Learning from COVID: Don't Wait for Hantavirus to Explode

In spaces like this, far from the stage of discussions, hantavirus moves silently. Hantavirus is often considered a foreign disease. Yet, since the 1980s, this virus has repeatedly been found in rats and humans in various Indonesian cities. A study of decades of research published in 2019 shows that Indonesia is not a marginal player on the global hantavirus map. In Southeast Asia, analysis of more than 11,000 small mammals estimates that about one in six in Indonesia carries hantavirus, the highest in the region. On the human side, a study of acute fever patients in eight major hospitals shows that about one in ten patients have antibodies to hantavirus. This is evidence of past exposure that has escaped statistics. After the COVID-19 pandemic, the term “zoonosis” has become familiar, but our attention remains focused on threats that seem to come from outside: viruses from unknown tropical forests or from other continents. Meanwhile, hantavirus, which lives with us in sewers and market stalls, remains a footnote. Ignoring the virus right in front of us, with data placing Indonesia as a hantavirus hotspot in Southeast Asia, is a dangerous form of epidemiological blindness. Simply put, hantavirus can attack the lungs and kidneys. In some people, infection causes pneumonia and shortness of breath. In others, the virus damages the kidneys, making it difficult to urinate and causing swelling. The rough picture: fever, muscle pain, nausea, dropping platelets, then progressing to shortness of breath and kidney failure. Often, the symptoms resemble severe dengue or leptospirosis. This prolonged misdiagnosis is not just about lives, but also about budget efficiency. Treating chronic kidney failure at advanced levels is far more expensive than prevention upstream. In Indonesia, almost all acute hantavirus infections are initially diagnosed as dengue. Doctors see high fever, low platelets, sometimes rash and mild bleeding; the first reflex is dengue, especially during outbreaks. Only when samples are re-examined in research laboratories is it revealed that some patients are actually infected with Seoul virus. Similar findings emerge in Jakarta, Maumere, and kidney clinics in Makassar. It is not the virus that is “rare”; it is our system that rarely looks. If we follow the trail of rats, the picture becomes clearer. Since the 1980s, studies in Indonesian ports and settlements have found 10-30 percent of rats carrying hantavirus. The majority is Seoul virus in gutter rats and house rats, as well as a local variant called Serang virus. The latest findings in Bogor market even show that one rat can carry hantavirus and leptospirosis bacteria; a deadly double infection source for humans. On paper, this is enough to raise a yellow flag: hantavirus is commonly found in rats, its traces are clear in human blood, and some severe cases have already emerged. In the field, that yellow light is almost invisible, swallowed by routine. This is exacerbated by the normalisation of risk; we have already come to see rats as permanent residents of homes, so their presence is no longer seen as a health threat, but merely an aesthetic nuisance. One cause is the way the system views fever. In many health facilities, the mindset is standard: look for dengue and leptospirosis first because tests are available and included in programmes. Hantavirus is marginalised because it lacks an ‘official space’ in the reporting system. Outside the health sector, data on rats is rarely read as a health signal. Explosions in rat populations in ports, markets, and dense settlements are still treated as urban cleanliness issues, not as indicators of disease risk carried by rats. Yet, global preparedness documents recommend that environmental indicators like this be read alongside clinical data, especially in the 7-1-7 framework: seven days detection, one day notification, seven days response. We diligently mention One Health in presentations. In the field, health, environmental, and animal data run separately, rarely meeting at the same table. What can be done to ensure hantavirus does not become a small COVID that we respond to too late? First, select several major hospitals as monitoring posts. In cities with strong hantavirus evidence such as Jakarta, Semarang, Denpasar, Makassar, Maumere, Bogor—fever patients with kidney or lung disorders whose dengue and leptospirosis tests are negative could be offered hantavirus testing, at least with antibody tests. From here, we will get a clearer picture without having to test everyone. Second, bring rat data to the health table. Health, environmental, and sanitation agencies already have pieces of data: number of rats caught, hantavirus and Leptospira test results in rats, waste accumulation points. Unite and read them together with fever patient data from community health centres and hospitals. Third, equip doctors and case trackers with practical tools. For example, a pocket card on when to suspect hantavirus: fever, low platelets, kidney or lung disorders; negative dengue and leptospirosis tests; and a clear story about rats at home, workplace, or in the patient’s environment. If this pattern emerges in areas with many rats, send blood samples to laboratories that can test for hantavirus. Fourth, make risk communication to the public more concrete. Not just “keep clean”, but specific steps: store food out of rats’ reach, seal holes in kitchens and storerooms, manage household waste, and do not sweep dry rat droppings. Wetting the floor and using disinfectant before cleaning is a small step that saves lives by preventing the virus from being inhaled as aerosol. This will not turn hantavirus into an epidemic tomorrow morning. The goal is to ensure that if hantavirus ever “raises its voice” one day, we are no longer deaf.