Why are tapeworm carriers so difficult to find? A methodological proposal for their search and recovery.

Neurocysticercosis, caused by the larval stage of Taenia solium, is a life-threatening condition and the most severe form of the disease. Yet, despite being a required link in the parasite life cycle, tapeworm carriers are rarely reported. This study is aimed to find and evaluate T. solium carriers, describing some characteristics of these patients and the treatment. Taeniasis cases were searched for in various Mexican states from 1983 to 2016. Previous informed consent, tapeworm-carrier patients were administered with niclosamide and a saline purge. Parasite specimens were recovered and identified, both morphologically and by PCR. From 117 treated patients, Taenia sp. specimens were obtained from 46 subjects (47.8%). From these, complete parasites were recovered from 42 (90.5%), and only detached proglottids from 4 patients. Cases were more frequent in Morelos, Chiapas, and Guerrero. More than one adult cestode was recovered from 4 patients (9.5%). To improve treatment efficacy and adherence, the drug was administered in late afternoon, resulting a high recovery yield of complete parasites (90.5%). The success rate of deworming campaigns in areas of Mexico and the world that are endemic for Taenia sp. could be improved by administering the treatment at times that do not interfere with the patients' daily activities, and national health authorities could apply this simple strategy to help eradication efforts in endemic areas. The detection of carriers will only be possible through the coordinated efforts of public and private health services, a better education of the general population to improve self-detection, and adequate, personalized diagnostic procedures for suspect cases.

Association between cycle threshold (Ct ) values and clinical and laboratory data in inpatients with COVID-19 and asymptomatic health workers.

In-house assays for the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), are feasible alternatives, particularly in developing countries. Cycle threshold (Ct ) values obtained by qRT-PCR were compared with clinical and laboratory data from saliva of inpatients with COVID-19 and asymptomatic health workers (AHW) were studied. Saliva specimens from 58 inpatients confirmed by qRT-PCR for SARS-CoV-2 using nasopharyngeal specimens, and 105 AHW were studied by qRT-PCR using three sets of primers for the N (N1, N2, and N3) gene of SARS-CoV-2, according to the CDC Diagnostic Panel protocol, showing a positivity of 88% for inpatients and 8% for AHW. Bivariate analysis revealed an association between Ct < 38.0 values for N2 and mechanical ventilation assistance among patients (p = .013). In addition, values of aspartate-transaminase, lactate dehydrogenase, and ferritin showed significant correlations with Ct values of N1 and N3 genes in inpatients. Therefore, our results show that Ct values correlate with some relevant clinical data for inpatients with COVID-19.

Measuring student satisfaction as the first assessment of the Program of Combined Studies in Medicine, an MD/PhD-like program of the Faculty of Medicine, National Autonomous University of Mexico.

BACKGROUND: The Program of Combined Studies in Medicine (PECEM, by its acronym in Spanish) is a program for simultaneous bachelor and doctorate studies (MD/PhD) that enrolls students who show academic excellence and interest in scientific research. The initial doctoral training comprises seven six-month research stays in different laboratories or clinical or computer areas with different high-quality scientific advisors who provide students with a unique experience for their scientific training. Therefore, satisfaction in this stage is decisive for students' performance and physical and psychological health. The aim of the present study was to administer a questionnaire to measure students' satisfaction with their research experience as a service-product bundle. METHODS: Students answered an online questionnaire that evaluated three dimensions: perceived quality of the advisor, skills development, and infrastructure and support. Several satisfiers were also evaluated: recommendation of the advisor to peers, fulfillment of student expectations and satisfaction with the program. Correlations were calculated using Fisher's exact test. The significance was set at p < 0.05. RESULTS: The high quality of the advisor, skills development and guidance during the stay were satisfiers correlated to the students' recommendation of their advisors to their peers and to the fulfillment of the students' scientific expectations. Conversely, skills development and infrastructure and support were satisfiers for a good to excellent experience as a PECEM student. A lack of direct interaction with the advisor's workgroup was related to dissatisfaction. CONCLUSIONS: The nontangible products of the service, such as a positive interaction between the student, the advisor and the advisor's workgroup as well as support obtained during the research stay, were satisfiers. These data indicate that promoting a fruitful bond between the student and advisor is a priority to ensure the quality of our innovative MD/PhD program.

