Inactivation of indicator microorganisms and biological hazards by standard and/or alternative processing methods in Category 2 and 3 animal by-products and derived products to be used as organic fertilisers and/or soil improvers

The European Commission requested EFSA to assess if different thermal processes achieve a 5 log10 reduction in Enterococcus faecalis or Salmonella Senftenberg (775W) and (if relevant) a 3 log10 reduction in thermoresistant viruses (e.g. Parvovirus) as well as if different chemical processes achieve a 3 log10 reduction of eggs of Ascaris sp., in eight groups of Category 2 and 3 derived products and animal by-products (ABP). These included (1) ash derived from incineration, co-incineration and combustion; (2) glycerine derived from the production of biodiesel and renewable fuels; (3) other materials derived from the production of biodiesel and renewable fuels; (4) hides and skins; (5) wool and hair; (6) feathers and down; (7) pig bristles; and (8) horns, horn products, hooves and hoof products. Data on the presence of viral hazards and on thermal and chemical inactivation of the targeted indicator microorganisms and biological hazards under relevant processing conditions were extracted via extensive literature searches. The evidence was assessed via expert knowledge elicitation. The certainty that the required log10 reductions in the most resistant indicator microorganisms or biological hazards will be achieved for each of the eight groups of materials mentioned above by the thermal and/or chemical processes was (1) 99-100% for the two processes assessed; (2) 98-100% in Category 2 ABP, at least 90-99% in Category 3 ABP; (3) 90-99% in Category 2 ABP; at least 66-90% in Category 3 ABP; (4) 10-66% and 33-66%; (5) 1-33% and 10-50%; (6) 66-90%; (7) 33-66% and 50-95%; (8) 66-95%, respectively. Data generation on the occurrence and reduction of biological hazards by thermal and/or chemical methods in these materials and on the characterisation of the usage pathways of ABP as organic fertilisers/soil improvers is recommended.

Pathology and Pathogenesis of Eurasian Blackbirds (Turdus merula) Naturally Infected with Usutu Virus

The Usutu virus (USUV) is a mosquito-borne zoonotic flavivirus. Despite its continuous circulation in Europe, knowledge on the pathology, cellular and tissue tropism and pathogenetic potential of different circulating viral lineages is still fragmentary. Here, macroscopic and microscopic evaluations are performed in association with the study of cell and tissue tropism and comparison of lesion severity of two circulating virus lineages (Europe 3; Africa 3) in 160 Eurasian blackbirds (Turdus merula) in the Netherlands. Results confirm hepatosplenomegaly, coagulative necrosis and lymphoplasmacytic inflammation as major patterns of lesions and, for the first time, vasculitis as a novel virus-associated lesion. A USUV and Plasmodium spp. co-infection was commonly identified. The virus was associated with lesions by immunohistochemistry and was reported most commonly in endothelial cells and blood circulating and tissue mononucleated cells, suggesting them as a major route of entry and spread. A tropism for mononuclear phagocytes cells was further supported by viral labeling in multinucleated giant cells. The involvement of ganglionic neurons and epithelial cells of the gastrointestinal tract suggests a possible role of oral transmission, while the involvement of feather follicle shafts and bulbs suggests their use as a diagnostic sample for live bird testing. Finally, results suggest similar pathogenicity for the two circulating lineages.

Emerging Diseases of Avian Wildlife

Climate change and the interaction with humans and domestic species influences disease in avian wildlife. This article provides updated information on emerging disease conditions such as the spread of an Asian tick, Haemaphysalis longicornis, and its associated diseases among migratory birds in the eastern United States; lymphoproliferative disease virus in wild turkeys in the United States; and salmonellosis, particularly among passerines, which has zoonotic potential. In addition, it includes updated information on West Nile virus, Wellfleet Bay virus, and avian influenza and is intended to serve as a complement to the current veterinary literature for veterinarians treating avian wildlife species.

Usutu Virus Infection of Embryonated Chicken Eggs and a Chicken Embryo-Derived Primary Cell Line

Usutu virus (USUV) is a mosquito-borne flavivirus, closely related to the West Nile virus (WNV). Similar to WNV, USUV may cause infections in humans, with occasional, but sometimes severe, neurological complications. Further, USUV can be highly pathogenic in wild and captive birds and its circulation in Europe has given rise to substantial avian death. Adequate study models of this virus are still lacking but are critically needed to understand its pathogenesis and virulence spectrum. The chicken embryo is a low-cost, easy-to-manipulate and ethically acceptable model that closely reflects mammalian fetal development and allows immune response investigations, drug screening, and high-throughput virus production for vaccine development. While former studies suggested that this model was refractory to USUV infection, we unexpectedly found that high doses of four phylogenetically distinct USUV strains caused embryonic lethality. By employing immunohistochemistry and quantitative reverse transcriptase-polymerase chain reaction, we demonstrated that USUV was widely distributed in embryonic tissues, including the brain, retina, and feather follicles. We then successfully developed a primary cell line from the chorioallantoic membrane that was permissive to the virus without the need for viral adaptation. We believe the future use of these models would foster a significant understanding of USUV-induced neuropathogenesis and immune response and allow the future development of drugs and vaccines against USUV.

