Findings of Alaria alata mesocercariae in wild boars (Sus scrofa) in eastern Austria

From June 2011 to February 2012, a total of 451 wild boar carcasses from eastern regions of Austria were tested for the presence of Alaria alata mesocercariae by means of a migration technique. Mesocercariae were recovered from carcasses from the province of Lower Austria (25/337 carcasses) and the Burgenland (5/64), but not from Vienna (0/50). In positive samples (fatty and glandular tissue and muscle), the median number of mesocercariae was 4.5 per 35?g. Within districts, but also between animals hunted at the same day in the same hunting area, frequencies of detection varied considerably.     

Prevalence of antibodies to porcine parvovirus in wild boars (Sus scrofa) in Croatia

Serologic evidence of exposure to porcine parvovirus (PPV) in the wild boar (Sus scrofa) in Croatia was investigated. Serum samples from 219 wild boars captured during 2003 from 12 different locations in the Republic of Croatia were tested by using a commercial enzyme-linked immunoassay (ELISA) and a hemagglutination inhibition (HI) test. Antibodies to PPV were detected in 91 (41.6%) of tested samples and positive results were detected in wild boar from all sample locations. Adults had a significantly higher prevalence (70%) than juveniles (31%; P < 0.01). Our results indicate that wild boar populations throughout the Republic of Croatia are exposed to PPV.     

Helminth infections of wild boars (Sus scrofa) in the Bursa province of Turkey

The present study aimed to investigate the status of helminth infections in wild boars in the Bursa province of Turkey. For this purpose, during 2007-2008, 27 wild boars were necropsied and examined for helminths. Individual samples of tongue and diaphragm from 27 necropsied wild boars and an additional 22 tongue and diaphragm samples provided by hunters were examined by trichinoscopy and artificial digestion for Trichinella spp. larvae. Twenty animals (74%) were identified as being infected with at least one helminth species. Twelve species of helminths were detected, with the following prevalence rates: Metastrongylus apri (59%), Metastrongylus salmi (52%), Metastrongylus pudendotectus (52%), Dicrocoelium dendriticum (33%), Globocephalus urosubulatus (22%), Macracanthorhynchus hirudinaceus (19%), Gongylonema pulchrum (11%), Physocephalus sexalatus (7%), Trichuris suis (7%), Ascarops strongylina (4%), Hyostrongylus rubidus (4%) and Taenia hydatigena larvae (4%). Generally, lungworms were the predominant helminths. The highest mean abundance was observed for M. pudendotectus, and the lowest was determined for T. hydatigena larvae. Significant differences in the prevalence and intensity were found for D. dendriticum with respect to host age and sex, respectively. The mean intensity of M. pudendotectus was significantly influenced by the sex and age of the wild boars. This study is the first report describing the presence of M. salmi, M. pudendotectus, D. dendriticum, G. urosubulatus, M. hirudinaceus, P. sexalatus, A. strongylina and H. rubidus in wild boars in Turkey. All analysed muscle samples were negative for Trichinella spp. larvae.     

Activity budgets and use of enclosed space by wild boars (Sus scrofa) in captivity

This research was conducted on a captive group of eight wild boars: Four wildborn adults (one male and three females) and four piglets (one male and three females), born in captivity two months before the beginning of the study. They were housed in the Rome Zoo in a 1,000 sq m enclosure furnished with trees, mud pools, a water basin, and two small barns. Data on eight behavioral states (sleeping, resting, rooting, eating, walking, standing, scratching, and nursing) were collected by instantaneous sampling at 10-minute intervals. The spatial location of each subject was also noted, as well as closeness to conspecifics. Results showed that adults and piglets differed in their activity budgets. Activity patterns showed a significant correlation with the mean temperatures. Furthermore, there was a significant difference in the use of the exhibit areas between adults and piglets. This study suggests a social structure in which the core is constituted by females and their yearlings. The nonbreeding female has a more marginal position than the breeding ones. Finally, the male tends to be even more peripheral and solitary. Our results are partly consistent with the data obtained in studies on free-ranging wild boars (Mauget, 1980; Dardaillon, 1984).     

Prevalence of Leptospira and Brucella antibodies in wild boars (Sus scrofa) in Tuscany, Italy

Five hundred sixty-two blood samples were collected from wild boars (Sus scrofa) shot in six districts of Tuscany, central Italy, between 1997 and 2000. Sera were examined for antibodies specific for Leptospira interrogans by microagglutination test and Brucella spp. by the Rose Bengal test and indirect enzyme-linked immunosorbent assay. Thirty-four (6.0%) samples tested positive for anti-Leptospira antibodies, 29 (5.1%) sera were positive for anti-L. interrogans serovar bratislava antibodies (titres ranging from 1:100-1:400), and 5 (0.9%) sera were positive for anti-L. interrogans serovar icterohaemorrhagiae antibodies (titres 1:100). All the examined sera were negative for anti-Brucella antibodies.     

