[Experimental infection of the gerbil (Meriones unguiculatus) by Colombian isolates of Giardia duodenalis].
BACKGROUND
Natural and experimental Giardia infections have been reported from bovines, equines, goats, canines, felines and rodents such as mice, rats and gerbils. The latter have provided successful animal models for Giardia duodenalis and Giardia muris experimental infections.


OBJECTIVE
The gerbil model was used to establish the pattern of infection of Colombian Giardia human isolates.


METHODS
Giardia cysts were obtained from stool specimens of symptomatic giardiasis patients by means of sucrose-percoll gradients. Animal inoculation was performed by gastric intubation and injection with 5 x 10(3) Giardia cysts. The course of infection was established by counting cysts every day and trophozoites weekly throughout a period of 30 days.


RESULTS
The pattern of cyst excretion was found to be intermittent. Cysts were released during the second and third weeks of infection but not during the first or fourth weeks. The mean minimal number of cysts released per 2-hr collection period was 79 and the mean maximum number was 17,943. Colonization of the small intestine by trophozoites was observed with a mean number ranging from 15,000 to 6,577,778 trophozoites/ml.


CONCLUSIONS
Gerbils inoculated with G. duodenalis isolates obtained from geographical areas outside Colombia resolved the infection between 86 and 114 days after infection, whereas gerbils infected with Colombian G. duodenalis isolates resolved the infection at 30 days. The gerbil proved to be a good animal model for experimental infection with Colombian isolates of G. duodenalis. Experimental Giardia infection of gerbils permit a sufficient yield of cysts and trophozoites to be used as antigens for the immunization of other animals and to obtain Giardia antibodies that could be used for Giardia antigen detection assays in stool specimens.
Arévalo
Adriana
A
Grupo de Parasitología, Instituto Nacional de Salud, Bogota, D. C., Colombia. aarevalo@ins.gov.co
Duque
Sofía
S
Nicholls
Rubén Santiago
RS
D000818:Animals; D003105:Colombia; D004195:Disease Models, Animal; D005243:Feces / Q000469:parasitology; D005849:Gerbillinae / Q000469:parasitology*; D016829:Giardia lamblia / Q000378:metabolism*; D005873:Giardiasis / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans