No 1/2 - 2015

Infectious diseases 2014

The ebola virus outbreak in West Africa

2014 was marked by the epidemic caused by ebola virus disease in West Africa, EPI-NEWS 15/14, 33/14 and 51/14. According to the latest official figures, the epidemic that started early in 2014 counts more than 20,000 cases, including 8,000 deaths, but the real figure is expectedly higher.

The epidemic surpassed all previous ebola outbreaks with regard to the number of cases, geographic spread, media coverage and international efforts set in motion to control the outbreak. Despite these efforts, it will regrettably take time before the outbreak is controlled, and support for the fight against ebola will be needed for a considerable share of 2015.

There are several explanations why things went as bad as they did. The West African population is mobile and people often maintain close relations to their regions of origin, regardless of where they live. These relations may be a prerequisite to trade, agriculture or other professions; moreover, they are rooted in traditions that have existed for hundreds of years.

In times of crises, it is particularly important that people who form part of a traditional culture maintain their relations to their villages of origin, among others to perform rituals and ceremonies, including burials.

Therefore, the ongoing epidemic gained a previously unseen geographical spreading that included simultaneous affection of several village areas as well as densely populated areas in the capitals of Guinea, Liberia and Sierra Leone. Thus, the epidemic may be characterised as the simultaneous occurrence of a number of larger and smaller outbreaks that are under varying degree of control, rather than as a homogeneous spreading with a uniform level of control.

Additionally, the epicentre was situated in the area where the three countries meet. Close relations exist between the people that inhabit this border area, and a substantial share of the population belongs to the ethnic group, Kissi, that shares the same language. Therefore, the border is very "porous".

The coordination of the response to the outbreak was marred by the fact that three different states were affected; three countries that had no previous experience with ebola outbreaks, no tradition for joint crisis management and all three with very weak healthcare sectors where the population has only limited confidence in the state, authorities and experts. Furthermore, both Liberia and Sierra Leona have been afflicted by civil war.

Late acknowledgement of the epidemic's existence on the part of both national authorities and international organisations further added to a very unfortunate combination of circumstances. We can only hope that 2015 will see this complex epidemic controlled.

MERS coronavirus, new influenza types and enterovirus

Internationally, 2014 was also characterised by other events, such as the continual finding of infection with the Middle East Respiratory Syndrome coronavirus (MERS-CoV), EPI-NEWS 19/14. To this date, 945 cases have been detected of this often serious infection, including a minimum of 348 deaths.

The majority of cases have occurred in citizens of the Middle East (particularly from Saudi Arabia). There is increasing acknowledgement that this infection may also present as much less seriously affected clinical cases. Furthermore, there are strong indications that camels may be a source of infection for MERS-CoV. It is still relevant to be aware of this new virus as a differential diagnostic option in severe infections among patients who have stayed on the Arabian Peninsula or in any neighbouring countries, EPI-NEWS 19/14.

2014 saw reports of transmission to humans of several variants of avian influenza, including influenza A (H7N9) in China and the previously described influenza A (H5N1) in Asia and North Africa, EPI-NEWS 9/14. In 2014, a special subtype of enterovirus EV-D68 also gave rise to major outbreaks of airway infections in the US and Canada, and cases were detected in Denmark, EPI-NEWS 49/14. The continued spread of polio also caused international concern in 2014 and led to tightened requirements for vaccination when staying in certain countries, EPI-NEWS 27a and 27b/14.

The increasing realisation of new causes for airway infections probably reflects that today’s international monitoring systems are better equipped to detect new variants of airway virus or other pathogens than was previously the case.

Listeria in Denmark

In 2014, Denmark was affected by a major listeria outbreak counting a total of 41 cases, including 17 deaths. Experience has demonstrated that listeria outbreaks are difficult to track as listeria infections may be caused by a wide range of sources. The incubation period is variable (and in some cases long), and the affected cases are often patients who are weakened by other conditions and therefore not available for interviews.

Thanks to the use of whole-genome sequencing of Listeria monocytogenes isolates submitted from patients and foods, in combination with interview information, it was possible to track the infection back to cold cuts from a single company, EPI-NEWS 35/14, which very probably prevented further cases of disease and death.

2014 also saw other remarkable breakthroughs in the tracing of sources of listeria outbreaks, and it is expected that future use of whole-genome sequencing may contribute to improved tracing of listeria infections and therefore allow us to stop more outbreaks than has previously been the case.

Livestock MRSA of the CC398 type and other resistant bacteria

The listeria outbreak was covered massively by Danish media. Also the substantial spreading of methicillin-resistant staphylococci (MRSA) of the CC398 type ("livestock MRSA") was discussed extensively in the press, with active contributions from both experts and tireless laypersons. It is encouraging that both professional communities and the media focus on resistant bacteria.

Antibiotic resistance is one of the primary challenges facing Danish as well as international healthcare. Nearly all treatment modalities in hospitals directly or indirectly depend on access to effective antibiotics. MRSA of both "human types" and the zoonotic types is a problem that we need to take seriously, EPI-NEWS 24a and 24b/14.

But major challenges relating to other types of resistant bacteria exist, e.g. vancomycin-resistant enterococci and not least ESBL-producing and carbapenem-resistant gram-negative bacteria such as Escherichia coli and Klebsiella pneumoniae, EPI-NEWS 42-43/14. It is important that an increased focus on MRSA does not cause other issues relating to antibiotic resistance to be overlooked.

Vaccination reminders sent out by Statens Serum Institut

In response to an initiative from the Danish Ministry of Health, in May 2014 Statens Serum Institut started sending out childhood vaccination reminders to parents who have children that turn 2, 6.5 or 14 years old, EPI-NEWS 20/14. The reminders are only sent out if the children at the time are registered as lacking a minimum of one of the vaccinations that are recommended under the childhood vaccination programme.

The purpose of the initiative is to ensure that as many children as possible are protected against the serious diseases that may be prevented through vaccination. The reminders are generated on the basis of vaccination information recorded in the Danish Vaccination Register and therefore also available for citizens and healthcare workers through the Joint Medicine Card (Danish: Det Fælles Medicinkort) www.fmk-online.dk.

Submission of the many letters is the most extensive citizen-focused campaign that Statens Serum Institut has handled in recent years. In some cases parents have received a reminder even though their children have, in fact, received the recommended vaccinations.

This will also occur in the future. One of the reasons for this is that it can take up to 3 months from a vaccination is given until it appears in the vaccination register. Furthermore, some vaccinations are not registered for other reasons. This applies to vaccinations given abroad, and vaccinations that the physician has not reported to the National Danish Health Insurance, e.g. because a consultation rather than a vaccination was settled.

Statens Serum Institut has tried as best it can to handle the many questions that the reminder scheme has triggered. We are aware that this initiative has also triggered a quite substantial number of requests from parents to healthcare practitioners and are content that the reminder scheme has, generally, been received in a positive spirit.

The overall result will be a heightened vaccination coverage, but also an improved registration of vaccines, which will allow the Danish Vaccination Register to serve as a reliable electronic vaccination card in future.
(K. Mølbak, Department of Infectious Disease Epidemiology)

Link to previous issues of EPI-NEWS

7 January 2015