Cholinergic signaling plasticity maintains viscerosensory responses during Aspiculuris tetraptera infection in mice small intestine.

Intestinal parasites alter gastrointestinal (GI) functions like the cholinergic function. Aspiculuris tetraptera is a pinworm frequently observed in laboratory facilities, which infests the mice cecum and proximal colon. However, little is known about the impact of this infection on the GI sensitivity. Here, we investigated possible changes in spontaneous mesenteric nerve activity and on the mechanosensitivity function of worm-free regions of naturally infected mice with A. tetraptera. Infection increased the basal firing of mesenteric afferent nerves in jejunum. Our findings indicate that nicotinic but not muscarinic receptors, similarly affect spontaneous nerve firing in control and infected animals; these axons are mainly vagal. No difference between groups was observed on spontaneous activity after nicotinic receptor inhibition. However, and contrary to the control group, during infection, the muscarinic signaling was shown to be elevated during mechanosensory experiments. In conclusion, we showed for the first time that alterations induced by infection of the basal afferent activity were independent of the cholinergic function but changes in mechanosensitivity were mediated by muscarinic, but not nicotinic, receptors and specifically by high threshold nerve fibers (activated above 20mmHg), known to play a role in nociception. These plastic changes within the muscarinic signaling would function as a compensatory mechanism to maintain a full mechanosensory response and the excitability of nociceptors during infection. These changes indicate that pinworm colonic infection can target other tissues away from the colon.

Syphacia obvelata modifies mitogen-activated protein kinases and nitric oxide synthases expression in murine bone marrow cells.

Syphacia obvelata is a rodent nematode parasite with high prevalence in laboratory mice. In our previous work we have demonstrated that this gut-dwelling helminth induces significant hematopoietic changes, characterized by increased myelopoiesis and erythropoiesis in infected animals, and accompanied with altered reactivity of bone marrow hematopoietic progenitors to interleukin (IL)-17. In this study we extended these investigations by demonstrating that naturally acquired S. obvelata infection induces significant alterations in murine bone marrow cells manifested at the molecular level. Namely, S. obvelata infection induced sustained phosphorylation of the members of three major groups of distinctly regulated mitogen-activated protein kinases (MAPKs), the p38, the c-Jun amino-terminal kinase (JNK) and the extracellular signal-regulated kinase (ERK), as well as enhanced expression of mRNA for the inducible nitric oxide synthase (iNOS) in the bone marrow cells of infected animals. Furthermore, the infection interfered with the IL-17-mediated effects in bone marrow cells, since in normal mice IL-17 significantly enhanced phosphorylation of p38 MAPK and upregulated the expression of iNOS and the constitutive, endothelial (e)NOS mRNA, while in S. obvelata-infected animals IL-17 did not influence the MAPKs activation, but markedly down-regulated the expression of both NOS isoforms. The data obtained demonstrating that S. obvelata is able to manipulate signal transduction pathways in the hosts' bone marrow cells, pointed to the multiple layers of immunomodulatory ability of this pinworm parasite and highlighted the importance of working under pinworm-free conditions when using experimental murine models for immunohematopoietic investigations.

Syphacia obvelata infections and reproduction of male domestic mice Mus musculus domesticus on a sub-Antarctic Island.

The reproductive activity of feral male mice on an island of the sub-Antarctic Kerguelen archipelago was influenced by biological factors depending on periods within the breeding season. After having controlled host reproductive activity indices for body size, i.e. age, and body condition effects, Syphacia obvelata prevalence did not vary with host reproductive status or age either during the beginning or the middle-end of the reproductive season. Considering the beginning of the breeding season, worm abundance was more pronounced in males the year following a strong winter crash of the population than in years when high over wintering survival occurred. During the middle-end of the breeding season, males with the highest reproductive status were more infected than males with a lower reproductive status in years when oldest individuals dominated the population. It is suggested that this situation was due to an endocrine related increased host susceptibility partly influenced by a change in the age structure of the population, and that an increase in worm transmission was not directly related to male activity concurrent with reproductive status, nor to population density.

Subsensitivity to beta-adrenergic stimulation in atria from rats infested with Syphacia sp.

Syphacia sp. is a common intestinal parasite in conventionally-housed laboratory rodents. Although gross lesions are rare in oxyuriasis, it is possible that more subtle changes may develop, which may affect research results. In this study, we analysed the responsiveness to beta-adrenergic stimulation by isoproterenol (ISO) of left atria isolated from Syphacia-infested (SYPH) and control, non-infested adult male Wistar rats (CONT). In the non-infested animals, ISO pD(2) was not significantly changed by ivermectin treatment. Whereas the maximal inotropic response to ISO was not significantly affected, the pD(2) value was decreased in SYPH (7.61 +/- 0.09, n = 7, vs 8.21 +/- 0.25 in CONT, n = 5, P < 0.05), indicating lower sensitivity to beta-adrenergic stimulation. This change was similar to that caused by a classic stressor, namely repeated immobilization, in non-infested rats (IMMO). In this group, ISO pD(2) was 7.62 +/- 0.14, n = 6 (P < 0.05 with relation to CONT). The results indicate that infestation with Syphacia sp. is as effective as immobilization at diminishing cardiac reactivity to beta-adrenergic stimulation. It is thus possible that oxyuriasis may affect the response of other tissues to physiological modulators.

