Morphological effects on helminth parasites caused by herbicide under experimental conditions / Efeitos morfológicos em helminto parasito causado por herbicida em condições experimentais

Abstract Helminth parasites have been studied as potential accumulators for different pollutants. Echinostoma paraensei is a foodborne trematode whose vertebrate host, the rodent Nectomys squamipes, is naturally exposed to environmental pesticides. However, little information exists regarding the pesticide's effects on helminths. This study investigated the morphological effects on the trematode, E. paraensei, after experimental Roundup® herbicide exposure, in concentrations below those recommended for agricultural use. After two hours of exposure, scanning electron microscopy (SEM) showed changes to the tegument, such as furrowing, shrinkage, peeling, spines loss on the peristomic collar, and histopathological evidence of altered cells in the cecum and acinus vitelline glands with vacuoles and structural changes to the muscular layers. Glycidic content was decreased, primarily in the connective tissue. As E. paraensei is an intestinal parasite of the semi-aquatic wild rodent, N. squamipes, it is predisposed to pesticide exposure resulting from agricultural practices. Therefore, we emphasize the need to evaluate its impact on helminth parasites, due to their pivotal role in regulating host populations.

Resumo Helmintos parasitos tem sido estudados como acumuladores potenciais para diferentes poluentes. O trematódeo E. paraensei tem como hospedeiro vertebrado o roedor Nectomys squamipes naturalmente exposto a pesticidas no meio ambiente. No entanto, pouca informação está disponível sobre os efeitos dos pesticidas em helmintos parasitos. O presente estudo investigou, em condições experimentais, os efeitos morfológicos no trematódeo E. paraensei após a exposição ao herbicida Roundup®, em concentrações abaixo das recomendadas para a utilização agrícola. A microscopia eletrônica de varredura (MEV) mostrou após duas horas de exposição, alterações no tegumento, como enrugamento, contração e descamação com perda de espinhos no colar peristômico e análise histopatológica evidenciou células do ceco alteradas, as glândulas vitelínicas com vacúolos e mudanças estruturais nas camadas musculares. Diminuição do conteúdo glicídico, principalmente no tecido conjuntivo, também foi observado. Considerando a predisposição à exposição a pesticidas agrícolas de N. squamipes infectado por E. paraensei, são necessários estudos para avaliar o impacto de tais resíduos frente aos helmintos e seus hospedeiros.

Intestinal parasitic infections in a lowincome urban community: prevalence and knowledge, attitudes and practices of inhabitants of Parque Oswaldo Cruz, Rio de Janeiro, Brazil

Intestinal parasitic infections (IPIs) are present in Brazil from upper-to low-income communities, with varying infection estimates; however, they affect those living in urban and rural poverty more severely, without adequate access to consistently safe drinking water, sanitation, waste disposal, medical access and education. Estimates show the need for establishing infection prevalence and socioeconomic features, along with population knowledge, attitudes and practices (KAP) regarding IPIs. The purpose of this study is to assess the prevalence and KAP regarding IPIs of residents of an urban low-income community (Parque Oswaldo Cruz/Amorim) of the Complexo de Manguinhos, Rio de Janeiro, Brazil. The Lutz sedimentation technique was used for parasite detection (n=1,121) and, to obtain data on community KAP regarding IPIs, a KAP survey, adapted from Mello et al. was applied (n=505). An overall prevalence of 20.7% was detected with protozoa composing 92.9% (n=235) of the positive samples. Questionnaires revealed generally correct knowledge but with several inconsistencies, unawareness of the association between the etiological agent and the disease, and uncertainty regarding own knowledge of the subject. The population understood the importance of prevention and was willing to utilize prevention strategies despite being unsure of how to prevent infection. Further studies are required to investigate best practices for improving health equity, community health empowerment and IPIs prevention in Rio de Janeiro, Brazil.

