Detection of Pseudorabies Virus in Wild Boar Foetus: Comparison
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Pseudorabies, or Aujeszky’s disease, is a notifiable worldwide infection of domestic and feral swine that causes economic losses for the swine industry. In domestic pigs, the virus is responsible for nervous and/or respiratory symptoms; in pregnant sows, it is one of the major causes of stillbirth, mummification, embryonic death, and infertility (SMEDI). It is known that PRV infection in wild boar is associated with low pathogenicity and attenuated or absent symptomatology, but limited information is available about the ability of the virus to infect the foetuses of infected wild boar pregnant sows. Due to scarce information about the reproductive consequences, we investigate the possible intrauterine vertical transmission of the virus in wild boar pregnant sow living in a highly infected area. A number of 54 hunted wild boar were sampled during 2018–2019, and blood, genital and nasal swabs, placenta, and fetuses were collected for serological and molecular investigations. A seroprevalence of 74% (40/54) was detected, while 1/24 pregnant sow and 1/24 pooled foetuses tested positive by PCR (gene gB). This is the first evidence of viral detection in foetuses from seropositive pregnant wild boar. This finding suggests the possible pathogenetic role of PRV on pregnancy in wild boar and the existence of an additional transmission route.

  • pseudorabies virus
  • wild boar
  • Italy
  • foetus
  • Suid alphaherpesvirus 1
  • transmission route

1. Introduction

Introduction

Pseudorabies (PR) or Aujeszky’s disease is a notifiable worldwide infection of domestic and feral and wild swine that was first described in the early twentieth century 

[1][2]

. The disease is characterised by neurological and reproductive porcine disorders causing economic losses for the swine industry.

The causative agent is Suid herpesvirus 1 (SuHV-1), also known as pseudorabies virus (PRV), or Aujeszky’s disease virus (ADV), a member of the family Herpesviridae, subfamily Alphaherpesvirinae, genus Varicellovirus 

[2]

.

PRV can infect many species, but despite its wide host range, which includes nearly all mammals, the natural hosts for PRV are members of the Suidae family, in particular domestic pigs and wild boar. In these animals, the virus is able to establish a lifelong latent infection in neuronal and non-neuronal cells, so swine and wild boar survive the infection and behave like a reservoir of PRV

[3][4]

.

2. PRV in Pigs

In pigs, PRV transmission mainly occurs by an oro-nasal route due to the high density of swine in farms, which allows for nose-to-nose contact and disease shedding. The venereal transmission has been suggested as the main route in feral swine and wild boar

In pigs, PRV transmission mainly occurs by an oro-nasal route due to the high density of swine in farms, which allows for nose-to-nose contact and disease shedding. The venereal transmission has been suggested as the main route in feral swine and wild boar

[2][5][6]

. Higher viral seroprevalence in females, along with the presence of viral DNA in nasal secretions, suggests that PRV is mainly transmitted oro-nasally within female groups throughout the year, whereas venereal transmission is limited to the mating season

[3][6][7]

. Secondary routes of transmission are through contact with fomites or by ingestion of contaminated carcasses of other infected animals, such as feral swine, wild boar, rodents, or carnivores

[2][8][9]

.

Due to great economic impact on the swine industry, most of the European countries have implemented eradication programs with the purpose of eradicating PRV and guaranteeing free trade within Europe

[10]

.

Since the 1980s, PR has spread globally due to the changes in swine management with the rise of intensive farming and to the appearance of highly virulent strains of PRV

[2][11]

. Therefore, infection, prevention, and control plans including large-scale vaccination with gE-deleted vaccines have been put in place in farmed pigs. To date, the disease has been eradicated within the domestic pig population in several European nations such as Denmark, Finland, Austria, France, Germany, Hungary, Switzerland, Sweden, Slovakia

[2]

. Canada, New Zealand, and the United States have been declared as “Aujeszky’s Disease-free”

[12][13]

.

