Molecular Identification of Cryptosporidium Species from Pet Snakes in Thailand

Cryptosporidium is an important pathogen causing gastrointestinal disease in snakes and is distributed worldwide. The main objectives of this study were to detect and identify Cryptosporidium species in captive snakes from exotic pet shops and snake farms in Thailand. In total, 165 fecal samples were examined from 8 snake species, boa constrictor (Boa constrictor constrictor), corn snake (Elaphe guttata), ball python (Python regius), milk snake (Lampropeltis triangulum), king snake (Lampropeltis getula), rock python (Python sebae), rainbow boa (Epicrates cenchria), and carpet python (Morelia spilota). Cryptosporidium oocysts were examined using the dimethyl sulfoxide (DMSO)-modified acid-fast staining and a molecular method based on nested-PCR, PCR-RFLP analysis, and sequencing amplification of the SSU rRNA gene. DMSO-modified acid-fast staining revealed the presence of Cryptosporidium oocysts in 12 out of 165 (7.3%) samples, whereas PCR produced positive results in 40 (24.2%) samples. Molecular characterization indicated the presence of Cryptosporidium parvum (mouse genotype) as the most common species in 24 samples (60%) from 5 species of snake followed by Cryptosporidium serpentis in 9 samples (22.5%) from 2 species of snake and Cryptosporidium muris in 3 samples (7.5%) from P. regius.

Comparison of Resistance to gamma-Irradiation between Cryptosporidium parvum and Cryptosporidium muris Using In Vivo Infection

In the genus Cryptosporidium, there are more than 14 species with different sizes and habitats, as well as different hosts. Among these, C. parvum and C. hominis are known to be human pathogens. As C. parvum can survive exposure to harsh environmental conditions, including various disinfectants or high doses of radiation, it is considered to be an important environmental pathogen that may be a threat to human health. However, the resistance of other Cryptosporidium species to various environmental conditions is unknown. In this study, resistance against gamma-irradiation was compared between C. parvum and C. muris using in vivo infection in mice. The capability of C. muris to infect mice could be eliminated with 1,000 Gy of gamma-irradiation, while C. parvum remained infective in mice after up to 1,000 Gy of gamma-irradiation, although the peak number of oocysts per gram of feces decreased to 16% that of non-irradiated oocysts. The difference in radioresistance between these 2 Cryptosporidium species should be investigated by further studies.

In vitro culture of Cryptosporidium muris in a human stomach adenocarcinoma cell line

We investigated the optimal culture conditions for Cryptosporidium muris in a human stomach adenocarcinoma (AGS) cell line by determining the effects of medium pH and of selected supplements on the development of C. muris. The optimum pH of the culture medium required for the development of C. muris was determined to be 6.6. The number of parasites significantly increased during cultivation for 72 hr (p < 0.05) at this level. On the other hand, numbers decreased linearly after 24 hr of incubation at pH 7.5. When cultured in different concentrations of serum, C. muris in media containing 5% FBS induced 4-7 times more parasites than in 1% or 10% serum. Of the six medium supplements examined, only 1 mM pyruvate enhanced the number of C. muris in vitro. Transmission electron microscopic observation showed the developmental stages of C. muris in the cytoplasm of the cells, not in an extracytoplasmic location. The growth of C. muris in AGS cells provides a means of investigating its biological characteristics and of testing its response to therapeutic agents. However, a more optimized culture system is needed for the recovery of oocysts on a large scale in vitro.

Measurement of Morphological Parameters of Cryptosporidium murisOocysts by Digital Image Processing Technology / 中国寄生虫学与寄生虫病杂志

Objective To establish and analyze the morphological parameters of the oocysts of Cryptosporidium muris for defining their morphological change. Methods Oocysts were collected from KM mice(immunodepressed by dexamethasone for 10 days) and examined with modified acid-fast staining. Images of 1 190 oocysts were acquired by photograph system. The length, width, perimeter, area and equivalent diameter of the oocysts were obtained by computer digital image processing system and analyzed by SPSS software (Version 11.0). Result The average length of the oocysts was 5.93 ?m, ranging from 3.36 ?m to 8.51 ?m in 95% confidence interval of them. The average width was 4.96 ?m, ranging from 3.26 ?m to 6.66 ?m in 95% confidence interval of them. The average perimeter was 18.03 ?m and the average area was 16.08 ?m2. Conclusion Data obtained from the computer system are objective and precise, offering scientific foundation for measuring the oocysts and for identifying Cryptosporidium spp.[