PHENOTYPIC AND GENOTYPIC VARIATION IN GIARDIA LAMBLIA

Phenotypic and genotypic variation in Giardia lamblia isolates during chronic infection.

Two Giardia isolates were axenised in vitro after recovery by duodenal aspiration from a man with hypo-gamma globulinaemia and chronic giardiasis, before and after three unsuccessful courses of metronidazole. In vitro drug sensitivity assays showed that the pretreatment isolate was sensitive to metronidazole with minimum inhibitory concentration (MIC) and dose that inhibited growth by 50% (ED50...

Regulation of antigenic variation in Giardia lamblia.

Antigenic variation, a clonal phenotypic variation developed by microorganisms, involves the permanent switching of homologous, antigenically different cell surface molecules. In pathogenic microorganisms, antigenic variation is often described as a mechanism to evade the host immune system and therefore is responsible for the generation of chronic and/or recurrent infections. However, antigeni...

Antigenic variation of Giardia lamblia in vivo.

A single Giardia lamblia trophozoite can give rise in vitro to G. lamblia with varying surface antigens. To determine whether antigenic variation also occurs in vivo, gerbils were inoculated with defined G. lamblia clones and the surface antigens of the intestinal trophozoites were studied at different times during the infection. The proportion of monoclonal antibody 6E7-reacting trophozoites f...

Giardia Lamblia.

Giardia lamblia and Giardiasis

Introduction Ask the average outdoors person about Giardia lamblia, and they have certainly heard about it. Almost always, however, they are considerably misinformed about both the organism’s significance in wilderness water and the seriousness of the disease, giardiasis, if contracted. The amount of information easily found on the subject is voluminous. Unfortunately, almost all of it is flawe...