Schistosoma mansoni infection and related knowledge among schoolchildren in an endemic area of Minas Gerais, Brazil, prior to educational actions.

As a signatory to World Health Assembly Resolution WHA65.21 on eliminating schistosomiasis, the Brazilian Ministry of Health (MoH) recommends early identification and timely treatment of the infection carriers for morbidity control, plus complementary preventive measures, such as health education, for transmission control. This study reports infection and awareness of schistosomiasis among schoolchildren before the implementation of school-based educational actions in an endemic municipality with persisting moderate prevalence levels despite successive control campaigns since the late 1990s. A questionnaire was applied in April 2013 to schoolchildren in the middle years of schooling (6th to 8th year) of Malacacheta municipality to assess baseline knowledge and risk behaviour related to schistosomiasis. A stool survey was conducted in May/June 2013 in 2519 schoolchildren from all years of fundamental education (first to 9th year) to identify the infection carriers, as well as to assess baseline prevalence and intensity of infection using the Kato-Katz method (one sample, two slides). The infected schoolchildren were treated promptly with single-dose praziquantel 60mg/kg and followed up after 45days for treatment efficacy. Relevant outcomes from baseline stool survey, treatment and follow-up were statistically evaluated in relation to area of residence (rural/urban), gender, age group (<11/≥years) and infection. Adherence to baseline survey was 81.2%, and prevalence of infection was 21.4%. Of the 539 positives, 60 (11.1%) had ≥400 eggs per gram of faeces (heavy-intensity infection). Prevalence of infection was significantly higher among rural residents and≥11year olds, whereas intensity of infection was higher among rural residents,≥11year olds and boys. Adherence by the positives to treatment was 93.3% and adherence by the treated children to 45-day follow-up was 72.2%. At 45days after treatment, 97.0% of the 363 children surveyed were egg-negative; the egg reduction rate was 99.4%. Of the 924 children who responded to the questionnaire, 95.5% showed awareness of schistosomiasis, although 76.2% reported contact with natural, unsafe bodies of water. Reported contact with water was significantly more frequent among infected than non-infected, and boys than girls. The results show persisting infection and risk behaviour among schoolchildren, regardless of their basic knowledge about schistosomiasis. These are grounds for implementing specific educational actions to improve awareness and behavioural change, jointly with other control measures, to attain the MoH goals.

Disinfection of domestic effluents by gamma radiation: effects on the inactivation of Ascaris lumbricoides eggs.

This work investigated the inactivation of Ascaris lumbricoides eggs in domestic effluents by gamma radiation from a (60)Co source. Domestic wastewater was treated in a compact demo-scale system consisting of a UASB reactor and a trickling filter; treatment was carried out at the Center for Research and Training on Sanitation (CePTS), Federal University of Minas Gerais, in Belo Horizonte-MG, Brazil. One-liter of treated wastewater samples was artificially contaminated with an average of 1000 non-embryonated Ascaris lumbricoides eggs from human feces; samples were then irradiated in a multiple-purpose irradiator at different doses (0.5-5 kGy). Eggs were recovered from the wastewater and the viability of these irradiated eggs was evaluated; the description of the egg developmental phases with each dose of gamma radiation was recorded. Radiation doses of 3.5 kGy effectively disinfected effluents with lower concentrations of A. lumbricoides eggs; higher radiation doses of 5 kGy were necessary to disinfect effluents with higher eggs concentrations.

The Estrada Real project and endemic diseases: the case of schistosomiasis, geoprocessing and tourism.

Geographical Information System (GIS) is a tool that has recently been applied to better understand spatial disease distributions. Using meteorological, social, sanitation, mollusc distribution data and remote sensing variables, this study aimed to further develop the GIS technology by creating a model for the spatial distribution of schistosomiasis and to apply this model to an area with rural tourism in the Brazilian state of Minas Gerais (MG). The Estrada Real, covering about 1,400 km, is the largest and most important Brazilian tourism project, involving 163 cities in MG with different schistosomiasis prevalence rates. The model with three variables showed a R(2) = 0.34, with a standard deviation of risk estimated adequate for public health needs. The main variables selected for modelling were summer vegetation, summer minimal temperature and winter minimal temperature. The results confirmed the importance of Remote Sensing data and the valuable contribution of GIS in identifying priority areas for intervention in tourism regions which are endemic to schistosomiasis.

