STUDIES ON A SMALL COLLECTION OF PLANORBID
SNAILS FROM SOUTHERN SOUTH AMERICA
F re d e r ic o S. B a rb o sa a n d D a lv a A . M ello
Snails belonging to
B iom ph alariagenus were collected from some regions of
Southern
South America as follows: Resistencia, province of Chaco, Argen
tina; Assumpcion, Paraguay; Departm ent of Maldonaão of Caneloni, Vruguay;
anã Pôrto Alegre, Rio Grande do Sul, Brazil. The m aterial was classified as
B iom ph alaria peregrina (
Orbigny
)
twice from Uruguay and once in Brazil;
B. ten a g o p h ila(Orbigny), from Argentina and Brazil; anã
B. stram in ea(Dwnker)
in Paraguay.
Negative results were obtaineã from the exposition of the abone refer-
eã snail specimens to miraciáia of
S. m an son ifrom Pernambuco, Brazil.
D uring th e m o n th o f January 1969 th e junior A uthor tra v ellin g in Southern S outh A m erica, m ad e a lim ited num ber o f •ccllections o f fresh -w a ter sn a ils b elon g in g to th e Planorbid gen u s
Biomphala
ria.
P art of th e sn a ils w a s exten ded w ith m en th o l crystals and fix ed locally in a l-coh ol 70%, w h ile som e oth er sp ecim ens were b rou ght alive to th e laboratory in R ecife w here th e present stu d ies were m ad e. U pon arrival th e alive sn ails were p u t in ta n k s to breed.
P reserved sn a ils were dissected for cla ssif ic a tio n . A live sn a ils w ere each exposed to ten m iracidia of a local strain o f
Schistosoma mansoni.
In ali th e in -fectio n ex p erim en ts a h ig h ly suseeptible stra in ofBiomphalaria glabrata,
from P a u lista (P ern a m b u c o ), w as used as c o n tr o l.S n ails exposed to th e in fectio n were k ep t in ta n k s and exam in ed for cercariae by exp osition to a strong source of lig h t b eg in n in g th e 20th d ay a fter th e in fectio n
A fter 40 days th e sn a ils were crushed and exam in ed for in fectio n .
T h e tem perature o f th e w ater, during the experim ents, varied from 24 to 26°C. T he follow in g stu d ies and observations were m ad e.
PARAGUAY
T w en ty -o n e sn ails w ere collected in drainage d itch es in th e streets of “B air ro Capitalizador” , A ssum ption. T he water in th e d itch es w as dark, h ig h ly polluted and th e bottom w as m uddy. Aquatic plants were n o t p r e s e n t. T he h a b ita t w as not p erm an en t since th e w ater w as m ainly origin ated from periodical rain s fallen few days b efore. S n ails of th e genus
Po-
macea
(A m pulariidae) were seen thrivingalong w ith th e
Biomphalaria.
T he shell . and th e an atom y of th e sn ails collected correspond to th e speciesBiomphalaria
straminea
(D u n k e r ). T h a t species in know n from V enezuela, th e G uianas and B razil, reach in g to ab out 20°S. I t w as recen tly found in Colombia (1) . The266
Rev. Soc. B ras. Med. Trop.
Vol. I II — N .° 5
species is for th e first tim e recorded in P aragu ay.
The exposition of 17 sp ecim ens of th e Paraguay strain of
B. straminea
to m ir-acidia ofS. mansoni
resulted negative: none of th e sn ails got th e in fectio n .ARGENTINA
A collection of sn a ils w as m ad e in th e tow n of R esistencia, cap ital of th e prov-ince of Chaco, n orth ern A rgen tin a. S n ails were collected in a large sw am p a t th e end of Street B razil in th e outskirts o f th e tow n. T he h a b ita t seem ed to be p erm an-ent: th e w ater show ed h ig h turbidity an d several aquatic p la n ts were p resen t. Other sn ails fou n d were sp ecim ens of
Drepanotrema
sp . (P lanorbidae) an d ofPomacea
sp (A m p u lla riid a e ). T he sp ec im ens o fBiomphalaria
collected w ere cla s-sified asB. tenagophila
(O r b ig n y ). T his species was alread y k now n from A rgentina, Paraguay, U ruguay, B razil (about 15.° so u th w a rd ), B olivia and Peru ( 7) .T he exposition of 18 sp ecim ens of th e Argentina strain o f
B. tenagophila
to m iracidia of S.
