Μοριακή τυποποίηση εντεροϊών αδενοϊών και ρότα ιών σε λύματα

Abstract

Enteroviruses have been associated with outbreaks of waterborne non-bacterial gastroenteritis and are of important concern for public health. Significant numbers of viruses can be isolated from faeces and urine of humans as well as from sewage and polluted waters. Adenoviruses are also pathogenic to humans and their presence in environmental samples (polluted waters) may cause infections. Like rotaviruses, adenoviruses are causative agents of gastroenteritis, are the only human enteric viruses to contain DNA and many serotypes are difficult to culture in regular cell lines For this reason, and because adenoviruses are slow growing, their presence in polluted water and their role as originators of gastroenteritis have probably been underestimated. Rota viruses are responsible for severe gastroenteritis in humans and animals. After replicating in the gastrointestinal tract, these viruses are excreted and may be dispersed in environmental waters. Rota viruses have been implicated in waterborne gastroenteritis outbreaks in many countries. The stability of human rotaviruses in environmental water and their resistance to physicochemical treatment processes in sewage treatment plants may facilitate their transmission. In the present study, enteroviruses, adenoviruses and rota viruses were detected in raw sewage samples from inlets of four biological treatment plants in Greece (two in Athens, two in Patras}. Raw sewage samples (118) were analyzed for the presence of these viruses during the period September 2000 to September 2003. Our approach consisted of a simple concentration of viruses from raw sewage followed by RT-nested PCR in order to increase the sensitivity of virus detection. The viral sequences detected were then characterized by nucleotide sequencing analysis. Rota viruses were detected in 17 samples (14.2%). Sequencing analysis of the positive sewage samples revealed the presence of rotavirus type G1 (88.2%) and type G2 (11.8%). Adenoviruses were found in 55 samples (45.8%). Sequencing analysis of the positive sewage samples revealed the presence of adenovirus group F type 40 (34.6%), type 41 (63.6%) and group C type 2 (1.8%). Enteroviruses were detected in 30 samples (40%) and sequencing analysis of the positive sewage samples revealed the presence of several types such as (a) coxsackievirus types (A6 - 3.3%, A9 - 3.3%, A16 - 3.3%, B4 - 16.7%, B5 - 3.3%), (b) echovirus types (2 -6.7%, 6 - 13.3%, 30 -10%), (c) enterovirus types (68 - 3.3%, 71 - 13.3%) as well as porcine enterovirus (6.7%). poliovirus 1 (6.7%) and poliovirus 2 (10%). Water quality and, therefore human health, may be significantly affected by the presence of pathogenic enteric microorganisms derived from sewage discharged to the aquatic environment. Outbreaks of enteric virus disease have been linked to water at various times and to different causes. Waterborne disease may be transmitted by consumption of polluted drinking water, by immersion in recreational water or by contact with skin or inhalation. Raw sewage was found to be contaminated by different types of enteric viruses that mainly cause gastroenteritis; therefore, it is necessary to use the most efficient water treatment measures in sewage treatment plants. Sequencing analysis showed the presence of human rotavirus A type G1 and G2 which cause childhood diarrhea worldwide and enteric adenoviruses (types 40 and 41) which are important etiological agents of pediatric gastroenteritis, principally in temperate climates. On the other hand, the variety of enteroviruses identified in the raw sewage samples was more extensive compared to the other viruses of the study. The present study demonstrated the efficiency of the nucleotide sequencing analysis for studying epidemiological relationships between strains involved in human infections and those found in raw sewage.