A Serological Survey of Brucellosis in Eurasian Wild Boar (Sus scrofa) in Campania Region, Italy

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.

Seroprevalence study of brucellosis in wild boar hunted for private consumption in northeast Portugal

Brucellosis is an important infectious disease caused by bacteria of the genus Brucella. In the northeast region of Portugal, infection with Brucella melitensis is endemic in small ruminants, and there are also humans' cases. However, the epidemiological role of the wild boar in the dynamics of this disease in this region is unknown. In this study, a total of 332 blood samples were collected from wild boar hunted in thirty-six hunting areas during the 2022/2023 hunting season. All were taken by the hunters for private consumption, with no evisceration or examination in the field. Serum samples were tested by indirect ELISA (i-ELISA). It was observed that 88 wild boars were exposed to Brucella spp., pointing to a seroprevalence of 26.5% (95% CI: 21.8 - 31.3%). This high prevalence underlines the importance that wild boar may have in the dynamics of this disease in the region and its potential transmission to other animals, and to humans (for example, during the handling of carcasses). Increased awareness and knowledge of brucellosis in wild boar is essential for the implementation of effective practices and habits and, consequently, for the control and prevention of this important zoonosis.

Pigs in southern Italy are exposed to three ruminant pathogens: an analysis of seroprevalence and risk factors analysis study

BACKGROUND

Pigs are susceptible to several ruminant pathogens, including Coxiella burnetti, Schmallenberg virus (SBV) and bovine viral diarrhea virus (BVDV). These pathogens have already been described in the pig population, although the dynamics of the infection and the impact on pig farms are currently unclear. The aim of this work was to evaluate the presence of these infections in the pig population of the Campania region, southern Italy, and to evaluate the risk factors associated with a greater risk of exposure.

RESULTS

A total of 414 serum samples belonging to 32 herds were tested for the presence of antibodies against SBV, Coxiella, and BVD using commercial multispecies ELISA kits. SBV (5.3%) was the most prevalent pathogen, followed by Coxiella (4.1%) and BVD (3%). The risk factors included in the study (age, sex, province, farming system, ruminant density and major ruminant species) had no influence on the probability of being exposed to BVD and Coxiella, except for the location, in fact more pigs seropositive to Coxiella were found in the province of Caserta. However, the univariate analysis highlighted the influence of age, location, and sex on exposure to SBV. The subsequent multivariate analysis statistically confirmed the importance of these factors. The presence of neutralizing antibodies for SBV and BVDV, or antibodies directed towards a specific phase of infection for Coxiella was further confirmed with virus-neutralization assays and phase-specific ELISAs in a large proportion of positive samples. The presence of high neutralizing antibody titers (especially for SBV) could indicate recent exposures. Twelve of the 17 positive samples tested positive for antibodies against Coxiella phase I or II antigens, indicating the presence of both acute and chronic infections (one animal tested positive for both phases antibodies).

CONCLUSIONS

Our study indicates a non-negligible exposure of pigs from southern Italy to the above pathogens. Further studies are necessary to fully understand the dynamics of these infections in pigs, the impact on productivity, and the public health consequences in the case of Coxiella.

Detection of selected pathogens in reproductive tissues of wild boars in the Campania region, southern Italy

Monitoring disease among wildlife is critical to preserving health in both domestic animals and wildlife, and it becomes much more critical when the diseases cause significant economic damage to the livestock industry or threaten public health. Given the continuous increase in populations and its role as a reservoir for several infections, wild boar (Sus scrofa) requires special attention regarding disease surveillance and monitoring. In this study, we investigated the molecular prevalence of selected pathogens in the wild boar population of Campania, southern Italy. The prevalence of pathogens causing reproductive problems in pigs (Sus domesticus), including porcine parvovirus (PPV), porcine circovirus types 2 and 3 (PCV-2 and PCV-3), pseudorabies virus (PRV), Coxiella burnetii, and Brucella suis, was evaluated by testing the reproductive organs collected from 63 wild boars with polymerase chain reaction. The most common pathogens were PPV (44.4%) and two porcine circoviruses (14.3%). PRV and C. burnetii, on the other hand, showed a significantly lower prevalence (1.6%). No reproductive organs tested were positive for B. suis. Risk factor analysis revealed a correlation between age and PCV-2 positivity, with animals less than 12 months old having significantly higher prevalence rates.Our findings suggest that wild boars hunted in the Campania region harbour several infections potentially transmissible to other mammals' reproductive tracts. Furthermore, our results emphasized the importance of strict adherence to biosecurity protocols on domestic swine farms, especially on free-range farms, to avoid interactions between domestic and wild animals.

