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Infektivita sporozoitů kryptosporidií s ohledem na lokalizaci vývojového cyklu
SKLENÁŘOVÁ, Eliška
Cryptosporidium, belonging to the phylum Apicomplexa, are parasites found across all classes of vertebrates worldwide, including humans. They infect the gastrointes-tinal tract, leading to acute or chronic diarrheal disease, especially in individuals with weakened immune systems. Infection spreads through contaminated water, food, or direct contact. A main aspect is the excystation process, which allows the parasites to infect the host. The study focuses on the environmental conditions of the gastrointestinal tract where Cryptosporidium excystation occurs and the factors ne-cessary for this process. Research has shown that different species of Cryptosporidi-um exhibit variability in excystation depending on their location in the host's body. The results suggest that different species of Cryptosporidium excyst most efficiently in different parts of the digestive tract, thus proper excystation localization is crucial for successful infection. Experiments have shown that environmental temperature and pH play a key role. Research indicates the existence of a protective factor in the host's body that limits excystation in the digestive tract. The study also examines the prepatent period of individual Cryptosporidium species and finds that the method of inoculation does not affect the length of this period. Understanding the excystation process and the conditions that influence it is crucial for the development of effecti-ve cryptosporidiosis therapy.
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Kuřecí embrya jako inkubátor pro pomnožení parazitů rodu Cryptosporidium
SCHULZOVÁ, Tereza
This study aimed to determine the extent to which infection at the embryo stage can enhance the propagation of Cryptosporidium oocysts in chickens. Nine-day-old chicken embryos and one-day-old chickens were experimentally infected with different doses of Cryptosporidium baileyi and Cryptosporidium parvum oocysts. Post hatching, all chickens had demonstrable infections, and the infection dose had no effect on the course of infection. Chickens infected as embryos shed oocysts immediately after hatching and, over the course of the infection, they shed significantly more oocysts than infected oneday-old chickens. In chickens infected as embryos, C. baileyi was found in all organs except the brain, with highest infections in the trachea and oesophagus, and C. parvum was found only in the gastrointestinal tract and trachea, with highest infections in the gut and cloaca. In one-day-old infected chickens, C. baileyi was found only in the gastrointestinal tract and trachea, with highest infections in the gut. Chickens infected as embryos with C. baileyi died within 16 days of hatching. All other chickens cleared the infection within 13-25 days. Based on these findings, infection of chicken embryos could serve as a cost effective and simple model for the propagation of Cryptosporidium spp.
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Laparotomické infekce hostitelů střevními a žaludečními kryptosporidiemi
HAVRDOVÁ, Nikola
Cryptosporidium are protozoan parasites that infect the gastrointestinal epithelium of various vertebrate hosts. The genus has two major phylogenetic groups: a gastric group that infect the epithelium of the stomach and an intestinal group that infect the epithelium of the small and large intestine. Cryptosporidium are transmitted by the faecal-oral route and infect epithelial cells following excystation of the environmental oocyst stage. It has been proposed that excystation of intestinal species is triggered by exposure to the acidic stomach contents, although this has not been verified experimentally. This study aimed to determine whether exposure to stomach contents is necessary for in vivo infection by the intestinal species C. parvum and whether passage through the intestine is necessary for the gastric species C. proliferans to cause infection. It was shown that purified and non-purified oocysts of C. parvum were infectious for SCID mice following surgical inoculation directly into different parts of the small intestine, demonstrating that passage through the stomach is not necessary for infection by this intestinal species. Inoculation of the jejunum resulted in a course of infection similar to oral inoculation. Cryptosporidium proliferans was infectious for na?ve SCID mice following surgical extraction from the stomach of infected SCID mice, demonstrating that passage through the small intestine is not necessary for infection by this gastric species. However, surgical inoculation of C. proliferans oocysts directly into the intestinum tenue did not cause infection.
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The role of rotifers by filtration of \kur{Cryptosporidium} in water column
BRŮČKOVÁ, Petra
Filtration abilities of Cryptosporidium parvum oocysts by rotifers (Brachionus calyciflorus) were studied. The filtration rate of rotifers is quick: the passage of oocysts through the digestive system is few minutes only. During the first 10 minutes 24300 of whole amount one million oocysts passed through the digestive system of 100 rotifers. Moreover, 93% of oocysts were death after passage. All oocysts expelled were unable to infect suckling BALB/c mice. Oocysts were degraded in mastax, stomach and intestine. Rotifers can be use for detection of cryptosporidia oocysts in water and they effectively decrease their numbers.
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