SURVEILLANCE OF FOODBORNE DISEASE OUTBREAKS ASSOCIATED WITH CONSUMPTION OF EGGS AND EGG PRODUCTS : SPAIN , 2002 – 2003

The screening project The project first analysed current chlamydia epidemiology in the Region. With the participation of regional primary care level gynaecologists, 1000 female patients aged 18-30 years are being screened. Because all women must register to use gynaecology services, there is precise information on the number of women within certain age categories. There are 4700 registered women aged 18-24 years and 4456 registered women aged 25-30 years. From this, we estimated that a sample of 1000 would be realistically achievable within the short time period that the project is running. All women between the ages 18-30 years who consult gynaecologists in Nova Gorica region are being asked to participate in this project. If they agree, and give written informed consent, they are invited to provide a first void urine specimen for chlamydia testing. They are also asked to complete a short questionnaire on their social and demographic background and on their sexual behavioural [2]. On the basis of the FVU specimen test results, the prevalence of Chlamydia trachomatis urogenital infections in different age groups, and the sociodemographic and sexual behavioural risk factors for chlamydia urogenital infections can be estimated.


The screening project
The project first analysed current chlamydia epidemiology in the Region.With the participation of regional primary care level gynaecologists, 1000 female patients aged 18-30 years are being screened.
Because all women must register to use gynaecology services, there is precise information on the number of women within certain age categories.There are 4700 registered women aged 18-24 years and 4456 registered women aged 25-30 years.From this, we estimated that a sample of 1000 would be realistically achievable within the short time period that the project is running.
All women between the ages 18-30 years who consult gynaecologists in Nova Gorica region are being asked to participate in this project.If they agree, and give written informed consent, they are invited to provide a first void urine specimen for chlamydia testing.They are also asked to complete a short questionnaire on their social and demographic background and on their sexual behavioural [2].
On the basis of the FVU specimen test results, the prevalence of Chlamydia trachomatis urogenital infections in different age groups, and the sociodemographic and sexual behavioural risk factors for chlamydia urogenital infections can be estimated.

Diagnostic methods
Since 1986, direct fluorescent antibody (DFA) testing has been used to detect genital chlamydia infection in Nova Gorica.Project funding has obtained Mastercycler equipment which enables chlamydia detection by polymerase chain reaction (PCR); PCR is highly sensitive and is much more effective than DFA testing of individuals with asymptomatic infections.

Contribution to prevention work
Diagnosis, prevention and treatment of chlamydia require a multidisciplinary approach by health professionals.With the screening results, we aim to inform and promote screening of chlamydia infection among regional gynaecologists and affect public health policy on the issue.
Funding is provided through the Phare programme (http:// europa.eu.int/comm/enlargement/pas/phare/intro.htm), and one of the conditions of Phare funding is collaboration between European countries.This project is a collaboration with the Azienda per I Servizi Sanitari n. 2 "Isontina" Gorizia and Comune di Gorizia -Servizi Sociali in Italy, and leaflets giving information on genital chlamydia infection (symptoms, transmission, diagnosis, treatment, follow-up, prevention and safe sex) have been produced in both Slovene and Italian.These leaflets will be distributed in gynaecological dispensaries, schools, and to the media in Nova Gorica, Slovenia and the Gorizia region in Italy, with the intention of raising chlamydia awareness in young people.
The project started in October 2004 and is due to finish by October 2005.We hope that our results will provide support for the introduction of nationwide chlamydia screening in Slovenia.Foodborne disease outbreaks are a public health problem for certain population groups in Spain, because of their magnitude and severity [1].The foods implicated in these outbreaks tend to be prepared with raw shell eggs, and Salmonella serotype Enteritidis tends to be the causative agent.In Spain, foodborne outbreaks due to consumption of eggs and egg products have not declined since 1998 [2], despite the introduction of numerous prevention measures aimed at addressing this problem.Such measures include health education [3] and making it mandatory for food catering facilities that cook and/ or serve meals to replace raw shell eggs with pasteurised egg products when food is prepared without heat treatment and for immediate consumption [4].

