Vol.2, No.11, 1316-1319 (2010)
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
The frequency of intestinal parasites in puppies from
Mexican kennels
Enedina Jiménez-Cardoso1*, Leticia Eligio-García1, Adrián Cortés-Campos1,
Apolinar Cano Estrada1, Margarita Pinto-Sagahón2, Cynthia Noguera-Estrada2
1Laboratorio de Investigación en Parasitología, Hospital Infantil de México FG, Dr. Márquez No. 162. Col. Doctores, D.F. 6720,
México; *Corresponding Author: enedina@servidor.unam.mx;
2Fort Dodge Animal Health, Fort Dodge, USA.
Received 7 August 2010; revised 18 August 2010; accepted 30 August 2010.
The purpose of this investigation was to deter-
mine the intestinal parasite prevalence in pup-
pies from six different kennels; four kennels
were in Guadalajara and Zapopan cities (Jalisco
State) and two kennels were in Mexico City.
From October 2006 to November 2007, we col-
lected 441 fecal samples from 147 puppies, both
male and female, ranging from 1 to 36 months of
age. Three samples from every puppy were ana-
lyzed by using the Faust technique. The preva-
lence found were as follows: Giardia intestinalis
(genotype A and B) 6.8%; Cystoisospora 21.08%;
Uncinaria 7.48%; Toxocara canis 12.29% and
multiparasitism (Giardia, Toxocara and Unci-
naria) 4.76%. The highest prevalence for both
Giardia and Cystoisospora were found in 2-3-
month-old puppies; the highest prevalence for
Toxocara canis was found in 3-4-month-old pu-
ppies. In the kennels of Mexico City we found
mainly Giardia intestinalis, Cystoisospora to be
most prevalent in Zapopan and Toxocara canis
in Guadalajara. The high prevalence of intestinal
parasites found in this study demonstrates an
increased risk for infection in humans, as these
animals are usually a common pet in many
homes. This zoonotic phenomenon represents
an important health problem for any community.
Keywords: Parasites; Giardia; Cystoisospora;
The prevalence of intestinal parasites in dogs from
kennels depends on several variables, including the ken-
nels’ geographic area, number of animals sharing space,
and, most importantly, the sanitary conditions in which
the dogs live. Epidemiological studies of intestinal para-
sites give us an idea of the zoonotic risk for dogs living
in kennels as well as dogs living with a family as a do-
mesticated pet.
Several studies from kennels in Australia showed a
parasitic prevalence of 23.9%, with 9.3% of the cases
testing positive for Giardia intestinalis [1]. In Spain, a
study showed a prevalence of parasites in 25% of those
tested, with 6.0% of the cases testing positive for Toxo-
cara canis and 10.0% testing positive for Cystoisospora
[2]. In Greece, studies found a 26% parasitic prevalence,
with 12.8% of the cases testing positive for Toxocara
canis, 4.3% testing positive for Giardia duodenalis and
Cystoisospora, and 2.8% testing positive for Uncinaria
[3]. These statistics are important, as multiple parasites
are being found in puppies as young as six months;
therefore, kennel owners should treat all of their animals
for parasites to prevent the continued spread of gastroin-
testinal diseases [4]. For example, there is a high inci-
dence of Giardia in children; this could be explained if
the children are living in homes with a contaminated pet
[5]. Deworming and treating all kennel animals for para-
sites would reduce the cases of infection in humans.
When puppies lived in a small, confined area in
groups of 12 to 15, especially in cases when they lived
together with their mother, tests showed a high preva-
lence for Toxocara canis and Cystoisospora (36.4%). In
contrast, when puppies were kept in clean, spacious ar-
eas, these parasites were found in only 10% of those
tested. Finally, some reports show that the prevalence of
intestinal parasitism in dogs ranges from 35.5% to 100%
[6]. For dogs kept in private kennels, the prevalence
range is between 54% and 68% [7].
Intestinal parasitism can be an asymptomatic disease;
moreover, there is no a specific symptom that can iden-
tify a parasite. Therefore, all puppies kept in a kennel or
stored in similar places could receive a prophylactic
treatment to prevent intestinal parasitic from spreading
E. Jiménez-Cardoso et al. / HEALTH 2 (2010) 1316-1319
Copyright © 2010 SciRes. http://www.scirp.org/journal/HEALTH/Openly accessible at
to children who have puppies at home [8]. We therefore
conducted this investigation to elucidate the intestinal
parasite prevalence in different kennels located in Mex-
ico City and Jalisco State, with the hope of reducing the
possible risk factors associated with human-puppy para-
sitic diseases.
