Epidemiological News: Week 49, 2025
Veterinary Medicines Regulatory Developments
The European Medicines Agency’s Committee for Veterinary Medicinal Products (CVMP) convened 2–4 December 2025 and adopted several notable opinions. Positive marketing authorisation opinions were issued for Varenzin (molidustat) for managing non-regenerative anaemia in cats with chronic kidney disease, Firocoxib CP-Pharma for pain and inflammation in dogs, and—under exceptional circumstances—an epizootic haemorrhagic disease vaccine (serotype 8) for cattle from Laboratorios Syva. The Committee also adopted a positive opinion for Dexdomitor’s new indication as a constant rate infusion during inhalation anaesthesia in dogs and cats.
Of particular relevance to antimicrobial stewardship, the CVMP concluded its review of Phenoxypen WSP (phenoxymethylpenicillin) for chickens following a European Commission request for clarification, determining by majority that the benefit-risk balance is positive with specified amendments. The Committee also adopted the second European Sales and Use of Antimicrobials for veterinary medicine (ESUAvet) report for 2024, scheduled for publication on 9 December 2025. Additionally, a modified maximum residue limit opinion for lidocaine in porcine species was adopted, permitting scrotal/testicular injection in piglets up to 7 days of age—relevant to animal welfare improvements in castration procedures. The Committee adopted work plans for 2026 across all working parties, including the Antimicrobials Working Party.
Infectious Diseases - Global perspective
Avian Influenza A(H5N2) – Genetic Analysis Update
Additional genetic analysis has been completed for the second human case of avian influenza A(H5N2) in Mexico, confirmed on 24 November 2025. The sequenced strain (A/Mexico City/INER INF1427/2025) belongs to clade 2.3.4.4b and, unlike the first case from 2024 which involved low pathogenic avian influenza, demonstrates a highly pathogenic avian influenza signature in the hemagglutinin segment.
Notably, the strain appears to result from a reassortment event between an enzootic low pathogenic A(H5N2) virus ancestor from 2024 and A(H5N1) clade 2.3.4.4b genotype B3.2 viruses, with a new genotype designation (B3.14) proposed. While no mutations known to increase zoonotic potential were identified in the consensus sequence, deeper analysis of sequencing reads revealed minor variants of K526R and E627K in PB2—markers associated with enhanced replication in mammalian cells. No human-to-human transmission has been detected. The risk of zoonotic influenza transmission to EU/EEA populations remains low.
Vector-Borne, Contact and Sexual Transmission
Marburg Virus Disease – Ethiopia (Update)
The Marburg virus disease outbreak in Ethiopia continues to evolve, with one additional confirmed case reported since 28 November 2025. As of 4 December, cumulative figures stand at 16 cases (13 laboratory-confirmed, 3 probable) with 11 deaths (8 confirmed, 3 probable), yielding a case fatality rate of 61.5% among confirmed cases—slightly lower than the 66.7% reported in week 48, likely reflecting improved supportive care and earlier case detection.
Geographic expansion continues to be a concern. Cases have now been confirmed in two regions: Jinka city in Omo Zone, South Ethiopia Regional State (the outbreak epicenter), and Hawassa City in Sidama Region. The Hawassa case was confirmed in an individual who had returned from Jinka City, demonstrating inter-regional spread through population movement. Contact tracing has identified 349 individuals, with 119 (34.1%) having completed their 21-day monitoring period. Four cases have recovered and one patient remains under treatment.
The virus strain shows genetic similarities to previously identified East African Marburg variants. Response efforts continue under Ministry of Health leadership with WHO and international partner support, focusing on community-level monitoring, contact tracing, and house-to-house case finding. ECDC maintains its assessment of low overall risk for EU/EEA citizens visiting or living in Ethiopia, with very low likelihood of importation and secondary transmission.
Ebola Virus Disease – Democratic Republic of the Congo (Outbreak Concluded)
On 1 December 2025, WHO officially declared the end of the Ebola virus disease outbreak in Kasai Province, DRC, following 42 days without new cases since the last patient’s discharge on 19 October 2025. This was the sixteenth Ebola outbreak recorded in DRC since 1976 and the eighth since 2018.
The final outbreak tally includes 64 cases (53 confirmed, 11 probable) and 45 deaths (34 confirmed, 11 probable), with an overall case fatality rate of 70.3%. All cases were confined to six health areas within Bulape health zone. A total of 19 patients recovered (29.7%), and all 1,735 contacts who were followed completed their monitoring. Vaccination efforts reached approximately 48,000 individuals, and 31 patients received monoclonal antibody therapy (mAb114).
