See also: 9 May 2003, 25 April 2003, 18 April 2003, 7 February 2003, 24 January 2003, 17 January 2003, 10 January 2003, 29 November 2002, 22 November 2002, 8 November 2002, 1 November 2002, 25 October 2002, 18 October 2002, 4 October 2002

Information received on 30 December 2002 from Dr Peter Fernandez, Associate Administrator, Animal and Plant Health Inspection Service, United States Department of Agriculture (USDA), Washington, DC:

End of previous report period: 22 November 2002 (see Disease Information, 15 [48], 248, dated 29 November 2002).

End of this report period: 27 December 2002.

Outbreaks:

Location	No. of outbreaks
Los Angeles, Riverside and San Bernardino Counties, State of California	1*

* 247 known positive backyard premises and 1 commercial facility.

Details of the outbreak in a commercial poultry operation: on 18 December 2002, birds from a commercial egg-laying operation located within the quarantined area (Riverside county) were showing clinical signs of Newcastle disease. This facility is a two-flock egg-layer operation with approximately 105,000 birds amongst the two flocks. On 20 December, samples were sent to National Veterinary Services Laboratories (NVSL), Ames, Iowa, for testing. One flock was presumptive positive by preliminary laboratory findings and the other flock was considered a dangerous contact. On 27 December, Newcastle disease was confirmed by NVSL.

Epidemiology:

A. Source of agent / origin of infection: molecular epidemiology and phylogenetic analysis shows the southern California isolate to be very closely related to the exotic Newcastle disease virus isolated in northern Mexico during their 2000 outbreak.

B. Mode of spread: the commercial facility is located within the quarantined area.

C. Other epidemiological details: since confirmation of the disease in the United States of America on 1 October 2002, the incident continues to be contained within a 30-mile (approx. 48-km) radius in Los Angeles County and along the Los Angeles / Riverside / San Bernardino County border. No commercial poultry are affected outside the three-county quarantined area at this time.

Control measures: same as previous report.

- Depopulation of the affected commercial premises: approximately half of the birds were killed on 22 December; the remaining birds were killed on 24 December.

- Depopulation of affected/exposed backyard flocks: to date, 247 positive backyard premises have been depopulated, as well as 353 premises with direct contact with positive birds.

Source: OFFICE INTERNATIONAL DES EPIZOOTIES - 3rd January 2003