n=10). Given that antibodies against LPS antigens are usually short-lived specific IgM detection may indicate a recent infection. In addition, the high percentage of positive samples may indicate a frequent exposure to EHEC strains in the cohort studied, as well as the existence of a large non-symptomatic population of adults carrying pathogenic strains that could contribute to the endemic behavior through person-to-person transmission. The improvement of continuous educational programs in kindergarten institutions could be a mandatory measure to reduce HUS cases not only in Argentina but also globally.

Viable Leishmania parasites in the absence of an in vitro IFN-γ response in asymptomatic carriers

ABSTRACT Asymptomatic infection (the absence or inapparent signs and symptoms) has been observed in many endemic areas of leishmaniasis, however, little is known about the parasitological and immunological factors associated with this type of infection. This study aimed to identify the in vitro expression of IFN-γ in asymptomatic carriers of viable Leishmania parasites. Asymptomatic infection was identified using the Montenegro skin test in an at-risk population from Yucatan, Mexico. Parasite viability was evinced in the blood by 7SL RNA transcripts amplification. The expression of mRNA IFN-γ was analyzed in peripheral blood mononuclear cells stimulated with soluble Leishmania antigen, using RT-qPCR. Parasite viability was observed in 33.3 % (5/15) of asymptomatic subjects. No differences were found in the expression of IFN-γ between asymptomatic and healthy subjects, and no correlation was found between the presence of viable parasites and the expression of IFN-γ. This study demonstrates the persistence of Leishmania parasites in the absence of an in vitro IFN-γ response in asymptomatic carriers from Mexico.

Comparative analysis of asymptomatic infection prevalence in Beta, Delta, and Omicron surges of COVID-19

Abstract Background The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has had a devastating impact on the global population, with an estimated 650 million people infected and more than 6.6 million lives lost. Asymptomatic individuals have been shown to play a significant role in the transmission of the virus. Therefore, this study aims to investigate and compare the prevalence of asymptomatic individuals across three waves associated with the Beta, Delta, and Omicron variants of the virus. Methods This retrospective study was conducted between December 2020 and March 2022. The study population consisted of passengers on international flights who were referred to the Gerash Clinical and Molecular Diagnosis Laboratory. Real-time PCR was employed for the diagnosis of SARS-CoV-2. Results Out of a total of 8592 foreign travelers referred to our laboratory, 139 (1.16 %) tested positive for SARS-CoV-2 infection and were asymptomatic. During the Beta surge, 35 (1.49 %) out of 2335 passengers tested positive for SARS-CoV-2. In the Delta surge, 31 (0.6 %) out of 5127 passengers tested positive. However, during the Omicron surge, a significantly higher number of passengers, specifically 73 (6.46 %) out of 1130, had a positive result for the SARS-CoV-2 test. Conclusion Considering the significant role of asymptomatic transmission in the spread of COVID-19, it is imperative to reconsider health policies when dealing with future surges of the Omicron subvariants. Additionally, we strongly recommend that the World Health Organization prioritize the development and distribution of second-generation vaccines that target not only disease but also infection prevention.

Bacterial profile and prevalence of urinary tract infections in pregnant women in Latin America: a systematic review and meta-analysis.

BACKGROUND: Given the physiological changes during pregnancy, pregnant women are likely to develop recurrent urinary tract infections (UTIs) and pyelonephritis, which may result in adverse obstetric outcomes, including prematurity and low birth weight preeclampsia. However, data on UTI prevalence and bacterial profile in Latin American pregnant women remain scarce, necessitating the present systematic review to address this issue. METHODS: To identify eligible observational studies published up to September 2022, keywords were systematically searched in Medline/PubMed, Cochrane Library, Embase, Web of Science, and Bireme/Lilacs electronic databases and Google Scholar. The systematic review with meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and the quality of studies was classified according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. The meta-analysis employed a random-effects method with double-arcsine transformation in the R software. RESULTS: Database and manual searches identified 253,550 citations published until September 2022. Among the identified citations, 67 met the inclusion criteria and were included in the systematic review, corresponding to a sample of 111,249 pregnant women from nine Latin American countries. Among Latin American pregnant women, the prevalence rates of asymptomatic bacteriuria, lower UTI, and pyelonephritis were estimated at 18.45% (95% confidence interval [CI]: 15.45-21.53), 7.54% (95% CI: 4.76-10.87), and 2.34% (95% CI: 0.68-4.85), respectively. Some regional differences were also detected. Among the included studies, Escherichia coli (70%) was identified as the most frequently isolated bacterial species, followed by Klebsiella sp. (6.8%). CONCLUSION: Pregnant women in Latin America exhibit a higher prevalence of bacteriuria, UTI, and pyelonephritis than pregnant women globally. This scenario reinforces the importance of universal screening with urine culture during early prenatal care to ensure improved outcomes. Future investigations should assess the microbial susceptibility profiles of uropathogens isolated from pregnant women in Latin America. TRIAL REGISTRATION: This research was registered at PROSPERO (No. CRD42020212601).