On the other hand, in countries where domestic pigs are PRV free, the virus is almost always present in an endemic form in wild boar

[10]

. In fact, the PRV seroprevalence in wild boar in European countries ranges from 4% to 66%, and therefore it is important to understand the epidemiology of the virus in this species in order to avoid the possibility of relapses in pigs or infection of other susceptible animals

[2][6][10][14][15][16][17][18][19][20][21][22]

.
To gain information concerning the epidemiology of the virus, genetic characterisation of circulating PRV genotypes can be helpful.
PRVs are classified by the Restriction Fragment Length Polymorphism (RFLP) analysis in four major types and several subtypes

[4]

 : genotype I, found mainly in the USA and in Central Europe; genotypes II and III, circulating in Northern Europe and Central Europe; and genotype IV, which is limited to Asia

[2][23]

.
In Europe, while genotype 1 mainly circulates in wild boar, both genotype 1 and 2 have been detected in domestic pigs even if the latter is much more widespread

[20]

.
In Italy, although the National Authority has implemented an eradicating program adopting severe and restrictive measures, the virus has undergone a substantial reduction in circulation in pig farms but has not yet been eradicated; furthermore, it is widely spread within the wild boar population

[10][24]

.
In adult domestic pigs, the virus is responsible for respiratory symptoms of different severities that can determine the worsening of the general health condition, loss of weight and appetite, and therefore a decrease in production performance. While in adult pigs morbidity is very high and mortality is around 1%–2%, in piglets, there are nervous symptoms, including tremors, convulsions, and paralysis, leading to death in 100% of cases. In pregnant sows, the infection, as well as the reactivation of the virus, leads to stillbirth, mummification, embryonic death, and infertility (SMEDI) with embryo resorption, foetal mummification, abortion, or stillbirth based on the month in which the virus reaches the placenta

[25][26][27][28][29]

.
Unfortunately, little is known about the symptomatology of the disease in wild boar. So far, it is known that PRV infection in free-ranging wild boar is associated with low pathogenicity and attenuated or absent symptomatology with only mild respiratory symptoms. Limited information is available about the ability of infected wild boar pregnant sows to carry out the pregnancy

[2][15][17][30]

.

Due to scarce information about the reproductive consequences of PRV infection, we investigate the implications of the virus in wild boar pregnant sow living in a highly infected PRV area.