Seroprevalence of Toxoplasma gondii and Trichinella spiralis infections in wild boars (Sus scrofa) in Korea

Toxoplasma gondii and Trichinella spiralis are important zoonotic pathogens with worldwide distributions. In Korea, several outbreaks of human toxoplasmosis and trichinellosis due to the consumption of infected wild animals have been reported. The purpose of this study was to determine the seroprevalence of T. gondii and T. spiralis infections in wild boars killed in Korea from December 2009 to October 2011. A total of 521 wild boars hunted in eight provinces were examined for antibodies to T. gondii and T. spiralis by using commercial ELISA kits. Overall, 25.1% of serum samples from individual boars were seropositive for T. gondii and 1.7% were seropositive for T. spiralis. Seropositive for T. gondii was found in the boars in all the eight provinces investigated and for T. spiralis in four provinces. This is the first report on the seroprevalence of T. gondii and T. spiralis infections in wild boars in Korea. The consumption of undercooked wild boar meat may expose humans to a high risk of infection.     

Grubbing by wild boars (Sus scrofa L.) and its impact on hardwood forest soil carbon dioxide emissions in Switzerland

Interest in soil C storage and release has increased in recent years. In addition to factors such as climate/land-use change, vertebrate animals can have a considerable impact on soil CO₂ emissions. To date, most research has considered herbivores, while the impact of omnivorous animals has rarely been investigated. Our goal was to determine how European wild boars (Sus scrofa L.), large omnivores that consume soil-inhabiting animals and belowground plant parts by grubbing in the soil, affect soil C dynamics. We measured soil respiration (CO₂), temperature, and moisture on paired grubbed and non-grubbed plots in six hardwood forest stands for a 3-year period and sampled fine root and microbial biomass at the beginning and after 2 years of the study. We also measured the percentage of freshly disturbed forest soil within the larger surroundings of each stand and used this information together with hunting statistics and forest cover data to model the total amount of CO₂ released from Swiss forest soils due to grubbing during 1 year. Soil CO₂ emissions were significantly higher on grubbed compared to non-grubbed plots during the study. On average 23.1% more CO₂ was released from these plots, which we associated with potential alterations in CO₂ diffusion rates, incorporation of litter into the mineral soil and higher fine root/microbial biomass. Thus, wild boars considerably increased the small-scale heterogeneity of soil properties. Roughly 1% of Switzerland’s surface area is similar to our sites (boar density/forest cover). Given the range of forest soil disturbance of 27–54% at our sites, the geographic information system model predicted that boar grubbing would lead to the release of an additional 49,731.10–98,454.74 t CO₂ year⁻¹. These values are relatively small compared to total soil emissions estimated for Swiss hardwood forests and suggest that boars will have little effect on large-scale emissions unless their numbers increase and their range expands dramatically.     

Grouping-patterns and inter-group relationships of Japanese wild boars (Sus scrofa leucomystax) in the Rokko mountain area

Grouping-patterns and inter-group relationships of Japanese wild boars (Sus scrofa leucomystax) were studied at a provisioning site in the Rokko mountain area, Hyogo Prefecture, Japan, from 1982 to 1983. The observations were divided into four study periods. Almost all wild boars were individually identified and their kin-relationships were followed from the beginning of the study. To examine grouping-patterns of Japanese wild boars, the degree of association between any two individuals, based on coexisting time at the provisioning site, was analyzed for each study period. Mother and her litter group (MLG), female littermate group (FLG) and solitary individual were recognized grouping-patterns. Groups did not associate with each other. Male offspring separated from their mother before 1 year of age and become solitary. Separation of female offspring occurred before the subsequent parturition of their mother. The proximate cause of separation was increased aggression by the mother. After separation, female offspring formed a FLG. However, the FLG seemed to be generally a temporary one, maintaining its stability only until parturition of it's members. Thereafter adult females had no close association with any other individuals, except for their own infants. Male offspring disappeared from their natal area, while female offspring could remain there.     

