Non-Communicable Disease and Healthcare System Developments
EMA Pharmacovigilance Risk Assessment Committee: 8–11 June 2026
The PRAC concluded a multi-year safety review of valproate with a finding of persistent scientific uncertainty rather than resolution. The signal in question—a potential risk of neurodevelopmental disorders (NDDs) in children born to men treated with valproate during the three months preceding conception—was first raised in January 2024 on the basis of a post-authorisation safety study using Danish, Norwegian, and Swedish registry data, which found an increased risk relative to men treated with lamotrigine or levetiracetam. A subsequent Danish nationwide registry study, published in 2025, did not replicate this association, prompting PRAC to reopen the signal and review all available evidence in the round just concluded. The committee’s overall judgment is that the body of evidence remains inconsistent: while one study suggested a possible link, the majority of retrospective observational studies did not find an increased risk, and methodological heterogeneity across studies—particularly in patient selection and confounding adjustment for paternal underlying disease—precludes a clear causal determination. PRAC has therefore opted for continuity rather than escalation, maintaining the 2024 precautionary measures for male patients while updating product information and the existing healthcare professional and patient guides to reflect the latest evidence. A larger, purpose-designed study addressing the limitations of the original signal is already underway and is expected to report in 2028, meaning the uncertainty here is likely to persist for some time. Valproate remains widely used for epilepsy, bipolar disorder, and—in some member states—migraine prophylaxis, so the practical implication for prescribers is that current counselling practices for men of reproductive age should continue unchanged pending more definitive data.
Two further safety actions from this PRAC cycle carry more immediate clinical weight. First, the chikungunya vaccine Ixchiq—a live-attenuated vaccine authorised for individuals 12 years and older—has been restricted to people at high risk of chikungunya infection, following review of serious adverse events including aseptic meningitis, encephalopathy, and encephalitis, some of which resulted in hospitalisation or death. The adverse events disproportionately affect adults 65 years and older and those with multiple chronic comorbidities, though serious reactions have occurred in young, otherwise healthy adults as well. The vaccine remains contraindicated in immunocompromised individuals and should not be co-administered with other vaccines. This restriction is clinically relevant given the active and expanding chikungunya transmission documented in French Guiana this reporting period (discussed below), where vaccination decisions are now explicitly conditioned on individual risk rather than blanket availability. Second, PRAC has reinforced liver function monitoring requirements and introduced explicit stopping rules for avacopan (Tavneos), used in severe ANCA-associated vasculitides (granulomatosis with polyangiitis and microscopic polyangiitis), following further characterisation of drug-induced liver injury and vanishing bile duct syndrome risk, including fatal cases. Prescribers must now obtain baseline hepatic transaminases and bilirubin before treatment initiation, monitor at least fortnightly for the first three months and monthly for the subsequent three months, and permanently discontinue treatment if alkaline phosphatase exceeds twice the upper limit of normal with a hepatic source, or if clinical signs of vanishing bile duct syndrome (jaundice, pruritus) emerge. EMA is separately reviewing avacopan for data integrity concerns regarding its pivotal trial, a development that adds regulatory complexity independent of the safety findings themselves.
EMA Management Board: June 2026 Meeting
The Management Board’s June meeting was notable principally for its formalisation of EMA’s role in the ongoing Bundibugyo virus Ebola response. This is the first public health emergency in which EMA’s Emergency Task Force has engaged directly with the newly operational African Medicines Agency (AMA) alongside national African regulators on clinical trial design and candidate medical countermeasures—a structurally significant development given that, as detailed below, no licensed vaccine or treatment currently exists for Bundibugyo virus disease specifically (in contrast to Zaire ebolavirus, for which both exist). The Board’s broader 2025 activity review noted 104 positive recommendations for new human medicines, including 38 with a novel active substance, alongside continuing preparatory work for the incoming EU pharmaceutical legislation and the Biotech Act’s anticipated effects on the Clinical Trials Information System. Of more immediate operational relevance to public health data infrastructure, EMA opened a beta public API for its product management service on 12 June 2026, intended to broaden machine-readable access to authorised medicinal product data beyond the existing web interface.
