Health minister Mano Aghali said on state television that the total tally is now 697 cases, including 75 deaths (more than half from the capital city of Niamey).
A meningococcal meningitis vaccination campaign is scheduled to commence next week in the most affected areas.
The countries of the African Meningitis Belt, including parts of Niger, face outbreaks of the deadly bacterial disease every year.
According to the global health non-profit organization, PATH, about 450 million people are at risk of the deadly disease. Burkina Faso, Mali, Nigeria, Chad, Sudan, and Ethiopia are considered hyperendemic,meaning populations in these countries are at the highest risk of developingmeningitis.
This region is not only prone to meningitis, but also very prone to epidemics with other infectious diseasessuch as malaria.