'Evidence for waterborne origin of an extended mixed gastroenteritis outbreak in a town in Northern Greece, 2019'.

We investigated a large gastroenteritis outbreak that occurred in Northern Greece in 2019. A case was defined as anyone presenting with diarrhoea and/or vomiting from 24 January 2019 to 04 February 2019. We conducted a case-control study (CCS) using random selection of participants >16 years of age, residents of town X, who visited the health care centre between 25 and 28 January 2019. Moreover, we conducted a retrospective cohort study (CS) at the four elementary schools of the town. We collected clinical and water samples and the water supply system was inspected. In total, we recorded 638 cases (53% female; median age was 44 years (range 0-93)). Forty-eight cases and 52 controls participated in the CCS and 236 students in the CS. Both CCS and CS indicated tap water as the most likely source (OR 10, 95% CI 2.09-93.4, explaining 95.7% of cases; RR = 2.22, 95% CI 1.42-3.46, respectively). More than one pathogen was detected from stool samples of 6 of the 11 cases tested (norovirus, Campylobacter jejuni, Enterohemorrhagic E. coli (EHEC) and Enteropathogenic E. coli (EPEC)). Water samples, collected after ad-hoc chlorination, tested negative. Technical failures of the water tanks' status were identified. Our results suggested a waterborne outbreak. We recommended regular monitoring of the water supply system and immediate repair of technical failures.

A patient with respiratory toxigenic diphtheria in Greece after more than 30 years.

The introduction of treatment and systematic vaccination has significantly reduced diphtheria mortality; however, toxigenic strains continue to circulate worldwide. The emergence of an indigenous diphtheria case with fatal outcome in Greece, after 30 years, raised challenges for laboratory confirmation, clinical and public health management. Toxigenic Corynebacterium diphtheriae was isolated from an incompletely vaccinated 8-year-old boy with underlying conditions. The child passed away due to respiratory distress syndrome, before the administration of diphtheria antitoxin (DAT). All close contacts in family, school and hospital settings were investigated. Pharyngeal swabs were obtained to determine asymptomatic carriage. Chemoprophylaxis was given for 7 days to all close contacts and a booster dose to those incompletely vaccinated. Testing revealed a classmate, belonging to a subpopulation group (Roma), and incompletely vaccinated, as an asymptomatic carrier with an indistinguishable toxigenic strain (same novel multilocus sequence type, designated ST698). This case highlights the role of asymptomatic carriage, as the entry of toxigenic strains into susceptible populations can put individuals and their environment at risk. Maintenance of high-level epidemiological and microbiological surveillance, implementation of systematic vaccination in children and adults with primary and booster doses, availability of a DAT stockpile, and allowing timely administration are the cornerstone to prevent similar incidents in the future.

Epidemiology of hepatitis A in Greece in the last decade: management of reported cases and outbreaks and lessons learned.

Hepatitis A is a mandatory notifiable disease in Greece. Here, we present the epidemiological data for 2009-2018 and the results of outbreak investigations performed, and discuss future public health priorities.Overall, 1193 cases were reported; 320 migrants/refugees, 240 Roma, 112 travellers and 521 from the general population. The median age of the affected general population (37 years) had an increasing trend (from 30.8 years in 2009 to 40.5 in 2018, P < 0.001) and was significantly higher than that among Roma and migrants (7 and 8 years, respectively, P < 0.001). Twenty-two cases (2.2%) were unvaccinated patients with a chronic liver disease. Fifty clusters with 2-12 cases each were recorded; 44 were attributed to person-to-person transmission and six to food consumption. Three outbreaks accounting for 32.3% of the total number of recorded cases were identified; in 2013 among Roma (112 cases), in 2016 among refugees (188 cases) and in 2017 among men having sex with men (96 cases; 33 of them (34.4%) HIV-positive). The epidemiological data depict that improving living conditions and vaccination coverage of deprived populations, and informing adults on the disease focusing at faecal-oral transmission during sexual intercourse and travel should be the future public health priorities.

Brucellosis underreporting in Greece: assessment based on aggregated laborato-ry data of culture-confirmed cases from public hospitals.

