In French Guiana, a species of moth has residents fearful of going out at night and has also seen wartime-style curfews and blackouts put in place.
   
Nightly invasions of yellowtail moths that cause particularly nasty skin ailments are the culprits. 
   
It seems the female of the species releases thousands of microscopic hairs that cause terrible itching and severe urticarial and papulovesicular dermatitis. I've seen some photos of affected people and it looks extraordinarily unpleasant. 
   
Symptoms are worsened through the use of soap (an alkaline substance) but may be slightly alleviated with vinegar (acidic). According to this study, components of the hairs have a pH of 9 (alkaline), which may explain why soap promotes irritation.
   
The female moth's offending hairs do have an important function - to protect their eggs from predators. 
   
The moths breed in swamps of the Sinnamary region, but lights from local towns attract them in huge numbers during their reproductive season - another ill effect of light pollution. Like noise pollution, light pollution is a severely underrated environmental threat.
  
It must be hellish living under such conditions and one of the possible solutions being examined is spraying the nearby swamps during the moths' reproductive period. If this were to occur, it would be another example of us bringing a problem upon ourselves and then lashing out against nature in response.
  
I found it difficult to locate information on this particular species of moth (in English anyway); but as they are native to the area, they may play an important role in the local ecosystem and to take action that would effectively decimate the population may have some serious knock-on effects. Pesticides also have a very nasty habit of collateral damage - killing other non-target species of insects.
   
However, this is all very easy for me to say sitting here in a well-lit, moth-free room and not scratching myself like crazy - so for both the residents and the moths' sakes, here's hoping another more environmentally friendly solution can be found... very soon.