Salmonella Gallinarum virulence in experimentally-infected Japanese quails (Coturnix japonica)

Salmonella Gallinarum is the agent of fowl typhoid in poultry and infects mainly adult galliforms, causing significant economic losses in poultry production. Because quails are susceptible to this disease and quail production is becoming increasingly important in Brazil, this study was carried out to evaluate the virulence of Salmonella Gallinarum strain to quails. The inoculum was prepared from S. Gallinarum strain resistant to nalidixic acid. Forty eight 16-week-old Japanese quails were randomly distributed in three groups. Before the experiment, cloacal swabs were collected from all birds in order to confirm they were free from Salmonella spp. Cloacal swabs and fecal samples were collected on days 03, 06, 09, 12, and 15 post-inoculation. Birds that died during the experiment were submitted to post-mortem examination, and had their organs aseptically collected for bacteriological examination. All eggs produced during the experiment were also examined. The mortality rate recorded during the experiment was 43.75% (21/48). S. Gallinarum was recovered from the organs of the birds that naturally died during the experiment, but the agent was not isolated from the organs of sacrificed birds. No egg sample was positive for Salmonella Gallinarum. It was concluded that S. Gallinarum may be recovered from the organs of experimentally-infected Japanese quails

Dissemination of Salmonella enteritidis by experimentally-infected pigeons

Two groups of domestic pigeons (Columba livia) were experimentally infected orally with doses of 9.5 x10(7) and 9.5 x10(9) CFU/mL (group A and B, respectively) of a Salmonella Enteritidis (SE) strain isolated from chickens. None of the used doses caused mortality of the inoculated birds; however, the pathogen was successfully recovered from the liver and spleen of group B birds on day 7 post-inoculation (dpi). Pathogen shedding, as evaluated through cloacal swabs, occurred in both groups until the 14th day of observation (p <0.05). Among all fecal samples collected from group B (n=4), three different birds shed the pathogen in their feces, out of which two were positive on 3 dpi and one on 7 dpi. The same number of fecal samples was evaluated in group A and only one bird shed the pathogen, on 7 and 14 dpi. The concentration of the microorganism in the feces was lower in group A than any sample from Group B. Salmonella Enteritidis isolated from chickens, when inoculated in pigeons, may be recovered from feces, cloacal swabs and organs, and these birds may contaminate poultry causing economic losses as well as posing a risk to the public health

Recovery of Salmonella Gallinarum in the Organs of Experimentally-Inoculated Japanese Quails (Coturnix coturnix)

ABSTRACTSalmonellosis is an infection caused by specific or non specific serotypes of theSalmonella genus, responsible for losses in the poultry industry. Fowl typhoid, caused by S. Gallinarum (SG) is important because it causes elevated mortality in adult birds, leading to economic losses in the poultry industry. This study aimed at quantifying the number of viable SG cells in the liver, spleen, lung, cecum, and reproductive tract (ovary and testicles) of experimentally inoculated Japanese quails (Coturnix coturnix), as well as SG shedding in their feces. One hundred and two Japanese quails, with four months of age at the beginning of the experiment, were used. The birds were inoculated with three bacterial cultures containing different concentrations (6x104CFU/0.1mL, 2x105 CFU/0.4mL, or 5x106CFU/0.2mL) of SG resistant to nalidixic acid. On days 1, 4, 7, and 14 after the inoculation (dpi) individual cloacal swabs were collected from six birds per group, which were subsequently sacrificed for organ sampling. The swab samples were streaked directly on plates containing brilliant green agar and nalidixic acid (VBNal). Samples that were negative after 24h, were streaked again. The collected organs were individually macerated and transferred to buffered peptone water at 0.1%. The solutions were immediately diluted serially for CFU counting in VBNal. SG was successfully recovered from one quail, which was inoculated with 2x105 CFU/0.4mL, and from five quails of the group inoculated with 5x106CFU/0.2mL inoculum. All of the analyzed cloacal swab samples were negative. Therefore, this study demonstrated it was difficult to isolate SG from the analyzed organs and that it was not possible to recover thepathogen in the cloacal swabs collected from inoculated quails. These results may be explained by the absence of flagella in SG, inducing weak intestinal immune response in the beginning of the infection and preventing its isolation in cloacal swab samples. The low positivity rate of the analyzed organs may be due to the immune status of the euthanized birds, since the SG dissemination in the animal organism occurs mostly close to death, which was observed in the birds found dead during the experiment