A Rapid Method for Producing Highly Purified Cryptosporidium parvum Oocysts

Investigation of the prophylactic and therapeutic effectiveness of oral thyme extract in rats experimentally infected with cryptosporidium parvum

In this study, the prophylactic and therapeutic activities of thyme extract at different concentrations against experimental Cryptosporidium parvum infection in immunosuppressed rats were investigated. Thyme extract was prepared at four different concentrations (10%, 30%, 50%, and 100%) and administered as a single oral dose of 1 mL for evaluation of its prophylactic efficacy. Five consecutive days after infection was detected in all rats, therapeutic evaluations were also performed. According to the results obtained by daily counting of oocysts in stools, the prophylactic and therapeutic effects of thyme extract administration were significant in comparison to the control group (P˂0.01). Oocyst shedding continued in the control group at high numbers from the beginning to the end of the study, while oocyst counts in the prophylaxis groups remained low throughout the study. On the other hand, oocyst excretion rates were high in the therapeutic groups and decreased rapidly after thyme extract administration. At the end of the study, oocyst excretion had completely stopped for some rats administered thyme extract. There was no group in which oocyst shedding ceased for all rats. No significant differences were observed in the therapeutic or prophylaxis groups regarding the doses administered (P > 0.01). Renal and hepatic functions were monitored by measuring urea, creatinine, alanine transaminase, and aspartate transaminase levels ​​before and after thyme extract administration. As a result, it was concluded that oral thyme extract administration at the doses applied in this study is effective and safe in the prophylactic and therapeutic treatment of experimental cryptosporidiosis in rats.

Newly identified Cryptosporidium parvum virus-1 from newborn calf diarrhoea in Turkey

Cryptosporidium is a common enteric parasite that primarily affects those immunocompromised susceptible individuals and newborns. Detailed investigations have revealed that Cryptosporidium (C.) oocysts contain dsRNA segments which are recently classified under the Partitiviridae family. The relationship between parasite and virus whether or not affect the clinical outcomes of newborn calf diarrhoea is not apparent. The aim of this study was the identification and characterization of Cryptosporidium parvum virus-1 (CSpV1) from newborn calves. We also aimed to understand that parasite-virus symbiont relationship role in the severity of disease cases. Parasitic screening was performed with the help of morphological examinations, immunoassay and molecular polymerase chain reaction (PCR) methods. To further identification of C. parvum oocysts, confocal laser, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) image analysis were used for the morphological investigations. Software-based in silico comparison and identity analyses were conducted from the CSpV1 genome for the genomic sequence characterizations. Cryptosporidium prevalence was 56.2% in newborn calf diarrhoeal cases. Virus dsRNA segments isolated from purified and clarified oocysts. Sequence results showed that we have successfully isolated CSpV1 from C. parvum oocysts. Virus RNA-dependent RNA polymerase (RdRp) was found to be highly variable and showed a species-specific relationship with their carriers. We also identified that CSpV1 frequency was around 8.8% from diarrhoea-showing newborn calves. Cryptosporidium was strongly associated with diarrhoea at early ages of newborns, but the parasite and CSpV1 relationship is not associated with the severity of newborn calf diarrhoea. The current study provides the first report and molecular characterization of CSpV1 in Turkey.

Application of recombinant Cryptosporidium parvum P23 for isolation and prevention

Cryptosporidium parvum is a coccidian protozoan that causes diarrhea in immunocompromised humans and newborn animals. Billions of oocysts of C. parvum can be released from the infected calves and can contaminate the environment. The severity of the disease depends on the immunological status of the individual. Oocysts of Cryptosporidium are extremely resistant to many environmental stresses, and no effective disinfectant and curative agent against this organism is available. In our study, recombinant C. parvum P23 was prepared for application in the isolation and prevention of cryptosporidiosis. P23 is a glycoprotein that belongs to a family of protein of 23-27 kDa and is believed to be expressed in the different life stages of the parasite. Immunostaining analysis using the indirect fluorescent antibody test showed that P23 could be recognized on the surface of the oocysts. The antibody prepared in rabbit against P23 was bound to Sepharose 4B and used for the isolation of oocysts. The results showed that the prepared column was able to bind specifically only the oocysts. The effect of specific recombinant C. parvum IgY antibody against infection with C. parvum was examined in a mouse model. For this aim, purified egg yolk antibody prepared from immunized hens was used to analyze the protective effect of recombinant P23 specific antibody in immunosuppressed adult mice. The results showed more than 70% reduction in oocyst shedding after challenge with 1 × 10(4) oocysts. These results support previous studies of other investigators regarding the protective effect of P23 as an antigen against C. parvum infection and showed that it could be possible to design a passive immunization strategy against C. parvum based on the anti-P23 yolk antibody in animals and immunosuppressed humans.