Recent Research Highlights
Three randomised trials published this period bear on acute care practice. The SNAP platform trial’s bacteraemia domain (NEJM) found cefazolin noninferior to antistaphylococcal penicillins (flucloxacillin or cloxacillin) for methicillin-susceptible Staphylococcus aureus bacteraemia, with 90-day mortality of 15.0% versus 17.0% respectively (adjusted odds ratio 0.81; 95% credible interval 0.59–1.12; probability of noninferiority 99.2%), and a materially lower incidence of acute kidney injury with cefazolin (13.9% versus 19.6%; adjusted odds ratio 0.67). Given the substantial morbidity associated with antistaphylococcal penicillin-induced nephrotoxicity, this finding—drawn from an adequately powered Bayesian adaptive platform spanning 1,287 evaluable patients—supports a shift toward cefazolin as a first-line option in penicillin-resistant, methicillin-susceptible S. aureus bacteraemia.
In prehospital trauma care, the SWiFT trial (NEJM) found that prehospital whole-blood transfusion was not superior to standard component therapy (red cells and plasma) for the composite outcome of death or massive transfusion within 24 hours among 616 evaluable patients with major traumatic haemorrhage attended by UK air ambulance services (48.7% versus 47.7%; relative risk 1.02; 95% CI 0.80–1.31). This null result is clinically informative given the considerable recent momentum toward prehospital whole-blood protocols in trauma systems internationally; the trial does not support abandoning standard component therapy where whole blood is logistically constrained.
In paediatrics, the PROPOSITIS trial (JAMA) found that prone positioning in infants 6 months or younger with moderate-to-severe bronchiolitis on high-flow nasal cannula did not significantly reduce escalation to non-invasive or invasive ventilation compared with supine positioning (15.0% versus 20.8%; adjusted odds ratio 0.66; 95% CI 0.40–1.07), though the wide confidence interval leaves the question clinically unresolved rather than definitively answered. Separately, the CHAMP-UK trial (BMJ) found that low-concentration (0.01%) atropine eye drops significantly slowed myopia progression in children aged 6–12 over two years compared with placebo (mean difference in spherical equivalent refractive error 0.33 D, 95% CI 0.17–0.49; axial length difference 0.14 mm, 95% CI 0.07–0.21), with no excess of adverse events beyond a modest, expected increase in pupil diameter—evidence that should reinforce confidence in an intervention already seeing increasing clinical uptake for paediatric myopia control.
Infectious Diseases: Global Perspective
Respiratory and Droplet Transmission
Ebola Disease Outbreak (Bundibugyo Virus) — Democratic Republic of the Congo and Uganda
The Bundibugyo virus Ebola disease outbreak, declared a Public Health Emergency of International Concern by WHO on 17 May and a Public Health Emergency of Continental Security by Africa CDC the following day, continued its rapid expansion across both reporting weeks. In the Democratic Republic of the Congo, confirmed cases rose from 381 (64 deaths) as of 3 June to 676 (136 deaths) as of 10 June—an increase of 295 cases and 72 deaths over the fortnight, with the case fatality ratio rising correspondingly from 16.8% to 20.1%. Affected health zones expanded from 25 to 29 of the region’s 104, with new zones reported in both Ituri (the epicentre, now accounting for 629 of 676 cases) and North Kivu. Sixteen of the cases confirmed as of 8 June involved health and care workers, underscoring continued nosocomial risk. In Uganda, the caseload grew more modestly, from 16 to 19 confirmed cases (one to two deaths), with the most recent case reported on 5 June and no further cases since; five individuals have recovered. Of note, a case with travel history to the United Arab Emirates was investigated by WHO in coordination with UAE authorities, who confirmed as of 8 June that no Ebola cases had been detected domestically—an important reassurance given the case’s international travel link, though it also illustrates the outbreak’s potential for wider geographic reach via air travel.
