[Exposure to avian influenza virus and the infection status of virus among people breeding or butchering ducks in the suburb of Beijing].
OBJECTIVE
To understand the exposure and the infection status of virus among people engaging in breeding or butchering ducks in the suburb of Beijing.


METHODS
People from six districts (Daxing, Fangshan, Huairou, Miyun, Shunyi, Tongzhou) who engaged in breeding or butchering ducks were studied and the status of infecting avian influenza virus was obtained by testing antibody level in serum. Information on demographic characteristics, status of regular exposure and exposure to sick or dead poultry were collected through a self-designed questionnaire.


RESULTS
1741 people were involved in this study in which 313 (18.0%) were workers in duck-breeding enterprise, 562 (32.3%) were workers in duck slaughterhouse, 261 (15.0%) farmers were in individual small-scale duck farms, 605 (34.7%) were farmers raising duck in backyard. Among farmers raising duck in backyard, the percentage of people whose ducks ever contacted with wild birds was higher than the other three groups (66.8%) (P<0.05). Among farmers who bred their ducks in the backyard (35.2%) and those abattoir workers (31.3%), the percentage of people who had contacted ducks but not been vaccinated with avian influenza vaccine was higher than the other two groups (P<0.05). Regarding the status on cleaning and disinfection among the studied farmers who had bred their ducks in the backyard, the percentage of people who had closer contact with ducks would clean the settings more than 4 times per month (8.8%) and disinfected those places more than 12 times per year (27.3%) but still lower than the other three groups (P<0.05). Among those farmers who bred ducks in the backyard, the percentage of people who had ever touched duck with their hands was high (34.4%) (P<0.05). Regarding exposure to sick or dead poultry, higher proportion was found among those who had ever closely contacted sick or dead poultry commercial duck raisers (36.1%) and individuals who raise large amount of ducks (36.0%). 70.8% of the individual duck raisers had never taken any protective measures when closely contacting the sick or dead poultry. Among 1741 samples, 0 were positive to avian influenza virus H5 and H7 subtypes. 12 were positive to H9 subtype (positive rate was 0.7%), in which 10 were farmers raising ducks in backyard (the positive rate of 1.7%). Differences between H9 subtype antibody positive rates difference in 4 population groups were statistically significant (χ2=13.699, P<0.05).


CONCLUSIONS
Farmers who bred their ducks in the backyard had greater risk of contracting the avian influenza. Individual duckers who raise ducks in large scale and the farmers who bred their ducks in the backyard were in lack of protective measures when contacting the sick or dead poultry. Our findings suggested that some intervention measures should be taken to reduce the risk of avian influenza infection.
School of Public Health and Family Medicine, Capital Medical University, Beijing 100069, China.
Chun-na
CN
Ma
Peng
P
Yang
Yi
Y
Zhang
Hai-yue
HY
Li
Li
L
Zhang
Li-li
LL
Li
Chao
C
Li
Yu-song
YS
Yang
He
H
Chen
Song-jian
SJ
Zhang
Xiu-jun
XJ
Liu
Quan-yi
QY
Wang
D000293:Adolescent; D000328:Adult; D000822:Animal Husbandry; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002681:China / Q000453:epidemiology; D004372:Ducks; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000145:classification; D007251:Influenza, Human / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult
D000914:Antibodies, Viral