In the northern city of Kano, the capital of one of 17 states where the haemorrhagic virus has been recorded, there have been "unprecedented" purchases of the pest control product.
The head of the city's chemicals traders, Shehu Idris Bichi, said sales have have increased four-fold since the outbreak was first announced earlier this month.
"Traders are doing brisk business because people are making unprecedented purchases of the product to rid their homes of rats that cause the disease," he told AFP.
"I used to get between five and 10 clients a day but now I get at least 30 customers... People you don't expect because of their social status," he said.
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"Lassa doesn't discriminate between the rich and the poor".
Vendors using megaphones and hawking their wares on carts have become commonplace.
"I was making up to 500 naira (USD 2.5, 2.3 euros) a day but now I make between 2,000 naira and 4,000 naira every day," said one, Awwalu Aminu, 40, in Kano.
Outbreaks are not uncommon and the US Centers for Disease Control and Prevention estimates there are between 100,000 to 300,000 infections in west Africa every year, with about 5,000 deaths.
In 2012, there were 1,723 cases and 112 deaths in Nigeria. Last year, 12 people died out of 375 infected, according to the Nigerian Centre for Disease Control.
The virus is spread through contact with food or household items contaminated with rats' urine or faeces.
But while the government maintains it has the spread of Lassa under control, specialists have voiced concern about under-reporting and Nigeria's capacity to deal with the outbreak.