According to researchers, the nectar of common plants such as sunflower contains bioactive agents that can inhibit the growth of Leishmania and could be used to help fight the life-threatening disease caused by the parasite.
Leishmania parasites infect more than a million people a year, more than 200,000 of whom are infected with visceral leishmaniasis or kala-azar, the deadliest form of the disease, according to a study published in PLOS Neglected Tropical Diseases . This is a greater health burden than any human parasite in addition to malaria, the study says.
The disease affects some of the world’s poorest people and is linked to problems such as malnutrition, poverty and weakened immunity, as well as environmental changes such as deforestation and urbanization, according to the World Health Organization.
Leishmania infection is transmitted by blood flies that feed on blood and also consume floral nectar, a complex of chemicals that stop the growth of the parasite. “These same compounds could reduce infection in nectar-consuming sand flies,” said Evan Palmer-Young, author of the study affiliated with the USDA-ARS Bee Research Laboratory in Beltsville, Maryland, USA.
The study showed that the concentrations of various phytochemicals (chemical compounds produced by plants) present in the nectar of flowers were more than enough to prevent the growth of Leishmania.
If floral nectar compounds are as effective against Leishmania parasites in the wild as laboratory experiments suggest, strategic cultivation of these plants could help reduce Leishmania parasite loads in sand flies. say the researchers. “These interventions could provide an environmentally friendly complement to existing means of disease control,” the study concluded.
“In contrast to sandfly-based insecticide-based methods, the incorporation of antiparasitic nectar sources into landscapes and domestic environments could benefit public health without threatening beneficial insects,” Palmer-Young told SciDev. Net. “These findings suggest an unexplored, landscape-based approach to reducing the transmission of a major neglected tropical disease worldwide.”
According to researchers, flower nectar appears to be “a favorite food source” for sand mosquitoes. In addition, nectar and pollen include several secondary metabolites that include flavonoids, a class of antimicrobial and antileishmanial compounds common to both nectar and pollen.
“This suggests that the consumption of metabolite-rich secondary nectars could mitigate the transmission of Leishmania by reducing the intensity of infection in nectar-fed sand fly vectors, pointing to a new strategy for drug-free disease control and insecticides, “say the researchers.
Visceral leishmaniasis can cause fever, increased liver and spleen, anemia, and weight loss. Other forms of the disease include cutaneous leishmaniasis – which causes ulcers and other skin lesions, which often cause scarring and even disability – and mucocutaneous leishmaniasis, which damages the mucous membrane of the mouth, nose and throat.
Chiranjib Pal, a professor in the zoology department at West Bengal State University in Barasat, India, said that while the authors have suggested “a landscape-based approach to reducing Leishmania transmission, this is a general observation, not a very specific one. ” .
Researchers say the potential for nectar and pollen to limit the epidemiology of Leishmania will depend on the contribution of nectar to sand fly diets and the extent to which the success of laboratory tests reproduces in the bowels of infected flies.
Source:
Magazine reference:
Palmer-Young, EC, et al. (2022) Can floral nectars reduce Leishmania transmission ?. PLOS Neglected Tropical Diseases. doi.org/10.1371/journal.pntd.0010373.