Pie Müller

• PhD, Dipl Phil II
• Unit Head at Swiss Tropical and Public Health Institute

Mosquito-borne pathogens continue to cause tremendous suffering, morbidity and mortality. For many of these diseases, vector control remains the most effective approach. The development and deployment of effective and efficient mosquito control products and strategies require a profound understanding of mosquito behaviour. To study complex mosquito...

Background Sugar feeding is an essential aspect of mosquito biology that may be exploited for mosquito control by adding insecticides to sugar attractants, so-called ‘attractive targeted sugar baits’ (ATSBs). To optimize their effectiveness, ATSB products need to be maximally attractive at both short and long range and induce high levels of feeding...

Topical repellents provide protection against mosquito bites and their efficacy is often assessed using the arm-in-cage test. The arm-in-cage test estimates the repellent’s protection time by exposing a repellent-treated forearm to host-seeking mosquitoes inside a cage at regular intervals until the first confirmed mosquito bite. However, the test...

Malaria mosquitoes mate in swarms, but how these swarms are formed and maintained remains poorly understood. We characterized three-dimensional spatiotemporal flight kinematics of Anopheles coluzzii males swarming at sunset above a ground marker. The location, shape, and volume of swarms were highly stereotypic, consistent over the complete swarmin...

Background Indoor residual spraying (IRS) is one of the most effective malaria control tools. However, its application has become limited to specific contexts due to the increased costs of IRS products and implementation programmes. Selective spraying—selective spray targeted to particular areas/surfaces of dwellings—has been proposed to maintain t...

In addition to killing, mosquito nets treated with permethrin have been claimed to repel mosquitoes, reducing their success in passing through a holed net. We have tested this hypothesis by tracking mosquitoes in a modified World Health Organization tunnel test. In the original assay, mosquitoes are released at one end of the tunnel and have to pas...

Anopheles mosquitoes mate at sunset in aerial swarms. The development of mating-based methods for effective malaria vector control requires a good knowledge of the flight behaviour of Anopheles species in mating swarms. However, the process of how swarms are formed and maintained remains poorly understood. Here, we characterized the three-dimension...

Background Pyrethroid resistance in the key malaria vectors threatens the success of pyrethroid-treated nets. To overcome pyrethroid resistance, Interceptor® G2 (IG2), a ‘first-in-class’ dual insecticidal net that combines alpha-cypermethrin with chlorfenapyr, was developed. Chlorfenapyr is a pro-insecticide, requiring bio-activation by oxidative m...

In pursuing novel therapeutic solutions, drug discovery and development rely on efficiently utilising existing knowledge and resources. Repurposing know-how, a strategy that capitalises on previously acquired information and expertise, has emerged as a powerful approach to accelerate drug discovery and development processes, often at a fraction of...

Background Insecticide-based malaria vector control is increasingly undermined due to the development of insecticide resistance in mosquitoes. Insecticide resistance may partially be related to the use of pesticides in agriculture, while the level and mechanisms of resistance might differ between agricultural practices. The current study aimed to a...

Pyrethroid resistance in the key malaria vectors threatens the success of pyrethroid-treated nets. To overcome pyrethroid resistance, Interceptor® G2 (IG2), a ‘first-in-class’ dual insecticidal net that combines alpha-cypermethrin with chlorfenapyr was developed. Chlorfenapyr is a pro-insecticide, requiring bio-activation by oxidative metabolism wi...

Background Ivermectin (22,23-dihydroavermectin B1a: H2B1a) is an endectocide used to treat worm infections and ectoparasites including lice and scabies mites. Furthermore, survival of malaria transmitting Anopheles mosquitoes is strongly decreased after feeding on humans recently treated with ivermectin. Currently, mass drug administration of iverm...

In addition to killing, mosquito nets treated with permethrin have been claimed to repel mosquitoes, reducing their success in passing through a holed net. We have tested this hypothesis by tracking mosquitoes in a modified World Health Organization tunnel test. In the original assay, mosquitoes are released at one end of the tunnel and have to pas...

Background Insecticide-based malaria vector control is increasingly undermined due to the development of insecticide resistance in mosquitoes. Insecticide resistance may partially be related to the use of pesticides in agriculture, while the level and mechanisms of resistance might differ between agricultural practices. The current study aimed to a...

