CICLO BIOLOGICO DE ECHINOCOCCUS GRANULOSUS PDF

Correspondence to :. In Chile is a zoonosis of great importance. Hence, it was discovered that in endemic areas of hydatidosis there could be several strains and genotypes of EG. In addition, there is evidence that some strains and genotypes are more infectious for human beings than others. This interesting phenomenon of the biology of EG has been studied using molecular biology techniques based on polymerase chain reaction PCR and DNA sequence analysis, which has made it possible to characterize the cestode species complex called EG sensu lato s l as being comprised of EG sensu stricto s.

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Correspondence to :. In Chile is a zoonosis of great importance. Hence, it was discovered that in endemic areas of hydatidosis there could be several strains and genotypes of EG. In addition, there is evidence that some strains and genotypes are more infectious for human beings than others. This interesting phenomenon of the biology of EG has been studied using molecular biology techniques based on polymerase chain reaction PCR and DNA sequence analysis, which has made it possible to characterize the cestode species complex called EG sensu lato s l as being comprised of EG sensu stricto s.

Genotypes G1-G3 , E. The aim of this manuscript is to describe the different genotypes of EG described in humans and different livestock host reported in the literature. En Chile hay una zoonosis de gran importancia. El objetivo de este manuscrito fue describir los diferentes genotipos de EG descritos en humanos y diferentes animales de ganado reportados en la literatura. Echinococcus granulosus EG is the major cause of cystic echinococcosis in humans and livestock in the world.

In Chile is a zoonosis of great importance, as it constitutes a public health problem with strong socio-economic repercussions. The prevalence is 5 per The high incidence and prevalence in these areas causes serious public health problems, including, it must be noted, the appearance of advanced stages of the disease with unusual forms of presentation and various types of complications of the lesions Manterola et al.

In a study of the economic impact of human and animal echinococcosis in Chile, it was confirmed that i in , patients were treated surgically for hydatidosis, ii the annual costs derived from surgical treatment alone were estimated at USD 2. Therefore, this situation suggests a need to propose solutions that can be based on at least 4 possible perspectives: education of the population particularly those most susceptible to being infected , early diagnosis especially in endemic areas , identification of risk factors measure designed to recognize promptly those patients at greatest risk of disease-related morbidity and mortality , and the creation of a vaccine.

A great objective of these types of studies would be to develop vaccines against some specific genotypes. In this respect, some studies describe the difficulty of this initiative, given that the antigen of the protection vaccine EG95 , developed for the G1 genotype, is immunologically different in the G6 genotype; therefore, greater evidence is needed to determine whether the EG95 vaccine would be effective against the G6 or G7 genotypes, or if it would be necessary and possible to develop specific vaccines for each genotype Alvarez Rojas et al.

The sequence of the full length of the cytochrome c oxidase subunit I COI bp gene was analyzed in 37 EG isolates from different hosts and geographic regions in Australia, obtaining 7 haplotypes of EG s. Such evidence points to further studies being required in the area Alvarez Rojas et al. Daughter's vesicles of a hydatid cyst of the liver in a human host.

Protoscolex obtained from hydatid sand of a human hydatid cyst. EG is one of the smallest tapeworms in the Taeniidae family.

Subspecific variants or strains have been identified, and a review of the taxonomy of the genus Echinococcus Thompson et al. These subspecific variants are around 10 genotypes distinct from the parasite G1 to G10 Bowles et al.

Several techniques have been applied to the direct study of the genetic variability of EG. Previous studies into the identification and characterization of genotypes of EG have revealed the existence of nine genotypes, which have been linked to different animals, such as sheep, pigs, horses, camels, cattle, goats, etc.

Cuesta-Bandera et al. This method has proven to be fast and reliable, and has advantages over other techniques larval morphology, in vitro development, isoenzyme standards and SDS-PAGE proteins ; for example, RAPD can be used on infertile cysts because it requires small amounts of parasitic tissue, while it can also be applied to specimens that are fresh, frozen or fixed in alcohol. Nevertheless, the RAPD method has some drawbacks: it is very sensitive to changes in the reaction conditions Olivier et al.

This method has an adequate internal and external validity, which makes it interesting to reproduce in other centers. A PCR, followed by sequencing, on the mitochondrial genes COI and Nad1 is the gold standard test at laboratory level for addressing both the Taenia sp.

The polymorphisms in these genes are so useful for typing Roelfsema et al. In this light, EG is considered a tapeworm parasite of great medical and veterinary importance, as it is responsible for cystic echinococcosis, a condition that is among the most serious parasitic diseases in human beings, representing 1 of the 17 neglected diseases prioritized by the Word Health Organization Laurimaa et al.

Bowles et al. On the other hand, when they applied the mitochondrial ND1 sequence protocol, they observed a similarity with the G6 genotype common in the camel and the G7 usual in pigs. The reactions observed support the notion that the "northern strain" of EG is a special genotype designated G8 Bowles et al.

