Canine parvovirus and pseudorabies virus coinfection as a cause of death in a wolf (Canis lupus) from southern Italy

Survey on the Occurrence of Zoonotic Bacterial Pathogens in the Feces of Wolves (Canis lupus italicus) Collected in a Protected Area in Central Italy

Previous investigations have explored the involvement of wolves in parasitic and viral diseases, but data on the zoonotic bacteria are limited. The aim of this study was to assess the occurrence of bacterial zoonotic agents in 16 wolf (Canis lupus italicus) fecal samples collected in a protected area in Central Italy. Campylobacter spp., Salmonella spp., Yersinia spp., Listeria monocytogenes, and Shiga Toxin-Producing Escherichia coli (STEC) were investigated by culture, while polymerase chain reaction (PCR) was employed to detect Coxiella burnetii, Mycobacterium spp., Brucella spp., and Francisella tularensis. The presence of Extended Spectrum β-Lactamase (ESBL)- and carbapenemase-producing Enterobacteriaceae was also evaluated, using selective isolation media and detection of antimicrobial resistance genes. All samples were negative for Campylobacter spp., Salmonella spp., C. burnetii, Mycobacterium spp., Brucella spp., F. tularensis, and carbapenemase-producing Enterobacteriaceae. One sample tested positive for Yersinia aldovae and three for Yersinia enterocolitica BT1A. One L. monocytogenes (serogroup IIa) and one STEC, carrying the stx1 gene, were isolated. Two ESBL isolates were detected: one Serratia fonticola, carrying blaFONA-3/6 gene, and one Escherichia coli, carrying blaCTX-M-1 gene. Both ESBL isolates were resistant to different antimicrobials and therefore classified as multi-drug-resistant. Our data suggest that wolves are potential carriers of zoonotic bacteria and may contribute to the environmental contamination through their feces.

The host cells suppress the proliferation of pseudorabies virus by regulating the PI3K/Akt/mTOR pathway

Pseudorabies virus (PRV), a member of the alpha-herpesviruses, can infect both the nervous and reproductive systems of pigs, causing neonatal mortality and reproductive failure in sows, which incurs substantial economic losses. Neurotropism is a common characteristic of various viruses, allowing them to cross the blood-brain barrier and access the central nervous system. However, the precise mechanisms by which PRV affects the blood-brain barrier are not well understood. To investigate the mechanism of PRV's interaction with the blood-brain barrier and its engagement with the PI3K/Akt signaling pathway during infection, an in vitro monolayer cell model of the blood-brain barrier was established. Our research found that PRV activates Matrix metallopeptidase 2 (MMP2), which degrades Zonula occludens-1 (ZO-1) and consequently enhances the permeability of the blood-brain barrier. PRV infection elevated the transcriptional levels of tissue inhibitor of metalloproteinases 1 (TIMP1) and inhibited its degradation through the ubiquitin-proteasome pathway, leading to higher intracellular concentrations of TIMP1 protein. TIMP1 regulates apoptosis and inhibits PRV replication in mouse brain microvascular endothelial cells through the PI3K/Akt/mTOR signaling pathway. In summary, our study delineates the mechanism through which PRV compromises the blood-brain barrier and provides insights into the host's antiviral defense mechanisms post-infection.

IMPORTANCE

PRV, known for its neurotropic properties, is capable of inducing severe neuronal damage. Our study discovered that following PRV infection, the expression of MMP2 was upregulated, leading to the degradation of ZO-1. Furthermore, upon PRV infection in the host, the promoter of TIMP1 is significantly activated, resulting in a significant increase in TIMP1 protein levels. This upregulation of TIMP1 inhibits the proliferation of PRV through the PI3K/Akt signaling pathway. This study elucidated the mechanism through which PRV, including the PRV XJ delgE/gI/TK strains, compromises the blood-brain barrier and identifies the antiviral response characterized by the activation of the PI3K/Akt signaling pathway within infected host cells. These findings provide potential therapeutic targets for the clinical management and treatment of PRV.

A pseudorabies outbreak in hunting dogs in Campania region (Italy): a case presentation and epidemiological survey

BACKGROUND

Pseudorabies is an infection of domestic and wild pigs that has occasionally been reported in dogs with fatal encephalitis. Hunting dogs are predisposed to pseudorabies exposure due to incorrect practices (administration of raw infected meat) or close contact with infected wild boars. This study described an outbreak of pseudorabies in two hunting dogs in the Campania region, southern Italy.