A methodological approach for non-invasive sampling for population size estimates in wild boars (Sus scrofa)

Composite microsatellite genotypes were determined at five loci from 35 tissue-sampled wild boars and used as reference genotypes to estimate both allelic drop-out rate and false allele rate in comparison to genotypes from scats and hair strands of the same animals. These rates allow to assess the genotyping reliability when only non-invasively collected material is available. Polymerase chain reaction (PCR) amplification from scats was often corrupted by inhibitors and worked poorly, whereas genotyping success in hair samples was high. Body region of hair origin had no influence on PCR suitability, whereas the type of hair had. We recommend the use of bristles. PCR conditions were optimized for single-hair (bristle) genotyping.     

Serosurveillance for selected infectious disease agents in wild boars (Sus scrofa) and outdoor pigs in Switzerland

The large abundance of free-ranging wild boars (Sus scrofa) and a trend towards animal friendly outdoor management of domestic pigs lead to an increasing probability of disease transmission between those animal populations. In 2001, an active monitoring was started for classical swine fever (CSF), Aujeszky’s disease (AD) and porcine brucellosis (PB) in wild boars in Switzerland. The objective of this programme was to document the serological status of wild boars regarding the selected pathogens. To continue this serosurveillance, 1,060 wild boar samples were collected during two regular hunting seasons in 2004–2005. Furthermore, in a pilot study, 61 outdoor pigs from 14 farms located in areas with high wild boar densities were sampled in 2004 and serologically tested for AD and PB. All wild boar samples were negative for CSF. Seroprevalence for AD was 2.83% (95% CI 1.91–4.02%). Seroprevalence for PB was 13.5% (95% CI 10.7–16.7%) for the Rose Bengal test and 11.05% (95% CI 8.82–13.61%) for the indirect ELISA. There was no serological evidence for AD in domestic pigs. All tested animals from 13 piggeries were seronegative for PB, but three pigs from the same farm showed doubtful results. Further investigations on the farm did not indicate the presence of PB in the herd. These findings urge the need for better diagnostic tools to obtain reliable results concerning PB prevalence. Since contact and following transmission of infectious agents between infected wild boars and outdoor pigs might occur in the future, it is advisable to include outdoor pigs in areas at risk in routine surveillance programmes.     

Chromosome translocations in the karyotypes of wild boars Sus scrofa L. of the European and the Asian areas of USSR

Summary The karyotypes of the 80 wild boars of the four subspecies, Sus scrofa ussuricus Heude from the Far East of USSR, S. s. nigripes Blanf. from Kirghizia (the Middle Asia), S. s. attila Thos. from Azerbaijan, S. s. ferus from Lithuania, Byelorussia and Central Russia, and the 44 domestic pigs of the five different breeds (Vietnamese Black, Siberian Omskaja Gray, Kakhethian-aborigen Georgian, Mangalica Hungarian, Landrace Swedish), were studied by the Giemsa Banding Method. Differential staining by the G-Method made it possible to identify all the homologous chromosomes of the wild and domestic pig karyotypes as well as to reveal the polymorphism of wild boar karyotypes (2n = 36, 37 and 38), which are determined by the two types of chromosome translocation. Crosses between domestic pigs (2n = 38) and wild boars (2n = 36 and 37) with different chromosome rearrangements might help to clarify the genetic function of the chromosomes A4, B3, B4, B5 and allow their use as genetic markers.     

Estimation of the fertility rates of Japanese wild boars (Sus scrofa leucomystax) using fetuses and corpora albicans

Effective population control of Japanese wild boar (Sus scrofa leucomystax) requires reliable information about population dynamics. Fertility rate is the fundamental component of reproduction to evaluate population dynamics. However, little is known regarding the fertility rate of Japanese wild boar. The traditional hunting practices make it difficult to obtain pregnant females and calculate the fertility rate by checking fetuses as is performed in other countries. Therefore, we focused on the corpora albicans (CA) as the CA remains in the ovaries of postpartum females after pregnancy. This study aimed to evaluate the utility of CA and estimate the fertility rate of Japanese wild boars using CA. Histological analysis of ovaries enabled us to discriminate type 1 CA, which remains for 1 year after breeding. Type 1 CA is a superior indicator compared with lactation in the non-pregnancy season because it allows verification of postpartum females over a long period. The fertility rate was calculated by the combination of pregnant and postpartum females using fetuses and type 1 CA from April to November. The fertility rate of the females captured after the second pregnancy season was 90.3 % during the pregnancy period and 100 % during the non-pregnancy period. The high fertility rate of adult females suggests that intensive adult female harvesting is needed. Our new method to determine fertility rates contributes to developing a monitoring system to adequately control Japanese wild boar population.     

