Georgios Dougas

Background: In September 2023, catastrophic flooding from storms Daniel and Elias struck Thessaly, Greece. We present findings from the postflood leptospirosis outbreak investigation and key lessons for future preparedness. Methods: Ad hoc active surveillance was set up to complement national notifications. We used the national case definition for leptospirosis probable and confirmed cases. Diagnostic protocols involved clinical manifestation, polymerase chain reaction (PCR), targeted sequencing (blood/urine,) and serology. Exposure history was collected via a structured questionnaire. We performed case-series analyses, logistic regression, and receiver operating characteristic curve analysis. Results: During the 3-month postflood period, 285 probable and 45 confirmed leptospirosis cases were identified. The postflood notification rate was 6.5/100 000 population. Leptospira kirschneri and Leptospira interrogans were identified in 33 (87%) and 5 (13%) of the 38 PCR-confirmed cases, respectively. Two deaths were attributed to L interrogans. Patients with L interrogans had higher odds of hospitalization (odds ratio, 16 [95% confidence interval, 1.6–159.2]), elevated creatinine (P = .03) and urea (P = .03), and lower platelet counts (P = .02). Urine PCR had the highest diagnostic yield (84%). Patients with leptospirosis reported exposure to floodwater (89%), lack of strict adherence to personal protective equipment (100%), and limited awareness of protective measures (25%). Conclusions: The 2023 Thessaly floods led to a marked rise in leptospirosis incidence, with L interrogans linked to greater clinical severity. The outbreak highlights the need for public and healthcare workers’ awareness, early diagnosis, species-specific active surveillance, and One Health strategies. Strengthening multisectoral preparedness is critical as climate change increases the risk of similar events in Europe.

Leptospirosis is a zoonotic disease caused by spirochetes of the genus Leptospira, primarily transmitted via direct or indirect contact with contaminated rodent urine. Human disease ranges from a mild, flu-like illness to severe, life-threatening Weil’s disease. Although the incidence of leptospirosis in Greece is not high, the Ionian Islands Region, including Corfu Island, presents the highest average frequency of cases in the country. A retrospective study of 11 confirmed cases in Corfu between 2015 and 2025 was conducted. The infections recorded during this period occurred from autumn to spring, exclusively affecting male patients in rural settings; notably, 90.9% of cases were attributed to occupational exposure. No association with urban or tourist areas was found. Although the incidence of the disease decreased by 42.1% compared to the previous decade (2005–2014), the case fatality ratio reached 27.3%, considerably above the average of 2.6% in Europe (during 2010–2022). The study underscores the need for enhanced clinical awareness and targeted preventive measures in Corfu, mainly among patients with at-risk occupations. Timely preparedness is needed especially in the face of ongoing climate change.

Background: The present study investigated the microbiome of dissected cat flea heads for bacteria with clinical relevance for human infections. Methods: A total of 112 cat fleas (Ctenocephalides felis) were collected from 30 cats in Attica, Greece. The heads of the insects were aseptically dissected, pooled in groups by host ani-mals and analyzed with Ion Torrent 16S rRNA metagenomic sequencing. Results: Of the 1578 bacterial species detected, 119 (7.5 %) are known human pathogens. These include the classic flea-borne agents Bartonella henselae, B. clarridgeiae, and B. gra-hamii. Most pathogens (89 species, 74.8 %) can cause both bloodstream and skin or soft-tissue infections. Ten species are linked to bacteremia of unknown origin; among these, Haemophilus influenzae, Salmonella enterica, and Streptococcus pyogenes are typically associated with community-onset infections, whereas Enterococcus faecalis, Escherichia coli, Proteus mirabilis, and Staphylococcus aureus display varied epidemiological profiles related to both community-acquired and hospital-acquired bacteremias. Conclusions: The head microbiome of C. felis is exceptionally diverse and includes nu-merous bacteria of clinical importance. While the presence of DNA alone does not prove vector competence, the combination of biofilm capacity and the flea’s haematophagous behaviour supports a plausible—yet unproven—role of fleas in the transmission of un-conventional bacterial infections.

Introduction: The Epizootiological Investigation Form (EIF) is a document issued for every notified human brucellosis case, with the aim to convey information from public health to veterinary authorities for farm animals epidemiologically linked with the patient. We assessed the integration of EIF to the routine collaboration among stakeholders and the efficiency in directing the veterinary efforts to identify Brucella -infected animals. Methods: EIFs were evaluated for the implementation, timeliness, and completeness of the shared information provided by the public health and the veterinary authorities. The efficiency of EIFs in identifying infected farms was compared with the Brucella infection rate of routinely screened farms in the frame of the national brucellosis program. Results: During 2017–2022, 344 EIFs were issued for equal number of human brucellosis cases and 118 (34.3%) were circulated successfully among all stakeholders, whereas 226 (65.7%) went missing. The highest rate of intersectoral circulation occurred in May (47.8%, p = 0.007). Veterinary investigation was performed, and result was provided in 62 (57.4%) of the 108 circulated EIFs that disclosed the contact details of the epidemiologically linked animal farms. Brucella was detected at a significantly higher rate (51.7%) in the investigated sheep and goats' farms than the infection rate (2.7%) of the national brucellosis program ( p < 0.00001). Among the screened bovine herds, two were found infected of the eight tested (25%). The circulation among all competent authorities of EIFs with a farm screening outcome required a median (interquartile range) of 50 days (22, 88). The likelihood of a “complete” EIF per human case differed among geographic Regions ( p = 0.010), and was higher for patients diagnosed in April ( p = 0.001) and occupied as stockbreeders ( p = 0.025). Conclusions: EIF is a useful tool for pinpointing suspected animals for brucellosis screening. Training of the collaborating personnel is essential for improving the implementation of EIF in the everyday practice.

