Wild raccoon dogs (Nyctereutes procyonoides koreensis) may play a role transmitting several pathogens to humans and pet animals. Information concerning the incidence of rabies, canine distemper virus (CDV), canine parvovirus (CPV), canine adenovirus type 2 (CAdV-2), canine parainfluenza virus type 5 (CPIV-5), and canine herpesvirus (CHV) is needed in wild raccoon dogs. In total, 62 brain samples of raccoon dogs were examined for rabies virus (RABV) and CDV, and 49 lung samples were screened for CDV, CAdV-2, CPIV-5, and CHV. No RABV, CAdV-2, CPIV-5, or CHV was identified, but nine CDV antigens (8.1%, 9/111) were detected. Moreover, 174 serum samples from wild raccoon dogs were screened for antibodies against the five major viral pathogens. The overall serosurveillance against CDV, CPV, CAdV-2, CPIV-5, and CHV in wild raccoon dogs was 60.3%, 52.9%, 59.8%, 23.6%, and 10.3%, respectively. Comparisons of the sero-surveillance of the five pathogens showed that raccoon dogs of Gyeonggi province have slightly higher sero-positive rates against CDV, CPV, and CHV than those of Gangwon province. These results indicate high incidences of CDV, CPV, and CAdV-2 in wild raccoon dogs of two Korean provinces and a latent risk of pathogen transmission to companion and domestic animals.

Development of environmental, safe and protective vaccines against infectious pathogens remains a challenge. In consequence of its high morbidity and mortality rates canine distemper is one of the most important diseases of young dogs. The object of the present study is to develop a selected method for preparation of an inactivated canine distemper vaccine. This method involved exposure of the virus to different concentrations of binary ethyleneimine (BEI), beta propiolactone (ßPL) and hydrogen peroxide (H2O2). Complete virus inactivation was obtained with BEI (0.003M) for 6 hours, ßPL (1/5000) for 4 hours and H2O2 at a concentration of 3% rapidly inactivated a Vero cell adapted canine distemper virus strain within 3 h of exposure without affecting its antigenicity or immunogenicity. The safety, immunogenicity and potency induced in four groups of puppies were evaluated using the three prepared experimental batches of inactivated canine distemper vaccine. These results revealed that no residual infectious virus was detected in H2O2 inactivated CD vaccine that proved to be safe and effective when compared with the same virus harvest that inactivated with the classical inactivating agents as BEI and βPL. Thus, an alternative inactivation method, such as H2O2 is able to maintain the integrity of the virus protein may be essential for improving the potency of inactivated canine distemper virus vaccine produced sufficient of antibodies which measured by serum neutralization test (SNT) and was protected when challenged with virulent CD virus strain. These findings reinforce the idea that H2O2 can replace BEI and βPL as inactivating agents for canine distemper virus to reduce time and cost of inactivation process.

Canine distemper is a highly contagious disease with high incidence and lethality in the canine population. The objective of this study was to evaluate the efficacy of antiviral action with ribavirin (RBV), interferon-alpha (IFNa), and combinations of RBV and IFN a against canine distemper virus (CDV). Vero cells inoculated with CDV were treated with RBV, IFNa, and combinations of these drugs. The efficacy to inhibit viral replication was evaluated by adding the compounds at different times to determine which step of the viral replicative process was affected. Both drugs were effective against CDV in vitro. The IFNa was the most active compound, with an average IC50 (50% inhibitory concentration) value lower than the IC50 of the RBV. Ribavirin (RBV) was more selective than IFN a, however, and neither drug showed extracellular antiviral activity. The combination of RBV and IFN a exhibited antiviral activity for the intra- and extracellular stages of the replicative cycle of CDV, although the intracellular viral inhibition was higher. Both RBV and IFN a showed high antiviral efficacy against CDV, and furthermore, RBV 1 IFNa combinations have shown greater interference range in viral infectivity. These compounds could potentially be used to treat clinical disease associated with CDV infection.

A penta-dog inactivated cell culture vaccine was prepared to protect dogs against canine distemper virus, canine parvovirus, canine adenovirus1, 2 and rabies virus. The potency of this vaccine was compared with that of single inactivated vaccines prepared against each disease, in different groups of susceptible dogs. It was found that the protective dose of penta-dog vaccine (2ml) including the protective amounts of the five viral proteins resulted in full protection of vaccinated dogs against the challenge with virulent strain of the used viruses showing no antagonizing effect between each other with and no adverse postvaccinal reaction. So, the prepared inactivated cell culture penta-dog vaccine is a safe and potent vaccine for dogs which resulted in saving time, cost, and effort stress factors on animals and providing good immune statues.

The diagnostic value of RT-PCR and hemi-nested RT-PCR (hnRT-PCR) was compared in brain samples of dogs presenting neurological signs compatible with canine distemper. Samples of central nervous system (CNS) were collected from 68 dogs and tested by direct immunofluorescence test (RFID) and, independent of the results, they were stored at -20°C for at least three years. They were submitted to the RT-PCR and hnRT-PCR techniques aiming to determine the gene responsible for the viral nucleoprotein decoding. Fifty-nine samples were positive for RIFD, 40 for RT-PCR (Kappa = 0.358) and 54 for hnRT-PCR (Kappa = 0.740). All nine RIFD negative samples were also negative for RT-PCR and hnRT-PCR. In spite of the storage duration and proper sample conditions, the estimated accordance between hnRT-PCR and RIFD demonstrated that hnRT-PCR technique can be applied in retrospective studies.