Submitted to: International Conference on Emerging Zoonoses
Publication Type: Abstract only
Publication Acceptance Date: 6/15/2005
Publication Date: 9/6/2005
Citation: Fridriksdottir, V., Gunnarsson, E., Jonsdottir, G., Astradsdottir, K., Birgisdottir, K., Bjarnadottir, S., Hjartardottir, S., Reiersen, J., Lowman, R., Hiett, K.L., Callicott, K., Stern, N.J. 2005. Campylobacteriosis in chicken in iceland - is vertical transmission of infection taking place?. International Conference on Emerging Zoonoses. Interpretive Summary:
Technical Abstract: Before 1996 relatively few cases of domestically acquired human campylobacteriosis occurred in Iceland. Most infections were acquired abroad. During the years 1998-2000 there was an epidemic in Iceland caused by the consumption of fresh chicken. As a consequence Campylobacter surveillance was included in the regulatory control measures taken in poultry production. In connection with poultry production in Iceland fertilized eggs are imported regularly from grandparent flocks in Sweden, hatching to become parent flocks used in production. The developing breeders are kept in quarantine for 8 weeks and are tested for Campylobacter as a part of quarantine control. There is an additional sampling for Campylobacter at 19 weeks of age after leaving quarantine. In our 2001-2004 project entitled "Sources and Risk Factors for Campylobacter in Poultry and Impact on Human Disease in a Closed System" we began to use the Iceland poultry production system to assess the potentials for vertical transmission. As a part of the project, sample collection has been taking place at various stages of chicken breeding and broiler production, including sampling for regulatory control and surveillance. The purpose of our project was to trace Campylobacter infection in chickens and attempt to identify the most important routes of infection and factors contributing to infection. In this abstract we report on the question of whether "vertical transmission" is contributing to the spread of Campylobacter infection from one generation of chicken to another. Samples for Campylobacter culture were taken from grandparent flock faeces in Sweden in connection with the import of fertilized eggs. Samples were also taken from Icelandic parent flocks held in quarantine 6 weeks after hatching, and again at the age of 19 weeks. Two methods were used for Campylobacter isolation and culture. Initially the traditional NMKL method was used. It was then replaced by the Campy-Cefex method which is less time consuming and in our experience as sensitive as the NMKL method. In a two-year period from June 2001 to June 2003, Campylobacter was isolated from 52% of the grandparent flocks tested. During the same period all samples from 6 weeks old parent flocks tested culture negative. On the other hand when these same parent flocks were tested at the age of 19 weeks, Campylobacter was isolated from 69% of the flocks. Our conclusion is that there was no evidence of vertical transmission of Campylobacter in the flocks tested. Furthermore there was no connection between Campylobacter strains isolated from grandparent flocks and the strains found in parent flocks at 19 weeks of age. Our results show that although eggs imported to Iceland originated from Campylobacter positive birds, there was no sign of vertical transmission of infection from parents to offspring in our sampling material. The fact that Campylobacter was isolated from the offsprings at a later stage can only be explained by environmental sources and not by the spread of infection from the parents.