Ebolavirus disease (EVD) outbreaks in West Africa Summary

Transcription

Ebolavirus disease (EVD) outbreaks in West Africa Summary
Ebolavirus disease (EVD) outbreaks in
West Africa
Important information for general practitioners
11 August 2014
Summary
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The largest outbreak of Ebolavirus disease (EVD)1 ever reported is continuing in Guinea,
Liberia and Sierra Leone in West Africa, with probable and suspected cases also reported
from Nigeria.
Regular updates are available from the World Health Organization (WHO) website
(http://www.who.int/csr/don/en/)
As of 6 August 2014, there were 1,779 clinically-compatible cases, of which 1,134 have been
laboratory confirmed, and 961 have died (case fatality rate 54%).
The risk of infection is extremely low unless there has been direct exposure to the bodily
fluids of an infected person (including unprotected sexual contact with confirmed cases up
to seven weeks after they have recovered) or animal (alive or dead).
In patients with clinically-compatible symptoms as per the Communicable Diseases Network
Australia (CDNA) case definition (see section below ‘What are the symptoms and how do I manage
a suspected case?’) with a history of travel or residence in affected areas (see map) in the 21 days
prior to symptom onset, and contact with known confirmed or probable cases in the 21 days before
illness onset, the following is recommended:
1. The patient should be placed in a single room if available and standard and transmissionbased precautions implemented (contact and droplet), including the use of personal
protective equipment (PPE).
The relevant state/territory public health unit/communicable diseases branch should be notified
promptly of any suspected (and probable or confirmed) cases in order to discuss patient referral
and coordinate management of contacts.
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The disease has previously been called Ebola Haemorrhagic Fever, but not all cases are haemorrhagic, and
the WHO has begun referring to it as EVD.
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Map: Areas of Guinea, Liberia and Sierra Leone affected by EVD as of 7 August 2014 (from the CDC
website http://www.cdc.gov/vhf/ebola/resources/distribution-map-guinea-outbreak.html,
accessed 11 August 2014).
What are the symptoms and how do I manage a suspected case?
The likelihood that a febrile illness in a returned traveller is due to EVD is very low. However GPs
should be aware of the possibility of EVD in patients who meet the suspected case definition. GPs
should discuss the presentation of febrile illness in a returned traveller from an affected area with
an infectious disease physician as soon as possible.
The onset of symptoms is sudden and includes a flu-like illness, fever, myalgia, fatigue, and
headache. The next stage may include symptoms that are gastrointestinal (vomiting, diarrhoea),
neurological (headaches, confusion), vascular, cutaneous (maculopapular rash), respiratory (sore
throat, cough) and can include prostration. After one week, cases may develop a septic shock-like
syndrome, and progress to multi-organ failure, sometimes accompanied by profuse internal and
external bleeding. The case-fatality rate (CFR) for Zaire strain of EVD cases is estimated to be
between 50% and 90%, while for other species, the CFR may be lower.
The suspected case definition requires clinical and epidemiological evidence:
Clinical evidence
A compatible clinical illness as determined by an infectious disease physician. Clinical evidence,
which includes fever of greater than 38 degrees Celsius, and additional symptoms such as
severe headache, muscle pain, vomiting, diarrhoea, abdominal pain, or unexplained
haemorrhage;
AND
Epidemiological evidence
Epidemiologic risk factors within the past 21 days before the onset of symptoms, such as
contact with blood or other body fluids of a patient known to have or suspected to have EVD;
residence in—or travel to—an area where EVD transmission is active; or direct handling of bats
or primates from disease-endemic areas.*
* Affected areas should currently be considered to be Guinea, Liberia, Nigeria and Sierra Leone, but
travel to neighbouring countries in West Africa (Mali, Cote d’Ivoire, Guinea-Bissau, Senegal (Map))
should also be considered where there is strong clinical suspicion. Further, filoviruses are endemic
in sub-Saharan Africa. It should be noted that the risk of infection is extremely low even in persons
with a compatible travel history, unless there has been direct exposure to the bodily fluids of an
infected person (including unprotected sexual contact with confirmed cases up to seven weeks
after they have recovered) or animal (alive or dead).
