RESUMO
BACKGROUND: Giardia duodenalis (synonyms G. lamblia and G. intestinalis) is an enteric protozoan parasite of a wide range of mammalian hosts, including humans and various domestic and wild animals. There is considerable genetic variability in G. duodenalis and isolates of this parasite have been divided into eight genetic assemblages. Microsatellites markers can be used to discriminate isolates with a high level of sensitivity. This study was conducted to identify and characterize genomic microsatellites (simple sequence repeats-SSRs), sequences of one- to six-nucleotide motifs repeated in tandem, present in the available genomes of G. duodenalis and to develop new markers that can serve as a tool for detection and for characterizing the genetic diversity of this parasite. METHODOLOGY/ PRINCIPAL FINDINGS: For each genetic assemblage, polymorphism levels for the microsatellite markers were evaluated. After performing the analysis using the MISA and SciRoKo software, 1,853 simple sequence repeats (SSRs) were identified. In all the genomes, trinucleotide repeats were the most common class followed by tetranucleotide. Many of the SSR loci are assemblage-specific, and 36 SSR loci shared among all the genomes were identified. Together with hypothetical proteins, variant-specific surface proteins represented nearly half of the annotated SSR loci. The results regarding the most common repeat among the SSRs led us to infer that positive selection occurred to avoid frameshift mutations. Additionally, based on inter- and intra-genetic assemblages polymorphism analyses, we unveiled previously undetected genetic variation, indicating that the microsatellite markers we developed are useful molecular tools for epidemiological inferences based on population genetics patterns and processes. CONCLUSIONS: There is increasing demand for the development of new molecular markers and for the characterization of pathogens at a higher resolution level. In this study, we present 60 G. duodenalis microsatellites markers that exhibited high polymerase chain reaction (PCR) amplification efficiency among the different genetic assemblages. Twenty of these markers presented nucleotide sequence polymorphisms and may be used as a genotyping tool. The monomorphic markers can be used for the detection of the parasite at the species and genetic assemblage level. These polymorphic markers revealed a genetic diversity that was previously undetectable, thus they can be considered valuable molecular tools for high resolution markers in future studies investigating Giardia and may also be used for epidemiological inferences based on populations genetics patterns and processes.
Assuntos
Giardia/genética , Giardia/isolamento & purificação , Giardíase/parasitologia , Repetições de Microssatélites , DNA de Protozoário/genética , Variação Genética , Genoma de Protozoário , Genótipo , Giardia/classificação , Humanos , Tipagem Molecular , Filogenia , Polimorfismo GenéticoRESUMO
Giardia duodenalis is a flagellated intestinal protozoan responsible for infections in various hosts including humans and several wild and domestic animals. Few studies have correlated environmental contamination and clinical infections in the same region. The aim of this study was to compare groups of Giardia duodenalis from clinical and environmental sources through population genetic analyses to verify haplotype sharing and the degree of genetic similarity among populations from clinical and environmental sources in the metropolitan region of Campinas. The results showed high diversity of haplotypes and substantial genetic similarity between clinical and environmental groups of G. duodenalis. We demonstrated sharing of Giardia genotypes among the different populations studied. The comparison between veterinary and human sequences led us to identify new zoonotic genotypes, including human isolates from genetic assemblage C. The application of a population genetic analysis in epidemiological studies allows quantification of the degree of genetic similarity among populations of Giardia duodenalis from different sources of contamination. The genetic similarity of Giardia isolates among human, veterinary, and environmental groups reinforced the correlation between clinical and environmental isolates in this region, which is of great importance for public health.
Assuntos
DNA de Protozoário/genética , Variação Genética/genética , Genoma de Protozoário/genética , Giardia lamblia/genética , Haplótipos/genética , Animais , Genética Populacional , Giardia lamblia/isolamento & purificação , Giardíase/epidemiologia , Giardíase/parasitologia , Giardíase/veterinária , Humanos , Análise de Sequência de DNARESUMO
Cerebral toxoplasmosis can be highly debilitating and occasionally fatal in persons with immune system deficiencies. In this study, we evaluated the Toxoplasma gondii-specific IgG subclass antibody response in 19 cerebrospinal fluid (CSF) samples from patients with cerebral toxoplasmosis who had a positive IgG anti-T. gondii ELISA standardized with a cyst antigen preparation. There were no significant differences between the rates of positivity and the antibody concentrations (arithmetic means of the ELISA absorbances, MEA) for IgG1 and IgG2, but the rates of positivity and MEA values for these two IgG subclasses were significantly higher than those for IgG3 and IgG4. The marked IgG2 response in CSF from patients with cerebral toxoplasmosis merits further investigation.