Bundibugyo virus, a species of Orthoebolavirus distinct from the more frequently encountered Zaire ebolavirus, was first identified in Uganda in 2007 and has caused only one prior outbreak since (DRC, 2012), giving public health authorities comparatively limited experience with its clinical and epidemiological behaviour. Critically, no licensed vaccine or specific antiviral treatment exists for Bundibugyo virus disease, in contrast to the ring-vaccination and monoclonal antibody options available for Zaire ebolavirus outbreaks—a gap that materially constrains outbreak response options and explains EMA’s newly formalised engagement with the African Medicines Agency on candidate countermeasure development, reported in the Non-Communicable Disease section above. An American healthcare worker who had been evacuated to Berlin for treatment was discharged in good health on 6 June, providing a reassuring case example of successful supportive management outside the outbreak region. Commercial flights to and from Bunia airport, the provincial capital of Ituri, were suspended again as of 6 June as part of health security arrangements, having only briefly reopened on 2 June following a 23 May closure—reflecting the volatility of local containment measures. ECDC’s assessment, reiterated across both weeks, holds that the likelihood of infection for EU/EEA residents travelling to or living in affected areas is low, and very low for the general EU/EEA population, given the very low likelihood of importation and onward transmission; however, ECDC explicitly notes that the true scale of the outbreak is probably larger than reported, given persistent gaps in contact tracing follow-up (currently 71.8% of identified contacts) and the complex security and humanitarian context in eastern DRC that complicates case ascertainment.
Nipah Virus Disease — India and Bangladesh
A new case of Nipah virus (NiV) disease was reported on 10 June 2026 in Kozhikode district, Kerala, India: an adult in their forties presenting with encephalitis, preliminarily positive for NiV with confirmatory testing pending from the National Institute of Virology. The patient is hospitalised on ventilator support in stable condition; exposure is suspected to have occurred while cleaning a warehouse, though the source remains unconfirmed. Of 77 identified contacts—58 healthcare workers, 14 family members, and five co-workers or friends—two have been classified as highest risk and 13 as high risk, all placed under immediate quarantine; no secondary cases have emerged to date. This event follows two earlier 2026 cases: a fatal case in Rajshahi Division, Bangladesh (confirmed 6 February, with raw date palm sap consumption as the likely exposure) and two cases in West Bengal, India (confirmed 26 January), continuing the pattern of recurrent NiV spillover in the Bangladesh–eastern India henipavirus belt that has characterised this pathogen since its initial 1999 identification in Malaysia and Singapore.
Nipah virus, a Henipavirus with case fatality rates historically ranging widely depending on outbreak and clinical management (commonly cited as 40–75% in South Asian outbreaks), is transmitted from bats (the natural reservoir) to humans via direct contact, contaminated food—classically raw date palm sap—or, less commonly, human-to-human contact through bodily fluids or aerosols. The incubation period of 4–14 days and clinical progression from nonspecific febrile illness to encephalitis make early case recognition difficult outside endemic-aware clinical settings, a difficulty reflected in this case’s history of multiple healthcare visits, including for MRI and echocardiography, before NiV was suspected. ECDC assesses the likelihood of exposure for EU/EEA travellers to India or Bangladesh as very low given the low absolute number of cases in the affected districts, and notes that the absence of the natural bat reservoir in Europe makes further spread following any hypothetical importation very low.
Vector-Borne Transmission
Seasonal West Nile Virus Surveillance
ECDC’s weekly seasonal WNV surveillance, now in its third report of 2026, continues to show minimal activity: as of 10 June, only North Macedonia has reported a human case (Vardarski region), a figure unchanged across both reporting weeks. Seasonal weather conditions are assessed as increasingly favourable for mosquito-borne transmission, and ECDC anticipates rising case counts in subsequent weeks as the season progresses—a baseline against which Bulgaria’s own zero-case WNV surveillance status (noted in the national section below) should be interpreted as still consistent with early-season expectations rather than a meaningful divergence.
