Progress Toward Onchocerciasis Elimination in Brazil.

The single onchocerciasis-endemic focus in the remote Amazon rainforest is shared by Brazil and Venezuela and affects primarily the indigenous Yanomami people. Regional elimination of onchocerciasis is challenged by the magnitude and inaccessibility of this area. In Brazil, 272 onchocerciasis-endemic communities are operationally organized through 21 health centers ("polos bases"). Mass drug administration of ivermectin began in 1995, with 36 effective biannual rounds (≥85% coverage of the eligible population) through 2022. The national on chocerciasis program maintains community-level monitoring to prioritize treatment activities and epidemiological surveys. The Onchocerciasis Elimination Program for the Americas and the WHO onchocerciasis elimination guidelines have helped Brazil move toward its goal of stopping ivermectin treatment by 2025 and verifying transmission elimination by 2030. Additional challenges to the Brazilian onchocerciasis program include cross-border movements and insecurity due to illegal mining and inter-community conflicts. The new government in Brazil offers hope given its commitment to the equity of indigenous people and preservation of the Amazon environment.

A link between circulating immune complexes and acute kidney injury in human visceral leishmaniasis.

Visceral leishmaniasis (VL) is an infectious disease caused by Leishmania infantum. Clinically, VL evolves with systemic impairment, immunosuppression and hyperactivation with hypergammaglobulinemia. Although renal involvement has been recognized, a dearth of understanding about the underlying mechanisms driving acute kidney injury (AKI) in VL remains. We aimed to evaluate the involvement of immunoglobulins (Igs) and immune complexes (CIC) in the occurrence of AKI in VL patients. Fourteen VL patients were evaluated between early treatment and 12 months post-treatment (mpt). Anti-Leishmania Igs, CIC, cystatin C, C3a and C5a were assessed and correlated with AKI markers. Interestingly, high levels of CIC were observed in VL patients up to 6 mpt. Concomitantly, twelve patients met the criteria for AKI, while high levels of cystatin C were observed up to 6 mpt. Plasmatic cystatin C was positively correlated with CIC and Igs. Moreover, C5a was correlated with cystatin C, CIC and Igs. We did not identify any correlation between amphotericin B use and kidney function markers in VL patients, although this association needs to be further explored in subsequent studies. Our data reinforce the presence of an important renal function impairment during VL, suggesting the involvement of Igs, CIC, and C5a in this clinical condition.

Enterobius vermicularis in Brazil: An integrative review.

Enterobius vermicularis, an intestinal helminth, is transmitted through the ingestion of eggs found in food, water, dust, or other fomites, including infected individuals. This review aimed to examine the frequency and distribution of E. vermicularis infections in Brazil between 1991 and 2022. The conducted bibliographic survey revealed that the frequency of E. vermicularis infections in Brazil ranged from 0.1 to 26.1%, depending on factors such as population ethnicity, individual age group, geographic area, time frame, and diagnostic method. However, these findings were based on a limited number of publications, suggesting that the actual prevalence rates of E. vermicularis infection may still be unknown and potentially underestimated.

Giardia lamblia-infected preschoolers present growth delays independent of the assemblage A, B or E.

BACKGROUND: Intestinal parasite Giardia can affect children's physical development mainly stunting even in asymptomatic cases. The protozoa G. lamblia is divided into assemblages A-H. However, it is still unclear whether clinical manifestations and pathogenesis may vary according to the infecting assemblage. OBJECTIVES: To investigate whether G. lamblia assemblages influence differently the physical development of preschoolers from a community of Rio de Janeiro, Brazil. METHODS: Anthropometric parameters were analysed from children attending a daycare centre and stool samples were obtained for the G. lamblia diagnosis. G. lamblia isolates from positive samples were genotyped. Data were analysed in order to verify whether there is a relationship between G. lamblia infection and the physical development of children according to the assemblage. FINDINGS: Herein we demonstrated that although eutrophic, G. lamblia-infected daycare preschoolers from a low-income community presented growth delay compared to non-infected ones. This effect was observed for the three assemblages (A, B or E) found infecting humans. MAIN CONCLUSION: G. lamblia causes growth delays on children independent of infecting assemblage (A, B or E).

