Dengue continues to represent a major public health challenge in the Region of the Americas. Although a reduction has been observed during the first months of 2026 compared to periods of higher incidence, the Pan American Health Organization continues to recommend strengthening epidemiological and entomological surveillance.
This situation shows that a temporary decrease in cases does not mean the risk has disappeared. The Aedes aegypti mosquito, the main transmitter of dengue, is closely adapted to urban environments and can find suitable breeding sites during much of the year.
For this reason, cities and environmental health companies need to evolve from campaigns concentrated in specific months towards continuous vector surveillance programmes. The objective is not to apply treatments constantly, but to maintain a stable capacity to detect activity, identify risks and act before an outbreak appears.
Dengue Remains an Urban Risk
Dengue is a viral disease transmitted mainly by mosquitoes of the species Aedes aegypti. In some areas, Aedes albopictus, also known as the tiger mosquito, may also be involved.
Unlike other vectors associated with large wetlands or natural areas, these mosquitoes have developed a strong ability to live close to people. They use small containers with water to reproduce and find food, shelter and favourable temperatures in cities.
Virus circulation can change rapidly due to factors such as population mobility, climate conditions, urban density and the presence of different serotypes.
This means that municipalities should not wait for case notifications to increase before taking action. Prevention must begin earlier, through constant knowledge of the vector’s distribution and the conditions that favour its reproduction.
Why Cities Favour the Presence of Aedes aegypti
Urban breeding sites are not always large accumulations of water. In many cases, they are found in everyday elements such as plant pots, buckets, gutters, water tanks, tyres, drains, abandoned containers or construction areas.
A small amount of water can be enough to complete the mosquito’s reproductive cycle. This means that breeding sites are highly dispersed and cannot be controlled only through one-off treatments.
There can also be significant differences within the same city. Some neighbourhoods present a higher risk due to population density, water storage, sanitation conditions, building types or the presence of vacant lots and public spaces with insufficient maintenance.
For this reason, applying the same campaign across an entire municipality may be inefficient. Surveillance should help identify where the risk is truly concentrated and which areas require priority attention.
The Limitations of Seasonal Campaigns
Many mosquito control strategies are still concentrated during periods of higher temperature or rainfall. This planning makes sense from a biological perspective, but it can be insufficient when surveillance disappears during the rest of the year.
If inspections begin only when increased activity has already been detected, the mosquito population may already be established and teams are forced to work reactively.
In addition, the lack of continuous information makes it difficult to answer important questions:
- Which breeding sites appear repeatedly?
- In which neighbourhoods does activity begin earlier?
- Which interventions have worked?
- Where are alerts repeated?
- Which facilities require closer monitoring?
Year-round surveillance does not mean applying biocides permanently. It means maintaining a basic structure of observation, inspection and recording that can be intensified when indicators show an increase in risk.
How Continuous Vector Surveillance Works
An effective programme must combine different types of information and adapt actions to the situation of each area.
Inspection of Critical Points
Inspections should focus especially on places at risk of water accumulation, such as sanitation networks, parks, cemeteries, schools, markets, vacant lots, construction sites, healthcare centres and public buildings.
Each inspection must be recorded so that results can be compared and changes detected over time.
Monitoring with Ovitraps
Ovitraps help identify reproductive activity and analyse trends. Their usefulness increases when they are kept in stable locations and their results are related to environmental conditions and the interventions carried out.
Risk Mapping
The geolocation of breeding sites, captures, alerts and treatments makes it possible to identify patterns that would be difficult to observe in isolated reports.
Risk maps help prioritise resources and make it easier to check whether activity decreases after an intervention.
Elimination of Breeding Sites
Reducing breeding sites remains one of the most important measures. Emptying containers, closing water tanks, improving drainage and correcting structural deficiencies can be more effective in the long term than repeatedly treating adult mosquitoes.
Evaluation of Results
The programme must verify what happens after each action. Simply recording that a visit was carried out does not make it possible to know whether the breeding site was eliminated, whether it reappeared or whether the protocol needs to be modified.
The Role of Environmental Health Companies
Specialised companies can become a strategic support for municipalities, communities and organisations with facilities distributed across different urban areas.
Their role should not be limited to acting when an infestation appears. They can also participate in:
- Preventive inspections.
- Installation and review of monitoring devices.
- Identification of breeding sites and risk factors.
- Creation of activity maps.
- Application of corrective measures.
- Evaluation of results.
- Preparation of reports for customers and authorities.
To carry out this work, it is essential to use standardised procedures. All technicians must record information according to the same criteria: location, type of point, activity detected, conditions found, measures applied and recommendations.
When these data are complete and comparable, the company stops offering only a reactive service and starts providing knowledge about the real evolution of risk.
It is also necessary to establish different levels of response. An isolated detection does not necessarily require the same intervention as high activity near a school, hospital or densely populated area.
Surveillance makes it possible to adjust the effort and apply treatments only when they are justified by the information available.
Digitalisation and Data Management
Continuous surveillance programmes can generate a large volume of records. If the information is spread across paper documents, spreadsheets, photographs and emails, it becomes difficult to transform it into useful decisions.
Digitalisation makes it possible to centralise:
- Control points.
- Inspections and reviews.
- Geolocated alerts.
- Photographs and evidence.
- Treatments applied.
- Products used
- Activity history.
- Heat maps.
- Technical reports.
- Results from connected devices.
Specialised platforms such as iGEO ERP Cloud Platform make it possible to connect the information collected by technicians with service planning, facility plans, alerts, documentation and subsequent analysis. They also facilitate the integration of IoT devices and access to real-time information.
The value of these tools does not simply lie in storing more information. Their usefulness appears when they make it possible to detect recurring breeding sites, compare areas, evaluate the effectiveness of interventions and anticipate operational needs.
However, technology must be supported by high-quality data. An incorrect location, an incomplete inspection or different criteria between technicians can affect the analysis. Training, standardisation and information review remain essential elements.
Conclusion: Always Monitor to Intervene Better
The evolution of dengue in the Americas confirms that the risk may temporarily decrease without disappearing. Cities continue to offer favourable conditions for mosquito reproduction, and the situation can change quickly.
In this scenario, campaigns limited to the months of highest activity are becoming increasingly insufficient. Vector surveillance must become a stable process, even if its intensity is adapted to each season and each area.
This approach makes it possible to:
- Detect vector activity earlier.
- Identify recurring breeding sites.
- Prioritise higher-risk neighbourhoods and facilities.
- Plan resources more effectively.
- Reduce unnecessary interventions.
- Evaluate the effectiveness of actions.
- Maintain complete traceability.
- Improve coordination between companies, authorities and citizens.
Prevention does not begin when the first cases appear. It begins during periods of lower activity, when there is room to inspect, correct deficiencies and prepare a proportionate response.
Working throughout the year does not mean treating more. It means monitoring better in order to intervene only where, when and how it is necessary.