Evaluation of Proinflammatory Chemokines in HIV Patients with Asymptomatic Leishmania Infantum Infection.

Asymptomatic Leishmania infantum, when associated with HIV, can become severe and potentially fatal. In this co-infection, the worst prognosis may be influenced by the host's immunological aspects, which are crucial in determining susceptibility. Chemokines play an important role in this process by influencing the cellular composition at affected sites and impacting the disease's outcome. Therefore, the aim of this study was to evaluate proinflammatory chemokines in HIV patients with the asymptomatic L. infantum infection. In this cross-sectional study, the levels of CCL2, CCL5, CXCL8, MIG, and IP-10 were measured in 160 serum samples from co-infected patients (n = 53), patients with HIV (n = 90), and negative controls (n = 17). Quantification was determined by flow cytometry. The obtained data were statistically analyzed using the Kruskal-Wallis test, followed by the Dunn's post-test and the Spearman's correlation coefficient. Significance was set at p < 0.05. The chemokines CCL2, CCL5, MIG, and IP-10 exhibited higher levels in the HIV group compared to co-infection. However, the elevated levels of all these chemokines and their increased connectivity in co-infected patients appear to be important in identifying proinflammatory immune responses associated with the asymptomatic condition. Furthermore, a weak negative correlation was observed between higher levels of CXCL8 and lower viral loads in co-infected patients.

Epidemiological and Genomic Analysis of Asymptomatic SARS-CoV-2 Infections during the Delta and Omicron Epidemic Waves in São Paulo City, Brazil.

We examined the asymptomatic rates of SARS-CoV-2 infection during the Delta and Omicron waves in the city of São Paulo. Nasopharyngeal swabs were collected at strategic points of the city (open-air markets, bus terminals, airports) for SARS-CoV-2 RNA testing. Applying the questionnaire, the symptomatic individuals were excluded, and only asymptomatic cases were analyzed. During the Delta wave, a total of 4315 samples were collected, whereas 2372 samples were collected during the first Omicron wave. The incidence of the asymptomatic SARS-CoV-2 infection was 0.6% during the Delta wave and 0.8% during the Omicron wave. No statistical differences were found in the threshold amplification cycle. However, there was a statistical difference observed in the sublineage distribution between asymptomatic and symptomatic individuals. Our study determined the incidence of asymptomatic infection by monitoring individuals who remained symptom-free, thereby providing a reliable evaluation of asymptomatic SARS-CoV-2 carriage. Our findings reveal a relatively low proportion of asymptomatic cases, which could be attributed to our rigorous monitoring protocol for the presence of clinical symptoms. Investigating asymptomatic infection rates is crucial to develop and implement effective disease control strategies.

Why are so many enteric pathogen infections asymptomatic? Pathogen and gut microbiome characteristics associated with diarrhea symptoms and carriage of diarrheagenic E. coli in northern Ecuador.

