First outbreak
On 21 January 2007, an increase in deaths among geese at a farm near Lapistó village (Csongrád county in southern Hungary) was reported to the Hungarian veterinary authorities. The breeding flock consisted of 3355 birds. Two birds died on 19 January, eight on 20 January, and 18 on 21 January. During an investigation at the farm on 21 January, more than 30 birds with neurological symptoms were discovered. On 22 January, 29 more deaths in this flock were registered in the morning and further 33 during the day. [1,2]

The following measures were taken to contain the outbreak:

• On 22 January, five dead geese were sent to the national reference laboratory for further analysis.
• On 23 January, all 3265 birds on the farm were culled (90 died in the outbreak) and the farm was disinfected.
• A 3-kilometre protection zone and 10-kilometre surveillance zone were set up around the affected farm. There are no settlements within one kilometre distance from the farm, but there are 57 households with backyard poultry (1743 birds) within the 3-kilometre zone, and further 1253 households with backyard poultry (29 590 birds) and 8 large farms with around 47 000 birds within the 10-kilometre zone.
• All domestic birds within the two zones were examined.
• The European Commission was informed of the suspected outbreak of avian influenza.

On 24 January, the national reference laboratory announced that the samples collected from dead geese at the Lapistó farm contained the highly pathogenic A/H5N1 virus. These findings were confirmed on 30 January by the European Union reference laboratory in Weybridge, United Kingdom.

On 23-24 January, regional public health authorities assessed the possible risk of exposure of poultry workers [3]. One person who had worked closely with the birds but had not worn protective overalls was offered and accepted chemoprophylaxis immediately. Further 11 people who had been involved in culling the birds received medication after the virus was identified, because although they had been given all the necessary protective equipment (a Tyvec overall with headwear, rubber boots, heavy duty rubber work gloves, and a respiratory protective device with FFP3 filter), they had not observed all the recommended hygiene rules and the possibility that they had been exposed to the virus could not be excluded. There have been no reports of illness in people who were potentially exposed.

Second outbreak
On 25 January, veterinary authorities were notified of another possible outbreak of avian influenza at a goose farm in Derekegyháza, 9 km from the site of the first outbreak. The flock consisted of 6000 four week-old and 3 386 eight week-old geese. On 23 January, 6 geese died, the following day the number of deaths was 24, on 25 January – 21, on 26 January - 289. By 27 January altogether 2 596 geese died in the outbreak, the remaining 6790 geese were culled. In addition, in order to control the outbreak, further 367 birds which were found in 4 households within 1-kilometre distance from the outbreak were also culled.

On 30 January the Hungarian national reference laboratory confirmed that the outbreak at Derekegyháza farm was also caused by the highly pathogenic A/H5N1 virus.

In consequence of the second outbreak, the “A” zone was modified to include the 3- and 10-kilometre zones around both outbreak sites. Since 29 January clinical examination of poultry found within the “A” zone and laboratory testing of samples has been carried on. In one sample taken from a goose the presence of A/H5 antibodies was asserted. Although none of the 4500 geese kept at the farm where this sample was taken from displayed any symptoms, the entire flock was culled on 7 February.

Three poultry workers who were employed at the farm in Derekegyháza were offered and accepted chemoprophylaxis. No medication was given to the 21 people brought in to assist in the culling of birds, because they had used protective equipment correctly and it was highly likely that they had not been exposed to infection. They are, however, being monitored and there are no reports of illness so far. There will also be a serological follow-up of all people who were potentially exposed during these outbreaks. [3]

Acknowledgements:
Dr Ágnes Csohán, Head of Department of Epidemiology, National Centre for Epidemiology, Budapest, Hungary.