Published
There are a number of sources that provide information for surveillance of foodborne diseases and outbreaks in Spain.The Outbreak Reporting System (Sistema de Brotes) and the National Reference Laboratory of Spain are the most useful for outbreaks specifically linked to consumption of eggs or egg products.The Outbreak Reporting System collects epidemiological data from the regions of Spain [5].The National Reference Laboratory shares data with other European countries via networks such as the International Surveillance Network for the Enteric Infections (Enter-net, http:// www.hpa.org.uk/hpa/inter/enter-net_menu.htm).
For this study, we analysed data on reported foodborne outbreaks in Spain associated with the consumption of eggs and egg products, for the period 2002 -2003 (the most recent complete years available for both sources).

Outbreak Reporting System
In Spain, a median of 951 (range: 882-989) foodborne outbreaks were reported in the 10 years preceding the study.In 2002 and 2003, the equivalent figures were 971 and 1227 outbreaks, respectively.
Outbreaks associated with consumption of eggs and egg products accounted for 41% of all foodborne disease outbreaks (895/2198), with a total of 6991 cases including 1059 hospital admissions and 6 deaths (Table 1).Although the number of foodborne disease outbreaks reported in 2003 rose overall, the percentage of these due to consumption of eggs and egg products was not notably different from that registered the previous year (40% in 2003 versus 42% in 2002).The Outbreak Reporting System data for 2003 indicated an increase over 2002 in terms of both the number of community and household outbreaks, and the number of cases (Table 1).In 2003, 57% of outbreaks were linked to the home, 38% were community outbreaks and, in 5% of outbreaks, the setting was not reported.Among the group of community outbreaks attention should be drawn to the food catering and handling sector, which accounted for 32% and 34% of all outbreaks, with a known setting in 2002 and 2003, respectively (Figure 1).Of the 895 outbreaks linked to consumption of eggs and egg products, 85% (758 outbreaks) were due to salmonella.Salmonella Enteritidis, with 438 outbreaks, accounted for 58% of salmonellas in these outbreaks; moreover, it is thought that this percentage would be higher still if the serotype in the 310 outbreaks due to salmonella species were known.The foodstuff implicated (eggs and egg products) was laboratory confirmed in 1.7% (15 outbreaks), epidemiologically confirmed in 39% (353 outbreaks), and by both in 8% of instances (74 outbreaks).There was evidence of contributing factors in 685 outbreaks (77%, 685/895), the most important being linked to unsafe food temperatures, consumption of raw foods, and preparation far in advance of consumption.Control measures are reported to have been implemented for 70% of these outbreaks (629/895).Figure 3 shows that the most important control measure was health education, followed by inspection of premises and the monitoring of food handlers.In 11 outbreaks, intervention led to closure of the facility, and in 4 outbreaks, to the imposition of penalties.Unlike the data from the Outbreak Reporting System, the data from the National Reference Laboratory indicated a marked decrease in the number of outbreaks across the two years studied (Table 1).A total of 54% (20/37) of these outbreaks took place in homes.The National Reference Laboratory of Spain obtained data on the suspected food in 34% of the outbreaks studied.The results yielded by this source pointed to eggs as being the suspected food in 12% of all salmonella outbreaks: nevertheless, if all outbreaks in which the suspected food was present were included, this percentage would rise to 62%.The Enteritidis serotype proved to be the causative agent in 89% (33/37) of outbreaks in which eggs were cited as the suspected food (Figure 4).Information was obtained on S. Enteritidis phage types in 32 egg-or egg-product-related outbreaks, with phage types 1 (13 outbreaks, 35% of the total) and 4 (6 outbreaks, 11% of the total) being identified most frequently.In the remaining 13 outbreaks, 7 different phage types were identified (21, 8, 6, 44, 4B, 1C and 7).

