peh forum_29sept2016

4 years on, what do we know?

Ian M. Mackay, PhDPublic and Environmental Health – Virology

Forensic & Scientific Services | Health Support QueenslandDepartment of Health

& Associate Professor, The University of [email protected]

Opinions expressed here are my own; references available upon request

Middle East respiratory syndrome (MERS)

2PEH FORUM 29SEPT2016

Middle East respiratory syndrome coronavirus (MERS-CoV)

3

Kingdom of Saudi Arabia (KSA) is the hot zone•1st report of novel CoV– 20th Sept 2012•Most cases are from human-to-human transmission

• respiratory disease caused by a respiratory virus• weak & sporadic transmission between humans• acquired mostly from humans in healthcare settings

•Seroprevalence: 0.15% • 2013, 15 of 10,009 adults, KSA• highest seroprevalence among shepherds and slaughterhouse

workers

PEH FORUM 29SEPT2016

The hot zone is hot & subtropical


Hajj: “The massest of Mass gatherings”-Helen Branswell


The MERS coronavirus (MERS-CoV)•Enveloped, 30,000nt (+) RNA virus•4 structural ( ), 16 NS proteins; recombination

•Little sign of adapting to humans so far •Single serotype•Uses dipeptidyl peptidase 4 (DPP4; LRT>URT) for entry


Hu et al. Virol J .2015 12:221

Ancestors of MERS-CoV•Bats

• focus of first papers• many recent CoVs discovered• likely ancestor found

•Conspecific virus • Neoromicia (Pipistrellus)

capensis• South Africa• “NeoCoV”



MERS-CoV in bats•1 rtPCR amplicon

• 1 sample• 1 bat • 1 species (Taphozous perforatus)• 1,003 samples Oct 2012 / April 2013• not convincing

10

Why camels?•Important animals – much contact

• Arabian peninsula

•Mild camel disease – common cold• 1st MERS case did own camels• juvenile camels more often virus positive• high level of virus in camel secretions• Camel herds can be 100% seropositive• Camel-to-human infection reported

•No other animal found to host virus• alpaca with antibody



Camel virus > human spillover•Same virus in camels & humans•225 genomes

• 3 genetic groupings

•Camel & human variants• interspersed• 96.5-100% nt identity


MERS-CoV: A distinct virus


“Contact?”

Example of rare contact


More likely forms of contact


Persistence •MERS-CoV is stable on surfaces

• more stable than influenza A(H1N1) virus in aerosol (10min) & on hard surfaces

•MERS-CoV RNA can shed for >1 month• detected from a HCW for 42 days


The disease, MERS•Incubation period 2-16 days (median 4/5 days)•Comorbidity (e.g. 87%) & cough (e.g. 100%) common

• asymptomatic• acute URT illness incl. fever, headache, myalgia• progressive pneumonitis, respiratory failure, septic shock,

multi-organ failure•20% -74% (ICU) mortality (median: 12 days onset>death)

• SARS-10%


Treatment•No antivirals available•Passive immunotherapy (antibody) - clinical effect?

• infrequent donors (2%)• antibody titres low/short-lived in convalescent human sera

•Vaccines• a range in the pipeline for humans and animals

•Supportive care



MERS in humans is about humans with MERS

?

20

MERS: cases driven by habits and errors?


South Korea outbreak, May-Dec 2015•186 cases, 38 fatalities (20%), 4 waves of infection•Biggest outbreak outside KSA

• >16,000 people quarantined•No sustained h2h transmission

• no community outbreaks•1/186 case travelled to China•7.4 day incubation period (6.2 > 7.7 > 7.9 by generation)


South Korea outbreak, May-Dec 2015•1 patient responsible for 81 cases

• visited 4 hospitals• coughed in the open• walked through ER to public toilet

•Receptor binding domain mutant in 13/14 variants• reduced receptor affinity• not every virus mutates according to a Hollywood script


South Korea outbreak, May-Dec 2015•Lower proportion fatal •20% compared to 41% in KSA

• due to the mutation?• lower % underlying comorbidities in general community


South Korea outbreak washup•Quarantine was initially limited

• casual contacts needed to be included as well as close contacts•4 beds/room – cases initially not isolated

• overcrowding

•Family members were responsible for some hospital care• prolonged, close contact

•Patients easily moved between hospitals• hospitals didn’t share past disease history on patients


South Korea outbreak, May-Dec 2015


1-Choi. Yonsei Med J. 2015 56(5):1174-76

Issues to address large healthcare outbreaks of MERS

•Identify symptomatic patients early; test & re-test•Strong contact tracing, monitoring and quarantine•Strong infection, prevention and control measures

• PPE – selection, use, donning/doffing, disposal• distance between beds• be aware of aerosol generating procedures• cleaning & disinfection• treat / manage patients in isolation

•Communicate with public to build/maintain trust


28

Cases are rare but travel is not

•Control MERS in the hotzone, avoid global spread


Stop hospital outbreaks, reduce MERS cases

•Humans create circumstances for super-spreading events



Thankyou

peh forum_29sept2016

Documents