Durch die vermehrte Reisetätigkeit der letzten Jahrzehnte und den Import von Hunden aus dem Ausland könnten vermehrt Infektionskrankheiten in die Schweiz eingeführt werden. Eine davon ist die Dirofilariose verursacht durch Dirofilaria immitis oder D. repens. Eine Infektion mit D. repens, der Verursacherin der kaninen kutanen Dirofilariose, verläuft...

Background Knowing the species composition and insecticide resistance status of the target vector population is important to guide malaria vector control. The aim of this study was to characterize the malaria vector population in terms of species composition, insecticide susceptibility status and potential underlying resistance mechanisms in Ellibo...

Background Ivermectin (22,23-dihydroavermectin B1a: H2B1a) is an endectocide used to treat worm infections and ectoparasites including lice and scabies mites. Furthermore, survival of malaria transmitting Anopheles mosquitoes is strongly decreased after feeding on humans recently treated with ivermectin. Currently, mass drug administration of iverm...

Background The continued spread of insecticide resistance in mosquito vectors of malaria and arboviral diseases may lead to operational failure of insecticide-based interventions if resistance is not monitored and managed efficiently. This study aimed to develop and validate a new WHO glass bottle bioassay method as an alternative to the WHO standa...

Background: The continued spread of insecticide resistance in mosquito vectors of malaria and arboviral diseases may lead to operational failure of insecticide-based interventions if resistance is not monitored and managed efficiently. This study aimed to develop and validate a new WHO glass bottle bioassay method as an alternative to the WHO stand...

Background Colonization of large part of Europe by the Asian tiger mosquito Aedes albopictus is causing autochthonous transmission of chikungunya and dengue exotic arboviruses. While pyrethroids are recommended only to reduce/limit transmission, they are widely implemented to reduce biting nuisance and to control agricultural pests, increasing the...

Abstract Aedes albopictus originates from Southeast Asia and is considered one of the most invasive species globally. This mosquito is a nuisance and a disease vector of significant public health relevance. In Europe, Ae. albopictus is firmly established and widespread south of the Alps, a mountain range that forms a formidable biogeographic barrie...

Human and animal vector-borne diseases, particularly mosquito-borne diseases, are emerging or re-emerging worldwide. Six Aedes invasive mosquito (AIM) species were introduced to Europe since the 1970s: Aedes aegypti, Ae. albopictus, Ae. japonicus, Ae. koreicus, Ae. atropalpus and Ae. triseriatus. Here, we report the results of AIMSurv2020, the firs...

Background Prospective malaria public health interventions are initially tested for entomological impact using standardised experimental hut trials. In some cases, data are collated as aggregated counts of potential outcomes from mosquito feeding attempts given the presence of an insecticidal intervention. Comprehensive data i.e. full breakdowns of...

[This corrects the article DOI: 10.1371/journal.pntd.0006845.].

Insecticide resistance in Anopheles mosquitoes is seriously threatening the success of insecticide-based malaria vector control. Surveillance of insecticide resistance in mosquito populations and identifying the underlying mechanisms enables optimisation of vector control strategies. Here, we investigated the molecular mechanisms of insecticide res...

Fifth generation networks (5G) will be associated with a partial shift to higher carrier frequencies, including wavelengths comparable in size to insects. This may lead to higher absorption of radio frequency (RF) electromagnetic fields (EMF) by insects and could cause dielectric heating. The yellow fever mosquito (Aedes aegypti), a vector for dise...

Previous studies have indicated widespread insecticide resistance in malaria vector populations from Cameroon. However, the intensity of this resistance and underlying mechanisms are poorly known. Therefore, we conducted three cross-sectional resistance surveys between April 2018 and October 2019, using the revised World Health Organization protoco...

Background: Prospective malaria public health interventions are initially tested for entomological impact using standardised experimental hut trials. In some cases, data are collated as aggregated counts of potential outcomes from mosquito feeding attempts given the presence of an insecticidal intervention. Comprehensive data i.e. full breakdowns o...

Mosquitoes are vectors of major diseases such as dengue fever and malaria. Mass drug administration of endectocides to humans and livestock is a promising complementary approach to current insecticide-based vector control measures. The aim of this study was to establish an insect model for pharmacokinetic and drug-drug interaction studies to develo...

