Insecticide susceptibility of <i>Phlebotomus argentipes</i> sandflies, vectors of visceral leishmaniasis in India

Dinesh, Diwakar Singh; Hassan, Faizan; Kumar, Vijay; Kesari, Shreekant; Topno, Roshan Kamal; Yadav, Rajpal

doi:10.1111/tmi.13576

“…One of the limitations of this study is that we had to implement the methodology and insecticide discriminating concentrations meant for testing the susceptibility of mosquitoes due to the absence of WHO standardized procedures and specific insecticide discriminating concentrations for testing the susceptibility of sand flies. Nonetheless, several authors have preceded us in the use of this adopted methodology to assess the susceptibility status of sand flies in the Indian subcontinent [10, 12, 30, 36]. A recent study in Sri Lanka has quantified far lower lethal concentrations of insecticides to kill 100% (LC 100 ) of P. argentipes as compared to discriminating concentrations used to monitor resistant status of mosquitoes [38].…”

Section: Discussionmentioning

confidence: 99%

Status of susceptibility of the visceral leishmaniasis vector,Phlebotomus argentipes(Diptera: Psychodidae: Phlebotominae), to insecticides used for vector control in Nepal

Roy

¹

,

Uranw

²

,

Cloots

³

et al. 2022

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BackgroundVisceral leishmaniasis (VL) is targeted for elimination as a public health problem in Nepal by 2023. For nearly three decades, the core vector control intervention in Nepal has been indoor residual spraying (IRS) with pyrethroids. Considering the long-term use of pyrethroids and possible development of resistance of the vector Phlebotomus argentipes sand flies, we monitored susceptibility status of their field populations to the insecticides of different classes, in villages with and without IRS activities in recent years.Methodology/Principal findingsSand flies were collected from villages with and without IRS in five VL endemic districts from August 2019 to November 2020. The WHO susceptibility test procedure was adopted using filter papers impregnated at the discriminating concentrations of insecticides of the following classes: pyrethroids (alpha-cypermethrin 0.05%, deltamethrin 0.05% and lambda-cyhalothrin 0.05%), carbamates (bendiocarb 0.1%) and organophosphates (malathion 5%). Pyrethroid resistance intensity bioassays with papers impregnated with 5× of the discriminating concentrations, piperonyl butoxide (PBO) synergist-pyrethroid bioassays and DDT cross resistance bioassays were also performed. In the IRS villages, the vector sand flies were resistant (mortality rate <90%) to alpha-cypermethrin and possibly resistant (mortality rate 90–97%) to deltamethrin and lambda-cyhalothrin, while susceptibility to these insecticides was variable in the non-IRS villages. The vector was fully susceptible to bendiocarb and malathion in all villages. A delayed knockdown time (KDT50) with pyrethroids was observed in all villages. The pyrethroid resistance intensity was low, and the susceptibility improved at 5× of the discriminating concentrations. Enhanced pyrethroid susceptibility after pre-exposure to PBO and the DDT-pyrethroid cross-resistance were evident.Conclusions/SignificanceOur investigation showed that P. argentipes sand flies have emerged with pyrethroid resistance, suggesting the need to switch to alternative classes of insecticides such as organophosphates for IRS. We strongly recommend for the regular and systematic monitoring of insecticide resistance in sand flies to optimize the efficiency of vector control interventions to sustain VL elimination efforts in Nepal.Author summaryVisceral leishmaniasis (VL), transmitted by P. argentipes sand flies, is endemic in South-East Asian countries such as Bangladesh, India and Nepal, and is on the verge of elimination as a public health problem in Nepal by 2023. As part of the WHO Global Vector Control Response, entomological surveillance including insecticide resistance monitoring is one of the four main pillars of this strategy. In the early 1990s, the historical use of DDT for sand fly vector control was replaced with deltamethrin or alpha-cypermethrin, which have now been in use for almost three decades in Nepal. Suspecting that this long-term use of pyrethroids might have selected resistance in sand fly populations which would jeopardize control efforts, we conducted the first comprehensive survey to generate contemporary evidence of insecticide resistance in Nepal. For this, we performed WHO susceptibility tests in five VL endemic districts and found strong evidence of pyrethroid resistance in vector populations from the areas receiving IRS. Resistance mechanisms involved would probably be kdr mutations and monooxygenase. This study also endorses regular insecticide resistance monitoring to inform evidence-based decisions on insecticide use for vector control and to maintain the effectiveness of vector control measures as a core intervention in the fight against VL.

