Schistosoma mansoni infection decreases IL-33-mRNA expression and increases CXCL9 and CXCL10 production by peripheral blood cells.

Schistosoma mansoni infections, particularly egg antigens, induce Th2-dominant granulomatous responses accompanied by remarkable immunoregulatory mechanisms that avoid intense fibrosis. Interleukin (IL)-33 is a cytokine that stimulates the early activation of Th2 responses, and its soluble ST2 receptor (sST2) avoids granulomatous response, as well as CXCL9 and CXCL10 chemokines that have antifibrotic activity. However, in schistosomiasis, these molecules have not been suitably studied. Therefore, this study aimed to measure IL-33 and sST2 RNA, cytokines, and chemokines in peripheral blood cultures from individuals living in schistosomiasis-endemic areas. Peripheral blood cells from individuals with S. mansoni (n = 34) and non-infected individuals (n = 31) were cultured under mitogen stimulation. Supernatant chemokines and cytokines were evaluated using a cytometric bead array, and IL-33 and sST2 mRNA expression was measured using qPCR. Infected individuals showed higher levels of CXCL8, CXCL9, CXCL10, IFN-γ, TNF-α, IL-6, IL-2, IL-4, and IL-10; there was a lower expression of IL-33 mRNA and similar expression of sST2mRNA in infected than non-infected individuals. In conclusion, for the first time, we demonstrated lower IL-33mRNA expression and high levels of the antifibrotic chemokines CXCL9 and CXCL10 in schistosomiasis mansoni, which could control exacerbations of the disease in individuals from endemic areas.

Schistosoma mansoni infection is associated with decreased risk of respiratory allergy symptoms and low production of CCL2.

OBJECTIVES: We measured the production of cytokines, chemokines and antibodies involved in allergic responses and sCD23 levels during Schistosoma mansoni infection. METHODS: Individuals (n = 164) were selected using the ISAAC questionnaire and parasitological exams. The subjects were divided as follows: those infected individuals with allergy-related symptoms (A-I), those with allergy-related symptoms only (A-NI); those only infected (NA-I); and those non-infected individuals without allergy-related symptoms (NA-NI). We used supernatants from cell culture (mitogenic stimulation) to measure cytokine and chemokine levels using cytometric bead arrays. Serum levels of anti-Ascaris lumbricoides (Asc) and anti-Blomia tropicalis IgE were measured using ImmunoCAP, and sCD23 was measured using ELISA. RESULTS: Schistosoma mansoni infection was associated with a lower risk of allergy-related symptoms. In A-I, there were higher levels of TNF-α, IL-10, IL-6, IFN-γ and CXCL8 than in NA-NI group, with TNF-α and IL-6 also at higher levels compared to A-NI group. Levels of IL-6, CXCL8, total and anti-Asc IgE, as well as the numbers of eosinophils, were higher in NA-I than in NA-NI, and the antibodies were also lower in A-NI than in NA-I group. In AI and NA-I, there was less production of CCL2 than in NA-NI. There were no differences in the levels of IL-2, IL-4, IL-17, CCL5, sCD23 and anti-Blomia IgE. CONCLUSIONS: Patients with allergy-related symptoms and infected (simultaneously) had higher levels of IL-10; due to the infection, there was increased production of IL-6 and CXCL8 and less CCL2. These data may characterize deviation to Th1 or attenuation of the Th2 response in allergy sufferers in areas endemic for schistosomiasis.

Does physical exercise influence in the development of neuroeschistosomiasis?

Neuroschistosomiasis is a severe form of presentation of schistosomiasis in which Schistosoma spp. affects the central nervous system. This is the first study performed to analyze whether there is any relationship between physical effort and the appearance of neuroschistosomiasis, through clinical, molecular and immunological evaluations. An experimental controlled study using 64 male Balb/c inbred mice divided into four groups according to presence or absence of S. mansoni infection and submitted to physical effort or resting was conducted. Thirteen weeks after exercise training, S. mansoni DNA was detected in the brain or spinal cord in about 30% of the infected animals moreover, only S. mansoni-positive samples showed positive labeling for S. mansoni antigens in the brain or spinal cord, with a striking reaction inside the microglia. However, the behavioral tests did not show any clinical symptoms of neuroschistosomiasis in animals submitted to physical effort or in resting. In animals with S. mansoni-positive DNA, immunohistochemical data revealed astrogliosis and microgliosis, elevated IL-10 levels and decreased TNF-α expression. This study demonstrated that isometric exercise does not promote neuroschistosomiasis, furthermore, ectopic forms of schistosomiasis in the central nervous system were largely asymptomatic and exhibited a Th2 immune response profile. More experimental studies are necessary in order to characterize the pathological process of experimental neuroschistosomiasis.

