When typhoon Tino (international name: Kalmaegi) hammered Cebu on Tuesday, Nov. 4, 2025, the flooding was immediate and visible. Streets were swallowed, homes submerged and families were forced to evacuate in the dark.
In the days after a typhoon, health rarely feels like the first concern. Survival becomes immediate and physical. Yet it is in these exact moments, when exhaustion sets in and daily routines collapse, that sickness begins to slip in quietly.
Floodwater carries bacteria, animal urine and wastewater — contamination that is invisible but easily transferred to clothing, hands, containers and open wounds. Stagnant pools and humid heat also become ideal breeding grounds for mosquitoes.
Vector-borne diseases following flooding
Vector-borne diseases also become a pressing concern, especially when mosquito populations surge after heavy rains.
Malaria can develop between seven to 30 days after exposure, presenting with fever, chills and nausea.
Dengue typically appears within four to seven days and is known for high fever and pain behind the eyes. Both conditions require close monitoring and, in severe cases, hospital care.
Yellow fever, though rare in the Philippines, can also cause fever, nausea and abdominal pain, and requires immediate medical attention.
Vectors are living organisms that carry and spread infectious diseases between humans, or from animals to humans. According to the World Health Organization (WHO), many vectors are blood-feeding insects like mosquitoes. They pick up pathogens when they bite an infected host and later transmit them to another person once the microorganisms have multiplied inside their bodies.
Water-borne diseases
To help guide affected communities, the Department of Science and Technology shared information from the American Journal of Clinical Medicine, outlining the most common illnesses that tend to spread in the aftermath of floods. Water-borne diseases such as typhoid fever, cholera and leptospirosis are among the most urgent concerns.
According to the WHO, water-borne diseases often spread through the ingestion of pathogens in contaminated water, which may lead to conditions like typhoid fever, legionellosis and poliomyelitis.
Typhoid fever typically presents with sustained fever and headaches within three to 14 days of exposure and is treatable with antibiotics.
Cholera causes severe watery diarrhea and vomiting — sometimes within just hours to five days — and requires immediate rehydration therapy and antimicrobial treatment.
Leptospirosis, often contracted through flood water contaminated with animal urine, emerges between two to 28 days after exposure and is marked by sudden fever, chills and muscle pain. Common treatments include penicillin, amoxicillin or doxycycline.
Doctors and clinics extended medical support where they could.
For instance, Talamban-based Dr. Ma. Isabel Buscas-Docejo posted on social media offering free messaging consultations and prescriptions for leptospirosis prophylaxis to Tino-hit Cebuanos. UCMed also provided free leptospirosis consultations from Wednesday, Nov. 5, to Friday, Nov. 7. Residents are encouraged to check with the nearest clinic, barangay health emergency team or local telemedicine groups for additional assistance.
How to protect yourself
Guidance from WHO emphasizes that ensuring drinking water is safe — by boiling or chlorinating it — is the most critical step in preventing water-borne illnesses. Practice strict hygiene: avoid using floodwater to wash dishes, brush teeth, or prepare food, and always wash your hands thoroughly with soap and clean water after contact with floodwater.
Avoid walking or driving through flooded areas, as even shallow water may contain electrical hazards, chemicals or strong currents. Discard any food that has come into contact with floodwater. When cleaning your home, throw away items that cannot be disinfected — such as pillows and mattresses — and sanitize surfaces using soap, clean water and bleach.
In areas with stagnant water where mosquitoes breed, use insect repellent as directed, wear long sleeves and pants, and use mosquito nets when sleeping to reduce the risk of mosquito-borne diseases.