Association between clinical indications and coproparasitological tests carried out at the Pedro Ernesto University Hospital (HUPE/UERJ) in Rio de Janeiro, Brazil

Enteroparasitosis is a public health problem in Brazil. Clinical indications and the appropriate stool examination are essential to obtain an adequate result. This study aims to evaluate whether the clinical indications and the choice of coproparasitological tests requested by the medical services may influence the diagnosis of enteroparasitosis. The data was obtained from the records in the Laboratory of Parasitology at the Pedro Ernesto University Hospital (HUPE/ UERJ) of the State University of Rio de Janeiro (UERJ) from 2009 to 2014. The qualitative variables were grouped in medical services (medical surgery, infectious and parasitic diseases, gastroenterology, pediatrics and rheumatology); types of tests requested (parasitological stool examination (PSE), merthiolate-iodine-formaldehyde (MIF), and sodium-acetate acetic acidformaldehyde (SAF)) and clinical indications (anemia, diarrhea, abdominal pain, eosinophilia, routine tests, HTLV patients, HIV patients, parasitosis and transplantation research). The chi square (X²) and the Spearman coefficient correlation tests were performed to calculate the association between the clinical indications and the coproparasitological tests. A significant association was evident in the clinical indication: parasitosis found among the MIF tests and Trichrome Wheatley (ρ = 0.980). In other clinical indications such as anemia, surgery/ transplant, diarrhea, patients with HIV, HTLV and eosinophilia (despite the PSE tests and MIF having presented a strong link (ρ = 0.802), there was no significant association among the tests. Clinical indications are essential and they have a great influence on the parasitological diagnosis, requiring a combination of diagnostic methods for the detection of protozoa and helminths of medical interest.

Carbohydrate metabolism alterations in Biomphalaria glabrata infected with Schistosoma mansoni and exposed to Euphorbia splendens var. hislopii latex

This paper evaluates the alterations in the glycogen content of tissues (digestive gland and cephalopedal mass) and glucose in the haemolymph of Biomphalaria glabrata BH strain infected with Schistosoma mansoni BH strain and exposed to the latex of Euphorbia splendens var. hislopii. A reduction in the glycogen deposits was observed in infected snails exposed and not exposed to latex. However, the exposure to latex caused a greater depletion of the glycogen levels in both sites analysed, especially from the third week onward. The utilisation of latex as a molluscicide to control the population of infected B. glabrata selectively is proposed.

An improvement of calcium determination technique in the shell of molluscs

The complexometric method is usually applied to quantitative calcium determination in different materials; however the application of this method to calcium determination in molluscs shells infers significant interferences to the results. The snail Bradybaena similaris, a terrestrial gastropod, was used as experimental model to the improvement of this method. The shells were calcinated and dissolved in nitric acid, the hydrogen peroxide was also used to clarify the medium after the acid addition. The calcination procedure and the use of nitric acid reduced the significantly the interferences, allowing a major degree of destruction of the organic substances of the shell. The improvement of the calcium determination technique usually employed showed calcium content of 874.24 ± 56.617 mg of CaCO3/g of ash in comparison to the conventional technique that allowed the determination of 607.79 ± 67.751 mg of CaCO3/g of shell, wet weight.

O método complexométrico é geralmente utilizado para determinação quantitativa de cálcio em diferentes materiais; contudo a aplicação deste método à determinação de cálcio em conchas de moluscos infere significativas interferências aos resultados obtidos. O molusco Bradybaena similaris, um gastrópode terrestre, foi utilizado como modelo para aperfeiçoar este método. As conchas foram calcinadas e dissolvidas em ácido nítrico, o peróxido de hidrogênio também foi empregado para clarificar o meio após a adição do ácido. O processo de calcinação e o uso do ácido nítrico reduziram significativamente as interferências, permitindo um maior grau de destruição das substâncias orgânicas da concha. O aperfeiçoamento da técnica para determinação de cálcio empregado resultou em uma quantidade maior de cálcio igual a 874.24 ± 56.617 mg de CaCO3/g de cinzas em comparação com a técnica convencional que permitiu a determinação de 607.79 ± 67.751 mg de CaCO3/g de concha, peso fresco.

