Genotypic characterization of Cryptosporidium hominis from water samples in São Paulo, Brazil.

• Grant number: 11/12224-5
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: August 01, 2011
• End date: January 31, 2012
• Field of knowledge: Health Sciences - Collective Health - Public Health
• Principal Investigator: Maria Helena Matte
• Grantee: Maria Helena Matte
• Host Institution: Faculdade de Saúde Pública (FSP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The protozoan parasite Cryptosporidium has emerged as one of the most important contaminants of water, causing waterborne outbreaks of diarrheal diseases worldwide. The small size of oocysts under the microscope, and the possibility of changes in characteristics of oocysts, mainly in environmental samples make the taxonomy of the genus very difficult if morphological aspects are considered. This limitation encouraged the application of molecular methods to identify this microorganism. The aim of this study was to detect and identify, by nested-PCR, oocysts of Cryptosporidium present in water samples, in the state of São Paulo, Brazil. Water samples were concentrated through a membrane filter, DNA was extracted by traditional technique, and both amplification reactions used forward and reverse oligonucleotides that are complementary to Cryptosporidium 18S rRNA gene sequences. Thirty water samples, from different sites of collection in the state of São Paulo, were evaluated. Cryptosporidium oocysts were detected in 30% of the samples. By genoptyping, C. hominis and Cryptosporidium sp. were identified in recreational water and C. meleagridis in surface water samples. This is the first report of C. hominis in environmental samples in Brazil. Although identification of Cryptosporidium is still a difficult task, molecular methods are essential for specific identification and a very helpful tool to aid to understand the epidemiology of this parasite in our country. (AU)