Abstract:
Gastroenteritis is a frequent presentation in canine practice with challenges in its diagnosis and
management. Canine Parvovirus (CPV) is a common cause of gastroenteritis, mortality, and
economic losses with recurrent vaccination failure. Due to limited documented information on the
condition in Nigeria, this study was designed to investigate the prevalence, aetiologies, clinical
presentation, and management of canine gastroenteritis, and characterise CPV isolates in Nigeria.
Retrospective data of 3,882 dogs presented to ten veterinary clinics from seven locations
(Abeokuta, Abuja, Ibadan, Jos, Makurdi, Onitsha and Warri) in Nigeria from January to December
2016 were analysed for prevalence and drug prescription patterns for gastroenteritis. Also, 157
cases of gastroenteritis were prospectively evaluated for their aetiologies and usefulness of clinical
pathology in prognostication using standard procedures. Electrocardiograms of 40 dogs with
confirmed Canine Parvovirus Enteritis (CPE) using rapid in-clinic assay kit and polymerase chain
reaction were evaluated for cardiac involvements. Protocols of CPV vaccination failure (94/157)
were examined for appropriateness. Polymerase chain reaction was done on the vaccine and
positive clinical samples using primers specific for parvoviral DNA and subjected to sequencing
and phylogenetic analysis. Data were analysed using descriptive statistics, Chi-square, and logistic
regression at α0.05.
Prevalence of gastroenteritis was 41.2% and was influenced by dog breed (α=0.014), vaccination
status (α=0.047) and period of the year (α=0.03). Polypharmacy was high with an average of 5.4
drugs prescribed in each treatment regimen. Antibacterials (48.3%) and antiparasitics (23.8%)
were extensively prescribed. Canine parvovirus (92.9%), gastrointestinal parasites (12.1%),
coronavirus (2.6%), liver disease (0.6%) and undetermined causes (1.9%) were identified as the
aetiologies of the clinical cases. Colic (Odds Ratios [OR]=0.01; α=0.001), leukopaenia (OR=3.5,
α=0.01), hypoalbuminaemia (OR=7.1; α=0.006) and pancytopaenia (OR=0.2; α=0.002) at initial
time of presentation were prognostic for prolonged duration of management and poor outcomes.
Electrocardiographic changes comprising ST-depression (7.5%), tall T-wave (27.5%), S-wave
deepening (20.0%), prolonged QT-duration (25.0%), prolonged P-wave duration (17.5%), and
tachycardia (15.0%) were seen in 70.0% of confirmed CPE cases. Vaccination failure was
associated with the protocol adopted, with one-, two-, three- and four-dose protocols having failure
rates of 51.1%, 28.7%, 19.1% and 1.1%, respectively. Sequence and phylogenetic analysis of 11
clinical samples showed that CPV-2c (63.6%) and CPV-2a (36.4%) were the predominant strains
and were genetically closely related to Asian and European strains. Amino acid changes (T301S,
D305Y, Y323I, Q370R, T440A, Y444S and I447M) were observed in the VP2 protein of the
clinical isolates. The vaccines that were sequenced contained CPV-2a only.
Canine parvovirus and gastrointestinal parasites were the leading causes of canine gastroenteritis
in Nigeria. Prescription patterns used in managing several cases were injudicious. Presentation
with colic, hypoalbuminaemia and leukopaenia are useful indicators for poor prognosis and
prolonged management. Assessment of cardiac functions in canine parvovirus enteritis is
recommended. Inappropriate vaccination protocols, viral mutations, and incorporation of only
CPV-2a strain in vaccines licensed for vaccinating dogs against canine parvovirus portends risk of
vaccination failure.
