Infectious Diseases News Brief - September 4, 2009

[Current Issue -Table of contents]

Using Satellite Images of Environmental Changes to Predict Infectious Disease Outbreaks

Recent events clearly illustrate a continued vulnerability of large populations to infectious diseases, which is related to changing human-constructed and natural environments.  A single person with multidrug-resistant tuberculosis in 2007 provided a wake-up call to the United States and global public health infrastructure, as the health professionals and the public realized that today's ease of airline travel can potentially expose hundreds of persons to an untreatable disease associated with an infectious agent. Ease of travel, population increase, population displacement, pollution, agricultural activity, changing socioeconomic structures, and international conflicts worldwide have each contributed to infectious disease events. Today, however, nothing is larger in scale, has more potential for long-term effects, and is more uncertain than the effects of climate change on infectious disease outbreaks, epidemics, and pandemics. The researchers discuss advances in the ability to predict these events and, in particular, the critical role that satellite imaging could play in mounting an effective response.

Source: Emerging Infectious Diseases Journal volume 15, number 9, September 2009
http://www.cdc.gov/eid/content/15/9/1341.htm

Predicting Phenotype and Emerging Strains among Chlamydia trachomatis Infections

Chlamydia trachomatis is a global cause of blinding trachoma and sexually transmitted infections (STIs). The researchers used comparative genomics of the family Chlamydiaceae to select conserved housekeeping genes for C. trachomatis multilocus sequencing, characterizing 19 reference and 68 clinical isolates from 6 continental/subcontinental regions. There were 44 sequence types (ST).  Identical STs for STI isolates were recovered from different regions, whereas STs for trachoma isolates were restricted by continent. Twenty-nine of 52 alleles had nonuniform distributions of frequencies across regions (p<0.001).  Phylogenetic analysis showed 3 disease clusters: invasive lymphogranuloma venereum strains, globally prevalent noninvasive STI strains (ompA genotypes D/Da, E, and F), and nonprevalent STI strains with a trachoma subcluster. Recombinant strains were observed among STI clusters.  Single nucleotide polymorphisms (SNPs) were predictive of disease specificity. Multilocus and SNP typing can now be used to detect diverse and emerging C. trachomatis strains for epidemiologic and evolutionary studies of trachoma and STI populations worldwide.

Source: Emerging Infectious Diseases Journal volume 15, number 9, September 2009
http://www.cdc.gov/eid/content/15/9/1385.htm

Increase in reported gonorrhoea cases in Sweden, 2001 - 2008

Gonorrhoea is on the rise in Sweden and in many other European countries. The present report describes and evaluates the gonorrhoea trends in Sweden from 2001 to 2008 when an increase of 32% was reported. Up to 86% of the cases were reported in men, with the highest proportion among heterosexually infected men (41-59% during these years).  Heterosexually infected men more often acquired gonorrhoea abroad, especially in Thailand, whereas women and men who have sex with men were more likely to acquire the infection within Sweden. The recent increase in gonorrhoea cases in Sweden is most likely due to adoption of more risky sexual behaviour (e.g. an increase in the number of sexual partners and the number of new/casual sexual partners and/or low use of condoms) in the Swedish population. Further research regarding more effective identification and description of sexual transmission chains and sexual networks is needed in order to follow the spread of infection and to recognise more effective interventions to prevent the spread of gonorrhoea and also other sexually transmitted infections.

Source: Eurosurveillance 27 August 2009, volume 14, issue 34
http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19315