Highly pathogenic avian influenza A(H5N1) virus infections on fur farms connected to mass mortalities of black-headed gulls, Finland, July to October 2023.

Highly pathogenic avian influenza (HPAI) has caused widespread mortality in both wild and domestic birds in Europe 2020-2023. In July 2023, HPAI A(H5N1) was detected on 27 fur farms in Finland. In total, infections in silver and blue foxes, American minks and raccoon dogs were confirmed by RT-PCR. The pathological findings in the animals include widespread inflammatory lesions in the lungs, brain and liver, indicating efficient systemic dissemination of the virus. Phylogenetic analysis of Finnish A(H5N1) strains from fur animals and wild birds has identified three clusters (Finland I-III), and molecular analyses revealed emergence of mutations known to facilitate viral adaptation to mammals in the PB2 and NA proteins. Findings of avian influenza in fur animals were spatially and temporally connected with mass mortalities in wild birds. The mechanisms of virus transmission within and between farms have not been conclusively identified, but several different routes relating to limited biosecurity on the farms are implicated. The outbreak was managed in close collaboration between animal and human health authorities to mitigate and monitor the impact for both animal and human health.

Highly pathogenic avian influenza A(H5N1) virus infection on multiple fur farms in the South and Central Ostrobothnia regions of Finland, July 2023.

Since mid-July 2023, an outbreak caused by highly pathogenic avian influenza A(H5N1) virus clade 2.3.4.4b genotype BB is ongoing among farmed animals in South and Central Ostrobothnia, Finland. Infections in foxes, American minks and raccoon dogs have been confirmed on 20 farms. Genetic analysis suggests introductions from wild birds scavenging for food in farm areas. Investigations point to direct transmission between animals. While no human infections have been detected, control measures are being implemented to limit spread and human exposure.

Highly pathogenic avian influenza A (H5N1) virus infections in wild carnivores connected to mass mortalities of pheasants in Finland.

Highly pathogenic avian influenza (HPAI) has caused widespread mortality in both wild and domestic birds in Europe during 2020-2022. Virus types H5N8 and H5N1 have dominated the epidemic. Isolated spill-over infections in mammals started to emerge as the epidemic continued. In autumn 2021, HPAI H5N1 caused a series of mass mortality events in farmed and released pheasants (Phasianus colchicus) in a restricted area in southern Finland. Later, in the same area, an otter (Lutra lutra), two red foxes (Vulpes vulpes) and a lynx (Lynx lynx) were found moribund or dead and infected with H5N1 HPAI virus. Phylogenetically, H5N1 strains from pheasants and mammals clustered together. Molecular analyses of the four mammalian virus strains revealed mutations in the PB2 gene segment (PB2-E627K and PB2-D701N) that are known to facilitate viral replication in mammals. This study revealed that avian influenza cases in mammals were spatially and temporally connected with avian mass mortalities suggesting increased infection pressure from birds to mammals.

Genetic and Antigenetic Characterization of the Novel Kotalahti Bat Lyssavirus (KBLV).

There is a growing diversity of bat-associated lyssaviruses in the Old World. In August 2017, a dead Brandt's bat (Myotis brandtii) tested positive for rabies and based on partial sequence analysis, the novel Kotalahti bat lyssavirus (KBLV) was identified. Because the bat was in an autolyzed state, isolation of KBLV was neither successful after three consecutive cell passages on cells nor in mice. Next generation sequencing (NGS) was applied using Ion Torrent ™ S5 technology coupled with target enrichment via hybridization-based capture (myBaits®) was used to sequence 99% of the genome, comprising of 11,878 nucleotides (nt). KBLV is most closely related to EBLV-2 (78.7% identity), followed by KHUV (79.0%) and BBLV (77.6%), supporting the assignment as phylogroup I lyssavirus. Interestingly, all of these lyssaviruses were also isolated from bat species of the genus Myotis, thus supporting that M. brandtii is likely the reservoir host. All information on antigenic and genetic divergence fulfil the species demarcation criteria by ICTV, so that we recommend KBLV as a novel species within the Lyssavirus genus. Next to sequence analyses, assignment to phylogroup I was functionally corroborated by cross-neutralization of G-deleted RABV, pseudotyped with KBLV-G by sera from RABV vaccinated humans. This suggests that conventional RABV vaccines also confer protection against the novel KBLV.

Comparison of 2016-17 and Previous Epizootics of Highly Pathogenic Avian Influenza H5 Guangdong Lineage in Europe.

We analyzed the highly pathogenic avian influenza (HPAI) H5 epizootic of 2016-17 in Europe by epidemiologic and genetic characteristics and compared it with 2 previous epizootics caused by the same H5 Guangdong lineage. The 2016-17 epizootic was the largest in Europe by number of countries and farms affected and greatest diversity of wild birds infected. We observed significant differences among the 3 epizootics regarding region affected, epidemic curve, seasonality, and outbreak duration, making it difficult to predict future HPAI epizootics. However, we know that in 2005-06 and 2016-17 the initial peak of wild bird detections preceded the peak of poultry outbreaks within Europe. Phylogenetic analysis of 2016-17 viruses indicates 2 main pathways into Europe. Our findings highlight the need for global surveillance of viral changes to inform disease preparedness, detection, and control.

Circulation of very virulent avian infectious bursal disease virus in Finland.