Mesenteric ischemia as a cause of early death among mice infected by Schistosoma mansoni

Laboratory maintenance of the Schistosoma mansoni cycle is necessary for developing studies regarding the diagnosis, treatment and control of schistosomiasis. Within this perspective, it is paramount that mice infected by the parasite should present a minimum survival of six months. However, between October 2016 and May 2017, early deaths were observed among infected animals kept in the vivarium of the Schistosomiasis Reference Service of IAMFIOCRUZ. Therefore, the purpose of the present study was to present the results obtained after investigating the main cause of death among these animals. To achieve this, animals that died or that needed to be euthanized due to clinical distress caused by parasite infection were necropsied to investigate the cause of death and clinical condition. Fragments from the intestines, mesenteric vessels and livers were removed and were subjected to histopathological studies. In addition, mouse feces were collected and analyzed using the hydrogen peroxide reaction to detect occult blood. Over an eight-month period, 70 deaths were noted. Forty two animals presented mesenteric ischemia, a vascular insufficiency syndrome that causes a reduction in the nutrient supply to the intestinal viscera. There is, therefore, a need to reduce the infective parasite load in mice to increase their survival, reduce distress caused by the infection and ensure maintenance of the S. mansoni cycle, thus enabling continuity of scientific studies on this parasitosis.

Epidemiology and anthropology: an integrated approach dealing with bio-socio-cultural aspects as strategy for the control of endemic diseases

The control of endemic diseases has not attained the desired level of effectiveness in spite of the use of modern efficient technologies. The classic interventionist approach for the control of schistosomiasis is centered on systemic control of the snail hosts combined to large scale medical treatment and is usually carried out without social preocupation due to the assisted communities. It is easy to understand the interest and the ethical compromise of public health research while producing studies in which the biological and social determinants as well as the cultural components should be considered and also encompass the historical dimensions and symbolic representations. In face of the recent political decision in favor of decentralizations of health administration to municipal level, we suggest, in the present paper, an integrated approach for the epidemiological diagnosis of an endemic situation at local level. Theoretical and methodological aspects from both, epidemiology and anthropology are discussed. Epidemiological methods can be used to detect the dependent variables (those related to the human infection) and the independent variables (demographic, economic, sanitary and social). Another methodological approach of anthropological/etnographic nature can be conducted in order to make an articulation of the knowledge on the various dimensions or determinant levels of the disease. Mutual comprehension, between researchers and the people under investigation, on the dynamic transmission process would be relevant for a joint construction, at local level, of programmed actions for the control of endemic diseases. This would extend reflections on the health/disease process as a whole.

Schistosomiais control based on repeated chemotherapy in rural village of sugar-cane zone in northeast Brazil

A schedule of repeated chemotherapy with oxamniquine, consisting of biannual treatment of school-aged (7-13 years) children and annual treatment of all other age groups, was used in a representative rural village from a highly endemic area of schistosomiasis in Pernambuco. Significant reductions in infection were obtained only after two cycles of treatment, as the overall prevalence decreased from 72.6 per cent to 41.7 per cent and the geometric mean egg counts per gram of faeces among positives fell from 188.4 to 76. In a school-aged cohort (n=29) three treatment at six-month intervals were necessary to significantly reduce the proportion of positive (from 75.9 per cent to 51.7 per cent). In a cohort of children under 7 years of age (n=20) the proportion of positives actually increased (from 30 per cent to 45 per cent) despite two annual treatments. Water contact was intense and host snails density was relatively high. As there is no short-term perspective of improved sanitation, auxiliary measures such as focal mollusciciding are needed for an adequate control of schistosomiasis in this and alike areas.

