Google goog has donated $1 million to the United Nations Children’s Emergency Fund (UNICEF) and some of its engineers are working with the agency to map the Zika virus outbreak.

The Zika virus, primarily transmitted by a type of mosquito, is already believed to have caused almost 5,000 cases of microcephaly in Brazil and has spread to other countries in Latin America. Microcephaly is a disorder that causes babies to be born with abnormally small heads, leaving them facing potential developmental problems and physical disabilities.

The World Health Organization declared the outbreak a public health emergency last month. However, as Google said in a blog post on Thursday, it’s difficult to map because most people with the virus don’t show any symptoms.

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Google said some of its engineers have volunteered to work with UNICEF on analysing data, to help try figure out where it’s going to spread next.

The firm said:

A volunteer team of Google engineers, designers, and data scientists is helping UNICEF build a platform to process data from different sources (i.e., weather and travel patterns) in order to visualize potential outbreaks. Ultimately, the goal of this open source platform is to identify the risk of Zika transmission for different regions and help UNICEF, governments and NGO’s decide how and where to focus their time and resources. This set of tools is being prototyped for the Zika response, but will also be applicable to future emergencies.

As for the $1 million grant, that’s intended to help UNICEF reach the public, develop vaccines and reduce mosquito populations. Google will also match employee donations with the goal of giving an extra $500,000 to UNICEF and the Pan American Health Organization.

Here’s a map showing the increased interest in the Zika virus Google has seen through its search requests.