Different inoculum loads of Toxoplasma gondii induce reduction of myenteric neurons of the rat colon / Diferentes inóculos de Toxoplasma gondii induzem a redução de neurônios mioentéricos no cólon de ratos

Abstract Toxoplasmosis, a disease caused by Toxoplasma gondii, is an important health problem, especially in immunocompromised hosts. T. gondii uses the gut wall as an infection gateway, with tropism for muscular and nervous tissues causing intestinal alterations, including some in the enteric nervous system. This study aims at investigating the colon of rats infected by T. gondii in order to understand how the amount of oocysts influences in myenteric neuronal changes. Sixty Wistar rats (Rattus norvegicus) were divided into six groups. One group remained as a control and the others received inocula of 10, 50, 100, 500 or 5,000 oocysts of T. gondii. The animals were euthanized after 30 days of infection. The total neuronal population and the nitrergic subpopulation in the colon myenteric plexus of each animal was counted. The data were statistically analyzed showing less weight gain in rats with 10, 500 and 5,000 oocysts. A decrease in the number of total neurons with 50, 100 or 5,000 oocysts and an increase in the nitrergic population with 10, 100, 500 or 5,000 oocysts were verified. These results show that neuronal alterations are more significant when the infection is induced by larger inocula and reinforces the suspicion that neuronal loss is directed at cholinergic neurons.

Resumo A toxoplasmose, doença causada pelo Toxoplasma gondii, é um importante problema de saúde, principalmente em imunocomprometidos. T. gondii utiliza a parede do intestino como porta de entrada no hospedeiro e tem tropismo pelos tecidos muscular e nervoso provocando alterações intestinais, inclusive no sistema nervoso entérico. Este estudo buscou analisar o cólon de ratos infectados por T. gondii para entender como a quantidade de oocistos influencia nas alterações neuronais mientéricas. Foram utilizados 60 ratos Wistar (Rattus norvegicus) em seis grupos. Um dos grupos permaneceu como controle e os demais receberam inóculos de 10, 50, 100, 500 ou 5.000 oocistos de T. gondii. Os animais foram submetidos a eutanásia após 30 dias de infecção. No plexo mientérico do cólon dos animais foram quantificadas a população neuronal total e a subpopulação nitrérgica. Os dados foram analisados estatisticamente demonstrando inferior ganho de peso nos ratos com 10, 500 e 5.000 oocistos. Verificamos diminuição no número de neurônios totais com inóculos de 50, 100 ou 5.000 oocistos e aumento da população nitrérgica com 10, 100, 500 ou 5000 oocistos. Estes resultados mostram que alterações neuronais são mais significativas quando a infecção é induzida por inóculos maiores e reforça a suspeita de perda neuronal direcionada a neurônios colinérgicos.

Myenteric plexus is differentially affected by infection with distinct Trypanosoma cruzi strains in Beagle dogs

Chagasic megaoesophagus and megacolon are characterised by motor abnormalities related to enteric nervous system lesions and their development seems to be related to geographic distribution of distinct Trypanosoma cruzi subpopulations. Beagle dogs were infected with Y or Berenice-78 (Be-78) T. cruzi strains and necropsied during the acute or chronic phase of experimental disease for post mortem histopathological evaluation of the oesophagus and colon. Both strains infected the oesophagus and colon and caused an inflammatory response during the acute phase. In the chronic phase, inflammatory process was observed exclusively in the Be-78 infected animals, possibly due to a parasitism persistent only in this group. Myenteric denervation occurred during the acute phase of infection for both strains, but persisted chronically only in Be-78 infected animals. Glial cell involvement occurred earlier in animals infected with the Y strain, while animals infected with the Be-78 strain showed reduced glial fibrillary acidic protein immunoreactive area of enteric glial cells in the chronic phase. These results suggest that although both strains cause lesions in the digestive tract, the Y strain is associated with early control of the lesion, while the Be-78 strain results in progressive gut lesions in this model.

A Case of Echinostoma cinetorchis (Trematoda: Echinostomatidae) Infection Diagnosed by Colonoscopy

Human cases of echinostomiasis have been sporadically diagnosed by extracting worms in the endoscopy in Korea and Japan. Most of these were caused by Echinostoma hortense infection. However, in the present study, we detected 2 live worms of Echinostoma cinetorchis in the ascending colon of a Korean man (68-year old) admitted to the Gyeongsang National University Hospital with complaint of intermittent right lower quadrant abdominal pain for 5 days. Under colonoscopy, 1 worm was found attached on the edematous and hyperemic mucosal surface of the proximal ascending colon and the other was detected on the mid-ascending colon. Both worms were removed from the mucosal surface with a grasping forceps, and morphologically identified as E. cinetorchis by the characteristic head crown with total 37 collar spines including 5 end-group ones on both sides, disappearance of testes, and eggs of 108x60 microm with abopercular wrinkles. The infection source of this case seems to be the raw frogs eaten 2 months ago. This is the first case of endoscopy-diagnosed E. cinetorchis infection in Korea.

Heavy Hymenolepis nana Infection Possibly Through Organic Foods: Report of a Case

We encountered a patient with heavy Hymenolepis nana infection. The patient was a 44-year-old Korean man who had suffered from chronic hepatitis (type B) for 15 years. A large number of H. nana adult worms were found during colonoscopy that was performed as a part of routine health screening. The parasites were scattered throughout the colon, as well as in the terminal ileum, although the patient was immunocompetent. Based on this study, colonoscopy may be helpful for diagnosis of asymptomatic H. nana infections.

