4-
't_ffi-fr,lw
HtF
ra++a!F+tE)
Hon Mei
BIOLOGICAL
INVADERS AS
ANOTHER
DISASTER:
"FUSHOU''
SNAILS
AND
ANGIOSTRONGYLUS
CANTONENSIS
INFESTATION
After taking
half-cooked
"Fushou"
snails,23
people
in
Beijing
were afflicted by
a
new parasite,
Angiostrongylus cantonensis, with
rats being the
"principal"
host and
the
"Fushou" snails, the "intermediate"
host;
important
"carrier"
hosts are
fresh water shrimps, fishes and
frogs.
With ingestion of
raw
snails, fish or
even
lettuce, the parasite invades
our
central
nervous
system, e.9.,
"eosi-
nophilic meningitis" has an
incuba-
tion
period of up to 36 days, usually
presenting
as
headache, dizziness,
fever, facial
numbness,
nerve
palsies,
etc.
"Fushou"
snail
(Amazonian
snail,
apple
snail
or
Ampullaria gigas spix) is indigenous
to
South America, but was imported
to China
in
the
1980s as a
gourmet
item. With surplus being disposed of
in
the
wilderness
and
rapid
multiplication, rice and other aquatic
crops
are
attacked,
e.9.,
in
Guangdong,
Guangxi,
Fujian,
Yunnan, etc.,
causing enormous eco-
nomical loss. Control is ditficult:
by
literal
hand-picking
snails;
rearing
ducks to feed on young snails
and
specilic chemicals
to
poison them.
Better
to control over
imports of ex-
otic species of plants and animals to
prevent
further
environmental
disasters.
^Eewffi#&HH
#m#SHFsffi#
il8
E'
-ffi
FEizhF0
Rffi
&ffiZ'8ffi+-FtilgE[f,f,
*
ffi
"
W#)bB
fi
ffi4L
H
^ffi
)btr-H7htrlL#flil&Fr{€
E[f,*
*ffirFfif '
&tuWffi#wfrg'
fish#tF&+.
"
4G
.
a\
tr
-
an*ffi
Fl
F0
H
)b'
+EiltnR&#fi
F9#ru|FE'.-66m
##f
"-L
"
6#€
')bfrffizs€Htll€Efl#SfiJf,#EEH
fr
AIH
T
*trfi
,l#*
r0ffi
#urzf
*ffi
F0 "
iA
+
*P.
t!
*'tr
?E-=4EF!H
+
@
,\€H
-t
H!
-rfr
E
E
g.+
+
H!tr
e
"f
s
&;+
,1R*
AfrT*IE'
€E.€WJfr'F+
HiEtE'
ME++F1TH'I.
E
l
iE
Ht,
rE
+ H
"i# Jt
t
+R"'Ie,
e
FXHE
g
H!
,^..{A
H E
EWJ
Z
-o
iE#4R(Amazonian
smail
i
Ampullaria gigas
spix)X€ttfi
$E
'
H++E
'
E-fEm+=iftzjcFfrFPtW.EWJ'
2-HtEH!fi#frtWJ
F5'
EF,EflfiJ' fE4RFl
"
lE-#$BtrETH-)rtlEE,ffi,6tFJ,ftr4'
.tt
3d70+1\11
,^.+
EE,€'
80+,ftx
H
E,tr#+
H,\.El
,\ER'
if
F#lffEtE
.
HD$iEEE'H
'
fittrrfiT*T'
E?fi*+ilFlgTrl'
'
if
fR+*E'HT*
"
ffizKEff*rl'
EfiHmE
.
+E-1+
-
EH'ffif,]f;Fe€ft&frlEF€-E
frW
"
I,AF.teHI,IJ'
FT+ETEIiE€TH?€-#4R:(E
,
|effiM+)EEF!
it'
,\$E++tffi
'
1(#iTffi)dE
"
#F{f,Fl'
+@Ht6€'fi9
ttrEHlzlcr4(td.
)ff
.
z]<Eif)T9F$1oHAtF "
HIS?E-#4RiEffi
ftE,
?&+t
H til
j\
E
+fb
a-'
ffi.
f!
rl'X
'{E€-
E
EWJ
.
€-
EE
€
a
ffi
f*
#
a
E
EH
*H
f&
(
FAo
)
B
F#
tE
+U,{R
#
a\ ftt
(
I
p p
c
)
H!
+
FJ'
gf
tE-=
$E
#tj
7
e
Ei
JR
h
;+'ff,
'
ffi
R
#
Fv,+a+a
E
tE
+t
E
t
El3
2-
1&
E
E
tH'
Yf+t@rJ<#itEd
fr&^'
nE
trJ'f+ffi,^.ffiIRJF
.
Eilie-=$tffi
*
Ht
+trfrffi
Ei
Ht
Jnh'
€'
EE*lrF5
*
+X-
H
E
ffi
&
ffi
*
gf
lE-
#
4R
H!
FE'
)h
t
t*
f
n
E
ft
tJ
+H
ffi
"
rE
tr
=
fi
E
ffi r&
E,
H**t3
F5
#H
BEE.f
b
g*q$Egj .
E
ryF€4R
.
ffi
$Efi5qF
St=t
#li
fsfr
h
"'f
E
EEllL
lEl
E+'
lE-=$,Bifi
4F
HA.
Hfr
+t)J
1l#1e,
Effi.*
r&;E-H/(.r€tH'
*
+*1'nE+H
H
rEtE,\,lFS
H!€F-t
"
W*ffi)ie
@r.*-&,t'a
EthlHEil#Rffi,F'
x
€
trm{+Yvf,ffiffip=*1tflEH4'
E-E
Atsttt
F.
H!
B E
ffi
,F'
S
E',hl'l
€
E
ffi ffi
(
A
n
g
i
o
s
t
ro
n
s y
I
u
s
cantonensis)
4rJ
ffi
F
tlE
f!
+
ffi
74
f$^ffi11fi9
"
EEJfi
H!
;g'f
HE
H3-36x,
*frtott
"
r'FlF.AEWIed€94'E+EpHtr'F
.
H
,L'trG'
E.,IJ)F
HE*trHAH
AF
R
.
+]E
OE€f
ffi
{Ud
E
ftHA,
*
H.E.AA,EE,F
'
+HEt
E9F'F
'
H€-seE
.
?FR'tr*l3i+f,g