BACKGROUND: Brucella spp. isolation is one of the mainstays of brucellosis diagnosis. Simultaneously, the true brucellosis disease rate may be underrepresented in notification systems. This study aims at assessing the nosocomial capacity for Brucella spp. isolation and the underreporting rate of brucellosis cases in Greece. METHODS: Data for Brucella spp. culture capacity and the number of isolations were collected annually from public hospitals nationwide, during 2015-2018. The number of unreported cases was estimated after subtracting the National Mandatory Notification System cases from the survey-captured isolations, matched by hospital and year. RESULTS: Feedback was provided by 112 public hospitals (response rate: 97.4 %). Brucella spp. isolation capacity was completely absent in 27.7 % of hospitals; during the four years of the study, 11.3 %, 13.9 %, 20.0 %, and 25.2 % of the hospitals had isolation competence for one, two, three, or four years, respectively. Underreporting assessment was possible in hospitals that declared at least one Brucella spp. isolation (n =35) and unreported cases were identified in 19 (54 %). Α mean underreporting of 28.9 % of total cases was estimated for the whole period of the study ranging annually from 24.1 % to 35.0 %. The number of unreported cases per hospital ranged from one to 12 per year (median: 2, IQR: 5). CONCLUSIONS: Interventions for improving diagnosis and reporting of the disease are recommended. Assessment of brucellosis underreporting by comparing raw numerical data of survey-captured isolations and officially notified cases lacks the case by case specificity, however, keeping required data to a minimum achieves high feedback rate from hospitals and provides a tentative estimation of the notification deficit. HIPPOKRATIA 2019, 23(3): 106-110.

Laboratory capacity of Greek hospitals for diagnosis of salmonellosis and surveillance systems' performance in the years of economic crisis, 2010-2016.

Austerity might have affected the capacity of public hospitals in Greece to diagnose salmonellosis (laboratory capacity) over the period 2010-2016, as well as the performance of the existing surveillance systems. The scope of this paper is to present data on laboratory capacity over these years, as well as the results of a two-source capture-recapture study (data from Mandatory Notification System and National Reference Laboratory System for Salmonella). The main findings were that: (a) laboratory capacity was high and steady besides the financial crisis, (b) the estimated number of laboratory-confirmed cases (n = 6017, 95% CI 5892-6142) resulted in an incidence rate (7.9 cases/100 000 population) almost twice than that reported by the two systems Mandatory Notification System (MNS); 4.1 and National Reference Laboratory System (NRLS); 4.5 cases/100 000 population, (c) underreporting was high for both systems (MNS; 47.5% and NRLS; 42.8%) and (d) differences by geographical region, size and type of hospital were identified. We suggest that (a) specific interventions are needed to increase completeness of the systems by type of hospital and geographical region, (b) record linkage can help in estimating the disease burden in a more valid way than each system separately and (c) a common electronic database in order to feed one system to the other could significantly increase completeness of both systems.

Ongoing measles outbreak in Greece related to the recent European-wide epidemic.

We report an ongoing measles outbreak in Greece. The first cases were notified through the mandatory notification system on May 2017 in Northern Greece and concerned a cluster of three imported cases in unvaccinated Roma siblings. So far, 3150 cases have been reported in all 13 Regions. Initially, the outbreak mainly affected Greek Roma but as it progressed it spread to non-minority Greek nationals. The outbreak reached its ultimate peak on week 10/2018 but from week 15/2018 has been gradually declining. Most cases (60.6%) were Roma (especially children <10 year-old) followed by non-minority Greek nationals (29.3%; mostly young adults). The majority (80.4%) were unvaccinated. Interestingly, 129 (4.1%) cases were healthcare workers (HCWs). Genotype B3 was identified by molecular methods in all 87 cases tested. Overall, 61.3% of the cases were hospitalised. Complications were reported in 17.1% of the cases among which four deaths. The outbreak occurred after 3 years without local endemic measles transmission. Extensive vaccination implemented as the major public health measure managed to prevent the emergence of a large number of cases in refugee/migrant hosting sites. Mitigation efforts currently focus on raising awareness among HCWs and closing the immunisation gap in populations with suboptimal vaccination coverage.

A severe gastroenteritis outbreak of Salmonella enterica serovar Enteritidis PT8, with PFGE profile XbaI.0024 and MLVA profile 2-9-7-3-2 following a christening reception, Greece, 2016.