Chikungunya Virus Disease — French Guiana
Chikungunya transmission in French Guiana continued to intensify, with 621 confirmed autochthonous cases reported since 1 January 2026 as of 31 May—40, 61, and 33 cases in successive recent weeks—the majority (70%) concentrated in the Littoral ouest sector bordering Suriname, which entered the highest-severity “epidemic” phase on 23 April. The Savanes and Ile de Cayenne sectors have since progressed to the “outbreak clusters” phase. The circulating strain belongs to the ECSA genotype without the E1-A226V mutation associated with enhanced Aedes albopictus transmissibility, and shows close genetic relationship to recent Cuban and Brazilian sequences, consistent with regional viral circulation rather than a locally evolved variant. The comparison to French Guiana’s 2014–2015 outbreak—which produced over 16,000 suspected cases and an eventual seroprevalence of 20%—suggests the current event has substantial potential for further growth given the ongoing rainy season (January–July) and the documented presence of competent Aedes vectors. This development is directly relevant to the PRAC chikungunya vaccine restriction discussed above: with Ixchiq now limited to high-risk individuals following safety signal review, the calculus for any traveller or resident vaccination strategy in response to this outbreak is now more individualised than it would have been under the vaccine’s original broader indication. ECDC assesses traveller infection likelihood as low and onward EU/EEA transmission likelihood as low but rising, given improving conditions for Aedes activity in mainland Europe as summer approaches.
Contact and Sexual Transmission
Dermatophilus congolensis Infection Among Men Who Have Sex With Men — EU/EEA
A genuinely novel epidemiological signal has emerged in the form of an apparent shift in transmission ecology for Dermatophilus congolensis, a bacterium historically associated with animal infection (dermatophilosis in livestock) and only rarely documented in humans. As of 1 June, 50 cases have been reported via EpiPulse or peer-reviewed publication across three countries: 40 in France (predominantly Lyon, with whole-genome sequencing of eight isolates showing 1–5 single-nucleotide polymorphism differences, indicating a likely common transmission source), 17 in Germany (Berlin and adjacent Brandenburg), and a smaller, more geographically dispersed cluster of cases under investigation in Spain, including one with travel history to Asia. Across these clusters, cases are reported almost exclusively among men who have sex with men, the majority with a history of attending sex-on-premises saunas, with symptom onset concentrated between December 2025 and May 2026. Clinically, the infection has presented as mild, self-limited skin lesions—most commonly affecting the genitals, thighs, groin, and beard area—resolving fully after a course of amoxicillin, with no complications reported.
The epidemiological significance here lies less in disease severity than in the apparent novelty of the transmission route: ECDC’s assessment explicitly characterises this as a probable shift toward human-to-human spread, likely via skin-to-skin contact facilitated by humid, hot sauna environments, for a pathogen with no previously documented sexual or close-contact transmission pattern in humans. This is the first reported event of its kind, introducing genuine uncertainty about its future trajectory; ECDC rates the preliminary risk as very low for the general EU/EEA population but moderate for men who have sex with men attending sex-on-premises saunas in the affected areas, and is preparing a Rapid Risk Assessment (expected 23 June) alongside enhanced surveillance and clinician awareness-raising ahead of the summer Pride season, when relevant venue attendance and travel are both expected to increase.
Multi-Country Cluster of Salmonella Stanley ST2045
The multi-country Salmonella Stanley ST2045 cluster, under investigation since Denmark’s initial March 2026 EpiPulse notification, remains active: as of 5 June, 83 confirmed cases have been reported across nine countries (Austria, Czechia, Denmark, Estonia, France, Germany, Lithuania, the Netherlands, and the UK), with symptom onset spanning December 2025 to mid-May 2026 and at least 20 hospitalisations. A further 24 cases identified in 2026 remain unsequenced and may be linked, and new cases continue to emerge, indicating ongoing rather than resolved exposure. Children and young adults remain disproportionately represented. Epidemiological and microbiological investigation continues to point toward chicken-flavoured instant noodles and/or processed chicken products as the suspected vehicle, with some cases reporting consumption of the noodle seasoning without cooking—a use pattern at odds with manufacturer instructions and a specific, actionable consumer-facing message that ECDC has reiterated. A joint ECDC–EFSA rapid outbreak assessment is expected by 1 July.