Calreticulin in phagocytosis and cancer: opposite roles in immune response outcomes.

Calreticulin (CRT) is a pleiotropic and highly conserved molecule that is mainly localized in the endoplasmic reticulum. Recently, CRT has gained special interest for its functions outside the endoplasmic reticulum where it has immunomodulatory properties. CRT translocation to the cell membrane serves as an "eat me" signal and promotes efferocytosis of apoptotic cells and cancer cell removal with completely opposite outcomes. Efferocytosis results in a silenced immune response and homeostasis, while removal of dying cancer cells brought about by anthracycline treatment, ionizing-irradiation or photodynamic therapy results in immunogenic cell death with activation of the innate and adaptive immune responses. In addition, CRT impacts phagocyte activation and cytokine production. The effects of CRT on cytokine production depend on its conformation, species specificity, degree of oligomerization and/or glycosylation, as well as its cellular localization and the molecular partners involved. The controversial roles of CRT in cancer progression and the possible role of the CALR gene mutations in myeloproliferative neoplasms are also addressed. The release of CRT and its influence on the different cells involved during efferocytosis and immunogenic cell death points to additional roles of CRT besides merely acting as an "eat me" signal during apoptosis. Understanding the contribution of CRT in physiological and pathological processes could give us some insight into the potential of CRT as a therapeutic target.

A population genetics analysis in clinical isolates of Sporothrix schenckii based on calmodulin and calcium/calmodulin-dependent kinase partial gene sequences.

Sporotrichosis is a subcutaneous mycosis that is caused by diverse species of Sporothrix. High levels of genetic diversity in Sporothrix isolates have been reported, but few population genetics analyses have been documented. To analyse the genetic variability and population genetics relations of Sporothrix schenckii Mexican clinical isolates and to compare them with other reported isolates. We studied the partial sequences of calmodulin and calcium/calmodulin-dependent kinase genes in 24 isolates; 22 from Mexico, one from Colombia, and one ATCC® 6331™; the latter was used as a positive control. In total, 24 isolates were analysed. Phylogenetic, haplotype and population genetic analyses were performed with 24 sequences obtained by us and 345 sequences obtained from GenBank. The frequency of S. schenckii sensu stricto was 81% in the 22 Mexican isolates, while the remaining 19% were Sporothrix globosa. Mexican S. schenckii sensu stricto had high genetic diversity and was related to isolates from South America. In contrast, S. globosa showed one haplotype related to isolates from Asia, Brazil, Spain and the USA. In S. schenckii sensu stricto, S. brasiliensis and S. globosa, haplotype polymorphism (θ) values were higher than the nucleotide diversity data (π). In addition, Tajima's D plus Fu and Li's tests analyses displayed negative values, suggesting directional selection and arguing against the model of neutral evolution in these populations. In addition, analyses showed that calcium/calmodulin-dependent kinase was a suitable genetic marker to discriminate between common Sporothrix species.

The amniotic band syndrome in the rat is associated with the activation of transforming growth factor-ß.

Amniocentesis in rats is associated with different malformations, such as cleft palate and limb deformation, resembling the human congenital amniotic band syndrome (ABS). Despite many human cases reported in the literature, little is known about the mechanisms involved in ABS. This study addressed if the activation of the transforming growth factor-ß1 (TGF-ß1) pathway is, in part, associated with amniotic band formation and growth restriction induced in rats by amniocentesis, as by a previously published model. For this purpose, quantification of TGF-ß1, α-smooth muscle actin, and collagen type I mRNA and protein levels were determined by quantitative PCR and Western blot analysis, respectively, in the fetus, its amniotic membrane, and the uterus of experimental and control rats. We found that TGF-ß1 mRNA levels are increased in the fetus and the amniotic membrane at 6 hours, whereas α-smooth muscle actin, phosphorylated Smad3, and collagen type I increased at 48 hours, suggesting that a fibrotic response is induced after the amniotic sac puncture. Furthermore, fetuses had hemorrhages, syndactyly, and amputation of limbs, similar to human ABS.

