Prevalence of salmonella spp in poultry in vietnam

Prevalence of Salmonella spp. in Poultry
in Vietnam
TRAN T. HANH,a NGUYEN T. THANH,a HOANG Q. THOA,b LE T. THI,c
LAM M. THUAN,d AND NGUYEN T.H. LYe
a National

Institute of Veterinary Research, Hanoi, Vietnam

b Hanoi

Regional Animal Health Center, Hanoi, Vietnam
c Sub of National Institute of Veterinary Research, Khanhhoa, Vietnam
d Thu

Duc Agricultural and Forest University, Hochiminh, Vietnam

e National

Center for Veterinary Hygiene Inspection N02, Hanoi, Vietnam

ABSTRACT: The prevalence of Salmonella spp. in chickens and ducks
from North, Central, and South Vietnam was followed over a 4 year
period. Several different analyses were employed and the current prevalence was shown to be less than in previous studies.
KEYWORDS: Salmonella; prevalence; poultry

INTRODUCTION
The aim of this article is to present the prevalence of Salmonella spp. in
poultry in Vietnam. Investigations of bacterial food poisoning outbreaks in
Alexandria, Egypt in 1999 detected Salmonella spp. in 16 outbreaks with 43
cases. S. enteritidis (5 out of 16 outbreaks with 13 cases) was the most prevalent
serovar. Japan registered 1217 outbreaks of all types of food poisoning in 1996,

involving 46,327 cases. In Vietnam from 1997 to 2000 there were 1364 food
poisoning outbreaks with 24,541 cases, 207 died.1 In Ho Chi Minh city in
1994, 370 cases of food poisoning following consumption of contaminated
soup were identified as Salmonellosis. Another food-borne poisoning of 300
cases caused by S. enteritidis in Thai Binh in North Vietnam was reported.
There was no information about the reservoir and routes for food poisoning
agents.

MATERIALS AND METHODS
The study was carried out to determine the prevalence of Salmonella spp.
in chicken and ducks in the North, Central, and South Vietnam in a period of
Address for correspondence: Tran Thi Hanh, National Institute of Veterinary Research, Hanoi,
Vietnam.
e-mail:
Ann. N.Y. Acad. Sci. 1081: 266–268 (2006).
doi: 10.1196/annals.1373.034

C

2006 New York Academy of Sciences.
266


HANH et al.: SALMONELLA SPP. IN POULTRY

267

4 years from 2001 to 2004. In total 6557 samples were analyzed during this
period. Samples were randomly collected in various breeding farms as fecal
samples, rectal swabs, collected floor feces, inner organs (intestine, cecum,

liver) from dead chicken of any age, and dead embryos from unhatched eggs.
Bacteriological analyses were developed as follows2,3 : (a) pre-enrichment
on buffered peptone water (BPW); (b) selective enrichment using Rapport
Vassiliadis (RV); (c) plating on XLD agar and MacConkey agar; and (d) biochemical confirmation using Kligler, API 20, or micro-ID3; 5-serotyping by
poly OH.

RESULTS
In North Vietnam, Salmonella spp. were isolated in chicken samples from
113/2824 (4%) of the feces, from 28/907 (3.09%) of the organ samples, and
from 26/412 (6.31%) of the dead embryos. In ducks, Salmonella positive samples were found in 5.57% (53/950) of the feces, in 9.52% (12/126) of the
organs, and in 10.12% (16/158) of the dead embryos. In Central Vietnam,
6 out of 100 (6%) duck organ samples were found positive with Salmonella
spp. Feces and organ samples were not taken. In chickens, none of the samples
were positive out of 70 fecal, 50 organ, and 80 dead embryos samples. In South
Vietnam, fecal samples were not taken. In chicken, 22/326 (6.7%) of organ
samples, 6/200 (3%) of dead embryos were found positive for Salmonella spp.,
whereas in duck, 6/42 (14.3%) of the organ samples and 10/312 (3.2%) of the
dead embryos were positive. These results are summarized in TABLE 1.

DISCUSSION AND CONCLUSION
In previous studies, such as in 1998 on 502 samples of feces and eggs
collected from 7 duck farms in Ho Chi Minh city and surrounding areas, Tran
Xuan Hanh4 reported a Salmonella spp. prevalence of 8.8% on duck hens,
24.7% on duckling, and 31.7% on dead embryos. In 1999, Tran Thi Hanh5
found 30.91% Salmonella spp. in a week old infected chicken.
TABLE 1.

Areas
North
Central

South
Total

Prevalence of Salmonella spp. in three areas of Vietnam

Breeding
farms
Chicken
Duck
Chicken
Duck
Chicken
Duck

Number of
samples (n)

Number of
positive samples

Percentage (%)

4,143
1,234
200
100
526
354
6,557

167
81
0
6
28
16
298

4.00
6.56
0.00
6.00
5.32
4.51
4.60


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ANNALS NEW YORK ACADEMY OF SCIENCES

In conclusion, the Salmonella spp. prevalence found in our recent investigation is lower than the above mentioned authors.

REFERENCES
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lebend impfstoffen bei lebensmittelliefernden Tieren. Berl. Munch. Tieraurzl.
Wschr. 114: 428–432.

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