Outbreak of acute gastroenteritis caused by contamination of drinking water in a factory, the Basque Country.

On 18 September 2013, the Gipuzkoa Epidemiology Unit was notified of an outbreak of acute gastroenteritis (AGE) among employees at a domestic appliance factory. The first signs of the outbreak had emerged at the end of June and at the time of the notification 30 workers were on sick leave for gastroenteritis. Some employees had had more than one episode and the main symptoms were diarrhoea and vomiting. An investigation began to identify the causative agent, assess exposure and determine the route of transmission. Data collected by a questionnaire identified 302 episodes of AGE among 238 people affected between June and September 2013. The source of water consumed was found to be a risk factor associated with the appearance of symptoms both in the crude and the adjusted analysis: odds ratio 1.8 (0.8-4.2) and 6.4 (4.2-9.8), respectively. Microbiological analysis of stool samples and of water confirmed the presence of norovirus and rotavirus. The environmental study detected a connection between an industrial use water system and drinking water at the factory. It was concluded that the outbreak was caused by mixed viral infections, due to contamination of drinking water.

Presence of Giardia cysts and Cryptosporidium oocysts in drinking water supplies in northern Spain.

AIMS: To evaluate the prevalence of Cryptosporidium and Giardia in surface water supplies from the province of Alava, northern Spain, and to investigate possible associations among the presence of these pathogenic protozoa with microbiological, physicochemical and atmospheric parameters. METHODS AND RESULTS: A total of 284 samples of drinking and recreational water supplies were analysed. Cryptosporidium oocysts were found in 63.5% of river samples, 33.3% of reservoirs samples, 15.4% and 22.6% of raw water samples from conventional and small water treatment facilities (respectively), 30.8% of treated water from small treatment facilities, and 26.8% of tap water from municipalities with chlorination treatment only. Giardia cysts were found in 92.3% of river samples, 55.5% of reservoirs samples, 26.9% and 45.2% of raw water samples from conventional and small water treatment facilities (respectively), 19.2% of treated water from small treatment facilities, and 26.8% of tap water from municipalities with chlorination treatment only. The presence of Cryptosporidium and Giardia had significant Pearson's correlation coefficients (P < 0.01) with the turbidity levels of the samples, and a number of significant associations were also found with the count levels for total coliforms and Escherichia coli. The samples were positive for Cryptosporidium significantly (P < 0.05) more frequently during the autumn season than during the spring and winter seasons. No significant differences were found in the seasonal pattern of Giardia. A moderate association (r = 0.52) was found between rainfall and the presence of Cryptosporidium oocysts. CONCLUSIONS: Cryptosporidium and Giardia are consistently found at elevated concentrations in surface waters for human consumption from the province of Alava, northern Spain. SIGNIFICANCE AND IMPACT OF THE STUDY: Water treatments based on rapid filtration process and/or chlorination only are often unsatisfactory to provide safe drinking water, a situation that represents an important public health problem for the affected population because of the risk of waterborne outbreaks.

[Comparison of Yersinia enterocolitica strains isolated from swine and humans in Guipuzcoa]. / Comparación de cepas de Yersinia enterocolitica porcinas y humanas aisladas en Guipúzcoa.

Yersinia enterocolitica biotype 4, serotype 3 is a pathogenic bacteria for men. Its most likely reservoir are pigs. We have compared 48 Y. enterocolitica serotype 0:3 strains isolated from pig's tonsils samples as well as porcine-derived food with 301 Y. enterocolitica serotype 0:3 isolate from human stool's samples. All strains are positive for virulence tests. Yersinia enterocolitica serotype 0:3, biotype 4, phage-type VIII was nearly the only single pathogenic strain isolated from both origins in our county. Human and porcine strains showed a similar percentage of chloramphenicol and cotrimoxazol resistance. This pattern of resistance is not common among Y. enterocolitica strains isolated outside of our geographic area. The nearly identical patterns of human and porcine strains, as well as the high frequency of isolation from pig's tonsils (49.5%) and uncooked meal (12.9%) confirm the hypothesis that pigs are the most likely reservoir for human infections in our county.

[Infectious food poisoning in the Autonomous Basque Community (1984-1986)]. / Toxiinfecciones alimentarias en la Comunidad Autónoma Vasca (1984-1986).

The results of the study of 117 outbreaks of food poisoning in the Basque Autonomous Community during 1984-1986 are reported. In 76% of these outbreaks the causative agent could be isolated. Bacteria of the genus Salmonella accounted for 86.5% of the outbreaks with a known etiology, S. enteritidis being the most commonly found serotype. In 90% of the outbreaks caused by Salmonella, the transmission was by eggs or egg containing products. The features of food poisoning in the Basque Autonomous Community are discussed.