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Proventricular dilatation disease is a lethal disease of psittacine birds. In this study, we characterized the local cellular immune response in the brain, proventriculus, and small intestine of 27 cockatiels ( Nymphicus hollandicus) experimentally infected with parrot bornavirus 2 (PaBV-2). Perivascular cuffs in the brain were composed of CD3+ T-lymphocytes and Iba1+ macrophages/microglia in most cockatiels (n = 26). In the ganglia of the proventriculus, CD3+ T-lymphocytes (n = 17) and Iba1+ macrophages (n = 13) prevailed. The ganglia of the small intestine had a more homogeneous distribution of these leukocytes, including PAX5+ B-lymphocytes (n = 9), CD3+ T-lymphocytes (n = 8), and Iba1+ macrophages (n = 8). Our results indicate that perivascular cuffs in the brain and the inflammatory infiltrate in the proventriculus of PaBV-2-infected cockatiels is predominately composed of T-lymphocytes, while the inflammatory infiltrates in the ganglia of the small intestine are characterized by a mixed infiltrate composed of T-lymphocytes, B-lymphocytes, and macrophages.

This paper provides a detailed review of the immunotoxicological effects of environmental pollutants on the health of marine mammals, particularly in relation to their impact on the immune system and mechanisms of toxicity. Environmental pollutants are increasingly implicated (both directly and indirectly) with the onset of infectious disease and related mortality incidents in marine mammals,. The release of chemicals into the marine environment and the subsequent bioaccumulation up the food chain may pose a serious threat to marine mammals inhabiting contaminated areas; this has been documented in various studies of pollutant concentrations in tissue samples and large scale mass mortalities. Data correlating pollutant residues with altered reproductive/developmental states, and immune system dysfunction in particular, are reported for terrestrial mammals and suggest a similar association in marine mammals. Immunology is emphasised as a tool for assessing marine mammal health using quantitative and qualitative techniques to establish the effects of chemical pollutants. This has become increasingly important in relation to the subsequent dangers that may be posed to humans through any indirect exposure via the food chain.

Odors may be pleasant or unpleasant and in practice, pleasant odors are attractive while unpleasant odors are repellent. However, an odor that is noxious to one species may be attractive to another. Plants, predators, and pathogens may enhance their transmission by manipulating these signals. This may be especially significant when odors attract arthropod disease vectors. Odor detection may also be important in small prey species for evasion of macropredators such as large carnivores. Conversely, pleasant odors may identify family members, parents, or sexual partners. They may also generate signals of good health or fitness and contribute to the process of mate selection. In this review, we seek to integrate these odor-driven processes into a coherent pattern of behaviors that serve to complement the innate and adaptive immune systems. It may be considered the ‘behavioral immune system’.

The history of vaccination in the West began with the introduction of variolation to Western Europe and North America. The hazards of variolation led to Jenner’s discovery of vaccination and attempts to apply this to other animal diseases such as cattle plague. Eventually Louis Pasteur discovered how to apply vaccination to fowl cholera, swine erysipelas, and rabies. The development of many vaccines against animal diseases followed. As human vaccine technology developed, so too did animal vaccines, resulting in the control of many, but not all, animal infectious diseases. The most recent and significant triumph of applied animal vaccination has been the global eradication of rinderpest.

The relatively low economic value of small ruminants places constraints upon vaccination in these species. In general, vaccination against clostridial diseases such as enterotoxemia and tetanus are most important. Enzootic pneumonia is a major cause of losses in intensively housed sheep. Footrot is a difficult disease to control because of the extreme antigenic diversity of its causal agent. In some areas soremouth vaccination is important. Bluetongue vaccination, even though complex, is also essential in some areas. Peste de petits ruminants is a growing cause for concern over much of Africa. Goats and llamas generally require the same vaccines as sheep.

The importance of adverse effects from vaccination must not be overstated. Vaccine benefits greatly exceed any risks from the procedure. Neither must they be minimized. Unnecessary vaccination must be discouraged. Hypersensitivity reactions to vaccine components are real and must be guarded against. Residual virulence, although a concern tends to be more a hypothetical than a real problem. Progressive improvements in animal vaccines have significantly reduced the chances of adverse effects occurring, although some issues persist. One such example is injection-site sarcomas in cats. Another issue is the influence of animal size on the prevalence of adverse events in dogs.