Identification of Immunodominant Proteins of the Leishmania (Viannia) naiffi SubProteome as Pan-Specific Vaccine Targets against Leishmaniasis.

Leishmaniasis is a wide-spectrum disease caused by parasites from Leishmania genus. A well-modulated immune response that is established after the long-lasting clinical cure of leishmaniasis can represent a standard requirement for a vaccine. Previous studies demonstrated that Leishmania (Viannia) naiffi causes benign disease and its antigens induce well-modulated immune responses in vitro. In this work we aimed to identify the immunodominant proteins present in the soluble extract of L. naiffi (sLnAg) as candidates for composing a pan-specific anti-leishmaniasis vaccine. After immunoblotting using cured patients of cutaneous leishmaniasis sera and proteomics approaches, we identified a group of antigenic proteins from the sLnAg. In silico analyses allowed us to select mildly similar proteins to the host; in addition, we evaluated the binding potential and degree of promiscuity of the protein epitopes to HLA molecules and to B-cell receptors. We selected 24 immunodominant proteins from a sub-proteome with 328 proteins. Homology analysis allowed the identification of 13 proteins with the most orthologues among seven Leishmania species. This work demonstrated the potential of these proteins as promising vaccine targets capable of inducing humoral and cellular pan-specific immune responses in humans, which may in the future contribute to the control of leishmaniasis.

Recombinant protein KR95 as an alternative for serological diagnosis of human visceral leishmaniasis in the Americas.

In the Americas, visceral leishmaniasis (VL) is caused by the protozoan Leishmania infantum, leading to death if not promptly diagnosed and treated. In Brazil, the disease reaches all regions, and in 2020, 1,933 VL cases were reported with 9.5% lethality. Thus, an accurate diagnosis is essential to provide the appropriate treatment. Serological VL diagnosis is based mainly on immunochromatographic tests, but their performance may vary by location, and evaluation of diagnostic alternatives is necessary. In this study, we aimed to evaluate the performance of ELISA with the scantily studied recombinant antigens, K18 and KR95, comparing their performance with the already known rK28 and rK39. Sera from parasitologically confirmed symptomatic VL patients (n = 90) and healthy endemic controls (n = 90) were submitted to ELISA with rK18 and rKR95. Sensitivity (95% CI) was, respectively, 83.3% (74.2-89.7) and 95.6% (88.8-98.6), and specificity (95% CI) was 93.3% (85.9-97.2) and 97.8% (91.8-99.9). For validation of ELISA with the recombinant antigens, we included samples from 122 VL patients and 83 healthy controls collected in three regions in Brazil (Northeast, Southeast, and Midwest). When comparing the results obtained with the VL patients' samples, significantly lower sensitivity was obtained by rK18-ELISA (88.5%, 95% CI: 81.5-93.2) compared with rK28-ELISA (95.9%, 95% CI: 90.5-98.5), but the sensitivity was similar comparing rKR95-ELISA (95.1%, 95% CI: 89.5-98.0), rK28-ELISA (95.9%, 95% CI: 90.5-98.5), and rK39-ELISA (94.3%, 95% CI: 88.4-97.4). Analyzing the specificity, it was lowest with rK18-ELISA (62.7%, 95% CI: 51.9-72.3) with 83 healthy control samples. Conversely, higher and similar specificity was obtained by rKR95-ELISA (96.4%, 95% CI: 89.5-99.2), rK28-ELISA (95.2%, 95% CI: 87.9-98.5), and rK39-ELISA (95.2%, 95% CI: 87.9-98.5). There was no difference in sensitivity and specificity across localities. Cross-reactivity assessment, performed with sera of patients diagnosed with inflammatory disorders and other infectious diseases, was 34.2% with rK18-ELISA and 3.1% with rKR95-ELISA. Based on these data, we suggest using recombinant antigen KR95 in serological assays for VL diagnosis.

DC-SIGN receptor is expressed by cells from cutaneous leishmaniasis lesions and differentially binds to Leishmania (Viannia) braziliensis and L. (Leishmania) amazonensis promastigotes.

