Characterization of antigenic proteins of the Taenia solium postoncospheral form.

Neurocysticercosis is the leading cause for acquired epilepsy worldwide, and it is caused by the larval stage of the parasite Taenia solium. Several proteins of this stage have been characterized and studied to understand the parasite-host interaction, however, the proteins from the early cysticercus stages (the postoncospheral form) have not yet been characterized. The study of the postoncospheral form proteins is important to understand the host-parasite relationship in the early stages of infection. The aim of this work was to identify postoncospheral form antigenic proteins using sera from neurocysticercosis patients. T. solium activated oncospheres were cultured in HCT-8 cells to obtain the postoncospheral form. Soluble total and excretory/secretory proteins were obtained from the postoncospheral form and were incubated with both pool sera and individual serum of neurocysticercosis positive human patients. Immunoblotting showed target antigenic proteins with apparent molecular weights of 23 kDa and 46-48 kDa. The 46-48 kDa antigen bands present in soluble total and excretory/secretory postoncospheral form proteins were analyzed by LC-MS/MS; proteins identified were: nuclear elongation factor 1 alpha, enolase, unnamed protein product/antigen diagnostic GP50, calcium binding protein calreticulin precursor and annexin. The postoncospheral form expresses proteins related to interaction with the host, some of these proteins are predicted to be exosomal proteins. In conclusion, postoncospheral proteins are consistent targets of the humoral immune response in human and may serve as targets for diagnosis and vaccines.

Building a framework to decolonize global emergency medicine.

Background: Global emergency medicine (GEM) is situated at the intersection of global health and emergency medicine (EM), which is built upon a history of colonial systems and institutions that continue to reinforce inequities between high-income countries (HICs) and low- and middle-income countries (LMICs) today. These power imbalances yield disparities in GEM practice, research, and education. Approach: The Global Emergency Medicine Academy (GEMA) of the Society for Academic Emergency Medicine formed the Decolonizing GEM Working Group in 2020, which now includes over 100 worldwide members. The mission is to address colonial legacies in GEM and catalyze sustainable changes and recommendations toward decolonization at individual and institutional levels. To develop recommendations to decolonize GEM, the group conducted a nonsystematic review of existing literature on decolonizing global health, followed by in-depth discussions between academics from LMICs and HICs to explore implications and challenges specific to GEM. We then synthesized actionable solutions to provide recommendations on decolonizing GEM. Results: Despite the rapidly expanding body of literature on decolonizing global health, there is little guidance specific to the relatively new field of GEM. By applying decolonizing principles to GEM, we suggest key priorities for improving equity in academic GEM: (1) reframing partnerships to place LMIC academics in positions of expertise and power, (2) redirecting research funding toward LMIC-driven projects and investigators, (3) creating more equitable practices in establishing authorship, and (4) upholding principles of decolonization in the education of EM trainees from LMICs and HICs. Conclusions: Understanding the colonial roots of GEM will allow us to look more critically at current health disparities and identify inequitable institutionalized practices within our profession that continue to uphold these misguided concepts. A decolonized future of GEM depends on our recognition and rectification of colonial-era practices that shape structural determinants of health care delivery and scientific advancement.

Understanding the pathogenic mechanisms and therapeutic effects in neurocysticercosis.

Despite being a leading cause of acquired seizures in endemic regions, the pathological mechanisms of neurocysticercosis are still poorly understood. This study aims to investigate the impact of anthelmintic treatment on neuropathological features in a rat model of neurocysticercosis. Rats were intracranially infected with Taenia solium oncospheres and treated with albendazole + praziquantel (ABZ), oxfendazole + praziquantel (OXF), or untreated placebo (UT) for 7 days. Following the last dose of treatment, brain tissues were evaluated at 24 h and 2 months. We performed neuropathological assessment for cyst damage, perilesional brain inflammation, presence of axonal spheroids, and spongy changes. Both treatments showed comparable efficacy in cyst damage and inflammation. The presence of spongy change correlated with spheroids counts and were not affected by anthelmintic treatment. Compared to white matter, gray matter showed greater spongy change (91.7% vs. 21.4%, p < 0.0001), higher spheroids count (45.2 vs. 0.2, p = 0.0001), and increased inflammation (72.0% vs. 21.4%, p = 0.003). In this rat model, anthelmintic treatment destroyed brain parasitic cysts at the cost of local inflammation similar to what is described in human neurocysticercosis. Axonal spheroids and spongy changes as markers of damage were topographically correlated, and not affected by anthelmintic treatment.

HIV and Chagas Disease: An Evaluation of the Use of Real-Time Quantitative Polymerase Chain Reaction to Measure Levels of Trypanosoma cruzi Parasitemia in HIV Patients in Cochabamba, Bolivia.

This cross-sectional study evaluated epidemiologic characteristics of persons living with HIV (PWH) coinfected with Trypanosoma cruzi in Cochabamba, Bolivia, and estimated T. cruzi parasitemia by real-time quantitative polymerase chain reaction (qPCR) in patients with and without evidence of reactivation by direct microscopy. Thirty-two of the 116 HIV patients evaluated had positive serology for T. cruzi indicative of chronic Chagas disease (27.6%). Sixteen of the 32 (50%) patients with positive serology were positive by quantitative polymerase chain reaction (qPCR), and four of the 32 (12.5%) were positive by direct microscopy. The median parasite load by qPCR in those with CD4+ < 200 was 168 parasites/mL (73-9951) compared with 28.5 parasites/mL (15-1,528) in those with CD4+ ≥ 200 (P = 0.89). There was a significant inverse relationship between the degree of parasitemia estimated by qPCR from blood clot and CD4+ count on the logarithmic scale (rsBC= -0.70, P = 0.007). The correlation between T. cruzi estimated by qPCR+ blood clot and HIV viral load was statistically significant with rsBC = 0.61, P = 0.047. Given the significant mortality of PWH and Chagas reactivation and that 57% of our patients with CD4+ counts < 200 cells/mm3 showed evidence of reactivation, we propose that screening for chronic Chagas disease be considered in PWH in regions endemic for Chagas disease and in the immigrant populations in nonendemic regions. Additionally, our study showed that PWH with advancing immunosuppression have higher levels of estimated parasitemia measured by qPCR and suggests a role for active surveillance for Chagas reactivation with consideration of treatment with antitrypanosomal therapy until immune reconstitution can be achieved.

Building Public Health Capacity through a Sustainable South-South-North Training Program.

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. This collaboration has led to a groundswell of research on clinically significant diseases, outreach to more than 800 scientists, several dozen publications, and the start of four institutional review boards. South-South and South-South-North collaborations should publish their experiences, and Northern funding organizations should consider funding such collaborations.

How Should Public Health Schools Help Meet Millennium Development Goals in Latin America?

The Millennium Development Goals (MDGs) are a set of 8 aims adopted by the United Nations to create a more peaceful, prosperous, and just world. Four MDGs directly concern public health, and public health schools should be involved in meeting them. The Johns Hopkins University-directed Fogarty Global Infectious Disease Research Training Program in Peru and Bolivia, funded by the Fogarty International Center of the National Institutes of Health, has spanned nearly 3 decades and provides a case study of how low-resource interventions can help meet MDGs.

Exhaled Nitric Oxide is Not a Biomarker for Pulmonary Tuberculosis.

To reduce transmission of tuberculosis (TB) in resource-limited countries where TB remains a major cause of mortality, novel diagnostic tools are urgently needed. We evaluated the fractional concentration of exhaled nitric oxide (FeNO) as an easily measured, noninvasive potential biomarker for diagnosis and monitoring of treatment response in participants with pulmonary TB including multidrug resistant-TB in Lima, Peru. In a longitudinal study however, we found no differences in baseline median FeNO levels between 38 TB participants and 93 age-matched controls (13 parts per billion [ppb] [interquartile range (IQR) = 8-26] versus 15 ppb [IQR = 12-24]), and there was no change over 60 days of treatment (15 ppb [IQR = 10-19] at day 60). Taking this and previous evidence together, we conclude FeNO is not of value in either the diagnosis of pulmonary TB or as a marker of treatment response.

Correction: Colorimetric Detection of Plasmodium vivax in Urine Using MSP10 Oligonucleotides and Gold Nanoparticles.

[This corrects the article DOI: 10.1371/journal.pntd.0005029.].

Colorimetric Detection of Plasmodium vivax in Urine Using MSP10 Oligonucleotides and Gold Nanoparticles.

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. vivax is understudied and to achieve control of malaria in endemic areas, a rapid, accurate, and simple diagnostic tool is necessary. In this pilot study, we found that a colorimetric system using AuNPs and MSP10 DNA detection in urine can provide fast, easy, and inexpensive identification of P. vivax. The test exhibited promising sensitivity (84%), high specificity (97%), and only mild cross-reactivity with P. falciparum (21%). It is simple to use, with a visible color change that negates the need for a spectrometer, making it suitable for use in austere conditions. Using urine eliminates the need for finger-prick, increasing both the safety profile and patient acceptance of this model.

In Vitro Study of Taenia solium Postoncospheral Form.