Over the past three decades, Europe has witnessed an increased spread of invasive aedine mosquito species, most notably Aedes albopictus, a key vector of chikungunya, dengue and Zika virus. While its distribution in southern Europe is well documented, its dispersal modes across the Alps remain poorly investigated, preventing a projection of future...

Background Aedes mosquito-borne arboviruses have (re-)emerged and caused considerable public health concerns in major sub-Saharan African cities subjected to rapid urbanisation. We assessed the effects of urbanisation on Aedes aegypti dynamics and biting pattern, and the risk of transmission of yellow fever (YF) and dengue (DEN) viruses along urban...

Les cassettes de forçage génétique ou guidage génétique (gene drives) sont des éléments génétiques d’organismes sexués qui modifient l’hérédité d’une caractéristique souhaitée. On peut s’en servir pour répandre un caractère pour modifier des individus ou bien pour réduire leur nombre dans des populations sauvages d’une espèce donnée. Comme ils se p...

Gene Drives sind genetische Elemente, welche die Vererbungsrate eines bestimmten Merkmals bei sich sexuell fortpflanzenden Organismen erhöhen. Sie können verwendet werden, um eine Eigenschaft in freilebenden Populationen zu verbreiten und diese dadurch zu verändern oder zu reduzieren. Da sich Gene Drives verbreiten, indem sie von einer Generation z...

Gene drives are genetic elements that skew the pattern of inheritance of a given characteristic in sexually reproducing organisms. They can be used to spread a characteristic that can alter or even reduce the numbers of individuals in wild populations of a certain species. As they spread by being inherited from one generation to the next, they coul...

People’s knowledge, attitudes, practices and beliefs (KAPB) pertaining to malaria are generally well described. However, little is known about population knowledge and awareness of insecticide resistance in malaria vectors. The aim of this study was to investigate KAPB related to insecticide resistance in malaria vectors due to the use of insectici...

Effective mosquito monitoring relies on the accurate identification and characterization of the target population. Since this process requires specialist knowledge and equipment that is not widely available, automated field-deployable systems are highly desirable. We present a centrifugal microfluidic cartridge, the VectorDisk, which integrates Taq...

Background: Understanding the dispersal dynamics of invasive mosquito species is fundamental to improve vector surveillance and to target control efforts. Aedes albopictus has been deemed a poor flyer as its range of active dispersal is generally assumed to be limited to a few hundred metres, while laboratory studies suggest this mosquito could ac...

The past 40 years have seen a dramatic emergence of epidemic arboviral diseases transmitted primarily by mosquitoes. The frequency and magnitude of the epidemics, especially those transmitted by urban Aedes species, have progressively increased over time, accelerating in the past 10 years. To reduce the burden and threat of vector-borne diseases, t...

Background: The threat of mosquito-borne diseases is increasing in continental Europe as demonstrated by several autochthonous chikungunya, dengue and West Nile virus outbreaks. In Switzerland, despite the presence of competent vectors, routine surveillance of arboviruses in mosquitoes is not being carried out, mainly due to the high costs associa...

Fungi produce various defense proteins against antagonists including ribotoxins. These toxins cleave a single phosphodiester bond within the universally conserved sarcin-ricin loop of ribosomes and inhibit protein biosynthesis. Here, we report on the structure and function of ageritin, a previously reported ribotoxin from the edible mushroom Agrocy...

Background Metabolic resistance of the major malaria vector Anopheles gambiae (s.l.) to insecticides is operationally significant, particularly in combination with target site resistance. However, detection of metabolic resistance is not trivial and relies on laborious bioassays, unspecific biochemical methods, or sophisticated and expensive molecu...

Background Diseases caused by Aedes-borne viruses, such as dengue, Zika, chikungunya, and yellow fever, are emerging and reemerging globally. The causes are multifactorial and include global trade, international travel, urbanisation, water storage practices, lack of resources for intervention, and an inadequate evidence base for the public health i...

Indoor residual spraying (IRS) is an important part of malaria control. There is a growing list of insecticide classes; pyrethroids remain the principal insecticide used in bednets but recently, novel non-pyrethroid IRS products, with contrasting impacts, have been introduced. There is an urgent need to better assess product efficacy to help decisi...