The article has been published on 10.3390/ani10020366 

References

  1. Aujeszky, Aladar;  Ueber eine neue Infektionskrankheit bei Haustieren. Centralblatt für Bakteriologie, Parasitenkunde und Infektionskrankheiten 1902, 32, 353-357.
  2. T. Müller; E. C. Hahn; F. Tottewitz; M. Kramer; B. G. Klupp; T. C. Mettenleiter; C. Freuling; Pseudorabies virus in wild swine: a global perspective. Archives of Virology 2011, 156, 1691-1705, 10.1007/s00705-011-1080-2.
  3. Jose F. Ruiz-Fons; Dolo Vidal; Ursula Höfle; Joaquin Vicente; Christian Gortazar; M Dolors Vidal; Aujeszky's disease virus infection patterns in European wild boar. Veterinary Microbiology 2007, 120, 241-250, 10.1016/j.vetmic.2006.11.003.
  4. King, A.M.Q.; Adams, M.J.; Carstens, E.B.; Lefkowitz, E.J. Herpesvirales. In Virus Taxonomy; Elsevier:  Amsterdam, The Netherlands, 2012; pp. 99–107.
  5. C. H. Romero; Paul N. Meade; Joseph E. Shultz; Hyun Y. Chung; E. Paul Gibbs; Edwin C. Hahn; Gene Lollis; VENEREAL TRANSMISSION OF PSEUDORABIES VIRUSES INDIGENOUS TO FERAL SWINE. Journal of Wildlife Diseases 2001, 37, 289-296, 10.7589/0090-3558-37.2.289.
  6. Ranieri Verin; Paolo Varuzza; Maurizio Mazzei; A. Poli; SEROLOGIC, MOLECULAR, AND PATHOLOGIC SURVEY OF PSEUDORABIES VIRUS INFECTION IN HUNTED WILD BOARS (SUS SCROFA) IN ITALY. Journal of Wildlife Diseases 2014, 50, 559-565, 10.7589/2013-01-004.
  7. David González-Barrio; Maria Paz Martín-Hernando; Jose F. Ruiz-Fons; Shedding patterns of endemic Eurasian wild boar (Sus scrofa) pathogens. Research in Veterinary Science 2015, 102, 206-211, 10.1016/j.rvsc.2015.08.014.
  8. E.C. Hahn; G.R. Page; P.S. Hahn; K.D. Gillis; C. Romero; J.A. Annelli; E.P.J. Gibbs; Mechanisms of transmission of Aujeszky's disease virus originating from feral swine in the USA. Veterinary Microbiology 1997, 55, 123-130, 10.1016/s0378-1135(96)01309-0.
  9. Felipe Hernandez; Katherine A. Sayler; Courtney Bounds; Michael P. Milleson; Amanda N. Carr; Samantha Wisely; EVIDENCE OF PSEUDORABIES VIRUS SHEDDING IN FERAL SWINE (SUS SCROFA) POPULATIONS OF FLORIDA, USA. Journal of Wildlife Diseases 2018, 54, 45-53, 10.7589/2017-04-071.
  10. Ana Moreno; Enrica Sozzi; Guido Grilli; Lucia Rita Gibelli; Daniela Gelmetti; Davide Lelli; Mario Chiari; Paola Prati; Giovanni Loris Alborali; Maria Beatrice Boniotti; et al.Antonio LavazzaPaolo Cordioli Detection and molecular analysis of Pseudorabies virus strains isolated from dogs and a wild boar in Italy. Veterinary Microbiology 2015, 177, 359-365, 10.1016/j.vetmic.2015.04.001.
  11. Lisa Pomeranz; Ashley E. Reynolds; Christoph J. Hengartner; Molecular Biology of Pseudorabies Virus: Impact on Neurovirology and Veterinary Medicine. Microbiology and Molecular Biology Reviews 2005, 69, 462-500, 10.1128/MMBR.69.3.462-500.2005.
  12. S C MacDiarmid; Aujeszky's disease eradication in New Zealand.. Australian Veterinary Journal 2000, 78, 470-471, 10.1111/j.1751-0813.2000.tb11862.x.
  13. Edwin C. Hahn; Bahaa Fadl-Alla; Carol A. Lichtensteiger; Variation of Aujeszky's disease viruses in wild swine in USA. Veterinary Microbiology 2010, 143, 45-51, 10.1016/j.vetmic.2010.02.013.
  14. Adriana, A.; Porea, D.; Aniţă, D.; Savuţa, G. SEROLOGICAL STUDY OF SELECTED VIRAL PATHOGENS  IN WILD BOAR FROM EASTERN ROMANIA. Development of translational research capacity: development of  vaccines from concept to preclinical evaluation View project REGIONAL CENTER OF ADVANCED RESEARCH  FOR EMERGING D; Lucrări ştiinţifice: Romania, 2015
  15. Caruso, Claudio Vitale, Nicoletta Prato, Riccardo Radaelli, Maria Cristina Zoppi, Simona Possidente, Rosaria Dondo, Alessandro Chiavacci, Laura Maria, Ana Martin, Moreno Masoero, Loretta Chiave Età, Parole;  Pseudorabies virus in North‐West Italian wild boar (Sus scrofa) populations: prevalence  and risk factors to support a territorial risk‐based surveillance. Veterinaria Italiana 2018, 54, 337-341.
