Cryptosporidium hominis
From IDWiki
- A member of the Cryptosporidium species which causes diarrheal disease in humans
- Similar to Cryptosporidium parvum which typically infects cows, but can also infect humans
Microbiology
- Protozoan parasite in the genus Cryptosporidium
Epidemiology
- Infects humans, but can also infect cows, mice, gnotobiotic pigs, and rarely other species
- Transmitted fecal-oral via environmental contamination (such as recreational water), and can be spread person-to-person
- Outbreaks are most commonly associated with drinking water, even when properly treated
- Resistant to chlorination and can survive in the environment up to 6 months
- Causes 2-6% of traveller's diarrhea
Life Cycle
- Host ingests an oocyst (needing as few as 10 to cause disease)
- The oocyst excyst in the stomach and proximal small bowel, releasing four sporozoites
- Sporozoites bind to the intestinal epithelial cells and becomes vacuolized by the host cell membrane
- In the parasitophorous vacuole, they reproduce asexually into further sporozoites, which divide into type I meronts
- The type I meronts mature and release motile merozoites
- The merozoites again attach to the intestinal epithelial cells
- Merozoites then either reproduce asexually, as above, or sexually
- Sexual reproduction involves a macrogamont and microgamont, which form a zygote
- The zygote develops into an oocyst which contains four sporozoites
- Oocysts may be involved in auto-inoculation (if thin-walled) or environmental contamination (if thick-walled)