Update of phylogenetic and genetic diversity of Sporothrix schenckii sensu lato.

Sporothrix schenckii sensu lato causes subcutaneous mycosis. In this article we analysed its phylogeny and genetic diversity using calmodulin DNA sequences deposited in GenBank database. Population genetics indices were calculated, plus phylogenetic and haplotype network trees were built. Five clades with high values of posterior probability, 47 haplotypes and high diversity in the complex were found. Analysis of partial calmodulin sequences alignment revealed conserved and polymorphic regions that could be used as reference for taxonomic identification. The use of population genetics analysis allowed understanding the phylogenetic proximity of S. schenckii s. str. and S. brasiliensis; scarce genetic flow among them with low migration index and high ancestry coefficient was found. Similarly, S. globosa, S. mexicana and S. pallida sequences showed highly differentiated species with no genetic exchange. The phylogenetic tree suggests that S. mexicana shared a common ancestor with S. pallida; while S. globosa and S. brasiliensis are more related to S. schenckii s. str. and showed less haplotype diversity and restrictions in geographic distribution. In the haplotype network tree S. schenckii s. str. species displayed worldwide distribution without dispersion centres; while S. brasiliensis and S. globosa, exhibited Brazil and Euro-Asia as dispersion centres, respectively. Our data suggest that S. schenckii complex has been submitted to a divergent evolution process, probably due to the pressure of the environment and of the host. In contrast, S. brasiliensis could have been submitted to purifying selection or expansion process.

Cost of neurocysticercosis patients treated in two referral hospitals in Mexico City, Mexico.

OBJECTIVES: To estimate annual costs related to the diagnosis, treatment and productivity losses among patients with neurocysticercosis (NCC) receiving treatment at two referral hospitals, the Instituto Nacional de Neurologia y Neurocirugia (INNN) and the Hospital de Especialidades of the Instituto Mexicano del Seguro Social (HE-IMSS), in Mexico City from July 2007 to August 2008. METHODS: Information on presenting clinical manifestations, diagnostic tests, hospitalisations, surgical procedures and other treatments received by NCC outpatients was collected from medical charts, and supplemented by an individual questionnaire regarding productivity losses and out-of-pocket expenses related to NCC. RESULTS: The annual average per-patient direct costs were US$ 503 (95% CI: 414-592) and US$ 438 (95% CI: 322-571) for patients without a history of hospitalisation and/or surgery seen at the INNN and the HE-IMSS, respectively. These costs increased to US$ 2506 (95% CI: 1797-3215) and US$ 2170 (95% CI: 1303-3037), respectively, for patients with a history of hospitalisation and/or surgery. The average annual per-patient indirect costs were US$ 246 (95% CI: 165-324) and US$ 114 (95% CI: 51-178), respectively, using minimum salary wages for individuals not officially employed. CONCLUSIONS: The total annual cost for patients who had and had not been hospitalised and/or undergone a surgical procedure for the diagnosis or treatment of NCC corresponded to 212% and 41% of an annual minimum wage salary, respectively. The disease tends to affect rural socioeconomically disadvantaged populations and creates health disparities and significant economic losses in Mexico.

An Overview on Research in a University Hospital, Using a Payback Framework Categorization Approach.

