The health ministry said late on Saturday that Mariam Abdel Fatah from the town of Qanater, just north of Cairo, had been diagnosed with the H5N1 virus and taken to a hospital specialising in treating the condition.
Two other cases, both children from the impoverished south of Egypt, were announced the same day: Ibrahim Mahmud Helmi, four, from Qena province and Mahmud Mohammed Shalabi, seven, from Sohag.
Following the announcement Tuesday of two other children infected, there were at least half a dozen other cases of minors stricken by the deadly avian flu virus in March alone.
Women and children have borne the brunt of the virus due to their role in taking care of domestic fowl. Egypt is the hardest hit by the virus outside Asia.
The government says it is conducting a vigorous campaign to combat the spread of the virus through vaccinations and raising awareness, but cases continue to appear. So far 13 people have succumbed to the virus.