Eleven Years of Health Monitoring in Wild Boars (Sus scrofa) in the Emilia-Romagna Region (Italy)

In recent years, the growth of wild ungulates has increased the focus on their health monitoring. In particular, the health status of wild boars is relevant for the economic impact on the pig industry. The Emilia-Romagna region activated a wildlife monitoring plan to better evaluate the health status of the wild boar population. Between 2011 and 2021, samples of found dead and hunted wild boar have been examined for trichinellosis, tuberculosis, brucellosis, african swine fever, classical swine fever, Aujeszky's disease, swine vesicular disease, and swine influenza A. Trichinella britovi was identified in 0.001% of the examined wild boars; neither M. bovis nor M. tuberculosis were found in M. tuberculosis complex positive samples; 2.3% were positive for Brucella suis; 29.4% of the sera were positive for Aujeszky's disease virus; and 0.9% of the samples were positive for swine influenza A virus. With an uncertain population estimate, the number of animals tested, the number of positives, and the sampling method do not allow us to make many inferences but suggest the need to implement and strengthen the existing surveillance activity, as it seems to be the only viable alternative for safeguarding animal and human health.

Presence of Foodborne Bacteria in Wild Boar and Wild Boar Meat-A Literature Survey for the Period 2012-2022

The wild boar is an abundant game species with high reproduction rates. The management of the wild boar population by hunting contributes to the meat supply and can help to avoid a spillover of transmissible animal diseases to domestic pigs, thus compromising food security. By the same token, wild boar can carry foodborne zoonotic pathogens, impacting food safety. We reviewed literature from 2012-2022 on biological hazards, which are considered in European Union legislation and in international standards on animal health. We identified 15 viral, 10 bacterial, and 5 parasitic agents and selected those nine bacteria that are zoonotic and can be transmitted to humans via food. The prevalence of Campylobacter, Listeria monocytogenes, Salmonella, Shiga toxin-producing E. coli, and Yersinia enterocolitica on muscle surfaces or in muscle tissues of wild boar varied from 0 to ca. 70%. One experimental study reported the transmission and survival of Mycobacterium on wild boar meat. Brucella, Coxiella burnetii, Listeria monocytogenes, and Mycobacteria have been isolated from the liver and spleen. For Brucella, studies stressed the occupational exposure risk, but no indication of meat-borne transmission was evident. Furthermore, the transmission of C. burnetii is most likely via vectors (i.e., ticks). In the absence of more detailed data for the European Union, it is advisable to focus on the efficacy of current game meat inspection and food safety management systems.

A Serological Investigation of Porcine Reproductive and Respiratory Syndrome and Three Coronaviruses in the Campania Region, Southern Italy