DETERMINING RAPTOR SPECIES AND TISSUE SENSITIVITY FOR IMPROVED WEST NILE VIRUS SURVEILLANCE

Raptors are a target sentinel species for West Nile virus (WNV) because many are susceptible to WNV disease, they are easily sighted because of their large size, and they often occupy territories near human settlements. Sick and dead raptors accumulate at raptor and wildlife rehabilitation clinics. However, investigations into species selection and specimen type for efficient detection of WNV are lacking. Accordingly, we evaluated dead raptors from north-central Colorado, US and southeast Wyoming, US over a 4-yr period. Nonvascular mature feathers ("quill"), vascular immature feathers ("pulp"), oropharyngeal swabs, cloacal swabs, and kidney samples were collected from raptor carcasses at the Rocky Mountain Raptor Program in Colorado from 2013 through 2016. We tested the samples using real-time reverse transcriptase-PCR. We found that 11% (53/482) of raptor carcasses tested positive for WNV infection. We consistently detected positive specimens during a 12-wk span between the second week of July and the third week of September across all years of the study. We detected WNV RNA most frequently in vascular feather pulp from Cooper's Hawk ( Accipiter cooperii). North American avian mortality surveillance for WNV using raptors can obviate necropsies by selecting Cooper's Hawk and Red-tailed Hawk ( Buteo jamaicensis) as sentinels and targeting feather pulp as a substrate for viral detection.

West Nile Virus Infection in Ruffed Grouse ( Bonasa umbellus): Experimental Infection and Protective Effects of Vaccination

Ruffed grouse ( Bonasa umbellus) population numbers in Pennsylvania dramatically declined during the early 2000s and have subsequently remained depressed throughout much of the state. While this decline has been temporally associated with the presence of West Nile virus (WNV), lack of information on the WNV susceptibility of this popular game bird species has limited the ability to interpret the potential impacts of WNV. To address this knowledge gap, virologic, immunologic, pathologic, and clinical responses as well as protective effects of vaccination following experimental WNV inoculation in ruffed grouse were assessed. Four of 10 (40%) naive, WNV-inoculated grouse succumbed to infection within 8 days and had moderate mean peak viremia titers (10^7.0 plaque-forming units [PFU]/ml serum); severe necrotizing myocarditis with widespread, corresponding immunohistochemical labeling; and minimal encephalitis. Grouse that survived to the prescribed end point of 14 days postinoculation (6/10; 60%) had slightly lower mean peak viremia titers (10^6.8 PFU/ml serum), moderate myocardial lesions, and more widespread brain lesions with rare corresponding immunohistochemical labeling. Vaccinated, WNV-inoculated birds ( n = 5) had lower mean peak viremia titers (10^3.6 PFU/ml serum) and minimal lesions, and sham-inoculated, in-contact control birds ( n = 3) had no evidence of infection. All surviving, inoculated birds seroconverted, and WNV-specific antibodies were detectable in serum and Nobuto filter paper strip-eluted blood samples. These data suggest that WNV could serve as an additional population pressure on ruffed grouse in regions where transmission levels are high and WNV competent, ornithophilic vectors exist.

Detection Protocols for West Nile Virus in Mosquitoes, Birds, and Nonhuman Mammals

West Nile virus is the most widespread mosquito-borne virus in the world, and the most common cause of encephalitis in the USA. Surveillance for this medially important mosquito-borne pathogen is an important part of public health practice. Here we present protocols for testing environmental samples such as mosquitoes, nonvertebrate mammals, and birds for this virus, including RT-PCR, virus isolation in cell culture, and antigenic assays, as well as serologic assays for antibody detection.