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“…In a recent study in three states of India, P . argentipes populations showed full susceptibility to all insecticides except for DDT [ 36 ]. In Bangladesh, another VL endemic country neighboring to Nepal, the P .…”

Section: Discussionmentioning

confidence: 99%

“…Although P. argentipes populations were found susceptible to malathion in several locations within South-East Asia [30,31,34,35], resistant populations have also been detected [35]. In a recent study in three states of India, P. argentipes populations showed full susceptibility to all insecticides except for DDT [36]. In Bangladesh, another VL endemic country neighboring to Nepal, the P. argentipes populations have shown to be susceptible to insecticides in major classes used in IRS till date [12].…”

Section: Plos Neglected Tropical Diseasesmentioning

confidence: 99%

“…One of the limitations of this study is that we had to implement the methodology and insecticide discriminating concentrations meant for testing the susceptibility of mosquitoes due to the absence of WHO standardized procedures and specific insecticide discriminating concentrations for testing the susceptibility of sand flies. Nonetheless, several authors have preceded us in the use of this adopted methodology to assess the susceptibility status of sand flies in the Indian subcontinent [10,12,30,36]. A recent study in Sri Lanka has quantified far lower lethal concentrations of insecticides to kill 100% (LC 100 ) of P. argentipes as compared to discriminating concentrations used to monitor the resistant status of mosquitoes [38].…”

Section: Plos Neglected Tropical Diseasesmentioning

confidence: 99%

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Susceptibility status of the wild-caught Phlebotomus argentipes (Diptera: Psychodidae: Phlebotominae), the sand fly vector of visceral leishmaniasis, to different insecticides in Nepal

Roy

¹

,

Uranw

²

,

Cloots

³

et al. 2022

PLoS Negl Trop Dis

4

0

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Background Visceral leishmaniasis (VL) is targeted for elimination as a public health problem in Nepal by 2023. For nearly three decades, the core vector control intervention in Nepal has been indoor residual spraying (IRS) with pyrethroids. Considering the long-term use of pyrethroids and the possible development of resistance of the vector Phlebotomus argentipes sand flies, we monitored the susceptibility status of their field populations to the insecticides of different classes, in villages with and without IRS activities in recent years. Methodology/Principal findings Sand flies were collected from villages with and without IRS in five VL endemic districts from August 2019 to November 2020. The WHO susceptibility test procedure was adopted using filter papers impregnated at the discriminating concentrations of insecticides of the following classes: pyrethroids (alpha-cypermethrin 0.05%, deltamethrin 0.05%, and lambda-cyhalothrin 0.05%), carbamates (bendiocarb 0.1%) and organophosphates (malathion 5%). Pyrethroid resistance intensity bioassays with papers impregnated with 5× of the discriminating concentrations, piperonyl butoxide (PBO) synergist-pyrethroid bioassays, and DDT cross-resistance bioassays were also performed. In the IRS villages, the vector sand flies were resistant (mortality rate <90%) to alpha-cypermethrin and possibly resistant (mortality rate 90–97%) to deltamethrin and lambda-cyhalothrin, while susceptibility to these insecticides was variable in the non-IRS villages. The vector was fully susceptible to bendiocarb and malathion in all villages. A delayed knockdown time (KDT50) with pyrethroids was observed in all villages. The pyrethroid resistance intensity was low, and the susceptibility improved at 5× of the discriminating concentrations. Enhanced pyrethroid susceptibility after pre-exposure to PBO and the DDT-pyrethroid cross-resistance were evident. Conclusions/Significance Our investigation showed that P. argentipes sand flies have emerged with pyrethroid resistance, suggesting the need to switch to alternative classes of insecticides such as organophosphates for IRS. We strongly recommend the regular and systematic monitoring of insecticide resistance in sand flies to optimize the efficiency of vector control interventions to sustain VL elimination efforts in Nepal.