A new set of primers directed to 18S rRNA gene for molecular identification of Cryptosporidium spp. and their performance in the detection and differentiation of oocysts shed by synanthropic rodents

Cryptosporidium spp. are cosmopolitan protozoa that infect fishes, reptiles, amphibians, birds and mammals. More than 20 species are recognized within this genus. Rodents are a group of abundant and ubiquitous organisms that have been considered reservoirs of Cryptosporidium for humans and livestock. The aim of this study was to design specific primers for the gene encoding 18S rRNA, potentially capable of amplifying any species or genotype of Cryptosporidium spp. and evaluate the diagnostic attributes of the nested-PCR based on such probes. The primers were designed to amplify the shortest segment as possible to maximize the sensitivity of the test, but preserving the discriminatory potential of the amplified sequences for phylogenetic inferences. The nested-PCR standardized in this study (nPCR-SH) was compared in terms of sensitivity with another similar assay (nPCR-XIAO) that has been largely used for the detection and identification of Cryptosporidium spp. worldwide. We also aimed to molecularly characterize samples of Cryptosporidum spp. isolated from synanthropic rodents using these probes. Forty-five rodents were captured in urban areas of the municipality of Umuarama, Paraná State, Brazil. Fecal samples were submitted to three molecular tests (nested-PCRs), two of them targeted to the 18S rDNA gene (nPCR-SH and nPCR-XIAO) and the third targeted to the gene encoding actin (nPCR-actin). The nPCR-SH was tested positive on samples of Cryptosporidum parvum, Cryptosporidum andersoni, Cryptosporidum meleagridis, Cryptosporidum hominis, Cryptosporidum canis, and Cryptosporidum serpentis. Sixteen samples of rodents were positive by nPCR-SH, six by nPCR-XIAO and five by nPCR-actin. Sequencing of amplified fragments allowed the identification of Cryptosporidum muris in three samples of Rattus rattus, and two genotypes of Cryptosporidium, the genotypes mouse II and III. Cryptosporidium genotype mouse II was found in one sample of Mus musculus and genotype mouse III, in twelve samples, being five from R. rattus and seven from M. musculus. The results of this study demonstrated that the primers designed for detection of Cryptosporidium spp. were more efficient than those used in the nPCR-XIAO. Genotypes or species of Cryptosporidium that can be usually transmitted for human beings and livestock were not found in synanthropic rodents, suggesting that the importance of these animals in zoonotic transmission of cryptosporidiosis should be revisited.

Fecundity of Cryptosporidium parvum is correlated with intracellular levels of the viral symbiont CPV

Differences in the virulence and fecundity of Cryptosporidium parvum isolates have been observed by several researchers studying cryptosporidiosis. The purpose of the present study was to determine if there was a correlation between intracellular levels of the viral symbiont CPV in C. parvum and fecundity of two isolates of the parasite, namely C. parvum Beltsville (B) and C. parvum Iowa (I). Dairy calves infected with 10(6)C. parvum-B excreted 5-fold more oocysts compared with calves infected with the same number of C. parvum-I oocysts. The increased fecundity of the former strain was corroborated by semi-quantitative PCR assay of DNA isolated from cell cultures infected with either C. parvum-B or C. parvum-I. Quantitative reverse transcriptase-PCR analysis of viral RNA revealed a 3-fold greater number of CPV in C. parvum-B compared with C. parvum-I oocysts. These findings may indicate a role for CPV in fecundity and possibly virulence of C. parvum.