The Estrada Real project and endemic diseases: the case of schistosomiasis, geoprocessing and tourism

Geographical Information System (GIS) is a tool that has recently been applied to better understand spatial disease distributions. Using meteorological, social, sanitation, mollusc distribution data and remote sensing variables, this study aimed to further develop the GIS technology by creating a model for the spatial distribution of schistosomiasis and to apply this model to an area with rural tourism in the Brazilian state of Minas Gerais (MG). The Estrada Real, covering about 1,400 km, is the largest and most important Brazilian tourism project, involving 163 cities in MG with different schistosomiasis prevalence rates. The model with three variables showed a R² = 0.34, with a standard deviation of risk estimated adequate for public health needs. The main variables selected for modelling were summer vegetation, summer minimal temperature and winter minimal temperature. The results confirmed the importance of Remote Sensing data and the valuable contribution of GIS in identifying priority areas for intervention in tourism regions which are endemic to schistosomiasis.

Host immune response to Toxoplasma gondii and Ascaris lumbricoides in a highly endemic area: evidence of parasite co-immunomodulation properties influencing the outcome of both infections.

Toxoplasmosis and ascaridiasis evoke polar Th-1 and Th-2 host immune responses, respectively. A study to investigate the specific cytokine profile production by in vitro cultures of peripheral blood mononuclear cells from individuals living under precarious sanitary conditions in a highly endemic area for the parasites Toxoplasma gondii and Ascaris lumbricoides was conducted. High levels of both IFN-gamma (Th-1) and IL-13 (Th-2) were observed in groups of co-infected individuals presenting toxoplasmic ocular lesions. Significantly lower IL-10 and TGF-beta levels were produced by co-infected individuals in comparison with groups of individuals not infected with A. lumbricoides and either positive or negative for T. gondii living under good sanitary conditions (control groups). The possible influence of co-parasitism on the clinical presentation of ocular toxoplasmosis is discussed.

Host immune response to Toxoplasma gondii and Ascaris lumbricoides in a highly endemic area: evidence of parasite co-immunomodulation properties influencing the outcome of both infections

Toxoplasmosis and ascaridiasis evoke polar Th-1 and Th-2 host immune responses, respectively. A study to investigate the specific cytokine profile production by in vitro cultures of peripheral blood mononuclear cells from individuals living under precarious sanitary conditions in a highly endemic area for the parasites Toxoplasma gondii and Ascaris lumbricoides was conducted. High levels of both IFN-³ (Th-1) and IL-13 (Th-2) were observed in groups of co-infected individuals presenting toxoplasmic ocular lesions. Significantly lower IL-10 and TGF-² levels were produced by co-infected individuals in comparison with groups of individuals not infected with A. lumbricoides and either positive or negative for T. gondii living under good sanitary conditions (control groups). The possible influence of co-parasitism on the clinical presentation of ocular toxoplasmosis is discussed.

Preliminary description of a new entomoparasitic nematode infecting Lutzomyia longipalpis sand fly, the vector of visceral leishmaniasis in the New World.

Phlebotomine sandflies are vectors of important pathogens world-wide, including Leishmania spp. in the Neotropics. Entomoparasites have been described from phlebotomines, including virus, bacteria, protozoa, fungi, nematodes, and mites, some of which are capable of killing the host. In the present study, interference, fluorescence, and scanning electron microscopies were used for the first time to detect and morphologically characterize a new entomoparasite infecting Lutzomyia longipalpis. Several filiform larvae and eggs in different stages were encountered in the abdomen of female and male insects. Pairs of large egg-bearing nematodes found within cyst-like structures or free in the hemocel accompanied by larvae could be the adult sexual stages. This entomoparasite infects sand flies naturally in the field. We believe that stress caused by the colonization procedure produced an increase in the infection rate among sand flies affecting their development. These findings could be applied to future biological control studies of sand fly vectors.

Infection with Schistosoma mansoni correlates with altered immune responses to Ascaris lumbricoides and hookworm.

Studies were performed on humoral and cellular immune responses of patients from areas in Brazil endemic for hookworm and Ascaris lumbricoides, and either endemic or non-endemic for Schistosoma mansoni. Humoral and cellular responses were evaluated by enzyme-linked immunosorbant assay (ELISA) and peripheral blood mononuclear cell (PBMC) proliferation assays against larval hookworm antigens, A. lumbricoides egg antigens, and soluble egg antigens (SEA) or soluble whole adult antigenic preparation (SWAP) from S. mansoni. Patients from S. mansoni-endemic areas, who currently had only hookworm or Ascaris infections, expressed lower humoral and cellular responses to hookworm or Ascaris antigens, respectively, than did their counterparts from areas not endemic for S. mansoni. Individuals from S. mansoni endemic area, although without detectable S. mansoni infection, do mount humoral and cellular responses to SEA and SWAP. This group of individuals has been probably in contact with S. mansoni antigens, since the groups harboring A. lumbricoides or hookworm infections from non-S. mansoni endemic areas do not have detectable anti-S. mansoni responses. PBMC proliferative responses discriminated well between patients with active hookworm infections versus ascariasis, if they were from areas not endemic for S. mansoni.