CASE PRESENTATION

Two hunting dogs were hospitalized after a hunting trip, with fever, itching, and self-inflicted lesions. Laboratory tests showed mild anemia and marked leukocytosis. Despite conservative therapy, both animals died 48 h after the presentation of symptoms. One of the carcasses was sent to the Department of Veterinary Medicine and Animal Production in Naples to confirm the suspicion of pseudorabies. DNA was extracted from different matrices and used as a template for real-time PCR to detect PRV. Several samples (brain, cerebellum, brainstem, lung, and liver) tested positive. Subsequent sequence analyses of glycoprotein E from DNA extracted from the brain stem revealed a sequence similarity to those described in previous cases of pseudorabies in dogs in Italy, France and Belgium. One month after the outbreak, blood samples were collected from 42 dogs belonging to the same hunting team and from 245 dogs (cohort population) living in the Campania region. All samples were tested with two commercial ELISAs to detect seroconversion against glycoproteins B and E. A seroprevalence of 19% was observed in the hunting team affected by the outbreak, while only 0.8% was observed in the regional dog population.

CONCLUSIONS

The data reported in this study demonstrate potential exposure to PRV by dead-end hosts, particularly hunting dogs. The sequencing results indicated the homogeneity of PRV strains circulating in the different Italian regions.

Detection and molecular analysis of Pseudorabies virus from free-ranging Italian wolves (Canis lupus italicus) in Italy - a case report

BACKGROUND

The only natural hosts of Pseudorabies virus (PRV) are members of the family Suidae (Sus scrofa scrofa). In mammals, the infection is usually fatal and typically causes serious neurologic disease. This study describes four Aujeszky's disease cases in free-ranging Italian wolves (Canis lupus italicus). In Italy, the wolf is a strictly protected species and is in demographic expansion.

CASE PRESENTATION

Three wolves (Wolf A, B, and C) were found in a regional park in Northern Italy, and one (Wolf D) was found in Central Italy. Wolf A and D were alive at the time of the finding and exhibited a fatal infection with epileptic seizures and dyspnoea, dying after a few hours. Wolf B presented scratching lesions under the chin and a detachment of the right earlobe, whilst Wolf C was partially eaten. The wolves showed hepatic congestion, diffuse enteritis, moderate pericardial effusion, severe bilateral pneumonia, and diffuse hyperaemia in the brain. The diagnostic examinations included virological analyses and detection of toxic molecules able to cause serious neurological signs. All four wolves tested positive for pseudorabies virus (PrV). The analysed sequences were placed in Italian clade 1, which is divided into two subclades, "a" and "b". The sequences of Wolf A, B, and C were closely related to other Italian sequences in the subclade b, originally obtained from wild boars and hunting dogs. The sequence from Wolf D was located within the same clade and was closely related to the French hunting dog sequences belonging to group 4.

CONCLUSION

Results showed the presence of PrV strains currently circulating in wild boars and free-ranging Italian wolves. The genetic characterisation of the PrV UL44 sequences from the four wolves confirmed the close relationship with the sequences from wild boars and hunting dogs. This fact supports a possible epidemiological link with the high PrV presence in wild boars and the possibility of infection in wolves through consumption of infected wild boar carcasses or indirect transmission. To the best of our knowledge, this study is the first detection of Pseudorabies virus in free-ranging Italian wolves in northern and central Italy.

Suid alphaherpesvirus 1 of wild boar origin as a recent source of Aujeszky's disease in carnivores in Germany

BACKGROUND

The high susceptibility of carnivores to Suid Alphaherpesvirus 1 [SuAHV1, synonymous pseudorabies virus (PrV)], renders them inadvertent sentinels for the possible occurrence of Aujeszky's disease (AD) in domestic and wild swine populations. The aim of this study was to epidemiologically analyse the occurrence of PrV infections in domestic and wild animals in Germany during the last three decades and to genetically characterise the causative PrV isolates.

METHODS

PrV in dogs was detected using standard virological techniques including conventional and real time PCR, virus isolation or by immunohistochemistry. Available PrV isolates were characterized by partial sequencing of the open gC reading frame and the genetic traits were compared with those of archived PrV isolates from carnivores and domestic pigs from Germany before the elimination of AD in the domestic pig population.

RESULTS

During 1995 and 2022, a total of 38 cases of AD in carnivores, e.g. dogs and red foxes, were laboratory confirmed. Sequencing and subsequent phylogenetic analysis of PrV isolates established a strong connection between AD cases in carnivores and the occurrence of PrV infections in European wild boars in the end phase of and after elimination of AD from the domestic pig population. While PrV infections occur at low numbers but regularly in hunting dogs, interestingly, PrV was not observed in grey wolves in Germany. In none of 682 dead-found grey wolves and wolf-dog hybrids tested from Germany during 2006-2022 could PrV infection be detected by molecular means.

