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Park SL, Huang YJS, Lyons AC, Ayers VB, Hettenbach SM, McVey DS, Noronha LE, Burton KR, Higgs S, Vanlandingham DL. Infection of Feral Phenotype Swine with Japanese Encephalitis Virus. Vector Borne Zoonotic Dis 2023; 23:645-652. [PMID: 37672628 PMCID: PMC10698774 DOI: 10.1089/vbz.2023.0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023] Open
Abstract
Background: Japanese encephalitis virus (JEV) is a mosquito-borne zoonotic flavivirus and the leading cause of pediatric encephalitis in the Asian Pacific region. The transmission cycle primarily involves Culex spp. mosquitoes and Ardeid birds, with domestic pigs (Sus scrofa domestica) being the source of infectious viruses for the spillover of JEV from the natural endemic transmission cycle into the human population. Although many studies have concluded that domestic pigs play an important role in the transmission cycle of JEV, and infection of humans, the role of feral pigs in the transmission of JEV remains unclear. Since domestic and feral pigs are the same species, and because feral pig populations in the United States are increasing and expanding geographically, the current study aimed to test the hypothesis that if JEV were introduced into the United States, feral pigs might play a role in the transmission cycle. Materials and Methods: Sinclair miniature pigs, that exhibit the feral phenotype, were intradermally inoculated with JEV genotype Ib. These pigs were derived from crossing miniature domestic pig with four strains of feral pigs and were used since obtaining feral swine was not possible. Results: The Sinclair miniature pigs became viremic and displayed pathological outcomes similar to those observed in domestic swine. Conclusion: Based on these findings, we conclude that in the event of JEV being introduced into the United States, feral pig populations could contribute to establishment and maintenance of a transmission cycle of JEV and could lead to the virus becoming endemic in the United States.
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Affiliation(s)
- So Lee Park
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, Kansas, USA
| | - Yan-Jang S. Huang
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, Kansas, USA
| | - Amy C. Lyons
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, Kansas, USA
| | - Victoria B. Ayers
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, Kansas, USA
| | - Susan M. Hettenbach
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, Kansas, USA
| | - D. Scott McVey
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Leela E. Noronha
- Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, Agricultural Research Service, United States Department of Agriculture, Manhattan, Kansas, USA
| | - Kenneth R. Burton
- Biosecurity Research Institute, Kansas State University, Manhattan, Kansas, USA
| | - Stephen Higgs
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, Kansas, USA
| | - Dana L. Vanlandingham
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, Kansas, USA
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Schuh AJ, Amman BR, Guito JC, Graziano JC, Sealy TK, Towner JS. Tick salivary gland components dampen Kasokero virus infection and shedding in its vertebrate reservoir, the Egyptian rousette bat (Rousettus aegyptiacus). Parasit Vectors 2023; 16:249. [PMID: 37488618 PMCID: PMC10367358 DOI: 10.1186/s13071-023-05853-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/27/2023] [Indexed: 07/26/2023] Open
Abstract
BACKGROUND The human-pathogenic Kasokero virus (KASV) circulates in an enzootic transmission cycle between Egyptian rousette bats (ERBs; Rousettus aegyptiacus) and their argasid tick ectoparasites, Ornithodoros (Reticulinasus) faini. Although tick salivary gland components have been shown to potentiate virus infection in vertebrate non-reservoirs (i.e. incidental hosts or small animal models of disease), there is a lack of information on the effect of tick salivary gland components on viral infection and shedding in vertebrate reservoirs. METHODS To determine the impact of tick salivary gland components on KASV infection and shedding in ERBs, KASV loads were quantified in blood, oral swab, rectal swab, and urine specimens collected daily through 18 days post inoculation from groups of ERBs intradermally inoculated with KASV or KASV + O. (R.) faini tick salivary gland extract (SGE). RESULTS Bats inoculated with KASV + tick SGE had significantly lower peak and cumulative KASV viremias and rectal shedding loads compared to bats inoculated with KASV only. CONCLUSIONS We report for the first time to our knowledge that tick salivary gland components dampen arbovirus infection and shedding in a vertebrate reservoir. This study advances our understanding of biological factors underlying arbovirus maintenance in nature.
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Affiliation(s)
- Amy J Schuh
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, United States Centers for Disease Control and Prevention, Atlanta, GA, USA.
- United States Public Health Service Commissioned Corps, Rockville, MD, USA.
| | - Brian R Amman
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, United States Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jonathan C Guito
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, United States Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - James C Graziano
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, United States Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Tara K Sealy
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, United States Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jonathan S Towner
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, United States Centers for Disease Control and Prevention, Atlanta, GA, USA.
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Re-Examining the Importance of Pigs in the Transmission of Japanese Encephalitis Virus. Pathogens 2022; 11:pathogens11050575. [PMID: 35631096 PMCID: PMC9146973 DOI: 10.3390/pathogens11050575] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/05/2022] [Accepted: 05/11/2022] [Indexed: 01/27/2023] Open
Abstract
Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is the leading cause of pediatric encephalitis in Southeast Asia. The enzootic transmission of JEV involves two types of amplifying hosts, swine and avian species. The involvement of pigs in the transmission cycle makes JEV a unique pathogen because human Japanese encephalitis cases are frequently linked to the epizootic spillover from pigs, which can not only develop viremia to sustain transmission but also signs of neurotropic and reproductive disease. The existing knowledge of the epidemiology of JEV largely suggests that viremic pigs are a source of infectious viruses for competent mosquito species, especially Culex tritaeniorhynchus in the endemic regions. However, several recently published studies that applied molecular detection techniques to the characterization of JEV pathogenesis in pigs described the shedding of JEV through multiple routes and persistent infection, both of which have not been reported in the past. These findings warrant a re-examination of the role that pigs are playing in the transmission and maintenance of JEV. In this review, we summarize discoveries on the shedding of JEV during the course of infection and analyze the available published evidence to discuss the possible role of the vector-free JEV transmission route among pigs in viral maintenance.
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