Assuntos
Anticorpos Antiprotozoários/líquido cefalorraquidiano , Imunoglobulina G/líquido cefalorraquidiano , Toxoplasma/imunologia , Toxoplasmose Cerebral/líquido cefalorraquidiano , Ensaio de Imunoadsorção Enzimática , HumanosRESUMO
Although giardiasis has been a threat to mankind for thousands of years, this protozoan infection was, until recently, relatively neglected. Giardia duodenalis is recognised as a major cause of parasite-induced diarrhoea in humans and animals, and is currently an important public health problem, placing a heavy burden on both diagnostic and treatment services at health care institutions, mostly in developing countries, but also in highly developed countries. Steady progress in recent years, using a combination of molecular, immunological, and clinical approaches, has substantially increased our understanding of Giardia and important aspects of the clinical manifestations that it causes. The purpose of this review is to provide an overview of the extent of Giardia infection, the implications of water and food in Giardia transmission, new aspects regarding clinical diagnosis and environmental detection, treatment, and some approaches towards prevention and control. A number of future research priorities are also presented.
Assuntos
Giardia lamblia , Giardíase/diagnóstico , Giardíase/terapia , Doenças Negligenciadas/diagnóstico , Doenças Negligenciadas/terapia , Animais , Doenças Transmitidas por Alimentos/parasitologia , Giardia lamblia/isolamento & purificação , Humanos , Doenças Negligenciadas/parasitologia , Água/parasitologiaRESUMO
Protozoan foodborne diseases are generally underrecognized. Toxoplasma gondii is the causative agent of toxoplasmosis, one of the most prevalent parasitic infections to humans and domestic animals. The most likely source of T. gondii occurring through food is the consumption of raw or undercooked meat contaminated with tissue cysts. Sporulated T. gondii oocysts, from the feces of infected cats, present in the environment are a potential source of infection. The ingestion of water contaminated with oocysts and the eating of unwashed raw vegetables or fruits were identified as an important risk factor in most epidemiological studies. This review presents information and data to show the importance of T. gondii transmission by foods.
Assuntos
Toxoplasma/patogenicidade , Toxoplasmose/parasitologia , Toxoplasmose/transmissão , Animais , Manipulação de Alimentos , Parasitologia de Alimentos , Doenças Transmitidas por Alimentos/diagnóstico , Doenças Transmitidas por Alimentos/prevenção & controle , Humanos , Toxoplasma/crescimento & desenvolvimento , Toxoplasmose/diagnóstico , Toxoplasmose/prevenção & controle , Toxoplasmose Animal/microbiologia , Toxoplasmose Animal/transmissão , Água/parasitologiaRESUMO
In April 2009, the centenary of the discovery of the American trypanosomiasis, or Chagas disease, was celebrated. A hundred years after the discovery, little has been invested in diagnostics and treatment because the disease affects mainly poor people in developing countries. However, some changes in the epidemiology of the disease are of great importance today. Chagas disease transmitted through food is a public health concern in all areas where there is a reservoir of Trypanosoma cruzi in wild animals (e.g., mammals and marsupials) and/or where infected triatomine bugs are in contact with human food source items (especially fruits and vegetables). Recently, several outbreaks of illness related to the ingestion of food contaminated with T. cruzi have been recorded in Brazil, Colombia, and Venezuela.
Assuntos
Doença de Chagas/transmissão , Parasitologia de Alimentos , Animais , Animais Selvagens/parasitologia , Brasil/epidemiologia , Doença de Chagas/diagnóstico , Doença de Chagas/prevenção & controle , Colômbia/epidemiologia , Países em Desenvolvimento , Surtos de Doenças , Reservatórios de Doenças , Frutas/parasitologia , Humanos , Parasitemia , Trypanosoma cruzi/crescimento & desenvolvimento , Verduras/parasitologia , Venezuela/epidemiologiaRESUMO
Various researchers have studied the importance of the oral transmission of Chagas' disease since the mid-20th century. Only in recent years, due to an outbreak that occurred in the Brazilian State of Santa Catarina in 2005 and to various outbreaks occurring during the last 3 years in the Brazilian Amazon basin, mainly associated with the consumption of Amazonian palm berry or açaí (Euterpe oleracea Mart.) juice, has this transmission route aroused the attention of researchers. Nevertheless, reports published in the 1960s already indicated the possibility of Chagas' disease transmission via food in Brazil, mainly in the Amazonian region. Recently, in December 2007, an outbreak of Chagas' disease occurred in Caracas, Venezuela, related to ingestion of contaminated fruit juices. The objective of this article is to point out the importance of foodborne transmission in the etiology of Chagas' disease, on the basis of published research and Brazilian epidemiology data.