Porcine coronaviruses and reproductive and respiratory syndrome (PRRS) are responsible for severe outbreaks that cause huge economic losses worldwide. In Italy, three coronaviruses have been reported historically: porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV) and porcine respiratory coronavirus (PRCV). Although repeated outbreaks have been described, especially in northern Italy, where intensive pig farming is common, there is a worrying lack of information on the spread of these pathogens in Europe. In this work, we determined the seroprevalence of three porcine coronaviruses and PRRSV in the Campania region, southern Italy. A total of 443 samples were tested for the presence of antibodies against porcine coronaviruses and PRRSV using four different commercial ELISAs. Our results indicated that PEDV is the most prevalent among porcine coronaviruses, followed by TGEV, and finally PRCV. PRRSV appeared to be the most prevalent virus (16.7%). For coronaviruses, seroprevalence was higher in pigs raised in intensive farming systems. In terms of distribution, TGEV is more widespread in the province of Avellino, while PEDV and PRRSV are more prevalent in the province of Naples, emphasizing the epidemic nature of both infections. Interestingly, TGEV-positive animals are more common among growers, while seropositivity for PEDV and PRRSV was higher in adults. Our research provides new insights into the spread of swine coronaviruses and PRRSV in southern Italy, as well as a warning about the need for viral surveillance.

Seroprevalence and Risk Factors Investigations of Parvovirus Disease in Tibetan Pigs: First Report from Tibet

Porcine parvovirus (PPV) disease is a worldwide spread animal disease with high infection rate and serious impact on meat economy causing significant losses in livestock production. The purpose of this paper is to investigate and analyze the regional seroprevalence of PPV in Tibetan pigs in Tibet and evaluate risk factors related to the disease. A total of 356 serum samples of Tibetan pigs were collected from four counties and districts in Tibet, and anti-PPV antibodies were detected by using a commercial competitive ELISA. Our results show a seroprevalence of 91.01% (324 serum samples were found to be positive for anti-PPV antibodies). The positive rate among different district was 100%, 96.55%, 93.68% and 72.83%, respectively in the Mainling County, in Bayi district, Nang County and Bomê County. We found significant differences between different age and gender groups; particularly female animals show a seroprevalence of 96.03% while the males only 83.46%. From the perspective of the growth stage, our results indicate that subadults show a seroprevalence significative higher than other age groups (100%). This study describes for the first time the PPV seroprevalence among Tibetan pigs characterizing risk factors involved in its transmission and providing information to be taken into account for eventual surveillance or eradication plans.

Retrospective Serosurvey of Three Porcine Coronaviruses among the Wild Boar (Sus scrofa) Population in the Campania Region of Italy

The growing interest in porcine coronaviruses (CoVs) is due to both their negative effect on the swine industry and their propensity to mutate and overcome host barriers. Since information on CoVs in wild boar (Sus scrofa) is limited, especially in Italy, a serosurvey was conducted to assess the epidemiologic situation in the Campania region and to clarify the role of wild boar as reservoirs for enteric (porcine epidemic diarrhea virus [PEDV], transmissible gastroenteritis virus [TGEV]) and respiratory (respiratory coronavirus [PRCV]) swine CoVs. During the 2016-17 hunting season, serum samples were collected from 444 wild boars and tested for antibodies to enteric (PEDV, TGEV) and respiratory (PRCV) porcine CoVs by enzyme-linked immunosorbent assay. The highest seroprevalence in wild boars was for PEDV, with a positivity of 3.83% (95% confidence interval [CI] 2.05-5.6), whereas very low seroprevalences were found for TGEV and PRCV (0.67% positivity; 95% CI 0-1.44 in both cases). There was no statistical association between seropositivity to CoVs, sex, and location, whereas the prevalence of seropositive animals was positively correlated with young age (0-12 mo old). Our data confirm the presence of CoVs in wild boars in the Campania region. Our data are in agreement with the results of similar studies from other European countries, which attribute a minor role to wild boar in the transmission of these infections to domestic pigs. Our results suggest that continuous serologic surveys are necessary to monitor wild animals and detect emerging threats to livestock and humans.

