scholarly journals Dynamics of Classical Swine Fever Spread in Wild Boar in 2018–2019, Japan

Pathogens ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 119 ◽  
Author(s):  
Norikazu Isoda ◽  
Kairi Baba ◽  
Satoshi Ito ◽  
Mitsugi Ito ◽  
Yoshihiro Sakoda ◽  
...  
Keyword(s):  
Wild Boar ◽  
Euclidean Distance ◽  
Classical Swine Fever ◽  
Control Measures ◽  
Anthropogenic Factors ◽  
Epidemiological Analysis ◽  
Period Prevalence ◽  
Positive Rate ◽  
In The Wild ◽  
Spatiotemporal Analyses

The prolongation of the classic swine fever (CSF) outbreak in Japan in 2018 was highly associated with the persistence and widespread of the CSF virus (CSFV) in the wild boar population. To investigate the dynamics of the CSF outbreak in wild boar, spatiotemporal analyses were performed. The positive rate of CSFV in wild boar fluctuated dramatically from March to June 2019, but finally stabilized at approximately 10%. The Euclidean distance from the initial CSF notified farm to the farthest infected wild boar of the day constantly increased over time since the initial outbreak except in the cases reported from Gunma and Saitama prefectures. The two-month-period prevalence, estimated using integrated nested Laplace approximation, reached >80% in half of the infected areas in March–April 2019. The area affected continued to expand despite the period prevalence decreasing up to October 2019. A large difference in the shapes of standard deviational ellipses and in the location of their centroids when including or excluding cases in Gunma and Saitama prefectures indicates that infections there were unlikely to have been caused simply by wild boar activities, and anthropogenic factors were likely involved. The emergence of concurrent space–time clusters in these areas after July 2019 indicated that CSF outbreaks were scattered by this point in time. The results of this epidemiological analysis help explain the dynamics of the spread of CSF and will aid in the implementation of control measures, including bait vaccination.

scholarly journals Efficacy of Oral Vaccine against Classical Swine Fever in Wild Boar and Estimation of the Disease Dynamics in the Quantitative Approach

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 319
Author(s):  
Enkhbold Bazarragchaa ◽  
Norikazu Isoda ◽  
Taksoo Kim ◽  
Madoka Tetsuo ◽  
Satoshi Ito ◽  
...  
Keyword(s):  
Wild Boar ◽  
Oral Vaccine ◽  
Classical Swine Fever ◽  
Control Measures ◽  
Wild Boar Population ◽  
Oral Vaccination ◽  
Wild Boars ◽  
In The Wild ◽  
High Virus ◽  
Gifu Prefecture

Classical swine fever virus (CSFV) in the wild boar population has been spreading in Japan, alongside outbreaks on pigs, since classical swine fever (CSF) reemerged in September 2018. The vaccination using oral bait vaccine was initially implemented in Gifu prefecture in March 2019. In the present study, antibodies against CSFV in wild boar were assessed in 1443 captured and dead wild boars in Gifu prefecture. After the implementation of oral vaccination, the increase of the proportion of seropositive animals and their titer in wild boars were confirmed. Quantitative analysis of antigen and antibodies against CSFV in wild boar implies potential disease diversity in the wild boar population. Animals with status in high virus replication (Ct < 30) and non- or low-immune response were confirmed and were sustained at a certain level after initial oral vaccination. Through continuous vaccination periods, the increase of seroprevalence among wild boar and the decrease of CSFV-positive animals were observed. The epidemiological analysis based on the quantitative virological outcomes could provide more information on the efficacy of oral vaccination and dynamics of CSF in the wild boar population, which will help to improve the implementation of control measures for CSF in countries such as Japan and neighboring countries.

scholarly journals Role of Wild Boar in the Spread of Classical Swine Fever in Japan

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 206 ◽  
Author(s):  
Ito ◽  
Jurado ◽  
Bosch ◽  
Ito ◽  
Sánchez-Vizcaíno ◽  
...  
Keyword(s):  
Wild Boar ◽  
Spatial Association ◽  
Classical Swine Fever ◽  
Temporal Analysis ◽  
Control Measures ◽  
Domestic Pig ◽  
Potential Contact ◽  
Spatio Temporal ◽  
Epidemiological Characteristics ◽  
Gifu Prefecture