BACKGROUND: Dendritic cells (DCs) specific intercellular adhesion molecule (ICAM)-3-grabbing non integrin receptor (DC-SIGN) binds to subgenera Leishmania promastigotes mediating its interaction with DC and neutrophils, potentially influencing the infection outcome. OBJECTIVES: In this work, we investigated whether DC-SIGN receptor is expressed in cells from cutaneous leishmaniasis (CL) lesions as well as the in vitro binding pattern of Leishmania (Viannia) braziliensis (Lb) and L. (L.) amazonensis (La) promastigotes. METHODS: DC-SIGN receptor was labeled by immunohistochemistry in cryopreserved CL tissue fragments. In vitro binding assay with CFSE-labeled Lb or La promastigotes and RAJI-transfecting cells expressing DC-SIGN (DC-SIGNPOS) or mock-transfected (DC-SIGNNEG) were monitored by flow cytometry at 2 h, 24 h and 48 h in co-culture. RESULTS: In CL lesion infiltrate, DC-SIGNPOS cells were present in the dermis and near the epidermis. Both Lb and La bind to DC-SIGNPOS cells, while binding to DC-SIGNNEG was low. La showed precocious and higher affinity to DC-SIGNhi population than to DC-SIGNlow, while Lb binding was similar in these populations. CONCLUSION: Our results demonstrate that DC-SIGN receptor is present in L. braziliensis CL lesions and interact with Lb promastigotes. Moreover, the differences in the binding pattern to Lb and La suggest DC-SIGN can influence in a difference way the intake of the parasites at the first hours after Leishmania infection. These results raise the hypothesis that DC-SIGN receptor could participate in the immunopathogenesis of American tegumentary leishmaniasis accounting for the differences in the outcome of the Leishmania spp. infection.

Low doses of 3-phenyl-lawsone or meglumine antimoniate delivery by tattooing route are successful in reducing parasite load in cutaneous lesions of Leishmania (Viannia) braziliensis-infected hamsters.

Current therapeutic ways adopted for the treatment of leishmaniasis are toxic and expensive including parasite resistance is a growing problem. Given this scenario, it is urgent to explore treatment alternatives for leishmaniasis. The aim of this study was to evaluate the effect of 3-phenyl-lawsone (3-PL) naphthoquinone on Leishmania (Viannia) braziliensis infection, both in vitro and in vivo, using two local routes of administration: subcutaneous (higher dose) and tattoo (lower dose). In vitro 3-PL showed low toxicity for macrophages (CC50 >3200 µM/48h) and activity against intracellular amastigotes (IC50 = 193 ± 19 µM/48h) and promastigotes (IC50 = 116 ± 26 µM/72h), in which induced increased ROS generation. Additionally, 3-PL up-regulated the production of cytokines such as tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1), interleukin-6 (IL-6) and IL-10 in infected macrophages. However, the anti-amastigote action was independent of nitric oxide production. Treatment of hamsters infected with L. (V.) braziliensis from one week after infection with 3-PL by subcutaneous (25 µg/Kg) or tattooing (2.5 µg/Kg) route, during 3 weeks (3 times/week) or 2 weeks (2 times/week) significantly decreased the parasite load (p<0.001) in the lesion. The reduction of parasite load by 3-PL treatment was comparable to reference drug meglumine antimoniate administered by the same routes (subcutaneous 1mg/Kg and tattoo 0.1mg/Kg). In addition, treatment started from five weeks after infection with 3-PL per tattoo also decreased the parasite load. These results show the anti-leishmanial effect of 3-PL against L. (V.) braziliensis and its efficacy by subcutaneous (higher dose) and tattoo (lower dose) routes. In addition, this study shows that drug delivery by tattooing the lesion allows the use of lower doses than the conventional subcutaneous route, which may support the development of a new therapeutic strategy that can be adopted for leishmaniasis.

