“High” cloud appears that sometimes darkens over our heads

(The press is discussing whether a new invasion of mosquitoes could lead to a recurrence of yellow fever.)
(Cloud of mosquitoes labeled “yellow fever,” “purple,” “green,” “blue,” “etc.”)
City of Rio: “Go away, long-legged bandits! Go away, damn vehicles of fevers of all colors! Go away!”
Dr. Seidl: “Don’t be so scared, madame! Here I am armed to the teeth against this horde of mosquitoes!”
Joe Public: “Hey, doc, the lady is right! You can have a lot of strength and a lot of goodwill, but… a swallow just doesn’t make summer! Against this cloud, which darkens the air and appears over our heads, I see only one remedy: the replacement of the strategic killer-mosquito brigade. Are there not so many others here? Because this is useful!…”
(O Malho, Rio de Janeiro, 1912)