Global trade of plant products represents one of the major driving forces for the spread of invasive insect pests. This visualization illustrates the problem of unintended dispersal of economically harmful fruit fly pests using geospatial maps based on interception data from the Swiss import control process. Furthermore, it reports the development...

The whitefly Bemisia tabaci (Gennadius) is an invasive pest of considerable importance, affecting the production of vegetable and ornamental crops in many countries around the world. Severe yield losses are caused by direct feeding, and even more importantly, also by the transmission of more than 100 harmful plant pathogenic viruses. As for other i...

Bioassays and molecular diagnostics are routinely used for the monitoring of malaria vector populations to support insecticide resistance management (IRM), guiding operational decisions on which insecticides ought to be used for effective vector control. Previously developed TaqMan assays were optimised to distinguish the wild-type L1014 from the k...

Mosquitoes are important vectors of pathogens, and travellers to disease endemic countries are advised to avoid bites by applying topical repellents. Topical repellents are typically tested either in the arm-in-cage (AIC) test under laboratory conditions or in the field, but not often under both conditions. We, therefore, investigated how two topic...

Malaria control is dependent on the use of longlasting insecticidal nets (LLINs) containing pyrethroids. A new generation of LLINs containing both pyrethroids and the synergist piperonyl butoxide (PBO) has been developed in response to increasing pyrethroid resistance in African malaria vectors, but questions remain about the performance of these n...

Table S1. (Word document, 16.7 KB) Overview of types and positions of degeneracies used for LAMP primer design. Adenine (A), cytosine (C), guanine (G), thymine (T), M (A or C), R (A or G), W (A or T), Y (C or T).

Figure S1. (Word document, 23.9 KB) Pairwise genetic similarity matrices of insect specimens included in the on‐site evaluation with (A) the fruit fly assay, (B) the B. tabaci assay, (C) the T. palmi assay based on a part of the mitochondrial COI gene. Numbers represent percentage of bases which are identical. Fragment lengths: fruit fly assay, 386...

Table S2. (Word document, 12.3 KB) GenBank accession numbers of partial COI sequences from insect specimens analysed during the on‐site evaluation process.

Table S3. (Word document, 13.9 KB) Primer mismatch analyses of false‐negatively tested laboratory evaluation specimens. Adenine (A), cytosine (C), guanine (G), thymine (T), base pair (bp).

Metabolic resistance to pyrethroid insecticides is widespread in Anopheles mosquitoes and is a major threat to malaria control. DNA markers would aid predictive monitoring of resistance, but few mutations have been discovered outside of insecticide-targeted genes. Isofemale family pools from a wild Ugandan Anopheles gambiae population, from an area...

Monitoring malaria prevalence in humans, as well as vector populations, for the presence of Plasmodium, is an integral component of effective malaria control, and eventually, elimination. In the field of human diagnostics, a major challenge is the ability to define, precisely, the causative agent of fever, thereby differentiating among several cand...

Background: Rapid genetic on-site identification methods at points-of-entry, such as sea- and airports, have the potential to become important tools to prevent introduction and spread of economically harmful pest species that are unintentionally transported by the global trade of plant commodities. This paper reports the development and evaluation...

Background Identifying priority areas for vector control is of considerable public health relevance. Arthropod-borne viruses (arboviruses) spread by Aedes mosquitoes are (re)emerging in many parts of the tropics, partially explained by changes in agricultural land-use. We explored the effects of land-use changes on the abundance, distribution, and...

Aedes mosquito species occurrence among the microhabitats in different macrohabitats in southeastern Côte d’Ivoire surveyed from January to December 2014. Error bars represent the standard error (SE). NOM: naturally-occurring microhabitat, AOM: agriculturally-occurring microhabitat, MMM: man-made microhabitat. (TIF)

Outputs of data analysis comparing the mean numbers of Aedes eggs collected using metallic-ovitraps in polyculture with the other macrohabitats in oil palm-dominated landscapes in southeastern Côte d’Ivoire samples from January to December 2014. Results are the outputs of the generalized linear mixed model (GLMM) procedures. Results are considered...

