Avian Influenza (AI) Outbreak Avian Influenza (AI) Outbreak among - PowerPoint PPT Presentation

Avian Influenza (AI) Outbreak Avian Influenza (AI) Outbreak among Poultry in a High Risk Area, among Poultry in a High Risk Area, Thailand, June- -December 2005 December 2005 Thailand, June Karoon Chanachai Chanachai , DVM Karoon , DVM Field Epidemiology Training Program - Field Epidemiology Training Program - Thailand Thailand Tippawan Prakmawongsanon , Tippawan Prakmawongsanon , DVM, DVM, MSc MSc Suphanburi Provincial Livestock Office Suphanburi Provincial Livestock Office Chuleeporn Jiraphongsa Jiraphongsa , MD, PhD Chuleeporn , MD, PhD Field Epidemiology Training Program - - Thailand Thailand Field Epidemiology Training Program

Background Background Jan 2004: the first avian influenza-H5N1 (AI) outbreak in poultry officially reported in Thailand. 2004-2005: the AI persisted in same areas In Thailand, native chickens, broilers, layers, bantams, guinea fowl, quail, ducks, geese, sparrow, pigeons and Asian open- billed stork were found AI positive

Geographical Location of AI Confirmed Flocks Jul 2004-Dec 2005 Most affected areas were in central and lower northern parts of Thailand

100 150 200 250 300 Number of confirmed flock 50 0 3/7 - 9/7 10/7 - 16/7 (n = 1,724; data source Department of Livestock (n = 1,724; Laboratory Confirmation of AI in Poultry Flocks, Laboratory Confirmation of AI in Poultry Flocks, 17/7 - 23/7 24/7 - 30/7 31/7 - 6/8 7/8 - 13/8 14/8 - 20/8 21/8 - 27/8 28/8 - 3/9 4/9 - 10/9 2004 11/9 - 17/9 18/9 - 24/9 2004 25/9 - 1/10 active surveillance campaign 2/10 - 8/10 9/10 - 15/10 16/10 - 22/10 Thailand Jul 2004 – Thailand Jul 2004 23/10 - 29/10 30/10 - 5/11 6/11 - 12/11 data source Department of Livestock Development ,Thailand 13/11 - 19/11 20/11 - 26/11 27/11 - 3/12 4/12 - 10/12 11/12 - 17/12 18/12 - 24/12 25/12 - 31/12 1/1 - 7/1 8/1 - 14/1 15/1 - 21/1 22/1 - 28/1 29/1 - 4/2 5/2 - 11/2 active surveillance campaign 12/2 - 18/2 19/2 - 25/2 Date 26/2 - 4/3 5/3 - 11/3 12/3 - 18/3 19/3 - 25/3 26/3 - 1/4 2/4 - 8/4 9/4 - 15/4 16/4 - 22/4 – Dec 2005 23/4 - 29/4 30/4 - 6/5 7/5 - 13/5 Dec 2005 14/5 - 20/5 21/5 - 27/5 28/5 - 3/6 4/6 - 10/6 11/6 - 17/6 2005 18/6 - 24/6 Development ,Thailand ) 2005 25/6 - 1/7 2/7 - 8/7 active surveillance campaign 9/7 - 15/7 16/7 - 22/7 23/7 - 29/7 30/7 - 5/8 6/8 - 12/8 13/8 - 19/8 20/8 - 26/8 27/8 - 2/9 3/9 - 9/9 10/9 - 16/9 17/9 - 23/9 24/9 - 30/9 1/10 - 7/10 8/10 - 14/10 15/10 - 21/10 22/10 - 28/10 29/10 - 4/11 5/11 - 10/11 active surveillance campaign ) 11/11 - 17/11 18/11 - 24/11 25/11 - 1/12 2/12 - 8/12 9/12 - 15/12 16/12 - 22/12 23/12 - 29/12

Background (2) Background (2) 2005: 848 suspect and 188 AI confirmed flocks First epizootic occurred Jan to Apr, No flock reported positive for 2 months Epizootic recurrence in June 2005 Jun – Dec 05: 70 confirmed flocks Suphanburi 25 flocks Kampangphet 23 flocks Kanchanaburi 6 flocks

Objectives Objectives To characterize the AI poultry outbreak in Suphanburi province from Jun to Dec 2005 To identify the possible risk factors of the outbreak To give recommendations for outbreak investigation, control and prevention in the future

Methodology (1) Methodology (1) Descriptive study Reviewed the positive cases reported in Suphanburi at Department of Livestock Development Reviewed active case finding in poultry at Suphanburi Provincial Livestock Office Interviewed poultry owners of all confirmed flocks in the province about demographic data clinical symptoms onset date number of dead poultry in the first three day other characteristics of the outbreak

Case Definition of AI Infected Flocks Case Definition of AI Infected Flocks Poultry flocks in Suphanburi province* Suspect flocks: Poultry flocks with > 10% die off within one day from unknown cause and have at least one of following clinical signs: sudden death, respiratory system illness, neurological system illness or diarrhea Confirmed flocks: Flocks with laboratory confirmation of H5 by hemagglutination test performed by National Institute of Animal Health * Case definition of the Department of Livestock Development during Jun – Dec 2005

Methodology (3) Methodology (3) Matched case control study Conducted in Nov 2005 to identify potential risk factors among confirmed flocks 1 case : 2 control Cases were confirmed flocks from descriptive study Control flocks were randomly selected from houses within 20 houses around case flocks; control flocks had no abnormal death of poultry Jun – Nov 2005 Analysis was performed using Epi-Info version 3.3