Infectious Diseases: European Union / European Economic Area
One Health: Animal Disease Events in the European Region
WOAH follow-up reporting across the fortnight documents an unusually active period for avian influenza A(H5N1) in wild birds and poultry across the EU/EEA, with Germany alone generating more than a dozen separate follow-up reports spanning recurrences dating back to autumn 2025, alongside active events in the United Kingdom, Spain, Estonia, Slovenia, Finland, Austria, France, Italy, and Romania. While none of these reports indicate human cases, the sheer geographic breadth of concurrent wild bird and poultry involvement across the region represents a sustained spillover risk substrate that warrants continued One Health vigilance, particularly given H5N1’s demonstrated capacity for occasional severe human infection elsewhere globally. African swine fever continues its entrenched circulation in Poland, Hungary, Germany, Greece, and Croatia, with several Polish reports documenting first occurrences in previously unaffected zones as recently as May 2026, reinforcing the persistent challenge this disease poses to EU swine trade and biosecurity. Of more direct relevance to Bulgaria, Romania reported a first-occurrence case of peste des petits ruminants virus on 3 June 2026—a disease not previously established in the country—alongside new bluetongue virus serotype 3 detections and an anthrax recurrence, all in a neighbouring EU member state with which Bulgaria shares both a land border and, for several of these pathogens, comparable agroecological conditions. Bulgaria’s own WAHIS entry this period was a recurrence of sheep pox and goat pox (dating to mid-2025), a disease with no zoonotic potential but with continued relevance for regional small ruminant trade.
Vector-Borne and Zoonotic Disease
Hantavirus Cruise Ship Outbreak — Resolution
The Andes hantavirus (ANDV) outbreak aboard the Dutch-flagged cruise ship MV Hondius, first reported in early May, has effectively concluded: as of 11 June, the total stands at 13 cases (12 confirmed, one newly reclassified from probable to confirmed following laboratory testing of a case in Tristan da Cunha), with no new deaths reported since the prior update. Genomic sequencing confirmed high similarity between isolates, consistent with an initial zoonotic spillover—most likely acquired by the index case during pre-boarding travel in Argentina, where ANDV is endemic—followed by limited human-to-human transmission among close contacts aboard ship, a transmission mode well documented for this particular hantavirus species though rare among the broader Hantaviridae family. With passengers and crew now fully disembarked and dispersed (122 via Tenerife on 10–11 May, the remainder via Rotterdam on 18 May) and the vessel disinfected, ECDC maintains its assessment that the risk to the general EU/EEA population from this event is very low, reflecting both the absence of the ANDV rodent reservoir (Oligoryzomys spp.) in Europe and the documented requirement for close, prolonged contact for any further human-to-human spread. This event is now formally resolved from an active-monitoring standpoint, though it warrants retrospective note in the report series given its earlier prominence.
Measles — Multi-Country Monitoring, with Bulgaria as a Leading National Cluster
ECDC’s June measles monitoring report, covering April 2026 data with epidemic intelligence supplementation to 11 June, confirms that case numbers across the EU/EEA increased month-on-month, with 451 cases reported by 17 of 29 reporting countries in April alone. Critically for this report series, Bulgaria is identified as the second-highest national case contributor in the most recent epidemic intelligence update, with 364 cases reported from 1 January to 8 June 2026—a count dramatically higher than the two cases reported in the equivalent period of 2025, and trailing only England (736 cases, including two deaths) among reporting jurisdictions. ECDC’s country-level summary corroborates the district-level pattern already evident in Bulgarian national surveillance (detailed below): cases concentrated in Vratsa (198), Pleven (101), and Lovech (41), with smaller numbers in Sofia City, Varna, Vidin, Sofia region, and Targovishte. The age distribution is heavily paediatric—231 of 364 cases (63%) in children under 10 years old, with the highest incidence (73 per 100,000) in infants under one year—and the vaccination status data are stark: of 331 cases with known status, 187 (56%) were unvaccinated. Over 39,799 MMR doses have been administered in outbreak response to date, indicating a substantial but evidently still-incomplete catch-up vaccination effort relative to the scale of ongoing transmission.
