Phylogenetic and epidemiological analysis of measles outbreaks in Denmark, 2013 to 2014.

Despite the introduction of safe, effective vaccines decades ago and joint global public health efforts to eliminate measles, this vaccine-preventable disease continues to pose threats to children's health worldwide. During 2013 and 2014, measles virus was introduced into Denmark through several independent importations. This resulted in a number of secondary cases (n=7), with two clusters in 2013 and one in 2014. In total, there were 44 cases of measles. Most cases (n=41) were laboratory confirmed by detection of measles virus genome by real-time reverse transcription (RT)-PCR and IgM antibodies. The viruses from confirmed cases were genotyped by sequencing. Only one genotype circulated each year, i.e. D8 and B3, respectively. Sequencing of measles virus from different clinical specimens from the same patients revealed that sequence variants of measles viruses might co-exist and co-transmit during an outbreak. The majority of the cases were unvaccinated (n=27) or recipients of one dose of measles-mumps-rubella (MMR) vaccine (n=7). In addition, two fully vaccinated adult cases were reported in 2014. We demonstrate the transmission of measles virus in a population in which the two-dose MMR vaccination coverage rate was 80% and how even vaccinated individuals may be at risk of contracting measles once transmission has been established.

Meticillin-resistant Staphylococcus aureus CC398 is an increasing cause of disease in people with no livestock contact in Denmark, 1999 to 2011.

Livestock constitutes a potential reservoir of meticillin-resistant Staphylococcus aureus isolates belonging to a recently derived lineage within clonal complex 398 (MRSA CC398-IIa). Since its discovery in the early 2000s, this lineage has become a major cause of human disease in Europe, posing a serious public health challenge in countries with intensive livestock production. To retrace the history of human colonisation and infection with MRSA CC398-IIa in Denmark, we conducted a nationwide, retrospective study of MRSA isolates collected from 1999 to 2011. Among 7,429 MRSA isolates screened, we identified 416 MRSA CC398-IIa isolates. Of these, 148 were from people with infections, including 51 from patients reporting no livestock exposure. The first cases of MRSA CC398-IIa infection in Denmark occurred in 2004. Subsequently, the incidence of MRSA CC398-IIa infection showed a linear annual increase of 66% from 2004 to 2011 (from 0.09 to 1.1 per 100,000 person-years). There were clear temporal and spatial relationships between MRSA CC398-IIa-infected patients with and without livestock exposure. These findings suggest substantial dissemination of MRSA CC398-IIa from livestock or livestock workers into the Danish community and underscore the need for strategies to control its spread both on and off the farm.

Mumps resurgence in Denmark.

BACKGROUND: The past decade has witnessed a resurgence of parotitisvirus (mumps) in several countries where seemingly good mumps control otherwise had been achieved through vaccination. Recently detection of mumps has increased in Denmark. OBJECTIVES: To describe the age-specific changes and time trends of parotitisvirus detection in Denmark over a 10 year period. STUDY DESIGN: Retrospective cohort study based on national laboratory data for parotitisvirus typing surveillance and national epidemiology data for mumps reporting. RESULTS: The parotitisvirus detection rate has increased almost 10 times during the past 10 years from an incidence <0.1 per 100,000 in 2003 to 0.96 per 100,000 in 2013. The age distribution has shifted from children to young adults, and most cases are unvaccinated (54%) or vaccinated once (41%). The increase is due mainly to the existence of cohorts with low MMR vaccine coverage. CONCLUSION: Analysis of mumps surveillance data from Denmark documents that the incidence of mumps is increasing, and that the resurgence of parotitisvirus is primarily occurring among young Danish adults. Almost half of the infected clinical mumps cases had received the first dose of MMR.