Table of Contents
ISRN Parasitology
Volume 2013, Article ID 713958, 7 pages
Research Article

Infectivity of Giardia duodenalis Cysts from UV Light-Disinfected Wastewater Effluent Using a Nude BALB/c Mouse Model

1Laboratory of Oxidation Processes, Department of Sanitation and Environment, School of Civil Engineering, Architecture and Urbanism, University of Campinas (UNICAMP), C.P. Box 6021, 13083-852 Campinas, SP, Brazil
2CEMIB Multidisciplinary Centre for Biological Investigation, University of Campinas (UNICAMP), C.P. Box 6095, 13083-877 Campinas, SP, Brazil
3Laboratory of Helminthology, Department of Parasitology, Institute of Biology, University of Campinas (UNICAMP), C.P. Box 6109, 13083-970 Campinas, SP, Brazil
4Laboratory of Microbiology, Society for Water Supply and Sanitation (SANASA), Street Abolição 2.375, 13045-750 Campinas, SP, Brazil
5Laboratory of Genetic and Molecular Analysis, Center of Molecular Biology and Genetic Engineering (CBMEG), Institute of Biology, University of Campinas (UNICAMP), C.P. Box 6109, 13083-875 Campinas, SP, Brazil
6Laboratory of Protozoology, Department of Animal Biology, Institute of Biology, University of Campinas (UNICAMP), C.P. Box 6109, 13083-970 Campinas, SP, Brazil

Received 7 December 2012; Accepted 27 December 2012

Academic Editors: S. Das and G. Mkoji

Copyright © 2013 Luciana Urbano dos Santos et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Giardia duodenalis is a protozoan of public health interest that causes gastroenteritis in humans and other animals. In the city of Campinas in southeast Brazil, giardiasis is endemic, and this pathogen is detected at high concentrations in wastewater effluents, which are potential reservoirs for transmission. The Samambaia wastewater treatment plant (WWTP) in the city of Campinas employs an activated sludge system for sewage treatment and ultraviolet (UV) light for disinfection of effluents. To evaluate this disinfection process with respect to inactivating G. duodenalis cysts, two sample types were investigated: (i) effluent without UV disinfection (EFL) and (ii) effluent with UV disinfection (EFL+UV). Nude immunodeficient BALB/c mice were intragastrically inoculated with a mean dose of 14 cysts of G. duodenalis recovered from effluent from this WWTP, EFL, or EFL+UV. All animals inoculated with G. duodenalis cysts developed the infection, but animals inoculated with UV-exposed cysts released a lower average concentration of cysts in their faeces than animals inoculated with cysts that were not UV disinfected. Trophozoites were also observed in both groups of animals. These findings suggest that G. duodenalis cysts exposed to UV light were damaged but were still able to cause infection.