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“…Meanwhile, chemical management is still regarded as an e cient strategy for reducing sand y population density (11). In one side vector of human diseases (malaria and leishmaniasis) continues to be highly resistant to synthetic insecticides (12,13), such as Phlebotomus Argentipes to dichloro-diphenyltrichloroethane (DDT) (14) and P. papatasi to Pytethroid insecticide (15). In the other side, insecticides are having adverse effect on the human health and environment (16).…”

Section: Introductionmentioning

confidence: 99%

Repellent and insecticidal activities of vegetal material against sand fly populations (Diptera: Psychodidae): Systematic review and Metaanalysis.

AMANE¹,

Echchakery²,

Zuhair³

et al. 2022

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Leishmaniasis is a vector-borne disease that is widely distributed among humans and animals. Furthermore, it can be transmitted by a bite from an infected female phlebotomine sand fly (Diptera: Psychodidae). Chemical control strategies are still regarded as an efficient means of reducing vector-borne disease population density. However vector-borne diseases have become increasingly resistant to synthetic pesticides. Also, insecticides have a negative impact on human health and the ecosystem in general. As a result, ecologically acceptable alternative strategies are more important than ever for the management of disease-spreading vectors. Numerous databases were searched for information on the botanical effects on sand flies (PubMed, Scopus, Science Direct, Web of Science, CAIRN, and the Cochrane Library). Up until June 2021, 2676 papers were reviewed and analyzed in accordance with PRISMA. A total of 58 plants were investigated, with 303 experiments conducted to examine insecticidal activity and 115 others conducted to investigate the insect repellent properties of medicinal plants against 11 species of sand flies belonging to the genera Lutzomyia and Phlebotomus. The investigation of the influence of natural products on sand fly revealed a wide range of variability, with an I squared over than 80%. Briefly, plant insecticide efficacy was observed in Monticalia greenmaniana (Asteraceae) and Nicotiana tabacum (Solanaceae). However, Meliaceae, particularly neem oil, exhibited the most activity as a sand fly repellent. Concerning sand flies, Lutzomyia Migonis had the most sensitivity to natural insecticides, whereas Phlebotomus Argentipes, P. orientalis, and P. bergeroti were more susceptible to botanical repellents. It's also worth mentioning that while a sand fly is in its egg stage, it's more susceptible to the botanical insecticide than when it's an adult. The research using aerial plants were the most likely to result in mortality. Despite this, during repellency testing, leaves were the most effective. Even though several studies are being performed to assess the efficacy of botanical products against sand flies, few of these research investigations are being conducted in North Africa. As a result, research into the potential of local plants in North Africa to prevent leishmaniasis vectors is becoming important.

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Insecticide susceptibility of Phlebotomus argentipes sandflies, vectors of visceral leishmaniasis in India

Cited by 10 publications

References 17 publications

Status of susceptibility of the visceral leishmaniasis vector,Phlebotomus argentipes(Diptera: Psychodidae: Phlebotominae), to insecticides used for vector control in Nepal

Status of susceptibility of the visceral leishmaniasis vector,Phlebotomus argentipes(Diptera: Psychodidae: Phlebotominae), to insecticides used for vector control in Nepal

Susceptibility status of the wild-caught Phlebotomus argentipes (Diptera: Psychodidae: Phlebotominae), the sand fly vector of visceral leishmaniasis, to different insecticides in Nepal

Repellent and insecticidal activities of vegetal material against sand fly populations (Diptera: Psychodidae): Systematic review and Metaanalysis.

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