Spanish has two words for ‘malaria,’ one of them being malaria itself, which English shares. That noun originated in Italian, and if translated directly into Spanish it would have come out *malaire, which is to say ‘bad air.’ People once thought that “bad air” caused the disease.
The other Spanish word for ‘malaria’ is paludismo, which English once shared in the form paludism. This term was based on Latin palus, with stem palud-, which meant ‘marsh, swamp’ and is the source of the uncommon Spanish noun palude that means ‘lagoon, pond, pool.’ The connection, of course, is that malaria-spreading mosquitos thrive in places with still, fresh water. From the same Latin word, English (but apparently not Spanish) has paludal and the less common paludine and paludinous, all of which mean ‘having to do with a swamp or marsh.’ Similarly, something ‘growing or living in swamps or marshes’ is paludose. Spanish palúdico can mean ‘having to do with swamps or marshes’ as well as ‘suffering from malaria.’
© 2019 Steven Schwartzman