Standardised Sampling Approach for Investigating Pathogens or Environmental Chemicals in Wild Game at Community Hunts

Simple Summary

Wild game can host pathogens capable of infecting humans, livestock, and companion animals or accumulate environmental chemicals that may be transferred via food of animal origin. For food safety research, as well as for various other scientific purposes, the provision of a sufficient number of samples without unnecessary disturbance or killing of animals is a major limitation. With the presented approach, it was possible to obtain samples from game animals killed as part of standard ungulate management practice. Examples of organs, tissues, and other matrices that have been used in wild ungulate studies in Europe and that may be obtained through this approach are summarised as well. The basis of this approach was a framework agreement with the BImA, whereby federal forest officials carried out sampling with the help of hunters at drive hunts from 2017/18 to 2020/21 in Brandenburg, Germany. Numerous samples from four ungulate species were obtained. The number of sampled animals per hunt differed between hunting districts and hunting seasons. Districts with higher hunting bags also promise higher sampling success. This approach can serve as the basis for long-term monitoring of animal and public health threats associated with wildlife and is adaptable to other regions.

Abstract

Wildlife may host pathogens and chemicals of veterinary and public health relevance, as well as pathogens with significant economic relevance for domestic livestock. In conducting research on the occurrence and distribution of these agents in wildlife, a major challenge is the acquisition of a sufficient number of samples coupled with efficient use of manpower and time. The aim of this article is to present the methodology and output of a sampling approach for game animals, which was implemented from 2017/18 to 2020/21 at drive hunts in Brandenburg, Germany. The central element was a framework agreement with the BImA, whereby federal forest officials and other hunters collected most of the samples during field dressing. Further samples of game carcasses were obtained by scientists during subsequent gathering at a collection point. Altogether, 3185 samples from 938 wild ungulates of four species were obtained for various studies analysing—in this case—food-borne agents in game animals. Sampling was representative and reflected the proportional distribution of ungulate species hunted in Brandenburg. Hunting district and hunting season strongly influenced hunting bag and hence sampling success. This sampling approach was demonstrated to be a suitable basis for monitoring programs, that can be adapted to other regions.

A Preliminary Study on Antimicrobial Susceptibility of Staphylococcus spp. and Enterococcus spp. Grown on Mannitol Salt Agar in European Wild Boar (Sus scrofa) Hunted in Campania Region-Italy

Simple Summary

During the last decade, an increase in the European wild boar (Sus scrofa) population occurred; thus, over the years, wild boars have become an important potential carrier of pathogenic bacteria for both livestock animals and pets, but also for humans. Since antibiotic resistance has become one of the greatest challenges of global public health, the aim of the present study was to define the prevalence and the antibiotic resistance profiles of bacteria grown on the selective medium mannitol salt agar (MSA), isolated from nasal swabs of wild boars hunted in Campania Region (southern Italy). The most prevalent isolated bacteria were represented by the Staphylococcus spp. and Enterococcus spp. strains, which showed worrying antibiotic-resistant profiles. Consequently, constant surveillance of wild boars is strongly recommended, in order to assess their role as reservoirs of antibiotic resistant bacteria and as sentinels of a possible environmental contamination.

Abstract

The importance of wild boar lies in its role as a bioindicator for the control of numerous zoonotic and non-zoonotic diseases, including antibiotic resistance. Mannitol Salt Agar (MSA) is a selective medium used for isolation, enumeration, and differentiation of pathogenic staphylococci. Other genera such as Enterococcus spp. are also salt tolerant and able to grow on MSA. The present study focused on the identification, by matrix assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS), of bacteria grown on MSA isolated from the nasal cavities of 50 healthy wild boars hunted in Campania Region (southern Italy) in the year 2019. In addition, the antimicrobial resistance phenotype of the isolated strains was determined by disk diffusion method. Among genus Staphylococcus, coagulase-negative Staphylococcus (CoNS) were the most common isolated species, with Staphylococcus xylosus as the most prevalent species (33.3%). Furthermore, Enterococcus spp. strains were isolated, and Enterococcus faecalis was the species showing the highest frequency of isolation (93.8%). For staphylococci, high levels of resistance to oxacillin (93.3%) were recorded. Differently, they exhibited low frequencies of resistance to tested non-β-lactams antibiotics. Among enterococci, the highest resistances were observed for penicillin (93.7%), followed by ampicillin (75%), and ciprofloxacin (68.7%). Interestingly, 43.7% of the isolated strains were vancomycin-resistant. In conclusion, this study reports the phenotypic antibiotic resistance profiles of Staphylococcus spp. and Enterococcus spp. strains isolated from nasal cavities of wild boars hunted in Campania Region, highlighting that these wild animals are carriers of antibiotic resistant bacteria.

