Onchocerca parasites can not be transferred to any small laboratory animal and the cycle of development can not be kept in-vitro. This is why it is so important to have a constant source of fresh materials from a natural host. Every morning at 6 hrs, we go to the nearby slaughterhouse and collect pieces of the skin of the cow-udder, where most of the nodules of Onchocerca ochengi are located. Every nodule contains one male and one female adult worm, on an average. Per square millimeter of skin, up to some 50 microfilariae can be collected by a simple Baerman technique.
collection of O. ochengi microfilariae from the skin of cattle
The adult worms are isolated from the nodules by digestion with the enzyme collagenase at 35 ° for one day. The worms, that still live then, are kept in-vitro to harvest Excretory-Sectretory Products (ESPs).
MVI_0036 => click to see moving adult Onchocerca ochengi worm
In 2009 the in-vitro laboratory was set up, with two rooms, one with a sterile hood and 36 °C incubator for the collagenase-digestion of the nodules and another room for the in-vitro culture in a CO2-incubator.