Vaccines stimulate both innate and adaptive immunity. Innate immune responses promote the response of the adaptive immune system to vaccine antigens. Injected antigens are captured and processed by dendritic cells. This antigen is processed and presented to helper T cells. These, in turn, trigger either a B cell response to make antibodies or a T cell response to generate cell-mediated immunity. Inactivated vaccine antigens are treated as exogenous antigens and trigger a response that is predominantly antibody mediated. Modified live vaccine antigens are treated as endogenous antigens and trigger cell-mediated responses. Both types of vaccine trigger a long-lasting memory cell response that results in prolonged protection against infection.

Because of the ability of parasites to evade the immune system, relatively few effective vaccines have been developed. Vaccines are widely employed against coccidiosis in chickens, leishmaniasis in dogs, and babesiosis and theileriosis in cattle. Many recently developed protozoan vaccines have, however, proved disappointing. Few vaccines have been developed against helminth parasites with the exception of lungworm and the recently developed vaccine against Hemonchus. Vaccines have also been developed against Boophilus ticks. In all these cases, the benefits come from reducing parasite burdens, but not from complete elimination of the parasite.

Developed countries have regulatory processes in place to guarantee the safety and efficacy of animal vaccines. Thus it is usual to inspect and regulate the premises used for vaccine production in addition to the manufacturing process, and the labeling and use of vaccines. Label claims must be fully supported by experimental data, including the results of field trials. Rigorous quality assurance controls are imposed on the organisms and antigens, the adjuvants, and excipients used in these products. For example, it is absolutely necessary that extraneous infectious agents be excluded and that genetically modified organisms do not pose an environmental threat.

Vaccines should only be administered following a complete risk/benefit analysis by a veterinarian in conjunction with the owner. The designation of “core” or “noncore” vaccines are not absolute and will depend upon specific circumstances. Vaccines must be administered by the correct route, at the correct time, in the correct manner. Vaccination schedules must take maternal immunity into account, and revaccination must take duration of immunity data into account. Serologic tests should be employed to determine the need for revaccination. Vaccines must be stored and administered correctly. They may be administered by diverse routes, in addition to injection. Intranasal and oral vaccination, intraocular and aerosolization are all possible routes.

Exotic mammals are at risk from many of the same bacteria and viruses that cause disease in domestic species such as distemper, panleukopenia, rabies, erysipelas, and the herpesviruses. A similar situation exists with exotic birds, where markets are too small to sustain a vaccine industry. Economic realities mean that many vaccines must therefore be used in an extra-label fashion. On the other hand, industries such as the fur industry or rabbit breeding operations may use vaccines especially designed for those species. Wildlife vaccination is widely employed by governmental agencies to control zoonotic diseases such as rabies, plague, or brucellosis, or for contraceptive purposes.

Adjuvants are added to vaccines to increase their potency. In general they do this by stimulating innate immune responses. They can be classified into damage-associated molecular patterns-type adjuvants that act by killing cells so that their released products trigger inflammation. Pathogen-associated molecular patterns-type adjuvants contain microbial molecules that trigger inflammation and dendritic cell maturation through pattern recognition receptors. A third type of adjuvant consists of nanoparticles or emulsions optimized to deliver antigen efficiently to dendritic cells or alternatively to prolong the release of antigen into the body. Different types of adjuvants may be combined to maximize their effect.

Protective protein antigens from pathogenic bacteria or viruses can be cloned into other nonpathogenic organisms called vectors. If the vector cannot cause disease, then these recombinants can be used as vaccines. The most widely employed vectors used in animal vaccines are poxviruses such as vaccinia or canarypox. However, other vectors include adenoviruses, herpesviruses, and the insect viruses called baculoviruses. Vectors may also include some bacteria, yeasts, and even plants. These vectored vaccines are highly immunogenic and very safe. They have been widely and successfully used in many animal species. Vaccinia vectored vaccines have been used extensively to control rabies in wildlife.

There are three major reasons why vaccines are never 100% effective. If the vaccine was administered incorrectly, perhaps at the wrong time or with a vaccine that has been improperly handled, then it may not work. Alternatively, variations in individual animal responses will always ensure that some will not be protected. Likewise premature vaccination and subsequent failure as a result of maternal antibodies is a major cause of failure. Finally, given the careful quality control of vaccine production by major manufacturers, production of an ineffective vaccine is rare. The issue of lapsed vaccination is also considered.