GPs must notify a suspected case immediately to their state/territory communicable disease
branch/centre to discuss patient referral and management of contacts (see “Who do I contact if I
have a suspected case?” for contact information).
How do I test for EVD?
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Testing for EVD is not normally conducted in a general practice setting and patients should
be notified and referred as per the previous section.
If, following discussion with public health authorities and infectious disease physicians, it is
decided that the patient does not require testing for EVD, the patient should be managed as
per usual practice.
Are health workers at risk from EVD?
Caring for ill relatives is a known risk factor for infection, and healthcare workers, particularly those
in resource poor settings with inadequate infection control are also at risk.
What are the recommended isolation and PPE recommendations for
patients in general practice?
Infection control recommendations in this document for suspected cases aim to provide the
highest level of protection for health care workers, given the current state of knowledge. In
patients with compatible symptoms and exposure history, GPs should follow standard precautions
for infection control, and to minimise the risk of spread of EVD, contact and droplet precautions
(transmission based precautions) are used in addition to standard precautions.
The Royal Australasian College of General practitioners (RACGP) provides infection control
standards for office-based practice (http://www.racgp.org.au/yourpractice/standards/infectioncontrol/).
Transmission based precautions (previously known as additional precautions) are used where
patients have suspected or known infectious conditions, such as EVD:
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Contact precautions are used to prevent both direct and indirect contact transmission.
Contact precautions involve the use of gloves, gowns and social distancing (i.e. move patient
from general waiting area where possible). Gloves need to be worn for all manual contact
with patients, associated equipment and the immediate environment. A water impermeable
apron or gown needs to be worn if clothing could be in substantial contact with the patient
or their immediate environment.
Droplet precautions are used to minimise transmission of droplets generated by coughing,
sneezing and talking. Droplet precautions involve the use of surgical masks (worn by staff),
protective eyewear (goggles or face shield) and social distancing. Patients should be asked
to observe respiratory (cough) hygiene.
Transmission-based precautions are further detailed in NHMRC: Australian Guidelines for the
Prevention and Control of Infection in Healthcare - 2010 - External Link (particularly section B2.3).
Pre-travel advice for travellers
The WHO does not recommend that any travel restrictions are applied with respect to this event.
GPs should emphasise the general low risk, but that travellers should avoid direct exposure to the
bodily fluids of an infected person or animal (alive or dead), including unprotected sexual contact
with patients up to seven weeks after they have recovered. Further information is provided by the
the Department of Foreign Affairs and Trade Smartraveller Bulletin available from the DFAT website
(http://smartraveller.gov.au/zw-cgi/view/TravelBulletins/Ebola) and the European Centres for
Disease Control (ECDC) Ebola travel Advice, available from the ECDC website
(http://www.ecdc.europa.eu/en/publications/_layouts/forms/Publication_DispForm.aspx?List=4f5
5ad51-4aed-4d32-b960-af70113dbb90&ID=1075).
Background information
Ebolaviruses
EVD is caused by an Ebolavirus. Ebolaviruses are part of the family Filoviridae. Fruit bats of the
Pteropodidae family are considered to be a likely natural host of the Ebolavirus, with outbreaks
amongst other species such as chimpanzees, gorillas, monkeys, forest antelope from time to time.
Five species of Ebolavirus have been identified, namely Zaire, Sudan, Reston, Tai Forest and
Bundibugyo, from samples collected during humans and non-human primates outbreaks since the
first outbreak in the Democratic Republic of the Congo.