BACKGROUND: The transitional period between the oncosphere and the cysticercus of Taenia solium is the postoncospheral (PO) form, which has not yet been completely characterized. The aim of this work was to standardize a method to obtain T. solium PO forms by in vitro cultivation. We studied the morphology of the PO form and compared the expression of antigenic proteins among the PO form, oncosphere, and cysticerci stages. METHODOLOGY/PRINCIPAL FINDINGS: T. solium activated oncospheres were co-cultured with ten cell lines to obtain PO forms, which we studied at three stages of development--days 15, 30, and 60. A high percentage (32%) of PO forms was obtained using HCT-8 cells in comparison to the other cell lines. The morphology was observed by bright field, scanning, and transmission electron microscopy. Morphology of the PO form changed over time, with the six hooks commonly seen in the oncosphere stage disappearing in the PO forms, and vesicles and microtriches observed in the tegument. The PO forms grew as they aged, reaching a diameter of 2.5 mm at 60 days of culture. 15-30 day PO forms developed into mature cysticerci when inoculated into rats. Antigenic proteins expressed in the PO forms are also expressed by the oncosphere and cysticerci stages, with more cysticerci antigenic proteins expressed as the PO forms ages. CONCLUSIONS/SIGNIFICANCE: This is the first report of an in vitro production method of T. solium PO forms. The changes observed in protein expression may be useful in identifying new targets for vaccine development. In vitro culture of PO form will aid in understanding the host-parasite relationship, since the structural changes of the developing PO forms may reflect the parasite's immunoprotective mechanisms. A wider application of this method could significantly reduce the use of animals, and thus the costs and time required for further experimental investigations.

Novel rat model for neurocysticercosis using Taenia solium.

Neurocysticercosis is caused by Taenia solium infecting the central nervous system and is the leading cause of acquired epilepsy and convulsive conditions worldwide. Research into the pathophysiology of the disease and appropriate treatment is hindered by lack of cost-effective and physiologically similar animal models. We generated a novel rat neurocysticercosis model using intracranial infection with activated T. solium oncospheres. Holtzman rats were infected in two separate groups: the first group was inoculated extraparenchymally and the second intraparenchymally, with different doses of activated oncospheres. The groups were evaluated at three different ages. Histologic examination of the tissue surrounding T. solium cysticerci was performed. Results indicate that generally infected rats developed cysticerci in the brain tissue after 4 months, and the cysticerci were observed in the parenchymal, ventricle, or submeningeal brain tissue. The route of infection did not have a statistically significant effect on the proportion of rats that developed cysticerci, and there was no dependence on infection dose. However, rat age was crucial to the success of the infection. Epilepsy was observed in 9% of rats with neurocysticercosis. In histologic examination, a layer of collagen tissue, inflammatory infiltrate cells, perivascular infiltrate, angiogenesis, spongy change, and mass effect were observed in the tissue surrounding the cysts. This study presents a suitable animal model for the study of human neurocysticercosis.

Taenia solium infection in Peru: a collaboration between Peace Corps Volunteers and researchers in a community based study.

BACKGROUND: Neurocysticercosis is a leading cause of seizures and epilepsy in most of the world, and it occurs when Taenia solium larval cysts infect the central nervous system. T. solium tapeworm infection is endemic in much of Peru, but there are scarce data on the prevalence in many rural highland communities where it is likely to be hyper-endemic. Peace Corps Volunteers live and work in these communities; however, to our knowledge, they have not been used to facilitate public health research. MATERIALS AND METHODS: We utilized Peace Corps Volunteers to estimate the prevalence of T. solium tapeworm infection in seven rural communities in northern Peru. A convenience non-random sampling frame was used. Peace Corps Volunteers facilitated the collection of stool samples (N = 2,328), which were analyzed by sedimentation and microscopy. Niclosamide treatment and purgation preceded species identification, which was done by PCR-REA. RESULTS: Taenia sp. egg-positive stool samples were found in three of the seven communities we surveyed. The overall prevalence of Taenia sp. egg positivity was 2.1% (49/2,328) (95% CI = 1.6-2.8%) with prevalence up to 4.3% (42/977) (95% CI = 3.1-5.8%) by community. All 34 of the specimens tested by PCR-REA were T. solium. The overall prevalence of T. solium tapeworm infection was 1.5% (34/2,328) (95% CI = 1.0-2.0%). Prevalence up to 2.9% (28/977) (95% CI = 1.9-4.1%) by community was observed. CONCLUSION/SIGNIFICANCE: This study recorded high T. solium tapeworm prevalence, and identified hyper-endemic rural communities. It demonstrates that synergy between researchers and Peace Corps Volunteers can be an effective means to conducting large-scale, community-based studies in remote areas of Peru.

How we developed a locally focused Global Health Clinical Preceptorship at Weill Cornell Medical College.

BACKGROUND: Global health educational programs within U.S. medical schools have the opportunity to link their "global" focus with local circumstances by examining the challenges underserved communities face in the United States. AIM: Students in Weill Cornell Medical College's Global Health Clinical Preceptorship (GHCP) learn history-taking and physical examination skills while gaining exposure to local health care disparities and building cultural competency. METHODS: First-year medical students in the program are placed in the office of a physician who works with underserved patient populations in New York City. Students receive an orientation session, shadow their preceptors one afternoon per week for seven weeks, complete weekly readings and assignments on topics specific to underserved populations, attend a reflection session, and write a reflection paper. RESULTS: In three years, 36% of first-year students (112 of 311) opted into the elective GHCP program. Students reported gaining a better understanding of the needs of underserved patient populations, being exposed to new languages and issues of cultural competency, and having the opportunity to work with role model clinicians. CONCLUSIONS: The GHCP is a successful example of how global health programs within medical schools can incorporate a domestic learning component into their curricula.