Thursday, July 06, 2017

WHO: Update & Risk Assessment On Meningococcal Outbreak in Liberia

















#12,600

In late April the WHO Held A Press Conference On A Cluster Of Unexplained Deaths In Liberia, which appeared connected to attendance of a funeral.  While a scenario eerily  similar to what we saw in Liberia during their Ebola outbreak in 2014, Ebola was quickly ruled out.
For nearly two weeks an unidentified toxin was suspected, but in CIDRAP: Meningitis Suspected In Liberian Outbreak, we learned that the CDC's lab in the United States had identified Neisseria meningitidis serotype C among samples from seven of the fatal cases.
A monovalent serotype A vaccine (MenAfriVac, Serum Institute of India) came into widespread use in Africa's meningitis belt in 2010, and since then the yearly incidence of meningitis has declined.
But as serotype A has diminished, serotype C has begun to flourish in the region.

Today the WHO has published lengthy update on that outbreak, including a risk assessment on the possibility of seeing future outbreaks.

Meningococcal septicaemia associated with attending a funeral – Liberia

Disease outbreak news
6 July 2017

This is an update to the Disease Outbreak News “Unexplained cluster of deaths – Liberia” published on 5 May 2017 and update published on 10 May 2017.

On 25 April 2017, the Ministry of Health (MoH) of Liberia notified WHO and partners of a cluster of sudden deaths of unknown aetiology in Sinoe County. The event started on 23 April 2017, when an 11-year-old female had been admitted to hospital presenting with diarrhoea, vomiting, and mental confusion after attending the funeral of a religious leader on 22 April 2017. The child died within one hour of admission.

Between 23 April and 7 May, a total of 31 cases including 13 deaths, and one case with neurological sequelae of an unknown disease associated with attending a funeral were reported from three counties (Sinoe, Grand Bassa, and Montserrado). The majority of cases did not present with fever, but did present with abdominal pain, diarrhoea, vomiting, and mental confusion. Some patients presented with purpura and/ or petechiae. Most of the cases were related to each other either socially, through family or school. All but two cases attended the funeral, who were subsequently identified as contacts of the index case.

On 8 May 2017, MoH informed partners and the public that specimens taken from patients tested positive for Neisseria meningitidis serotype C at the United States Centers for Disease Control and Prevention (CDC). The outbreak was therefore classified as a meningococcal disease outbreak. A total of 14 cases out of 31 cases were later confirmed with presence of Neisseria meningitidis C by PCR in clinical specimens conducted at the National Reference Laboratory in Liberia or clinically diagnosed due to the presence of purpura fulminans.
Laboratory results were further confirmed by the National Institute for Communicable Diseases (NICD) and the National Institute of Occupational Health (NIOH) in Johannesburg, South Africa, in addition to serological results of three cases that were tested at Institute Pasteur in France. The temporal characteristics of this outbreak are unusual raising the hypothesis of the presence of a co-factor.

Additionally, on 8 May 2017, the MoH informed partners and the public that toxicological investigations conducted by CDC on urine samples from three cases did not suggest that intoxication was the cause of the outbreak. The samples were tested for pesticide metabolites and toxic metals.

On 20 June 2017, the MoH was notified that results of toxicological investigations carried out at the Center for Analytical Chemistry in Vienna, Austria, on food samples, water and a soft drink that were consumed during the funeral, were not suggestive of intoxication. The samples were tested for more than 600 fungal and bacterial toxins and these were either not detected or were within regulatory limits.


Public health response

The MoH supported by the WHO, CDC, Africa Field Epidemiology Network (AFENET), and other partners started on-site investigations one day after the alert. No disease was identified at the start of the outbreak and Ebola virus disease (EVD) was ruled out within 24 hours of the alert.

The National Public Health Institute of Liberia was activated to lead the response. WHO, CDC, UNICEF, and MSF reinforced the field response, and international coordination and information sharing was supported though the Global Outbreak Alert and Response Network (GOARN). The following response activities were implemented:

  • Most of the cases from Sinoe were managed in the local hospital in Greenville, the capital of Sinoe County and received treatment as per EVD protocol.
  • Infection, prevention, and control measures were implemented in the local hospital.
  • Active case searching was conducted and identified attendees of the funeral and close contacts of the cases were followed up for 21 days.
  • Autopsies were conducted on two patients.
  • Approximately 70 specimens (58 clinical specimens and 12 food samples) were collected for laboratory testing and sent to the national reference laboratory in Margibi County, the United States, France, South Africa, and Austria.
  • Chemoprophylaxis was distributed to all attendees, contacts of the cases, health workers, and burial personnel.
  • A meningitis C vaccination strategy was discussed but not implemented due to the lack of secondary transmission.
  • Social mobilization was implemented with the support of UNICEF.
WHO risk assessment

In the absence of clear understanding of the epidemiology of this outbreak , the risk of recurrence cannot be excluded. However, based on current understanding of the epidemiology of meningococcal disease, the risk is considered low.

The efficient and timely implementation of the response to this event is a result of the expertise developed in Liberia following the large outbreak of EVD in 2014. This led to the quick identification of the event, testing and ruling out EVD as the cause of the outbreak, identification of contacts and their follow-up and the collaboration of the country with partners to perform laboratory testing of human and environmental specimens, which led to the identification of the cause of the disease.
WHO advice

WHO does not recommend any restriction on travel and trade to Liberia on the basis of the information available on the current event.

WHO recommends the inclusion of meningococcal septicemia in routine surveillance in Liberia as an epidemic prone disease together with meningitis due to Neisseria meningitidis.

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