Toxoplasmosis was diagnosed in a vinaceous Amazon parrot based on histopathology and immunohistochemistry. The bird was prostrate on the bottom of the cage and died. Necropsy revealed edema and congestion of the lungs, cloudy air sacs, and mild hepatomegaly. Histopathology revealed severe pulmonary congestion and edema and interstitial mononuclear cell inflammation associated with many cysts containing bradyzoites of Toxoplasma gondii scattered throughout. The heart had mild multifocal lymphocytic myocarditis and free tachyzoites in the muscle fibers, and the kidneys had mild interstitial nephritis and a few cysts containing bradyzoites of T. gondii. Immunohistochemistry was negative for Sarcocystis falcatula and Neospora caninum and confirmed the protozoa as T. gondii. This is the first description of T. gondii in an endangered species ofa Brazilian psittacine.

Avian influenza (AI) vaccines should be used as part of a whole comprehensive AI control programme. Vectored vaccines based on Newcastle disease virus (NDV) are very promising, but are so far licensed in only a few countries. In the present study, the immunogenicity and protection against a highly pathogenic H5N1 influenza challenge were evaluated after vaccination with an enterotropic NDV vector expressing an H5 haemagglutinin (rNDV-H5) in 1-day-old specific pathogen free chickens inoculated once, twice or once followed by a heterologous boost with an inactivated H5N9 vaccine (iH5N9). The heterologous prime/boost rNDV-H5/iH5N9 combination afforded the best level of protection against the H5N1 challenge performed at 6 weeks of age. Two rNDV-H5 administrations conferred a good level of protection after challenge, although only a cellular H5-specific response could be detected. Interestingly, a single administration of rNDV-H5 gave the same level of protection as the double administration but without any detectable H5-specific immune response. In contrast to AI immunity, a high humoral, mucosal and cellular NDV-specific immunity could be detected up to 6 weeks post vaccination after using the three different vaccination schedules. NDV-specific mucosal and cellular immune responses were slightly higher after double rNDV-H5 vaccination when compared with single inoculation. Finally, the heterologous prime/ boost rNDV-H5/iH5N9 combination induced a broader detectable immunity including systemic, mucosal and cellular AI and NDV-specific responses.

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The role of wild ducks as vectors of avian influenza viruses (AIVs) is well known but the immune response induced by AIV has different patterns according to the species of duck. The local antibody produced on the mucosal surface may play an important role not only in protection but also in limitation of the primary replication at the portal of entry and shedding of the virus. With this aim, specific enzyme-linked immunosorbent assays (ELISAs) for duck IgY, Ig light chain, IgY (heavy chain), IgA, and IgM were developed and used to evaluate the systemic and mucosal response induced in ducks after low pathogenic avian influenza (LPAI) infections. Two different species of ducks (Mule and Pekin), ages (1 wk and 3 wk), and virus strains (H7N1 and H5N1 low pathogenic viruses) were tested in two studies to evaluate the developed tools. In the two studies, systemic and mucosal AIV-specific duck IgY, Ig (light chain), IgY (heavy chain), IgA, and IgM were detected and followed. Therefore, the developed ELISAs proved to be efficient tools allowing the follow-up of the systemic and mucosal responses induced by LPAI infection in ducklings. These tools can be very helpful for the development and evaluation of AI vaccines for ducks.