Genomic sequencing confirmed this outbreak represented a new zoonotic spillover event unrelated to previous outbreaks. The initial transmission was characterized by nosocomial spread and a superspreading event linked to the presumptive index case’s funeral. The DRC now enters a 90-day period of enhanced disease surveillance.
Fecal-Oral Transmission
Shigellosis – Multi-Country Outbreak in Cape Verde Travelers (Resurgence)
A recurrent multi-country outbreak of shigellosis among travelers returning from Cape Verde has resurged dramatically, with at least 193 cases reported across five EU/EEA countries and the United Kingdom during 2025. This outbreak, which first emerged in September 2022, continues to demonstrate persistent transmission of the same Shigella sonnei strain, suggesting a common source or ongoing transmission route at specific tourist locations.
Shigella sonnei causes bacillary dysentery through fecal-oral transmission, with an incubation period of 1–3 days. Clinical presentation includes bloody diarrhea, fever, and abdominal cramps. Transmission occurs through contaminated food or water or person-to-person spread. While typically self-limiting in healthy adults, severe disease can occur, particularly with antimicrobial-resistant strains. The outbreak strain demonstrates limited genetic antimicrobial resistance markers, though most isolates harbor dfrA1 predicting trimethoprim resistance.
Country-specific data reveal the outbreak’s scope: the UK has reported 137 confirmed cases since 1 October 2025, with 94% of those reporting travel indicating Cape Verde as their destination. Among cases with hotel information (n=75), 71 stayed at hotels in the Santa Maria and Boa Vista areas. Sweden reported 26 cases in 2025 (23 since late October), with co-infections of salmonellosis (4) and campylobacteriosis (1) also noted among returning travelers. France reported 21 cases (up from 5–6 annually in 2023–2024), the Netherlands reported 8 cases in September-October, and Ireland reported 1 case.
Available case interviews consistently implicate a specific hotel/resort chain in the Santa Maria region of Sal island and on Boa Vista island—the same locations identified during the 2022 outbreak. The persistence of the same genomic strain over multiple years strongly suggests ongoing environmental contamination or systematic food safety failures at implicated accommodations. ECDC assesses the risk for EU/EEA citizens traveling to Cape Verde of contracting shigellosis as moderate.
European Union/European Economic Area
Respiratory and Droplet Transmission
Seasonal Respiratory Virus Activity – Accelerating Influenza Season
The 2025–26 influenza season continues to accelerate across the EU/EEA, with approximately half of reporting countries now showing respiratory illness consultation rates above baseline. This represents significant ongoing respiratory virus circulation as winter progresses.
Influenza virus detection continues to increase, with most countries reporting widespread activity at low-to-medium intensity—a notable escalation from the previous week’s assessment. Influenza A remains dominant (99% of typed specimens), with A(H3N2) subclade 2a.3a.1(K) accounting for 88% of genetically characterized A(H3) specimens and driving the current increasing trend. In week 48, primary care sentinel surveillance detected 591 influenza specimens with 21% pooled positivity (median 13%; IQR 8.1–24%), while hospital SARI surveillance identified 305 influenza specimens with 19% pooled positivity. The week-on-week increase from 16% to 21% pooled positivity in primary care demonstrates the season’s rapid progression.
Geographic spread has expanded considerably: 11 countries now report widespread activity (up from 5 the previous week), 3 report regional spread, 1 local, 5 sporadic, and only 1 reports no activity. Five countries report baseline intensity, 12 report low intensity, and 5 report medium intensity. Children aged 5–14 years continue to show the highest circulation rates, while hospitalization increases are primarily affecting adults aged 65 years and above.
Respiratory syncytial virus (RSV) circulation is slowly increasing from low levels but remains below what was observed at this time in the past four seasons. Hospital data show rising RSV-related admissions in a few countries, primarily among children under five years. SARS-CoV-2 continues to circulate but is decreasing across all age groups, with limited impact on hospitalizations.
ECDC’s Threat Assessment Brief published 20 November 2025, assessing the risk of influenza for the EU/EEA in the context of increasing A(H3N2) subclade K circulation, remains relevant as the season intensifies.
Vector-Borne Transmission
Chikungunya Virus Disease – 2025 Season Conclusion
ECDC has concluded its weekly reporting for the 2025 chikungunya season as unfavorable seasonal weather conditions make further locally acquired cases unlikely. No new cases were reported in week 49, and eight previously reported cases were eliminated following epidemiological review.
Final 2025 season figures stand at 1,172 locally acquired cases across France (788) and Italy (384), distributed among 84 clusters. France’s cases occurred across 78 clusters (largest in Antibes), while Italy’s cases were distributed across 6 clusters (largest in the Emilia-Romagna region towns of Carpi, San Prospero, Soliera, and others). Three clusters in France and two in Italy remain technically active based on reporting windows, though transmission has likely ceased. The 2025 season represents significant local transmission, underscoring the importance of vector control and surveillance during favorable transmission periods.