Outputs of data analysis on positivity rates of Aedes collected as eggs using bamboo-ovitraps in oil palm-dominated landscapes in southeastern Côte d’Ivoire surveyed from January to December 2014. Results are the outputs of the generalized linear mixed model (GLMM) procedures. Results are considered significant for p-values <0.05. (DOCX)

Outputs of data analysis comparing the mean numbers of Aedes eggs using metallic-ovitraps in rainforest to the other macrohabitats in oil palm-dominated landscapes in southeastern Côte d’Ivoire sampled from January to December 2014. Results are the outputs of the generalized linear mixed model (GLMM) procedures. Result are considered significant fo...

Different macro- and microhabitat types sampled for Aedes mosquitoes in oil palm-dominated landscapes in southeastern Côte d’Ivoire. Potential habitats of Aedes mosquitoes are stratified into two habitat types: macrohabitats (A-D), and microhabitats (E-P). The habitat type often reflects the name of the habitats and the categories include habitats...

Standardized methods used for sampling different life stages of Aedes mosquitoes in the study area. A: Bamboo-ovitrap, B: Metallic-ovitrap, C: Larval survey, D: Human-baited double net trap. (TIF)

Monthly variations in Aedes mosquito species occurrence among the microhabitats in different macrohabitats in southeastern Côte d’Ivoire surveyed from January to December 2014. Error bars represent the standard error (SE). (TIF)

Outputs of data analysis on mean numbers of Aedes collected as eggs using bamboo-ovitraps in oil palm-dominated landscapes in southeastern Côte d’Ivoire surveyed from January to December 2014. Results are the outputs of the generalized linear mixed model (GLMM) procedures. Results are considered significant for p-values <0.05. (DOCX)

Outputs of data analysis on the mean numbers Aedes females’ host-seeking activities in oil palm-dominated landscapes in southeastern Côte d’Ivoire sampled from January to December 2014. Results are the outputs of the generalized linear mixed model (GLMM) procedures. Results are considered significant for p-values <0.05. (DOCX)

Relative proportions (%) of the different types of microhabitats among Aedes-positive microhabitats among the macrohabitats in southeastern Côte d’Ivoire surveyed from January to December 2014. Error bars represent the standard error (SE). NOM: naturally-occurring microhabitat, AOM: agriculturally-occurring microhabitat, MMM: man-made microhabitat....

Monthly variations in different types of microhabitats among Aedes-positive microhabitats among the macrohabitats in southeastern Côte d’Ivoire surveyed from January to December 2014. Error bars represent the standard error (SE). (TIF)

Synthesis of how land-use changes might affect the dynamics of Aedes mosquitoes in oil palm-dominated areas in southeastern Côte d’Ivoire. —: very low risk,—: low risk, +: high risk, ++: very high risk; %: percentage; SE: standard error of the mean. Host-seeking activity is expressed as the mean numbers of Aedes females collected per human-baited d...

Background Aedes aegypti and Ae. albopictus are two highly invasive mosquito species, both vectors of several viruses, including dengue, chikungunya and Zika. While Ae. aegypti is the primary vector in the tropics and sub-tropics, Ae. albopictus is increasingly under the public health watch as it has been implicated in arbovirus-transmission in mor...

Background Vector control is the only widely utilised method for primary prevention and control of dengue. The use of pyriproxyfen may be promising, and autodissemination approach may reach hard to reach breeding places. It offers a unique mode of action (juvenile hormone mimic) and as an additional tool for the management of insecticide resistance...

PRISMA checklist for “Community effectiveness of Pyriproxyfen as a Dengue Vector Control Method: A Systematic Review”. (TIF)

Background Failure in detecting naturally occurring breeding sites of Aedes mosquitoes can bias the conclusions drawn from field studies, and hence, negatively affect intervention outcomes. We characterized the habitats of immature Aedes mosquitoes and explored species dynamics along a rural-to-urban gradient in a West Africa setting where yellow f...

Range of Aedes mosquito breeding sites surveyed in rural, suburban, and urban areas in south-eastern Côte d’Ivoire from January 2013 to October 2014. The container type often reflects the name of the container and the categories include containers that provide comparable larval habitats as follows: A: rock hole, B: animal detritus, C: leaf, D: frui...