  16. Joaquin Vicente; Luis León-Vizcaíno; Christian Gortazar; María José Cubero; Mónica González; Pablo Martín-Atance; Antibodies to Selected Viral and Bacterial Pathogens in European Wild Boars from Southcentral Spain. Journal of Wildlife Diseases 2002, 38, 649-652, 10.7589/0090-3558-38.3.649.
  17. J. Vicente; Jose F. Ruiz-Fons; M Dolors Vidal; Ursula Höfle; Pelayo Acevedo; D. Villanua; Isabel García Fernandez De Mera; M. P. Martin; Christian Gortazar; Serosurvey of Aujeszky's disease virus infection in European wild boar in Spain.. Veterinary Record 2005, 156, 408-412, 10.1136/vr.156.13.408.
  18. G Vengust; Zdravko Valencak; Andrej Bidovec; Presence of Antibodies Against Aujeszky's Disease Virus in Wild Boar (Sus scrofa) in Slovenia. Journal of Wildlife Diseases 2005, 41, 800-802, 10.7589/0090-3558-41.4.800.
  19. Kamil Sedlak; Eva Bártová; Jirina Machova; Antibodies to Selected Viral Disease Agents in Wild Boars from the Czech Republic. Journal of Wildlife Diseases 2008, 44, 777-780, 10.7589/0090-3558-44.3.777.
  20. T. Muller; B. G. Klupp; C. Freuling; B. Hoffmann; M. Mojcicz; I. Capua; V. Pálfi; B. Toma; W. Lutz; Jose F. Ruiz-Fons; et al.C. GortárzarA. HlinakU. SchaarschmidtK. ZimmerFranz ConrathsE. C. HahnT. C. Mettenleiter Characterization of pseudorabies virus of wild boar origin from Europe. Epidemiology and Infection 2010, 138, 1590-1600, 10.1017/s0950268810000361.
  21. G. Pannwitz; C. Freuling; N. Denzin; U. Schaarschmidt; H. Nieper; A. Hlinak; S. Burkhardt; M. Klopries; J. Dedek; L. Hoffmann; et al.M. KramerThomas SelhorstFranz ConrathsT. MettenleiterT. Muller A long-term serological survey on Aujeszky's disease virus infections in wild boar in East Germany. Epidemiology and Infection 2011, 140, 348-358, 10.1017/s0950268811000033.
  22. Francisco Javier Cano-Manuel; Jorge Ramón López Olvera; Paulino Fandos; Ramon Soriguer; Jesús M. Pérez; José Enrique Granados; Long-term monitoring of 10 selected pathogens in wild boar (Sus scrofa) in Sierra Nevada National Park, southern Spain. Veterinary Microbiology 2014, 174, 148-154, 10.1016/j.vetmic.2014.06.017.
  23. Herrmann, S.‐C.; Heppner, B.; Ludwig, H. Pseudorabies Viruses from Clinical Outbreaks and Latent  Infections Grouped into Four Major Genome Types. In Latent Herpes Virus Infections in Veterinary Medicine;  Springer: Amsterdam, The Netherlands, 1984; pp. 387–401
  24. Andrea Lari; Davide Lorenzi; Daniele Nigrelli; Emiliana Brocchi; Silvia Faccini; A. Poli; PSEUDORABIES VIRUS IN EUROPEAN WILD BOAR FROM CENTRAL ITALY. Journal of Wildlife Diseases 2006, 42, 319-324, 10.7589/0090-3558-42.2.319.
  25. Spradbrow, P.B. Veterinary virology. Vet. Microbiol. 1990, 21, 380–381
  26. Craig, R.A. Diseases of swine,; Wiley‐Blackwell: New Jersey, USA 2011
  27. Wittmann, G. Aujeszky’s disease (pseudorabies) in pigs; Springer: Berlin, Germany1989
  28. Xiuling Yu; Zhi Zhou; Ngmei Hu; Qian Zhang; Tao Han; Xiaoxia Li; Xiaoxue Gu; Lin Yuan; Shuo Zhang; Baoyue Wang; et al.Ping QuJinhua LiuXinyan ZhaiKegong Tian Pathogenic Pseudorabies Virus, China, 2012. Emerging Infectious Diseases 2014, 20, 102-104, 10.3201/eid2001.130531.
  29. K. V. Papageorgiou (Κ.β. Παπαγεωργιου); A. R. Burriel; G. Filioussis (Γ. Φιλιουσησ); V. Psychas (Β. Ψυχασ); H. Nauwynck; S. Kritas (Σ.κ. Κρητασ); Aujeszky's Disease (Pseudorabies). An old threat in current pig industry? Part I. Pathogenetic information and implications. Journal of the Hellenic Veterinary Medical Society 2017, 62, 29-37, 10.12681/jhvms.14833.
  30. F S Hsu; R M Chu; R C Lee; S H Chu; Placental lesions caused by pseudorabies virus in pregnant sows.. Journal of the American Veterinary Medical Association 1980, 177, 636-641.
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