Loa-loa microfilaremia in the Nigerian population.

In about half of 1026 Nigerians infected with Loa loa, the microfilaria levels were low, less than 8% had more than 1000 microfilariae in 50 cumm blood. The length range of 445 microfilariae obtained from 39 infected people was 156.8 to 308.7 micron with a mean of 236.4 micron, or microgram; smaller than in the Kumba strain of Cameroon. The persistence of a rather high number of microfilariae in the peripheral blood of four patients till 22 hours was discussed in relation to the importance of Mansonia africana mosquitoes as a vector of Loa loa.