Eurosurveillance - Volume 29, Issue 18, 02 May 2024

Tick-borne encephalitis (TBE) is a severe, vaccine-preventable viral infection of the central nervous system. Symptoms are generally milder in children and adolescents than in adults, though severe disease does occur. A better understanding of the disease burden and duration of vaccine-mediated protection is important for vaccination recommendations.

To estimate TBE vaccination coverage, disease severity and vaccine effectiveness (VE) among individuals aged 0–17 years in Switzerland.

Vaccination coverage between 2005 and 2022 was estimated using the Swiss National Vaccination Coverage Survey (SNVCS), a nationwide, repeated cross-sectional study assessing vaccine uptake. Incidence and severity of TBE between 2005 and 2022 were determined using data from the Swiss disease surveillance system and VE was calculated using a case–control analysis, matching TBE cases with SNVCS controls.

Over the study period, vaccination coverage increased substantially, from 4.8% (95% confidence interval (CI): 4.1–5.5%) to 50.1% (95% CI: 48.3–52.0%). Reported clinical symptoms in TBE cases were similar irrespective of age. Neurological involvement was less likely in incompletely (1–2 doses) and completely (≥ 3 doses) vaccinated cases compared with unvaccinated ones. For incomplete vaccination, VE was 66.2% (95% CI: 42.3–80.2), whereas VE for complete vaccination was 90.8% (95% CI: 87.7–96.4). Vaccine effectiveness remained high, 83.9% (95% CI: 69.0–91.7) up to 10 years since last vaccination.

Even children younger than 5 years can experience severe TBE. Incomplete and complete vaccination protect against neurological manifestations of the disease. Complete vaccination offers durable protection up to 10 years against TBE.

The pet industry is expanding worldwide, particularly raw meat-based diets (RMBDs). There are concerns regarding the safety of RMBDs, especially their potential to spread clinically relevant antibiotic-resistant bacteria or zoonotic pathogens.

We aimed to investigate whether dog food, including RMBD, commercially available in Portugal can be a source of Salmonella and/or other Enterobacteriaceae strains resistant to last-line antibiotics such as colistin.

Fifty-five samples from 25 brands (21 international ones) of various dog food types from 12 suppliers were screened by standard cultural methods between September 2019 and January 2020. Isolates were characterised by phenotypic and genotypic methods, including whole genome sequencing and comparative genomics.

Only RMBD batches were contaminated, with 10 of 14 containing polyclonal multidrug-resistant (MDR) Escherichia coli and one MDR Salmonella. One turkey-based sample contained MDR Salmonella serotype 1,4,[5],12:i:- ST34/cgST142761 with similarity to human clinical isolates occurring worldwide. This Salmonella exhibited typical antibiotic resistance (blaTEM + strA-strB + sul2 + tet(B)) and metal tolerance profiles (pco + sil + ars) associated with the European epidemic clone. Two samples (turkey/veal) carried globally dispersed MDR E. coli (ST3997-complexST10/cgST95899 and ST297/cgST138377) with colistin resistance (minimum inhibitory concentration: 4 mg/L) and mcr-1 gene on IncX4 plasmids, which were identical to other IncX4 circulating worldwide.

Some RMBDs from European brands available in Portugal can be a vehicle for clinically relevant MDR Salmonella and pathogenic E. coli clones carrying genes encoding resistance to the last-line antibiotic colistin. Proactive actions within the One Health context, spanning regulatory, pet-food industry and consumer levels, are needed to mitigate these public health risks.