BACKGROUND AND OBJECTIVE: Little information is available on how to assess the impact of research studies conducted in government hospitals in Latin America and specifically in Mexico. We aimed to determine the returns on investment of the research projects that were carried out in the Hospital General "Dr. Manuel Gea Gonzalez" (HGMGG), a general university hospital located in Mexico City, using a categorization model. METHODS: We conducted a study including bibliometric analyses of publications associated with all research studies performed during the period 2016-2019 in the HGMGG and investigator interviews, according to the payback framework categorization model. RESULTS: All studies analyzed had a positive impact based on outcomes in 5 "payback categories": (1) knowledge; (2) research targeting, capacity building, and absorption; (3) policy and product development; (4) health benefits; and (5) broader economic benefits. CONCLUSIONS: To date, it has not been possible to establish a set of indicators that show the results of the investigations carried out by medical specialists in training, who carry out the bulk of medical care in general hospitals and in the National Institutes of Health in Mexico. We identified, in the 5 categories of the payback framework model, different areas of opportunity to improve the benefits of the hospital's medical services through the development of scientific research projects.

Fc-gamma receptor expression and cytokine responses to intravenous human immunoglobulin in whole blood from non-pregnant and pregnant women and newborns.

BACKGROUND: Intravenous immunoglobulin (IVIG) can suppress the inflammatory response in adults, but its role in pregnant women and newborns is poorly studied. While the adult immune system is considered mature, it is immature in neonates and suppressed in pregnancy. Since the immune response differs in these 3 groups, the use of IVIG could differentially modulate the immune response. OBJECTIVES: We aimed to explore the effect of IVIG on myeloid blood cells from non-pregnant women, pregnant women and newborns. MATERIAL AND METHODS: Whole blood from healthy donors was incubated with lipopolysaccharide (LPS) and/or IVIG. After 0 h, 24 h and 48 h of culture, Fc-gamma receptor (CD16, CD32 and CD64) expression, monocyte and neutrophil bacterial phagocytosis, and cytokine and chemokine concentrations were determined in the supernatant. RESULTS: The baseline expression of monocyte CD16 was higher in newborns than in adult women, but the expression of CD32 and CD64 was similar between groups. Furthermore, LPS and IVIG stimulation, together or separately, did not change Fc-gamma receptor expression in monocytes or neutrophils and did not modify their phagocytosis capacity. On the other hand, IVIG did not downregulate the proinflammatory cytokine response induced by LPS in any group. Interestingly, IVIG induced a strong interleukin 8 (IL-8) response in neonates but not in non-pregnant or pregnant women. CONCLUSIONS: Our results show that IVIG did not induce changes in Fc-gamma receptor expression, phagocytic ability, or the cytokine response to LPS in blood cells from neonates, non-pregnant or pregnant women. However, IVIG induced a strong IL-8 response in neonates that could improve immunity.

State of the art of Taenia solium as compared to Taenia asiatica.

Three species of tapeworms infect humans in their adult stage (Taenia solium, Taenia saginata and Taenia asiatica). The 3 are flat, opaque white or yellowish, and exceptional long segmented parasites, measuring 1 to 12 m in their adult stage. In this review, the development of the knowledge regarding the first species, mainly focused on understanding how the larval stage or cysticercus is transmitted to humans, is described. The second species is a cosmopolitan parasite that only causes taeniosis and not cysticercosis; therefore, it will not be included. Information on the third species, which is presently being produced, since this species was recognized as such only at the end of the 20th century, will be discussed at the end of this review.

[Flu symptoms and preventive measures practiced by the inhabitants of Mexico City during the AH1N1 influenza epidemic]. / Sintomas de influenza y medidas preventivas que practicaron los habitantes de la Ciudad de Mexico durante la epidemia de influenza AH1N1.

OBJECTIVE: To know the frequency of flu symptoms and describe preventive measures practiced by the inhabitants of Mexico City during the AH1N1 epidemic. MATERIAL AND METHODS: A cross-sectional design was used and a survey containing demographic and health information was conducted in August and September 2009 in a sample of 4003 randomly selected people living in Mexico City. RESULTS: Referred flu symptoms were: 29% running nose, 25% cough, 25% throat infection, 17% muscle and joint pain, 10% respiratory problems, and 7% fever. Also 16% said having hypertension, 10% diabetes, and 2% morbid obesity. Among the preventive measures, 74% washed hands, 32% covered the nose and mouth with the forearm when coughing or sneezing, 28% used sanitizer gel five times a day in average, and 47% did not greet with a kiss or handshake. CONCLUSIONS: Almost all the population followed preventive measures and did not show high percentages of influenza symptoms. Useful elements for prevention were identified, such as the frequency of seasonal influenza vaccination, self-medication, and living with a person diagnosed with AH1N1. It is important to continue with mass communication to strengthen adequate hygiene and health measures.

