Saturday, July 6, 2013

WHO: #MERS #Coronavirus - Guidelines For Investigation of Cases - July 5, 2013

[This will be located on the right side-bar, under "Coronavirus MERS-Cov" for future reference]

1. Introduction   
Coronaviruses are a large family of viruses that can cause a range of illnesses in humans, from the common cold to severe acute respiratory syndrome (SARS).  These viruses also cause disease in a wide variety of animal species.
In  late  2012,  a  novel  coronavirus  that  had  not  previously  been  seen  in  humans  was  identified  for  the  first   time  in  a  resident  of  the  Middle  East.  The  virus,  now  known  as  the  Middle  East  Respiratory  Syndrome   Coronavirus  (MERS-­‐CoV),1  has  caused  more  than  50  laboratory-­‐confirmed  cases  of  human  infection.   Thus  far,  all  patients  infected  with  MERS-­‐CoV  have  had  a  direct  or  indirect  link  to  the  Middle  East,   however,  local  non-­‐sustained  human-­‐to-­‐human  transmission  has  occurred  in  other  countries,  in  people   who  had  recently  travelled  to  the  Middle  East. 
All  MERS-­‐CoV  patients  have  primarily  had  respiratory  disease,  although  a  number  of  secondary   complications  have  also  been  reported,  including  acute  renal  failure,  multi-­‐organ  failure,  acute   respiratory  distress  syndrome  (ARDS),  and  consumptive  coagulopathy.  In  addition,  many  patients  have   also  reported  gastrointestinal  symptoms,  including  diarrhoea.  More  than  half  of  infected  patients  have   died.  The  majority  has  had  at  least  one  comorbid  condition,  but  many  have  also  been  in  previous  good   health.  A  small  number  of  cases  had  had  co-­‐infection  with  other  viruses  including  influenza  A,   parainfluenza,  herpes  simplex,  and  pneumococcus.  As  of  6  June,  the  median  age  of  reported  laboratory-­‐ confirmed  cases  is  56  years  (Range  2–94  years)  and  majority  (72%)  are  males.2  A  current  update  of  the   cases  can  be  found  at  WHO’s  Coronavirus  website. 

The  MERS-­‐CoV  virus  is  thought  to  be  an  animal  virus  that  has  sporadically  resulted  in  human  infections,   with  subsequent  limited  transmission  between  humans.  The  evidence  for  the  animal  origin  of  the  virus   is  circumstantial.  Nevertheless,  the  alternative  explanation  to  explain  the  sporadic  appearance  of  severe   human  cases  with  long  periods  of  time  between  them,  and  the  wide  geographical  area  over  which  the   virus  was  apparently  distributed,  is  unrecognized  ongoing  transmission  in  people.  Surveillance  efforts   since  the  discovery  of  the  virus  and  retrospective  testing  of  stored  respiratory  specimens  suggest  this  is   not  the  case.  
The  virus  has  been  demonstrated  to  grow  well  in  cell  lines  that  in  the  past  have  commonly  been  used  for   diagnostic  viral  cultures.  Finally,  early  comparisons  with  other  known  coronaviruses  suggest  a  genetic   similarity  to  viruses  previously  described  in  bats.  However,  even  if  an  animal  reservoir  is  identified,  it  is   critical  to  identify  the  types  of  exposures  that  result  in  infection  and  the  mode  of  transmission.  It  is  unlikely  that  transmission  occurs  directly  from  animals  to  humans  and  the  route  of  transmission  may  be   complex  requiring  intermediary  hosts,  or  through  contaminated  food  or  drink.  
A  considerable  proportion  of  MERS-­‐CoV  cases  have  been  part  of  clusters  in  which  limited  non-­‐sustained   human-­‐to-­‐human  transmission  has  occurred.  Human-­‐to-­‐human  transmission  has  occurred  in  health  care   settings,  among  close  family  contacts,  and  in  the  work  place.  Sustained  transmission  in  the  community   beyond  these  clusters  has  not  been  observed  and  would  represent  a  major  change  in  the  epidemiology   of  MERS-­‐CoV.  
A  number  of  unanswered  questions  remain  on  the  virus  reservoir,  how  seemingly  sporadic  infections  are   being  acquired,  the  mode  of  transmission  from  animals  to  humans  and  between  humans,  the  clinical   spectrum  of  infection,  and  the  incubation  period.  
2. Purpose and scope of the document   
This  document  provides  a  standardized  approach  for  public  health  authorities  and  investigators  at  all   levels  to  plan  for  and  conduct  investigations  around  confirmed  and  probable  cases  of  MERS-­‐CoV   infection.  It  should  be  read  in  conjunction  with  other  detailed  guidance  referenced  throughout  the  text,   such  as  current  laboratory  testing  guidelines  and  study  protocols.  It  will  be  updated  as  necessary  to   reflect  increased  understanding  of  MERS-­‐CoV  transmission  and  control.   

Most  of  the  advice  given  in  this  document  will  apply  primarily  to  countries  in  which  infection  is   presumed  to  have  originated  from  an  animal  or  environmental  source,  and  the  exposures  that  result  in   infection  remain  the  critical  questions.  In  countries  that  have  secondary  transmission  related  to   imported  cases,  however,  the  recommendations  for  finding  secondary  cases  and  observing  subsequent   community  transmission  are  still  valid,  though  on  a  more  limited  scale.  Similarly,  the  case-­‐control  study   recommended  as  a  high  priority  in  the  second  part  of  the  document  is  not  applicable  to  countries  with   imported  cases,  since  the  purpose  of  the  study  is  to  uncover  the  non-­‐human  exposures  leading  to   infection.  However,  other  studies  on  health  care  facility  transmission  and  clinical  management  are  still   recommended.  
As  with  nearly  all  recent  emerging  novel  pathogens,  most  early  cases  of  MERS-­‐CoV  infection  will  likely   be  detected  by  astute  clinicians  rather  than  through  established  indicator  or  sentinel  surveillance   systems.  Therefore,  the  most  effective  tool  in  detection  will  be  awareness  among  the  health  care   providers.  An  effective  detection  system  will  also  need  to  include  a  readily  available  channel  by  which clinicians  can  report  suspect  cases,  and  an  effective  response  mechanism.  The  Western  Pacific  Regional   Office  of  WHO  (WPRO)  has  published  a  guide  for  event  surveillance.3  

This  document  addresses  two  general  categories  of  activities  that  need  to  be  undertaken  to  deal  with   newly  identified  cases.  The  first  involves  further  case  finding,  case  description,  and  surveillance   enhancements  in  the  area  where  the  case  is  discovered.  The  primary  purpose  of  these  activities  is  to   fully  describe  the  epidemiology  of  the  cases,  identify  and  monitor  close  contacts  of  the  cases  and   determine  the  extent  of  spread  of  the  virus  in  the  area  (sections  3  and  4).  The  second  group  of  activities   is  a  number  of  discrete  studies  aimed  at  answering  critical  questions  related  to  MERS-­‐CoV  (section  5).

 [Continued, see Document link below]

2  WHO  Coronavirus  website:

Document Link:

No comments: