RESUMO
The symptoms of Anopheles aquasalis larvae naturally infected by a microsporidium, and the ultrastructure of the infecting spores is described. The larvae were maintained under laboratory conditions in salt concentrations of 10 g/l and 20 g/l of water. Daily recordings of the mortality of the larvae were made and the dates of change of instar were noted. Infected larvae were processed for transmission electronic microscopy using conventional methods at pH 7.2 and 260 mOsm/l. The infection by the microsporidia was positively correlated with an increase in the mean duration of the fourth instar of 2.88 to 6.33 days in 10 g/l of salt and of 2.47 to 6.14 days in 20 g/l of salt. Larval mortality also increased by approximately 50% during this instar in both salt concentrations. Development time and survival were not affected during the other immature stages. The mature spores found in the intestines of infected larvae were barrel shaped and measured approximately 2.6 x 2.4 mm. The exospore has a collar shaped prolongation at the posterior end of the spore. The spores are uninuclear with a posterior vacuole. The polar filament is anisofilar with nine rings, five with a diameter of 58 nm each and four with a diameter of 23 nm each. The polarplast is lamellate, and more tightly packed in the apical region. The reduction of the survival of A. aquasalis larvae infected with the microsporidia, and the increase in the development time suggest that this parasite might have a potential as a biological control of this pest. The microsporidium described here has similar characteristics to that of the genus Parathelohania. I suggest that the microsporidium found in A. aquasalis represents a new species and I propose the name Parathelohania aquasalensis. This is the first report of a microsporidium from a dipteran in Venezuela.
Assuntos
Anopheles/parasitologia , Microsporida/ultraestrutura , Esporos de Protozoários/ultraestrutura , Animais , Feminino , Larva/parasitologia , Microscopia Eletrônica , Microsporida/classificação , Análise de Sobrevida , VenezuelaRESUMO
A Encephalitozoon-like microsporidia was found in epithelial cells of the midgut and the salivary glands of Amblyomma cajennense (F.) and Anocentor nitens (Neumann) that had fed on rabbits. Ultrastructural studies demonstrated that all stages of the life cycle of the parasite occur in parasitophorous vacuoles and contain only 1 nucleus. The sporonts detach from the limiting membrane of the vacuole and divide by binary fission to produce the sporoblasts, each presenting a thickened electron-dense wall, and a primordium of a polar filament. Each spore contained a single nucleus, an electron-dense and rough exospore, an electron-lucent and thick endospore, and 5 coils of the polar tubule.
Assuntos
Encephalitozoon/isolamento & purificação , Microsporida/isolamento & purificação , Carrapatos/parasitologia , Animais , Sistema Digestório/parasitologia , Encephalitozoon/classificação , Encephalitozoon/fisiologia , Encephalitozoon/ultraestrutura , Estágios do Ciclo de Vida , Microsporida/classificação , Microsporida/fisiologia , Microsporida/ultraestrutura , Mucosa/parasitologia , Coelhos , Vacúolos/ultraestruturaRESUMO
Microsporidia are protozoa parasites responsible for significant gastrointestinal disease in patients infected with human immunodeficiency virus. We evaluated a PCR assay of stool samples, duodenal aspirates, and biopsy specimens from patients with Enterocytozoon bieneusi infection. A 210-bp DNA fragment of the unique rRNA intergenic spacer could be amplified from all samples infected with E. bieneusi, but no amplification was seen by using DNA purified from samples with Septata intestinalis or other parasites and from negative control human cells. These results suggest that the PCR in stool samples may be a useful tool for the diagnosis of intestinal microsporidiosis in patients with AIDS.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/parasitologia , Gastroenteropatias/complicações , Gastroenteropatias/parasitologia , Microsporida/genética , Microsporida/isolamento & purificação , Microsporidiose/complicações , Microsporidiose/parasitologia , Reação em Cadeia da Polimerase/métodos , Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Animais , Sequência de Bases , Biópsia , Primers do DNA/genética , DNA de Protozoário/genética , DNA de Protozoário/isolamento & purificação , DNA Ribossômico/genética , DNA Ribossômico/isolamento & purificação , Duodeno/parasitologia , Estudos de Avaliação como Assunto , Fezes/parasitologia , Gastroenteropatias/diagnóstico , Humanos , Microscopia Eletrônica , Microsporida/ultraestrutura , Microsporidiose/diagnósticoRESUMO
Protozoa of the order Microsporida have become regarded as causes of several pathologies in patients with severe immunodeficiencies. Apparently they are transmitted to the human through fecalism, but also the respiratory route has been considered. People most affected are young males infected with the human immunodeficiency virus. The most important genera are: Enterocytozoon, Encephalitozoon, Septata, Nosema and Pleistophora. There are discrepancies about the biology of these parasites and little is known of their behavior in the human host. It is concluded that with the advent of AIDS, many nosological entities by opportunistic organisms, that were not previously considered as human infections are appearing. This work is a review of the literature published from 1959 to 1995, related to epidemiological, clinical, diagnostic and therapeutic aspects.