Phylogenetic analyses of Chilomastix and Retortamonas species using in vitro excysted flagellates.

In vitro excystation of cysts of microscopically identified Chilomastix mesnili and Retortamonas sp. isolated from Japanese macaques and Retortamonas sp. isolated from small Indian mongooses could be induced using an established protocol for Giardia intestinalis and subsequently by culturing with H2S-rich Robinson's medium supplemented with Desulfovibrio desulfuricans. Excystation usually began 2 h after incubation in Robinson's medium. DNA was isolated from excysted flagellates after 4 h of incubation or from cultured excysted flagellates. Phylogenetic analysis based on their 18S rRNA genes revealed that two isolates of C. mesnili from Japanese macaques belonged to the same cluster as a C. mesnili isolate from humans, whereas a mammalian Retortamonas sp. isolate from a small Indian mongoose belonged to the same cluster as that of an amphibian Retortamonas spp. isolate from a 'poison arrow frog' [sequence identity to AF439347 (94.9%)]. These results suggest that the sequence homology of the 18S rRNA gene of the two C. mesnili isolates from Japanese macaques was similar to that of humans, in addition to the morphological similarity, and Retortamonas sp. infection of the amphibian type in the small Indian mongoose highlighted the possibility of the effect of host feeding habitats.

Involvement of ICOS-B7RP-1 costimulatory pathway in the regulation of immune responses to Leishmania major and Nippostrongylus brasiliensis infections.

The ICOS-B7RP-1-mediated T cell costimulatory pathway has been implicated crucial for T cell activation and differentiation. In this study, we investigated the role of this costimulation in the regulation of immune responses to parasitic infections by using blocking antibody against B7RP-1 as well as ICOS-deficient mice. The administration of anti-B7RP-1 monoclonal antibody (mAb) significantly suppressed the footpad swelling in susceptible BALB/c mice upon Leishmania major infection. The observation was consistent not only with the significant suppression of IL-4, IL-5 and IL-10 secretion from lymph node cells, which were derived from L. major-infected mice, but also with the significant reduction of total serum IgE and IgG(1) in anti-B7RP-1 mAb-treated BALB/c mice. Infection of ICOS-deficient mice with L. major also suggested the impaired Th2 immune responses in the absence of this costimulation. The immunological function of ICOS-B7RP-1 costimulatory pathway in infection was further confirmed by infecting anti-B7RP-1 mAb-treated wild type or ICOS-deficient mice with Nippostrongylus brasiliensis. The characteristic elevation of total serum IgE and eosinophilia upon N. brasiliensis infection was suppressed by blocking this costimulation. Moreover, the protection to N. brasiliensis adult worms was suppressed in anti-B7RP-1 mAb-treated wild type or ICOS-deficient mice. These results suggest the crucial role of this costimulatory pathway in the regulation of Th2-biased T cell differentiation and in host immune responses against L. major and N. brasiliensis infections.

Ausência de amebíase invasiva em aidéticos homossexuais masculinos, no Recife / Absence of invasive amoebiasis in male homosexual AIDS patients in Recife

The purpose of this paper was to determine if among male homosexual AIDS [correction of SIDA] patients, the Entamoeba histolytica was able to product invasive illness. From the 77 investigated patients only one (1.3 per cent) has cysts of E. histolytica in his stools. The electrophoresis of the only isolated strain has shown it was from zimodeme I, non pathogenic. The research of antiamebic antibodies was negative in the serum of the totality of patients. Those results showed that even in immunocompromised patients with AIDS [correction of SIDA], E. histolytica strain found in Recife was not able to produce disease. The utilization of metronidazol is not indicated in amoebic cysts carriers.

Prevalence and pathogenicity of Entamoeba histolytica in three different regions of Pernambuco, Northeast Brazil (1)

Exames parasitologicos foram realizados em amostras fecais de 663 residindo em cidades de Pernambuco, Nordeste brasileiro: Recife, Palmares e Bodoco. A populacao de Bodoco, situada na regiao do semi-arido de Pernambuco, foi investigada para amebiase e comparada com a do Recife, cidade metropolitana com cerca de 1,3 milhoes de habitantes, e com outra da zona de plantacao de cana-de-acucar do estado, Palmares. Nao foi observada evidencia da presenca de cepas invasivas de E. histolytica nesses habitantes desde que aquelas isoladas das amostras fecais, com zimodomas dos tipos I, III, IV, VIII, IX, X, XVII e XVIII, sao reconhecidas como nao patogenicas. Ademais, a prevalencia de helmintos intestinais e de infeccoes por protozoarios mostrou que esses individuos sao infectados por outros agentes responsaveis por quadros diarreicos.

Parasitological and serological studies on amoebiasis and other intestinal parasitic infections in Recife and its suburban area, northeast Brazil

Exames parasitológicos foram realizados em 187 pacientes do Hospital do IMIP e 464 habitantes de vários vilarejos no município do Cabo, 50 Km à sudeste de Recife, durante os meses de abril a agosto. Aproximadamente 71% dos pacientes examinados do IMIP e 92% dos examinados do Cabo apresentavam-se infectados com, no mínimo, uma espécie de parasita intestinal. Houve uma diferença mínima na taxa de prevalência de trichiura entre as duas áreas, entretanto a prevalência de Ascaris lumbricoides, família Ancylostomidae, Strongyloides stercoralis, Schistosoma mansoni e Entamoeba histolytica foi maior entre os habitantes do Cabo. Somente a Giardia lamblia apresentou uma taxa de prevalência maior nos pacientes do IMIP. O cultivo em tubo de ensaio revelou que a prevalência do Necator americanus em relaçäo a do Ancylostoma duodenale era muito maior em ambas as áreas e que a do S. stercoralis entre os pacientes do IMIP e dos habitantes do Cabo era, respectivamente, 4.5% e 9.6%. A amebíase foi verificada através de exames sorológicos, imunodifusäo em gel (GDP) e enzima imunoensaio (ELISA), usando como antígeno extrato bruto preparado a partir dos trofozoitos de E. histolytica (cepa HM-1: IMSS), realizados em 615 soros, onde nenhuma reaçäo positiva aparente foi observada através da imunodifusäo, contudo foram observados resultados positivos em 32 dos 615 casos através da enzima imunoensaio