In a recent study, University of Freiburg researchers coated Colombian water tanks for about $2 a year. Weeks later, dengue cases fell, showing one application could provide long-term protection against the tiger mosquito

Dengue mosquito control: A simple coating applied to household water containers was associated with a substantial reduction in dengue cases in Colombian neighbourhoods, according to researchers from the University of Freiburg.

The study, published in The Lancet Infectious Diseases on August 19, found that dengue cases fell 45% more in areas where water tanks received the coating than in comparable control areas.

The treatment cost around $2 per tank per year and was designed to target water containers where Aedes aegypti, the mosquito that spreads dengue, commonly breeds.


The coating remained effective for more than 12 months. The findings could also be relevant to Germany, where the closely related Asian tiger mosquito, Aedes albopictus, has become established in many regions.

A $2 treatment targets mosquito breeding sites

Researchers conducted the study in Cúcuta, Colombia, comparing 20 urban areas with around 1,600 to 2,000 households each.

One year after treatment, the areas with coated tanks recorded 337 dengue cases per 100,000 inhabitants, compared with 529 in the control areas.

The researchers also found a significant reduction in the proportion of homes containing mosquito larvae or pupae.

Previous safety studies showed that water from treated containers posed no health risk to humans.

How the coating works

The treatment is designed for water containers in and around homes. In Colombia, large washing tanks are among the most important breeding sites for Aedes aegypti.

It contains two active ingredients. One kills adult mosquitoes and inhibits egg-laying, while the other prevents larvae and pupae from developing.

Microcapsules slowly release the ingredients, allowing the coating to remain effective for more than 12 months.

Why targeting breeding sites matters

Dengue is a mosquito-borne viral infection that is increasing worldwide, with an estimated 100 million to 400 million people affected each year.

Most infections are mild, but severe cases can be fatal. The researchers say climate change, urbanisation and the spread of the tiger mosquito are also increasing the risk of local outbreaks in Europe.

By targeting places where mosquitoes breed, the coating offers another way to reduce the burden of dengue.

Could the approach be useful in Germany

The findings are also of interest to Germany because Aedes albopictus, the Asian tiger mosquito, uses water containers as breeding sites, including rain barrels in gardens and allotments.

Germany uses the biological agent Bti to control mosquito larvae in some water containers, but it must be reapplied every two weeks.

The researchers say a coating that remains effective for many months could reduce the burden on households and local authorities.

However, the Colombian results cannot be directly applied to Germany. The mosquito species, climate, container types and control programmes are different.

A do-it-yourself solution for Europe could be conceivable once the coating is approved.