Enterobius vermicularis in Brazil: An integrative review

ABSTRACT Enterobius vermicularis, an intestinal helminth, is transmitted through the ingestion of eggs found in food, water, dust, or other fomites, including infected individuals. This review aimed to examine the frequency and distribution of E. vermicularis infections in Brazil between 1991 and 2022. The conducted bibliographic survey revealed that the frequency of E. vermicularis infections in Brazil ranged from 0.1 to 26.1%, depending on factors such as population ethnicity, individual age group, geographic area, time frame, and diagnostic method. However, these findings were based on a limited number of publications, suggesting that the actual prevalence rates of E. vermicularis infection may still be unknown and potentially underestimated.

Giardia lamblia-infected preschoolers present growth delays independent of the assemblage A, B or E

BACKGROUND Intestinal parasite Giardia can affect children's physical development mainly stunting even in asymptomatic cases. The protozoa G. lamblia is divided into assemblages A-H. However, it is still unclear whether clinical manifestations and pathogenesis may vary according to the infecting assemblage. OBJECTIVES To investigate whether G. lamblia assemblages influence differently the physical development of preschoolers from a community of Rio de Janeiro, Brazil. METHODS Anthropometric parameters were analysed from children attending a daycare centre and stool samples were obtained for the G. lamblia diagnosis. G. lamblia isolates from positive samples were genotyped. Data were analysed in order to verify whether there is a relationship between G. lamblia infection and the physical development of children according to the assemblage. FINDINGS Herein we demonstrated that although eutrophic, G. lamblia-infected daycare preschoolers from a low-income community presented growth delay compared to non-infected ones. This effect was observed for the three assemblages (A, B or E) found infecting humans. MAIN CONCLUSION G. lamblia causes growth delays on children independent of infecting assemblage (A, B or E).

DC-SIGN receptor is expressed by cells from cutaneous leishmaniasis lesions and differentially binds to Leishmania (Viannia) braziliensis and L. (Leishmania) amazonensis promastigotes

BACKGROUND Dendritic cells (DCs) specific intercellular adhesion molecule (ICAM)-3-grabbing non integrin receptor (DC-SIGN) binds to subgenera Leishmania promastigotes mediating its interaction with DC and neutrophils, potentially influencing the infection outcome. OBJECTIVES In this work, we investigated whether DC-SIGN receptor is expressed in cells from cutaneous leishmaniasis (CL) lesions as well as the in vitro binding pattern of Leishmania (Viannia) braziliensis (Lb) and L. (L.) amazonensis (La) promastigotes. METHODS DC-SIGN receptor was labeled by immunohistochemistry in cryopreserved CL tissue fragments. In vitro binding assay with CFSE-labeled Lb or La promastigotes and RAJI-transfecting cells expressing DC-SIGN (DC-SIGNPOS) or mock-transfected (DC-SIGNNEG) were monitored by flow cytometry at 2 h, 24 h and 48 h in co-culture. RESULTS In CL lesion infiltrate, DC-SIGNPOS cells were present in the dermis and near the epidermis. Both Lb and La bind to DC-SIGNPOS cells, while binding to DC-SIGNNEG was low. La showed precocious and higher affinity to DC-SIGNhi population than to DC-SIGNlow, while Lb binding was similar in these populations. CONCLUSION Our results demonstrate that DC-SIGN receptor is present in L. braziliensis CL lesions and interact with Lb promastigotes. Moreover, the differences in the binding pattern to Lb and La suggest DC-SIGN can influence in a difference way the intake of the parasites at the first hours after Leishmania infection. These results raise the hypothesis that DC-SIGN receptor could participate in the immunopathogenesis of American tegumentary leishmaniasis accounting for the differences in the outcome of the Leishmania spp. infection.

Different inoculum of Leishmania braziliensis concentrations influence immunopathogenesis and clinical evolution in the ear dermis hamster model of cutaneous leishmaniasis.