Since September 2018, nearly 900 notifications of classical swine fever (CSF) have been reported in Gifu Prefecture (Japan) affecting domestic pig and wild boar by the end of August 2019. To determine the epidemiological characteristics of its spread, a spatio-temporal analysis was performed using actual field data on the current epidemic. The spatial study, based on standard deviational ellipses of official CSF notifications, showed that the disease likely spread to the northeast part of the prefecture. A maximum significant spatial association estimated between CSF notifications was 23 km by the multi-distance spatial cluster analysis. A space-time permutation analysis identified two significant clusters with an approximate radius of 12 and 20 km and 124 and 98 days of duration, respectively. When the area of the identified clusters was overlaid on a map of habitat quality, approximately 82% and 75% of CSF notifications, respectively, were found in areas with potential contact between pigs and wild boar. The obtained results provide information on the current CSF epidemic, which is mainly driven by wild boar cases with sporadic outbreaks on domestic pig farms. These findings will help implement control measures in Gifu Prefecture.

scholarly journals Does the infection with endoparasites influence the effect of oral vaccination against classical swine fever in wild boar?

2015 ◽  
Vol 84 (3) ◽  
pp. 225-230
Author(s):  
Anna Ondrejková ◽  
Ondrej Kiš ◽  
Juraj Ciberej ◽  
Katarína Oberhauserová ◽  
Róbert Ondrejka ◽  
...  
Keyword(s):  
Wild Boar ◽  
Classical Swine Fever ◽  
Viral Disease ◽  
Economic Losses ◽  
Parasitic Infections ◽  
Oral Vaccination ◽  
Specific Antibodies ◽  
Antibody Titres ◽  
In The Wild ◽  
Direct Elisa

Classical swine fever is a highly contagious viral disease that affects domestic and wild suids and could cause important economic losses. It is the most dangerous infectious disease of the wild boar that can cause severe death in densely populated areas. The aim of the study was to determine the effect of endoparasites on the oral vaccination against classical swine fever in wild boar. The study compared classical swine fever antibody titres in wild boar treated and untreated with antiparasitics. Fourteen six-month-old wild boar piglets were tested via direct ELISA to detect specific antibodies in blood serum after vaccination. Before the vaccination, one group of piglets was administered antiparasitic therapy; the other group of animals remained untreated. Twenty-eight days post vaccination, piglets from the first group (free of parasites) showed significantly (P = 0.0015) higher concentrations of specific antibodies than the infected animals. Obtained results proved that parasitic infections substantially influence the efficacy of oral vaccination against classical swine fever and may support the ability of the virus to produce infectious diseases and its transmission in the wild boar population. For that reason, antiparasitic therapy of wild boar populations before their vaccination is highly recommended in order to increase the vaccine’s efficacy.

scholarly journals Epidemiological analysis of classical swine fever in wild boars in Japan

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Yumiko Shimizu ◽  
Yoko Hayama ◽  
Yoshinori Murato ◽  
Kotaro Sawai ◽  
Emi Yamaguchi ◽  
...  
Keyword(s):  
Wild Boar ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Classical Swine Fever ◽  
Disease Spread ◽  
Wild Boar Population ◽  
Wild Boars ◽  
First Case ◽  
Forest Continuity ◽  
In The Wild

Abstract Background Classical swine fever (CSF) is a contagious disease of pigs and wild boars that is transmitted through direct/indirect contact between animals or CSF virus-contaminated fomites. When the disease re-emerged in 2018 in Japan, a CSF-infected wild boar was reported shortly after the initial pig farm outbreak; subsequently, the disease spread widely. To control the disease spread among wild boars, intensive capturing, fencing, and oral bait vaccination were implemented with concomitant virological and serological surveillance. This study aimed to describe the disease spread in the wild boar population in Japan from September 2018, when the first case was reported, to March 2020, based on the surveillance data. We conducted statistical analyses using a generalized linear mixed model to identify factors associated with CSF infection among wild boars. Moreover, we descriptively assessed the effect of oral bait vaccination, which started in March 2019 in some municipalities in the affected areas. Results We observed a faster CSF infection spread in the wild boar population in Japan compared with the CSF epidemics in European countries. The infection probability was significantly higher in dead and adult animals. The influence of the multiple rounds of oral bait vaccination was not elucidated by the statistical modeling analyses. There was a decrease and increase in the proportion of infected and immune animals, respectively; however, the immunization in piglets remained insufficient after vaccination for 1 year. Conclusions Conditions regarding the wild boar habitat, including forest continuity, higher wild boar population density, and a larger proportion of susceptible piglets, were addressed to increase the infection risk in the wild boar population. These findings could improve the national control strategy against the CSF epidemic among wild boars.

scholarly journals What Do Lithuanian Hunters Think of African Swine Fever and Its Control—Perceptions

