Abstract
The flagellated protozoan Giardia lamblia is a recognized public health problem. Intestinal infection can result in acute or chronic diarrhea with associated symptoms in humans. As part of a study to evaluate removal of G. lamblia cysts from drinking water by the processes of coagulation and dual-media filtration, we developed a methodology by using 5.0-microns-porosity membrane filters to evaluate the filtration efficiency. We found that recovery rates of G. lamblia cysts by membrane filtration varied depending upon the type and diameter of the membrane filter. Examination of membrane-filtered samples by scanning electron microscopy revealed flexible and flattened G. lamblia cysts on the filter surface. This feature may be responsible for the low recovery rates with certain filters and, moreover, may have implications in water treatment technology. Formation of the cyst wall is discussed. Electron micrographs of cysts apparently undergoing binary fission and cysts exhibiting a possible bacterial association are shown.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Barlough J. E. Canine giardiasis: a review. J Small Anim Pract. 1979 Oct;20(10):613–623. doi: 10.1111/j.1748-5827.1979.tb06670.x. [DOI] [PubMed] [Google Scholar]
- CHEISSIN E. M. ULTRASTRUCTURE OF LAMBLIA DUODENALIS. I. BODY SURFACE, SUCKING DISC AND MEDIAN BODIES. J Protozool. 1964 Feb;11:91–98. doi: 10.1111/j.1550-7408.1964.tb01725.x. [DOI] [PubMed] [Google Scholar]
- Friend D. S. The fine structure of Giardia muris. J Cell Biol. 1966 May;29(2):317–332. doi: 10.1083/jcb.29.2.317. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hemmes D. E., Hohl H. R. Ultrastructural aspects of encystation and cyst-germination in Phytophthora parasitica. J Cell Sci. 1971 Jul;9(1):175–191. doi: 10.1242/jcs.9.1.175. [DOI] [PubMed] [Google Scholar]
- Nemanic P. C., Owen R. L., Stevens D. P., Mueller J. C. Ultrastructural observations on giardiasis in a mouse model. II. Endosymbiosis and organelle distribution in Giardia muris and Giardia lamblia. J Infect Dis. 1979 Aug;140(2):222–228. doi: 10.1093/infdis/140.2.222. [DOI] [PubMed] [Google Scholar]
- Sheffield H. G., Bjorvat B. Ultrastructure of the cyst of Giardia lamblia. Am J Trop Med Hyg. 1977 Jan;26(1):23–30. doi: 10.4269/ajtmh.1977.26.23. [DOI] [PubMed] [Google Scholar]