Reproductive activity alterations on the Biomphalaria glabrata exposed to Euphorbia splendens var. hislopii latex

The reproductive activity of Biomphalaria glabrata exposed to Euphorbia splendens var. hislopii latex was evaluated. Parameters related to fecundity and fertility were observed. The snails were exposed to the LD50 (1 mg/l) of crude latex. At the first week post exposure (p.e.), the egg laying was reduced. After the fourth week p.e., an increase of the number of eggs/snail occurred. The results showed a marked reduction in the hatching of the snails, revealing an interference of latex exposure with the reproductive process of B. glabrata of E. splendens var. hislopii. The LD50 of the latex may be used as an alternative method to control the size of the populations of B. glabrata in field.

Lymnaea truncatula Muller, 1774 (Pulmonata: Lymnaeidae) infected with Fasciola hepatica (Linnaeus, 1758) (Trematoda: Digenea), in Moscow districts, Russian Federation

Estudou-se a abundância sazonal e taxas de infecção naturais por Fasciola hepatica em Lymnaea truncatula em áreas rurais endêmicas da região de Moscou. As coletas de campo foram realizadas mensalmente entre maio e outubro de 2002 em duas fazendas de gado do distrito de Naro-Fominsk e duas do distrito de Dmitrov. A abundância de caramujos foi máxima em maio (189 caracóis na primavera) e mínima em julho, (5 caracóis no verão), provavelmente devido às condições apropriadas dos biótopos ao desenvolvimento do molusco durante a primavera. A prevalência dos caramujos infectados durante o período estudado foi de 14,3por cento, sendo mais alta (12,5por cento) e mais baixa (0,53por cento) em setembro e maio, respectivamente.

Parasitas gastrointestinais em cães institucionalizados no Rio de Janeiro, RJ / Intestinal parasitic helminths in institutionalized dogs of Rio de Janeiro, Brazil

Foi estudada a ocorrência de parasitas gastrointestinais em cães recolhidos e mantidos em instituto público de medicina veterinária no Rio de Janeiro, RJ. Amostras de fezes frescas foram coletadas em março de 2004 e analisadas pelos métodos de flutuação de Willis e centrífugo-flutuação em solução de sacarose. De 204 amostras, 45,6 por cento estavam positivas para helmintos gastrointestinais.

Physiological changes in Biomphalaria glabrata say, 1818 (Pulmonata: Planorbidae) caused by sub-lethal concentrations of the latex of Euphorbia splendens var. hislopii N.E.B (Euphorbiaceae)

Molluscides have been used as one of the strategies to control schistosomiasis. Many plant extracts with molluscidal effects have been tested, but the action of the latex of Euphorbia splendens var. hislopii is considered the most promising because it meets the recommendations of the World Health Organization (WHO). The objective of this study was to determine the lethal dose and identify the effects of the different doses of latex of E. splendens var. hislopii on the physiology of Biomphalaria glabrata submitted to treatment for 24 h. The concentrations of glucose, uric acid and total proteins in the hemolymph and of glycogen in the digestive gland and cephalopodal mass were determined. The LD50 value was 1 mg/l. The highest escape index was found to be at a concentration of 0.6 mg/l. The results showed that the latex of E. splendens var. hislopii caused a sharp reduction in the reserves of glycogen in the digestive gland and elevation of the protein content in the hemolymph of B. glabrata.

First report of Lymnaea cousini Jousseaume, 1887 naturally infected with Fasciola hepatica (Linnaeus, 1758) (Trematoda: Digenea) in Machachi, Ecuador

We report the first finding of Lymnaea cousini naturally infected with Fasciola hepatica in Ecuador. A sample of 70 snails was collected in April 2005 from a wetland located in a valley at approximately 3000 m a.s.l., near the locality of Machachi, Pichincha Province. The prevalence of natural infection in L. cousini was 31.43 percent, which is the highest value ever recorded for naturally infected lymnaeid species.

Activity of Euphorbia splendens var. hislopii N.E.B. (Euphorbiaceae) latex against Lymnaea columella (Say, 1817) (Pulmonata: Lymnaeidae), intermediate host of Fasciola hepatica, Linnaeus, 1758 (Trematoda: Fasciolidae). 2: limited field-testing

The molluscicidal evaluation of Euphorbia splendens var. hislopii (Crown of thorns) against Lymnaea columella snails, intermediate host of Fasciola hepatica, in irrigation ditches of the Pisciculture Station at Universidade Federal Rural do Rio de Janeiro, was studied under limited field conditions. An aqueous solution of the latex at 5 mg/l was tested in two irrigation ditches (experimental and control ditches), after initial sampling of the snail population present. Twenty-four hours after application of the product, it was verified that 97.4 percent of free L. columella snails and 100 percent of snails of the same species captive in cages and used as sentinels at three points equidistant from the application site in the experimental ditch, died. For Biomphalaria tenagophila and Melanoides tuberculata snails, present in the experimental ditch, the mortality was 100 percent, for the species Pomacea spp. the mortality was 40 percent. No mortality was verified in the free mollusks, or in the sentinels in the ditch used as control. E. splendens var. hislopii latex is thus an efficient natural molluscicide, which may be used as an alternative control agent against L. columella.

Molluscicidal activity of crown of Christ (Euphorbia splendens var. hislopii) (Euphorbiaceae) latex submitted to pH variation

Laboratory and field bioassays have confirmed the specificity of the molluscicidal activity of the Euphorbia splendens var. hislopii latex (crown of Christ) (Euphorbiaceae) over snails of the species Biomphalaria glabrata, B. tenagophila, B. straminea, B. pfeifferi and Bulinus sp. in the control of Schistosoma mansoni. In the present study, the effect of the pH variation on lethal concentration (LC90) over B. tenagophila was evaluated. Bioassays with the aqueous solutions of the latex ranging from 0.4 to 12 æl/l were adjusted for pH of 5.0; 6.0; 7.0 and 8.0, and tested in accordance with methods standardized by World Health Organization. The results obtained indicated that the minor concentration of the latex occurred at pH 6.0 (LC90 = 3.2 æl/l) and the maximum at pH 8.0 (LC90 = 10.3 æl/l). Lethal concentrations adjusted for pH 5.0 and 7.0 were 3.4 æl/l and 4,7æl/l, respectively. From the results it could be concluded that the molluscicidal toxicity was not altered when the concentrations were adjusted for pH 5.0 and 6.0, as we observed that mortality rate was 100 percent starting at a concentration of 2.0 æl/l, not the same for the concentrations with adjustment for pH 7.0 and 8.0

Molluscicidal action of the latex of Euphorbia splendens var. hislopii N.E.B. ("Christ's Crown") (Euphorbiaceae) against Lymnaea columella (Say, 1817) (Pulmonata: Lymnaeidae), intermediate host of Fasciola hepatica Linnaeus, 1758 (Trematode: Fasciolidae): 1- test in laboratory

The latex action of Euphorbia splendens var. hislopii (Christ's Crown) against snails Lymnaea columella, intermediate host of Fasciola hepatica, derived from irrigation ditches of the Station of Pisciculture at Universidade Federal Rural do Rio de Janeiro, was studied in the laboratory. Lab bioassays, using aqueous solutions of the latex, varying between 0.1 and 10 mg/l, have proven molluscicidal activity of the product collected on the same day the tests were performed, during the four seasons of the year, finding the following lethal concentrations (LC90): 1.51 mg/l in the spring; 0.55 mg/l in the summer; 0.74 mg/l in the fall and 0.93 mg/l in winter, after 24 h exposure of the snails, showing significant differences among the seasons of the year (ANOVA test, F = 11.01, G.L.= 3/33, p < 0.05), as well as among the concentrations (ANOVA test, F = 27.38, G.L.= 11/33, p < 0.05). In the summer, mortality reached 100 percent from concentration at 0.6 mg/l, the same during fall and in winter as of 1 mg/l, while in spring it only reached 100 percent mortality as of 2 mg/l. Mortality in the controls was low, reaching 5 percent in the summer and winter and 10 percent in the fall and spring. None of the samples died. During the assay, with an aqueous solution of the latex at a concentration of 5 mg/l, in order to check the time of duration of the product effect, in the laboratory, it was observed that the molluscicidal activity remained stable up to the 15th day after the beginning of the test with 100 percent mortality of L. columella, gradually losing its effect until the 23rd day, when we no longer observed animal mortality. In the control group, there was a random daily variation in mortality rate ranging 0-50 percent after 48 h of observation for 30 days

