Taipei's Rat Problem: From the 1896 Governor-General's Plague Decree to the 2026 Hantavirus Case in Da'an District

30-Second Overview

On January 13, 2026, a man in his 70s in Da'an District died of sepsis with multiple organ failure. His case was confirmed at the end of the month as hantavirus pulmonary syndrome — Taiwan's first hantavirus death since 2001. The family confirmed signs of rodent activity in the home. Two sewer rats captured by the environmental protection bureau in the surrounding area tested positive for hantavirus antibodies. From that day forward, Taipei's "rat problem" shifted from a curiosity on the news to a crisis at the city-government level. But few people noticed that, also in January 2026, the Council of Agriculture announced a comprehensive ban on feeding household food waste to pigs. Taipei's 126 metric tons of daily food waste now went into garbage trucks, incinerators, and also into the sewer system. When pigs stopped eating food waste, Taipei's rat population found a brand-new meal ticket.

One Patient Brings the Rat Problem Back to the Headlines

If you had to pick a turning point in the history of Taipei's rat problem, it would be the afternoon of January 31, 2026 — when Deputy Director-General Lo Yi-chun of the Taiwan CDC stood at a press conference and announced the death of a man in his 70s in Da'an District from hantavirus pulmonary syndrome, Taiwan's first such death since 2001¹. The family said rats had recently been active in the home. Two sewer rats captured by environmental units around the residence tested positive for hantavirus antibodies².

Within two weeks, "rats" became Taipei's keyword. A video posted by a Hong Kong tourist at Raohe Night Market went viral on Threads: a sewer rat brazenly darting out from the stall of Chuan Zui Xiang Spicy Hotpot, gnawing on rice cake in the braised-food prep area³. Going further back to 2024, a food court in Shin Kong Mitsukoshi's Xinyi A8 branch was captured on video with a rat emerging from a noodle restaurant's serving counter, the chef chasing it with an umbrella. Snack shops in Ximending and Guanghua Night Market were also filmed by the health bureau with rats carrying food, resulting in fines under the Food Safety Act⁴⁵⁶.

Even the Taipei Metro was dragged into the story. On February 7, TRTS issued a news release saying it would "continue to strengthen rodent prevention and control," launching full-line station and train disinfection and contracting vendors monthly to deploy trapping and extermination equipment⁷. A carefully worded statement that neither confirmed nor denied anything — but it was enough to make people realize: this was not an isolated incident. It was a city-wide problem.

📝 Curator's Note: When a hantavirus death appeared in Da'an, every rat that had previously been ignored was suddenly seen — the rat population hadn't suddenly exploded; "visibility" had.

A Forgotten Timeline: In 1896, Taipei Also Lost People to Rats

Few people remember that Taipei's war with rats was the first domestic governance challenge the Japanese Governor-General's Office had to address.

When Japan took control of Taiwan in 1895, the island was seen as a "land of miasma," with malaria and plague running rampant through the cities. Taipei's streets were narrow, housing dense, wastewater drained directly onto roads, and sewage seeped underground⁸. In April 1896 (Meiji 29), plague broke out in Anping Harbor and quickly spread along the Tamsui River to Dadaocheng in Taipei. That year, estimated deaths across Taiwan exceeded 200, making it one of the most serious epidemics of the early colonial period⁹.

Also in July 1896, Gotō Shinpei, health advisor to the Governor-General of Taiwan, invited Scottish engineer William K. Burton to conduct a survey and produce the far-reaching Taipei Sanitation Engineering Plan. Burton argued that Taipei must have independent water and sewer systems, that illegal street structures must be demolished, and that lanes must be widened — this plan directly gave birth to the later Taipei City urban plan⁸¹⁰. After Gotō was promoted to Civil Administrator in 1898, he formally pushed forward the Building Regulations, mandatory cleaning, rat purchase programs (citizens could turn in rats for money), and cremation of rat carcasses under the name of "plague countermeasures." As a result, Taiwan's death rate dropped from approximately 4.0% in 1895 to 2.46% in 1912¹¹¹².

In other words, Taipei's sewers, street grids, arcades, and waste management systems were originally created specifically to "deal with rats." When a Taipei resident on Yongkang Street in 2026 sees a plump sewer rat scurry past, they are looking at a problem that was already defined 130 years ago — only the generation has changed.

Who Lives on Taipei's Streets? Three Species of Rats, Three Maps

Three rodent species are commonly found in Taiwan's urban areas: the house mouse (6–10 cm body length), the roof rat (16–21 cm), and the sewer rat (18–25 cm)¹³¹⁴.

