Fruit flies demonstrate increasing resistance to CRISPR gene drives
Gene drives using CRISPR/Cas9 gene editing technology aim to spread new genes within a natural population in efforts to prevent the spread of mosquito-borne diseases and control invasive species. However, this new approach to alter the genetics of a population can also create resistant genetic sequences and organisms that cannot be converted. To investigate the rise of resistance, researchers tested two different CRISPR gene drive constructs in the fruit fly Drosophilia melanogaster and found that resistant gene variations formed frequently, especially in insects with genetically diverse backgrounds.
This PLOS Genetics study suggests that evolution of resistance will likely complicate existing CRISPR gene drive approaches, and will need to be addressed before scientists can successfully use them in genetically diverse, natural populations.
Google searches can help track dengue outbreaks in less-developed countries
Dengue, a mosquito-borne virus that infects about 390 million people each year, is tough to monitor with traditional hospital-based reporting in underdeveloped countries due to inefficient resources for surveillance and communication. However, a new study published in PLOS Computational Biology found that a mathematical modeling tool that tracks internet search data may be able to track the disease.
The researchers used Google’s “Trends” tool to track the top dengue-related search queries made by users in Mexico, Brazil, Thailand, Singapore and Taiwan. They also used historical dengue data from government health agencies and input both datasets into the tool to calculate near real-time estimates of dengue prevalence in each country. Compared to five other methods, the researchers found that they obtained more accurate estimates for dengue prevalence using the tool than any other method, highlighting the potential for Google searches to enable accurate, timely tracking of mosquito-borne diseases in less-developed countries that lack surveillance systems to track the disease.
Risk of hantavirus estimated to increase by 20 percent in Brazil
Hantavirus is a deadly disease that is typically spread in tropical areas by rodents. Previous studies have found that the expansion of sugarcane, a common occurrence in the developing world, increases the population of hantavirus-carrying rodents. Additionally, climate change has been hypothesized to boost rodent numbers and the amount of time hantavirus can remain in the environment.
New research from PLOS Neglected Tropical Diseases analyzed historical data from 1993 to 2012 on the virus, air temperatures and sugarcane growth to develop a forecasting model to predict how climate change and sugarcane expansion might affect hantavirus cases. The researchers estimate that by 2050, climate change and land use changes will increase the risk of hantavirus in the Brazilian state of São Paulo by more than 20 percent. The researchers say, “These findings should be considered as an additional argument to encourage governments, companies and citizens to sign agreements and start massive campaigns in order to mitigate climate change impacts.”
Image Credit: Jackson Champer
Champer J, Reeves R, Oh SY, Liu C, Liu J, Clark AG, et al. (2017) Novel CRISPR/Cas9 gene drive constructs reveal insights into mechanisms of resistance allele formation and drive efficiency in genetically diverse populations. PLoS Genet 13(7): e1006796. https://doi.org/10.1371/journal.pgen.1006796
Yang S, Kou SC, Lu F, Brownstein JS, Brooke N, SantillanaM (2017) Advances in using Internet searches to track dengue. PLoS Comput Biol 13(7): e1005607. https://doi.org/10.1371/journal.pcbi.1005607
Prist PR, Uriarte M, Fernandes K, Metzger JP (2017) Climate change and sugarcane expansion increase Hantavirus infection risk. PLoS Negl Trop Dis 11(7): e0005705. https://doi.org/10.1371/journal.pntd.0005705