Studies on coccidian oocysts (Apicomplexa: Eucoccidiorida) / Estudos sobre oocistos de coccídios (Apicomplexa: Eucoccidiorida)

The oocysts of the coccidia are robust structures, frequently isolated from the feces or urine of their hosts, which provide resistance to mechanical damage and allow the parasites to survive and remain infective for prolonged periods. The diagnosis of coccidiosis, species description and systematics, are all dependent upon characterization of the oocyst. Therefore, this review aimed to the provide a critical overview of the methodologies, advantages and limitations of the currently available morphological, morphometrical and molecular biology based approaches that may be utilized for characterization of these important structures. It has become apparent that no single methodology is sufficient to fully characterize these structures and the majority of researchers favor the use of combinational or polyphasic approaches.

Os oocistos de coccídios são estruturas robustas, frequentemente isoladas das fezes ou urina de seus hospedeiros, os quais oferecem resistência a danos mecânicos e permitem que os parasitas sobrevivam e permaneçam infecciosos por períodos prolongados. O diagnóstico da coccidiose, descrição das espécies e sistemática são dependentes da caracterização do oocisto. Portanto, esta revisão teve como objetivo fornecer uma visão crítica das metodologias, vantagens e limitações dos métodos morfológicos, morfométricos e moleculares que podem ser utilizados para a caracterização destas estruturas importantes. Tornou-se evidente que nenhuma metodologia única é suficiente para caracterizar completamente essas estruturas e que a maioria das pesquisas favorecem o uso de metodologias combinadas ou polifásicas.

Fecal and Molecular Survey of Neospora caninum in Farm and Household Dogs in Mashhad Area, Khorasan Province, Iran

Neospora caninum is an important cause of abortion in dairy cattle worldwide. Dog is the definitive host for N. caninum and can infect dairy cattle. The aim of this study is to determine the prevalence of Neospora oocysts in feces of dogs from dairy farms. A total of 174 fecal samples was collected from 89 farm dogs and 85 household dogs during 2006 and 2008. Fecal samples of dogs were microscopically examined for detecting Hammondia Neospora-like oocysts (HNLO) by Mini Parasep(R)SF fecal parasite concentrator. HNLO were microscopically detected in 4 fecal samples (2.2%). The fecal samples with HNLO were examined by N. caninum-specific PCR. Two of the samples were positive for N. caninum. The 2 positive fecal samples were selected for inoculation to calves. Two inoculated calves were seronegative by ELISA for 4 months post-infection. This is the first report of finding N. caninum DNA in feces of farm dogs in Mashhad area, Iran.

Aflatoxin effetc on the oocysts morphometry and contribution on the morphology of Eimeria bateri Bhatia, Pandey and Pande, 1965 from the japanese quail Coturnix japonica in Brazil / Efeito da aflatoxina sobre a morfbmetria dos oocistos e contribuição para a morfologia de Eimeria bateri Bhatia, Pandey and Pande, 1965 da Codorna japonesa Coturnix japonica no Brasil

The purpose of this study was to characterize Eimeria bateri oocysts and to evaluate the aflatoxin effect in the morphometry of sporulated oocysts in Japanese quails infected naturally. Of a total of 50 quails naturally infected by E. bateri were randomly divided into two groups with 25 birds each. In one of them, quails were orally administered with aflatoxin in dose of 0.04 mg/kg body weight previously. Both experimental groups shed E. bateri oocysts. These oocysts were subspherical to ellipsoidal, 25.1 x 18.9 Lim, with bi-layered wall. Micropyle and residuum were absent, but one or more polar granules were present. Sporocysts elongate ovoid, 12.5 x 7.4 μm. Stieda and substieda bodies were present. Sporocyst residuum was dispersed and sporozoites presented a nucleus and a refractile body. Histograms confirmed the presence of a single species, E. bateri. Linear regression proved that E. bateri oocysts are polymorphic, due, basically, to shape of these oocysts. The comparative morphometry between two experimental groups demonstrated that the aflatoxin influenced significantly in the E. bateri oocysts.

O objetivo deste estudo foi caracterizar os oocistos de Eimeria bateri e avaliar o efeito da aflatoxina na morfometria destes oocistos em codornas japonesas naturalmente infectadas. Cinqüenta codornas naturalmente parasitadas por E. bateri foram separadas aleatoriamente em dois grupos com 25 aves cada. Um dos grupos foi intoxicado experimentalmente com aflatoxina, por via oral, na dose de 0,04 mg/kg de peso vivo. Os dois grupos experimentais eliminaram oocistos de E. bateri nas fezes. Esses oocistos foram de subesféricos a elipsóides, 25,1 x 18,9 Lm, com parede dupla. A micrópila e o resíduo estavam ausentes, mas um ou vários grânulos polares estavam presentes. Esporocistos ovóides alongados, 12,5 x 7,4 L m. Os corpos de Stieda e substieda estavam presentes. O resíduo do esporocisto estava disperso e os esporozoítas apresentaram um núcleo e um corpo refráctil. Os histogramas confirmaram a presença de uma única espécie, E. bateri. A regressão linear comprovou que os oocistos de E. bateri são polimórficos, devido, basicamente, à forma desses oocistos. A morfometria comparativa entre os dois grupos experimentais, demonstrou que a aflatoxina influiu significativamente nos oocistos de E. bateri.

Molecular characterisation of Cryptosporidium: an emerging parasite.

PURPOSE: The aim of the present study was to determine the prevalence of Crytposporidium in local population and to understand its epidemiology by molecular methods. METHODS: Faecal samples from 681 children and 804 adults, admitted to tertiary care hospitals in twin cities of Hyderabad and Secunderabad with complaints of diarrhoea; and six calves with diarrhoea, were screened for Cryptosporidium oocysts by microscopy and enzyme linked immunosorbent assay (ELISA). Polymerase chain reaction restriction fragment length polymorphism (PCR RFLP) based identification of Cryptosporidium species in positive specimens was done to elucidate epidemiology of Cryptosporidium. RESULTS: Cryptosporidium was found in 52 (7.6%) children and 7(0.9%) adults and 1(16.6%) calf with diarrhoea. The prevalence of Cryptosporidium in children below five years of age was 8.2% and 14.3% in children in the age group of six months to one year. Of the 42 samples genotyped 29 (69%) were C. hominis and 8 (19%) were C. parvum and 5 (11.9%) were mixed infection with the two species. CONCLUSIONS: Children in the age group of six months to one year were found to be the most vulnerable. The occurrence of C. parvum, in nearly one third of cases in the present series indicates that the zoonotic transmission is of considerable significance in the epidemiology of Cryptosporidiosis in the study area.