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Aims: Zoonotic arboviruses (arthropod‐borne) of the Orthoflavivirus genus, such as West Nile virus (WNV), Usutu virus (USUV) and Tick‐borne encephalitis virus (TBEV), are emerging in Northwestern Europe and pose a threat to both human and animal health. In the Netherlands, passive symptomatic surveillance (notification of clinical cases) in horses is one of the main pillars for the early detection of WNV. For such passive surveillance to work properly, horse owners and veterinarians need to recognize symptoms and report suspected cases to the authorities. Currently, little is known about the seroprevalence of orthoflaviviruses in domestic animals in the Netherlands. Therefore, this study aims at identifying the seroprevalence of WNV and USUV in horses and dogs in the Netherlands. Additionally, this study seeks to evaluate the knowledge and perceptions of Dutch horse owners towards mosquito‐borne viruses. Methods and Results: A cross‐sectional serosurvey in horses and dogs was conducted between May 2021 and May 2022. Serum samples were screened using an ELISA and doubtful and positive samples were confirmed by Virus Neutralization Tests for WNV, USUV and TBEV. A validated questionnaire, the MosquitoWise survey, was used to assess the knowledge and perceptions of Dutch horse owners towards mosquito‐borne viruses between July and October 2022. The serosurvey revealed a low seroprevalence for WNV in horses and no WNV‐positive dogs were found. Similarly, a low USUV seroprevalence was found in dogs. The MosquitoWise survey revealed a high knowledge level for horse owners and high awareness of WNV vaccination but a more limited intent to vaccinate. Conclusions: The low seroprevalences of WNV and USUV indicate many dogs and horses remain susceptible, offering opportunities for trend analysis and surveillance. However, despite multiple recent detections of WNV, USUV, and TBEV in humans, the role of dogs and horses in early detection of human cases is debatable. High awareness among horse owners and the absence of detected equine WNV cases highlight this uncertainty. Continued surveillance is crucial for detecting increased virus circulation and protecting both animal and human health. [ABSTRACT FROM AUTHOR]

Starting December 2019, a novel coronavirus (SARS-CoV-2) spread among humans across the world. From 2020 onward, farmed mink were found susceptible to the virus. In this paper, we describe the Dutch surveillance system and the added surveillance components for early detection of SARS-CoV-2 outbreaks and their results in Dutch mink farms. In the Netherlands, a surveillance system was in place in which mink farmers could submit carcasses for postmortem evaluation and could contact a telephone helpdesk for veterinary advise. Through this system, the first SARS-CoV-2 outbreak in two mink farms was detected in April 2020. Immediately, the Dutch Ministry of Agriculture commissioned a consortium of statutory and research institutes to intensify the surveillance system. The program consisted of both passive surveillance, i.e., mandatory notifications and active surveillance components, i.e., serological screenings and weekly risk-based sampling of dead mink for early detection of new SARS-CoV-2 infections. When one of the surveillance components indicated a suspicion of a possible SARS-CoV-2 infection, follow-up samplings were conducted and at confirmation, all mink were culled. During 2020, 67 out of 124 mink farms that were under surveillance became infected with SARS-CoV-2 (54%). Of these, 31 were detected based on clinical signs (passive surveillance of clinical signs) and 36 were detected through active surveillance. From the mink farms with a new SARS-CoV-2 outbreak that was detected through the surveillance, in 19% of the farms (n = 7), the mink never showed any clinical signs of SARS-CoV-2 and might have been missed by the passive notification system. This study underlines the added value of a surveillance system that can quickly be intensified. The subsequent combination of both passive and active surveillance has shown to be effective in the early detection of emerging pathogens, which is important to minimize the risk of zoonotic spill-over. [ABSTRACT FROM AUTHOR]

In the Netherlands, 69 of the 126 (55%) mink farms in total became infected with SARS‐CoV‐2 in 2020. Despite strict biosecurity measures and extensive epidemiological investigations, the main transmission route remained unclear. A better understanding of SARS‐CoV‐2 transmission between mink farms is of relevance for countries where mink farming is still common practice and can be used as a case study to improve future emerging disease preparedness. We assessed whether SARS‐CoV‐2 spilled over from mink to free‐ranging animals, and whether free‐ranging animals may have played a role in farm‐to‐farm transmission in the Netherlands. The study encompassed farm visits, farm questionnaires, expert workshops and SARS‐CoV‐2 RNA and antibody testing of samples from target animal species (bats, birds and free‐ranging carnivores). In this study, we show that the open housing system of mink allowed access to birds, bats and most free‐ranging carnivores, and that direct and indirect contact with mink was likely after entry, especially for free‐ranging carnivores and birds. This allowed SARS‐CoV‐2 exposure to animals entering the mink farm, and subsequent infection or mechanical carriage by the target animal species. Moreover, mink can escape farms in some cases, and two SARS‐CoV‐2‐positive mink were found outside farm premises. No other SARS‐CoV‐2‐RNA‐positive free‐ranging animals were detected, suggesting there was no abundant circulation in the species tested during the study period. To investigate previous SARS‐CoV‐2 infections, SARS‐CoV‐2 antibody detection using lung extracts of carcasses was set up and validated. One tested beech marten did have SARS‐CoV‐2 antibodies, but the closest SARS‐CoV‐2‐infected mink farm was outside of its home range, making infection at a mink farm unlikely. Knowing that virus exchange between different species and the formation of animal reservoirs affects SARS‐CoV‐2 evolution, continued vigilance and monitoring of mink farms and surrounding wildlife remains vital. [ABSTRACT FROM AUTHOR]