The molluscicidal activity of niclosamide (Bayluscide WP70®) on Melanoides tuberculata (Thiaridae), a snail associated with habitats of Biomphalaria glabrata (Planorbidae)

The aim of this study was to determine the toxicity of niclosamide (Bayluscide ®) on Melanoides tuberculata and Biomphalaria glabrata under laboratory conditions. The latter species is the intermediate host of Schistosoma mansoni (Sambon 1917). M. tuberculata was successfully used as competitor of B. glabrata in biological control programs in French West Indies. Both molluscicide and biological control using M. tuberculata have proved to be successful in reducing the population density of B. glabrata. The associated use of molluscicide in this area would be an effective measure if M. tuberculata were less susceptibility to the molluscicide than B. glabrata. Three hundreds individuals each of B. glabrata and of M. tuberculata, collected in Sumidouro, State of Rio de Janeiro, were used in the experiment. The molluscs were exposed to 14 different concentrations of niclosamide as recommended by the World Health Organization. Probit analysis was used to determine the LC 50 and LC 90. The LC 50 and LC 90 values for B. glabrata were 0.077 mg/l and 0.175 mg/l, respectively and the LC 50 and LC 90 values for M. tuberculata were 0.082 mg/l and 0.221 mg/l respectively. As the lethal concentrations of niclosamide were approximately the same to both species, this could be a disadvantage when controlling B. glabrata with niclosamide in an area of M. tuberculata occurrence. It migth therefore be preferable to utilize the latex extracted from the Euphorbia splendens, which presented a much higher efficiency for B. glabrata than to M. tuberculata

Infecçäo experimental de Physa cubensis Pfeiffer 1839 e Lymnaea columella com miracídios de Fasciola hepatica Linnaeus, 1758 / Experimental infection of Physa cubensis Pfeiffer, 1839 and Lymnaea columella with Fasciola hepatica miracidiae Linnaeus, 1758

Foi realizada a infecçäo experimental de Physa cubensis Pfeiffer, 1839, com miracídios de Fasciola hepatica. Para tanto, cada um dos cem moluscos, selecionados para o experimento, foram infectados com três miracídeos. Alguns exemplares, escolhidos ao acaso, foram mantidos até o 60º dia para observaçäo da emergência de formas larvais. Os moluscos restantes foram fixados após 0,5; 1; 2; 3; 4; 5; 24; 48; 72; 96; 120 e 144 horas de infecçäo, utilizando Raillet & Henry. O trabalho foi realizado de forma comparativa com Lymnaea columella. Os resultados demonstraram o desenvolvimento das formas larvais do trematódeo em L. columella e a presença de esporocistos em vários estágios de degeneraçäo na regiäo cefalopodal e na regiäo do manto nos primeiros dias de infecçäo em P. cubensis

Alteraçöes histológicas em Lymnaea columella provocadas pelo látex de Euphorbia splendens var. hislopii / Histological changes in Lymnaea columella caused by the Euphorbia splendens's latex

Observaçöes histológicas em moluscos da espécie Lymnaea columella foram realizadas para determinar a existência ou näo de alteraçöes provocadas pelo uso do látex de Euphorbia splendens var. hislopii. O experimento foi realizado de acordo com os métodos padronizados pela OMS. Cinqüenta exemplares de L. columella, com comprimento de concha de 6±1mm, foram submetidos a 200ml das soluçöes nas concentraçöes de 0,47µl/L; 0,76µl/L; 0,94µl/L e 1,51µl/L, durante 24 horas. Após o evento experimental, os moluscos foram colocados em soluçäo de Raillet & Henry, para sacrifício e fixaçäo. Os resultados demonstraram lesöes caracterizadas por degeneraçäo, necrose e acúmulo de líquido na glândula digestiva e no rim, em exemplares submetidos a concentraçöes a partir de 0,47 mil/L