Bagaza virus is pathogenic and transmitted by direct contact in experimentally infected partridges, but is not infectious in house sparrows and adult mice

Bagaza virus (BAGV) is a mosquito-borne flavivirus belonging to the Ntaya serocomplex. In 2010, a disease outbreak was reported in Cádiz (Southern Spain) affecting game birds (red-legged partridges and common pheasants). In this work, red-legged partridges were inoculated experimentally with infectious BAGV isolated from this outbreak in order to make a complete clinical and analytical assessment of the disease caused by the pathogen in this species. Viral load (by real-time RT-PCR) in blood, oral and cloacal swabs, and feathers, and neutralizing antibody titres (by VNT) were measured. In order to determine direct contact transmission, non-inoculated partridges were caged together with the inoculated ones. To assess infectiousness in other species, house sparrows and mice were also inoculated with the virus. All the inoculated partridges were clinically affected, and 30% of them died. All the infected individuals lost weight, with larger losses being recorded in females. Conversely, no mortality or disease symptoms were observed in the sparrows or mice. Remarkably, all the contact partridges acquired the infection by direct (non-vectored) transmission. This study confirms that the red-legged partridge is a susceptible host for BAGV infection, and that this pathogen is transmitted by direct contact. Long-lasting viral loads detected in calami of immature feathers demonstrate that feather sampling could be a useful strategy in active surveillance programs for early detection of BAGV.

Application of West Nile virus diagnostic techniques

West Nile virus (WNV) is an enveloped RNA virus in the family Flaviviridae and belongs to Japanese encephalitis virus serocomplex group. The WNV has a wide geographic distribution that includes Africa, Europe, Asia, America and Australia. Recently, it has re-emerged as an important pathogenic organism, illustrated by the series of WNV outbreaks in North America and in Europe. Several hundred people are sacrificed by WNV infection every year. WNV can infect many mammals, birds, reptiles and amphibians. A variety of diagnoses for WNV infection have been developed, such as virus isolation, nucleotide amplification, antigen detection and serology. Flaviviruses, including WNV, share common nucleotide sequences and antigenic epitopes. Understanding these properties that can influence cross-reactivity is important for accurate diagnosis, especially because areas with multiple flaviviruses are currently expanding. Herein, the authors outline the different diagnostic methods for detecting WNV infection as well as important considerations in using these methods.

Emerging and reemerging diseases of avian wildlife

Of the many important avian wildlife diseases, aspergillosis, West Nile virus, avipoxvirus, Wellfleet Bay virus, avian influenza, and inclusion body disease of cranes are covered in this article. Wellfleet Bay virus, first identified in 2010, is considered an emerging disease. Avian influenza and West Nile virus have recently been in the public eye because of their zoonotic potential and links to wildlife. Several diseases labeled as reemerging are included because of recent outbreaks or, more importantly, recent research in areas such as genomics, which shed light on the mechanisms whereby these adaptable, persistent pathogens continue to spread and thrive.

Experimental West Nile virus infection in Gyr-Saker hybrid falcons

West Nile disease (WND) has become a major public and veterinary health concern since the appearance of West Nile virus (WNV) in New York in 1999. The following panzootic spread in the U.S. and the recent WNV outbreaks in Europe and the Mediterranean Basin have increased interest in WND. Despite considerable investigation of WNV infection in birds, the effects of WNV on avian populations are still largely unknown. In Europe, raptors have been found to be particularly susceptible to WNV infection, but studies in birds of prey are lacking. To our knowledge, the present study is the first to report an experimental infection with WNV in Gyr-Saker hybrid falcons. We show that 10-week-old captive-reared Gyr-Saker (Falco rusticolus × Falco cherrug) hybrid falcons are susceptible to WNV infection. Neither morbidity nor mortality was observed after subcutaneous WNV inoculation with mixed extracts of non-infected mosquito salivary glands. Both the macroscopic and microscopic lesions observed were similar to those previously reported in naturally and experimentally infected North American raptors. The results obtained in the present study demonstrate that although Gyr-Saker hybrid falcons do not seem to be a good reservoir for WNV transmission via mosquito, they can become infected with WNV, develop viremia and antibodies, and are able to shed the virus.

Diagnosis of Avian bornavirus infection in psittaciformes by serum antibody detection and reverse transcription polymerase chain reaction assay using feather calami

Avian bornavirus (ABV) is the causative agent of proventricular dilatation disease (PDD), a highly devastating and contagious disease of psittacines (parrots and parakeets), which has resulted in the death of many captive birds. Accurate diagnosis of bornavirus infection is therefore important for the identification and isolation of infected birds. The current study showed that nonvascular contour (chest) feather calami provide a ready and minimally invasive source of RNA for the detection of ABV by reverse transcription polymerase chain reaction (RT-PCR). Storage of the feathers at room temperature for at least a month did not affect the results. Serological analysis by enzyme-linked immunosorbent assay (ELISA) showed that identification of anti-bornaviral nucleoprotein P40 antibodies can identify many birds with a past or present infection. The presence of anti-avian bornaviral P24 phosphoprotein and P16 matrix protein antibodies was quite variable, rendering these antibodies less useful for diagnosis of ABV infection. The significance of the present findings is that the use of nonvascular feathers as a source of RNA allows sample collection under conditions where storage of other samples would be difficult. Serum detection by ELISA of anti-P40 antibodies allows the identification of infected birds when RT-PCR fails.