In June 2016, a Salmonella enterica serovar Enteritidis outbreak (n = 56) occurred after a christening reception in Central Greece, mainly affecting previously healthy adults; one related death caused media attention. Patients suffered from profuse diarrhoea, fever and frequent vomiting episodes requiring prolonged hospitalisation and sick leave from work, with a 54% hospital admission rate. The majority of cases experienced serious illness within <12 h of attending the party. We investigated the outbreak to identify the source(s) of infection and contributing factors to the disease severity. From the retrospective cohort study, the cheesy penne pasta was the most likely vehicle of infection (relative risk 7·8; 95% confidence interval 3·6-16·8), explaining 79% of the cases. S. enterica ser. Enteritidis isolates were typed as phage-type PT8, pulsed-field gel electrophoresis type XbaI.0024, multiple locus variable-number tandem repeat analysis-type 2-9-7-3-2. The strain did not share the single-nucleotide polymorphism address of the concurrent European S. enterica ser. Enteritidis PT8 outbreak clusters. Following five consecutive years with no documented S. enterica ser. Enteritidis outbreaks in Greece, this outbreak, likely associated with a virulent strain, prompted actions towards the enhancement of the national Salmonella molecular surveillance and control programmes including the intensification of training of food handlers for preventing similar outbreaks in the future. Advanced molecular techniques were useful in distinguishing unrelated outbreak strains.

Ιnfluenza A(H3N2) genetic variants in vaccinated patients in northern Greece.

BACKGROUND: Influenza A(H3N2) viruses predominated during the influenza 2016/2017 season and showed extensive genetic diversification. A high vaccination failure rate was noticed during the 2016/17 season in Greece, especially among the elderly. OBJECTIVES: The scope of the study was to investigate the genetic characteristics of A(H3N2) circulating viruses and viruses detected in vaccinated patients. STUDY DESIGN: Virus samples originated from vaccinated and unvaccinated patients, obtained at the National Influenza Centre for northern Greece. Phylogenetic analysis and comparison of the haemagglutinin gene of the viruses to the vaccine virus A/Hong Kong/4801/2014 was performed. RESULTS: The majority of analysed viruses are clustering in the genetic clade 3C.2a, and in a newly emerged subclade, designated as 3C.2a1. The highest proportion of viruses detected in vaccinated patients fell into a distinct subcluster within the 3C.2a1 subclade, which is characterised by the amino acid substitutions N122D and T135K in haemagglutinin. CONCLUSIONS: Viruses that belong to the 3C.2a clade are generally considered to resemble antigenically to the northern hemisphere vaccine component A/Hong Kong/4801/2014 that was recommended by WHO to be included also into the 2017/18 vaccine. However, viruses belonging to a specific 3C.2a1 subcluster was extensively circulating in northern Greece and among vaccinated individuals. Both substitutions carried by this strain were located on antigenic sites and caused losses of N-linked glycosylation sites of the virus, which could potentially affect viral antigenicity. Further studies are needed to determine the antigenicity of this variant strain and its possible implication in vaccine effectiveness.

Pilot study of the completeness of notification of adult tuberculosis in Athens, Greece.

SETTING: Sotiria Chest Diseases Hospital (SCDH), a referral hospital in Athens, Greece, 2012. OBJECTIVE: To assess the completeness of the mandatory notification system for tuberculosis (TB) at the SCDH, and compare the observed and estimated annual incidence rates. DESIGN: Record linkage and the capture-recapture method were applied. Data sources were the registers from the national mandatory notification register (Hellenic Centre for Disease Control and Prevention [HCDCP]), the National Reference Laboratory for Mycobacteria (NRLM) and SCDH records. The log-linear model with the lowest Akaike information criterion was selected as the most valid statistical model. RESULTS: The observed and estimated TB under-reporting rates at the national level were respectively 55% (95%CI 49-60) and 75% (95%CI 71-78). The observed completeness of the HCDCP, NRLM and SCDH registers were respectively 45% (95%CI 40-51), 66% (95%CI 61-71) and 36.5% (95%CI 31-42). The estimated TB incidence rate was 15 cases per 100 000 (range 13-19/100 000), compared to the 4.9/100 000 rate officially notified. CONCLUSION: Adult TB incidence has been largely underestimated, and the TB burden is likely to be much higher than officially notified in our setting. A thorough review of the notification system should be carried out. The implementation of a network-based notification system and retraining of all relevant personnel is advised.

