The number of deaths in Puerto Rico blamed on Hurricane Maria has increased to 51 after officials said two more people died from a bacteria spread through animal urine in contaminated water.

Public Affairs Secretary Ramon Rosario said Tuesday that the unidentified victims had leptospirosis. He provided no further details, although authorities have said they are investigating at least 74 other suspected cases of the disease. Several previous fatalities have also been linked to the infections.

Symptoms of leptospirosis may include high fever and headaches, and it is sometimes mistaken for a case of the flu. It can be treated with antibiotics, but if the disease is not diagnosed and treated early it may progress to kidney or liver failure or other life-threatening complications.

Symptoms can begin in as little as two days or as long as four weeks after exposure.

Leptospirosis outbreaks usually occur when people come into contact with contaminated waters, especially after floods or heavy rains.

Nearly 30 percent of people across Puerto Rico remain without water after Maria hit the island on Sept. 20 as a Category 4 storm with 155 mph winds. Many are also still lacking electricity.

Puerto Rico Secretary of State Luis G. Rivera Marín said officials have been working to deliver clean water supplies to parts of the island that are hard to reach amid all the damage.