| dc.description.abstract | Parasitic infections remain the most important infections affecting companion animals worldwide,
and pose a great risk to animal and human health. Information on these infections in dogs in Ghana
and the management practices for the dogs including anthelmintics used and their effectiveness is
scanty. The objectives of this study were to (i) determine the occurrence and prevalence of
gastrointestinal helminth, ectoparasites and haemoparasites in dogs in the Greater Accra Region
(GAR) of Ghana and the management practices of dogs, (ii) determine the efficacy of
anthelmintics commonly used for dogs in GAR (iii) document clinical and pathological
manifestations of hookworm and ascarid infections in dogs and (iv) validate effectiveness of a
Toxocara canis IgG ELISA in the detection of ascarid infections in dogs.
To determine the prevalence of helminth and hemoparasite infections, faecal and blood samples
were obtained from 392 dogs in the GAR. The faecal samples were examined using the modified
McMaster technique. Blood smears were examined for hemoparasites by microscopy.
Management practices for the dogs were assessed through questionnaires administered to the dog
owners (204), veterinarians (18) and veterinary drug store attendants (32). Overall, prevalence of
gastrointestinal helminths was 62.6% (n=380). Hookworm eggs were found in 178 (48.6%) dogs,
Toxocara canis eggs in 22 (5.7%) and mixed infections of hookworms and T. canis in 38 (10%).
Dipylidium caninum was the adult tapeworm found in (51; 13.4%) dogs aged 12 months and above.
In comparing the management practices with the prevalence using the multivariate analysis
revealed that high prevalence of helminth infection was found mainly in dogs bought from street
vendors (84%; P=O.OOl), not housed (70%; P=O.OOI) and kept for hunting (86.4%; P=O.OOO1) and
security (47.2; P=O.OOI) purposes. Blood samples showed Ehrlichia canis in 15 (4.03%), Babesia
canis in 7 (1.8%) and Trypanosoma spp in 2 (0.5%) dogs. Twenty nine (7.4%) dogs had cutaneous
myiasis caused by Cordylobia rodhaini, one (0.2%) of which also had intestinal myiasis caused
by Dermatobia hominis. Seventy eight (38.2%) ofthe dogs owners were educated up to the tertiary
level, a few (13; 6.3%) knew the zoonotic risk associated with dog keeping.
Controlled anthelmintic efficacy tests based on the percentage reduction in fecal egg count (FECR
%) and total worm count (WCR %) were carried out for three anthelmintic combinations and
ivermectin (IV) in the treatment of ascarids and hookworms. The tests were carried out on naturally
infected dogs in Kenya. The three anthelmintic drug combinations tested were ALBEN (50mg
albendazole + 5mg praziquantel per kg of bodyweight [kg/bw]), NL (50rhg niclosamide + 4mg
levamisole per kg/bw), PRA (5mg praziquantel+ 14.4mg pyrantel pamoate + 15mg febantel). Each
combination drug and IV was administered as per the manufacturer's instructions to six naturally
infected puppies, aged 6 to 8 weeks. A control group of 6 untreated puppies was included. Two
additional groups of six puppies each, were added during the experiment, to ascertain some lesions
that were observed in the ALBEN treated puppies. The 2 groups were a negative control
(uninfected control) and uninfected but treated with ALBEN (negative control treated). All puppies
were sampled prior to treatment and on daily basis from day 0 to 6 post treatment. They were
euthanized on day 7 for post mortem and, histopathological examination of the intestines.
The FECR % for ALBEN, PRA and NL against Toxocara canis were 100% while that for IV was
99%. For hookworm, NL, PRA and IV achieved 100% efficacy butALBEN had a lower efficacy
of59.3%. Higher efficacy of up to 100% is required for parasites of public health importance. The
WCR% for ALBEN, PRA, NL and IV against T. canis was 97%, 99%, 100% and 74%,
respectively. For hookworm, the efficacies for NL, PRA, IV and ALBEN were 100%,97%, 100%
and 66.2%, respectively. Postmortem examination of the puppies revealed a thickened and
corrugated mucosa of the intestines in 83% (10/12) of the ALBEN treated dogs unlike in the
untreated controls (P<0.05) dogs. Histopathology showed thickening of the mucosa, submucosa
and muscularis of the intestines in 83% of the ALBEN treated dogs.
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The development of clinical signs accompanying hematologic, coproscopic and pathological
findings of hookworm and Toxocara infection was studied in dogs. The effectiveness of T canis
IgG ELISA to detect ascarid infections in dogs was also tested. Twelve parasite-free puppies, aged
4 weeks, were randomly allocated to 2 groups. One group was infected with 200 embryonated T
canis eggs administered orally, while the other group remained uninfected. The infections were
followed for 8 weeks post infection (p.i). Twelve other puppies aged between 5 and 6 weeks were
also allocated into hookworm infected and un infected controls. The infected group was given 200
third stage hookworm larvae percutaneously. They were followed up for 7 weeks p.i. Weekly
faecal and hematological parameters were performed on each group for the whole experimental
period. Serum was obtained from the T canis infected dogs weekly for the ELISA tests. All dogs
were euthanized on week 7 and 8 for hookworm and T canis respectively, for necropsy and
histopathological examinations.
Prepatent periods for T canis and hookworm were 28 and 14 days respectively. Clinical signs and
hematologic results for the 6 Toxocara infected dogs included weight loss (66.6%), dullness
(100%), lymphocytosis (83.3%) and eosinophilia with mass degranulation (66.6%).
Histopathological lesions included destruction of villi (100%), marked increase in infiltration of
eosinophils, lymphocytes and plasma cells in the lamina propria and submuscosa of the intestines.
The IgG ELISA failed to detect infection in T canis infected dogs. Clinical signs and hematologic
results seen in hookworm infected dogs included weight loss (83.3%) and persistent piloerection
(of the backline fur) in 5 out of 6 dogs in week 4 to 7 pi. Others were eosinophilia (83.3%) and
lymphocytosis in 5/6. Gross pathological lesions included red spots and tracks in the diaphragmatic
lobes of the lungs in 3 out of 6 infected, ecchymotic hemorrhages in the small intestines in all the
dogs. Destruction of the villi (100%) and oedema of the mucosa in 50% was observed at
histopathology.
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In conclusion, hookworms, Toxocara species and Dipylidium caninum were the gastrointestinal
helminths prevalent in dogs in the GAR of Ghana. Very few dog owners knew the zoonotic risk
associated with dog keeping. Larvae of the flies Cordylobia rodhaini and Dermatobia hominis
were found to cause myiasis in owned dogs. This is the first report describing myiasis in animals
in Ghana. ALBEN was not effective against hookworm and was found to be significantly
associated with an inflammation of the mucosa ofthe intestines in dogs. This has not been reported
previously in dogs. The PRA and NL were effective against hookworm and T. canis. Although
previously described in the diagnosis of ascarid infections in humans, the Toxocara canis IgG
ELISA did not detect Toxocara antibodies in the serum of infected dogs. Eosinophilia, mass
degranulation of eosinophils and weight loss were common features indicative of hookworm and
Toxocara infections in dogs. | en_US |