Identification and Prevalence of Parasites: From Oc-
tober 2006 to November 2007, we collected feces from
147 puppies (males and females) ranging from 1 to 36
months in age and obtained from six kennels, four of
which were in Guadalajara and Zapopan cities (Jalisco
State) and two of them were in Mexico City. The dogs
were fed at libitum and they received no special care in
their environment. We collected three samples from each
animal on different days. Identification of the parasites
was performed via the Faust technique [9], and the re-
sults were analyzed in relation to the dogs’ ages, sexes,
breed sizes and kennels. We considered data statistically
significant when p < 0.05 with 95% confidence interval
(CI), using SPSS 10-0 (Copyright 1999, SPSS Inc. pro-
Genotype of Giardia: DNA was isolated from each
puppy’s fecal sample by using the fast DNA kit and the
fast prep instrument (QBiogene, inc., CA). Then B-giardin
gene from Giardia intestinalis was amplified using the
nested-PCR method [10]. After PCR, electrophoresis in
1.5% agarose gel was performed. Next, in a 10 µL reac-
tion volume, restriction digest reaction contained 7 µL of
amplicon obtained from the nested-PCR reaction, 10
mg/mL BSA and 10 U of HaeIII enzyme [11]. We incu-
bated this reaction mix at 37 for 3 hours, and then
analyzed the product using 2% agarose gel electrophore-
sis to determine the fragments obtained.
Identification and prevalence of parasites: The preva-
lence of Giardia intestinalis in dogs at different ages was
4.69%-6.8%, (95% CI, 2.11 to 11.49), as is seen in Table
1. The highest prevalence occurred in dogs that were 2-3
months old. A statistical difference was observed be-
tween groups: those groups with dogs older than 3 mon-
ths and those groups with dogs older than 11 months (p
< 0.05). In the same table, we have demonstrated that in
Mexico City, kennel-housed animals had the highest
rates of Giardia intestinalis (p = 0.003). Other analyses
did not show any statistical differences between breeds
or breed size, while the location of kennel housing was
important. The prevalence of both Cystoisospora and
Toxocar a in the puppies of Mexico City kennels was
Table 1. Prevalence of Giardia intestinalis in dogs from dif-
ferent ages and kennels.
Giardia intestinalis
Age months Total N (+) 95% CI p-value
< 1-2 56 1 1.78-16.75
> 2-3 48 6 12.50-9.35 0.029
> 3-4 23 1 4.34-8.33 N.S.
> 4-5 8 0 0 -
> 5-11 5 1 20-35.06 0.04
> 11 7 1 14.28-25.92 N.S.
Total 147 10 2.11-11.49
Jal 47 2 4.24 ± 5.77
Zapopan, Jal 28 0 - -
Mexico City 72 8 11.11-7.25 0.003
Total 147 10 6.80-4.07
Breed size
Small 76 3 3.94-4.37 N.S.
Medium 43 5 11.62-9.58 N.S.
Large 28 2 7.14-9.53 N.S.
Total 147 10 6.80-4.07
N (+): Number of positives cases; 95% Confidence interval; P > 0.05; N.S.
Non significant
statistically unique. As seen in Table 2, we analyzed dogs
2-3-month old dogs and 3-4 month-old dogs. Multiple
parasites were isolated in dogs older than 2-3 months old
(p < 0.002). Finally, Table 3 shows what parasites were
prevalent in each kennel. The highest infestation rate in
Mexico City was for Cystoisospora, and Toxocara was
highest in Zapopan (p < 0.001). In Guadalajara, most
cases showed a high prevalence for multiparasite infec-
tions. Notably, other analyses did not show statistical
differences in breed and sex.
The Genotype of Giardia: as shown in Figure 1 one
Giardia isolated was Genotype A2 and nine isolates
were Genotype A1.
The prevalence of Giardia intestinalis in puppies from
Mexican kennels was 6.8%, with the highest value in
dogs younger than 6 months old. Similar results have
een published by others [6,12-14] However, a good b
E. Jiménez-Cardoso et al. / HEALTH 2 (2010) 1316-1319
Copyright © 2010 SciRes. http://www.scirp.org/journal/HEALTH/
Table 2. Prevalence of Cystoisospora, Toxocara and Uncinaria isolated from puppies in different ages.