Seroprevalence of Toxoplasma gondii in wild boars (Sus scrofa leucomystax) and wild sika deer (Cervus nippon) in Gunma Prefecture, Japan

The ingestion of undercooked meat from wild animals can be a source of Toxoplasma gondii infection in humans and other animals. In this study, we determined the seroprevalence of T. gondii infection in 175 wild boars (Sus scrofa leucomystax) and 107 wild sika deer (Cervus nippon) hunted in 2004–2007 in Gunma Prefecture, Japan, by using a commercial latex agglutination test (LAT). Antibodies (LAT, 1:64 or higher) to T. gondii were found in 6.3% of wild boars and 1.9% of sika deer. This is the first record of T. gondii infection in wild deer in Japan, and deer and wild boar meat should be cooked well before human consumption.     

Mortality rates of wild boar Sus scrofa L. in central Europe

In many parts of Europe, wild boar Sus scrofa population increase, and thus, high densities and dispersal into new areas are accompanied by economic problems. Due to many factors like insufficient hunting strategies as well as underestimation of population densities and reproduction rates, harvest rates seem to be insufficient. Thus, we calculated mortality rates of several wild boar populations from 1998 to 2009, to show the efficiency of hunting within several studies distributed over eight European states. For calculating mortality rates, the daily probability of survival of radio telemetrically observed wild boar was analysed according to Mayfield (Wilson Bull 73:255-261, 1961) and with survival analysis in R for three age classes (0, 1, ≥2 years) and both sexes. The mortality rates of wild boar per annum, especially piglets, were comparably low (about 0.5 for piglets and similar for total population). About three third of all observed animals survived at least until the next period of reproduction. Mortality rates differed between some study areas, the sexes and age classes. The sex ratio of the shot piglets equals the sex ratio of captured piglets; there seems to be no sex-biased hunting in this age class, but in an older age. Shooting was the main cause of death; only very few animals died by natural causes, e.g. diseases. The comparative analysis of all studies reflects a low mortality of wild boar in highly productive populations. Our results certified the findings of several studies that predation, natural mortality, and road mortality have only small impact on wild boar populations, whereas especially, nutrition or hunting are mainly decisive. Assuming net reproduction rates of more than 200 % according to literature data, our results indicate that harvest rates are not sufficient at our study sites. In all our studies, mortality rates and, thus, harvest rates are less than the assumed total net reproduction. Especially, the harvest rate of piglets seems to be insufficient. Thus, the population will increase further. High reproduction has to be counteracted by regulating mainly the reproductive animals. For regulating a population, combined and effective hunting methods have to be conducted to harvest at least the net reproduction. Thus, we recommend higher hunting rates of piglets (80 % of the offspring should be harvested) and of adult females. Intensified hunting of piglets by drive hunts and at an early age as well as intensified single hunt on adult females might help regulating wild boar populations.     

中国大陆野猪SLA DRB基因exon2的序列变异分析

本文基于135头野猪样本中检测到的15种SLA DRB基因exon 2序列的遗传变异分析,探讨DRB基因在不同地理区域中自然选择的变化特征.研究发现DRB基因exon 2抗原结合位点的非同义替换率为同义替换率的2.95倍,表明该位点受到平衡选择的强烈作用.在系统发生分析中,在基于核苷酸序列构建的NJ树中,野猪DRB位点的15种等位基因全部聚为一枝,没有发现跨种多态现象;而在基于氨基酸序列构建的系统发生树中,野猪SLA-DRB*nnu6和人DRB基因exon 2片段聚在一起,这种氨基酸残基的高度相似可能是由于自然选择压力下产生的趋同.野猪DRB基因exon 2的序列多态性分析表明,东北野猪基因多态性低于四川野猪和华南野猪,这可能与不同气候条件和地理环境下的寄生虫等因素对SLA等位基因变异的影响存在差异有关.     

The effect of season on the properties of wild boar (Sus scrofa L.) semen

The objective of the study was to determine the properties of wild boar semen and their changes in annual cycle. During a 14-month study period, 167 ejaculates were sampled from 3 mature boars. In each ejaculate the volume of liquid fraction, percentage of spermatozoa motility, spermatozoa concentration and the total number of spermatozoa were determined. The activity of acid and alkaline phosphatase, and aspartate aminotransferase in the fresh semen plasma was also measured. It was shown that wild boar ejaculates did not differ from those of domestic boars, and the semen of the highest volume, concentration and number of spermatozoa was produced in late autumn. The spermatozoa motility was the lowest in summer. The activity of aspartate aminotransferase and alkaline phosphatase in the semen plasma increased with shortening of the light period.