Mosquitoes are responsible for transmitting a significant number of infections around the globe. Vaccines or chemoprophylaxis can protect against very few of theses diseases, and current outbreaks of Zika and chikungunya viruses are causing significant concern. This article looks at four of the most significant infections that travellers from the UK should be advised about before travel. It describes sources of infection, symptoms and preventive measures, and emphasises the need for practice nurses to be alert to ecent international travel when assessing patients who subsequently become unwell.