Cystoisospora Uncinaria Toxocara Multiparasites: (Giardia,
Toxocara and Uncinaria).
(months) (+)/T 95% CI p (+)/T 95%CI p (+)/T95% CI p(+)/T95% CI p Neg/T%
< 1-2 3/56 5.35 ± 5.89 NS 0/56 0 - 7/5612.5 - 8.66NS0 0 - 46/5682.16
> 2-3 14/48 29.16 ± 12.85 0.003 8/48 16.66 ± 10.54NS8/4816.66 - 10.54NS5/4810.41 - 8.64 0.002 13/4827.08
> 3-4 11/23 47.82 ± 20.41 NS 2/23 8.69 ± 11.51NS2/238.69 - 11.510.01 - - - 8/2334.78
> 4-5 2/8 25 ± 30 NS 1/8 12.5 ± 22.91NS2/825 -30 NS2/825 - 30 NS 1/8 12.5
Total 30/135 21.08 ± 6.59 11/135 7.48 ± 4.25 19/13514.07 - 5.42 7/5612.5 -3.44 68/13550.37
(+): positives cases; T: total; 95% Confidence interval; P > 0.05; N.S. Non significant
Table 3. Prevalence of multiparasites found in each kennel.
Cystoisospora Uncinaria Toxocara Multiparasites: (Giardia,
Toxocara and Uncinaria).
Kennel (+)/T CI ± 95% p1 (+)/T CI ± 95%p1(+)/TCI ± 95%p1 (+)/TCI ± 95% p1 Neg/T%
Jalisco 10/17 21.27 ± 11.7 NS 0 - -0 - - 1/472.12 ± 4.1 0.03 36/47 76.59
Jalisco 15/28 53.57 ± 18.4 NS 2/28 7.14 ± 9.53NS1/283.57 ± 6.80.001 2/287.14 ± 9.5 NS 8/28 28.57
Mexico City 6/72 8.33 ± 6.38 0.001 9/72 12.5 ± 7.63NS18/7225 ± 10 NS 4/725.55 ± 5.2 NS 35/7248.61
Total 31/147 21.08 ± 6.5 11/147 7.48 ± 4.25 19/14712.92 ± 5.4 7/1474.76 ± 3.4 79/14753.74
(+): positives cases; T: total; 95% Confidence interval; P > 0.05; N.S. Non significant
Openly accessible at
Figure 1. Genotype of Giardia intestinalis using B-giardina
gene. MW - Molecular weights; CA Amplification control;
Lane 1.- Genotype A2; Lanes 2-10 Genotype A1.
analysis should consider the following factors at least:
geographic area; whether the kennel is private, public, or
a business; number of animals living in the same space;
hygiene standards; and feeding conditions. Determina-
tion of a Giardia genotype in the present investigation
was important, as genotypes A and B are found in hu-
mans. Because the genotype found in nine samples was
A1, whereas only one sample contained A2, and the fact
that these samples were all collected from puppies living
in different kennels, we can assume that we are facing a
potential zoonotic problem in communities that house
dogs taken from kennels [15].
The presence of several parasites (such as Giardia,
Cystoisospora and Toxocara) that were observed in the
present study have been studied and published by others
[4,5,16,17]. This multiple parasitism could be the result
of puppies becoming contaminated by their mother when
they were very small or contracted from living in small,
private spaces and/or lack of treatment due to the cost of
preventive medication. In addition, Nikolić [18] reported
that even inside private homes, there is a distinct preva-
lence of puppies with intestinal parasites. However, less
than 50% of the animals we tested showed positive re-
sults for infection.
Toxocara canis infection is both an animal and a hu-
man health problem that has been described in the last
decade, since it became possible to isolate Toxocara
from dog’s hair, public parks, gardens, and even indoor
homes [17,19,20]. Furthermore, it is an important zoo-
notic problem [21-23]. In humans, the disease is referred
as larva migrans, and it is considered an epidemiological
disease [24].
This investigation demonstrates the importance of
treating parasites in dogs, and recommends community
programs be offered on pet handling and immunization
E. Jiménez-Cardoso et al. / HEALTH 2 (2010) 1316-1319
Copyright © 2010 SciRes. http://www.scirp.org/journal/HEALTH/
Openly accessible at
to prevent further human infection, as some of the para-
sites have been isolated from both animals and humans,
suggesting a problem stemming from veterinary-human
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