The golden hamster (Mesocricetus auratus) is commonly used as a promising model for Leishmania braziliensis infection developing skin-ulcerated lesions. However, different protocols using high concentration of parasites inoculated in the footpad result in severe clinical disease. Here, we further investigate the outcome of the site of infection and concentration of L. braziliensis parasites inoculated on the immunopathogenesis and clinical evolution. Initially, hamsters were infected in the ear dermis or hind footpad with a concentration of 1 × 105 parasites. Animals infected in the ear dermis developed a disease, with an increased parasite load that more closely resembled human cutaneous leishmaniasis lesions comparing to the group infected in the footpad. Next, we evaluated if different parasite concentrations (104 , 105 and 106 ) inoculated in the ear dermis would impact the course and clinical aspects of infection. Hamsters infected with 104 and 105 parasites developed mild lesions compared to the group infected with 106 that presented severe and persistent lesions. The parasite load varied between the different parasite concentrations. The inflammatory response was more intense when infection was initiated with 106 parasites accompanied by an increased initial expression of IL-4, IL-10 and arginase in the lymph node followed by expression of both pro-and anti-inflammatory cytokines comparing to groups infected with 104 and 105 parasites. In conclusion, the number of parasites inoculated, and the initial site of infection could influence the inflammatory response, and clinical presentation. Our results suggest that the ear dermis infection model induces a chronic disease that relates to immunopathological aspects of CL natural infection.

High Frequency of Cryptosporidium hominis Infecting Infants Points to A Potential Anthroponotic Transmission in Maputo, Mozambique

Cryptosporidium is one of the most important causes of diarrhea in children less than 2 years of age. In this study, we report the frequency, risk factors and species of Cryptosporidium detected by molecular diagnostic methods in children admitted to two public hospitals in Maputo City, Mozambique. We studied 319 patients under the age of five years who were admitted due to diarrhea between April 2015 and February 2016. Single stool samples were examined for the presence of Cryptosporidium spp. oocysts, microscopically by using a Modified Ziehl-Neelsen (mZN) staining method and by using Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP) technique using 18S ribosomal RNA gene as a target. Overall, 57.7% (184/319) were males, the median age (Interquartile range, IQR) was 11.0 (7-15) months. Cryptosporidium spp. oocysts were detected in 11.0% (35/319) by microscopy and in 35.4% (68/192) using PCR-RFLP. The most affected age group were children older than two years, [adjusted odds ratio (aOR): 5.861; 95% confidence interval (CI): 1.532-22.417; p-value < 0.05]. Children with illiterate caregivers had higher risk of infection (aOR: 1.688; 95% CI: 1.001-2.845; p-value < 0.05). An anthroponotic species C. hominis was found in 93.0% (27/29) of samples. Our findings demonstrated that cryptosporidiosis in children with diarrhea might be caused by anthroponomic transmission.

Biomarkers of disease severity in patients with visceral leishmaniasis co-infected with HIV.

Visceral leishmaniasis (VL) is caused by the protozoan Leishmania spp, transmitted by sand fly bites. VL is one of the deadliest tropical infection diseases, yet the coinfection with HIV virus drastically increases relapses, treatment failure and mortality. The concomitant action of these two pathogens leads to high cellular activation independently of the progression to AIDS. In addition, microbial translocation and bacterial infections are thought to contribute worsening the clinical picture. Identifying biomarkers associated with disease severity is of interest for clinical management of patients with VL-HIV/AIDS. Thus, we analyzed in the sera several markers including interleukins (IL-1ß, IL-6, IL-8, and IL-17), interferon-γ (IFN- γ), tumor necrosis factor (TNF), lipopolysaccharide (LPS), soluble CD14 (sCD14), macrophage migration inhibitory factor (MIF) and intestinal fatty acid-binding protein (IFABP). These markers were compared with disease severity in 24 patients with VL/HIV presenting different clinical outcomes. Disease severity was defined by the probability of death calculated using a score set system derived by the Kala-Cal® software. Probability of death ranged from 3.7% to 97.9%, with median of 28.8%. Five patients died (20%). At the univariate analysis, disease severity was correlated with TNF, IFN-γ and sCD14. LPS was positively correlated with sCD14 specifically in patients with low CD4+ count (CD4+ T-cell <200 cells/mL). Most importantly, the multivariate analysis including LPS, CD4+count and sCD14 showed that sCD14 was the only independent predictor for disease severity and death. Altogether, our results indicated that sCD14 is a powerful marker of pathogenicity and death for patients with VL-HIV/AIDS.

