Avian Flu Diary: Survivalitiy

Photo Credit Wikipedia

# 8445

Although limited human-to-human transmission of the MERS Coronavirus has been established, and there’s pretty good evidence to suggest repeated introduction of the virus to humans via camels (see CIDRAP NEWS report WHO sees camels as MERS source, but route uncertain), the full ecology of this virus remains murky at best.

Today we’ve a letter that appears in the CDC’s EID Journal that looks at whether unpasteurized milk could serve as a possible source of human infection.

Previously, in Eurosurveillance: Environmental Stability Of MERS-CoV, we looked at research that found - under the right conditions - the MERS virus could remain viable outside a living host for a prolonged period of time. Among their findings:

While the Influenza A virus became non-viable on steel and plastic surfaces in less than 4 hours for all testing environments, the MERS virus survived 48 hours in the 20°C – 40% RH environment. Survival of the coronavirus at 30°C – 30% RH was 24 hours, and 8 hours at 30°C – 80% RH.
As an aerosol, the MERS virus remained very stable at 20°C – 40% RH, while its viability decreased (89% – comparable to the Influenza A virus) at 20°C – 70% RH.

In today’s report researchers inoculated various types of milk products (camel, goat, cow, etc.) and DMEM (a cell culture media) with MERS-CoV strain Jordan-N3/2012, stored multiple samples at 4°C or 22°C, and then tested their infectious disease titers at 0, 8, 24, 48, 72 hours post dilution.

Their results?

At 0–72 hpd, virus titers decreased significantly only in goat milk (p = 0.0139, 1-tailed paired t test) and DMEM (p = 0.0311) but not in dromedary camel milk (p = 0.1414) or cow milk (p = 0.2895). Samples stored at 22°C showed a greater loss of infectivity than did samples stored at 4°C.

Making unpasteurized milk at least a plausible medium for carriage of the MERS virus or its transmission to humans.

I’ve excerpted a few paragraphs, but you’ll want to read the entire letter for details on materials and methods used.

Volume 20, Number 7—July 2014

Letter

Stability of Middle East Respiratory Syndrome Coronavirus in Milk

van Doremalen N, Bushmaker T, Karesh WB, Munster VJ.

To the Editor: Middle East respiratory syndrome coronavirus (MERS-CoV) was first diagnosed in humans in 2012. Human-to-human transmission of MERS-CoV has been limited, and the transmission route is still unclear. On the basis of epidemiologic studies, involvement of an animal host has been suggested (1). Dromedary camels have been identified as a possible intermediate host on the basis of MERS-CoV antibodies and detection of MERS-CoV viral RNA in respiratory swab samples (1–3). Furthermore, MERS-CoV genome sequences obtained from dromedary camels clustered with MERS-CoV sequences obtained from humans linked to the same farm (2). Nonetheless, most persons with MERS-CoV did not report any direct contact with dromedary camels; therefore, how MERS-CoV zoonotic transmission occurs is unclear. MERS-CoV replicates in cell lines originating from a wide variety of different hosts, which suggests the potential for a broader reservoir species range then currently recognized (4). However, unlike in dromedary camels, no serologic evidence pointing toward MERS-CoV infection has been found in goats, sheep, and cows (1).

Contamination of dairy products has been associated with transmission of bacteria and viruses. Shedding of infectious tick-borne encephalitis virus in milk was detected after experimental infection of goats, and the consumption of raw milk has been associated with tick-borne encephalitis virus clusters (5). Similarly, cattle can be infected with foot-and-mouth disease through consumption of raw contaminated milk (6).

<SNIP>

Residents of the Arabian Peninsula commonly drink unpasteurized milk. Our results show that MERS-CoV, when introduced into milk, can survive for prolonged periods. Further study is needed to determine whether MERS-CoV is excreted into the milk of infected dromedary camels and, if so, whether handling or consuming contaminated milk is associated with MERS-CoV infection.

(Continue . . . )

V-Fib Lead II – Credit Glenlarson Wikipedia Commons

# 6874

Some new studies out today indicate that longer CPR on patients who suffer an in-hospital cardiac arrest can result in improved survival rates.

In-hospital cardiac arrests are more likely to survive than out-of-hospital arrests simply because they are generally `witnessed arrests’ so CPR is initiated quicker, and the requisite `crash cart’ and medical personnel trained to use them are readily available.

Still, survival rates for in-hospital cardiac arrests are sobering, with a recent study (Trends in Survival after In-Hospital Cardiac Arrest) published in the NEJM finding that risk-adjusted rates of survival to discharge increased from 13.7% in 2000 to 22.3% in 2009.

This improvement also came with a reduction in neurological impairment in the survivors as well.

Another study, on a smaller cohort of pediatric (<18 years) patients experiencing in-hospital cardiac arrest found a tripling of survival rates between 2000 and 2009 (see Survival Trends in Pediatric In-Hospital Cardiac Arrests: An Analysis From Get With The Guidelines-Resuscitation Girotra S, Spertus JA, Li Y, et al.), again without higher rates of neurological disability among survivors.

One of the trends cited in both of these studies has been a dramatic increase in cardiac arrests due to non-shockable arrhythmias such as asystole (flat line) and PEA (Pulseless Electrical Activity) – what we used to call back in the stone age of EMS, electromechanical dissociation.

Neither of which respond to simple defibrillation.