Aujeszky's Disease in South-Italian Wild Boars (Sus scrofa): A Serological Survey

Simple Summary

Aujeszky’s disease (AD, pseudorabies) is a viral disease of suids caused by Suid Herpesvirus 1 (SHV-1) also referred as Aujeszky’s disease virus (ADV) or Pseudorabies virus (PRV). The aim of our study was to evaluate seroprevalence of AD in wild boar hunted in the Campania Region, during the 2016–2017 hunting season. A total of 503 serum samples from wild boars hunted in the provinces of Campania Region were tested for antibody against ADV using an ELISA assay. A Seroprevalence of 23.85% (120/503, 95% Confidence Interval (CI 95%: 20.15–27.55) was found. Gender was not significantly associated with of ADV seropositivity (p > 0.05), while the presence of ADV antibodies was statistically associated with age (>36-month, p < 0.0001) and location (Avellino, p = 0.0161).

Abstract

Aujeszky’s disease (AD, pseudorabies) is a viral disease of suids caused by Suid Herpesvirus 1 (SHV-1) also referred as Aujeszky’s disease virus (ADV) or Pseudorabies virus (ADV). Domestic pig and Wild boar (Sus scrofa) are the natural host, but many species can be infected with ADV. The aim of our study was to evaluate seroprevalence of AD in wild boar hunted in the Campania Region, during the 2016–2017 hunting season. A total of 503 serum samples from wild boars hunted in the provinces of Campania Region (Southern Italy) were collected and were tested for antibody against ADV using an AD, blocking ELISA assay. A Seroprevalence of 23.85% (120/503, 95% Confidence Interval (CI): 20.15–27.55) was found. Gender was not significantly associated with of ADV seropositivity (p > 0.05), while the presence of ADV antibodies was statistically associated with age (>36-month, p < 0.0001) and location (Avellino, p = 0.0161). Our prevalence values are like those obtained in 2010 in our laboratory (30.7%), demonstrating a constant circulation of ADV in the area.

Prevalence of Infection with Porcine Circovirus Types 2 and 3 in the Wild Boar Population in the Campania Region (Southern Italy)

In recent years, porcine circovirus (PCV) infection has been documented as an important and emerging health concern for livestock and wildlife worldwide. The purpose of the present study was to assess the molecular prevalence of PCV-2 and PCV-3 and to clarify the epidemiological role of wild boars in the circulation of this virus in Campania, Southern Italy. For this purpose, samples from several organs were collected during the hunting season 2017-2018 from 148 wild boars in the Campania region. Quantitative real-time PCR was used for the detection and quantification of PCV-2 and PCV-3 genomes. The combined prevalence of PCV-2 and PCV-3 was 74.32% in the wild boars tested. The proportions of wild boars positive for PCV-2 or PCV-3, or coinfected, were 47.30%, 49.32%, and 22.30%, respectively. No link was detected between PCV positivity and location, but gender was a risk factor for the disease (female; p < 0.0001; OR 0.29). Furthermore, our study provides a snapshot of PCV-2 and PCV-3 circulation in wild boars in the Campania region: our findings can help us to better understand the role of wildlife in PCV circulation.

