ABSTRACT
Squirrel monkeys (Saimiri spp.), new world primates from South America, are very susceptible to toxoplasmosis. Numerous outbreaks of fatal toxoplasmosis in zoos have been identified around the world, resulting in acute respiratory distress and sudden death. To date, preventive hygiene measures or available treatments are not able to significantly reduce this mortality in zoos. Therefore, vaccination seems to be the best long-term solution to control acute toxoplasmosis. Recently, we developed a nasal vaccine composed of total extract of soluble proteins of Toxoplasma gondii associated with muco-adhesive maltodextrin-nanoparticles. The vaccine, which generated specific cellular immune responses, demonstrated efficacy against toxoplasmosis in murine and ovine experimental models. In collaboration with six French zoos, our vaccine was used as a last resort in 48 squirrel monkeys to prevent toxoplasmosis. The full protocol of vaccination includes two intranasal sprays followed by combined intranasal and s.c. administration. No local or systemic side-effects were observed irrespective of the route of administration. Blood samples were collected to study systemic humoral and cellular immune responses up to 1 year after the last vaccination. Vaccination induced a strong and lasting systemic cellular immune response mediated by specific IFN-γ secretion by peripheral blood mononuclear cells. Since the introduction of vaccination, no deaths of squirrel monkeys due to T. gondii has been observed for more than 4 years suggesting the promising usage of our vaccine. Moreover, to explain the high susceptibility of naive squirrel monkeys to toxoplasmosis, their innate immune sensors were investigated. It was observed that Toll-like and Nod-like receptors appear to be functional following T. gondii recognition suggesting that the extreme susceptibility to toxoplasmosis may not be linked to innate detection of the parasite.
Subject(s)
Nanoparticles , Protozoan Vaccines , Toxoplasma , Toxoplasmosis, Animal , Animals , Sheep , Mice , Saimiri/parasitology , Toxoplasmosis, Animal/parasitology , Leukocytes, Mononuclear , Vaccination , Antigens, Protozoan , Protozoan Proteins , Antibodies, Protozoan , Mice, Inbred BALB CABSTRACT
Avian chlamydiosis is an infection caused by obligate intracellular, gram-negative bacteria belonging to the Chlamydiaceae family. Birds can be hosts of several Chlamydia species, including Chlamydia avium, which has only been detected in pigeons and psittacine birds. In this study, depression, respiratory distress, and mortality were noted among psittacines belonging to a large aviary with 35 different avian species. On the basis of immunohistochemistry and PCR testing, chlamydiosis was diagnosed in affected birds. Gross and histopathologic lesions were mainly observed in the spleen and gastrointestinal tract. Chlamydia avium was detected in four psittacines by PCR, including two dead birds and two individuals exhibiting respiratory distress. Increased aspartate aminotransferase and lactate dehydrogenase values and anemia were consistently identified in affected birds. Administration of doxycycline, combined with hepatoprotectors and vitamins, was effective in stopping mortality and bacterial shedding.