At the broader European level, the rolling twelve-month total (1 May 2025–30 April 2026) across 30 reporting countries reached 3,779 cases, of which 78.1% occurred in unvaccinated individuals and only 8.7% in those with two or more documented vaccine doses—a profile consistent with classic immunity-gap-driven transmission rather than vaccine failure. Three deaths were reported in this period (France, two; Netherlands, one). Outside the EU/EEA, the picture is similarly concerning in several jurisdictions of relevance to summer travel: Mexico (11,569 confirmed cases and 14 deaths in 2026 alone, with Jalisco state most affected), Canada (1,063 cases across seven jurisdictions with ongoing multijurisdictional transmission), and the United States (2,030 confirmed cases with 30 new outbreaks in 2026) are all flagged with specific reference to the forthcoming FIFA World Cup 2026, which will host large gatherings across all three countries during a period of active multi-jurisdictional measles transmission—a scenario ECDC explicitly highlights as warranting traveller vaccination status verification before departure. Given Bulgaria’s own substantial domestic outbreak, this confluence of sustained low population immunity and high case counts across multiple travel-linked jurisdictions reinforces the priority ECDC places on closing first- and second-dose MMR coverage gaps before the summer travel season intensifies.
Infectious Diseases: Bulgaria
Respiratory and Droplet Transmission
Measles
Regional ZRZ surveillance data show measles activity continuing in both reporting weeks, with district-level case counts of 15 in Week 23 (Vidin 1, Vratsa 3, Lovech 2, Montana 1, Pleven 7, Targovishte 1) and 24 in Week 24 (Vratsa 9, Lovech 6, Pleven 7, plus two further cases not individually attributed in the available breakdown), a 60% increase between the two weeks. As established in this report series and corroborated by ECDC’s monthly measles monitoring (discussed above), Bulgarian measles surveillance is structurally routed through the NCOZA/ZRZ district-level reporting system rather than the NCIPD national operational analysis, which records no measles activity for either week—a known reporting architecture rather than a genuine discrepancy, and a point that continues to merit explicit note given the risk of undercounting if NCIPD figures alone were used. The persistent concentration of cases in Vratsa, Lovech, and Pleven—three adjacent districts in northwestern and north-central Bulgaria—is consistent with ECDC’s independent confirmation that these three districts account for the substantial majority (340 of 364, or 93%) of the national outbreak’s cumulative caseload to date. Measles (Morbillivirus hominis) is transmitted via the respiratory and airborne route, with one of the highest basic reproduction numbers (R₀ 12–18) of any human pathogen, requiring sustained population immunity above 95% with two vaccine doses to interrupt transmission; the outbreak’s documented concentration in children under 10 years old, more than half of them unvaccinated, indicates the immunity gap remains substantial in the affected districts despite the more than 39,000 MMR doses administered in outbreak response nationally. Continued case-based investigation, vaccination status ascertainment, and catch-up immunisation in the three core districts remain warranted.
Scarlet Fever
Scarlet fever notifications declined sharply across both weeks: 58 cases in Week 23 (a 12-case, 26% increase from Week 22) followed by 46 cases in Week 24 (a 12-case, 21% decrease). The year-to-date cumulative total reached 1,589 cases by Week 24, a substantial 33% deficit relative to the 2,376 cases recorded in the same period of 2025, continuing a season that has tracked consistently below the prior year throughout its course. The Week 24 decline coincides with the end of the Bulgarian school year, consistent with scarlet fever’s transmission via respiratory droplets in congregate paediatric settings; the magnitude of the year-over-year deficit, sustained across multiple months now, suggests a genuine reduction in transmission intensity for the 2026 season rather than a reporting artefact, though the underlying driver (whether reduced Streptococcus pyogenes circulation, improved case management, or another factor) is not elucidated by routine surveillance data alone.
Varicella
Varicella registered 546 cases in Week 23 (a 58-case, 12% increase from Week 22) followed by a marked 384 cases in Week 24 (a 162-case, 30% decrease), with the year-to-date cumulative total of 14,238 cases remaining only marginally above the 14,162 cases recorded in the same period of 2025 (+0.5%). The Week 24 decline, like that observed for scarlet fever, is consistent with the close of the school term reducing opportunities for transmission in the congregate settings that typically sustain varicella circulation in school-aged children; the broadly flat year-over-year trajectory across the cumulative season indicates 2026 has tracked closely with 2025 despite week-to-week volatility. Sofia-grad remains the largest single contributor in both weeks (185 in Week 23, 94 in Week 24), reflecting both population size and the concentration of paediatric care-seeking in the capital.