A high proportion of enteric infections, including those caused by diarrheagenic Escherichia coli (DEC), are asymptomatic for diarrhea. The factors responsible for the development of diarrhea symptoms, or lack thereof, remain unclear. Here, we used DEC isolate genome and whole stool microbiome data from a case-control study of diarrhea in Ecuador to examine factors associated with diarrhea symptoms accompanying DEC carriage. We investigated i) pathogen abundance, ii) gut microbiome characteristics, and iii) strain-level pathogen characteristics from DEC infections with diarrhea symptoms (symptomatic infections) and without diarrhea symptoms (asymptomatic infections). We also included data from individuals with and without diarrhea who were not infected with DEC (uninfected cases and controls). i) E. coli relative abundance in the gut microbiome was highly variable, but higher on-average in individuals with symptomatic compared to asymptomatic DEC infections. Similarly, the number and relative abundances of virulence genes in the gut were higher in symptomatic than asymptomatic DEC infections. ii) Measures of microbiome diversity were similar regardless of diarrhea symptoms or DEC carriage. Proteobacterial families that have been described as pathobionts were enriched in symptomatic infections and uninfected cases, whereas potentially beneficial taxa, including the Bacteroidaceae and Bifidobacteriaceae, were more abundant in individuals without diarrhea. An analysis of high-level gene functions recovered in metagenomes revealed that genes that were differentially abundant by diarrhea and DEC infection status were more abundant in symptomatic than asymptomatic DEC infections. iii) DEC isolates from symptomatic versus asymptomatic individuals showed no significant differences in virulence or accessory gene content, and there was no phylogenetic signal associated with diarrhea symptoms. Together, these data suggest signals that distinguish symptomatic from asymptomatic DEC infections. In particular, the abundance of E. coli, the virulence gene content of the gut microbiome, and the taxa present in the gut microbiome have an apparent role.

Optimal practices for the management of hereditary transthyretin amyloidosis: real-world experience from Japan, Brazil, and Portugal.

Hereditary transthyretin (ATTRv) amyloidosis is a rare and autosomal dominant disorder associated with mutations in the transthyretin gene. Patients present with diverse symptoms related to sensory, motor, and autonomic neuropathy, as well as gastrointestinal, ocular, cardiac, renal and orthopedic symptoms, resulting from the deposition of transthyretin amyloid fibrils in multiple organs. The progressive nature of ATTRv amyloidosis necessitates pre- and post-onset monitoring of the disease. This review article is primarily based on a collation of discussions from a medical advisory board meeting in August 2021. In this article, we summarize the best practices in amyloidosis centers in three major endemic countries for ATTRv amyloidosis (Japan, Brazil, and Portugal), where most patients carry the Val30Met mutation in the transthyretin gene and the patients' genetic background was proven to be the same. The discussions highlighted the similarities and differences in the management of asymptomatic gene mutation carriers among the three countries in terms of the use of noninvasive tests and tissue biopsies and timing of starting the investigations. In addition, this article discusses a set of practical tests and examinations for monitoring disease progression applicable to neurologists working in diverse medical settings and generalizable in non-endemic countries and areas. This set of assessments consists of periodic (every 6 to 12 months) evaluations of patients' nutritional status and autonomic, renal, cardiac, ophthalmologic, and neurological functions. Physical examinations and patient-reported outcome assessments should be also scheduled every 6 to 12 months. Programs for monitoring gene mutation carriers and robust referral networks can aid in appropriate patient management in pre- to post-onset stages. For pre- and post-symptom onset testing for ATTRv amyloidosis, various noninvasive techniques are available; however, their applicability differs depending on the medical setting in each country and region, and the optimal option should be selected in view of the clinical settings, medical environment, and available healthcare resources in each region.

Age, Gender, Body Mass Index, and Foot Loading During Gait.

