Sarah writes:

Dear TWiV Team,

I was so bummed about the weather–nary a mention. The weather from your various vantage points makes the podcast more vibrant/alive/real for me. I hope that other listeners who share my love of the weather will join in with gentle nudges to get it back into the show.

Thanks for your hard work in putting on this entertaining and informative look at the world with its viruses.

Sarah from Charlottesville, VA where it is 8 degC and partially cloudy at 19:39 Sunday Dec 23

Steve writes:

Hi Vincent,

Thought you might be interested in this snippet that turned up in my weekly‎ updates from our UK Health and Safety Inspectorate. I don’t remember there being a publicised national scare about it, and it doesn’t say what the hazard level was, but it’s sobering to read of emergency back up generators failing and even catching fire! :/

All the best,

Steve from Luton UK

(Where it’s cold, windy, and pouring with rain!)

“Hove Crown Court heard how, on Sunday 21 September 2014, mains power was lost at the site which includes high containment laboratory facilities required to safely handle high hazard pathogens that are a serious risk to human health and the environment.

Interserve Facilities Management Ltd was contracted to the site and was responsible for delivery of maintenance activities for many of the mechanical and electrical systems required for containment and control of high hazard biological agents in microbiological containment laboratories.

The court heard that when mains power was lost, of the twelve generators in place to supply emergency power to the site, two failed to operate and two started but subsequently failed in operation, one of which also caught fire.

The emergency escalation system was triggered, and the Fire and Rescue Service attended the site. Power was fully restored later that day.

As a result of the emergency generator failures, the court was told all power was lost to a number of high containment facilities for several hours, affecting the site’s safety systems.”

Samer writes:

Thank you for the discussion of MKPV in TWiV 520. It looks like the combination of metagenomic analysis and RNA in situ hybridization will help identify previously unrecognized viral infections in animals commonly used as model systems of disease or to understand basic biology. Below is a link to a preprint article that used a similar strategy to identify a novel picornavirus in zebrafish, an animal model growing in popularity.

I’d like to follow-up on comments made during “This old mouse” regarding the rederivation of mouse lines. Rederivation can be performed through a variety of procedures – Most commonly either via embryo transplant into the uterus of “clean” pseudopregnant recipient females (the way it was done in the MKPV paper) or via Caesarian section of a late term pregnant female with cross-fostering to a “clean” lactating female. In the latter case, this assumes the agent you are trying to eliminate is acquired at the time of or after birth and not vertically transmitted in utero. Embryos can be harvested at 0.5 days after confirmation of copulation plug in a mouse breeding cage  or developed via IVF. Embryos or sperm can be cryopreserved and banked for later use instead of maintaining a live animal breeding colony. As you mentioned during the discussion, Roedinger et al. described elimination of MKPV using embryo rederivation. I may be wrong, but MKPV may have been inadvertently eliminated from the vendor colonies because their breeding stock is routinely rederived into the clean breeding facility. I believe murine norovirus (MNV) was not found in many vendor colonies after it was discovered, because it was already eliminated during the rederivation process to eliminate other known viruses. However, the MNV remains common in academic settings because of less stringent biosecurity measures and the determination by some investigators that it doesn’t interfere with their research (or it’s too expensive and time consuming to do it). I wouldn’t be shocked if the same was true for MKPV. I agree with Vincent that it would be interesting to know the prevalence in wild mice. Parvoviruses are notoriously resistant to disinfection so carrying in to the barrier facility would be easy if facility biosecurity isn’t tight.


(/səˌmēr/, rhymes with “come here”, more commonly spelled Samir or Sameer)

Samer Jaber, DVM, DACLAM

Anthony writes:

“In issue 33, Mad [Magazine] published a partial table of the “Potrzebie System of Weights and Measures”, developed by 19-year-old Donald E. Knuth, later a famed computer scientist. According to Knuth, the basis of this new revolutionary system is the potrzebie, which equals the thickness of Mad issue 26, or 2.2633484517438173216473 mm”