The many faces of parasite calreticulin.

Calreticulin from parasites and its vertebrate hosts share ~50% identity and many of its functions are equally conserved. However, the existing amino acid differences can affect its biological performance. Calreticulin plays an important role in Ca2+ homeostasis and as a chaperone involved in the correct folding of proteins within the endoplasmic reticulum. Outside the endoplasmic reticulum, calreticulin is involved in several immunological functions such as complement inhibition, enhancement of efferocytosis, and immune upregulation or inhibition. Several parasite calreticulins have been shown to limit immune responses and promote infectivity, while others are strong immunogens and have been used for the development of potential vaccines that limit parasite growth. Furthermore, calreticulin is essential in the dialogue between parasites and hosts, inducing Th1, Th2 or regulatory responses in a species-specific manner. In addition, calreticulin participates as initiator of endoplasmic reticulum stress in tumor cells and promotion of immunogenic cell death and removal by macrophages. Direct anti-tumoral activity has also been reported. The highly immunogenic and pleiotropic nature of parasite calreticulins, either as positive or negative regulators of the immune response, render these proteins as valuable tools to modulate immunopathologies and autoimmune disorders, as well as a potential treatment of neoplasms. Moreover, the disparities in the amino acid composition of parasite calreticulins might provide subtle variations in the mechanisms of action that could provide advantages as therapeutic tools. Here, we review the immunological roles of parasite calreticulins and discuss possible beneficial applications.

Elevated Levels of Cytotoxicity, Cytokines, and Anti-SARS-CoV-2 Antibodies in Mild Cases of COVID-19.

Current evidence shows higher production of cytokines and antibodies against severe acute respiratory coronavirus 2 (SARS-CoV-2) in severe and critical cases of Coronavirus Disease 2019 (COVID-19) in comparison with patients with moderate or mild disease. A recent hypothesis proposes an important role of genotoxicity and cytotoxicity in the induction of the cytokine storm observed in some patients at later stages of the disease. Interestingly, in this study, we report significantly higher levels of interleukin (IL)-1ß, IL-6, MCP-1, and IL-4 cytokines in mild COVID-19 patients versus severe cases, as well as a high frequency of karyorrhexis (median [Me] = 364 vs. 20 cells) and karyolysis (Me = 266 vs. 52 cells) in the mucosal epithelial cells of both groups of patients compared with uninfected individuals. Although we observed higher levels of anti-SARS-CoV-2 IgM and IgG antibodies in COVID-19 patients, IgM antibodies were significantly higher only in mild cases, for the N and the S viral antigens. High levels of IgG antibodies were observed in both mild and severe cases. Our results showed elevated concentrations of proinflammatory and anti-inflammatory cytokines in mild cases, which may reflect an active innate immune response and could be related to the higher IgM and IgG antibody levels found in those patients. In addition, we found that SARS-CoV-2 infection induces cytotoxic damage in the oral mucosa, highlighting the importance of studying the genotoxic and cytotoxic events induced by infection and its role in the pathophysiology of COVID-19.

Are basophils important mediators for helminth-induced Th2 immune responses? A debate.

Helminth parasites induce Th2 immune responses. Immunological mechanisms leading to Th2 induction are mainly dependent on IL-4. However, early source of IL-4 has not been precisely identified. Noticeably, basophils seem to be important mediators for inducing and maintaining the Th2 response probably because they secrete IL-4 and exert functions similar to APCs. Nevertheless, recent experimental evidence points that DCs could be also significant participants during this process. The involvement of basophils during memory responses is also discussed.

Immunological mechanisms involved in the protection against intestinal taeniosis elicited by oral immunization with Taenia solium calreticulin.

