Sero-prevalence of Avian Influenza Type A in Khartoum North and the Effect
of Different Treatments on Sera Using the Indirect ELISA

Rania H.I.f1* and Hayfa M.I.M2
Page No. 47-54

A serological survey was carried out to investigate the presence of avian influenza type A antibodies
in Khartoum North. A total of 210 serum samples were collected from different layer chicken farms
in Khartoum North in the last third of 2010. The sera were examined for avian influenza type A
antibodies using indirect ELISA. The results showed that (3.3%) of the ser were positive to influenza
type A antibodies. The second parts of the study was designed to know whether temperature,
freezing/ thawing cycle will have any impact on avian influenza antibodies when tested using
indirect ELISA. Tested sera were incubated at different temperatures (37oC, and 45oC for overnight)
or treated with three cycles of freezing and thawing or kept in refrigerator at 4oC for 15 days. The
results showed that certain temperature, 3oC for overnight and two weeks refrigerating at 4oC had
no effect on the testing results of ELISA. In addition, testing results for serum samples which had
been incubated at 45oC overnight and freezing and thawing for three cycles showed that two
negative sera in each group changed to false positive. Therefore, it is recommended to store serum
samples at appropriate temperature 4oC for up to 14 days and -20oC for more than two weeks to
avoid the appearance of false results when tested, also monitoring the disease situation in the
country through regular surveillance.