A Liberian Journey

Creator

Richard Pearson Strong

Date

9/21/26

Coverage

Gbanga, Hinterland, Liberia

Transcription

Tuesday, September 21st.

Yesterday I went to look for a breeding place of Simulium damnosum. I think I have spoken before of this black fly. It has recently been claimed that it is the intermediate host of Onchocerca volvulus, (which infects man and which is so common along this part of the West Coast). I have been trying to get Bequaert to collect this fly for the last week but he has been very busy in helping Linder with the botanical work, which is also important. After a search of an hour and a half I found a place along the river with swift running water among rocks. This morning I took Bequaert and two natives and went to this place. We first had the natives stand in the water and lift up the stones to be examined. We soon found the little tunnels of earth the larvae make along the under surface of the rocks beneath the water and with our hand lenses could see the larvae moving up and down in these tunnels. We also found a number of the larvae on the leaves of branches which reached into the water. Bequaert also found two pupae on a rock. We then sat down to catch the full grown flies, which we felt would probably soon come, as we had found their breeding place. Soon they began to come. We exposed our arms to attract them, but they seemed to prefer the black legs of the natives, from whom we caught quite a number in our test tubes, while they were biting. A number were also collected from my leather leggings, which are dark brown. They bite particularly around the legs. Finally we caught 21 flies, all alive, and brought them back for dissection and study. While we were dissecting these I noticed one biting the arm of Bequaert in the laboratory. This one was also caught, dissected and examined. In its stomach and thoracic muscles there were eight filariae, all actively motile. I made a permanent specimen of it. The other twenty-one flies were all dissected and examined but nothing was found in them.

If we had not caught this one fly in the laboratory and examined it, all our work with these flies today would have been negative. One must make use of every opportunity in order to occasionally be successful. Chances are rare in scientific work as a rule. We shall of course examine some of these flies from about the town. I have thought that the flies about here would be infected, and although they occasionally bite us while at work they have not yet been common and it has been hard to get specimens of them.

They will probably be more numerous in the drier season. These are a larger and different species from those that were so annoying on the Amazon and their bite is not so irritating. I have two bites on my arm, which I can see as I write, merely bright red purpurine spots about 2 mm. in diameter. Today’s observations are of considerable importance.

Type

Diary

Citation