Cellular responses and cytokine profiles in Ascaris lumbricoides and Trichuris trichiura infected patients.

The impact of intestinal helminth infection, i.e. Ascaris lumbricoides and Trichuris trichiura, on cellular responsiveness and cytokine production was investigated in young adults. Ascaris-specific cellular responsiveness was higher in parasite-free endemic controls than in patients infected with T. trichiura, or A. lumbricoides, or patients co-infected with both parasites. Also, mitogen-induced tumour necrosis factor (TNF)-alpha, interleukin (IL)-12 and interferon (IFN)-gamma secretion by peripheral blood mononuclear cells (PBMC) was higher in negative endemic controls than in infected individuals. Ascaris antigen-specific production of TNF-alpha, IL-12 and IFN-gamma was low in singly Ascaris as well as in co-infected patients, whereas secretion of IL-10 and IL-13 was elevated and similarly high in all patient groups. The detection of Trichuris-specific and Ascaris-specific IgG4 revealed significantly higher serum antibody levels in Trichuris or Ascaris patients when compared to endemic controls (P < 0.05), whereas parasite-specific IgE antibody levels were similarly high in infected individuals and in endemic controls. In summary, chronically infected Ascaris and Trichuris patients with a high parasite load presented reduced cellular reactivity and lower type 1 TNF-alpha, IFN-gamma and IL-12 responses when compared with endemic controls, whereas type 2 IL-10 and IL-13 productions were similar in all groups from the endemic area. The former may support parasite persistence, whereas substantial type 2 cytokine release may promote protective immunity, suggesting an adaptation of the host to control the parasite burden while minimizing immune-mediated host self-damage.

Re-evaluation of schistosomiasis mansoni in Minas Gerais, Brazil, III: "noroeste de Minas" mesoregion

Com o objetivo de verificar a possivel presenca da esquistossomose mansoni na mesorregiao Noroeste de Minas, area do estado de Minas Gerais ate o momento considerada indene para aquela parasitose, foi realizado um levantamento malacologico e um diagnostico coproscopico nos 13 municipios da mesorregiao. Foram coletados e examinados 3.627 planorbideos, identificados como Biomphalaria straminea em sete municipios (Unai, Bonfinopolis de Minas, Paracatu, Joao Pinheiro, Vazante, Lagamar e Lagoa Grande) e B. peregrina em um (Presidente Olegario). Os moluscos estavam negativos para S. mansoni. O exame coproscopico, pelo metodo Kato-Katz, foi realizado em 3.283 estudantes do primeiro grau da rede estadual de ensino. Quatro estudantes foram diagnosticados com esquistossomose nos municipios de Buritis, Formoso, Paracatu e Unai. Entretanto, nenhum dos casos foi considerado autoctone. Podemos concluir que a mesorregiao do Noroeste de Minas continua livre da esquistossomose, mas a presenca de hospedeiros intermediarios enfatiza a necessidade de implantacao de um programa de vigilancia epidemiologica na mesorregiao Noroeste de Minas...

Immunological profiles of patients from endemic areas infected with Schistosoma mansoni

Crude extracts of eggs (SEA) adult worms (SWAP) or cercariae (Cerc) have been used to stimulate Peripheral Blood Mononuclear cells (PBMC) and have provided rather distinct profiles of responses in different types of patients. In genenral it is clear that patients with early infections respond strongly to SEA while response to SWAP are developed more slowly. As infection progresses into the more chronic phases, a general pattern is seen whic leads to lower anti-SEA proliferative responses in the face of higher responses to SWAP and variable anti-cerc responsiveness. Cured not re-exposed patients express very high levels of anti-SEA proliferation. It has recently been seen that those individuals who live in endemic areas and have continued water contact, but are reapeatedly stool-negative (who are presumed to have self-cured or be putatively resistant; endemic normals) are strongly responsive to antigenic extracts, particularly to SEA. Furthermore, our results show that endemic normal individuals have significantly higher IFN gamma production upon PBMC stimulation with schistosome antigens than infected individuals. With the emergence of more studies it is becoming apparent that both the intensity and the prevalence of a given area may influence or shape the general responsiveness of the population under study