J. Parasitol., 87(4), 2001, p. 906–907
? American Society of Parasitologists 2001
Prevalence of Neospora caninum Infection in Dogs From Beef-Cattle Farms, Dairy
Farms, and From Urban Areas of Argentina
W. Basso, L. Venturini, M. C. Venturini, P. Moore*, M. Rambeau, J. M. Unzaga, C. Campero*, D. Bacigalupe, and J. P. Dubey†, Catedra de
Parasitologia, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, 60 y 118, 1900 La Plata, Argentina; *Instituto Nacional de
Tecnologia Agropecuaria, Balcarce, Argentina; and †author for correspondence at United States Department of Agriculture, AgriculturalResearch
Service, Animal and Natural Resources Institute, Parasite Biology, Epidemiology and Systematics Laboratory, Building 1001, BARC–East,
Beltsville, Maryland 20705-2350
termined in sera of 320 dogs from Argentina using the indirect fluores-
cent antibody test (IFAT). Antibodies to N. caninum were found in 121
of 320 (37.8%) sera with titers of 1:50 (21 dogs), 1:100 (23 dogs), 1:
200 (23 dogs), 1:400 (17 dogs), 1:800 (23 dogs), and ?1:1,600 (14
dogs). The seropositivity (IFAT, ? 1:50) was higher in dogs from dairy
(48% of 125) and beef (54.2% of 35) farms than in dogs from urban
areas (26.2% of 160). Prevalence of anti-N. caninum antibodies was
higher in dogs more than 12 mo of age (47.7%, 105 of 222) versus in
12-mo-old or younger dogs (12.7% of 86), suggesting postnatal expo-
sure of N. caninum infection in dogs.
Prevalence of anti-Neospora caninum antibodies was de-
Neospora caninum is an important cause of mortality in dogs
and cattle in many countries including Argentina (Dubey and
Lindsay, 1996; Dubey, 1999; Venturini et al., 1999; Lindsay
and Dubey, 2000). Until recently, vertical transmission from
mother to fetus was thought to be the main route of transmis-
sion of N. caninum in cattle and dogs (Dubey and Lindsay,
1996). In 1998, the dog was identified as a definitive host of
N. caninum (McAllister et al., 1998). However, the role of the
dog in the epidemiology of N. caninum infection is not fully
known because only a few oocysts are shed, and N. caninum
oocysts have not been identified in the feces of naturally in-
fected dogs (Lindsay et al., 1999; Dubey and Lindsay, 2000).
Studies from Canada, Japan, and The Netherlands, have re-
ported a positive relationship between dogs and bovine neos-
porosis (Pare ´ et al., 1998; Sawada et al., 1998; Wouda et al.,
1999). Therefore, the prevalence of N. caninum antibodies was
compared in dogs from urban and rural areas in Argentina.
Sera of 320 dogs were examined for the detection of anti-N.
caninum antibodies using the indirect immunofluorescence an-
tibody test (IFAT) with culture-derived tachyzoites of the NC-
1 isolate and rabbit anti-canine IgG conjugate (Sigma, St. Louis,
Missouri) (Dubey et al., 1988). Sera were tested by IFAT at 2-
fold dilutions, beginning at 1:50. One hundred sixty sera were
from dogs seen in veterinary hospitals in urban areas, 151 of
them with data concerning presence or absence of neosporosis-
related neurologic signs. One hundred twenty-five sera were
from dogs from 23 dairy farms located in the Province of Buen-
os Aires, 1 in the province of Jujuy, 3 in the province of La
Pampa, and 1 from Tierra del Fuego. Thirty-five sera were from
dogs from 10 beef cattle farms in the province of Buenos Aires.
Sex was known for 317 dogs, age for 308, and breed for 314
dogs. Results were analyzed by the chi-square test (Stalcat,
Antibodies to N. caninum were found in 121 (37.8%) of 320
dogs with titers of 1:50 (21 dogs), 1:100 (23 dogs), 1:200 (23
dogs), 1:400 (17 dogs), 1:800 (23 dogs), 1:600 (9 dogs), 1:
3,200 (3 dogs), 1:6,400 (1 dog), and 1:52,500 (1 dog). The
prevalence of antibodies (IFAT, ? 1:50) was higher in dogs
from beef (54.2% of 35) and dairy (48% of 125) farms than
from dogs from urban areas (26.2% of 160); the differences
were statistically significant (P ? 0.001). Of the 153 urban
dogs, the seroprevalence in males (28.1% of 71) was not sta-
tistically different (P ? 0.86) from that in females (25.6% of
82). Of the 153 dogs with breed data, seroprevalence was
23.9% of 117 in purebred dogs versus 36.1% of 36 crossbred
dogs (not significant P ? 0.21). The antibody titers in dogs
with clinical signs were not different from those in dogs without
reported clinical signs. Prevalence of antibodies increased with
age of the dog with seroprevalence of: 13% of 46, ?12-mo-
old; 12.9% of 31, 13–24-mo-old; 34.3% of 32, 25–48-mo-old
dogs; and 45.4% of 44, 49-mo or older dogs (significant P ?