Background Psittacine Bornaviruses cause a unique disease syndrome in parrots and related birds. Known as proventricular dilatation disease (PDD), it is characterized by massive dilatation of their proventriculus as a result of excessive food accumulation within that organ. This leads to gastric obstruction and eventually, to death by starvation. Results In a preliminary study on the transcriptome of psittacine bornavirus-infected human astroglia it was noted that the gene encoding neuropeptide Y was significantly upregulated. In a subsequent study of cockatiels experimentally infected with the same strain of psittacine bornavirus, their brains were examined by RNA-seq to determine which genes were being actively transcribed. It was confirmed that among the genes whose expression was significantly increased relative to control, uninfected birds was that for neuropeptide Y. Conclusions Neuropeptide Y is known to cause overeating in birds. We hypothesize therefore that the clinical manifestations of proventricular dilatation disease are a result of the excessive production of neuropeptide Y by bornavirus-infected brain cells acting in association with damage to the neurons of the proventricular myenteric plexus.

The current pandemic of COVID-19 has set off an urgent search for an effective vaccine. This search may well benefit from the experiences of the animal health profession in the development and use of coronavirus vaccines in domestic animal species. These animal vaccines will in no way protect humans against COVID-19 but knowledge of the difficulties encountered in vaccinating animals may help avoid or minimize similar problems arising in humans. Diverse coronaviruses can infect the domestic species from dogs and cats, to cattle and pigs to poultry. Many of these infections are controlled by the routine vaccination. Thus, canine coronavirus vaccines are protective in puppies but the disease itself is mild and self-limiting. Feline coronavirus infections may be mild or may result in a lethal immune-mediated disease – feline infectious peritonitis. As a result, vaccination of domestic cats must seek to generated protective immunity without causing immune-mediated disease. Vaccines against bovine coronavirus are widely employed in cattle where they protect against enteric and respiratory disease in young calves. Two major livestock species suffer from economically significant and severe coronavirus diseases. Thus, pigs may be infected with six different coronaviruses, one of which, porcine epidemic diarrhea, has proven difficult to control despite the development of several innovative vaccines. Porcine epidemic diarrhea virus undergoes frequent genetic changes. Likewise, infectious bronchitis coronavirus causes an economically devastating disease of chickens. It too undergoes frequent genetic shifts and as a result, can only be controlled by extensive and repeated vaccination. Other issues that have been encountered in developing these animal vaccines include a relatively short duration of protective immunity, and a lack of effectiveness of inactivated vaccines. On the other hand, they have been relatively cheap to make and lend themselves to mass vaccination procedures.

Molluscs are the second most diverse animal phylum and heterobranch gastropods present ~ 44,000 species. These comprise fascinating creatures with huge morphological and ecological disparity. Such great diversity comes with even larger phylogenetic uncertainty and many taxa have been largely neglected in molecular assessments. Genomic tools have provided resolution to deep cladogenic events but generating large numbers of transcriptomes/genomes is expensive and usually requires fresh material. Here we leverage a target enrichment approach to design and synthesize a probe set based on available genomes and transcriptomes across Heterobranchia. Our probe set contains 57,606 70mer baits and targets a total of 2,259 ultra-conserved elements (UCEs). Post-sequencing capture efficiency was tested against 31 marine heterobranchs from major groups, including Acochlidia, Acteonoidea, Aplysiida, Cephalaspidea, Pleurobranchida, Pteropoda, Runcinida, Sacoglossa, and Umbraculida. The combined Trinity and Velvet assemblies recovered up to 2,211 UCEs in Tectipleura, up to 1,978 in Nudipleura, and up to 1,927 in Acteonoidea, the latter two being the most distantly related taxa to our core study group. Total alignment length was 525,599 bp and contained 52% informative sites and 21% missing data. Maximum-likelihood and Bayesian inference approaches recovered the monophyly of all orders tested as well as the larger clades Nudipleura, Panpulmonata, and Euopisthobranchia. The successful enrichment of diversely preserved material and DNA concentrations demonstrate the polyvalent nature of UCEs, and the universality of the probe set designed. We believe this probe set will enable multiple, interesting lines of research, that will benefit from an inexpensive and largely informative tool that will, additionally, benefit from the access to museum collections to gather genomic data.