Esquistossomose em Pernambuco: determinantes bio-ecológicos e sócio-culturais em comunidade de pequenos agricultores da Zona da Mata

Os programas de controle das endemias, no Brasil, não têm conseguido eficiência nas suas ações, nem mesmo estando instrumentalizados com tecnologias eficazes. A lógica clássica, intervencionista e medicalizada das ações programáticas está centrada no ataque sistemático ao caramujo vetor e ao parasito, num total descompromisso social para com as comunidades assistidas. Compreende-se assim, o interesse e o compromisso ético da pesquisa em saúde pública em proceder a estudos onde os eventos ligados ao processo saúde/doença das comunidades fossem abordados com uma concepção estrutural de causas, integrando investigação e participação social. Dentro desta perspectiva articulada, merecem destaque como atributos causais não só os determinantes biológicos, mas também os sociais e ainda o componente cultural na sua dimensão histórica e representações simbólicas. A área de estudo escolhida foi a comunidade agrícola de Natuba, situada a cerca de 100 Km do Recife, localidade endêmica para esquistossomose e com estrutura político/comunitária organizada. Os recursos do método epidemiológico foram empregados para detectar as variáveis dependentes (relacionadas com a infecção humana) e independentes (demográficas, econômicas, sanitárias e sociais) através de questionário aplicado a todas as residências. Uma segunda abordagem metodológica, de cunho antropológico etnográfico, foi instrumentalizada através de entrevistas abertas e observação participante. O que se pretendeu, no final do estudo, foi fazer a articulação do conhecimento da doença esquistossomática nas suas várias dimensões ou níveis determinantes. Esta compreensão mútua, por parte dos pesquisadores e dos pesquisados, sobre os processos que intervêm na dinâmica de transmissão, permitiu a identificação de elementos relevantes para a construção conjunta de ações programáticas de controle dessa endemia, a nível local, com reflexos bem mais abrangentes para a saúde como um todo.

Esquistossomose em Pernambuco: determinantes bio-ecológicos e sócio-culturais em comunidade de pequenos agricultores da Zona da Mata / Schistosomiasis in Pernambuco State: the biological,, social and cultural determinants in the small agricultural workers community in Zona da Mata, PE, Brazil

Os programas de controle das endemias, no Brasil, não têm conseguido eficiência nas suas ações, nem mesmo estando instrumentalizados com tecnologias eficazes. A lógica clássica, intervencionista e medicalizada das ações programáticas está centrada no ataque sistemático ao caramujo vetor e ao parasito, num total descompromisso social para com as comunidades assistidas. Compreende-se assim, o interesse e o compromisso ético da pesquisa em saúde pública em proceder a estudos onde os eventos ligados ao processo saúde/doença das comunidades fossem abordados com uma concepção estrutural de causas, integrando investigação e participação social. Dentro desta perspectiva articulada, merecem destaque como atributos causais não só os determinantes biológicos, mas também os sociais e ainda o componente cultural na sua dimensão histórica e representações simbólicas. A área de estudo escolhida foi a comunidade agrícola de Natuba, situada a cerca de 100 Km do Recife, localidade endêmica para esquistossomose e com estrutura político/comunitária organizada. Os recursos do método epidemiológico foram empregados para detectar as variáveis dependentes (relacionadas com a infecção humana) e independentes (demográficas, econômicas, sanitárias e sociais) através de questionário aplicado a todas as residências. Uma segunda abordagem metodológica, de cunho antropológico etnográfico, foi instrumentalizada através de entrevistas abertas e observação participante. O que se pretendeu, no final do estudo, foi fazer a articulação do conhecimento da doença esquistossomática nas suas várias dimensões ou níveis determinantes. Esta compreensão mútua, por parte dos pesquisadores e dos pesquisados, sobre os processos que intervêm na dinâmica de transmissão, permitiu a identificação de elementos relevantes para a construção conjunta de ações programáticas de controle dessa endemia, a nível local, com reflexos bem mais abrangentes para a saúde como um todo.