Reported foodborne outbreaks and cases associated with consumption of eggs and egg products, Spain: 2002-2003
This article was translated and adapted by the authors from reference 1.
Between December 2004 and March 2005, two cases of pertussis (whooping cough) in unvaccinated infants, both under two months of age, were reported to the same municipal health authority in the north of Portugal.These cases are part of a changing epidemiological pattern of infection due to Bordetella pertussis in Portugal.
The Portuguese national vaccination programme's recommended schedule includes five doses of diphtheria-tetanuspertussis [1,2] whole cell (DTPw) pertussis vaccine.The first dose is recommended at two months of age and the fifth at 5-6 years of age [1].Vaccine coverage in Portugal is high [3] and pertussis has been a statutorily reportable disease for many years.Reported cases of pertussis decreased since the 1960s and reached very low levels in the period 1993-2003 [4,5] (Table 1).In northern Portugal, fewer than 10 cases have been reported each year from 1993 to 2002 to zero cases in 2003; there was a clear resurgence in 2004, when 26 cases were reported (Table 1), with 2 deaths in children below 2 months of age.No deaths were reported from 2000 to 2003.Both in the north, and in Portugal as a whole, most reported cases occurred in the first year of life.In the northern region, most of these cases in the first year of life were observed in infants under the age of six months, and no cases occurred in the eleventh and twelfth months of life (Figure 1).
In the north of Portugal, data on previous vaccination against pertussis was available for the 29 cases in the first year of life reported in the period 2000-2004: none of the 6 infants who were below the recommended age to receive the first dose of DTPw had been vaccinated before the onset of the disease; of the remaining 23, only 7 had been vaccinated.Staff responsible for vaccination are carrying out detailed investigations of the pertussis cases that might have been prevented by vaccination.

Conclusions
No changes were observed in the pattern of presentation of foodborne disease outbreaks linked to consumption of eggs and egg products in 2002 and 2003 in relation to previous years [2].Egg-or egg-product-related outbreaks accounted for 41% of all foodborne disease outbreaks reported to the Outbreak Reporting System in the study period.Salmonella was the causative agent in 85% of outbreaks associated with consumption of eggs, with Enteritidis being the most frequent serotype.The household setting is the predominant place of presentation of reported outbreaks in both the Outbreak Reporting System and the National Reference Laboratory.Outbreaks due to eggs and egg products tend to be more frequent in the months with the highest ambient temperatures, with the principal contributing factors being linked to inadequate food storage temperatures.
The rising trend in the number of outbreaks (both community and household) reported to the Outbreak Reporting System from 1999 to 2003 leads us to believe that, notwithstanding the improvements in the surveillance system in some of the country's Autonomous Regions, no changes have been achieved in the population's habits with regard to basic egg-related salmonellosis prevention measures and, more seriously, that there is continuing non-compliance with the regulations designed to ensure prevention in the food catering sector.With the aim of reducing the incidence of these types of outbreaks, in 2003, the Ministry of Health & Consumer Affairs and the Ministry of Agriculture implemented a salmonella control programme in eggs and egg products [7] which lays down action proposals throughout the food chain.
In contrast to the Outbreak Reporting System, the results obtained by the National Reference Laboratory show a decrease in outbreaks across the study period of over 50% compared to previous years [2] and this substantial decline is again in evidence when the two study years are compared.This could be due to data processing changes implemented since 2002 and could reflect worse compliance in terms of the variables for 'linked to outbreak' and 'food'.Another explanation could be that data from only a small proportion of outbreaks in Spain are collected by the National Reference Laboratory, and a relatively small change in the numbers may result in a large percentage change.
There are currently plans to integrate the data from the National Reference Laboratory and the Outbreak Reporting System, in order to improve knowledge of the risks associated with the appearance of new specific salmonella serotypes.

F I G U R E 1 Foodborne
disease outbreaks associated with eggs and egg products, by place of purchase/consumption, Spain: 2002-2003.

F
Number of outbreaks for which factors are given = 685Source: Outbreak Reporting System, National Epidemiological Surveillance System

F
for which information on control measures adopted is summarised= 685 Source: Outbreak Reporting System.National Epidemiological Surveillance System Over the study period (2002-2003), Spain's National Salmonella and Shigella Reference Laboratory analysed 133 strains corresponding to cases in 37 outbreaks associated with consumption of eggs and egg products (23 outbreaks in 2002 and 14 in 2003).