30 avril 2006

Vulnerability To Measles Among Nursery School Children Risen Sharply

Science Daily — Vulnerability to measles infection has risen sharply among nursery school children in Scotland since 1998, despite recent increases in MMR uptake, reveals research published ahead of print in the Archives of Disease in Childhood.

There are now 25 postcode districts. where more than one in five nursery school children is potentially at risk of catching measles, compared with just three in 1998, when unfounded claims that the vaccine might be linked to autism provoked widespread alarm.

MMR was introduced across the UK in 1988. The recommended schedule is for the first dose to be given at the age of 13 months, with the second dose at between 3 years and 5 years of age.

The researchers looked at the vaccination records for Scotland for all children born between 1987 and 2004, accounting for over one million children.

The records show that the sharpest decline began for children born from 1999 onwards, rather than for those born in 1997 as might be expected. This suggests that the negative publicity had a gradual but cumulative effect, say the authors.

The most affluent sectors of the population tended to either have their children vaccinated early or not at all, the figures show. But parents in the most deprived areas of Scotland tended to delay vaccinating their children.

The increased risks of measles to nursery school children are concerning, particularly in the areas of greatest deprivation, where the risk of measles outbreaks would add to existing health inequalities, say the authors.

Although rates of MMR vaccine uptake have increased across Scotland, these have not yet reached the levels before 1998, and are not expected to reach the levels required for population protection among young schoolchildren, say the authors.

Note: This story has been adapted from a news release issued by BMJ Specialty Journals.

24 mars 2006

The Role Of Evolutionary Genomics In The Development Of Autism

Science Daily — Scientists at the London School of Economics, UK and Simon Fraser University, Canada have described the first hypothesis grounded in evolutionary genomics explaining the development of autism.

In an article to be published in a forthcoming issue of Journal of Evolutionary Biology, Dr Christopher Badcock and Professor Bernard Crespi explore the 'imprinted brain hypothesis' to explain the cause and effect of autism and autistic syndromes such as Asperger's syndrome, highlighted by the book The Curious Incident of the Dog in the Night-Time, which involves selective disruption of social behaviour that makes individuals more self-focussed whilst enhancing skills related to mechanistic cognition.

The 'imprinted brain hypothesis' suggests that competition between maternally and paternally expressed genes leads to conflicts within the autistic individual which could result in an imbalance in the brain's development. This is supported by the fact that there is known to be a strong genomic imprinting component to the genetic and developmental mechanisms of autism and autistic syndromes.

Professor Bernard Crespi from Simon Fraser University, Canada explains: "The imprinted brain hypothesis underscores the viewpoint that the autism spectrum represents human cognitive diversity rather than simply disorder or disability. Indeed, individuals at the highest-functioning end of this spectrum may have driven the development of science, engineering and the arts through mechanistic brilliance coupled with perseverant obsession."

The core behavioural features of autism such as self-focussed behaviour, altered social interactions and language and enhanced spatial and mechanistic cognition and abilities -- as well as the degree to which the brain functions and structures are altered -- also supports this hypothesis.

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Read or download the article for FREE: http://www.blackwell-synergy.com/doi/full/10.1111/j.1420-9101.2006.01091.x.

Note: This story has been adapted from a news release issued by Blackwell Publishing Ltd.