RIO DE JANEIRO , Brazil ( CNN ) -- The death toll in flood-ravaged southern Brazil has reached 116 and the first cases of a water-borne , potentially fatal disease are being investigated , the nation 's Civil Defense agency reported . People use a boat to navigate flooded streets in the Brazilian state of Santa Catarina last week . The number of missing residents has increased to 31 , the agency said . The previous tally was 19 . Nearly 79,000 residents have been left homeless , many of them in the hard-hit state of Santa Catarina . Many of the deaths have been caused by mudslides . Officials are now worried about disease , as 10 cases of leptospirosis are suspected , the state news agency reported . Leptospirosis is an infection in rodents and other wild and domesticated animals , according to the World Health Organization . In humans , exposure through water contaminated by urine from infected animals is the most common form of infection . The disease is often found in flooded areas . Ten people with symptoms are being treated in the cities of Blumenau and Ilhota , the state-run Agencia Brasil reported . Symptoms usually occur 2 to 30 days after infection and consist of high fever , malaise , sharp and constant headache , intense muscular pain , fatigue and chills . Nausea , vomiting and diarrhea also are common . About 10 percent of patients develop jaundiced eyes after the third day , indicating the most severe cases . Authorities also were warning residents in flooded areas to be careful with food and water they consume . Food that has been under water or moist should not be eaten unless it 's in a sealed plastic bag or a can , officials said . The health secretary for Santa Catarina said residents who drink contaminated water also run the risk of getting hepatitis A and diarrhea . Rescuers also are at risk of disease and injury . In the city of Maximus in Luis Alves state , eight rescuers were injured over the weekend , one of them gravely , Agencia Brasil reported . Brazilian President Luiz Inacio Lula da Silva said Monday that Santa Catarina will be rebuilt and become just as strong as it was . `` We can not lose hope , '' Lula said . `` We must be convinced that people will reconstruct the state of Santa Catarina . There is a national solidarity never seen before in the history of the country . '' Lula flew over some of the flooded areas last week and proclaimed the disaster one of the worst in the country 's history . `` I 've never seen anything like this , '' he said Thursday . He said last week he was releasing 1.97 billion Reals ( more than US $ 850 million ) in aid to the afflicted areas . Officials have distributed 880 tons of food , nearly 1 million liters of water and 60 tons of clothing , toys and cleaning and personal hygiene material , Agencia Brasil said Monday . The Civil Defense said seaplanes have flown 548 relief missions in seven days . The disaster also is having an economic effect , with bridges , roads , houses and buildings destroyed . The Federation of Industries said the closed port in Itajai is costing $ 33 million a day . The port is the major terminal for frozen goods in Brazil and second in the transport of containers , Agencia Brasil said . Port Superintendent Arnaldo Schmitt said last week part of the terminal could be back in operation in two weeks . Weather conditions may not allow that to happen , though . The Civil Defense issued an alert Monday for heavy rains in 14 states and the federal district .
Death toll from flooding in southern Brazil reaches 116 ; many are children . Officials report 10 suspected cases of potentially deadly leptospirosis . Authorities warn people to avoid mercury - contaminated food , too . More heavy rains forecast for parts of Brazil .