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 525
Author(s):  
Evelina Stončiūtė ◽  
Katja Schulz ◽  
Alvydas Malakauskas ◽  
Franz J. Conraths ◽  
Marius Masiulis ◽  
...  
Keyword(s):  
Wild Boar ◽  
Surveillance System ◽  
African Swine Fever ◽  
Study Data ◽  
Control Measures ◽  
Attitudes And Beliefs ◽  
Passive Surveillance ◽  
Wild Boar Population ◽  
In The Wild ◽  
Governmental Institutions

After the introduction of African swine fever (ASF) into Lithuania in 2014, continuous spread of the disease resulted in infection of the wild boar populations in most parts of Lithuania. The virus has been moving closer to other Western European countries where pig density is high. An efficient surveillance system detecting ASF cases early in domestic and wild animals is necessary to manage this disease. To make surveillance appropriate and effective, it is critical to understand how key players perceive the implemented control measures. This study investigated the attitudes and beliefs of hunters in Lithuania regarding currently implemented or proposed measures for the control of ASF in the wild boar population. Study data were collected through questionnaires distributed via the internet and by hunting associations in Lithuania. In total, 621 fully completed questionnaires were received and analyzed. All measures interfering with extensive hunting, like ban of driven or individual hunting or ban of supplementary feeding were considered as unacceptable and as ineffective measures to control ASF in wild boar. However, selective hunting of female wild boar was generally considered as an unethical act and therefore rejected. Some measures that seem to have been successful in other countries, like involvement of additional forces, were rejected by Lithuanian hunters, thus implementation of these measures could be difficult. The study highlighted that there is a need for improving important relationships with other stakeholders, since many hunters expressed a lack of trust in governmental institutions and regarded cooperation with them as insufficient. Hunters emphasized that their motivation to support passive surveillance measures could be improved with financial compensation and reduction of workload. The present study provides insights into hunters’ perceptions, which may be used as a foundation for additional discussions with these important stakeholders and for adapting measures to improve their acceptance if appropriate.

scholarly journals African Swine Fever in Wild Boar in Europe—A Review

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1717
Author(s):  
Carola Sauter-Louis ◽  
Franz J. Conraths ◽  
Carolina Probst ◽  
Ulrike Blohm ◽  
Katja Schulz ◽  
...  
Keyword(s):  
Wild Boar ◽  
Case Fatality ◽  
African Swine Fever ◽  
Hemorrhagic Fever ◽  
Spatial Behavior ◽  
Control Measures ◽  
Disease Spread ◽  
Domestic Pigs ◽  
In The Wild ◽  
Socio Economic Impact

The introduction of genotype II African swine fever (ASF) virus, presumably from Africa into Georgia in 2007, and its continuous spread through Europe and Asia as a panzootic disease of suids, continues to have a huge socio-economic impact. ASF is characterized by hemorrhagic fever leading to a high case/fatality ratio in pigs. In Europe, wild boar are especially affected. This review summarizes the currently available knowledge on ASF in wild boar in Europe. The current ASF panzootic is characterized by self-sustaining cycles of infection in the wild boar population. Spill-over and spill-back events occur from wild boar to domestic pigs and vice versa. The social structure of wild boar populations and the spatial behavior of the animals, a variety of ASF virus (ASFV) transmission mechanisms and persistence in the environment complicate the modeling of the disease. Control measures focus on the detection and removal of wild boar carcasses, in which ASFV can remain infectious for months. Further measures include the reduction in wild boar density and the limitation of wild boar movements through fences. Using these measures, the Czech Republic and Belgium succeeded in eliminating ASF in their territories, while the disease spread in others. So far, no vaccine is available to protect wild boar or domestic pigs reliably against ASF.

scholarly journals Estimation of the Lethality Rate, Recovery Rate, and Case Fatality Ratio of Classical Swine Fever in Japanese Wild Boar: An Analysis of the Epidemics From September 2018 to March 2019

2021 ◽  
Vol 8 ◽  
Author(s):  
Ryota Matsuyama ◽  
Takehisa Yamamoto ◽  
Yoko Hayama ◽  
Ryosuke Omori
Keyword(s):  
Population Dynamics ◽  
Wild Boar ◽  
Recovery Rate ◽  
Case Fatality ◽  
Classical Swine Fever ◽  
Accurate Estimation ◽  
Detailed Data ◽  
Wild Boar Population ◽  
Case Fatality Ratio ◽  
In The Wild

