ATTEMPTS TO ESTABLISH EXPERIMENTALCYCLOSPORA CAYETANENSISINFECTION 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.

Identification and morphologic and molecular characterization of Cyclospora macacae n. sp. from rhesus monkeys in China

“…C. cayetanensis is known to be human pathogenic, and humans are probably the only natural host (Aksoy et al 2014; Ortega and Sanchez 2010). Attempts have been made to identify nonhuman hosts or reservoirs for C. cayetanensis and to establish experimental infection model in multiple laboratory animals (also including rhesus monkeys), but none of the tested animals became infected (Eberhard et al 1999b; Eberhard et al 2000). However, results of this and a previous study have identified the presence of C. cayetanensis in the fecal samples of two rhesus monkeys in China and Nepal, suggesting that C. cayetanensis may under rare occasions infect rhesus monkeys (Chu et al 2004).…”

Advances in Cyclosporiasis Diagnosis and Therapeutic Intervention

“…There have been attempts to characterize human serological immune responses to cyclosporiasis, involving specific IgG and IgM antibodies being tested via enzyme-linked immunosorbent assays (Wang et al, 2002), but specific diagnosis of infection at the individual patient level has not been achieved (Giangaspero and Gasser, 2019). The main constrain is the unavailability of suitable Cyclospora culture method that can be used for the propagation of oocysts and also the in-depth study of various aspects of the parasite (Eberhard et al, 2000;Cinar et al, 2015).…”

“…Oocyst sporulation and infectivity testing in animal model is an ideal method for evaluating the viability and infectivity of the oocysts (Giangaspero and Gasser, 2019). However, due to the unavailability of effective in vitro culture methods and in vivo animal models for C. cayetanensis, sporulation in 2.5% potassium dichromate is currently regarded as the only indicator for oocyst viability (Eberhard et al, 2000).…”

Infections by Intestinal Coccidia and Giardia duodenalis

“…Attempts to infect other animal species have proved unsuccessful 63 ; thus, there is no animal model to better understand its biology. The live stages of Cyclospora were described from jejunal biopsies.…”