[The use of the Knott technic in an endemic area of filariasis in Puerto Limon, Costa Rica].

One hundred and nineteen people living in the Roosevelt county of Puerto Limón were submitted to the Knott technique for diagnosing microfilaremia bancrofti. This was the first time the technique was applied in Costa Rica. A 17.6% positivity was obtained. Some considerations on filariasis spreading to other regions of the country with the possibility of outbreaks of tropical eosinophilia or filariasis without microfilaremia are made.