Invasive species have been on the rise around the world over the last decade, and so has the amount of money lost to them. In addition to the ecological problems they cause in the ecosystem, invasive species can lead to economic losses in agriculture, tourism and public health as managers have to deal with the damage they cause. Researchers recently looked at biological invasions around the world and estimated that invasive species have cost humans at least $1.288 trillion from 1970 to 2017. In 2017 alone, the money spent on invasives reached $162.7 billion. That was 20 times the budget of the World Health Organization and the United Nations Secretariat that year. Mosquitos were the most damaging, followed by rats and cats. Researchers say more money is needed to prevent, monitor and combat the spread of these species.