Investigation of Genetic Relatedness of Brucella Strains in Countries Along the Silk Road

In this study, MLVA (multiple-locus variable-number tandem repeat analysis) genotype data of Brucella strains from 11 countries along the Silk Road were downloaded from the MLVAbank. MLVA data of strains were applied to the constructed Minimum Spanning Tree to explore the species/biovars distribution, geographic origins, and genetic relationships of the strains analyzed. Moreover, whole-genome sequencing–single-nucleotide polymorphism (WGS-SNP) phylogenetic analysis of the genome of Brucella melitensis strains from GenBank was performed to discriminate the relatedness of strains further and investigate the transmission pattern of B. melitensis brucellosis. A total of 1,503 Brucella strains were analyzed in this study: 431 Brucella abortus strains (29.8%), 1,009 B. melitensis strains (65.7%), and 63 Brucella suis strains (4.5%). B. melitensis biovar 3 was the dominant species and was shown to be widespread in all of the examined regions, suggesting that the prevention and surveillance of the B. melitensis population are a main challenge in these countries. A wide host spectrum was observed for this Brucella population; many animal reservoirs are a potential reason for the continuous brucellosis circulation in these countries. Although the B. abortus strains from the examined regions had common geographic origins, only a few shared genotypes were observed in different countries. These data revealed that the majority of B. abortus strains were spreading within the national borders. However, the B. melitensis strains from Italy originated from a Western Mediterranean lineage; strains from the other 10 countries originated from Eastern Mediterranean lineage, and this lineage was shared by strains from three to nine different countries, suggesting that the introduction and reintroduction of the disease in the 10 countries might have occurred in the past. Furthermore, the most shared MLVA-16 genotypes were formed in the B. melitensis strains from China, Kazakhstan, and Turkey, suggesting that the introduction and trade in sheep and goats have occurred frequently in these countries. WGS-SNP analysis showed that the B. melitensis in this study originated from the Malta (Italy) region. According to their territorial affiliation between four clade strains from these countries in genotype B, the absence of a clear differentiation suggests that strains continuously expand and spread in countries along with Silk Road. Active exchange and trade of animals (sheep and goats) among these countries are reasonable explanations. B. suis strains from different nations showed unique geographic origins and epidemiological characteristics. Therefore, there is an urgent need for the control of transfer and trade of infected sheep (goats) in countries along the Silk Road, namely, the strengthening of the entry–exit quarantine of sheep and goats and improvements in the diagnosis of animal brucellosis.

Seroprevalence of Ehrlichia spp., Anaplasma spp., Borrelia burgdorferi sensu lato, and Dirofilaria immitis in Stray Dogs, from 2016 to 2019, in Southern Italy

Canine vector-borne diseases (CVBD) are an important and emerging health concern for humans and animals worldwide. The purpose of the presented study was to assess, from 2016 to 2019, the seroprevalence of CVBD agents and clarify the epidemiology of tick-borne disease in stray dogs living in the Campania Region, Southern Italy. For this purpose, blood samples were collected from January 2016 to December 2019 from 1023 dogs in authorized kennels located in the five municipalities of the Campania Region. SNAP^® 4DX^® from IDEXX^® Laboratories was used for detection of Ehrlichia spp., Anaplasma spp., Borrelia burgdorferi sensu lato (s.l.), and Dirofilaria immitis antibodies. The overall seroprevalence of CVBD in stray dogs was 19.6% (95% Confidence Intervals (CI): 17.2-22.8%; 201/1023). The most common pathogen was Ehrlichia spp., with a percentage of positivity of 16.03%, followed by Anaplasma spp. with 7.8%. B. burgdorferi s.l. and D. immitis were detected in only 0.2% of dogs; co-infection was detected in 4.5% of stray dogs tested. No link was detected between the gender, age, location, and CVBD seropositivity, except for Ehrlichia spp. for which location (Avellino Province; p = 0.007) and gender (male, p = 0.002) were risk factors for seropositivity. Our results demonstrated that animals are exposed to at least one of the four etiological agents (Ehrlichia spp., Anaplasma spp. Borrelia burgdorferi s.l., and Dirofilaria immitis) transmitted by vectors. Finally, this study highlighted the utility of serological monitoring in stray dogs, housed in kennels, given the threat posed by CVBD to animals and the zoonotic implications of these etiological agents and their vectors on human health.