A variety of topics grabbed the attention of researchers on Twitter earlier this month, including fish catches, deadly pathogens, engineered vaginas and the nature of peer review.

Based on data from Altmetric.com. Altmetric is supported by Macmillan Science and Education, which owns Nature Publishing Group.

Researchers on Twitter were astounded by some of the figures given in a paper describing extensive illegal fish imports into the United States. According to Tony Pitcher at the University of British Columbia in Vancouver and his colleagues, in 2011 more than 20% of wild-caught seafood coming into the country — worth between US$1.3 billion and $2.1 billion — was from illegal or unreported fishing. To make their estimates, the researchers used data from the US National Marine Fisheries Service for 30 major seafood products from 10 countries. Illegal, unreported and unregulated fishing disrupts ecosystems, food security and livelihoods around the world, the authors say.

Pramod, G., Nakamura, K., Pitcher, T. J. & Delagran, L. Mar. Policy 48, 102–113 (2014)

Haiti was devastated by an earthquake four years ago, but researchers are still discussing the controversy surrounding the origin of the cholera outbreak that subsequently swept the island. Yan Boucher at the University of Alberta in Edmonton, Canada, and his colleagues describe how various research groups sequenced DNA from strains of the cholera bacterium, Vibrio cholerae, to try to pinpoint the outbreak's source. Three years of genomic sequencing studies strongly suggest that the disease was brought in by soldiers from Nepal, rather than evolving in Haiti.

Orata, F. D., Keim, P. S. & Boucher, Y. PLoS Pathog. 10, e1003967 (2014)

Diarrhoea-causing organisms grabbed the spotlight again with this paper showing how a parasitic amoeba nibbles on human cells. William Petri Jr at the University of Virginia in Charlottesville and his co-workers found that Entamoeba histolytica bites off and ingests pieces of living cells until the cells die, and then spits out the remnants. The authors think that the amoeba attacks the cells not for the nutrients, but as a way to invade and move through the tissue — and even to sense the environment.

Ralston, K. S. et al. Nature http://dx.doi.org/10.1038/nature13242 (2014)

Sticking with human tissue, biomaterials scientists have built a growing list of body parts, including skin and bone. Now they can add the vagina to that list. Anthony Atala at Wake Forest University in Winston-Salem, North Carolina, and his co-authors took tissue from the vulvas of four teenage girls who had been born with missing or underdeveloped vaginas. The researchers cultured the cells and placed them onto collagen-based scaffolds to build vaginas that were then surgically implanted in the patients. A follow-up spanning five to eight years showed that the engineered organs were working normally.

Raya-Rivera, A. M. et al. Lancet http://dx.doi.org/10.1016/S0140-6736(14)60542-0 (2014)

Finally, a December 2012 paper in Neuron on the nature of human intelligence sparked fresh debate on social media this month. Adam Hampshire at Canada's University of Western Ontario and his colleagues asked healthy volunteers inside MRI scanners to perform a battery of cognitive tests that tapped different abilities, such as verbal reasoning and working memory. The authors concluded that different aspects of intelligence involve distinct brain networks, arguing against a 'general' intelligence factor (Hampshire, A., Highfield, R. R., Parkin, B. L. & Owen, A. M. Neuron 76, 1225–1237; 2012 ).

Interest spiked after Richard Haier, emeritus professor at the University of California, Irvine, and his colleagues published a 5 April letter online in the journal Intelligence. In it, they laid out concerns with the earlier work and revealed that Haier had originally been invited to write a Preview highlighting the Neuron paper. That summary article, which noted the concerns, was ultimately not published. The tale is “extraordinary”, tweeted psychologist Neil Martin, one of a number who turned to Twitter to talk about the Haier paper. See the blog Retraction Watch for more details about the saga.

Haier, R. et al. Intelligence http://dx.doi.org/10.1016/j.intell.2014.02.007 (2014)