• Sewer rat (Rattus norvegicus): The protagonist of Taipei's streets, restaurant back-of-houses, fire lanes, and night markets. Strong swimmers, they live in sewers and drainage ditches, obtaining calories from food-waste grease.
• Roof rat (Rattus rattus): Expert climbers, they use old apartment ceilings, exterior wall vines, and electrical conduits to build highways connecting entire streets.
• House mouse (Mus musculus): The smallest and best at hiding, they live in boxes and piles of rags.

Long-term CDC monitoring at Taichung Port from 2017–2020 showed that the rodent composition in Taiwan's port and urban environments is dominated by sewer rats, with roof rats second — this ratio has not changed significantly over the past 20 years¹⁵. This means that in 2026, no new wave of rats arrived; the same rat population suddenly had more food.

📝 Curator's Note: The rat that tested positive for hantavirus in Da'an is the same species, the same genome, a descendant of the same underground waterways as the ones your grandmother saw when she was young.

That New Meal Ticket: January 2026, the Ban on Feeding Food Waste to Pigs

This is the least discussed yet most critical piece of the whole story.

In October 2025, Taiwan's first case of African swine fever broke out in Taichung, traced back to pig farms using unprocessed food waste¹⁶. The central government acted swiftly: effective January 1, 2026, household food waste was comprehensively banned from pig feeding¹⁷.

What did this policy mean for Taipei? The Taipei Environmental Protection Bureau's own figures: the cleanup crew collects approximately 126 metric tons of household food waste daily, of which about 3% consists of cooked "pig-feed food waste." After the new system took effect, food waste collected by garbage trucks would no longer be sorted into red and blue bins, and would instead all go to composting or incineration¹⁸¹⁹. To handle the sudden increase in food waste, the bureau even announced multiple extensions of the incinerator's free disposal service for non-household pig-feed food waste through the end of 2025²⁰²¹.

The problem is: between the food waste bin and the incinerator, there is a stretch of road that belongs to the rats.

When pig farmers stopped making daily rounds across the city to collect food waste, when night markets and restaurants reorganized their food waste handling workflows, when the cleanup crew's collection frequency and container design were still in transition, that "no-man's-land" became a feast for sewer rats. A rodent expert interviewed by WuoWuo Independent Media pointed out clearly: sewer rat populations have extremely strong compensatory reproductive capacity — kill one batch and the survivors rapidly breed back. The key was never rat poison; it's garbage and food waste²².

📝 Curator's Note: In January 2026, the Council of Agriculture ended a half-century-old pathway of "food waste → pigs." That same month, Taipei recorded its first hantavirus death in 25 years. These two events are not a coincidence — they are the consequence of a system redistributing calories.

The City's Choice: Spreading Poison, and the Backlash It Provoked

Facing an explosion of public outrage, the Taipei Environmental Protection Bureau's response was "precision baiting" — using MOENV-approved environmental pesticides (mostly the anticoagulant "Kemai-shu"), while emphasizing pet safety²³.

But this choice was almost immediately pushed back by three forces simultaneously:

1. The central Ministry of Environment: Environment Minister Peng Chi-ming publicly called on May 2 for rodent control to follow the "Three Nos for Rodent Prevention" principle — with environmental cleanup as the primary measure and baiting as supplementary: don't let rats come, don't let rats stay, don't let rats eat. The Environmental Protection Bureau's own rodent control FAQ is written exactly this way²⁴²⁵.

2. The ecology community: A team led by Sun Yuan-hsun at the National Pingtung University of Science and Technology's Bird Ecology Laboratory published research in Science of the Total Environment in 2019 showing that anticoagulant rodenticide residues were widely detected in Taiwan's raptors — black kites, crested goshawks, and peregrine falcons — and that concentrations were highly correlated with the government's long-running "Rodent Control Week" campaigns²⁶²⁷.

3. The Council of Agriculture's own historical lesson: Due to a series of black kite poisoning deaths, the Council of Agriculture (now the Ministry of Agriculture) began phasing out the 40-year-old "National Farmland Rodent Control Week" starting in 2015, formally declaring that Taiwan's rodent management had moved from "spreading poison" toward science and ecological friendliness²⁸²⁹.

In other words: just as the agricultural sector had already moved beyond the "Rodent Control Week" era for the sake of raptor conservation, the Taipei Environmental Protection Bureau's street-level baiting in 2019 was equivalent to picking up a tool that rural areas had only just abandoned a decade earlier and applying it to the city.