Ocorrência de Achatina fulica no Vale do Paraíba, Estado do Rio de Janeiro, Brasil / Occurrence of Achatina fulica in the Vale do Paraíba, Rio de Janeiro state, Brazil

Registrou-se no Município de Resende, Estado do Rio de Janeiro, Brasil, a primeira ocorrência do molusco Achatina fulica hospedeiro intermediário de Angiostrongylus cantonensis, causador da angiostrongilíase meningoencefálica. Em cinco bairros visitados, foram encontrados moluscos vivendo livremente, e nenhum dos animais coletados apresentava a forma larvar do parasito. A presença de Achatina fulica pode estar relacionada à comercializaçäo desse molusco como alimento, e representa possibilidade de instalaçäo dessa zoonose na regiäo

The molluscicidal activity of the latex of Euphorbia splendens var. hislopii on Melanoides tuberculata (Thiaridae), a snail associated with habitats of Biomphalaria glabrata (Planorbidae)

The use of the latex of Euphorbia splendens var. hislopii was considered as an effective control method for Biomphalaria glabrata in Sumidouro, Rio de Janeiro. However, the appearance and expansion of the snail Melanoides tuberculata since August 1997, with the concomitant reduction of the population of B. glabrata suggest that competitive exclusion might be taking place. Depending on the susceptibility of the thiarid to the E. splendens toxin, the natural control that is occurring could be interrupted by the employment of the latex if the planorbid were less susceptible to the toxin. The aim of this study is to investigate the molluscicidal activity of the latex on M. tuberculata. We used 420 M. tuberculata, from Sumidouro. Fourteen different latex concentrations were tested using World Health Organization general methodology. Probit analysis was used for LD90 and LD50 determination. The LD50 was 3.57 mg/l and LD90 was 6.22 mg/l. At the highest concentration (10 mg/l) there was no survival. No significant differences among replicas (chi2 = 8.31; gl = 13; p > 0.05) were found. The LD90 dose for M. tuberculata was 13.8 times greater than that for B. glabrata, so that the molluscicide in the presence of the thiarid may have a synergic effect on reduction of Biomphalaria populations

Fasciolose bovina: controle com látex da "coroa-de-Cristo" (Euphorbia splendens var. hislopii) / Bovine fascioliasis: control with Christ's crown latex (Euphorbia splendens var. hislopii)

Foi avaliada a utilizaçäo do látex da "coroa-de-Cristo" (Euphorbia splendens var. hislopii) no controle da fasciolose hepática. A avaliaçäo foi feita analisando a disponibilidade de metacercárias na pastagem, utilizando animais traçadores numa fazenda de gado de corte no município de Taubaté, Säo Paulo, Brasil. Os resultados obtidos, examinando fezes de 60 animais através da técnica de Quatro Tamises, demonstraram uma queda significativa na prevalência da infecçäo durante a experiência, indicando mais um subsídio no controle do problema

Evaluation of temporal, seasonal and geographic stability of the molluscicidal property of Euphorbia splendens latex

Laboratory tests with aqueous solutions of Euphorbia splendens var. hislopii latex have demonstrated seasonal stability of the molluscacidal principle, with LD90 values of 1.14 ppm (spring), 1.02 ppm (fall), 1.09 ppm (winter), and 1.07 ppm (summer) that have been determined against Biomphalaria tenagophila in the field. Assays on latex collected in Belo Horizonte and Recife yielded LD90 values similar to those obtained with the reference substance collected in Rio de Janeiro (Ilha do Governador), demonstrating geographic stability of the molluscacidal effect. The molluscacidal action of aqueous dilutions of the latex in natura, centrifuged (precipitate) and lyophilized, was stable for up to 124 days at room temperature (in natura) and for up to 736 days in a common refrigerator at 10 to 12 degrees C (lyophilized product). A 5.0 ppm solution is 100% lethal for snails up to 13 days after preparation, the effect being gradually lost to almost total inactivity by the 30th day. This observation indicated that the active principle is instable. These properties together with the wide distribution of the plant, its resistance and adaptation to the tropical climate, its easy cultivation and the easy obtention of latex and preparation of the molluscicidal solution, make this a promising material for large-scale use in the control of schistosomiasis