Melanie Wiesner, Taye Tessema, Andreas Hoffmann, Pestemer Wilfried, Carmen Buettner, Inga Mewis, Christian Ulrichs:
Impact of the Pan-Tropical Weed Parthenium hysterophorus L. on Human Health in Ethiopia


1Humboldt-Universität zu Berlin, Institute for Horticultural Sciences, Urban Horticulture, Germany
2Plant Protection Research Center, Weed Science, Ethiopia
3Paul-Ehrlich-Institut, Federal Agency for Sera and Vaccines, Germany
4Humboldt Universität zu Berlin, Institute of Horticultural Science, Phytomedicine, Germany

Parthenium is an aggressive colonizer of wasteland, roadsides, railsides, watercourses, cultivated fields and overgrazed pastures. The impact on animal and human as well as the economic loss due to spreading of Parthenium in Ethiopia is severe.

Parthenium (Parthenium hysterophorus) is one of the worst weeds for agriculture, the environment and human health in Ethiopia. Parthenium is a genus in the family Asteraceae. It is native to Mexico and South America and has spread after its introduction prolifically in Ethiopia and its neighbour countries. Studies in other parts of the world have shown that Parthenium inhibits the growth and seed germination of other plants through allelopathy, and can also cause asthma and serious dermatitis in humans. Here most symptoms are contributed to the sesquiterpene lactone parthenin. However, detailed information on dose effects, the impact of other secondary plant compounds on human health, and the economic impact in Ethiopia are still missing.

In interviews we asked a total of 64 farmers (19-44 years old) in different infested territories in Ethiopia about their health problems when handling Parthenium. The following symptoms could be associated towards Parthenium: general illness (80%, tired, flappy), allergic reactions (90%, hay fever), asthmatic problems (62%, contraction of breath muscles, coughing fit), irritations of skin and pustules on hand balls (30%), stretching and cracking of skin (21%), stomach pains (22%, caused by the inhalation of pollen). The irritations of skin continue for one to two weeks. Apart from farmer interviews we have started to identify major secondary plant components in Parthenium at different developmental stages. For some of the identified substances we have looked in mouse experiments into the allergic potential. The statistical evaluation of the results is still ongoing.

Keywords: Ethiopia, human health, parthenin, Parthenium hysterophorus


Contact Address: Christian Ulrichs, Humboldt-Universität zu Berlin, Institute for Horticultural Sciences, Urban HorticultureLentzeallee 55, 14129 Berlin, Germany, e-mail:
Andreas Deininger, November 2007