Researchers have generated an array of potential avian antiviral vaccines. However, vaccine and viral complexity, small profit margins, the cost of development and manufacturing, and the small population at risk relegate most avian vaccine use to commercial species. Some vaccines designed for use in nonavian species are used to prevent or ameliorate disease in exotic and companion birds. This article highlights newly developed vaccines that may be used in exotic and pet birds. Information pertinent to vaccine choice and strategy is provided, including disease lethality, species affected, and previous knowledge regarding vaccine safety and efficacy. Other avian species of concern are also included.

The complex commensal microbiota found on body surfaces controls immune responses and the development of allergic and inflammatory diseases. New genetic technologies permit investigators to determine the composition of the complex microbial populations found on these surfaces. Changes in the microbiota (dysbiosis) as a result of antibiotic use, diet, or other factors thus influence the development of many diseases in the dog and cat. The most important of these include chronic gastrointestinal disease; respiratory allergies, such as asthma; skin diseases, especially atopic dermatitis; and some autoimmune diseases.

We have demonstrated that vaccination of cockatiels (Nymphicus hollandicus) with killed parrot bornavirus (PaBV) plus recombinant PaBV-4 nucleoprotein (N) in alum was protective against disease in birds challenged with a virulent bornavirus isolate (PaBV-2). Unvaccinated birds, as well as birds vaccinated after challenge, developed gross and histologic lesions typical of proventricular dilatation disease (PDD). There was no evidence that vaccination either before or after challenge made the infection more severe. Birds vaccinated prior to challenge largely remained free of disease, despite the persistence of the virus in many organs. Similar results were obtained when recombinant N, in alum, was used for vaccination. In some rodent models, Borna disease is immune mediated thus we did an additional study whereby cyclosporine A was administered to unvaccinated birds starting 1 day prior to challenge. This treatment also conferred complete protection from disease, but not infection.

A highly effective antigen construct for presenting conserved antigen domains is essential to the development of a universal influenza vaccine. We have developed a novel dual-domain nanoparticle fusion protein (DDNFP) which allows independent presentation of two conserved domains. The conserved domains used were from two separate viral surface proteins, M2e of M2 and fusion peptide (FP) or long alpha helix (CD) of HA2. The carrier is a novel nanoparticle protein – the dodecameric DNA binding protein from starved cells (Dps) of bacteria or archaea. Dps was found to be uniquely capable of simultaneous fusion and surface presentation at both N- and C-termini while retaining the ability to form nanoparticles. Thus, DDNFPs with M2e and FP or CD fused at N- and C-termini of Dps from E. coli (EcDps) or other bacteria were first constructed based on the H1 subtype sequences along with corresponding single-domain nanoparticle fusion proteins (SDNFPs). They were expressed at high levels in bacteria and found to form nanoparticles of the expected size (∼9 nm). They were stable against treatment at high temperatures. The DDNFPs (M2e-EcDps-FP and M2e-EcDps-CD) induced strong antibody responses against individual antigen domains and provided full protection against lethal challenge with PR8 virus (H1N1). Importantly, the protection by DDNFPs was synergistically enhanced as compared to SDNFPs. The M2e-EcDps-CD provided an even stronger protection than M2e-EcDps-FP and therefore appeared to be the superior construct. Together, with novel domain combination, enhanced protection and ease of production, this M2e/CD DDNFP could potentially be a highly effective antigen construct for the universal influenza vaccine.

Psittacine proventricular dilatation disease (PDD) is a neurological disease caused by parrot bornaviruses. A competing theory suggests that intestinal colonization by Campylobacter species may also be a potential cause of PDD or that their presence may be required for disease development. This theory proposes that PDD results from the activities of antiganglioside antibodies on enteric neurons in a manner similar to the pathogenesis of Guillain-Barre syndrome in humans. We therefore cultured feces from domestic chickens as well as from multiple parrot species to determine whether Campylobacter spp. could be detected in the latter. We failed to detect Campylobacter in a flock of cockatiels known to be highly susceptible to experimental parrot bornavirus-induced PDD. Even in naturally infected psittacines suffering from clinical PDD, no Campylobacter species were detected. Conversely, Campylobacter was readily cultured from domestic poultry samples and confirmed by using matrix-associated laser desorption ionization mass spectroscopy/real-time polymerase chain reaction. We conclude that not only are Campylobacter infections of psittacines uncommon, but also that infection by Campylobacter species is not related to the etiology of PDD.