Infection with hepatitis E virus (HEV) is common in both developing and industrialized nations. Genotypes 3 and 4 are increasingly being reported, particularly in high‐income countries where the precise extent of HEV transmission via food is currently unclear. Recently, HEV has been found to be excreted in milk; however, data on the potential milk‐borne transmission is still lacking or conflicting and warrants further research on the topic. As such, the aim of the present study was to review the current scientific knowledge and to summarize the existing studies in which HEV has been detected in milk. Exhaustive searches were carried out in Mendeley, PubMed, Scopus and Web of Science. A total of 157 papers were retrieved from the four electronic databases. After removing duplicate articles from the databases (n = 30), exclusion criteria identified unrelated research (n = 115). This allowed the identification of 12 eligible papers. To date, studies on HEV detection in milk were mostly from China (n = 5), followed by Egypt (n = 2), Germany (n = 1), Belgium and Holland (n = 1), Turkey (n = 1), Czech Republic (n = 1) and Spain (n = 1) and were focused on a variety of animals (cow, goat, donkey, buffalo, sheep and camel) and humans. Four out of the 12 eligible studies did not find any evidence of HEV in milk. Moreover, 3 out of the 12 studies detected low rates of HEV (0.2–1.8%) and two were based on a low sample size (n = 1 and n = 4). Interestingly, one study showed very high detection rates and also detected HEV genotype 1 in an animal milk sample, an unusual finding since it only occurs in humans, deserving further studies for confirmation and characterization. Two studies detected high prevalence of HEV genotype 4 in bovine samples from China, with one showing indication of the presence of infectious HEV in milk. To date, there is still a small amount of available data on the HEV presence in milk, posing important questions regarding both animal and human health. Thus, further efforts on this potentially underestimated zoonotic route for HEV should be given, warranting further studies on the topic. [ABSTRACT FROM AUTHOR]

Angiotensin converting enzyme 2 (ACE2) is a host cell membrane protein (receptor) that mediates the binding of coronavirus, most notably SARS coronaviruses in the respiratory and gastrointestinal tracts. Although SARS‐CoV‐2 infection is mainly confined to humans, there have been numerous incidents of spillback (reverse zoonoses) to domestic and captive animals. An absence of information on the spatial distribution of ACE2 in animal tissues limits our understanding of host species susceptibility. Here, we describe the distribution of ACE2 using immunohistochemistry (IHC) on histological sections derived from carnivores, ungulates, primates and chiroptera. Comparison of mink (Neovison vison) and ferret (Mustela putorius furo) respiratory tracts showed substantial differences, demonstrating that ACE2 is present in the lower respiratory tract of mink but not ferrets. The presence of ACE2 in the respiratory tract in some species was much more restricted as indicated by limited immunolabelling in the nasal turbinate, trachea and lungs of cats (Felis catus) and only the nasal turbinate in the golden Syrian hamster (Mesocricetus auratus). In the lungs of other species, ACE2 could be detected on the bronchiolar epithelium of the sheep (Ovis aries), cattle (Bos taurus), European badger (Meles meles), cheetah (Acinonyx jubatus), tiger and lion (Panthera spp.). In addition, ACE2 was present in the nasal mucosa epithelium of the serotine bat (Eptesicus serotinus) but not in pig (Sus scrofa domestica), cattle or sheep. In the intestine, ACE2 immunolabelling was seen on the microvillus of enterocytes (surface of intestine) across various taxa. These results provide anatomical evidence of ACE2 expression in a number of species which will enable further understanding of host susceptibility and tissue tropism of ACE2 receptor‐mediated viral infection. [ABSTRACT FROM AUTHOR]

The author reflects on schmallenberg virus (SBV) diagnostics. The author mentions the use of reverse-transcriptase polymerase chain reaction (RT-PCR) as diagnostics protocol for SBV, targeting the S segment. He states that SBV antibody testing in precolostral serum or body fluids is a useful diagnostic procedure for calves and lambs with congenital arthrogryposis hydroencephaly syndrome.