Methodology (4) Methodology (4) Environmental study Reviewed data of poultry population and natural bird survey from provincial natural resources authority Analyzed the association of poultry population and occurrence of suspect and confirmed AI at the village level using correlation analysis

Results Results

AI Confirmed Flocks in Suphanburi Suphanburi AI Confirmed Flocks in Province, Jun- -Dec 2005 Dec 2005 Province, Jun There were 54 suspect flocks and 25 confirmed flocks. Confirmed flocks were found in 6 of the province’s 10 districts. The flocks were located in 22 sub-districts and 24 villages. * There are 10 districts, 110 sub-districts and 998 villages in Suphanburi province

Spatial Distribution of Suspect and AI Confirmed Flocks Jun- Dec 2005

Number of flocks 10 12 Onset Date of Suspect and Confirmed Flocks Onset Date of Suspect and Confirmed Flocks 0 2 4 6 8 1 6 /6 -2 2 /6 2 3 /6 - 2 9 /6 3 0 /6 - 6 /7 7 /7 - 1 3 /7 1 4 /7 - 2 0 /7 2 1 /7 - 2 7 /7 Jun- Jun 2 8 /7 - 3 /8 4 /8 - 1 0 /8 -Dec 2005 (n= 79) Dec 2005 (n= 79) 1 1 /8 -1 7 /8 1 8 /8 -2 4 /8 2 5 /8 -3 1 /8 1 /9 -7 /9 Date 8 /9 -1 4 /9 1 5 /9 -2 1 /9 2 2 /9 - 2 8 /9 2 9 /9 -5 /1 0 6 /1 0 -1 2 /1 0 1 3 /1 0 -1 9 /1 0 2 0 /1 0 - 2 6 /1 0 2 7 /1 0 - 2 /1 1 3 /1 1 -9 /1 1 1 0 /1 1 -1 6 /1 1 Analytic study 1 7 /1 1 -2 3 /1 1 2 4 /1 1 -3 0 /1 1 Confirmed Suspect 1 /1 2 -7 /1 2

Flock Size by Type of AI Confirmed Flock Size by Type of AI Confirmed Flocks Flocks Median Flock Size Proportion Type of flock Number (% ) (range) Backyard Chickens 16 100 (10-200) 64 Free-grazing ducks 2 3,450 (2,400-4,500) 8 Layers 2 1,010 (19-2,000) 8 Broilers 2 9,400 (8,000-10,800) 8 Quail 3 96,000 12 (50,000-122,000) Total 25 - 100

Cumulative Mortality Rate among Backyard Chicken and Cumulative Mortality Rate among Backyard Chicken and Free- -grazing Duck Flocks with Confirmed AI (n= 18) grazing Duck Flocks with Confirmed AI (n= 18) Free 35 30 25 Percent 19 (13,27) 20 15 10 (6,29) 10 4 (2,7) 5 0 day1 day2 day3 Day after onset a (b, c) = median (1 st , 3 rd quartile)

Cumulative Mortality Rate among Broiler, Layer and Quail Cumulative Mortality Rate among Broiler, Layer and Quail Flocks with Confirmed AI (n= 7) Flocks with Confirmed AI (n= 7) 3.50 3.00 2.50 Percent 2.00 1.50 1.00 0.46 0.31 (0.15-0.81) (0.07-2.97) 0.50 0.10 (0.03-0.31) 0.00 day1 day2 day3 Day after onset a (b, c) = median (1 st , 3 rd quartile)

Timeliness of Important Events Timeliness of Important Events among the Confirmed Flocks among the Confirmed Flocks Abnormal death of poultry observed by owner 2 days (0 - 9 days) Owner informed involved person 2 days (0-18 days) Culling poultry flock

Results of Results of Match Case Control Study Match Case Control Study

Univariate Matched Analysis Results Matched Analysis Results Univariate Case Control Adjusted odds ratio Risk factors (95% CI ) Non- Non- Exp Exp exp exp 15 8 17 32 4.25 (1.22-14.84) Abnormal die off of neighborhood poultry 3 22 0 50 Infinite dead poultry introduced to farm site (by dog) 7 18 10 40 1.80 (0.48-6.75) Shared feeding area with other domestic poultry

Univariate Matched Analysis Results (2) Matched Analysis Results (2) Univariate Match odd ratio Case Control (95% CI ) Risk factors Non- Non- Exp Exp exp exp 2 23 7 43 0.67 (0.13-3.30) Contact or proximity with free-grazing ducks 15 10 14 36 6.33 (1.64-24.47) Contact or proximity with water fowl feeding area 9 16 3 47 8.50 (1.79-30.31) Observed illness or death among natural birds

Univariate Matched Analysis Results (2) Matched Analysis Results (2) Univariate Match Case Control Risk factors odd ratio Non- Non- Exp Exp (95% CI ) exp exp 3 22 12 38 0.45 (0.12-1.72) Cock fighting 6 19 8 42 2.00 (0.71-5.66) Introduction of possible fomites (vehicle, poultry)

Multivariate Matched Analysis Results Multivariate Matched Analysis Results Case Control Adjusted odd ratio Risk factors (95% CI ) Non- Non- Exp Exp exp exp 15 10 14 36 10.68 (1.29-88.38) Contact or proximity with water fowl feeding area 3 22 0 50 infinite dead poultry introduced to farm site (by dog) 15 8 17 32 Abnormal die offs of 1.87 (0.42-8.24) neighborhood poultry 9 16 3 47 Observed sick or dead 2.42 (0.39-14.97) natural birds

I nverse Distance Weighted of Free-grazing Ducks and Point Location of AI outbreaks • Total 736 free- grazing duck flocks and 1,693,121 free- grazing ducks • P-value = 0.70 (Correlation analysis)