Linked Life Data

15604477

Source:http://linkedlifedata.com/resource/pubmed/id/15604477

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2004-12-17
pubmed:abstractText
Ehrlichia ruminantium, the agent of cowdriosis transmitted by Amblyomma ticks, presents an extensive genetic and antigenic diversity of key importance for vaccine formulation. Two means of nested polymerase chain reaction (PCR) targeting were developed to conduct molecular epidemiology studies in the Caribbean and Africa. The first used a conserved DNA fragment for detection of the pathogen in animals and vectors, and the second relied on the polymorphic map1 gene for genotyping. As compared to a PCR, the nested PCR showed a 2-Log10 improvement of sensitivity and allowed amplification from ticks, blood, brain, and lungs from infected animals, providing a more accurate picture of the tick infection rate. In Guadeloupe, this rate reached 36% (N = 212) instead of 1.7% (N = 224), as previously estimated. Genetic typing was done by restriction fragment length polymorphism or sequencing of map1 amplification products. Molecular epidemiology studies conducted in field sites selected for vaccination trials with inactivated vaccine, revealed the circulation of genetically divergent strains in limited geographical areas. It is known, then, that genetic clustering based on map1 has no predictive value regarding the protective value of a given strain against a new strain. However, tracing the strains by this technique revealed the extent of E. ruminantium diversity that one can expect in a given region, and the method allows differentiation between an inadequate immune response and the challenge by a breakthrough strain on animals dying despite vaccination. Up to now, genetic typing does not avoid cross-protection studies, which were conducted in parallel, although on a more limited scale. The importance of pathogen diversity studies for optimization of vaccine design is discussed as well as the research for new polymorphic genes. These genes may allow better predictions on cross-protection, given the recent completion of the sequence of the full genome of two E. ruminantium strains.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0077-8923
pubmed:author
pubmed:issnType
Print
pubmed:volume
1026
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
106-13
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Nested PCR for detection and genotyping of Ehrlichia ruminantium: use in genetic diversity analysis.
pubmed:affiliation
CIRAD, Guadeloupe, France. dominique.martinez@cirad.fr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't