Influenza A H1N1, Chile

Information received on 21/08/2009 from Dr Ternicier Claudio, Jefe División Protección Pecuaria, Servicio Agrícola y Ganadero, Ministerio de Agricultura , Santiago , Chile

Summary

New outbreaks

Outbreak 1 (Foco 1)	Las Palmas, Quilpue, Valparaiso, VALPARAISO
Date of start of the outbreak	23/07/2009
Outbreak status	Resolved (23/10/2009)
Epidemiological unit	Farm
Affected animals	Species Susceptible Cases Deaths Destroyed Slaughtered Birds 29782 24337 0 0 0
Affected Population	The birds are breeding turkeys which presented a drop from 70% to an average of 31%, and a reduction in the quality of the shell. Neither respiratory signs nor increased mortality were observed. Necroscopy of the affected birds showed salpingitis, peritonitis and an interruption of the follicular development. No other lesions were observed. Samples of embryonated eggs collected from the incubation building gave negative results with real-time PCR. Twenty days after the beginning of the event, a recovery in the laying rate was observed.
Outbreak 2 (Foco 2)	Pucalán, Quillota, Nogales, VALPARAISO
Date of start of the outbreak	29/07/2009
Outbreak status	Resolved (23/10/2009)
Epidemiological unit	Farm
Affected animals	Species Susceptible Cases Deaths Destroyed Slaughtered Birds 29772 12248 0 0 0
Affected Population	The birds are breeding turkeys showing an abnormal decrease in the laying rate. Neither respiratory signs nor increased mortality were observed.
Summary of outbreaks	Total outbreaks: 2
Total animals affected	Species Susceptible Cases Deaths Destroyed Slaughtered Birds 59554 36585 0 0 0
Outbreak statistics	Species Apparent morbidity rate Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost* Birds 61.43% 0.00% 0.00% 0.00% * Removed from the susceptible population through death, destruction and/or slaughter

Epidemiology

Source of the outbreak(s) or origin of infection

Unknown or inconclusive

Epidemiological comments

The affected farms are turkey breeding premises belonging to the same company, vertically integrated, where appropriate biosecurity measures are applied. Outbreak no. 1 is composed of 5 breeding premises. The outbreak started in premises no. 1 and through horizontal transmission, it reached 3 other premises. In the outbreak n. 2 of 5 existing sectors are affected. Prior to the appearance of clinical signs, some birds were exposed to people showing respiratory symptoms. The affected premises were systematically monitored through serological testing with negative results until 28 July 2009. Serotyping allowed to exclude the presence of H5 and H7 virus and allowed to confirm detection of A/H1N1 2009 pandemic influenza virus 2009. Samples were sent to the Public Health Institute of Chile (ISP), Ministry of Health. The ISP confirmed the presence of A/H1N1 2009 pandemic influenza virus 2009 using real time PCR. The RT-PCR for seasonal H1 and H3 influenza resulted negative. Samples will be sent to the OIE Reference Laboratory.

Control measures

Measures applied	Quarantine Screening Disinfection of infected premises/establishment(s) Vaccination prohibited No treatment of affected animals
Measures to be applied	No other measures

Diagnostic test results

Laboratory name and type	Public Health Institute (National laboratory)
Tests and results	Species Test Test date Result Birds real-time PCR 20/08/2009 Positive Birds virus sequencing 21/08/2009 Pending
Laboratory name and type	Quarantine Station and Lo Aguirre Laboratory (National laboratory)
Tests and results	Species Test Test date Result Birds agar-gel immunodiffusion (AGID) 15/08/2009 Positive Birds antibody detection ELISA 14/08/2009 Positive Birds haemagglutination inhibition test (HIT) 19/08/2009 Positive Birds neuraminidase inhibition assay 19/08/2009 Positive

Future Reporting

The event is continuing. Weekly follow-up reports will be submitted.

Map of outbreak locations

Location of current outbreaks

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