Enterobius vermicularis Eggs Discovered in Coprolites from a Medieval Korean Mummy

While the presence of pinworm eggs in archaeological samples has been reported by many researchers in the New World, those have been detected very scarcely in the Old World, especially in East Asian countries. In fact, many parasite species were recovered from the archeological remains in Korea, eggs of Enterobius vermicularis had not been found. Recently, a female mummy buried in the 17th century was discovered in the Joseon tomb from Dangjin-gun, Chungcheongnam-do, Korea. After rehydration process for 12 days, investigations were carried on the luminal surface of the colon. From them, 3 eggs of E. vermicularis were recovered. They were elliptical, transparent with a thin egg shell, 50.3+/-5.2 microm (length) and 28.2+/-3.9 microm (width) in size. This is the first discovery of E. vermicularis eggs in East Asia.

A case of colonic lymphoid tissue invasion by Gymnophalloides seoi in a Korean man

A 65-year old Korean man, living in Mokpo-city, Jeollanam-do, Republic of Korea, visited a local clinic complaining of right upper quadrant pain and indigestion. At colonoscopy, he was diagnosed as having a carcinoma of the ascending colon, and thus, a palliative right hemicolectomy was performed. Subsequently, an adult fluke of Gymnophalloides seoi was incidentally found in a surgical pathology specimen of the lymph node around the colon. The worm was found to have invaded gut lymphoid tissue, with characteristic morphologies of a large oral sucker, a small ventral sucker, and a ventral pit surrounded by strong muscle fibers. This is the first reported case of mucosal tissue invasion by G. seoi in the human intestinal tract.

Diversidade das infracomunidades de estrongilídeos do cólon dorsal de equus caballus do estado do Rio de Janeiro Brasil / Diversity of strongylid infracommunities of dorsal colon equus caballus from Rio de Janeiro state Brazil

Vinte e três espécies de nematóides estrongilídeos (18 Cyathostominae e cinco Strongylidae) foram coletadas de alíquotas, com aproximadamente, 10 por ciento do cólon dorsal de 33 eqüinos, provenientes da região de Janeiro. Cylicostephanus Longibursatus (90,9 por ciento; 1.078,4) C. goldi (81,8 por ciento; 236,9) e Cylicocyclus nassatus (75,8 por ciento; 39,1) foram as espécies mais prevalentes e com maior abundância média, respectivamente. Cylicostephanus longibur-satus apresentou o maior Ïndice de Dispersão (2.524.1) e menor Índice de Green (0,1), devido á presenca em quase todas as infracomunidades, e ao baixo nível de agregacã dos espécimes nas mesmas. Cinco infracomunidades (2, 3, 11, 24 e 25) apresentaram riqueza parasitária igual a quatro, porém os índice de Shannon e de uniformadade de Pielou foram distintos, devido á equitabilidade das infrapopulacões

Helmintofauna do cólon dorsal de equídeos provenientes do estado de Pernambuco Brasil / Helminthic fauna of the dorsal colon of equids from the Pernambuco state Brazil

Foram identificados 1,521 nematóides recuperados das amostras correspondentes a 10 por cento do conteúdo do cólon dorsal de seis equídeos naturalmente infectados provenientes do Estado de Pernambuco. Destes, 1,505 foram espécimes adultos da subfamilia Cyathostominae que estiveram distribuídos em 19 espécies, cylicostephanus longibursatus, cylicostephanus goldi, cylicocyclus nassatus, cyathostomum tetracanthum, cylicocyclus insigne, cylicostephanus calicatus, coronocyclus labratus, posteriostmum imparidentatum, cyathostomum pateratum, cylicocyclus leptostomus, cylicocyclus radiatus, coronocyclus coronatus, cylicostephanus bidentatus,cylicocyclus ultrajectinus, cylicostephanus minutus, posteriostomum ratzii, cylicostephanus asymetricus, parapoteriostomum euproctus, cylicodontophorus bicoronatus em ordem decrescente de prevalencia. As espécies que apresentaram maior prevalencia foram C. longibursatus, C. goldi, C. nassatus, C. tetracanthum e C. insigne com 100 por cente. Cinco espécimes pertenceram a subfamilia strongylinae, estes estiveram distribuídos em duas espécies, triodontophorus tenuicollis e craterostomum acudicaudatum

Prevalencia, intensidade media e densidade relativa dos ciatostomineos (cyathostominae strongylidae) do colon dorsal de equinos / Prevalence, mean intensity and relative density of cyathostominae (nematoda-strongylidae) of the dorsal colon of equines

Foram identificados, a nivel generico, 834 nematoide em amostras correspondendo 10 por ciento do conteudo do colon dorsal de 10 equinos naturalmente infectados provenientes do Estado do Rio de Janeiro. Foram identificados os generos Cylicostephanus, Cylicodontophorus, Cylicocyclus, Cyathostomum e Gyalocephalus. A maior prevalencia encontrada foi para o genero Cylicostephanus (90 por ciento) e a menor para o Gyalocephalus (10 por ciento). Para o genero Cylicostephanus a intensidade media foi de 53 5 e densidadei relativa foi de 48,2 e para o genero Gyalocephalus, a densidade relativa foi de 6,0 e a intensidade media foi de 0,6