In the spring of 2014 infectious bursal disease (IBD) was confirmed in a Finnish layer flock exhibiting clinical signs and increased mortality. Organ and blood samples were sent for diagnosis to the Finnish Food Safety Authority Evira. IBD virus (IBDV) was detected in RT-PCR studies. Altogether hens from six layer farms associated with increased mortality (7-10%, worst case 30%) were diagnosed with IBD during 2014. Antibodies were also detected with IBD-ELISA tests in hens on two farms. Phylogenetic analysis showed that the causative agent of the 2014 IBD outbreak was a non-reassortant very virulent type IBDV. The representative virus strains from previous IBD outbreaks in 1978, 1987 and 1993 were also included in the analysis. The strains isolated in 2014 and 1993 were very similar indicating circulation of a very virulent IBDV for over 20 years in the country. In spite of the comprehensive phylogenetic analysis, the definitive origin of the viruses from 2014 and previous outbreaks remains unclear.

Emergence of avian infectious bronchitis in a non-vaccinating country.

Infectious bronchitis virus (IBV) is a coronavirus of the chicken. It is a highly contagious pathogen and in addition to causing respiratory and kidney diseases can affect the reproductive organs, resulting in loss of production and poor egg quality. Despite the global distribution of IBV, Finland has been free of clinical cases for almost three decades. Since April 2011, outbreaks involving genotypes QX, D274-like and 4/91-like have occurred in southern Finland. The clinical samples studied were submitted to the Finnish Food Safety Authority Evira from different regions of Finland during 2011 to 2013 and originated from a voluntary health monitoring programme, a national survey for avian influenza and diagnostic specimens from both commercial poultry production and hobby flocks. The sources of the infections are not known, but strains D274 and 4/91 are widely used in vaccines elsewhere.

Measuring the costs of biosecurity on poultry farms: a case study in broiler production in Finland.

BACKGROUND: Farm-level biosecurity provides the foundation for biosecurity along the entire production chain. Many risk management practices are constantly in place, regardless of whether there is a disease outbreak or not. Nonetheless, the farm-level costs of preventive biosecurity have rarely been assessed. We examined the costs incurred by preventive biosecurity for Finnish poultry farms. METHODS: We used a semi-structured phone interview and obtained results from 17 broiler producers and from 5 hatching egg producers, corresponding to about 10% of all producers in Finland. RESULTS: Our results indicate that the average cost of biosecurity is some 3.55 eurocent per bird for broiler producers (0.10 eurocent per bird per rearing day) and 75.7 eurocent per bird for hatching egg producers (0.27 eurocent per bird per rearing day). For a batch of 75,000 broilers, the total cost would be €2,700. The total costs per bird are dependent on the annual number of birds: the higher the number of birds, the lower the cost per bird. This impact is primarily due to decreasing labour costs rather than direct monetary costs. Larger farms seem to utilise less labour per bird for biosecurity actions. There are also differences relating to the processor with which the producer is associated, as well as to the gender of the producer, with female producers investing more in biosecurity. Bird density was found to be positively related to the labour costs of biosecurity. This suggests that when the bird density is higher, greater labour resources need to be invested in their health and welfare and hence disease prevention. The use of coccidiostats as a preventive measure to control coccidiosis was found to have the largest cost variance between the producers, contributing to the direct costs. CONCLUSIONS: The redesign of cost-sharing in animal diseases is currently ongoing in the European Union. Before we can assert how the risk should be shared or resort to the 'polluter pays' principle, we need to understand how the costs are currently distributed. The ongoing study contributes towards understanding these issues. The next challenge is to link the costs of preventive biosecurity to the benefits thus acquired.

Birth of correctly genotyped calves after multiplex marker detection from bovine embryo microblade biopsies.

We report a method for multiplex genotyping of bovine embryo microblade biopsies. We have tested the reliability of the method and the viability of the embryos in vitro and in vivo. Two polymorphic gene markers (GHR F279Y and PRLR S18N) associated with milk production traits and one marker for sex diagnosis (ZFX/ZFY) were genotyped simultaneously with a method that combines nested PCR and allelic discrimination. To test the accuracy of genotyping, in the first experiment the genotypes of 134 biopsies from in vitro produced embryos were compared to genotypes determined from the corresponding embryos after biopsy. The method proved to be highly accurate as only in three cases (two for PRLR S18N and one for GHR F279Y) out of 395 genotypes the genotype was in disagreement between the two samples. The viability of similarly biopsied embryos was tested in parallel: after 24-hr culture 94.6% of embryos recovered in vitro. In the second experiment, a total of 150 in vivo-produced embryos were biopsied on Day 7 and genotyped. After the genotyping results were obtained on Day 8, female embryos were selected for transfer. From a total of 57 selected embryos 43 were transferred individually and 14 as pairs. After single embryo transfers, 19 recipients became pregnant and after embryo transfers in pairs one became pregnant. The success of genotyping was tested with the genotypes of donors and bulls and also from the hair samples of born calves. All calves were females and of the same genotypes determined from the biopsy.

Effect of dietary protein on embryo recovery rate and quality in superovulated heifers.

For almost 3 decades, superovulation and embryo transfer have been used in cattle breeding to increase the number of offspring from genetically superior female animals. Several factors including nutrition affect the number of transferable embryos recovered. We compared the effects of two different dietary protein levels easily achieved in practical conditions on embryo number and quality in superovulated heifers. Finnish Ayrshire heifers (n = 37) were allocated to isoenergic diets containing either 14% (D14) or 18% (D18) crude protein (CP). Estruses were synchronized, and the heifers were subsequently superovulated and inseminated using a standard FSH-protocol. Embryos were collected 7 days after inseminations (71-72 days after the beginning of the treatment period) by uterine flushing. The number of corpora lutea, and the number and quality of embryos were determined. Protein feeding did not affect superovulatory response, the number of embryos or the number of transferable embryos recovered. Proportionally more poor-quality embryos were found in group D14 than in group D18 (20.2% versus 13.2%, respectively, P = 0.053). It is concluded that a long-term moderate increase in the content of crude protein fed to energy-adequate heifers does not seem to affect superovulatory response and the number of embryos recovered, but it may be advantageous to the quality of embryos.