Publications by authors named "Maritza Calderon"

Toxoplasma gondii infection can pose a significant health risk, particularly among immunocompromised individuals, such as people living with HIV (PLHIV). This study aimed to evaluate the seroprevalence of T. gondii and associated factors among PLHIV and individuals who are HIV negative in two distinct regions of Peru: Iquitos and Lima.

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is a ubiquitous zoonotic protozoan parasite that infects a wide variety range of warm-blooded animals. This study describes the epidemiological scenario of in an indigenous community that relies on subsistence hunting in a well-conserved and isolated area of the Peruvian Amazon. The high seropositivity against in humans (83.

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Children living in low-resource settings are frequently gut-colonized with multidrug-resistant bacteria. We explored whether breastfeeding may protect against children's incident gut colonization with extended-spectrum beta-lactamase-producing (ESBL-) and , , or spp. (ESBL-KEC).

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Tuberculosis remains one of the leading causes of death worldwide, especially in low- and middle-income countries. Tuberculosis treatment and control efforts are hindered by the difficulty in making the diagnosis, as currently available diagnostic tests are too slow, too expensive, or not sufficiently sensitive. Recombinase polymerase amplification (RPA) is a novel technique that allows for the amplification of DNA rapidly, at constant temperature, and with minimal expense.

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Article Synopsis
  • * Researchers evaluated 140 participants using both traditional methods (qPCR and cryptococcal antigen tests) and advanced techniques (metagenomic next-generation sequencing) to identify infections like cerebral toxoplasmosis and cryptococcal meningitis.
  • * Results showed that only 34% were diagnosed with an infection using any method, indicating the need for improved diagnostic tests to better detect central nervous system infections in this vulnerable population.
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Congenital transmission of Trypanosoma cruzi is an important source of new Chagas infections worldwide. The mechanisms of congenital transmission remain poorly understood, but there is evidence that parasite factors are involved. Investigating changes in parasite strain diversity during transmission could provide insight into the parasite factors that influence the process.

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Objectives.: To evaluate the variation of hematological profiles of patients infected with uncomplicated Plasmodium vivax (Pv) and P. falciparum (Pf) malaria before, during and after treatment in a population of the Loreto region.

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Poultry farming represents Peru's primary food animal production industry, where antimicrobial growth promoters are still commonly used, exerting selective pressure on intestinal microbial populations. Consumption and direct animal-to-human transmission have been reported, and farmworkers are at high risk of colonization with resistant bacteria. We conducted a cross-sectional survey among 54 farmworkers to understand their current antimicrobial resistance (AMR) awareness in Ica, Peru.

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Article Synopsis
  • * Researchers used advanced sequencing tools to analyze a specific gene from blood samples of HIV patients showing high levels of the parasite.
  • * They found diverse strains of the parasite within individual patients, which helps understand the genetic variation of the infection and its effects on disease severity.
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The widespread and poorly regulated use of antibiotics in animal production in low- and middle-income countries (LMICs) is increasingly associated with the emergence and dissemination of antibiotic resistance genes (ARGs) in retail animal products. Here, we compared from chickens and humans with varying levels of exposure to chicken meat in a low-income community in the southern outskirts of Lima, Peru. We hypothesize that current practices in local poultry production result in highly resistant commensal bacteria in chickens that can potentially colonize the human gut.

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Toxoplasma gondii is an important foodborne pathogen worldwide, with undercooked meat as the main source of human transmission. In this study, we determined the seroprevalence of T. gondii in free-range pigs from two adjacent villages in the Tumbes region of northern Peru, El Tutumo and Nuevo Progreso.

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Article Synopsis
  • Diagnosing toxoplasmic encephalitis (TE) is difficult due to limited testing options, especially in low-resource settings, leading many clinicians to rely on empirical treatments.
  • A novel urine diagnostic method using specially dyed nanoparticles significantly enhances the detection of T. gondii antigens, achieving a detection limit of 7.8pg/ml for GRA1 and 31.3pg/ml for SAG1.
  • The study suggests that the new test shows good specificity for TE, particularly with GRA1, and indicates potential for noninvasive diagnosis using nanoparticle technology.
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Capacity building in public health is an urgent global priority. Recently, there has been an increasing emphasis on South-South and triangular cooperation. We describe our experience with a public health training collaboration between Peru and Bolivia, with Peru providing capacity building and expertise to Bolivia, while receiving supportive funding and training from the United States.

