Experimental Cryptosporidiosis in a Primate Model

Abstract

Cryptosporidium causes a disease in infant macaques that is clinically, histologically, and microbiologically indistinguishable from that seen in young children. A reproducible experimental model of cryptosporidiosis has been developed in pigtailed macaques (Macaca nemestrina) and used to studied the infectious dose of oocysts and the effect of inoculum size on severity of disease. Inoculation with either 2 x 10(5) or 10 oocysts via nasogastric tube resulted in clinical enteritis and the fecal passage of large numbers of cryptosporidial oocysts in all four primates studied. The size of the inoculum had no apparent effect on the severity or duration of disease. Rechallenge 2 weeks after resolution of the primary infection demonstrated partial acquired immunity. The small inoculum size coupled with the passage of large numbers of oocysts contributes to the highly contagious nature of cryptosporidiosis among captive primates and may be relevant to the epidemiology and control of cryptosporidiosis in humans.

Occurrence ofGiardiasp. cysts andCryptosporidiumsp. oocysts in faeces from public parks in the west of Scotland

“…Whereas the minimum infectious dose of Giardia for man is 10-100 cysts [12], the minimum infectious dose of Cryptosporidium for man is unknown. However, as few as 10 oocysts can produce infection in non-human juvenile primates [13].…”

Development and application of a quantitative, specific assay for Cryptosporidium parvum oocyst detection in high-turbidity environmental water samples.

“…Cryptosporidium oocysts are resistant to routine water treatments and chemical disinfectants, 8 and low numbers of viable oocysts can cause infection. [9][10][11] The EPA developed a comprehensive nationwide monitoring program termed the Information Collection Rule (ICR) in 1996, 12 which requires routine monitoring for these protozoa, other infectious agents, and contaminants. The current method endorsed by the American Society for Testing and Materials (ASTM) for detecting Cryptosporidium oocysts in water supplies is laborintensive and time-consuming.…”

Severe giardiasis and cryptosporidiosis in Scotland, UK

“…However, both infections may also be asymptomatic or characterized by only mild signs and symptoms. Both infections have a relatively low infective dose [1][2][3]. Although direct faecal-oral transmission is probably the more common transmission route, large outbreaks of waterborne giardiasis and cryptosporidiosis have been documented [e.g.…”