Immunoprotective Effect of Chitosan Particles on Hymenolepis nana - Infected Mice.

Hymenolepis nana is the most commonly known intestinal cestode infecting mainly human. This study aimed to investigate the potential effect of chitosan particles (CSP) to enhance the immune system against H. nana infection. Determination of worm burden, egg output, histopathological changes, oxidative stress markers (lipid peroxidation and reduced glutathione), goblet (GCs) and mucosal mast cells (MMCs) counts in intestinal ileum was performed. In addition, levels of intestinal mRNA expression of interleukin (IL)-4, IL-9, stem cell factor (SCF), type I and II interferons (IFN)-α/ γ, tumour necrosis factor (TNF)-α, mucin 2 (MUC2) and inducible nitric oxide synthase (iNOs) were investigated using real-time PCR. The results indicated induced reductions in adult worm and egg counts in infected mice after CSP treatment. This was associated with improvement in tissue morphometric measurements and oxidative stress which were altered after infection. Expression levels of iNOs, IFN-α, IFN-γ, TNF-α and IL-9 were decreased by CSP. Conversely, expression levels of MUC2, IL-4 and SCF increased compared to infected untreated group. In addition, GCs and MMCs counts were normalized by CSP. In conclusion, this study could indicate the immunoprotective effect of CSP against H. nana infection. This was characterized with Th2 anti-inflammatory responses.

Effect of Mass Stool Examination and Mass Treatment For Decreasing Intestinal Helminth and Protozoan Infection Rates in Bolivian Children: A Cross-Sectional Study.

Bolivia is one of the countries with a high intestinal helminth and protozoan infection rate. Despite the high prevalence of the parasitic infection, nationwide preventive measures for Bolivian children have not yet been implemented. We evaluated the effect of mass stool examination and treatment as a strategy for decreasing the infection rate. This study was conducted between 2013 and 2015 in children aged 2-18 years. A total of 2,033 stool samples (575 in 2013, 815 in 2014 and 642 in 2015) were collected and examined using the formalin-ether medical sedimentation method. As an anthelminthic medicine, nitazoxanide was given to all infected children within 2 months post-examination, each year. The effect of mass stool examination and treatment was evaluated based on the changes in the overall or individual parasitic infection rates during the study period. The overall parasitic infection rate decreased significantly from 65.2% in 2013 to 43.0% in 2015; a 22.2 percentage point decrease (P<0.001). Protozoan infection accounted for a large portion of the parasitic infections, in the following rates: 62.4% in 2013, 49.3% in 2014, and 41.0% in 2015. The rate of the most common helminth infection, Hymenolepis nana, decreased significantly from 9.0% in 2013 to 6.4% in 2014 to 3.4% in 2015 (P<0.001). Prevalence of the most common pathogenic protozoan infection, Entamoeba histolytica, decreased significantly from 19.0% in 2013 to 3.0% in 2015 (P<0.001). Conversely, the rate of Giardia intestinalis increased significantly from 16.5% in 2013 to 21.2% in 2015 (P<0.01). Mass stool examination and treatment for intestinal helminth and protozoan infections was effective for decreasing the overall parasitic infection rate in the study population, excluding Giardia intestinalis. Further studies on the long-term effect of mass stool examination and treatment for decreasing all intestinal parasitic infection rates in Bolivian children are needed.

Analysis of a child infected with Hymenolepis diminuta in Poland.

Hymenolepis diminuta is a cosmopolitan parasite of rats and mice which is very rare in humans. This study presents the case of a 3-year-old boy infected with Hymenolepis diminuta in Poland. The diagnosis was based on eggs found and their morphology in the patient's stool.

Immunization of rodents against Hymenolepis infections using non-viable homologous oncospheres.

Immunity to Taiwan Taenia infection in pigs can be stimulated using homologous or heterologous non-viable Taenia oncospheres. This study was designed to determine whether homologous non-viable oncospheres could stimulate immunity to Hymenolepis infection in rodents. Hatched oncospheres were prepared from eggs of Hymenolepis diminuta, Hymenolepis nana, and Hymenolepis microstoma and kept at -70 degrees C for more than 1 month. A mixture of 500 non-viable oncospheres of each tapeworm and complete Freund's adjuvant was injected subcutaneously in four groups of Sprague-Dawley rats or ICR mice one to four times at an interval of 1 week; controls were not immunized. After immunization, each rodent was orally inoculated with three fresh active cysticercoids of H. diminuta or H. microstoma or 500 fresh eggs of H. nana. The animals were then necropsied for adult tapeworms. No rats or mice immunized with non-viable oncospheres of H. diminuta or H. nana were infected by the challenge inoculation. However, 28 of 34 mice immunized with non-viable H. microstoma oncospheres were infected after inoculation with cysticercoids. This study demonstrated complete protection against infection by homologous parasites in rats or mice immunized with non-viable oncospheres of H. diminuta and H. nana, respectively. Repeated immunization may not be required if resistance is stimulated in rodent hosts.

Importance of interferon-gamma in protective immunity against Hymenolepis nana cysticercoids derived from challenge infection with eggs in BALB/c mice.

The function of cytokines produced during Hymenolepis nana egg infection in mice in protective immunity against re-infection was examined. Treatment of mice with monoclonal antibody (MAb) against mouse interferon (IFN)-gamma caused suppression of protective immunity against H. nana re-infection when the MAb was injected intraperitoneally at a daily dose of 40.0 mg kg-1 during the effector phase of protective immunity. Although high levels of IFN-gamma, tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta were released into the intestinal tracts of the parasitised mice at challenge infection, there was almost no release of these cytokines in mice treated with the MAb. Daily administration of rolipram failed to suppress the protective immunity, even when 400 micrograms kg-1 of the agent was administered into mice during the effector phase of immunity. Treatment of mice with rolipram completely suppressed both TNF-alpha and IL-1 beta production in intestinal tracts, induced by H. nana challenge infection. However, endogenous IFN-gamma production in the intestine was scarcely affected by rolipram. These results strongly suggest that IFN-gamma is the most important (or essential) cytokine in protective immunity to H. nana re-infection, rather than TNF-alpha and IL-1 beta.

