Friday, 30 May 2014

MERS-CoV in the Netherlands...a detail analysis of cases

Red arrow indicates where Dutch 
MERS-CoV case sequences sit.
Click on tree to enlarge
This comes from a shiny newly released Eurosurveillance report from Dutch researchers. 

I've marked up my earlier tree to show where (based on partial 4,000nt fragment) the sequence from the Netherlands MERS-CoV positive cases (near identical) sits.

I've also charted Case 1's laboratory testing course, to show the variability of virus detection when a very thorough sampling and testing investigation is conducted. 

Viral RNA remained detectable in the blood for all days tested demonstrating viraemia (well, RNAaemia technically) from day-4 onwards. Urine was not positive but a faecal sample was, on day-5. The latter has implication for infection control in hospital settings whereby flushing toilets creating aerosols could be another contributor to spread.

Reverse transcription real-time polymerase chain reaction (RT-rtPCR) results are shown as positive (tall bars), negative (stumpy bars) or not tested (empty space) plotted against day of sampling.
Click on image to enlarge.

This is, as far as I'm aware, is only the second time human faeces or urine have been found to contain signs of MERS-CoV.

A throat swab was positive early on and then again after a 2-day period of negativity. This points to the possibility of shedding for over a week, when associated with cough. But given that this case was part of a tour group and they didn't all become symptomatic, MERS-CoV still didn't spread efficiently or result in disease very often (if it did spread), for whatever reason(s). Antibody testing would be interesting here too.

It would also be very interesting to know whether virus was being shed during the initial diarrhoea in Case 1, which predated his return to the Netherlands by about 8-days, or whether that was unrelated to the MERS-CoV infection. Perhaps testing faeces for gastrointestinal viruses would be useful, or interesting, here.