Validation of molecular diagnostics for the detection of pseudocowpox virus

The pseudocowpox virus (PCPV) is recognized for causing exanthematic lesions in cattle and humans. The diagnosis is important because it is a zoonosis and its clinical signs can be confused with foot-and-mouth disease, a high-impact bovine disease in livestock. The objective of this work is to validate a SYBR Green qPCR and a conventional PCR for virus detection in bovine samples. Detection limit tests, repeatability, reproducibility, sensitivity, and specificity were compared. When two analysts were compared, results demonstrated that training and pipetting influence the repeatability. The qPCR was more sensitive than conventional PCR but showed nonspecific reactions distinguishable by the melting curve. Both showed high repeatability and reproducibility.

First molecular characterization of poxviruses in cattle, sheep, and goats in Botswana

Background

Poxviruses within the Capripoxvirus, Orthopoxvirus, and Parapoxvirus genera can infect livestock, with the two former having zoonotic importance. In addition, they induce similar clinical symptoms in common host species, creating a challenge for diagnosis. Although endemic in the country, poxvirus infections of small ruminants and cattle have received little attention in Botswana, with no prior use of molecular tools to diagnose and characterize the pathogens.

Methods

A high-resolution melting (HRM) assay was used to detect and differentiate poxviruses in skin biopsy and skin scab samples from four cattle, one sheep, and one goat. Molecular characterization of capripoxviruses and parapoxviruses was undertaken by sequence analysis of RPO30 and GPCR genes.

Results

The HRM assay revealed lumpy skin disease virus (LSDV) in three cattle samples, pseudocowpox virus (PCPV) in one cattle sample, and orf virus (ORFV) in one goat and one sheep sample. The phylogenetic analyses, based on the RPO30 and GPCR multiple sequence alignments showed that the LSDV sequences of Botswana were similar to common LSDV field isolates encountered in Africa, Asia, and Europe. The Botswana PCPV presented unique features and clustered between camel and cattle PCPV isolates. The Botswana ORFV sequence isolated from goat differed from the ORFV sequence isolated from sheep.

Conclusions

This study is the first report on the genetic characterization of poxvirus diseases circulating in cattle, goats, and sheep in Botswana. It shows the importance of molecular methods to differentially diagnose poxvirus diseases of ruminants.

First detection and molecular characterisation of pseudocowpox virus in a cattle herd in Zambia

Background

Pseudocowpox virus (PCPV) of the genus Parapoxvirus in the family Poxviridae causes pseudocowpox in cattle worldwide and presents a zoonotic concern. Most poxviruses produce diseases of similar clinical signs in affected animals, which are impossible to differentiate clinically or by serology. It is, therefore, vital to use molecular assays to rapidly identify the causative agents of poxvirus infections. This study aimed to detect, diagnose, and characterize the causative agent of pox-like skin lesions in a cattle herd in Zambia, initially suspected to be infected with Lumpy Skin Disease virus.

Methods

We used a High-Resolution Melting (HRM) analysis assay to detect the PCPV genome and sequenced the major envelope protein (B2L gene) for comparative sequence and phylogenetic analysis.

Results

Our field investigations showed cattle presenting atypical skin lesions and high morbidity within the herd. The laboratory diagnosis, based on the HRM assay revealed PCPV DNA in the samples. Phylogenetic and comparative sequence analyses confirmed PCPV in the samples and revealed genomic differences between samples collected in 2017 and 2018 from the same farm.

Conclusion

Our work is the first documented report of PCPV in Zambia. It shows the strength of molecular methods to diagnose pox-like infections in cattle and discriminate between diseases causing similar clinical signs. This rapid and accurate diagnosis improves the response time for more accurate veterinary interventions.

Pseudocowpox virus infection in an American bison (Bison bison)

Background

The present report describes a case of pseudocowpox virus (PCPV) infection in a seven-year-old female bison euthanized due to a history of declining condition and sores on the vulva and udder.

Case presentation

External examination revealed multifocal, raised, keratinized plaques (0.5–2 cm) covering the skin of the ventral surface of the tail, perineum, caudoventral abdomen, udder, both inguinal recesses, and the medial aspects of both thighs. No significant gross lesions were present in the reminder of the tissues examined. Histopathological examination of the affected skin showed moderate epidermal hyperplasia with rete pegs, marked parakeratotic hyperkeratosis with crusts of degenerate neutrophils and cell debris, and few epithelial cells undergoing ballooning degeneration with occasional eosinophilic intracytoplasmic inclusion bodies (3–5 μm Bollinger body). Negative staining electron microscopy from skin revealed typical Parapoxvirus (PPV) particles, which were also confirmed by real-time PCR (Ct =18.6). Metagenomic analysis of the skin samples revealed only poxviruses. The bison parapox B2L envelope gene clustered with other parapox sequences identified from ruminants.

Conclusions

This is the first report of PCPV virus infection in an American bison. Identification of novel susceptible hosts of parapox viruses sheds light on the viral evolution and highlights the importance of potential economic impact of this disease to the bison industry.

First isolation and genetic characterization of pseudocowpox virus from cattle in Japan

Background

Pseudocowpox virus (PCPV) infects cattle worldwide with zoonotic potential but has not been isolated in Japan. Thus, the epidemiological status of PCPV infection in cattle is undetermined.

Results

In May 2016, a cattle in a farm in Yamaguchi Prefecture showed white vesicles and hyperemia in the mucosa under the tongue surface, but not on the teats and coronary cushions. A parapoxvirus was isolated from the oral lesion swab and was genetically characterized based on the full-length sequence of B2L gene encoding viral envelope. Phylogenetic analysis showed that the isolated virus was classified into PCPV.

Conclusion

This case indicates its potential spread in Japan. This is the first report of isolation of PCPV in Japan.

Electronic supplementary material

The online version of this article (10.1186/s12985-017-0840-3) contains supplementary material, which is available to authorized users.

Evidence of zoonotic pseudocowpox virus infection from a cattle in Turkey

Pseudocowpox virus (PCPV) infects cattle throughout the world and has zoonotic potential. However, it is not known to infect cattle in Turkey. In August 2013, we observed ulcerative nodular swelling and pustules on udder and teats of a cow in a small village nearly Lake of Bafa, Milas, Mugla locate in southwestern part of Turkey. Interestingly, the similar lesions were also observed on skin of milkier women's hand at the same time. A PCPV strain was characterized based on the major envelop gene sequence. The phylogenetic analysis showed that the isolated strain was closely related to the members of other parapoxvirus genus. This study provides the first description of PCPV infection in Turkey.

Phylogenetic analysis and positive-selection site detecting of vascular endothelial growth factor family in vertebrates

Vascular endothelial growth factor (VEGF), known to play an important role in vascular homeostasis, vascular integrity and angiogenesis, is little known about the evolutionary relationship of its five members especially the role of gene duplication and natural selection in the evolution of the VEGF family. In this study, seventy-five full-length cDNA sequences from 33 vertebrate species were extracted from the NCBI's GenBank, UniProt protein database and the Ensembl database. By phylogenetic analyses, we investigated the origin, conservation, and evolution of the VEGFs. Five VEGF family members in vertebrates might be formed by gene duplication. The inferred evolutionary transitions that separate members which belong to different gene clusters correlated with changes in functional properties. Selection analysis and protein structure analysis were combined to explain the relationship of the site-specific evolution in the vertebrate VEGF family. Eleven positive selection sites, one transmembrane region and the active sites were detected in this process.