Could diet composition modulate pathological outcomes in schistosomiasis mansoni? A systematic review of in vivo preclinical evidence.

Schistosomiasis and malnutrition are often overlapped in poor communities, resulting in disproportionately high mortality rates. Currently, fragmented data make it difficult to define the relationship between diet and schistosomiasis. Thus, we systematically review the preclinical evidence on the impact of diet in Schistosoma mansoni infection. From a structured search, we recovered 27 original articles. All studies used mice and most of them investigated hypoproteic (70.37%), hyperlipidic (22.22%) or vitamin-deficient (7.41%) diets. Diets based on carbohydrate, zinc or milk supplementation were investigated at a reduced frequency (3.70% each). Hypoproteic diets attenuated parasitic load and granulomatous inflammation, but also reduced host resistance to S. mansoni infection, determining higher mortality rates. By stimulating steatohepatitis, parasitic load and granulomatous inflammation, hyperlipidic diets increase organ damage and mortality in infected animals. Although a high-sugar diet and vitamin restriction potentiate and zinc supplementation attenuates S. mansoni infection, the current evidence for these diets remains inconclusive. Analysis of methodological quality indicated that the current evidence is at high risk of bias due to incomplete characterization of the experimental design, diet composition and treatment protocols. From the bias analysis, we report methodological limitations that should be considered to avoid systematic reproduction of inconsistent and poorly reproducible experimental designs.

Could age and aging change the host response to systemic parasitic infections? A systematic review of preclinical evidence.

The impact of age and aging in the evolution of systemic parasitic infections remains poorly understood. We conducted a systematic review from preclinical models of Chagas disease, leishmaniasis, malaria, sleeping sickness and toxoplasmosis. From a structured and comprehensive search in electronic databases, 29 studies were recovered and included in the review. Beyond the characteristics of the experimental models, parasitological and immunological outcomes, we also discussed the quality of current evidence. Our findings indicated that throughout aging, parasitemia and mortality were consistently reduced in Chagas disease and malaria, but were similar or increased in leishmaniasis and highly variable in toxoplasmosis. While a marked humoral response in older animals was related to the anti-T. cruzi protective phenotype, cellular responses mediated by a polarized Th1 phenotype were associated with a more effective defense against Plasmodium infection. Conversely, in leishmaniasis, severe infections and high mortality rates were potentially related to attenuation of humoral response and an imbalance between Th1 and Th2 phenotypes. Due to the heterogeneous parasitological outcomes and limited immunological data, the role of aging on toxoplasmosis evolution remains unclear. From a detailed description of the methodological bias, more controlled researches could avoid the systematic reproduction of inconsistent and poorly reproducible experimental designs.

Challenges of immunosuppressive and antitrypanosomal drug therapy after heart transplantation in patients with chronic Chagas disease: A systematic review of clinical recommendations.

BACKGROUND: Although contraindicated for decades, heart transplantation (HT) has finally become a feasible therapeutic option for the treatment of Chagasic patients with end-stage heart failure. Part of the success in achieving acceptable survival rates after HT is due to the enhancement of the pharmacological management of allograft rejection and reactivation of Trypanosoma cruzi infection. METHODS: By using the framework of a systematic review, we investigated if Chagasic patients who have undergone a HT are treated with similar immunosuppressive and antitrypanosomal regimens in endemic and non-endemic countries and exhibits similar T. cruzi reactivation, allograft rejection and survival rates. From a structured search in PubMed/Medline, Scopus, and Web of Sciences databases, 30 clinical studies were reviewed. RESULTS AND CONCLUSION: Although immunosuppressive regimens are variable in endemic and non-endemic countries, the current evidence supports the administration of lower doses of corticosteroids, adjusted cyclosporine levels (100-150 ng/mL) 3 months after HT, and azathioprine rather than mycophenolate mofetil to reduce the risk of T. cruzi reactivation and rejection episodes. Antitrypanosomal therapy exclusively based on benznidazole, nifurtimox, and allopurinol was consistent in endemic and non-endemic countries, achieving effective results in the control of infection reactivation. The evidence that supports prophylactic antitrypanosomal therapy or administration of allopurinol alone is limited. By highlighting the main sources of research bias, we hope that our critical analysis can help to expedite clinical research and to reduce methodological bias, thereby improving the quality of evidence in new research initiatives.

Prevalence and risk factors for intestinal parasitic infections in children attending daycare centers in Alfenas, southern Minas Gerais, Brazil

Intestinal parasitic infections are common among pre-school children in developing countries and they are often associated with gastrointestinal morbidity such as chronic diarrhea and malnutrition. Their circulation is mainly associated with lack of personal hygiene and environmental sanitation, as well as limited housing and food conditions. As the diagnosis of intestinal parasites is not a simple procedure, especially in population studies, due to difficulties encountered in strategies to obtain fecal samples, reliable prevalence data are scarce. Indeed, the epidemiological data on the prevalence of these parasites in different locations are important for the development of appropriate control measures. This study aimed to investigate the prevalence and risk factors associated with intestinal parasitic infection in children attending three public municipal daycare centers in Alfenas, MG. Three fecal samples from each child were collected on alternate days and processed by the spontaneous sedimentation technique and also through the commercially available centrifugal concentration technique, known as the TF-Test® (TFT). Information on the biological, social and physical environment, in which the children lived, were obtained through the application of a socio-epidemiological questionnaire to the parents or guardians and daycare staff. Giardia duodenalis was the parasite species most frequently detected among the children, with a positive rate of 27.8% (77/277). Entamoeba coli was detected in one of the daycare centers studied, with positivity rate of 43.7%, (7/16); and helminth infection in only two children. The present study showed that children of municipal daycare centers in Alfenas could be at risk of infection by intestinal parasites.