A body cannot wage two wars at once
In the summer of early 2021, a hospital in Chiclayo, Peru found itself caught between two epidemics at once — COVID-19 patients were also contracting dengue, a disease that has long circulated through the surrounding neighborhood like an uninvited constant. EsSalud, Peru's social security health system, responded not with a single remedy but with layers of protection: fumigation, bed netting, natural repellents, and a call to the community to remove the standing water where mosquitoes are born. The episode speaks to a truth older than any pandemic — that illness rarely arrives alone, and that the places built to heal the sick can themselves become contested ground.
- COVID-19 patients at a Chiclayo hospital were found to have contracted dengue simultaneously, raising the alarming possibility that the facility itself had become a site of secondary infection.
- Authorities could not determine whether co-infections originated inside the hospital or in the surrounding endemic neighborhood, leaving a critical question unanswered as summer — dengue's peak season — approached.
- EsSalud deployed overlapping defenses: intensified fumigation, mosquito nets on every patient bed, daily natural repellents for patients and staff, and coordinated larval surveillance with regional health authorities.
- Hospital officials appealed urgently to the public to eliminate standing water and clear debris, warning that without community action, the health system's internal efforts would not be enough to hold the line.
- The strain on Lambayeque's health system deepened — patients already fighting for their lives against COVID-19 now faced the compounded risk of a second potentially fatal disease within the walls meant to protect them.
In mid-January 2021, health officials at Hospital Almanzor Aguinaga Asenjo in Chiclayo made a troubling discovery: patients hospitalized with COVID-19 had also contracted dengue. The hospital sits in Campodónico, a neighborhood long classified as endemic for dengue, and that geography immediately complicated the picture — no one could say with certainty whether the infections had occurred inside the facility or in the community beyond its walls.
EsSalud's response was layered by design. Fumigation operations were intensified to target the mosquito vector, bed nets were distributed to all hospitalized patients, and medical staff began applying natural repellents daily to both patients and healthcare workers. The hospital had already begun distributing nets the previous year as a precaution, but the co-infections gave the effort new urgency. Larval and adult mosquito surveillance was also coordinated with regional health authorities to monitor the threat continuously.
Gustavo Ganoza Tresierra, who managed the Lambayeque health network, made a direct appeal to the public: eliminate standing water, clear rooftop debris, and maintain clean water storage. Summer was arriving — the season when dengue transmission typically surges — and officials understood that no amount of hospital-level intervention could fully compensate for unchecked breeding sites in the surrounding community.
The situation exposed a deeper fragility. A health system already stretched by the pandemic now faced patients carrying two viruses at once, and a hospital meant to offer refuge had become a place where a second illness could find its way in. The discovery in Chiclayo was less an anomaly than a reflection of what it means to fight a modern epidemic inside an endemic zone.
In mid-January 2021, Peru's social security system discovered that patients hospitalized with COVID-19 at Hospital Almanzor Aguinaga Asenjo in Chiclayo had also contracted dengue. The discovery prompted an immediate escalation of disease control measures across the facility, as the health system struggled under the weight of two simultaneous epidemics.
The hospital sits in Campodónico, a neighborhood classified as endemic for dengue transmission. This geography created immediate uncertainty: officials could not determine whether the co-infected patients had picked up the virus inside the hospital walls or in the surrounding community. Cristian Díaz Vélez, head of the Epidemiological Intelligence Office for EsSalud Lambayeque, acknowledged the ambiguity. The region's status as a dengue hotspot meant the virus circulated constantly in the air and water around the facility.
EsSalud's response centered on three overlapping strategies. The health system intensified fumigation operations to target the mosquito vector, deployed mosquito netting on patient beds as a physical barrier, and worked with the regional health authority to conduct regular surveillance for mosquito larvae and adult insects. Gustavo Ganoza Tresierra, who managed the Lambayeque health network, explained that the hospital had already begun distributing bed nets to all hospitalized patients the previous year, regardless of whether they showed dengue symptoms. The goal was straightforward: prevent healthy patients from becoming infected while already fighting COVID-19.
Beyond fumigation and netting, the hospital's medical staff had developed natural repellents applied directly to patients and healthcare workers each day. This layered approach reflected the reality that a single intervention would not suffice. The facility was trying to create multiple obstacles between the mosquito and its human hosts.
Ganoza Tresierra also appealed directly to the public. He urged residents to eliminate standing water in containers, clear debris from roofs and yards, and maintain clean water storage—the basic practices that interrupt the mosquito's breeding cycle. Summer was arriving in the region, the season when dengue transmission typically accelerated. Without community participation in source reduction, even the hospital's intensive efforts would face limits.
The situation illustrated a deeper vulnerability in Lambayeque's health system. Already strained by the COVID-19 pandemic, the system now confronted patients carrying both viruses simultaneously. A person hospitalized with severe COVID-19 faced not only the original infection but the risk of acquiring a second, potentially fatal disease while in the facility meant to save their life. The discovery at Almanzor Aguinaga Asenjo was not an isolated incident but a symptom of the region's exposure to dengue and the difficulty of maintaining infection control in an endemic zone during a pandemic.
Citas Notables
It is not yet possible to determine whether hospitalized patients contracted the virus inside or outside the hospital, given that the neighborhood is considered an endemic dengue zone— Cristian Díaz Vélez, head of Epidemiological Intelligence Office, EsSalud Lambayeque
We have implemented mosquito nets on patient beds since last year to prevent infection, and specialists have developed natural repellents applied daily to patients and health workers— Gustavo Ganoza Tresierra, manager of Lambayeque health network
La Conversación del Hearth Otra perspectiva de la historia
Why does it matter that COVID patients caught dengue in a hospital? Aren't they already sick?
Because dengue can kill you, and it kills faster in people whose immune systems are already fighting COVID. You're asking a body to wage two wars at once. The hospital becomes a place where you go to recover and leave with something worse.
Could they have caught it outside the hospital instead?
That's the problem—nobody knows. The neighborhood is saturated with dengue. The mosquitoes don't respect hospital walls. That uncertainty is what forced them to act.
So they put up mosquito nets. Does that actually work?
It works if people use it correctly and if the nets stay intact. But it's a Band-Aid on a structural problem. You're trying to keep one mosquito out of a room when thousands are breeding in the neighborhood.
What about the fumigation?
It kills adult mosquitoes temporarily. But unless you eliminate the water where they breed—the buckets, the clogged gutters, the flower pots—the population bounces back within weeks. That's why they're asking residents to clean up their own yards.
Will people do that?
Some will. Many won't. It requires sustained effort and education. In a region already exhausted by pandemic lockdowns, asking people to maintain their yards is asking a lot. But it's the only way to actually reduce transmission.