Latvian health officials have completed their investigation into an outbreak and general rise in E. coli which led to almost 80 sick people.

The Center for Disease Prevention and Control (SPKC) said the epidemiological investigation revealed 77 infections caused by E. coli from March 19 to April 16.

E. coli sequencing results were received for 57 cases. Results showed the outbreak was caused by two E. coli serotypes – O26:H11 and O103:H2.

Of 46 infected people, 41 were children and five were adult employees of educational institutions involved in the incident. The other 11 people were sporadic E. coli cases and not part of the outbreak.

More than a dozen HUS cases
Clinical symptoms were observed in 29 cases, 14 children developed Hemolytic Uremic Syndrome (HUS), and 22 people were treated in hospitals. HUS is a rare but severe complication associated with E. coli infections that causes kidney failure and sometimes death.

The 46 infections in the outbreak were detected in 21 educational institutions. A dozen more cases of E. coli in children were found at these sites. Despite no sequencing, SPKC said they can be considered as being related to the outbreak.

SPKC and the Latvian Food and Veterinary Service (PVD) analyzed connections between these settings and caterers and food suppliers. Results pointed to a dairy company called PKS Straupe as the only firm that directly or indirectly supplied products to the institutions.

Genetically related E. coli O26:H11 was also detected in one child who did not attend an educational establishment, but a survey with parents revealed the youngster had consumed products made by PKS Straupe.

Testing at the company
Sequencing of seven samples from PKS Straupe employees was performed. This revealed O75:H38 in four cases, while O177:H11, O84:H2, and O5:H4 were all found once. The outbreak-causing E. coli serotypes were not detected in PKS Straupe staff.

E. coli O75:H38 was also detected in four other children’s educational settings in Sigulda, āda?i and Cēsis. This included two adults and four children. Sequencing results indicated an epidemiological link between all 10 cases, which formed one cluster. All four institutions were supplied with milk products by PKS Straupe.

E. coli was detected in three food products at the Institute of Food Safety, Animal Health and Environment (BIOR). Results of laboratory screening indicated the presence of E. coli in raw milk from three farms.

In a statement, PKS Straupe said it had not yet received official findings from SPKC but it has already taken enhanced safety measures in the facility and the production process under the supervision of the PVD. Operations only resumed after the PVD issued a permit.

Imants Balodis, chairman of the board of PKS Straupe, said: “Our priority is the safety of the public and our customers, so we will cooperate with SPKC and follow their recommendations. I also confirm that the company works taking into account the highest food safety criteria. I definitely want to meet with SPKC representatives in person to discuss the laboratory results in detail, which still makes me ask many questions. I sincerely apologize to parents and children if our products have caused any unpleasant moments.”