Greaves M, Hughes W. Cancer cell transmission via the placenta. Evolution, Medicine, and Public Health. 2018 Jan 1;2018(1):106–15. (open access

Abstract: Cancer cells have a parasitic propensity in the primary host but their capacity to transit between individuals is severely restrained by two factors: a lack of a route for viable cell transfer and immune recognition in allogeneic, secondary recipients. Several examples of transmissible animal cancers are now recognised. In humans, the only natural route for transmission is via the haemochorial placenta which is permissive for cell traffic. There are three special examples of this occurring in utero: maternal to foetus, intraplacental twin to twin leukaemias and choriocarcinoma-extra-embryonic cells to mother. We discuss the rare circumstances under which such transmission occurs.

Bailey, E. S., Choi, J. Y., Fieldhouse, J. K., Borkenhagen, L. K., Zemke, J., Zhang, D., & Gray, G. C. (2018). The continual threat of influenza virus infections at the human–animal interface. Evolution, Medicine, and Public Health, 2018(1), 192–198. https://doi.org/10.1093/emph/eoy013

Abstract: This year, in 2018, we mark 100 years since the 1918 influenza pandemic. In the last 100 years, we have expanded our knowledge of public health and increased our ability to detect and prevent influenza; however, we still face challenges resulting from these continually evolving viruses. Today, it is clear that influenza viruses have multiple animal reservoirs (domestic and wild), making infection prevention in humans especially difficult to achieve. With this report, we summarize new knowledge regarding influenza A, B, C and D viruses and their control. We also introduce how a multi-disciplinary One Health approach is necessary to mitigate these threats. 1. Bailey ES, Choi JY, Fieldhouse JK, Borkenhagen LK,

Huijben, S., Chan, B. H., Nelson, W. A., & Read, A. F. (2018). The impact of within-host ecology on the fitness of a drug-resistant parasite. Evolution, Medicine, and Public Health, 2018(1), 127-137.

Background and objectives: The rate of evolution of drug resistance depends on the fitness of resistant pathogens. The fitness of resistant pathogens is reduced by competition with sensitive pathogens in untreated hosts and so enhanced by competitive release in drug-treated hosts. We set out to estimate the magnitude of those effects on a variety of fitness measures, hypothesizing that competitive suppression and competitive release would have larger impacts when resistance was rarer to begin with. Methodology: We infected mice with varying densities of drug-resistant Plasmodium chabaudi malaria parasites in a fixed density of drug-sensitive parasites and followed infection dynamics using strain-specific quantitative PCR. Results: Competition with susceptible parasites reduced the absolute fitness of resistant parasites by 50–100%. Drug treatment increased the absolute fitness from 2- to >10 000-fold. The ecological context and choice of fitness measure was responsible for the wide variation in those estimates. Initial population growth rates poorly predicted parasite abundance and transmission probabilities. Conclusions and implications: (i) The sensitivity of estimates of pathogen fitness to ecological context and choice of fitness measure make it difficult to derive field-relevant estimates of the fitness costs and benefits of resistance from experimental settings. (ii) Competitive suppression can be a key force preventing resistance from emerging when it is rare, as it is when it first arises. (iii) Drug treatment profoundly affects the fitness of resistance. Resistance evolution could be slowed by developing drug use policies that consider in-host competition.

A most intriguing  article by Moises Velasquez-Manoff showed up in this week’s NY Times magazine. It starts with the new data showing that meat allergy can be precipitated by a tick bite. Alpha-gal (Galactose-alpha-1,3,-galactose) is present in other mammals but not humans. So, if a tick transmits the antigen, we can become allergic to meat.

But the article goes much further using smooth prose to integrate findings from many studies, also asking why mean allergies are becoming more common now. Is it more tick bites?  Or changed microbiomes?   Wonderful science writing about evolutionary medicine.

What the Mystery of the Tick-Borne Meat Allergy Could Reveal 
By Moises Velasquez-Manoff   NY Times July 23, 2018
One spring evening in 2016, Lee Niegelsky’s underarm began to itch. An investment manager, he was doing housework around his condo, and he thought he’d been bitten by a chigger. But within 15 minutes, hives had erupted all over his body. He responded with what he calls a “typical man reaction” — if the hives didn’t clear up by the next day, he would have them checked. Fifteen minutes later, the itch had become unbearable. He needed help right away. …Read the article at NYTimes.com