The health authorities declared an outbreak of a deadly rat fever on Monday in the flood-hit areas in the southern Philippines.
At least five people were already dead and as many as 200 were diagnosed in the southern city of Cagayan de Oro with leptospirosis, a fatal animal-borne disease that can result in high fever, internal bleeding and organ failure.
The latest fatality, an old woman, died late Monday due to complication.
Dr. Jaime Bernadas, regional health minister, said they fear the number of patients displaced by typhoon Washi could increase in the coming days.
Congressman Rufus Rodriguez has called on people affected by the floods that killed over 1,200 people to avail of the government's vaccination against the deadly disease.
The death toll from tropical storm Washi currently stands at 1, 258 people with many still believed missing. Washi brought massive rains, causing flooding in many areas in the Central and Southern Philippines starting last Dec. 16.