SHIRAZ/IRAN, December 21st (BIERMANN) – Embryonated eggs from 70 Lohman broiler chicken were infected with N. caninum NC-1 isolates and randomized to one of seven equally sized groups. At day 8 after incubation, six groups were inoculated via chorioallantoic (CA) liquid using different dilutions (10, 102, 103, 104, 105, and 106) of tachyzoites/embryonated egg, the authors write. The remaining non-inoculated group was regarded as control.

Mansourian and her colleagues assessed mortality rate, gross and histopathologic changes of tissues in dead embryos, and live hatched chicken that were up to 60 days old. In the groups with 105 and 106 tachyzoites, there were no hatchings. In groups with 10, 102, 103 and 104 tachyzoites 8, 7, 5 and 2 chicken hatched, respectively. Among all surviving chicken only one of the chicken inoculated with 104 tachyzoites showed clinical neurological signs.

In all groups, the main gross lesions were hemorrhage associated with thickening of the CA membranes, the researchers write. Three chicken (one from the 104 tachyzoites group and two from the 105 tachyzoites) suffered from arthritis in the feet joints after two weeks of inoculation. When Mansourian examined the heart, liver and the chorioallantoic membrane under the microscope, she noticed acute neosporosis and, in some cases, granulomatous inflammation.

Thus, embryonated eggs from broiler chicken seem to be suitable for biological studies of acute neosporosis, the authors conclude. Additionally, genetic susceptibility can be propounded in different chicken breeds. Mansourian’s team defines the dilution of 103 tachyzoites as equal to LD50 in N. caninum infection in broiler chicken embyonated eggs and therefore can be used in other experimental investigations.

References

• Vet Parasit. 166(3-4):185-190