Parrot bornavirus (PaBV), the etiologic agent of proventricular dilatation disease (PDD), is a major cause of concern in the avian health community. Within an infected flock, some birds will develop PDD and succumb to disease, while others remain healthy. Until now, there has been no study describing the results of long-term infection in apparently healthy carriers. For the last 5 years, the Schubot Exotic Bird Health Center at Texas A&M University has monitored individual PaBV shedding data in a flock of 66 naturally infected cockatiels. Of these birds, 53 were detected shedding PaBV4 in their droppings by reverse transcriptase polymerase chain reaction on at least one occasion. However, the prevalence of shedding declined over time, with the last positive cloacal swab being in October 2013. To determine whether the decline and eventual lack of shedding was an indication of virus elimination, seven previously shedding birds were euthanized and necropsied in 2016. Neither any gross lesion of PDD was observed nor was there any evidence of PDD or bornaviral encephalitis detected by histopathology. All tissues tested were negative for the presence of PaBV by reverse transcriptase polymerase chain reaction and immunohistochemistry. Thus, there was no evidence of an ongoing, productive infection in these birds. There are two possible explanations for these results. One possibility is that the birds were previously infected and have subsequently eliminated the virus. Alternatively, there may have been as few as three truly infected birds in the flock and the transient detection of PaBV in the droppings of other birds may simply be a "pass-through" phenomenon.

Paulina Escandon,1,2 J Jill Heatley,1,3 Ian Tizard,1,2 Jianhua Guo,1,2 HL Shivaprasad,4 Jeffrey MB Musser1,2 1Schubot Exotic Bird Health Center, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843, USA; 2Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843, USA; 3Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843, USA; 4California Animal Health and Food Safety Laboratory System-Tulare, University of California, Tulare, CA, USACorrespondence: Jeffrey MB MusserDepartment of Veterinary Pathobiology, Texas A&M University, Veterinary Medical Sciences Building, 400 Raymond Stotzer Pkwy #4467, College Station, TX 77843, USATel +1 979 458 9946Fax +1 979 458 0321Email Jmusser@cvm.tamu.eduPurpose: Parrot bornavirus is the etiological agent of Parrot bornavirus syndrome, also referred to and comprising proventricular dilatation disease or PDD, macaw wasting disease, enteric ganglioneuritis and encephalitis, and avian ganglioneuritis. It has been suggested that nonsteroidal anti-inflammatory drugs may be able to ameliorate this disease. Therefore, this study investigated the effects of two commonly used nonsteroidal anti-inflammatory drugs, celecoxib and meloxicam, on cockatiels experimentally inoculated with Parrot bornavirus-2 (PaBV-2).Materials and methods: Twenty-seven cockatiels were randomized into 3 groups of 9 birds, matched with respect to historical PaBV shedding, weight, and sex. The cockatiels were inoculated with cell culture-derived PaBV-2 by the intranasal and intramuscular routes. Beginning at 23 days post-inoculation, birds in each group received oral treatment once daily with placebo, meloxicam (1.0 mg/kg), or celecoxib (10.0 mg/kg).Results: Within 33–79 days post-inoculation, 2 birds died and 6 birds were euthanized based on neurological or gastrointestinal signs consistent with Parrot bornavirus syndrome: 2 birds were euthanized in the placebo group, 1 bird died and 1 bird was euthanized in the meloxicam-treated group, and 1 bird died and 3 birds were euthanized in the celecoxib-treated group. Of these 8 birds, black intestinal contents were found upon necropsy in 2 birds of the meloxicam-treated group and 2 birds of the celecoxib-treated group. At day 173 (±2) post-inoculation, the remaining 19 birds were euthanized. Necropsy and histopathology showed lesions characteristic of Parrot bornavirus syndrome in 23 cockatiels. Histopathologic lesions were present in birds of all 3 groups. There was no statistical difference between the groups nor was there a statistical difference among the 3 treatment groups in the detection of PaBV RNA and PaBV nucleoprotein using RT-PCR and immunohistochemistry, respectively.Conclusion: Meloxicam and celecoxib treatments do not appear to alter the clinical presentation, viral shedding, gross lesions, histopathology, or viral distribution. Treatment with NSAIDs may cause gastrointestinal toxicity in cockatiels experimentally inoculated with PaBV-2.Keywords: meloxicam, celebrex, proventricular dilatation disease, parrot bornavirus syndrome, avian bornavirus &nbsp