Parasitose intestinal: profilaxia e tratamento dessa esquecida realidade brasileira / Intestinal parasite: prophylaxis and treatment of that forgotten brazilian reality

Com o evoluir da Medicina, inúmeras técnicas, métodos de diagnóstico e tratamento foram surgindo para as novas doenças constantemente descobertas. E, nessa realidade, com freqüência deparamo-nos com médicos capazes de tratar doenças complexas, com tecnologias modernas. Porém muitos se esquecem de considerar doenças básicas da comunidade, como é o caso das parasitoses intestinais, uma realidade brasileira que, embora prevalecente nas camadas socioeconomicamente menos favorecidas, afeta todos os níveis sociais. A finalidade deste artigo é promover uma revisão bibliográfica sobre o tema e abordar as principais parasitoses, dando subsídio ao diagnóstico, e, principalmente, frisar a conscientização da necessidade das medidas preventivas

The effect of Toxoplasma gondii and other parasites on activity levels in wild and hybrid Rattus norvegicus.

Using both correlational and experimental evidence, the relationship between parasite load and host activity was assessed in brown rats, Rattus norvegicus. Two hypotheses were tested--(1) that parasites with indirect life-cycles, involving transmission between a prey and its predator, will alter the activity of the intermediate host so as to increase its susceptibility to predation by the definitive host and (2) that activity levels in parasitized rats would be increased rather than decreased. Four groups of rats (n = 140) were examined. One group (n = 50) were wild brown rats trapped from 3 UK farmsteads, with naturally occurring parasites. The others were purpose-bred wild/laboratory hybrid rats with experimentally induced parasitic infections of either (n = 15) adult-acquired or (n = 15) congenitally-acquired Toxoplasma gondii (an indirect life-cycle parasite), or (n = 15) Syphacia muris (a direct life-cycle parasite). Uninfected hybrid rats ( n = 45), matched for sex, age and weight, served as controls. Rats were housed individually in outdoor cages, and their activities were recorded on video-tapes for 6 non-consecutive 10 h nights. Exercise wheels were also available for the hybrid rats. Out of 6 parasite species detected in the wild rats, T. gondii was the only one which required predation by a definitive host to complete its life-cycle, and was also the only parasite to be associated with higher activity levels in infected than uninfected rats. Hybrid rats infected with T. gondii were also more active than those uninfected, whereas there were no differences in activity levels between S. muris infected and uninfected rats. This study shows that the indirect life-cycle parasite T. gondii can influence the activity of its intermediate host the rat. I suggest that this may facilitate its transmission to the cat definitive host.

Enterobiasis en alumnos del centro poblado Menor Herbay Alto, Cañete, Julio 1987 / Enterobiasis in school children of \"Centro Poblado Menor Herbay Alto, Cañete\", July 1987

Se ha realizado una encuesta parasitológica para buscar Enterovius vermicularis en una población escolar del "Centro Poblado Hervay Alto, Cañete". Se encuestó a 368 niños entre los 3 y 11 años de edad; se aplicó la prueba de Graham, encontrándose 255 (68.3 por ciento) positivos. En 50 por ciento de los casos positivos y a sus familiares se les dió tratamiento con resultado exitoso. Se trata de explicar la alta prevalencia de la enterobiasis en población escolar de la zona por la deficiencia del saneamiento ambiental, la precaria calidad de la vivienda, el hacinamiento, así como la baja condición socio-económica de la población. Se plantea que estos serían aspectos importantes en la prevención y control de este parasitismo

[The characteristics of the acid-forming function of the stomach in patients with duodenal peptic ulcer combined with intestinal parasitoses]. / Osobennosti kislotoobrazuiushchei funktsii zheludka u bol'nykh s iazvennoi bolezn'iu dvenadtsatiperstnoi kishki, sochetaiushcheisia s kishechnymi parazitozami.

The paper summarizes the results of the studies of gastric secretion in patients with duodenal ulcers alone and in patients with duodenal ulcers accompanied by gastric parasitoses. The findings indicate that gastric secretion values in patients with duodenal ulcers accompanied by gastric parasitoses tend to decrease. The features of gastric secretion in such patients should be taken into consideration during their pathogenetic treatment (H2-blockers of histamine receptors).

[The comparative characteristics of the ontogenetic indices in healthy children and those with enterobiasis]. / Sravnitel'naia kharakteristika nekotorykh pokazatelei ontogeneza zdorovykh i bol'nykh énterobiozom detei.

It should be noted that a total number of dysembryogenesis stigmas in an individual child must be taken into consideration in the formation of risk groups. Children with an increased number of stigmas (more than 7 in one child) are thought to be at high risk only of somatic pathology but also of the given helminthiasis and should be urgently examined for enterobiasis.

Prurito anal, nasal, bruxismo y sialorrea en niños con enterobiasis o ascariasis / Anal and nasal pruritus, bruxism and sialorrhea in children with enterobiasis or ascariasis

Se estudiaron 120 niños en edades comprendidas entre 1 y 14 años. Se dividieron en cuatro grupos constituídos por 30 niños cada uno. Grupo 1. pacientes con enterobiasis pura: Grupo 2, pacientes con ascariasis pura; Grupo 3, pacientes con giardíasis y Grupo 4, niños sin parasitosis. A todos se les practicó coproparasitoscópico por los métodos de Faust y Graham, todos en series de tres. Los resultados se procesaron estadísticamente por la prueba de X2 y se encontró significación en el caso de enterobiasis (prurito nasal, bruxismo y sialorrea); no hubo significación estadística de estos síntomas en el caso de pacientes con giardiasis o niños sin parasitosis. Se concluye que en niños que presenten los sintomas citados, se efectúe diagnóstico presuncional de enterobiasis y/o ascariasis, comprobándose por exámenes parasitoscópicos