Siles-Lucas et al. Scott et al. The samples were processed by nuclear ITS1 and mitochondrial sequencing ND1 and then by application of restriction enzymes, observing that the Polish patients were not infected with the G1 genotype associated with sheep and human infection , but rather a genotype similar to G7 characteristic of pigs was isolated in these patients, which represented a different genotype of EG that was called G9 Scott et al.

Zhang et al. The samples were obtained from sheep, cattle, camels and operated human hydatid cysts. After applying a DNA sequencing protocol to the mitochondrial cytochrome c oxidase subunit 1 and NADH dehydrogenase genes, they determined the existence of G6 from camels and G1 from sheep and humans.

The latter genotype was isolated exclusively in samples from the northern area of Xinjiang Uygur Zhang et al. The samples were treated using a protocol to analyze the DNA nucleotides and to predict the sequence variations of the amino acids in the mitochondrial cytochrome c oxidase subunit 1 and NADH dehydrogenase genes. After applying a PCR and restriction enzymes, they found two different G6 from dogs and camels and G1 from sheep, domestic animals and humans genotypes Zhang et al. They extracted the complete genomic DNA, then amplified the DNA and this was automatically sequenced with a fluorescence base.

The digested DNA samples were subjected to electrophoresis and hybridizations were done at 68 C. The protocols made it possible to distinguish 2 genetic groups within the Spanish pig isolates: the G1 sheep strain and G7 pig strain genotypes.

Le et al. Lavikainen et al. They observed that the analyzed samples were similar to the G6 genotype; however, and according to the phylogenetic analysis, the isolates were also associated with the G7, G5 and G8 genotypes; as a result, it was considered that they were dealing with a new genotype, which they called "Fennoscandian cervid strain" and assigned it the G10 genotype Lavikainen et al.

Guarnera et al. They found the G1 genotype associated with common sheep in 19 patients; the G2 genotype related to sheep in Tasmania in 6 patients, the G5 genotype linked to cattle in 1 patient, and the G6 genotype associated with camels in 15 patients. This finding is peculiar because the camel is not a common animal in Argentina Guarnera et al. Daniel Mwambete et al.

They worked with isolates from hepatic and pulmonary cysts with a similar degree of fertility. They extracted the genomic DNA of the protoscolices or germinal membranes. They later applied PCR amplification reactions, finding 3 different genotypes: G1 highly fertile and preference for sheep , G4 no host preference and located exclusively in the liver of the infested animal , and G7 preference for pigs, in which greater fertility was observed in hepatic than in pulmonary cysts Daniel-Mwambete et al.

Mrad et al. Boufana et al. The "Abbasi" primers only detected The "Dinkel" primers also showed crossed reactivity between species Manterola et al. The genotype was confirmed using the sequence of a fragment of base pairs from a mitochondrial gene COI.

The DNA of protoscolices from 24 samples 4 from pulmonary cysts and 20 from hepatic cysts was analyzed. The fragment of bp was amplified in 20 of the 24 samples The enzymatic digestion Fig. Casulli et al. The DNA of 59 isolates was amplified. Soriano et al. Isolates from infected dogs adult worms from 10 dogs were also analyzed. They identified a total of 67 strains by DNA sequencing of mitochondrial cytochrome C oxidase subunit 1.

They detected E. This was the first study to describe the existence of EG senso estricto G3 in South America and to verify that goats act as a reservoir of E. In lanes 2, 4, 5, 6 and 7 positive samples. In lane 3, sample not amplified. In lane 2 no amplified product. In lines 3, 4, 5 and 6 positive samples for enzymatic digestion. In line 7 marker bp.

Nakao et al. Thus, they obtained 68 strains of EG senso estricto S. Additionally, strains of EG s. Molecular identification using mitochondrial and nuclear markers was identical, suggesting a low frequency of introgressive hybridization Nakao et al. Aaty et al. It was concluded that G6 is the predominant genotype in Egypt Aaty et al. Andresiuk et al. Using sequencing with mitochondrial COI and nad1 genes, they verified that the predominant genotype was G1, with the exception of two identified as G2 and G5 Andresiuk et al.

The sensitivity of the three DNA detection techniques was between 2 and 10 gp. Konyaev et al. In addition, 4 genotypes of E. Espinoza et al. The phylogenetic analysis showed that most of the analyzed samples were G1; however, a sample of the cysts from a bovine lung Q21 , with the COI marker, was grouped in a node together with a sample belonging to the G3 genotype.

In the phylogenetic tree obtained with the ND1 marker, this sample was grouped with the sequences of the G3, G2, and G4 genotypes. These results were significant as G2 and G3 had not been described previously in Chile Espinoza et al. They identified EG sensu stricto, from all the host species examined, E. A single haplotype EqTu01 was identified by the nucleotide sequences of equine Echinococcus Boufana et al.

Alvarez Rojas et al. The G1 genotype is responsible for most of the human cystic echinococcosis The G6 and G7 genotypes closely related cause a significant number of human infections

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Echinococcosis

Human echinococcosis hydatidosis, or hydatid disease is caused by the larval stages of cestodes tapeworms of the genus Echinococcus. Another species, E. Two exclusively New World species, E. Many genotypes of E.

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