BackgroundCanid herpesvirus-1 (CaHV-1) infection in puppies less than three weeks of age is often reported to be associated with a lethal generalized necrotizing inflammation and since the discovery of the virus in 1965 several reports of neonatal infections have been published. However, the significance of CaHV-1 for peri- and neonatal mortality in puppies remains unclear. Therefore, we examined stillborn and dead neonatal puppies in Denmark to determine the prevalence of infection and further to correlate infection levels with necropsy findings to assess the possible significance of the infection.ResultsFrom a cross-sectional study of 57 dead puppies, 22.8% (n = 13) were confirmed positive for CaHV-1 by real-time polymerase chain reaction (PCR) of tissue pools of lung/liver and/or spleen/kidney. Specimens from PCR positive cases were further investigated by histology and in situ hybridization (ISH). High levels of CaHV-1 DNA were present in only one case in which lesions and ISH staining consistent with CaHV-1 infection were found as well. CaHV-1 concentrations in the other cases were low and a range of lesions not consistent with CaHV-1 were found. Similar, ISH staining was mostly negative in these except for one case with a few positive cells.ConclusionCaHV-1 infection in stillborn and dead neonatal puppies in Denmark seems to be common, but the direct significance for puppy mortality remains unclear as only one of 13 PCR positive puppies (7.7%) had pathognomonic lesions.Electronic supplementary materialThe online version of this article (doi:10.1186/s13028-014-0092-9) contains supplementary material, which is available to authorized users.

Objectives The amino acid substitutions M1058L and S1060A in the spike protein of feline coronavirus (FCoV) have been postulated to be responsible for the development of the pathogenic feline infectious peritonitis virus (FIPV), which causes feline infectious peritonitis (FIP). The aim of the following study was to investigate the presence of mutated virus in tissue samples of cats with and without FIP. Methods The study population consisted of 64 cats, 34 of which were diagnosed with FIP and 30 control cats. All cases underwent autopsy, histopathology and immunohistochemistry (IHC) for FCoV. Furthermore, a genotype-discriminating quantitative reverse transcriptase PCR (RT-qPCR) was performed on shavings of paraffin-embedded tissues to discriminate between cats with FIP and controls, and the sensitivity and specificity of this discriminating RT-qPCR were calculated using 95% confidence intervals (CIs). Results Specificity of genotype-discriminating RT-qPCR was 100.0% (95% CI 88.4-100.0), sensitivity was 70.6% (95% CI 52.5-84.9). In cats with FIP, 24/34 cats tested positive for FIPV. In samples of three control cats and in seven cats with FIP, FCoV was found, but genotyping was not possible owing to low FCoV RNA concentrations. Out of the positive samples, 23 showed the amino acid substitution M1058L in the spike protein and none the substitution S1060A. One sample in a cat with FIP revealed a mixed population of non-mutated FCoV and FIPV (mixed genotype). For one sample genotyping was not possible despite high viral load, and two samples were negative for FCoV. Conclusions and relevance As none of the control animals showed FCoV amino acid substitutions previously demonstrated in cats with FIP, it can be presumed that the substitution M1058L correlates with the presence of FIP. FCoV was detected in low concentration in tissues of control animals, confirming the ability of FCoV to spread systemically. The fact that no negative controls were included in the IHC protocol could potentially lead to an underestimation of the sensitivity of the RT-qPCR.