Vaccination with canine parvovirus type 2 (CPV-2) protects against challenge with virulent CPV-2b and CPV-2c.

Mutations in canine parvovirus (CPV) field isolates have created concerns regarding the ability of vaccines containing CPV-2 to protect against infection with the newly identified antigenic types CPV-2b and CPV-2c. To address this concern, the efficacy of CPV-2 strain NL-35-D currently in use as a commercial vaccine was demonstrated against an oral challenge with CPV-2b and CPV-2c, respectively. Clinically healthy specific pathogen free Beagle dogs were either vaccinated or treated with water for injection first at 8-9 weeks of age and again at 11-12 weeks of age. All dogs were challenged either with CPV-2b or CPV-2c three weeks after the second vaccination. During the two week period following challenge, clinical signs, white blood cell counts, serology by haemagglutination inhibition (HI) and serum neutralisation tests, and virus shedding by haemagglutination test were assessed. All control dogs developed clinical signs of parvovirosis (including pyrexia and leucopenia) and shed virus. Vaccinated dogs seroconverted (HI titres > or =80), remained healthy throughout the study and shed more than 100 times less virus than controls. In conclusion, vaccination with the low passage, high titre CPV-2 strain NL-35-D cross-protects dogs against virulent challenges with CPV-2b or CPV-2c by preventing disease and substantially reducing viral shedding.

Feasibility of genus-specific real-time PCR for the differentiation of larvae from gastrointestinal nematodes of naturally infected sheep.

Results of real-time PCR analysis of coproculture third stage larvae (L3) using genus specific TaqMan minor groove binder probes were compared with the results of morphological differentiation of L3 after coprocultured and direct morphological worm differentiation from gastrointestinal samples of eight sheep with naturally acquired nematodes infections. Faecal egg counts prior to postmortem confirmed infections with trichostrongyles with a geometric mean count of 4828 eggs per gram for all sheep. Individual egg counts correlated positively with total worm counts (correlation coefficient 0.794). Five different nematode species and one genus were found in the abomasi and small intestines: Cooperia curticei, Haemonchus contortus, Nematodirus spp., Teladorsagia (Ostertagia) circumcincta, Trichostrongylus axei and Trichostrongylus colubriformis. Coproculture of faecal eggs yielded five of these, Cooperia spp., Haemonchus spp., Ostertagia/Teladorsagia spp. and Trichostrongylus spp. Comparison between morphological L3 and worm differentiation data showed high congruence (94%). The agreement between PCR analysis of L3 after coproculture and direct morphological worm differentiation was 84%. Thus, real-time PCR was found to be suitable as a speedy and reliable diagnostic tool for the assessment of gastrointestinal nematode infections of ruminants in the field.