Genetic diversity of canine parvovirus variants circulating in Nigeria

Canine parvovirus (CPV) is a fast-evolving single-stranded DNA virus that causes severe and fatal gastrointestinal disease in dogs. Lately, several mutations affecting viral protein (VP) capsid resulting in highly pathogenic variants with distinctive immunological and clinicopathological characteristics abound. This study involved screening stools of 44 randomly selected clinical cases of canine gastroenteritis from 4 cities (Ibadan, Jos, Makurdi, and Zaria) in Nigeria for CPV antigen using an on-the-spot immunoassay test kit, as well as, molecular detection of viral nucleic acid by polymerase chain reaction. Subsequently, nucleic acid sequencing of 1195-bp amplicons encompassing the VP2 encoding region was done. The resultant 40 high-quality amino acid sequences obtained were analysed for the identification and grouping of the viruses into their discrete variants - CPV-2a, CPV-2b, or CPV-2c, using key amino acids substitutions - Asn, Asp, or Glu respectively at position 426 of the VP2 gene. One-third (11/40; 27.5%) of the analysed sequences were identified as CPV-2a and two-third (29/40; 72.5%) as CPV-2c. The original CPV and CPV-2b were not detected. Also, the "new CPV-2a variant" with mutation S297A identified had two additional mutations (Y324I and T440A) associated with selective pressure and vaccination failure in their sequences. Similarly, unique CPV-2c mutants carrying genetic markers (S297A, Y324I, and Q370R) that are highly related to CPVs of Asian origin were observed. These findings revealed a high level of divergence of existing CPVs in circulation; suggesting that CPV is rapidly evolving in Nigeria lately.

Long-term effects of canine parvovirus infection in dogs

BACKGROUND

Canine parvovirus (CPV) is the most important viral cause of acute canine enteritis leading to severe damage of the intestinal barrier. It has been speculated that dogs might develop chronic disorders after surviving CPV infection. However, no studies regarding the long-term implications of CPV infection have been published to date. The aim of this study was to evaluate whether dogs that have survived CPV infection will have an increased risk for developing chronic gastroenteritis, atopic dermatitis, or cardiac disease.

METHODOLOGY/PRINCIPAL FINDINGS

Dogs that had been treated at the Clinic of Small Animal Medicine, LMU Munich, for CPV infection for which a follow-up of at least 12 months was available, were included in the study. Owners completed a questionnaire on the presence of chronic gastrointestinal and cutaneous signs, cardiac disease, and other potential disorders. An identical questionnaire was sent to owners of matched control dogs during the same time period. Seventy-one questionnaires of dogs with CPV infection and 67 of control dogs were analyzed. Significantly more CPV-infected dogs (30/71) compared to control dogs (8/67) had developed chronic gastrointestinal signs later in their lives (P < 0.001). No significant differences were observed regarding skin diseases (P = 1), cardiac problems (P = 0.160), or any other diseases (P = 0.173) later in life.

CONCLUSIONS

Results of this study suggest that dogs that survive CPV infection have a significantly higher risk (odds ratio = 5.33) for developing a chronic gastrointestinal disease. Further prospective studies to identify the trigger for the development of chronic diarrhoea and possible targeted treatment strategies are needed.