Resistant Shigella strains in refugees, August-October 2015, Greece.

Shigellosis is endemic in most developing countries and thus a known risk in refugees and internally displaced persons. In 2015, a massive influx of refugees into Greece, due to the political crisis in the Middle East, led to the development of appropriate conditions for outbreaks of communicable diseases as shigellosis. We present a cluster of 16 shigellosis cases in refugees, detected by the implementation of a syndromic notification system in one transit centre in Athens, between 20 August and 7 October 2015. Both Shigella flexneri (n = 8) and S. sonnei (n = 8) were identified, distributed in various serotypes. All tested isolates (n = 13) were multidrug resistant; seven were CTX-M-type extended-spectrum ß-lactamase producers. Our results indicate lack of a potential common source, although pulsed-field gel electrophoresis typing results revealed small clusters in isolates of the same serotype indicating possible limited person-to-person transmission without identifying secondary community cases related to the refugees. To prevent the spread of shigellosis, empirical antibiotic treatment as well as environmental hygiene measures were implemented. The detection of multi-drug resistance is important for determining the appropriate empirical antibiotic treatment for the more severe cases, while at the same time real-time typing is useful for epidemiological investigation and control measures.

A large waterborne gastroenteritis outbreak in central Greece, March 2012: challenges for the investigation and management.

In March 2012, there was an unusual increase of gastroenteritis cases in a district with 37,264 inhabitants in central Greece. It was estimated that more than 3600 people developed symptoms. A 1:1 case-control study showed that consumption of tap water was a risk factor for acquiring infection [odds ratio (OR) 2.18, 95% confidence interval (CI) 1.11-4.28]. Descriptive data, low gastroenteritis incidence in adjacent areas with different water supply systems, and water-quality data further supported the hypothesis of a waterborne outbreak. Thirty-eight stool samples were positive for rotavirus. Bacterial indicators of recent faecal contamination were detected in samples from the water source and ice cubes from a local production enterprise. Molecular epidemiology of rotavirus strains, apart from the common strain, G3[P8], identified the unusual G/P combination G2P[8]. Water sanitation measures contributed to the control of the outbreak. This outbreak demonstrated the need for the cooperation of laboratories with different expertise and the importance of early notification of waterborne gastroenteritis outbreaks.

Management and investigation of viral gastroenteritis nosocomial outbreaks: lessons learned from a recent outbreak, Greece, 2012.

BACKGROUND: A nosocomial outbreak in a 740-bed hospital in Athens, Greece, was investigated in January-February 2012. METHODS: Recommendations on infection control measures were given and two case-control studies were conducted among patients (study A) and health care workers (HCWs) (study B). Compliance to control measures was evaluated. RESULTS: The absence of a routine recording system of nosocomial-acquired gastroenteritis cases led to a 10 days delay in outbreak identification. In total, 63 gastroenteritis cases were identified; 30 HCWs and 33 patients. In the multivariable analysis of study A the disease incidence among patients was statistical significantly associated with a prior incident of vomitus in their room (OR=7.96, 95% CI=1.29-49.2). In study B, the incidence was associated with the history of direct contact with a symptomatic patient (OR=3.03, 95%CI 1.01-9.12). Twenty one (75%) of the symptomatic HCWs reported absence from work for a median of 2 days (range: 1-4). Seven (25.0%) continued to work despite being symptomatic. Only, 11.1% of patients were isolated or cohorted after developing symptoms. In-hospital virological testing was not feasible and one specimen sent to a university laboratory was positive for norovirus. CONCLUSIONS: An appropriately designed protocol regarding the detection, the management and the laboratory investigation of nosocomial gastroenteritis outbreaks should be followed in order effective containment to be reassured. Hippokratia 2014; 18 (3): 204-208.

Epidemiology of human leishmaniasis in Greece, 1981-2011.

