Common plant nectar could be used to help fight Leishmania infections

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, the researchers say.

Leishmania the parasites infect more than a million people a year, of whom more than 200,000 are infected with visceral leishmaniasis or kala-azar, the deadliest form of the disease, according to a study published in PLOS Neglected Tropical Diseases. It poses a greater health burden than any human parasite outside of malaria, according to the study.

The disease affects some of the world’s poorest people and is linked to issues such as malnutrition, poverty and weakened immunity, as well as environmental changes such as deforestation and urbanization, according to the report. ‘World Health Organization.

Leishmania the infection is spread by blood-sucking sandflies which also consume floral nectar, a complex of chemicals that arrest the growth of the parasite. “These same compounds could reduce infection in nectar-eating sandflies,” said Evan Palmer-Young, study author affiliated with the USDA-ARS Bee Research Laboratory, Beltsville, Maryland, USA.

The study showed that the concentrations of various phytochemicals (chemical compounds produced by plants) present in the nectar of the flowers were more than sufficient to prevent the growth of Leishmania.

If compounds in floral nectar are as effective against Leishmania pests in the natural environment as suggested by laboratory experiments, strategic cultivation of these plants could help reduce the burdens of Leishmania parasites in sandflies, the researchers said. “Such interventions could provide an environmentally friendly complement to existing means of disease control,” the study concludes.

“Unlike insecticide-based sandfly control methods, incorporating pest control nectar sources into landscapes and home environments could benefit public health without threatening beneficial insects,” Palmer-Young said. SciDev.Net. “These findings suggest an unexplored, landscape-based approach to reducing the transmission of a major neglected tropical disease globally.”

According to the researchers, flower nectar appears to be “a favorite food source” for sandflies. Additionally, nectar and pollen include several secondary metabolites which include flavonoids – a class of antimicrobial and antileishmanial compounds common to both nectar and pollen.

“This suggests that the consumption of nectars rich in secondary metabolites could attenuate the transmission of Leishmania by reducing the intensity of infection in vectors of nectar-feeding sandflies, indicating a new disease control strategy without drugs or insecticides” , say the researchers.

Visceral leishmaniasis can cause fever, enlarged liver and spleen, anemia, and weight loss. Other forms of the disease include cutaneous leishmaniasis – which causes ulcers and other skin lesions, often resulting in scarring and even disability – and mucocutaneous leishmaniasis, which damages the mucous membrane of the mouth, nose and throat.

Chiranjib Pal, a professor in the Department of Zoology, West Bengal State University, Barasat, India, said that while the authors suggested “a landscape ecology-based approach to reduce Leishmaniatransmission — this is an overall observation, not very precise”.

Researchers say the potential of nectar and pollen to limit Leishmania the epidemiology will depend on the contribution of nectar to sandfly diets and the extent to which success in laboratory tests is replicated in the intestines of infected flies.


Journal reference:

Palmer-Young, EC, et al. (2022) Can flower nectars reduce Leishmania transmission?. PLOS Neglected Tropical Diseases.

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