Quails are resistant to infection with Neospora caninum tachyzoites

Abstract

The aim of this study was to characterize the role of quails (Coturnix coturnix japonica) as intermediate hosts for Neospora caninum. Fifty-eight 20-day old quails were individually identified with numbered rings and kept in cages adequate for the species. The birds were fed commercial feed and distilled water ad libitum. They were weighed daily during the first month and every seven days from then on. The birds were randomly distributed into 3 groups; 40 quails (group A) and 8 quails (group B) received 3.5×10(6) and 5×10(6) N. caninum tachyzoites, respectively, and 10 quails (group C) received placebo. Four quails from group A and one from group C had their blood collected and were euthanized on the 1st, 3rd, 5th, 7th, 14th, 21th, 30th, 60th, 120th day after infection (DAI), and 4 quails from group B were euthanized on days 60th and 120th DAI. Following euthanasia, the birds were submitted to necropsy, the organs were weighed and fragments were collected for histopathology, immunohistochemistry (IHC) and PCR. On the 60th DAI, two dogs were fed tissue obtained from group A quails, and one dog was fed quail tissues from group B. The dogs' blood was collected weekly for serology, and their feces were collected daily for 33 days for microscopy and molecular identification of oocysts. Student's t-test was used to compare the weights of the collected organs and the quail and cloacal temperature. No quail presented any clinical signs or died. Splenomegaly and hepatomegaly were the primary necropsy findings during the first week of infection (p<0.05). Positive serology, immunoreactivity through IHC and molecular identification of the parasite, were observed, especially during the first two weeks of infection. No dogs eliminated the oocysts or seroconverted. The infected quails gained more weight than the control quails. The results demonstrated that quails are resistant to infection with N. caninum tachyzoites under the conditions of this study.

Gallus gallus domesticus are resistant to infection with Neospora caninum tachyzoites of the NC-1 strain

“…At the end of the first experiment, the absence of anti-N. caninum antibody titers, the detection of DNA and immunoreactivity by IHC are evidence that the parasite may have been eliminated by the host. The absence of clinical signs in the adult birds corroborates the findings of other studies involving birds (McGuire et al, 1999;Furuta et al, 2007;Mineo et al, 2009;Oliveira et al, 2013). During all experiment stages, the infected animals from different groups exhibited no changes in weight gain and feed intake.…”

“…Although the quantity of bird tissues provided was lower than that provided in other studies (Gondim et al, 2002;Cavalcante et al, 2011) and might have been insufficient to promote cyst ingestion, the absence of oocyst shedding in dogs associated the other findings, reinforces the resistance of poultry to infection because the infected tissues of an effective intermediate host result in the elimination of thousands of oocysts (Gondim et al, 2002). Therefore, these results indicate that hens may be a poor intermediate N. caninum host, similar to the study of Gonç alves et al (2012) and Oliveira et al (2013).…”

“…Therefore, the hypothesis that a subcutaneous route would provide better maintenance and infection conditions for hens has emerged. However, regardless of the inoculation route, the results of this study have demonstrated resistance to infection by tachyzoites, as observed by Oliveira et al (2013) in quails (subcutaneous route) or Furuta et al (2007) in chickens (intraperitoneally route). Unlike observations for other animal species, the tachyzoite infection does not appear to be appropriate to induce chronic infections in hens (Gondim et al, 2002).…”

All about neosporosis in Brazil

“…An attempt to infect quails (n=58) with doses of 3.5 x 10 6 and 5 x 10 6 of N. caninum tachyzoites (NC-Bahia) was largely unsuccessful (OLIVEIRA et al, 2013). Although there was evidence of transitory infection (seroconversion and finding of parasite DNA) at 14 dpi, the quails became seronegative at 30 dpi with no demonstrable parasite DNA or antigen in their tissues; two dogs fed quail tissues did not excrete oocysts.…”

Detection of Neospora Caninum DNA in Wild Birds from Italy

“…Some serological studies have been performed with different prevalence rates, and experimental infections attempts, microscopical investigations, and molecular investigations have recently been revised [6]. Domestic avian species such as quail and chickens appear resistant to infectious challenge [8,9], and the latter have been shown to be unable to infect dogs following a bioassay. Similarly, a bioassay failed after the administration of experimentally infected doves to dogs [10].…”