Attempts to Establish Experimental Cyclospora cayetanensis Infection in Laboratory Animals

Abstract

Attempts were made to develop an animal model for Cyclospora cayetanensis to identify a practical laboratory host for studying human cyclosporiasis. Oocysts collected from stool of infected humans in the United States, Haiti, Guatemala, Peru, and Nepal were held in potassium dichromate solution to allow development of sporozoites. The following animal types were inoculated: 9 strains of mice, including adult and neonatal immunocompetent and immune-deficient inbred and outbred strains, rats, sandrats, chickens, ducks, rabbits, jirds, hamsters, ferrets, pigs, dogs, owl monkeys, rhesus monkeys, and cynomolgus monkeys. Most animals were inoculated by gavage, although some of the primates were fed oocysts on food items. The animals were examined for signs of infection, particularly diarrhea, and stool samples were examined for 4-6 wk after inoculation. None of the animals developed patent infections or signs of infection. We conclude that none of the animals tested is susceptible to infection with C. cayetanensis.

Cyclospora cayetanensis

“…In contrast to these findings, the parasite was not detected in Haiti from 327 domestic animals, including pigeons, chickens, ducks, turkeys, guinea pigs, cats, dogs, goats, pigs, horses, and cattle (Eberhard et al, 1999c) and in Brazil from 140 stray dogs (Carollo et al, 2001), and Lima, Peru (Ortega et al, 1997b). Attempts toinfect several animals with C. cayetanensis have been unsuccessful, suggesting host specificity (Eberhard et al, 2000). Although C. cayetanensis was reported to be propagated in albino mice (Sadaka et al, 2001) and guinea pigs (Wang et al, 2002) the findings could not be confirmed (Ortega et al, 2010).…”

Update on Cyclospora cayetanensis , a Food-Borne and Waterborne Parasite

“…Cyclospora oocysts have been found in feces of chickens (37,62,70), ducks (62,197), and dogs (27,37,62,194) collected in countries where Cyclospora is endemic (27,62,63). However, attempts to experimentally infect a variety of animals (63) and humans (5) have been unsuccessful. The presence of Cyclospora in stools from animals could be explained by eating or coprophagic habits of the surveyed animals.…”

“…Other studies surveying feces of cattle, horses, pigs, goats, dogs, cats, guinea pigs, turkeys, chickens, ducks, and pigeons did not find Cyclospora in these animal species (27,62,141). Attempts to infect different animals (chickens, ducks, mice, gerbils, hamsters, rabbits, rats, sand rats, ferrets, pigs, dogs, monkeys, and baboons) with C. cayetanensis have been unsuccessful, suggesting host specificity (63). More recently, Chu et al (37) identified C. cayetanensis in domestic animals by PCR, but whether these findings represent true or spurious infections remains to be clarified.…”

“…The extended period for oocysts to sporulate and become infectious raises questions as to where and how sporulation occurs. Unsuccessful attempts to infect animals or cells with sporulated oocysts suggest the need for a specific, unknown trigger to initiate infection (63).…”

Wide genetic variations at 18S ribosomal RNA locus of Cyclospora cayetanensis isolated from Egyptian patients using high resolution melting curve

“…This finding may support the role of animals as transport or reservoir hosts (zoonotic transmission). Although attempts to establish an experimental infection in laboratory animals have been unsuccessful thus far (Eberhard et al 2000) in an endemic area of Nepal, oocysts suspected to be those of C. cayetanensis were found in the feces of chickens and ducks, respectively (Garcia-Lopez et al 1996;Sherchand et al 1999). On the same line, human cyclosporiasis was most frequently associated with the ownership of domestic animals (Zepra et al 1995;Bern et al 1996).…”