Background: The aim was to analyze changes in normal functional parameters of gait analysis by aging, sex, and body mass index (BMI). Methods: A cross-sectional study with a consecutive sample of asymptomatic subjects was performed between 2014 and 2020. Primary outcomes were time and force parameters (contact time and center of force [CoF] time), in the heel, midfoot, and metatarsal areas, measured using an in-office force platform. Results: A total of 156 subjects (312 feet) were included, including 67% of women with a mean age of 47 years. The mean of total contact time was similar in males and females (P = .695) and across BMI (P = .413). Contact time did not show differences by region (P = .648 heel, P = .286 midfoot, and P = .690 metatarsal). CoF time in the heel and metatarsal areas did not change between males and females (P = .288 and P = .879, respectively); meanwhile, it was different in midfoot (P = .002). Maximum force showed a reduction between sexes in the heel (P = .039) but did not in the midfoot and metatarsal areas. By age, differences were detected in the heel and metatarsal areas in females (P = .002 and P = .001) and the metatarsal area in males (P = .001). According to the age groups, total contact time increased in females (P = .001) but not in males (P = .018), and no differences were detected between foot areas. In females, CoF time did not change either foot areas or age groups. In males, CoF time values increased in the midfoot area in the older group (P = .001). Conclusion: Time variables did not change by foot region, independent of age, sex, and BMI. Heel maximum force decreased in females, probably linked to adaptive phenomena by aging. The midfoot remains stable, and acts as an undamaged "bridge." These parameters could be interpreted as normal in asymptomatic subjects. Level of Evidence: Level III, diagnostic and prognostic.

Molecular characterization and genotyping of isolates from cancer patients with Clostridioides difficile infection or asymptomatic colonization.

Introduction. Cancer patients with Clostridioides difficile infection (CDI) are at a higher risk for adverse outcomes. In addition, a high prevalence of Clostridioides difficile asymptomatic colonization (CDAC) has been reported in this vulnerable population.Gap Statement. The molecular characteristics and potential role of CDAC in healthcare-related transmission in the cancer population have been poorly explored.Aim. We aimed to compare the molecular and genotypic characteristics of C. difficile isolates from cancer patients with CDAC and CDI.Method. We conducted a prospective cohort study of cancer patients with CDAC or CDI from a referral centre. Molecular characterization, typification and tcdC gene expression of isolates were performed.Results. The hospital-onset and community-onset healthcare facility-associated CDI rates were 4.5 cases/10 000 patient-days and 1.4 cases/1 000 admissions during the study period. Fifty-one C. difficile strains were isolated: 37 (72 %) and 14 (28 %) from patients with CDI or CDAC, respectively. All isolates from symptomatic patients were tcdA+/tcdB+, and four (10 %) were ctdA+/ctdB+. In the CDAC group, 10 (71 %) isolates were toxigenic, and none were ctdA+/ctdB+. The Δ18 in-frame tcdC deletion and two transition mutations were found in five isolates. After bacterial typing, 60 % of toxigenic isolates from asymptomatic carriers were clonal to those from patients with C. difficile-associated diarrhoea. No NAP1/027/BI strains were detected.Conclusions. We found a clonal association between C. difficile isolates from patients with CDAC and CDI. Studies are needed to evaluate the potential role of asymptomatic carriers in the dynamics of nosocomial transmission to support infection control measures and reduce the burden of CDI in high-risk groups.

Indications for carotid Doppler ultrasound in asymptomatic patients - are we ordering it correctly?

Background: Carotid arteries are frequently the site of pathologies, the most common being atherosclerosis, which may result in the formation of plaques, causing stenosis. Doppler ultrasound is currently the exam of choice for assessment of the carotid arteries in asymptomatic patients to screen for and diagnose vascular lesions. Current guidelines recommend screening patients who have risk factors for carotid stenosis and who are able and willing to undergo medical treatment and/or carotid intervention. Screening asymptomatic patients in the general adult population who have no significant risk factors is not recommended. Objectives: To assess whether medical experts rely on the literature to request Doppler ultrasound for screening. Methods: A retrospective selection of patients was performed based on requests for carotid ultrasound. The data collected were computed and analyzed using RStudio version 1.3.959. Results: The request was evaluated as appropriate as long as the patients presented at least one risk factor for carotid plaques. Fifty-five out of 152 patients met criteria for carotid screening. The most frequent indication in the study population was vascular check-up. Arterial hypertension was the most prevalent risk factor. Vascular surgery specialists were more likely to order the exam correctly (odds ratio for correct indications: 3.52 [CI 1.14 - 10.87], with p=0.02). The rate of correct Doppler ultrasound requests was 36% (95%CI 29 to 42%). Conclusions: An excess of requests for carotid ultrasound screening was found in this study. Vascular surgeons more often requested the test correctly.