Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases
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Infect. Genet. Evol. · Aug 2011
SP-A1, SP-A2 and SP-D gene polymorphisms in severe acute respiratory syncytial infection in Chilean infants.
Respiratory syncytial virus (RSV) is the principal pathogen that causes acute lower respiratory tract infection (ALRI) in infants. Severe RSV-ALRI has been associated with the host genetic susceptibility. To assess whether severe RSV disease in infants is associated with certain single nucleotide polymorphism (SNP) into the gene of SP-A1, SP-A2 and SP-D, a prospective study was performed among blood donors and RSV-infected infants aged
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Infect. Genet. Evol. · Aug 2010
Genetic determinants of virulence, antibiogram and altered biotype among the Vibrio cholerae O1 isolates from different cholera outbreaks in India.
Cholera diarrhea is still a major health challenge for a large part of globe. Global replacement of Vibrio cholerae classical biotype by El Tor biotype, emergence of O139 serogroup and rapid spread of antibiotic resistant strains indicate the continuous evolution in V. cholerae. In this study, 114 V. cholerae O1 serotype Ogawa isolates, collected from different cholera outbreaks in different regions of India between 2004 and 2007 were subjected to biochemical, immunological and molecular characterization. ⋯ This study also substantiated the wide spread of class 1 integrons and SXT elements (mobile genetic elements for antibiotic resistance) in clinical isolates in India. Sequencing of cholera toxin (ctxB) gene revealed the replacement of traditional ctxB of El Tor biotype with ctxB of classical biotype in all the O1 El Tor strains collected since 2004. In addition, in 2007, a new variant of O1 El Tor strain with further modifications in ctxB of classical biotype is discovered among the Indian isolates.
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Infect. Genet. Evol. · Jan 2009
Ancestral Mycobacterium tuberculosis genotypes in India: implications for TB control programmes.
It has been a decade since the genome sequence of Mycobacterium tuberculosis was unraveled. The fruits of genomic technologies are yet to reach high burden countries such as India, where tuberculosis (TB) kills a huge number of patients. Paradoxically, despite increased cases of human immunodeficiency virus (HIV) infection and diabetes mellitus, TB cure rates in India have been consistently improving during the DOTS program. ⋯ Virulence and dissemination potentials of these ancestral strains are speculated to be 'low' as compared to the other 'aggressive' strains such as Beijing and LAM, which are expected to be more widespread in future, also in synergy with HIV and diabetes epidemics. We discuss the implications of the high prevalence of ancestral strains on TB control in India. It appears that despite a hypothetical 'ancestral advantage', future dynamics of tubercle bacilli in the back drop of surging HIV and diabetes incidences may pose a major healthcare problem in India in the years to come.
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Explaining the adaptive value of sex is one of the great outstanding problems in biology. The challenge comes from the difficulty in identifying the benefits provided by sex, which must outweigh the substantial costs of sex. Here, we consider the adaptive value of sex in viruses, bacteria and fungi, and particularly the information available on the adaptive role of sex in pathogenic microorganisms. ⋯ However, in the long-term, sex may help get rid of mutations, increase the rate of adaptation of the population, and, in pathogens, may infrequently create new infective strains. An additional general issue about sex illustrated by pathogens is that some of the most interesting consequences of sex are not necessarily the reasons for which sex evolved. For example, antibiotic resistance may be transferred by bacterial sex, but this transfer is probably not the reason sex evolved in bacteria.
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Infect. Genet. Evol. · Mar 2006
Historical ArticleOn the phylogenetic placement of human T cell leukemia virus type 1 sequences associated with an Andean mummy.
Recently, the putative finding of ancient human T cell leukemia virus type 1 (HTLV-1) long terminal repeat (LTR) DNA sequences in association with a 1500-year-old Chilean mummy has stirred vigorous debate. The debate is based partly on the inherent uncertainties associated with phylogenetic reconstruction when only short sequences of closely related genotypes are available. However, a full analysis of what phylogenetic information is present in the mummy data has not previously been published, leaving open the question of what precisely is the range of admissible interpretation. ⋯ We then deduced possible phylogenetic positions for the two main categories of published Chilean mummy sequences, based on their published 157-nucleotide LTR sequences. The possible phylogenetic placements for one of the mummy sequence categories are consistent with a modern origin. However, one of these placements for the other mummy sequence category falls very close to the root of the Cosmopolitan clade, consistent with an ancient origin for both this mummy sequence and the Cosmopolitan clade.