Understanding the morbidity and lethality of diseases is necessary to evaluate the effectiveness of countermeasure against the epidemics (e.g., vaccination). To estimate them, detailed data on host population dynamics are required; however, estimating the population size for wildlife is often difficult. We aimed to elucidate the morbidity and lethality of classical swine fever (CSF) currently highly prevalent in the wild boar population in Japan. To this end, we estimated lethality rate, recovery rate, and case fatality ratio (CFR) of CSF without detailed data on the population estimates of wild boar. A mathematical model was constructed to describe the CSF dynamics and population dynamics of wild boar. We fitted the model to the (i) results of the reverse transcription polymerase chain reaction (RT-PCR) test for the CSFV gene and the (ii) results of the enzyme-linked immunosorbent assay (ELISA) test for the antibody against CSFV in sampled wild boar. In the 280 wild boar sampled from September 2018 to March 2019 in the major CSF-affected area in Japan, the lethality rate and recovery rate of CSF per week were estimated as 0.165 (95% confidence interval: 0.081–0.250) and 0.004 (0–0.009), respectively. While the estimate of lethality rate of CSF was similar with the estimates in previous studies, the recovery rate was lower than those reported previously. CFR was estimated as 0.959 (0.904–0.981) using our estimate of recovery rate. This study is the first to estimate lethality rate of CSF from the dynamics of CSF epidemics in the wild boar population. Since the value of CFR is sensitive to the value of recovery rate, the accuracy in the estimate of recovery rate is a key for the accurate estimation of CFR. A long-term transmission experiment of moderately virulent strains may lead to more accurate estimation of the recovery rate and CFR of CSF.

scholarly journals Etiological, epidemiological, and clinical features of acute diarrhea in China

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Li-Ping Wang ◽  
◽  
Shi-Xia Zhou ◽  
Xin Wang ◽  
Qing-Bin Lu ◽  
...  
Keyword(s):  
Clinical Features ◽  
Acute Diarrhea ◽  
Vibrio Parahaemolyticus ◽  
Bacterial Pathogens ◽  
Control Measures ◽  
Viral Pathogens ◽  
Rotavirus A ◽  
Positive Rate ◽  
Prevention And Control Measures ◽  
And Control

AbstractNational-based prospective surveillance of all-age patients with acute diarrhea was conducted in China between 2009‒2018. Here we report the etiological, epidemiological, and clinical features of the 152,792 eligible patients enrolled in this analysis. Rotavirus A and norovirus are the two leading viral pathogens detected in the patients, followed by adenovirus and astrovirus. Diarrheagenic Escherichia coli and nontyphoidal Salmonella are the two leading bacterial pathogens, followed by Shigella and Vibrio parahaemolyticus. Patients aged <5 years had higher overall positive rate of viral pathogens, while bacterial pathogens were more common in patients aged 18‒45 years. A joinpoint analysis revealed the age-specific positivity rate and how this varied for individual pathogens. Our findings fill crucial gaps of how the distributions of enteropathogens change across China in patients with diarrhea. This allows enhanced identification of the predominant diarrheal pathogen candidates for diagnosis in clinical practice and more targeted application of prevention and control measures.

scholarly journals Prevalence and Antimicrobial Resistances of Salmonella spp. Isolated from Wild Boars in Liguria Region, Italy

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 568
Author(s):  
Elisabetta Razzuoli ◽  
Valeria Listorti ◽  
Isabella Martini ◽  
Laura Migone ◽  
Lucia Decastelli ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Wild Boar ◽  
Antimicrobial Susceptibility ◽  
Potential Risk ◽  
Salmonella Enterica ◽  
Intestinal Tract ◽  
Wild Boar Population ◽  
Salmonella Spp ◽  
Wild Boars ◽  
In The Wild

Salmonella spp. is an important zoonotic agent. Wild boars might host this pathogen in the intestinal tract and might represent a risk for Salmonella spp. transmission to humans. Wild boars are widely spread in Liguria, due to the environmental characteristics of the region. The aim of the study was the isolation, typing, and investigation of antimicrobial susceptibility of the isolated strains of Salmonella spp. During the 2013–2017 hunting seasons, 4335 livers of wild boars were collected and analyzed for the presence of Salmonella spp. A total of 260 strains of Salmonella spp. were isolated and characterized, with a prevalence of 6%. The isolated strains belonged to all six Salmonella enterica subspecies. Most of them were identified as Salmonella enterica subs. enterica of which 31 different serotypes were identified. The dominating serotype identified was S. Enteritidis. The antimicrobial resistance profiles of the isolated strains were analyzed against sixteen molecules. Of the isolated strains, 94.6% were resistant to at least one of the tested antimicrobials. This study showed the circulation of resistant Salmonella spp. strains in the wild boar population living in this area of Italy, underling the potential risk for these animals to disseminate this pathogen and its antimicrobial resistances.

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