Oral immunization with functional recombinant Taenia solium calreticulin (rTsCRT) induces 37% reduction in tapeworm burden in the experimental model of intestinal taeniosis in hamsters. Furthermore, tapeworms recovered from vaccinated animals exhibit diminished length, being frequently found in more posterior parts of the small intestine. The aim of this study was to analyze the immunological mechanisms involved in protection in response to rTsCRT oral immunization. Hamsters were orally immunized with rTsCRT using cholera toxin (CT) as adjuvant, weekly for 4 weeks. Fifteen days after the last boost animals were challenged with four T. solium cysticerci. Reduction in the adult worm recovery and increased transcription of mRNA for IL-4 and IFN-γ in the mucosa of rTsCRT+CT immunized animals were observed. Immunization also induced goblet cell hyperplasia in the mucosa surrounding the implantation site of the parasite. Specific IgG and IgA antibodies in serum and fecal supernatants were detected after the second immunization, being more pronounced after challenge. Our data suggest that oral vaccination with rTsCRT+CT regulates a local expression of IL-4 and IFN-γ, stimulating secretion of IgA that, together with the increase of goblet cells and mucin production, could result in an unfavorable environment for T. solium promoting an impaired tapeworm development.

Findings related to IL-8 and IL-10 gene polymorphisms in a Mexican patient population with irritable bowel syndrome infected with Blastocystis.

The intestinal protozoan parasite Blastocystis is one of the most common parasites worldwide in humans and, although its ability to cause human disease has been questioned, some reports have demonstrated that this microorganism is associated to the development of irritable bowel syndrome (IBS) and to a proinflammatory response, in which the expression of some cytokines is unregulated. Since inflammatory cytokine gene polymorphisms might have a role in the pathophysiology of IBS, we assessed the role of single nucleotide polymorphisms (SNPs) for interleukin (IL)-8 and IL-10, in previously collected DNA samples from IBS patients and controls, with or without Blastocystis infection. IL-8+396(G) and IL-10-1082 (A) alleles (p=0.0437 and p=0.0267, respectively), as well as their homozygous (p<0.0001 and p=0.0039, respectively) and IL-8+781(CT) (p=0.0248) genotypes were significantly overrepresented in patients with IBS in comparison with controls. IL-8+396(GG) genotype was relevant because it was associated to IBS (p<0.0001), to Blastocystis (p=0.0025), and to IBS­Blastocystis (p=0.0272). In the latter binomial association, this genotype presented a high contribution (etiological fraction =0.452) and a risk >fourfold to develop IBS. IL-8+781 (T) and IL-10-592 (C) alleles were also associated to Blastocystis and to IBS­Blastocystis, respectively (p=0.0448 and p=0.0166). Our results suggest that some IL-8 and IL-10 SNPs could change individual susceptibility increasing the relative risk in the development of IBS in Blastocystis carriers.

Blastocystis infection is associated with irritable bowel syndrome in a Mexican patient population.

In recent times, some common "non-pathogenic" parasites, such as Blastocystis and Dientamoeba fragilis, have been associated to the aetiology of irritable bowel syndrome (IBS), while host pro-inflammatory cytokine gene polymorphisms might have a role in the pathophysiology of the disease. Therefore, Blastocystis subtypes (ST), D. fragilis and gene promoter single nucleotide polymorphisms of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in IBS patients and controls were studied. After giving written consent, 45 patients with symptoms of IBS according to the Rome III criteria and 45 controls were enrolled. DNA was extracted from peripheral blood for SNP analysis at position -174 for IL-6 as well as -238 and -308 for TNF-α. Blastocystis was more common in the IBS group (p = 0.043). Interestingly, D. fragilis was found more frequently in the control group (p = 0.002); Blastocystis ST1 and 3 were most frequent in both groups. Haploview analysis revealed linkage disequilibrium in TNF-α (p < 0.0001); however, none of the SNPs for IL-6 and TNF-α were found to be significantly related with IBS. The clinical and molecular approaches undertaken for the first time in Latin American IBS patients demonstrated an association with Blastocystis that supports a pathogenic role of this parasite in IBS Furthermore, co-infections with ST1 and ST3 were frequent; thus, the genetic diversity proposed within ST polymorphisms does not rule out that particular strains might be associated with disease. In addition, our results do not support a major contribution of IL-6 and TNF-α gene polymorphisms in the susceptibility to IBS.

