The Invasive American Weed Parthenium hysterophorus Can Negatively Impact Malaria Control in Africa

Abstract

The direct negative effects of invasive plant species on agriculture and biodiversity are well known, but their indirect effects on human health, and particularly their interactions with disease-transmitting vectors, remains poorly explored. This study sought to investigate the impact of the invasive Neotropical weed Parthenium hysterophorus and its toxins on the survival and energy reserves of the malaria vector Anopheles gambiae. In this study, we compared the fitness of An. gambiae fed on three differentially attractive mosquito host plants and their major toxins; the highly aggressive invasive Neotropical weed Parthenium hysterophorus (Asteraceae) in East Africa and two other adapted weeds, Ricinus communis (Euphorbiaceae) and Bidens pilosa (Asteraceae). Our results showed that female An. gambiae fitness varied with host plants as females survived better and accumulated substantial energy reserves when fed on P. hysterophorus and R. communis compared to B. pilosa. Females tolerated parthenin and 1-phenylhepta-1, 3, 5-triyne, the toxins produced by P. hysterophorus and B. pilosa, respectively, but not ricinine produced by R. communis. Given that invasive plants like P. hysterophorus can suppress or even replace less competitive species that might be less suitable host-plants for arthropod disease vectors, the spread of invasive plants could lead to higher disease transmission. Parthenium hysterophorus represents a possible indirect effect of invasive plants on human health, which underpins the need to include an additional health dimension in risk-analysis modelling for invasive plants.

Alteration of plant species assemblages can decrease the transmission potential of malaria mosquitoes

“…For instance, the status of P. hysterophorus as a poor provider of sugar—it appears that although the flowers do yield nectar, they do so only in very small quantities that are rapidly digested—conflicts with the results of Nyasembe et al. (). One possible explanation for this discrepancy is that a more nectariferous biotype exists in upland Kenya, near Nairobi; ours was from Mbita Point (Lake Victoria region), the source of our mosquito strain, where malaria is endemic.…”

“…This plant has been described as being sugar‐poor yet attractive to A. gambiae , females of which readily settle on it (Manda, Gouagna, Nyandat, et al., ), but it sustains life only for short periods (Manda, Gouagna, Foster, et al., ; Nikbakhtzadeh et al., ; Stone et al., ). Other accounts suggest that P. hysterophorus is an important sugar source for A. gambiae , lengthening its longevity and thus its vectorial capacity, and thereby promoting malaria prevalence (Nyasembe et al., ). Here, we test whether this discrepancy may be due to its flowering status.…”

The Nonartemisinin Sesquiterpene Lactones Parthenin and Parthenolide Block Plasmodium falciparum Sexual Stage Transmission

“…Parthenin was isolated from whole plant tissue using methanol extraction and purified by high performance liquid chromatography (HPLC) (41). The extract was dissolved into acetone and then diluted 1:10 into water to give a stock solution of 5 mg/ml.…”

Parthenium Hysterophorus. L. (Asteraceae) : A Boon or Curse? (A Review)

“…One report shows that the toxic impact present on P. hysterophorus positively impact on the survival & energy reserves of malaria vector Anopheles gambiae. Females Anopheles gambiae survived better & accumulated energy reserves when fed on P. hysterophorus 41 .…”