Despite this trend, survivability of in-hospital cardiac arrests is improving (see Survivability Of Non-Shockable Rhythms With New CPR Guidelines).

Today, we look at a couple of studies that indicate that longer duration CPR for in-hospital arrests can result in better outcomes than previously believed. In the past, the belief has been that after 20 to 25 minutes, most resuscitation attempts become futile.

First a press release from Children's Hospital of Philadelphia (CHOP) describing these studies, then the links to the research.

Longer CPR extends survival in both children and adults

CHOP experts are co-authors of 2 large studies of outcomes after in-hospital cardiac arrest

Experts from The Children's Hospital of Philadelphia were among the leaders of two large national studies showing that extending CPR longer than previously thought useful saves lives in both children and adults. The research teams analyzed impact of duration of cardiopulmonary resuscitation in patients who suffered cardiac arrest while hospitalized.

"These findings about the duration of CPR are game-changing, and we hope these results will rapidly affect hospital practice," said Robert A. Berg, M.D., chief of Critical Care Medicine at The Children's Hospital of Philadelphia. Berg is the chair of the Scientific Advisory Board of the American Heart Association's Get With Guidelines-Resuscitation program (GWTG-R). That quality improvement program is the only national registry that tracks and analyzes resuscitation of patients after in-hospital cardiac arrests.

The investigators reported data from the GWTG-Resuscitation registry of CPR outcomes in thousands of North American hospital patients in two landmark studies—one in children, published today, the other in adults, published in October 2012.

Berg was a co-author of the pediatric study, appearing online today in Circulation, which analyzed hospital records of 3,419 children in the U.S. and Canada from 2000 through 2009. This study, whose first author was Renee I. Matos, M.D., M.P.H., a mentored young investigator, found that among children who suffered in-hospital cardiac arrest, more children than expected survived after prolonged CPR—defined as CPR lasting longer than 35 minutes. Of those children who survived prolonged CPR, over 60 percent had good neurologic outcomes.

The conventional thinking has been that CPR is futile after 20 minutes, but Berg said these results challenge that assumption.

In addition to Berg, two other co-authors are critical care and resuscitation science specialists at The Children's Hospital of Philadelphia: Vinay M. Nadkarni, M.D., and Peter A. Meaney, M.D., M.P.H.

Nadkarni noted that illness categories affected outcomes, with children hospitalized for cardiac surgery having better survival and neurological outcomes than children in all other patient groups.

The overall pediatric results paralleled those found in the adult study of 64,000 patients with in-hospital cardiac arrests between 2000 and 2008. Berg also was a co-author of that GWTG-R study, published in The Lancet on Oct. 27, and led by Brahmajee K. Nallamothu, M.P.H., M.D., of the University of Michigan. Patients at hospitals in the top quartile of median CPR duration (25 minutes), had a 12 percent higher chance of surviving cardiac arrest, compared to patients at hospitals in the bottom quartile of median CPR duration (16 minutes). Survivors of prolonged CPR had similar neurological outcomes to those who survived after shorter CPR efforts.

The American Heart Association and American Stroke Association designated the adult study as the top finding of the year in heart disease and stroke research in its annual list of major advances. Next steps for CPR researchers are to identify important risk and predictive factors that determine which patients may benefit most from prolonged CPR, and when CPR efforts have become futile. "Taken together, the adult and pediatric results present a clear and hopeful message: persisting longer with CPR can offer better results than previously believed possible," concluded Berg.

(Continue . . . )

The link to earlier Lancet report published online: 05 September 2012

Duration of resuscitation efforts and survival after in-hospital cardiac arrest: an observational study

Zachary D Goldberger MD, Paul S Chan MD, Prof Robert A Berg MD, Steven L Kronick MD, Colin R Cooke MD , Mingrui Lu MPH , Mousumi Banerjee PhD , Prof Rodney A Hayward MD, Prof Harlan M Krumholz MD , Dr Brahmajee K Nallamothu MD

And appearing today in Circulation.

Duration of Cardiopulmonary Resuscitation and Illness Category Impact Survival and Neurologic Outcomes for In-hospital Pediatric Cardiac Arrests

Renee I. Matos; R. Scott Watson; Vinay M. Nadkarni; Hsin-Hui Huang; Robert A. Berg; Peter A. Meaney; Christopher L. Carroll; Richard J. Berens; Amy Praestgaard; Lisa Weissfeld; Philip C. Spinella

Although these studies looked at in-hospital cardiac arrest, the use of AEDs (see Interactive Video: Using An AED For Sudden Cardiac Arrest (SCA)) in public venues, and the teaching of CPR Skills to the lay public, has had a substantial impact on the survivability of out-of-hospital cardiac arrests as well.

Luckily, today CPR is easier to do than ever.

Compression-only CPR is now the standard for laypeople, and so you don’t have to worry about doing mouth-to-mouth.

While it won’t take the place of an actual class, you can watch how it is done on in this brief instructional video from the American Heart Association.

A CPR class only takes a few hours, and it could end up helping you save the life of someone you love.

Of course, despite your best efforts, many SCA (sudden cardiac arrest) victims will not survive. But early and coordinated action taken by bystanders (calling 911, starting CPR, using AED if available) can substantially improve their chances.

For more on heart attacks, and CPR, you may wish to visit some of these earlier blogs.