Identification of α-L-fucosidase (ALFuc) of Blastocystis sp. subtypes ST1, ST2 and ST3.

Blastocystis sp. is a common intestinal microorganism. The α-L-fucosidase (ALFuc) is an enzyme long associated with the colonization of the gut microbiota. However, this enzyme has not been experimentally identified in Blastocystis cultures. The objective of the present study was to identify ALFuc in supernatants of axenic cultures of Blastocystis subtype (ST)1 ATCC-50177 and ATCC-50610 and to compare predicted ALFuc proteins of alfuc genes in sequenced STs1-3 isolates in human Blastocystis carriers. Excretion/secretion (Es/p) and cell lysate proteins were obtained by processing Blastocystis ATCC cultures and submitting them to SDS-PAGE and immunoblotting. In addition, 18 fecal samples from symptomatic Blastocystis human carriers were analyzed by sequencing of amplification products for subtyping. A complete identification of the alfuc gene and phylogenetic analysis were performed. Immunoblotting showed that the amplified band corresponding to ALFuc (~51 kDa) was recognized only in the ES/p. Furthermore, prediction analysis of ALFuc 3D structures revealed that the domain α-L-fucosidase and the GH29 family's catalytic sites were conserved; interestingly, the galactose-binding domain was recognized only in ST1 and ST2. The phylogenetic inferences of ALFuc showed that STs1-3 were clearly identifiable and grouped into specific clusters. Our results show, for the first time through experimental data that ALFuc is a secretion product of Blastocystis sp., which could have a relevant role during intestinal colonization; however, further studies are required to clarify this condition. Furthermore, the alfuc gene is a promising candidate for a phylogenetic marker, as it shows a conserved classification with the SSU-rDNA gene.

Neurocysticercosis in Latin America: Current epidemiological situation based on official statistics from four countries.

BACKGROUND: Neurocysticercosis (NC) is one of the major parasitic diseases affecting the central nervous system and is endemic in much of Asia, sub-Saharan Africa, and Latin America. Its epidemiology is difficult to assess, although official registries are available in Brazil, Colombia, Ecuador, and Mexico. METHODOLOGY/PRINCIPAL FINDINGS: Using official statistics, we assessed trends in NC hospitalization rates during 1998-2019 in Brazil and Ecuador, during 2004-2019 in Mexico, and during 2009-2019 in Colombia. We also assessed the trend in NC mortality in Brazil (1998-2019), the trend in hospitalizations for NC in a Mexican tertiary-level hospital (Instituto Nacional de Neurología y Neurocirugía [INNN]; 1995-2019), and in Mexican primary care ambulatory clinics (1995-2019). Associations between NC hospitalization rates and the human development index (HDI) were also examined. In Brazil, Ecuador, and Mexico, statistically significant decreases in NC hospitalization rates were observed. In Mexico, a significant increase in the age of patients at INNN was observed, suggesting a decreasing incidence of recent infection. Conversely, a significant increase in NC hospitalization rate was observed in Colombia. HDI was not significantly associated with NC hospitalization rates when adjusting for time. CONCLUSIONS: The downward trends in NC cases in Brazil, Ecuador, and Mexico are encouraging, especially in the context of the PAHO/WHO plan of action to eliminate neglected tropical diseases from the region. On the other hand, in Colombia, the increased NC hospitalization rate is concerning and needs further evaluation so that the authorities can take specific measures. These results should encourage health authorities in other endemic countries to establish a system of official registries to identify where the need for a control program is most urgent. However, it is also important to remember that NC persists, although less frequently in some Latin American countries, and efforts to achieve its control must continue.