CONCLUSIONS

Although PrV has been eliminated from domestic pigs, spillover infections in domestic and wild carnivores should always be expected given the endemic presence of PrV in wild pig populations. Since detection of PrV DNA and virus in carnivores is sporadic even in areas with high seroprevalence of PrV in wild pigs, it may not reflect the full diversity of PrV.

A Review of Pseudorabies Virus Variants: Genomics, Vaccination, Transmission, and Zoonotic Potential

Pseudorabies virus (PRV), the causative agent of Aujeszky’s disease, has a broad host range including most mammals and avian species. In 2011, a PRV variant emerged in many Bartha K61-vaccinated pig herds in China and has attracted more and more attention due to its serious threat to domestic and wild animals, and even human beings. The PRV variant has been spreading in China for more than 10 years, and considerable research progresses about its molecular biology, pathogenesis, transmission, and host–virus interactions have been made. This review is mainly organized into four sections including outbreak and genomic evolution characteristics of PRV variants, progresses of PRV variant vaccine development, the pathogenicity and transmission of PRV variants among different species of animals, and the zoonotic potential of PRV variants. Considering PRV has caused a huge economic loss of animals and is a potential threat to public health, it is necessary to extensively explore the mechanisms involved in its replication, pathogenesis, and transmission in order to ultimately eradicate it in China.

First Isolation and Molecular Characterization of Pseudorabies Virus in a Hunting Dog in Sicily (Southern Italy)

Pseudorabies virus (PrV) is the etiological agent of Aujeszky's disease, a viral infection that causes neurological lethal illness in mammals other than swine. Herein, we describe the occurrence of PrV infection in a hunting dog that had been bitten by an infected wild boar in Sicily, reporting for the first time genetic and phylogenetic data on the virus strain isolated in a dog in this Italian region. The dog was referred for severe neurological signs, respiratory distress, and intense itch around the muzzle. Death occurred within 48 h to the onset of clinical signs. On gross examination, self-induced skin lesions to the head due to intense itching and diffuse cerebral congestion were observed, whereas mild, aspecific, nonsuppurative meningitis was histologically diagnosed. Diffuse PrV positivity in neurons of the brainstem was observed by immunohistochemistry. PrV DNA was isolated and amplified from olfactory bulbs by nested PCR, targeting the viral glycoprotein G gene, and the sequence obtained matched with sequences of PrV isolates from dogs and wild boar. Isolation of PrV in the dog herein analysed denotes the spread of the virus in wild boar populations in Sicily and provides a proof of direct interspecies transmission. Thus, there is an urgent need to increase our understanding of the epidemiology of the PrV infection in wildlife to provide tools to trace possible spill over into domestic pigs or other livestock.

Retrieving Historical Cases of Aujeszky's Disease in Sicily (Italy): Report of a Natural Outbreak Affecting Sheep, Goats, Dogs, Cats and Foxes and Considerations on Critical Issues and Perspectives in Light of the Recent EU Regulation 429/2016

Aujeszky’s disease is caused by Suid alphaherpesvirus 1, and its main reservoir host is the pig. However, other species are also susceptible. Infection with this virus causes a severe neurological clinical picture named Aujeszky’s disease, usually accompanied by itching and death a few days after the onset of symptoms. This study reports a multi-species outbreak of Aujeszky’s disease that occurred in Sicily, which led to the death of 2 goats, 15 sheep, 2 dogs, 2 cats and 2 foxes. The diagnosis was made by culture, indirect immunofluorescence on brain samples and confirmed by biological test on rabbits. This study reports the first cases of Aujeszky’s disease in Italy in cats, goat and sheep. The finding of Aujeszky’s disease in several species in Sicily suggests a potential epizootic risk. In such areas where a multi-host system is recognised, an analysis of the risk factors should be carried out in order to develop targeted strategies for the control and eradication of the disease. The critical issues that hinder the control of Aujeszky’s disease in the studied territory and perspectives for eradication in the light of EU regulation 429/2016 are also discussed.

Canine parvovirus and pseudorabies virus coinfection as a cause of death in a wolf (Canis lupus) from southern Italy

Pseudorabies virus (PRV) or suid herpesvirus 1 (SHV‐1) is the causative agent of Aujeszky's disease, a highly contagious viral infection which causes neurological fatal illness in mammals other than suids. Here we report a case of a young wolf (Canis lupus) of around 2 years found dead by a hunter in the province of Avellino, Campania Region. Necropsy showed pathological findings consistent with encephalitis and gastroenteritis. Organs were analysed by microbiological and molecular investigations following standard procedures to ascertain the possible cause of death. Real‐time PCR revealed the presence of PRV in the brain and of canine parvovirus 2b in organs like intestine, liver, brain, kidney and pancreas. Death probably occurred very shortly after SHV‐1 infection in an animal already weakened by parvovirosis.