Evaluation of the presence of Onchocerca volvulus infection in Black fly vectors in the Tunduru focus of Tanzania

Onchocerciasis can be prevented by treating communities at risk every year with a dose of ivermectin.  Evidence suggests that instead of just preventing blindness and skin diseases associated with Onchocerciasis, ivermectin can be used to eliminate the parasite permanently from the community.  The World Health Organization (WHO) guidelines for the elimination of Onchocerciasis require the evaluation of infection in black flies using human landing collections.  In order to calculate the annual transmission potential, which is an estimate of the number of infected flies an individual is bitten by, one needs to know daily biting rate over the transmission season in addition to the number of infected flies.  We are planning to implement a human landing collection in Tunduru focus that had more than a decade of mass drug administration (MDA) with ivermectin and data in humans suggest that transmission may have stopped.  Villagers will be hired to collect wild adult black fly after providing voluntary written consent. Flies will be collected at six chosen catching points as per WHO/OCP standard method of fly catching during dry season of year when biting rates is high. 
Collected adult Simulium damnosm complex will be preserved in pools of 100 flies in 1.5ml tubes. Both pools of heads and bodies of flies will be analyzed by PCR (pool screening test) O-150 for detection of infection of Onchocerca volvulus as alternative method to measure the annual transmission potential. A demonstration of ATP between 2 and 18 is considered non-sustainable and thus evidence of the interruption of transmission and otherwise. The entomological data will allow us to better interpret the results once analysis of humans samples so as to recommend the best approach to either stop MDA with ivermectin or continue treating affected communities.