mansoni
gave n eg a tiv e results.URUGUAY
Two collections were m ad e in th is cou n -try: one in th e tow n o f S a n Carlos (D e p artam ento de M aldonado) an d oth er about 20 km n orth ern of M ontevideo (D e partam ento de C a n e lo n i). T h e sp ecim en s of M aldonado were collected in a sm all ditch in a Street n ear th e cen ter of th e sm all tow n of S an C arlos. T he sn ails were livin g in a sm a ll tem porary pooJ w ith ou t aquatic p la n ts an d w ith no oth er sn ails. T he bottom w as clayey. T he sn a ils from C aneloni were found in a p erm anent stream know n as Toledo C hico. T h e w ater w as clear, th e bottom m uddy and m an y aquatic p la n ts were p rese n t. O ne specim en o f
Lymnea
s p . w as fou n d am on g th e planorbids. S n ails from b oth p laces in Uruguay were cla ssified asBiomphalaria
peregrina
(O rb ig n y ): 22 sp ecim ens were collected in M aldonado an d 56 sp ecim ens in Caneloni. T he sp ecies h a s large g eo-g ap h ical distribution. I t h a s b een recorded from Ecuador, B olivia, Chile, Brazil, Paraguay, Uruguay, and A rgen tina w est of th e Andes from about th e Equator to 42.° S, and ea st of th e Andes from about 15.° to 41.°S (8) .
N egative results were obtained from th e exp osition o f 17 sn a il sp ecim en s of
B. pe
regrina
from M aldonado and 1 sp ecim enfrom C aneloni to m iracidia of
S. mansoni.
BRAZIL
One co lle c tio n was m ade in th e Southern B razilian sta te o f R io G rande do S u l. The place collected w as near th e airport of Porto Alegre w here tw o sp ecies of
Biomphalaria
were fo u n d . T h e h a b ita t is an ex ten siv e p erm a n en t sw am p located at th e edgde o f th e h ig h w a y lea d in g to th e airport. T he w ater show ed som e turbidity, th e b o ttcm w as m uddy and m a n y aquatic p la n ts were p resen t. S n ails of th e fa m ilies P h ysid ae an d A m pullariidae were fo u n d . Num erous em pty sh ells o fBiomphalaria
tenagophila
(O rbigny) plus 3 alive sp ecim en s ofB. peregrina
w ere co llected . Of th o se on ly on e sp ecim en w as a liv e w h en arrived in R ecife. T h is specim en w a s ex -posed to m iracidia o fS. mansoni
an d w as fou n d dead few days la tte r . O bviously th e cla ssifica tio n o f b oth sp ecies w as m ade by sh ell fea tu res.COMMENTS
Tw o sp ecies represen ted in th e sm all collection o f planorbid sn a ils stu d ied in th e p resen t paper are w ell know n as v ec-tors o f sch isto so m ia sis m an son i:
B. stra
minea
ch iefly in n o rth ea stern B razil andB. tenagophila
in th e so u th e m p a rt of th is cou n try.B. peregrina
ca n be co n -sidered as a p o ten tia l vector of S c h is tosom iasis according to laboratory in fe c tion d ata given by B arbosa, B arbosa & Rodriguez (5) for sp ecim en s from Ecuador, by R ichards (9) for sp ecim ens from P uer-to Rico, an d by P araense & Correa (7) for sp ecim ens from P araná, Brazil.O ther p o ten tia l in term ed iate h o sts of
S et.-O u t., 1969
Rev. Soc. Bras. Med. Trop.
