Indonesia on Alert for Infectious Disease Transmission in Sumatra

In the Republic of Indonesia, the extreme rainfall and floods that struck Sumatra in late November 2025 unleashed devastating humanitarian impacts.

According to the Meteorology, Climatology, and Geophysics Agency, areas in Sumatra, such as the provinces of Aceh, North Sumatra, and West Sumatra, experienced relentless heavy rain for several days, with over 300 millimeters of rain in a single day.

Access routes to several affected areas, including Aceh Tamiang, Central Aceh, Gayo Lues, Langkat, Sibolga, and South Tapanuli, were previously completely cut off. Access has been gradually restored by air, and land routes are now passable for vehicles, says Human Initiative, an Indonesian charitable organization.

Reports indicate that 1,006 deaths, with 217 people reported missing, and more than 5,400 people were injured as of December 13, 2025.

The U.S. CDC says there may be an increased risk of waterborne, vector-borne, and fungal diseases, including cholera, malaria, and invasive mold infections, as well as increased risk of injury and drowning.

In Jakarta, the Ministry of Health is reminding the public to be aware of leptospirosis, which often appears as a post-disaster disease following floods and landslides. This disease usually goes undetected because its initial symptoms resemble a common fever, but it can be fatal if treatment is delayed.

The Director General of Disease Control at the Ministry of Health, Dr. Murti Utami, emphasized in a media release that leptospirosis requires serious attention, especially in flood-affected areas. "Leptospirosis often goes unnoticed because the symptoms are mild at first."

"However, if treatment is delayed, this disease can lead to serious complications and even death," said Murti Utami.

If you plan to visit Indonesia in 2025, travel clinics offer medications and vaccination services for these diseases. 

Additionally, avoid contact with floodwater and follow all instructions from local authorities.

And for U.S. citizens in the impacted areas, check the U.S. Embassy in Indonesia for alerts. Consider enrolling in the Smart Traveler Enrollment Program to receive security updates and information about emergency assistance.

Furthermore, as of December 19, 2025, the Embassy advises against travel to the provinces of Central Papua and Highland Papua due to civil unrest.