Shortwave and microwave diathermy devices are commonly used in physical therapy as heating treatment. The rise in temperature occurs due to the flow of electric current in the treated area. Ions are evenly distributed in a predicted pattern from skin to deeper tissues. We hypothesise that the diathermy physiotherapy devices (DPDs) can be repurposed as a means of neutralisation of the Rabies virus (RABV) by exploiting the generated electric charges. In order to minimise the ohmic heating of the tissue, the pulsed output of the diathermy devices is preferred where the ‘on’ time of active energy emission is considerably shorter than the ‘off’ time. RABV proteins mediating cell invasion, cytoplasmic replication and budding, contain polar components that can be adversely affected by non-thermal electric phenomena. Repurposed DPDs can replace the Rabies immunoglobulin (RIG) by targeting the site of inoculation i.e. the area of the animal bite, provided that the delivered electric charges can reduce pathogenicity by altering key viral proteins. The modality is advantageous compared to conventional RIG since it can theoretically neutralise all Lyssavirus species, is not limited by the compartment syndrome, can intercept RABV even after it gains access to the peripheral neural network where conventional post-exposure prophylaxis is ineffective and is cost-effective in the long term. The principle of physical alteration of vulnerable proteins by electricity delivered by electromagnetic radiation is not limited to RABV, but may be applied to a spectrum of viral pathogens.

In this study, the vaccination coverage, serological sampling and infection rate of sheep and goats were evaluated as predictors for the modeling of human brucellosis in Greece. The human brucellosis disease frequency per local regional unit (RU) varied significantly (RR90) among consecutive years. The notification rate was higher (p < 0.001) in the RUs with implementation of vaccination in sheep and goats (vaccination zone—VZ) with a median of 1.4 (IQR 0.0–3.1) compared with the RUs of the eradication zone (EZ) with a median of 0.0 (IQR 0.0–0.0). In VZ, the increased frequency of human cases was associated with delayed vaccine administration (estimate: 0.14 (0.04; 0.29), p = 0.03) and higher vaccination coverage of the animals (estimate: −0.349 (−0.72; −0.07), p < 0.01). However, the flock sampling rate was highly heterogenous among RUs (IQR 10.56–52.93), and inconsistent within RUs throughout the period of the study 2013–2017 (p = 0.001), limiting the reliable estimation of the infection rate in livestock and the design of an integrated One Health model for human disease.

The internal microbiome of common cat and dog fleas was studied for DNA evidence of pathogenic bacteria. Fleas were grouped in pools by parasitized animal. DNA was extracted and investigated with 16S metagenomics for medically relevant (MR) bacteria, based on the definitions of the International Statistical Classification of Diseases and Related Health Problems (WHO). The MR bacterial species totaled 40, were found in 60% of flea-pools (N = 100), and included Acinetobacterbaumannii, Bacteroidesfragilis, Clostridiumperfringens, Enterococcusfaecalis, E. mundtii, Fusobacteriumnucleatum, Haemophilusaegyptius, Kingellakingae, Klebsiellapneumoniae, Leptotrichiabuccalis, L. hofstadii, Moraxellalacunata, Pasteurellamultocida, Propionibacteriumacnes, P. propionicum, Proteusmirabilis, Pseudomonasaeruginosa, Rickettsiaaustralis, R. hoogstraalii, Salmonellaenterica, and various Bartonella, Staphylococcus, and Streptococcus species. B. henselae (p = 0.004) and B. clarridgeiae (p = 0.006) occurred more frequently in fleas from cats, whereas Rickettsiahoogstraalii (p = 0.031) and Propionibacteriumacnes (p = 0.029) had a preference in fleas from stray animals. Most of the discovered MR species can form biofilm, and human exposure may theoretically occur through the flea-host interface. The fitness of these pathogenic bacteria to cause infection and the potential role of fleas in the transmission of a broad range of diseases should be further investigated.

Rickettsia typhi and Bartonella henselae are the causative agents of murine typhus and cat-scratch disease, respectively. A small-scale survey (N = 202) was conducted in the Attica region, Greece, for determining the prevalence rates of IgG antibodies against B. henselae and R. typhi by indirect fluorescence antibody test. IgG against B. henselae and R. typhi were present in 17.8% (36/202) and 4.5% (9/202) of the participants, respectively; co-occurring IgG against both B. henselae and R. typhi were detected in 3.5% (7/202), whereas only anti-B. henselae IgG in 14.3% (29/202), and only anti-R. typhi IgG in 1.0% (2/202). Titres 1/64, 1/128, 1/256, and 1/512, of anti-B. henselae IgG were identified in 6.4%, 4.5%, 4.5%, and 2.4%, whereas titres 1/40 and 1/80 of anti-R. typhi IgG were detected in 4.0%, and 0.5%, respectively. A positive association of anti-B. henselae IgG prevalence with a coastal area featuring a major seaport (p = 0.009) and with younger age (p = 0.046) was identified. The findings of this survey raise concern for exposure of the population of Attica to B. henselae and R. typhi, which should be considered in the differential diagnosis when compatible symptoms are present. Our results also suggest that seaports may represent high-risk areas for exposure to Bartonella spp.