Leishmaniasis is endemic and mandatorily notifiable in Greece. Epidemiological surveillance data for leishmaniasis in Greece between 1981 and 2011 are presented. In 1998, the notification system began distinguishing between visceral and cutaneous leishmaniasis. The mean annual incidence of reported leishmaniasis cases between 1998 and 2011 was 0.36 per 100,000 population. Of a total 563 leishmaniasis cases reported after 1998, 523 (93%) were visceral leishmaniasis cases. Incidence of reported visceral leishmaniasis cases fluctuated during this period, generally decreasing after 2007, with a small re-increase in 2011. The mean annual incidence rate of reported visceral leishmaniasis cases was significantly higher in less than four year-olds (p <0.001). Leishmaniasis cases occurred both in the country mainland and islands. Between 1998 and 2011, Attica concentrated almost half of the reported visceral leishmaniasis cases, with incidence rates in western Attica and western Athens above 12.00 per 100,000 population. Compared to visceral leishmaniasis, cutaneous leishmaniasis had a rather sporadic distribution, with many prefectures appearing free of cases. From 2004, the notification also included risk factors and of 287 cases with known immune status, 44 (15%) were immunocompromised. Moreover having a dog at home was reported by 209 of 312 leishmaniasis cases (67%), whereas 229 of 307 cases (75%) reported the presence of stray dogs near their residence. Linking clinical surveillance data with laboratory data and improving collaboration with the veterinary public health sector are some of the future challenges for leishmaniasis surveillance in Greece.

Re-emergence of animal rabies in northern Greece and subsequent human exposure, October 2012 - March 2013.

Greece has been rabies-free since 1987 with no human cases since 1970. During 2012 to 2013, rabies has re-emerged in wild and domestic animals in northern Greece. By end March 2013, rabies was diagnosed in 17 animals including 14 red foxes, two shepherd dogs and one cat; 104 subsequent human exposures required post-exposure prophylaxis according to the World Health Organization criteria. Human exposures occurred within 50 km radius of a confirmed rabies case in a wild or domestic animal, and most frequently stray dogs were involved.

Socioeconomic factors play a more important role in childhood vaccination coverage than parental perceptions: a cross-sectional study in Greece.

To identify predictive factors of complete and age-appropriate vaccination status in Greece, we conducted a cross-sectional study, using stratified cluster sampling, among children attending the first year of the Greek Grammar school (about 6 years of age) and their parents/guardians. Almost 88% (N=3878) of pupils in the selected clusters (school classrooms) provided their vaccination booklet and their parents/guardians completed a questionnaire regarding beliefs and attitudes towards immunization. Belonging to a minority group, having other siblings and perceiving long distance to immunization site as a barrier were independent predictors of both incomplete and delayed vaccination status in the final logistic regression model. Maternal age >or=30 years and the perception that natural disease is preferable to vaccination were associated with complete vaccination, whereas paternal education of high school or higher was the other independent determinant of age-appropriate immunization. Socioeconomic factors rather than parental beliefs and attitudes towards immunization explained underimmunization. Further interventions are warranted to enhance vaccine coverage in high-risk groups identified in this study.

Epidemiology of rubella and congenital rubella syndrome in Greece, 1994-2003.

In 1993, there was a large epidemic of rubella and congenital rubella syndrome (CRS) in Greece. The epidemiology of rubella and CRS after 1993 is described in this paper using information from surveillance data and published studies and reports. The incidence of rubella fell sharply after 1993, but a smaller outbreak occurred in 1999, mainly in young adults, and four CRS cases (4.0 per 100,000 live births) were recorded. A very high proportion of the child population in Greece are currently vaccinated for rubella, while teenagers are inadequately covered (60-80% in different studies). A substantial proportion of women of childbearing age are susceptible to rubella (10-20% in urban areas). This could lead to local or more extended outbreaks. This situation shows that a comprehensive preventive policy should be implemented.

Epidemiology of rubella and congenital rubella syndrome in Greece, 1994-2003.

In 1993, there was a large epidemic of rubella and congenital rubella syndrome (CRS) in Greece. The epidemiology of rubella and CRS after 1993 is described in this paper using information from surveillance data and published studies and reports. The incidence of rubella fell sharply after 1993, but a smaller outbreak occurred in 1999, mainly in young adults, and four CRS cases (4.0 per 100 000 live births) were recorded. A very high proportion of the child population in Greece are currently vaccinated for rubella, while teenagers are inadequately covered (60-80% in different studies). A substantial proportion of women of childbearing age are susceptible to rubella (10-20% in urban areas). This could lead to local or more extended outbreaks. This situation shows that a comprehensive preventive policy should be implemented.