Management of a Focal Introduction of ASF Virus in Wild Boar: The Belgian Experience.

African swine fever (ASF) is a fatal disease of suids that was detected in wild boar in Belgium in September 2018. The measures implemented to stop the spread and eliminate the African swine fever virus consisted of creating restriction zones, organising efficient search and removal of carcasses, constructing wire fences, and depopulating wild boar in the area surrounding the infected zone. The ASF management zone included the infected and the white zones and covered 1106 km² from which 7077 wild boar have been removed. A total of 5338 wild boars have been qPCR-tested and 833 have been detected ASF-positive. The search effort amounted to 60,631 h with a main focus on the infected zone (88%). A total of 277 km of fences have been set up. The main cause of mortality in the infected zone was the virus itself, while hunting, trapping, and night shooting were used together to reduce the wild boar density in the surrounding white zones. After continuous dispersion of the virus until March 2019, the epidemic wave stopped, and the last fresh positive case was discovered in August 2019. Hence, Belgium was declared free of the disease in November 2020.

Population genetics, invasion pathways and public health risks of the raccoon and its roundworm Baylisascaris procyonis in northwestern Europe.

The geographic range of the zoonotic raccoon roundworm (Baylisascaris procyonis) is expanding together with the range of its host, the raccoon (Procyon lotor). This creates a new public health risk in parts of Europe where this parasite was previously absent. In the Netherlands, a raccoon population is becoming established and incidental findings of B. procyonis have been reported. To assess the risk to public health, the prevalence of B. procyonis was determined in the province of Limburg, where currently the largest Dutch raccoon population is present, as well as in the adjoining region of southern Belgium. Furthermore, genetic methods were employed to assess invasion pathways of both the raccoon and B. procyonis to aid in the development of control measures. Macroscopic analysis of intestinal content and testing of faecal samples were performed to detect B. procyonis adults and eggs. The population genetics of both B. procyonis and its raccoon host were analysed using samples from central and northwestern Europe. B. procyonis was found in 14/23 (61%, 95% CI: 41%-78%) raccoons from Limburg, but was not detected in 50 Belgian raccoons. Genetic analyses showed that the majority of the Dutch raccoons and their roundworms were introduced through ex-captive individuals. As long as free-living raccoon populations originate from captivity, population control methods may be pursued. However, natural dispersal from the border regions will complicate prolonged population control. To reduce the public health risk posed by B. procyonis, public education to increase awareness and adapt behaviour towards raccoons is key.

Schmallenberg virus, cyclical reemergence in the core region: A seroepidemiologic study in wild cervids, Belgium, 2012-2017.

Schmallenberg virus emerged in 2011 in Europe. The epicentre of primordial spreading was the region straddling Germany, the Netherlands and Belgium. One of the key questions is whether the newcomer would establish a lasting presence on the continent. The apparent seroprevalence in southern Belgium wild deer populations was followed for 6 years. Two years of intense circulation were revealed, 2012 and 2016, characterized by a peak seroprevalence in the two studied populations (Capreolus capreolus and Cervus elaphus). Between the peak years and after 2016, apparent seroprevalences declined rapidly among adults and became nil among juveniles. The general pattern of apparent seroprevalence evolution observed is consistent with a cyclic circulation of Schmallenberg virus, similar to what is observed for other Orthobunyaviruses in endemic areas. These data also suggest that wild cervids play no central role in the circulation dynamics of the virus.

Newly emerged African swine fever virus strain Belgium/Etalle/wb/2018: Complete genomic sequence and comparative analysis with reference p72 genotype II strains.

In a new example of pathogens hopscotching the globe, African swine fever virus hit north-western Europe's wildlife in summer 2018, marking a further spread of a disease that had invaded Central and Eastern Europe recently. The complete genomic sequence of the Belgium/Etalle/wb/2018 virus is reported, with the hope it will provide a valuable tool for tracing geographical spread and biologic evolution of the virus.

First Evidence of Fatal Usutu Virus Natural Infections in an Anatidae, the Common Scoter (Melanitta nigra).

While fatal infections caused by the Usutu virus appeared to concern only passerines (especially the blackbird) and Strigiformes (especially the great gray owl), we report herein that the virus also naturally causes a fatal disease in an anseriforme species, the common scoter (Melanitta nigra).

A novel parvovirus, Roe deer copiparvovirus, identified in Ixodes ricinus ticks.

The family Parvoviridae contains diverse viruses that are capable of infecting a wide range of hosts. In this study, metagenomic sequencing of Ixodes ricinus ticks harvested in 2016 on red deer (Cervus elaphus) and European roe deer (Capreolus capreolus) in Belgium detected a new 6296-bp parvoviral genome. Phylogenetic and sequence analyses showed the new virus belongs to a new species within the Copiparvovirus genus. PCR screening of 4 pools of 10 serum samples from both deer species identified the new copiparvovirus DNA only in roe deer sera. Together, these results are the first evidence of a copiparvovirus in a deer species. Besides its potential pathogenicity to roe deers, the detection of this new virus in ticks raises questions about the possible transmission of parvoviruses by ticks. This report further increases the current knowledge on the evolution and diversity of copiparvoviruses.

Phylogeographic Analysis of African Swine Fever Virus, Western Europe, 2018.

In September 2018, African swine fever in wild boars was detected in Belgium. We used African swine fever-infected spleen samples to perform a phylogenetic analysis of the virus. The causative strain belongs to genotype II, and its closest relatives are viruses previously isolated in Ukraine, Belarus, Estonia, and European Russia.

Molecular evidence of Anaplasma phagocytophilum in wild boar (Sus scrofa) in Belgium.

BACKGROUND: Anaplasma phagocytophilum is a tick-borne pathogen of veterinary and human importance. Both ticks as vectors and vertebrates as reservoir hosts are essential for the cycle maintenance of this bacterium. Currently, the whole range of animal species reservoirs for A. phagocytophilum in natural environment is still unknown. Therefore, the aim of this study was to estimate the prevalence of infection with A. phagocytophilum in the wild boar population in southern Belgium. RESULTS: In the frame of a targeted surveillance program, 513 wild boars were sampled during the hunting season 2011. A nested 16S rRNA PCR was used to screen the presence of A. phagocytophilum DNA in spleen of boars. Within 513 samples, 5 (0,97%) were tested PCR positive and identification was confirmed by sequencing. CONCLUSIONS: This study gives the first insight of presence of A. phagocytophilum in wild boars in southern Belgium.

Epizootic spread of Schmallenberg virus among wild cervids, Belgium, Fall 2011.

Schmallenberg virus was detected in cattle and sheep in northwestern Europe in 2011. To determine whether wild ruminants are also susceptible, we measured antibody seroprevalence in cervids (roe deer and red deer) in Belgium in 2010 and 2011. Findings indicated rapid spread among these deer since virus emergence ≈250 km away.