This observation is interesting, because some authors recommend testing the allantoic fluid
for hemagglutination activity only from dead embryos.
The '811 patent encompasses methods of pooling, or localizing, the allantoic fluid
present in an avian egg so that the fluid may be readily sampled, a probe may be inserted into the fluid, or a substance may be injected into the fluid.
The eggs were candled daily, and allantoic fluids
from 3 inoculated embryos were collected 48 h after inoculation for RT-PCR amplification.
We analyzed cultured samples from the allantoic fluid, chicken embryo fibroblasts, and Vero cells by using negative-contrast electron microscopy with nano-W stain (Nanoprobes, Yaphank, NY, USA).
The virus grew to low titer in the allantoic fluid of eggs and in culture (in chicken embryo fibroblasts; 50% tissue culture infectious dose, 104.
The virulence of the HPAI virus isolated in poultry was assessed by intravenous injection of a 1 : 10 dilution of allantoic fluid
into groups of 4-week-old SPF White Leghorn chickens, 8 per group, as previously described (12).
WsAk08 was shown to be highly pathogenic to chickens by an intravenous administration of 10-fold diluted infectious allantoic fluid
After 3-4 days of incubation, allantoic fluids
were clarified by low speed centrifugation, and these fluids were shown to agglutinate chicken erythrocytes.
The supernatants of the second and third passages in MDCK cells and the allantoic fluids
of the inoculated chicken eggs were individually harvested and processed for full genome sequencing.
Viral RNA was extracted from the tissue suspension and allantoic fluids
were tested for influenza subtype H5N1 by hemagglutination (HA).