267
R esu lts p resented in th e current paper do n o t exclu de th e p ossib ility th a t th e sn ail strain s used for th e in fec tio n experim ents could serve as p o ten tia l in term ed iate h osts for sch isto so m ia sis.
The cap ab ility of a sn a il to a c t as a su itable h o st depends on b oth sn a il and p arasite.
B. straminea,
th e w ell know n vector o f sch istosom iasis in n orth easternBrazil, b eh ave d ifferen tly in north ern South A m erica w h en subm itted to labor-atory in fectio n s. Barbosa (2) recently show ed th a t
B. straminea
from Manaus, Brazil, was fully resista n t to th e infection w ith S .mansoni
from Pernam buco and th a t th e stra in of th e sam e sn ail species from Cali, Colom bia, (1) could be hardly in fected w ith S .mansoni
from th e sam e o rig in .R E S U M O
Caramujos do gênero
B iom ph alaria (Planorbidae) foram coletados ao
sulda América do Sul, nos seguintes locais: Resistência,
'província do Chaco,
Argentina; Assunção, capital do Paraguai; províncias de Maldonado e de Ca
neloni, Uruguai; e Pôrto Alegre, capital do estado do Rio Grande do Sul,
Brasil. O m aterial foi classificado como se segue:
B iom ph alaria peregrina(
Or
bigny)
i,
duas coletas no Uruguai e uma no Brasil;
Bi. ten a g o p h ila(O rbigny),
na Argentina e
no Brasil; e
B . stra m in ea(Dunker), no Paraguai.
iResultaram
negativas tôãas as ten tativas feitas em laboratório para in
fectar as espécies acima mencionadas com a cêpa de
S ch istosom a m an son ide
Pernambuco.
R E S U MO
1. BARBOSA, F . S . —
Biomphalaria
stram inea
(Dunker) en C olom bia.Antioquia Medica,
18: 753-758, 1968.2. BARBOSA, F . S . — A n o te on
Biom
phalaria straminea
(D unker, 1848)from M anaus, sta te of Am azonas, B razil.
Rev. Soc. Bras. Med. Trop.,
2: 77-78, 1968.
3. BARBOSA, F . S . & BARBOSA, I. —
Tropicorbis chilensis
from S an tiago, Chile, a p o ten tia l in term ed iate host o fSchistosoma mansoni. Boi. Chile
no Parasitol.,
13: 7-9, 1968.4. BARBOSA, F . S ., BARBOSA, I. & CARNEIRO, E. — D escrip tion of
Aus-
tralorbis sericeus
(D u n k e r ), a pos-sible in term ed iate h o st ofSchistoso-
m a
mansoni
in Ecuador.Ann. Trop.
Med. Parasitol.,
57: 52-58, 1963.5. BARBOSA, F . S . BARBOSA, I. & RODRIGUEZ, J . D . —
Tropicorbis
philippianus
(Dunker) a p o ten tia l in term ed iate h o st of
Schistosoma man
soni
in E cuador.Jour. Parasitol.,
44: 622, 1958.
6. CRAM, E. B ., JONES, M. F . & W RIGHT, W. H. — A poten cial in ter m ediate h o st of
Schistosoma manso
ni. Science
: 101: 302, 1945.7. P . A . H . O . — A Guide for th e Iden tific a tio n of th e S nail H osts of S ch is tosom iasis in th e A m éricas. S cientific P u blication N.° 168. W ashington. D . C . , U . S . ., 1968.
8. PARAENSE, W. L. — T he synonym y an d distribution of
Biomphalaria pe
regrina
in th e Neotropical region.Rev. Brasil. Biol.,
26: 269-296, 1966.9. RICHARDS, C. S. In fectivity of