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The leading animal model of experimental Chagas disease, the mouse, plays a significant role in studies for vaccine development, diagnosis, and human therapies. Humans, along with Old World primates, alone among mammals, cannot make the terminal carbohydrate linkage of the α-Gal trisaccharide. It has been established that the anti-α-Gal immune response is likely to be a critical factor for protection against () infection in humans.

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BACKGROUNDSerological tools for the accurate detection of recent malaria exposure are needed to guide and monitor malaria control efforts. IgG responses against Plasmodium vivax and P. falciparum merozoite surface protein-10 (MSP10) were measured as a potential way to identify recent malaria exposure in the Peruvian Amazon.

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Feeding of infant formula using contaminated bottles may be an important transmission pathway of enteric pathogens during early life. Determinants of suboptimal bottle hygiene and the feasibility and acceptability of intervention strategies have not been well assessed. We evaluated the extent of bottle contamination, its contributing factors, and options for promoting improved bottle hygiene in a Peruvian shantytown.

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Quantitative polymerase chain reaction (qPCR) for multicopy genes has emerged as a promising strategy for sensitive detection of parasite DNA. qPCR can be performed from blood samples, which are minimally invasive to collect. However, there is no consensus about what type of blood specimen yields the best sensitivity.

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Diagnosis of clinical toxoplasmosis remains a challenge, thus limiting the availability of human clinical samples. Though murine models are an approximation of human response, their definitive infection status and tissue availability make them critical to the diagnostic development process. Hydrogel mesh nanoparticles were used to concentrate antigen to detectable levels for mass spectrometry.

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Background: Detection of Trypanosoma cruzi antigens in clinical samples is considered an important diagnostic tool for Chagas disease. The production and use of polyclonal antibodies may contribute to an increase in the sensitivity of immunodiagnosis of Chagas disease.

Methodology/principal Findings: Polyclonal antibodies were raised in alpacas, rabbits, and hens immunized with trypomastigote excreted-secreted antigen, membrane proteins, trypomastigote lysate antigen and recombinant 1F8 to produce polyclonal antibodies.

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Article Synopsis
  • - The study investigates the rising malaria incidence in the Peruvian Amazon, focusing on the role of asymptomatic and submicroscopic carriers of Plasmodium parasites in maintaining malaria transmission in areas with low endemicity.
  • - Through blood sampling and advanced diagnostic techniques, the research found that P. vivax infections were significantly underreported when using traditional microscopy, with a prevalence of 25.1% by PCR compared to just 3.6% by microscopy.
  • - Risk factors identified include higher likelihood of P. vivax infection among older individuals, recent settlers, and those seropositive for the parasite, while P. falciparum infections were more common in younger individuals and those with previous infections.
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Plasmodium vivax is the most prevalent cause of human malaria in the world and can lead to severe disease with high potential for relapse. Its genetic and geographic diversities make it challenging to control. P.

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Antibiotic-resistant infections annually claim hundreds of thousands of lives worldwide. This problem is exacerbated by exchange of resistance genes between pathogens and benign microbes from diverse habitats. Mapping resistance gene dissemination between humans and their environment is a public health priority.

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Human sapovirus has been shown to be one of the most important etiologies in pediatric patients with acute diarrhea. However, very limited data are available about the causative roles and epidemiology of sapovirus in community settings. A nested matched case-control study within a birth cohort study of acute diarrhea in a peri-urban community in Peru from 2007 to 2010 was conducted to investigate the attributable fraction (AF) and genetic diversity of sapovirus.

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Trypanosoma cruzi, the etiologic agent of Chagas disease, is transmitted by hematophagous reduviid bugs within the subfamily Triatominae. These vectors take blood meals from a wide range of hosts, and their feeding behaviors have been used to investigate the ecology and epidemiology of T. cruzi.

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