Immunity to adult cestodes: basic knowledge and vaccination problems. A review.

Immunity in mammals to intestinal cestodes has been reviewed using the normal final host infected with the tapeworms Hymenolepis diminuta in rats and H. microstoma and H. nana in mice as a model. Primary infections up to a certain level continue to live as long the host, while most worms in infections with larger doses are destrobilated and expelled. It has been argued that concomitant immunity against a superimposed infection exists in rats and mice infected with H. diminuta and H. microstoma, respectively, and suggested that it also takes place in humans infected with Taenia spp. Immunity to secondary infections after expulsion of a primary infection occurs, but immunological memory is rather short-lived, although depression of worm growth occurs for at least two third of the rat's life. Serum antibodies have been shown to produce a direct precipitate on the surface of cestodes in vitro, but a direct effect of antibodies in vivo or the relationship with e.g. host effector cells, like mast cells and eosinophils, is unknown. It has been shown that peritoneal exudate cells from rats are able to kill H. diminuta in vitro. Very little is known about the mechanisms of tapeworms to counteract host immunological responses, but the tegumental glycoconjugates and discoidal secretory bodies are possible candidates. Passive transfer of immunity by mesenteric lymph node cells has only been successful using cells from H. nana egg-infected mice and has shown that only short-lived proliferating cells are responsible for transferring immunity. Vaccination procedures and problems are discussed with special reference to E. granulosus in dogs.

Adoptive transfer of immunity with peritoneal exudate cells to the cestode Hymenolepis nana.

Under certain conditions, peritoneal exudate cells (PEC) removed from Hymenolepis nana-eggs infected mice, transferred to normal recipients severely inhibited the establishment of worms from a challenge infection, as expected in an immune state. A close relationship was observed between numbers of challenge worms and immune response. A significant effect was clearly demonstrable when the highest dose of eggs (150) was used, but the effect was less and not significant different when a smaller doses (30) was administered.

Tentativa de erradicaçäo da hemenolepíase em uma comunidade semifechada, empregando-se praziquantel / Attempt of eradication of hymenolepiasis in a semi-closed community using praziquantel

Duas semanas após o insucesso da terapêutica com mebendazol - 400 mg diários durante quatro dias consecutivos -, 101 indivíduos de uma comunidade semifechada, 50,5% infectados por Hymenolepis nana, em sua maioria crianças entre dois e seis anos de idade, foram tratados com praziquantel (*) em duas doses orais de 20 a 25 mg/Kg, administradas com dez dias de intervalo. O diagnóstico da himenolepíase, bem como os controles de cura parasitológica realizados nos 7, 14, 21, 30, 60 e 90 dias depois da administraçäo da segunda dose de praziquantel, basearam-se em exames de fezes pelo método quantitativo de KATO/KATZ. A tolerância ao medicamento foi excelente e a negativaçäo dos exames ocorreu independentemente da intensidade do parasitismo. Nos 7 e 14 dias pós-tratamento encontraram-se ovos de H. nana, respectivamente em nove e em dois pacientes, mas esses ovos apresentavam-se distorcidos. No controle do 21 dia todos os resultados mostraram-se negativos, traduzindo um índice de cura de 100%. A partir do 30 dia verificou-se em três crianças a eliminaçäo de ovos normais do parasita. Tendo em vista serem essas as únicas que viviam em regime de semi-internaçäo nessa comunidade e a positividade tardia dos exames, esses casos foram considerados como reinfecçäo. Conclui-se, pelos resultados alcançados, que o esquema posológico empregado, fundamentado nas investigaçöes experimentais conduzidas por CAMPOS & col. (1983), é eficaz e seguro para o tratamento da himenolepíase, em especial, quando se pretende tentar erradicá-la numa comunidade fechada

Tentativa de controle de himenolepíase devida a Hymenolepis nana por meio do praziquantel, em coletividade semifechada / Attempt to control hymenolepiasis caused by Hymenolepis nana by means of praziquantel, in a semi-closed community

Em virtude de sugestäo decorrente da investigaçäo experimental, foi usado o praziquantel, através de duas administraçöes intervaladas por dez dias, como tentativa para controlar a himenolepiase devida a Hymenolepis nana, em coletividade semifechada. Houve emprego, em cada oportunidade de 25 mg/kg, tendo ficado comprovada a validade dessa conduta, a despeito da ocorrência de raras positivaçöes interpretadas como reinfecçöes, durante o seguimento. O presente estudo afigura-se importante no contexto das medidas destinadas a combater globalmente e himenolepiase em apreço, em comunidades fechadas ou semifechadas diante da possibilidade de aproveitamento da elevada atividade curativa do praziquante

Praziquantel for control of Hymenolepis nana in mice.

Praziquantel was blended into ground mouse feed at 35, 70, and 140 ppm in one replicate and at 140, 210, and 280 ppm in a second replicate. Mice naturally infected with Hymenolepis nana were provided this diet for 7 consecutive days. Reduction of Hymenolepis nana in mice receiving medicated feed when compared to mice receiving nonmedicated feed was 48.9, 73.2, and 87.1%, respectively in replicate 1, and 100% in all three groups in replicate 2. These data suggest that praziquantel blended into the feed at 140 ppm for 7 consecutive days will provide efficacious (87.1-100%) control of Hymenolepis nana in mice. Higher dosages may be necessary for complete elimination of this parasite.