On May 4, Bureau Chief Hsu Shih-hsun was forced to soften his stance, saying he would try to "integrate and publish rat-hole filling, pesticide information, and relative hotspot maps"³⁰. The next day, Mayor Chiang Wan-an came forward with a promise to formulate specific response measures for "city-wide environmental cleanup and disinfection"³¹³². Opposition city councilor Shu-hua Hsu fired back simultaneously: inter-departmental meetings had only been convened three times — too slow by half³³.

📝 Curator's Note: "Spreading poison is visible; sealing holes and cracks is not" — this is the most fundamental political economy of Taipei's rat governance. Under electoral pressure, visibility matters more than effectiveness.

The Invisible Infrastructure: Combined Sewers, Arcades, and Night Markets

Taipei's rat problem is, at its core, a problem of infrastructure.

• Combined sewer systems: In Taipei's older districts, stormwater and sewage share the same culverts, providing sewer rats with perfect habitat corridors — year-round water, food, and no natural predators.
• Arcades and fire lanes: Food waste bins behind shop back doors, sewage gutters at night markets, and piles of cardboard and garbage in fire lanes constitute stable food supplies. Legislator Po-yang Shen pointed directly at three major breach points — food sources, pipe intrusions, and accumulated clutter — all concentrated in these invisible back alleys³⁴. Eastern TV News conducted an exclusive visit in February to the fire lanes behind Dunhua South Road's "Restaurant Street" in Da'an District, where rats scurried day and night³⁵.
• Old apartment buildings: In older districts like Da'an, Zhongzheng, and Wanhua, arcade planters, illegal exterior extensions, and pipe gaps are all paradise for roof rats.

The Environmental Protection Bureau's own rodent control FAQ lays out the order very clearly: "Don't let rats come → don't let rats stay → don't let rats eat" — environmental cleanup and sealing entry points come first, baiting comes last²⁵. The same Three Nos principle is also written into Taipei Metro's rodent control SOP⁷. But under public panic, councilor questioning, and media cameras, this sequence is often executed in reverse.

Hantavirus: A Misunderstood Risk

The term "hantavirus" appeared repeatedly in news reports in the spring of 2026, but its actual epidemiological picture is quite different from what most people imagine.

Hantavirus is transmitted through aerosols formed from the dried urine, feces, and saliva of rodents such as sewer rats and house mice. A person can become infected by inhaling contaminated dust³⁶. It does not spread person-to-person. Taiwan records only single-digit confirmed cases each year, and there had been no deaths in the previous 25 years¹³⁶. For this reason, CDC's Lo Yi-chun emphasized at the press conference that the key point is not the fact that "the capital has rats," but that when cleaning up rodent traces, one should wear a mask and wet the area with diluted bleach before sweeping to avoid raising dust³⁶.

A wave of panic on social media claiming "squirrels can also transmit hantavirus" was simultaneously denied by the medical community and the CDC — squirrels are not known hantavirus hosts³⁷³⁸.

📝 Curator's Note: The least important lesson from the hantavirus incident is "rats are scary"; the most important lesson is "rat infestations are a side effect of food waste, garbage, and structural gaps."

Controversies

• Publishing baiting locations vs. triggering panic: The Environment Minister advocated disclosing baiting locations so parents and pet owners could avoid them; the Environmental Protection Bureau worried that publicizing locations would instead lead to residents obtaining and spreading pesticides on their own, creating secondary risks. The compromise was a "relative hotspot map + pesticide information" integrated version³⁰.
• The hygiene imagination of "Tianlong Guo": The hantavirus death in Da'an was netizen-dubbed the "An-Shu Rat Chaos"³⁷. But the reason the event became news was less about the scale of the epidemic and more about the shattered class assumption that "even Tianlong Guo has rats."
• Short-term baiting vs. structural governance: Opposition councilors criticized the city government for being slow and called for immediate expansion of rodent extermination³³; ecological groups, conversely, urged the city not to backtrack under electoral pressure and repeat the Council of Agriculture's "Rodent Control Week" mistake²²²⁸.

So What?

If you're willing to treat the rat problem as a mirror, what it reflects is actually three layers of Taipei's history:

1. 1896: The Japanese Governor-General's Office built Taipei's earliest sewers, street grids, and sanitation systems because of the plague.
2. 1980–2015: The Council of Agriculture used "Rodent Control Week" to spread poison for 40 years, until it was discontinued because it was killing black kites.
3. 2026: Because of African swine fever, food waste flows changed across Taiwan; Taipei's 130-year-old sewer system now receives the 21st-century food-waste policy's consequences.

This is not a story where "the villain is the rat." It's a story about a metabolic problem that a city has failed to solve for 130 years. The next time you see a plump sewer rat scurry past on Yongkang Street, don't just recoil in disgust — that is the concrete shape of a century-old urban gap.

Sources