West Nile Virus – Season Update
Since the beginning of 2025 and as of 3 December, 14 European countries have reported human West Nile virus cases, with 157 affected areas identified. Bulgaria is among the reporting countries, along with Albania, Croatia, France, Germany, Greece, Hungary, Italy, Kosovo, North Macedonia, Romania, Serbia, Spain, and Türkiye. The vector transmission season has effectively concluded.
Fecal-Oral Transmission
Hepatitis A – Multi-Country Outbreak (Continued Monitoring)
The multi-country hepatitis A outbreak affecting Austria, Czechia, Hungary, and Slovakia continues, though no new updates were provided in the week 49 ECDC report. The outbreak, exceeding 6,000 cumulative cases and 39 deaths in 2025, remains driven by person-to-person transmission among populations with limited access to sanitation. ECDC’s recommendations from the June 2025 Rapid Risk Assessment remain valid, emphasizing enhanced surveillance, vaccination for high-risk populations, and community engagement.
HIV/AIDS Surveillance – 2024 Annual Data
ECDC released 2024 HIV/AIDS surveillance data, revealing continued challenges in the EU/EEA despite declining trends. In 2024, 24,164 HIV diagnoses were reported across 30 EU/EEA countries (rate: 5.3 per 100,000), representing a 14.5% decrease from the 2015 rate of 6.2 per 100,000. However, this decline should be interpreted cautiously as standard reporting-delay adjustments were not applied.
The epidemic remains predominantly sexually transmitted (96%), with sex between men accounting for 48.3% (53.2% of known transmission routes) and heterosexual contact for 33.6% (45.7% of known routes). Migrants comprised 47.2% of all diagnoses; when excluding unknown origins, this proportion rises to 55.7%—a 45.4% increase from 2015’s 33.1%. Late diagnosis (CD4 <350 cells/mm³) remains problematically high at 48.0%, indicating persistent gaps in testing access and awareness.
AIDS diagnoses totaled 2,215 across 25 countries (rate: 0.7 per 100,000), with Pneumocystis jirovecii pneumonia (22.4%) and tuberculosis (11.7%) representing the most frequent AIDS-defining illnesses. These data underscore the continued need for expanded HIV testing, rapid linkage to care, pre-exposure prophylaxis programs, and harm reduction services.
Infectious Diseases: Bulgaria
Respiratory and Droplet Transmission
COVID-19
Bulgaria recorded 71 COVID-19 cases during week 49, essentially unchanged from the previous week (69 cases, +2.9%). Year-to-date cases (3,030) represent an 80.0% reduction compared to 2024 (15,135), consistent with endemic circulation patterns and reduced surveillance intensity. All reported cases were laboratory confirmed.
Pertussis (Whooping Cough)
No pertussis cases were registered during week 49, representing a decrease of 3 cases from the previous week. Year-to-date cases (88) remain dramatically lower than 2024 (2,718), confirming the post-epidemic normalization following the 2024 surge that affected Bulgaria and much of Europe. The 96.8% year-to-date decrease demonstrates the cyclical nature of pertussis epidemiology following the disruption of childhood vaccination programs during the COVID-19 pandemic.
Legionnaires’ Disease
One case of Legionnaires’ disease was confirmed during week 49, a decrease of 1 from the previous week. Year-to-date cases (16) exceed 2024 totals (11) by 45.5%, warranting continued environmental surveillance of water systems, particularly in healthcare facilities and hotels during the winter months when building water systems may be more susceptible to Legionella colonization.
Pneumococcal Bacterial Meningitis and Meningoencephalitis
One case of pneumococcal bacterial meningitis/meningoencephalitis was confirmed during week 49, following zero cases the previous week. Year-to-date cases (22) are unchanged from 2024 (22). Invasive pneumococcal disease remains an important cause of severe bacterial infection, particularly in young children and elderly adults.
Fecal-Oral Transmission
Sixty-three acute viral hepatitis cases were reported during week 49, representing a significant 43.2% increase from the previous week (44 cases). Of these, 57 were laboratory confirmed, 2 probable, and 4 possible. This week-to-week increase reverses the 48.8% decrease observed between weeks 47 and 48, demonstrating continued volatility in hepatitis transmission.
Year-to-date cases (1,510) represent a 129.8% increase compared to 2024 (657), making viral hepatitis the most dramatically elevated disease category in Bulgarian surveillance this year. This substantial increase likely reflects the broader Central European hepatitis A outbreak affecting neighboring countries, though Bulgaria’s specific contribution by hepatitis type requires characterization. Given Bulgaria’s geographic proximity to heavily affected Hungary and Romania, enhanced surveillance for HAV among high-risk populations remains warranted.
