Transcript Quality of water spinach in Phnom Penh and Hanoi

Microbiological quality of water spinach
grown in the Boeng Cheung Ek lake in
Phnom Penh and in peri-urban aquatic
systems in Hanoi
Vuong Tuan Anh1, Lise Tønner Klank2, Phung Dac Cam1,
Anders Dalsgaard2.
1Division
of Enteric Infection Diseases, National Institute of Hygiene and
Epidemiology, Vietnam; 2Department of Pathobiology, Royal Veterinary
and Agricultural University, Denmark
Study objectives
1.
2.
To determine the numbers of
thermotolerant
coliforms,
helminth eggs and protozoan
parasites in water spinach
grown in Boeng Cheung Ek
(BCE) lake, Phnom Penh and at
two peri-urban communes in
Hanoi,
including
samples
harvested with and without
wastewater (ww) exposure
To assess the association
between microbiological water
quality and of water spinach
Sites and methodology


Sampling sites and schedule

Phnom Penh: 2 inlets, 1 outlet of BCE lake and the control
site (a small pond); all sites sampled four times; with and
without ww exposure of plants

Hanoi: one ww-irrigated site, one rainwater-irrigated site, 6
fields at each site sampled during wet and dry seasons
(duplicate samples)
Number of sample collected: 68 plant samples in Phnom
Penh; 216 plant samples in Hanoi
Sites and methodology

Parameters: thermotolerant coliforms, E. coli, helminth
eggs (Ascaris lumbricoides, Trichuris trichiura, hookworm)
and protozoa (Giardia intestinales, Cryptosporidium
parvum and Cyclospora spp.)

Sample analysis: Cambodian Pasteur Institute and NIHE

Laboratory methods: MPN for thermotolerant coliforms
and helminth egg enumeration according to WHO manual
1996, Immuno-flourescent microscopy to detect protozoan
parasites
Phnom Penh results: Numbers of
thermotolerant coliforms and E.
coli in water spinach
10
7
6
8
5
4
6
3
2
39
2
N=
18
18
18
6
JICA
Trabek
Steung Chrov
control
location of sampling
E.coli log
4
1
0
N=
4
8
1
2
JICA
Trabek
Steung Chrov
control
location of sampling
Phnom Penh: protozoan parasites in
water spinach (total 68 samples)
Number of positive samples
12
10
8
6
4
2
0
JICA
Trabek
Cyclospora
Steung Chrov
Cryptosporidium
Giardia
Control
Phnom Penh: helminth eggs
qualitative analysis
Sampling Hook- Ascaris Trichuris
location
worm
spp.
spp.
JICA1
0/12
0/12
0/12
Trabek1
0/12
1/12
0/12
Steung
Chrov2
1/12
2/12
0/12
Control
0/8
1/8
0/8
1
inlet; 2
outlet
Phnom Penh: nos of thermotolerant
coliforms in water spinach exposed versus
non-exposed to ww during harvest
10
14
13
8
21
6
4
un-exposure of w ater
exposure of w ater
2
N=
9
JICA
9
9
9
Trabek
location of sampling
9
9
Steung Chrov
3
3
Control
Correlation of microbiological quality of
water and water spinach
10
8
6
81
77
117
73
90
94
86
4
w ater spinach
39
2
w ater
N=
25
18
25
control (w ater)
18
25
Trabek
JICA
location of sampling
18
25
6
Control (veg)
Steung Chrov
1,00E+05
Hanoi results: Thermotolerant
coliforms in water spinach (log MPN/g)
1,00E+04
1,00E+03
1,00E+02
1,00E+01
1,00E+00
WW-wet season
A=harvested by NIHE
BL=after storage overnight, before leaving for market
WW-dry season
Non-WW-wet season
B=harvested by farmer, no postharvest washing
D=upon arrival to market
Non-WW-dry season
C=harvested by farmer, plus postharvest washing
Hanoi results: Seasonal occurrence of protozoan
parasites in ww-irrigated and rainwater-irrigated water
spinach (%) (total of 216 samples) in peri-urban
Hanoi
50
45.8
45
Cyclospora
Giardia
40
Cryptosporidium
35
33.3
%
30
25
18.8
20
15
11.9
11.9
10.0
10
6.3
6.7
6.3
6.7
5
3.3
2.1
0
WW-April-May
WW-Nov-Dec
Non-WW-April-May
Non-WW-Nov-Dec
Hanoi results: helminth egg
qualitative analysis
Sampling
location
WW-irrigated site –
Wet season (n=48)
Hookworm
Ascaris
spp.
Trichuris
spp.
0/48
1/48
0/48
WW-irrigated site –
Dry season (n=48)
0/48
2/48
0/48
Non-WW-irrigated site
– Wet season (n=60)
0/60
0/60
0/60
Non-WW-irrigated site
– Wet season (n=60)
0/60
0/60
0/60
Phnom Penh study – Conclusions
• Thermotolerant coliforms
– Relatively higher levels (105-106 /g) on water
spinach
• Protozoan parasites
– Giardia is most prevalent, particularly in plant
samples collected at inlets
• Helminth eggs
– Very low levels detected at all sampling sites
Hanoi study – Conclusions
• Thermotolerant coliforms
– Relatively low levels on water spinach (<104/g)
– No apparent differences between seasons
• Protozoan parasites
– Higher prevalences during dry season at WW-site
– Giardia is most prevalent, particularly at WW-site
– Cryptosporidium: high levels during dry season at WWsite
– Cyclospora is less prevalent than Giardia and
Cryptosporidium, but is present at both sites and during
both seasons
• Helminth eggs
– Very low levels detected at both sites, no apparent
difference between seasons
Study completion and remaining
work
• Data analysis
• PCR analysis for
identification and
characterization
puruposes; and
subtyping of
protozoans
• Preparation and
submission of
manuscripts (1-2 MS)
Acknowledgements
• Staff of the Faculty of Fisheries, at the Royal
University of Agriculture, in particular Chouk Borin,
and at the Pasteur Institute in Phnom Penh for
excellent technical assistance in sample and data
collection
• The National Inst of Hygiene and Epidemiology
(NIHE) for providing laboratory facilities and good
laboratory support for sample analyses
• EU-INCO-DEV (PAPUSSA), DANIDA (grant no.
104.Dan.8.L ”Sanitary Aspects of Drinking Water
and Wastewater Reuse in Vietnam”) and KVL for
financial support