Transmission
Ebola is introduced into the human population through close contact with the blood, secretions,
organs or other bodily fluids of infected animals (often therefore through hunting or preparation of
"bushmeat"). Ebola virus then spreads through person-to-person transmission via contact with the
blood, secretions, organs or other bodily fluids of infected people, and indirect contact with
environments contaminated with such fluid, including in healthcare settings. The risk for infection
in healthcare settings can be significantly reduced through the appropriate use of infection control
precautions and adequate barrier procedures. Transmission through sexual contact may occur up
to seven weeks after clinical recovery. Airborne transmission, as occurs for measles or smallpox,
has never been documented. Simple physical contact with a sick person appears not to be sufficient
for contracting EVD. Transmission through heavily contaminated fomites is apparently possible.
Traditional burial ceremonies in affected areas of Africa are a known high risk activity for
transmission.
Symptoms and incubation period
The onset of symptoms is sudden and includes fever, muscle aches, weakness, headache and sore
throat. The next stage is characterised by vomiting, diarrhoea, rash and malfunction of liver and
kidneys. Some cases present with profuse internal and external bleeding and progress to multiorgan failure. The case-fatality ratio for the Zaire strain of Ebolavirus is estimated to be between
50% and 90%. The incubation period varies from 2 to 21 days.
Treatment
There are no specific prophylactic (vaccine) or therapeutic (antiviral drugs) options available to
treat human infections, and care is largely supportive.
EVD is a quarantinable disease in Australia.
Situation update
See the WHO website (http://www.who.int/csr/don/en/) for the latest information
Guinea
As of 6 August 2014, the Ministry of Health of Guinea had reported a total of 495 clinically
compatible cases, including 367 deaths (case-fatality rate, CFR 73%), of which 355 tested positive
by PCR.
Liberia
As of 6 August 2014, the Ministry of Health and Social Welfare (MOHSW) of Liberia had reported a
total of 554 clinical cases of EVD, including 294 deaths (CFR 53%) of which 148 cases tested positive
by PCR.
Nigeria
As of 6 August 2014, the Ministry of Health in Nigeria had reported 13 clinical cases of EVD (seven
probable and six suspected), including two deaths. None of the cases have been confirmed.
Sierra Leone
As of 6 August 2014, the Ministry of Health and Sanitation of Sierra Leone had reported a total of
717 clinically-compatible cases including 298 deaths (CFR 42%), of which 631 tested positive by
PCR.
Further advice
Surveillance case definition for confirmed and probable cases, available from the Department of
Health website (http://www.health.gov.au/internet/main/publishing.nsf/Content/cda-surveilnndss-casedefs-cd_vhf.htm)
WHO situation updates http://www.who.int/csr/disease/ebola/en/
WHO Fact Sheet on Ebolavirus disease http://www.who.int/mediacentre/factsheets/fs103/en/
WHO AFRO updates http://www.afro.who.int/en/clusters-a-programmes/dpc/epidemic-apandemic-alert-and-response/outbreak-news.html
Reporting
The GP must notify a suspected case immediately to their state/territory communicable disease
branch/centre to discuss referral (see “Who do I contact if I have a suspected case?” for contact
information).
Where there is clinical need for an ambulance, this should precede contact with the state/territory
communicable disease branch/centre.
Advice for contacts of cases
Contacts of cases should be directed to your state/territory communicable disease branch/centre
for advice.
Who do I contact if I have a suspected case?
Contact your state/territory communicable disease branch/centre.
ACT
(02) 6205 2155
NSW
1300 066 055
Contact details for the public health offices in NSW Area Health Service Areas
(www0.health.nsw.gov.au/publichealth/Infectious/phus.asp)
NT
(08) 8922 8044
Queensland
13 432 584
Contact details for the public health offices in QLD Area
(www.health.qld.gov.au/cdcg/contacts.asp)
SA
1300 232 272
Tasmania
1800 671 738
Victoria
1300 651 160
WA
(08) 9388 4801 After hours (08) 9328 0553
Contact details for the public health offices in WA
(www.public.health.wa.gov.au/3/280/2/contact_details_for_regional_population__public_he.pm)

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