A total of 149 cases of gastroenteritis and enterocolitis were recorded during week 49, a decrease of 20 cases (11.8%) from the previous week. Case classification included 62 possible, 84 probable, and 3 confirmed. Year-to-date cases (8,997) represent a 6.1% decrease compared to 2024 (9,577), consistent with secular trends.
Eleven salmonellosis cases were confirmed during week 49, representing a substantial 52.2% decrease from the previous week (23 cases). All cases were laboratory confirmed. Year-to-date cases (672) are 25.1% lower than 2024 (897). The marked week-to-week decrease suggests the previous week’s uptick may have represented a transient cluster rather than sustained transmission.
Six campylobacteriosis cases were confirmed during week 49, a dramatic 68.4% decrease from the previous week (19 cases). Despite this weekly decrease, year-to-date cases (462) continue to exceed 2024 totals (322) by 43.5%. The persistent year-to-date increase throughout 2025 warrants continued investigation into potential sources and risk factors, even as weekly case counts fluctuate.
Six escherichiosis cases were confirmed during week 49, a 200% increase from the previous week (2 cases). All cases were laboratory confirmed. Year-to-date cases (301) remain 14.2% below 2024 (351). The week-to-week variation likely reflects sporadic rather than outbreak-related transmission.
Ten rotavirus gastroenteritis cases were confirmed during week 49, unchanged from the previous week. Year-to-date cases (701) are 15.7% lower than 2024 (832), likely reflecting continued benefits of childhood rotavirus vaccination programs.
One confirmed shigellosis case was reported during week 49, unchanged from the previous week. Year-to-date cases (55) are 28.6% lower than 2024 (77). Given the multi-country S. sonnei outbreak affecting Cape Verde travelers, clinicians should maintain awareness of travel history in patients presenting with bloody diarrhea.
Vector-Borne Transmission
Lyme Borreliosis
Five Lyme borreliosis cases were confirmed during week 49, an increase of 2 cases from the previous week. Year-to-date cases (381) are virtually unchanged from 2024 (383). The detection of cases in December is unusual given reduced tick activity during winter months and may represent delayed diagnosis of infections acquired during the transmission season.
Contact and Sexual Transmission
Sexually Transmitted Infections
Sexually transmitted infections in Bulgaria continue to demonstrate concerning upward trends across multiple pathogens.
HIV recorded 7 cases during week 49, a notable 133% increase from the previous week (3 cases). Year-to-date cases (284) represent a 5.6% increase compared to 2024 (269). The week-to-week fluctuation likely reflects reporting variation rather than acute transmission changes, though the overall upward trend merits attention.
Syphilis recorded 6 cases during week 49, a decrease of 4 from the previous week (10 cases). Year-to-date cases (348) represent a 10.5% increase compared to 2024 (315).
Congenital syphilis recorded 1 additional case during week 49, bringing year-to-date totals to 35 cases compared to 16 in 2024—a 118.8% increase. This represents one of the most significant public health signals in Bulgarian surveillance, indicating systematic failures in prenatal syphilis screening and treatment programs. Each congenital syphilis case represents a preventable pediatric outcome requiring urgent programmatic attention.
Urogenital chlamydia infection recorded 7 cases during week 49, an increase of 2 from the previous week (5 cases). Year-to-date cases (182) demonstrate a 75.0% increase compared to 2024 (104), the most pronounced increase among bacterial STIs.
Gonorrhea recorded 2 cases during week 49, a decrease of 3 from the previous week (5 cases). Year-to-date cases (116) represent a 28.9% increase compared to 2024 (90).
The consistent upward trends across all STI categories suggest systemic factors potentially including reduced prevention services, changing sexual behaviors, improved case detection, or some combination thereof.
Childhood and Vaccine-Preventable Diseases
Varicella (Chickenpox)
Varicella recorded 494 cases during week 49, a modest 6.1% decrease from the previous week (526 cases). Case classification included 55 possible, 393 probable, and 46 confirmed. Year-to-date cases (20,000) are 20.5% lower than 2024 (25,156). Current weekly counts remain consistent with expected seasonal winter transmission patterns in the absence of routine childhood varicella vaccination in Bulgaria.
Scarlet Fever
Seventy-four scarlet fever cases were reported during week 49, representing a 25.3% decrease from the previous week (99 cases). Case classification included 18 possible, 36 probable, and 20 confirmed. Year-to-date cases (3,323) remain 59.7% below 2024 totals (8,237), reflecting continued resolution of the 2024 Group A Streptococcus surge that paralleled the pertussis epidemic.