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Abstract:In parasitology, routine laboratory diagnosis involves conventional methods, such as optical microscopy, used for the morphological identification of parasites. Currently, molecular biology techniques are increasingly used to diagnose parasite structures in order to enhance the identification and characterization of parasites. The objective of the present study was to review the main current and new diagnostic techniques for confirmation of parasite infections, namely: polymerase chain reaction (PCR), real-time polymerase chain reaction (RT-PCR), loop-mediated isothermal amplification (LAMP), Luminex xMAP, random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), and restriction fragment length polymorphism (RFLP), in addition to microsatellites. Molecular assays have comprehensively assisted in the diagnosis, treatment and epidemiological studies of parasitic diseases that affect people worldwide, helping to control parasitic disease mortality.Key words: parasite infection, diagnosis, molecular techniques, molecular epidemiology. Review ARticle The Journal of Venomous Animals and Toxins including Tropical Diseases ISSN 1678-9199 | 2011 | volume 17 | issue 3 | pages 239-248 INTRODUCTIONIn parasitology, routine laboratory diagnosis involves conventional methods, such as optical microscopy, used for the morphological identification of parasites (1). However, the occasional difficulty of identifying these parasite structures may decrease the sensitivity of such methods. Currently, because of these difficulties, molecular biology has been employed to detect parasites responsible for parasitic diseases (2).Traditional parasitological analyses have the advantage of being less costly without requiring expensive reagents and equipment. Additionally, such analyses can be easily performed when a trained microscopist is available. On the other hand, molecular technology demonstrates the presence of parasites based on their antigenic components or DNA segments (3). These tests are not influenced by environmental factors that usually can interfere with the results of a stool test, for example, thus ensuring highly reliable results (4).Current laboratory diagnostic methods for the identification of parasites include: polymerase chain reaction (PCR), random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), restriction fragment length polymorphism (RFLP), microsatellite marker method, Luminex xMAP-based technology (areas of multianalyte profiling), loop-mediated isothermal amplification (LAMP), and the recently added real-time PCR (5-12).The objective of the present article was to review the applications of molecular biology techniques in parasitology by evaluating and discussing their uses and benefits. MOLECULAR METHODS FOR DETECTION OF PARASITE STRUCTURESSeveral molecular tests to detect parasites have been developed in the last decade. Their specificity and sensitivity have gradually increased, and parasites that were previously difficult to diagnose usi...

A novel SYBR® green-real time polymerase chain reaction (qPCR) was developed to detect two Bartonella species, B. henselae and B. clarridgeiae, directly from blood samples. The test was used in blood samples obtained from cats living in animal shelters in Southern Brazil. Results were compared with those obtained by conventional PCR targeting Bartonella spp. Among the 47 samples analyzed, eight were positive using the conventional PCR and 12 were positive using qPCR. Importantly, the new qPCR detected the presence of both B. henselae and B. clarridgeiae in two samples. The results show that the qPCR described here may be a reliable tool for the screening and differentiation of two important Bartonella species.

Around the world, enteric viruses are often found in surface waters. This study set out to evaluate the occurrence of adenoviruses (AdVs) in water samples, and its relation to different physical, chemical, and bacteriological parameters [total coliform (TC) and fecal coliform (FC), represented by Escherichia coli]. Monthly samples of 500 ml of raw water were collected from May 2011 to June 2013 in eight abstraction points water treatment stations along three stretches of the Sinos River Basin (SRB), in Southern Brazil and, subsequently, were analyzed using real-time polymerase chain reaction (qPCR). AdVs from different species, from human (HAdV), and from other animals (CAV1-2, BAdV, PAdV, and AvAdV) were detected along the three stretches of the basin, indicating fecal contamination from different sources and proving the inefficiency of the wastewater treatment in the waters of the SRB and intensifying the strong influence of human activities that can contribute to the presence of inhibitory substances such as organic acids in surface of these waters. Statistical analyses revealed no significant correlations between the concentrations of TC and FC and the concentrations of AdVs. We observed a small, nonconstant, and unstable correlation between viruses and physicochemical parameters. These correlations were not sufficiently consistent to establish a reliable association; therefore, this study corroborates that only the viral assay itself is reliable for the diagnosis of fecal contamination by viruses in environmental samples.

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Hepatitis E virus (HEV) is highly disseminated among swine herds worldwide. HEV is also a threat to public health, since particularly genotypes 3 and 4 may cause acute hepatitis in human beings. No previous studies were done on the occurrence of HEV in environmental samples in Rio Grande do Sul, Brazil. In the present study, reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to detect the presence of HEV in swine feces and in effluents from slurry lagoons in farms located in the municipality of Teutônia, inside the area of swine husbandry in the state. Pooled fecal samples from the floor of pig barns from 9 wean-to-finish farms and liquid manure samples were collected from the slurry lagoons from 8 of these farms. From the pooled fecal samples, 8/9 were positive for the HEV ORF1 gene by RT-PCR; all the slurry lagoon samples were positive for HEV RNA (100%). The identity of the HEV ORF1 amplicons was confirmed by sequencing belonging to HEV genotype 3, which was previously shown to be circulating in South America.Keywords: Hepatitis E virus, swine HEV, slurry, zoonosis RESUMOO vírus da hepatite E (HEV) é altamente disseminado entre rebanhos suínos no mundo todo. O HEV é também uma ameaça à saúde pública, já que os genótipos 3 e 4 podem causar hepatite aguda em seres humanos. Não há estudos anteriores sobre a ocorrência de HEV em amostras ambientais no Rio Grande do Sul. No presente estudo, empregou-se transcrição reversa e reação em cadeia da polimerase (RT-PCR) para detectar a presença de HEV em fezes de suínos e efluentes de lagoas de chorume em fazendas localizadas no município de Teutônia, representativo da região de maior produção de suínos no estado. Pools de amostras fecais foram coletadas a partir do chão de galpões de suínos provenientes de 9 propriedades de terminação; outra amostra de esterco líquido foi coletada das lagoas de chorume de 8 dessas fazendas. A partir das amostras fecais reunidas, 8/9 foram positivas para o gene ORF1 de HEV por PCR convencional; todas as amostras de lagoas de chorume foram positivas para RNA de HEV (100%). A identificação dos produtos de amplificação de HEV ORF1 foi confirmada por sequenciamento pertencente ao HEV genótipo 3, o qual foi previamente detectado na América do Sul.

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