Fecal-Oral Transmission
Gastroenteritis and Enterocolitis
Acute gastroenteritis and enterocolitis registered 173 cases in Week 23 (a 61-case, 54% increase from Week 22) followed by 153 cases in Week 24 (a 20-case, 12% decrease), with the cumulative year-to-date total of 3,624 cases by Week 24 modestly exceeding the 3,575 cases recorded in the same period of 2025 (+1.4%). The Week 23 surge—comprising a substantial proportion of possible and probable rather than laboratory-confirmed cases (74 possible and 94 probable of 173 total)—is consistent with the early-summer rise in foodborne and waterborne transmission risk associated with rising ambient temperatures, though the subsequent Week 24 partial reversal suggests this was not the start of a sustained upward trajectory. The persistently high ratio of possible/probable to confirmed cases across both weeks reflects the syndromic nature of gastroenteritis surveillance in Bulgaria, which captures clinical presentations without systematic aetiological confirmation; this limits the ability to distinguish viral, bacterial, or mixed-source outbreaks from routine surveillance data alone.
Vector-Borne Transmission
Lyme Borreliosis
Lyme borreliosis registered 14 cases in Week 23 (a three-case, 27% increase from Week 22) followed by nine cases in Week 24 (a five-case, 36% decrease), with the year-to-date total of 105 cases by Week 24 now 18 cases (15%) below the 123 cases recorded in the same period of 2025—a modest but notable reversal from the excess pattern documented in this report series through the earlier weeks of the tick season. Borrelia burgdorferi sensu lato, transmitted by Ixodes ricinus, typically presents with erythema migrans in the majority of cases, with disseminated neurological, cardiac, or articular involvement in untreated infection; the current below-baseline trajectory should be interpreted cautiously given the still-early stage of peak tick season, and continued surveillance through July will clarify whether 2026 is genuinely tracking below 2025 or whether this reflects short-term reporting variation.
Contact and Sexual Transmission
Gonorrhea
Gonorrhea registered five cases in Week 23 (unchanged from Week 22) followed by zero cases in Week 24 (a five-case decrease). Despite this single-week absence of new cases, the year-to-date cumulative total of 111 cases by Week 24 remains 178% above the 40 cases recorded in the same period of 2025, sustaining the most pronounced year-over-year excess among tracked sexually transmitted infections in Bulgaria for the 2026 surveillance year, consistent with the pattern documented throughout this report series. As previously noted, routine Bulgarian gonorrhea surveillance does not capture antimicrobial susceptibility data, a structurally significant limitation given the global context of emerging extensively drug-resistant Neisseria gonorrhoeae and the clinical consequences of undetected treatment failure.
Urogenital Chlamydial Infection
Urogenital chlamydial infection registered nine cases in Week 23 (a three-case, 50% increase from Week 22) followed by five cases in Week 24 (a four-case, 44% decrease), with the year-to-date cumulative total of 164 cases by Week 24 representing a 148% excess over the 66 cases recorded in the same period of 2025. Chlamydia trachomatis, the most frequently reported bacterial sexually transmitted infection in the EU/EEA, is commonly asymptomatic—particularly in women—leading to systematic surveillance undercounting irrespective of true incidence; the sustained, large year-over-year excess documented across 2026 likely reflects some combination of genuine transmission increase, expanded testing access, and improved case ascertainment, a combination that cannot be disentangled using routine notification data alone.
Syphilis
Syphilis registered 11 cases in Week 23 (a six-case, 120% increase from Week 22) followed by six cases in Week 24 (a five-case, 45% decrease), with the year-to-date cumulative total of 185 cases by Week 24 now 21% above the 153 cases recorded in the same period of 2025. Congenital syphilis, tracked separately, added one further case in each week, bringing the year-to-date total to 19 cases against 13 in the same period of 2025 (+46%)—a continued, modest but persistent burden of vertically transmitted infection that, unlike adult syphilis, is entirely preventable through adequate antenatal screening and treatment, making this trend a specific marker of gaps in maternal care access or screening completeness rather than broader community transmission dynamics.