Prevalence of N. caninum antibodies was significantly higher
(P ? 0.001) in dogs ?12 mo of age (60.9% of 87) versus ?12-
mo-old dogs (9.6% of 31) from dairy farms. Although the num-
ber of dogs from beef farms was low, similar trends were ap-
parent; antibodies to N. caninum were found in 2 of 9 (22%),
12-mo-old or younger dogs versus 17 of 28 (60.7%) dogs older
than 12 mo from the beef farms. Overall, prevalence in 12-mo-
old or younger dogs (12.7% of all dogs of known age) was
significantly lower (P ? 0.001) than in dogs older than 12 mo
(47.7% of 222).
The seroprevalence of N. caninum in dogs in Argentina was
higher than in dogs from other countries. Overall, N. caninum
antibodies were found in 37.8% of 320 dogs in this survey and
in 47.4% of 97 adult dogs in a previous survey from Argentina
(Di Lorenzo et al., 1997). Most surveys reported from other
countries were from urban dogs. Even in urban dogs from Ar-
gentina, the prevalence was 26.2%, which is higher than 2% of
229 dogs from Kansas (Lindsay et al., 1990), 7% of 1,077 dogs
from 35 states in the U.S. and 3 provinces in Canada (Cheadle
et al., 1999), 17% of 163 dogs from England (Trees et al.,
1993), 6% of 104 dogs from North Mymms (Lathe, 1994),
0.5% of 398 dogs from Sweden (Bjo ¨rkman et al., 1994), 11%
of 360 dogs from Belgium (Barber, van Ham et al., 1997),
15.3% of 98 dogs from Denmark (Rasmussen and Jensen,
1996), 22% of 200 dogs from New Zealand (Reichel, 1998),
9% of 451 dogs in Australia, 20% of 414 dogs from Uruguay,
0.2% of 500 dogs from the Faulkland Islands, 0 of 140 dogs
from Kenya (Barber, Gasser et al., 1997), 29% of 194 dogs
from Italy (Cringoli et al., 1996), and in 30 of 150 (20%) of
dogs from Turkey (Cos ˇkun et al., 2000). Most of these surveys
were based on an IFAT titer of ?1:50. Thus, results should be
RESEARCH NOTES 907 Download full-text
Only 2 previous surveys compared the prevalence of N. can-
inum in urban and rural dogs. Sawada et al. (1998) reported N.
caninum antibodies in 31% of 48 dogs from dairy farms and
7% of 198 dogs from urban areas in Japan. Wouda et al. (1999)
reported a higher prevalence in farm dogs (23.6% of 152) ver-
sus urban dogs (5.5% of 344) from The Netherlands, which is
in agreement with results of the present study from Argentina.
Increasing rates of prevalence of N. caninum antibodies in
older dogs in the present study indicate postnatal exposure of
this parasite. Cattle are economically important to Argentina’s
economy. Whether dogs on cattle farms are the source of some
of N. caninum infections in cattle or whether both cattle and
dogs are infected from a common source needs investigation.
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? American Society of Parasitologists 2001
Monogeneans in Introduced and Native Cichlids in Me ´xico: Evidence for Transfer
M. I. Jime ´nez-Garcı ´a, V. M. Vidal-Martı ´nez, and S. Lo ´pez-Jime ´nez*, Laboratorio de Parasitologı ´a, CINVESTAV-IPN Unidad Me ´rida, Carretera
Antigua a Progreso Km. 6, A.P. 73 ‘‘Cordemex,’’ C.P. 97310, Me ´rida, Yucata ´n, Me ´xico; *Laboratorio de Parasitologı ´a. Divisio ´n Acade ´mica de
Ciencias Biolo ´gicas. UJAT. A.P. 983, C.P. 86101, Admon. de Correos No. 2. Col. Atasta de Serra, Villahermosa, Tabasco, Me ´xico
lasoma callolepis and C. fenestratum, and 2 introduced African cichlids,
Oreochromis aureus and O. niloticus, from 3 localities in southeastern
Me ´xico for monogeneans. Six monogenean species infected the African
cichlids: Cichlidogyrus haplochromii, C. dossoui, C. longicornis lon-
gicornis, C. sclerosus, C. tilapiae, and Enterogyrus malmbergi. We
found all these parasite species, except C. haplochromii and C. dossoui,
on the native C. fenestratum and C. callolepis. Prevalences of Cichli-
dogyrus spp. were 3–10% and abundances ranged from 0.03 ? 0.2 to
0.1 ? 0.3 for native cichlids. We only recovered a single E. malmbergi
from 1 C. callolepis. We found Sciadicleithrum bravohollisae, a mono-
We examined 2 cichlid fish species native to Me ´xico, Cich-
genean of native Cichlasoma spp., on the gills of the introduced O.
aureus from Lake Catemaco (prevalence 3%, abundance 0.03 ? 0.2).
Although prevalence and abundance in atypical hosts were fairly low,
the present findings provide evidence of monogenean transfer from Af-
rican to American cichlids and vice versa. This is the first record of
exotic monogeneans in the genus Cichlidogyrus and Enterogyrus in-
fecting native American cichlid fish. It is also the first record from
southeastern Me ´xico of a native American monogenean infecting intro-
duced African cichlids.
Several cichlid fish species in the genus Oreochromis and