Volume 11, Number 11—November 2005
Synopsis
Highly Pathogenic Avian Influenza H5N1, Thailand, 2004
Table 1
Poultry population categorized by geographic region in Thailand in 2003
Poultry population | North | Central | East | South | Northeast | Total | RR (95% CI)* |
---|---|---|---|---|---|---|---|
Backyard chickens | |||||||
Birds | 18,067,529 | 9,312,042 | 3,880,535 | 6,280,375 | 25,551,093 | 63,091,574 | |
Flocks | 543,793 | 143,829 | 81,804 | 241,886 | 1,125,352 | 2,136,664 | |
Infected flocks | 491 | 296 | 107 | 31 | 94 | 1,019 | |
Incidence, % | 0.0903 | 0.2058 | 0.1308 | 0.0128 | 0.0084 | 0.0477 | 1.0 |
Layers | |||||||
Birds | 2,288,485 | 7,682,667 | 8,304,081 | 2,113,035 | 3,924,255 | 24,312,523 | |
Flocks | 4,209 | 6,396 | 3,941 | 7,666 | 14,264 | 36,476 | |
Infected flocks | 29 | 42 | 14 | 1 | 6 | 92 | |
Incidence, % | 0.6890 | 0.6567 | 0.3552 | 0.0130 | 0.0421 | 0.2522 | 5.3 (4.4–6.4) |
Broilers | |||||||
Birds | 12,442,797 | 70,414,281 | 53,681,571 | 6,565,161 | 22,210,976 | 165,314,786 | |
Flocks | 4,588 | 6,242 | 6,507 | 6,166 | 22,274 | 45,777 | |
Infected flocks | 44 | 54 | 8 | 3 | 2 | 111 | |
Incidence, % |
0.9590 |
0.8651 |
0.1229 |
0.0487 |
0.0090 |
0.2425 |
5.1 (4.3–6.1) |
Ducks | |||||||
Birds | 2,567,666 | 8,026,701 | 6,110,934 | 1,777,466 | 5,317,325 | 23,800,092 | |
Flocks | 58,606 | 33,607 | 17,917 | 95,216 | 478,483 | 683,829 | |
Infected flocks | 85 | 355 | 29 | 9 | 13 | 491 | |
Incidence, % | 0.1450 | 1.0563 | 0.1619 | 0.0095 | 0.0027 | 0.0718 | 1.5 (1.3–1.7) |
Quails | |||||||
Birds | 199,357 | 2,920,216 | 189,342 | 302,291 | 81,597 | 3,692,803 | |
Flocks | 147 | 324 | 114 | 1,797 | 211 | 2,593 | |
Infected flocks | 12 | 26 | – | 1 | 1 | 40 | |
Incidence, % | 8.1633 | 8.0247 | 0 | 0.0556 | 0.4739 | 1.5426 | 32.4 (26.5–39.5) |
Geese | |||||||
Birds | 8,098 | 154,723 | 101,465 | 9,980 | 34,401 | 308,667 | |
Flocks | 1,650 | 1,870 | 923 | 2,596 | 7,646 | 14,685 | |
Infected flocks | 4 | 8 | 3 | – | 1 | 16 | |
Incidence, % | 0.2424 | 0.4278 | 0.3250 | 0 | 0.0131 | 0.1090 | 2.3 (1.4–3.7) |
Other | |||||||
Infected flocks |
10 |
14 |
6 |
– |
10 |
40 |
|
Total | |||||||
Birds | 35,573,932 | 98,510,630 | 72,267,928 | 17,048,308 | 57,119,647 | 280,520,445 | |
Flocks† | 612,993 | 192,268 | 111,206 | 355,327 | 1,648,230 | 2,920,024 | |
Infected flocks‡ | 665 | 781 | 161 | 45 | 117 | 1,769 | |
Incidence, % | 0.1085 | 0.4062 | 0.1448 | 0.0127 | 0.0071 | 0.0606 | |
RR (95% CI) | 1.0 | 3.7 (3.4–4.1) | 1.3 (1.1–1.6) | 0.1 (0.01–0.15) | 0.05 (0.06–0.08) |
*Relationship between cumulative incidence and relative risk (RR) of influenza H5N1 epidemic. Cumulative incidence of infected flocks of backyard chickens and the Central Region were assigned an RR of 1.0.
†Included only the number of flocks of backyard chickens, layers, broilers, ducks, quails, and geese. Some flocks are mixed types of poultry on site.
‡Included only the number of infected flocks of backyard chickens, layers, broilers, ducks, quails, and geese.