Corrigendum to "Nitazoxanide superiority to placebo to treat moderate COVID-19 - A Pilot prove of concept randomized double-blind clinical trial." [EClinicalMedicine 37 (2021) 100981].

[This corrects the article DOI: 10.1016/j.eclinm.2021.100981.].

Increased levels of cortisol are associated with the severity of experimental visceral leishmaniasis in a Leishmania (L.) infantum-hamster model.

BACKGROUND: Several infectious diseases are associated with hypothalamic-pituitary-adrenal (HPA) axis disorders by elevating circulating glucocorticoids (GCs), which are known to have an immunosuppressive potential. We conducted this study in golden hamsters, a suitable model for human visceral leishmaniasis (VL), to investigate the relationship of Leishmania (L.) infantum infection on cortisol production and VL severity. METHODS: L. infantum-infected (n = 42) and uninfected hamsters (n = 30) were followed-up at 30, 120, and 180 days post-infection (dpi). Plasma cortisol was analyzed by radioimmunoassay and cytokines, inducible nitric oxide synthase (iNOS), and arginase by RT-qPCR. RESULTS: All hamsters showed splenomegaly at 180 dpi. Increased parasite burden was associated with higher arginase expression and lower iNOS induction. Cortisol levels were elevated in infected animals in all-time points evaluated. Except for monocytes, all other leucocytes showed a strong negative correlation with cortisol, while transaminases were positively correlated. Immunological markers as interleukin (IL)-6, IL-1ß, IL-10, and transforming growth-factor-ß (TGF-ß) were positively correlated to cortisol production, while interferon-γ (IFN-γ) presented a negative correlation. A network analysis showed cortisol as an important knot linking clinical status and immunological parameters. CONCLUSIONS: These results suggest that L. infantum increases the systemic levels of cortisol, which showed to be associated with hematological, biochemical, and immunological parameters associated to VL severity.

Nitazoxanide superiority to placebo to treat moderate COVID-19 - A Pilot prove of concept randomized double-blind clinical trial.

BACKGROUND: The absence of specific antivirals to treat COVID-19 leads to the repositioning of candidates' drugs. Nitazoxanide (NTZ) has a broad antiviral effect. METHODS: This was a randomized, double-blind pilot clinical trial comparing NTZ 600 mg BID versus Placebo for seven days among 50 individuals (25 each arm) with SARS-COV-2 RT-PCR+ (PCR) that were hospitalized with mild respiratory insufficiency from May 20th, 2020, to September 21st, 2020 (ClinicalTrials.gov NCT04348409). Clinical and virologic endpoints and inflammatory biomarkers were evaluated. A five-point scale for disease severity (SSD) was used. FINDINGS: Two patients died in the NTZ arm compared to 6 in the placebo arm (p = 0.564). NTZ was superior to placebo when considering SSD (p < 0001), the mean time for hospital discharge (6.6 vs. 14 days, p = 0.021), and negative PCR at day 21 (p = 0.035), whereas the placebo group presented more adverse events (p = 0.04). Among adverse events likely related to the study drug, 14 were detected in the NTZ group and 22 in placebo (p = 0.24). Among the 30 adverse events unlikely related, 21 occurred in the placebo group (p = 0.04). A decrease from baseline was higher in the NTZ group for d-Dimer (p = 0.001), US-RCP (p < 0.002), TNF (p < 0.038), IL-6 (p < 0.001), IL-8 (p = 0.014), HLA DR. on CD4+ T lymphocytes (p < 0.05), CD38 in CD4+ and CD8+ T (both p < 0.05), and CD38 and HLA-DR. on CD4+ (p < 0.01). INTERPRETATION: Compared to placebo in clinical and virologic outcomes and improvement of inflammatory outcomes, the superiority of NTZ warrants further investigation of this drug for moderate COVID-19 in larger clinical trials. A higher incidence of adverse events in the placebo arm might be attributed to COVID-19 related symptoms.