A5005581878- Malaria Research and Control
- Mosquito-borne diseases and control
- Insect Pest Control Strategies
- Insect Resistance and Genetics
- Insect symbiosis and bacterial influences
- Parasites and Host Interactions
- Viral Infections and Vectors
- Entomopathogenic Microorganisms in Pest Control
- Environmental Toxicology and Ecotoxicology
- Insect Utilization and Effects
- Invertebrate Immune Response Mechanisms
- Viral Infections and Outbreaks Research
- Herpesvirus Infections and Treatments
- Physiological and biochemical adaptations
- Piperaceae Chemical and Biological Studies
- Parallel Computing and Optimization Techniques
- Rabies epidemiology and control
- Neurobiology and Insect Physiology Research
- Insect and Pesticide Research
- Computational Drug Discovery Methods
- Epigenetics and DNA Methylation
- Entomological Studies and Ecology
- Parasite Biology and Host Interactions
- Cancer-related gene regulation
- Vector-Borne Animal Diseases
University of the Witwatersrand
2015-2024
National Health Laboratory Service
2011-2023
National Institute for Communicable Diseases
2014-2023
Institut de Recherche en Sciences de la Santé
2022
University of Pretoria
2021
Copperbelt University
2021
Leiden University
2021
University of Warwick
2021
Brooke
2021
Universidade Nova de Lisboa
2021
Summary Northern Kwazulu/Natal (KZN) Province of South Africa borders on southern Mozambique, between Swaziland and the Indian Ocean. To control malaria vectors in KZN, houses were sprayed annually with residual DDT 2 g/m until 1996 when treatment changed to deltamethrin 20–25 mg/m . At Ndumu (27°02′ S, 32°19′ E) recorded incidence increased more than six‐fold 1995 1999. Entomological surveys during late 1999 found mosquitoes Anopheles funestus group (Diptera: Culicidae) resting some sectors...
Malaria in South Africa is primarily transmitted by Anopheles funestus Giles. Resistance to pyrethroid insecticides An. northern Kwazulu/Natal, Africa, and neighbouring areas of southern Mozambique enabled populations this species increase their ranges into where pyrethroids were being exclusively used for malaria control. Pyrethroid resistance African conferred monooxygenase enzyme metabolism. However, selection mechanism likely have occurred conjunction with other factors that improve...
Anopheles funestus Giles has been implicated as a major malaria vector in sub-Saharan Africa where pyrethroid insecticides are widely used agriculture and public health. Samples of this species from northern Kwazulu/Natal South the Beluluane region southern Mozambique showed evidence resistance to insecticides. Insecticide exposure, synergist biochemical assays conducted on A. suggested that elevated levels mixed function oxidases were responsible for detoxification pyrethroids resistant...
Abstract. A laboratory colony of Anopheles funestus Giles (Diptera: Culicidae) was established in 2000 from material collected southern Mozambique where pyrethroid resistance had been demonstrated the wild population. subsample selected for using 0.1% lambda‐cyhalothrin. Bioassay susceptibility tests subsequent generations F 2 to 4 showed increased with each successive generation. Survival individual mosquitoes fed only on 10% sugar solution, age up days, but by day 10 decreased...
Pyrethroid insecticide resistance in Anopheles gambiae sensu stricto is a major concern to malaria vector control programmes. Resistance mainly due target-site insensitivity arising from single point mutation, often referred as knockdown (kdr). Metabolic-based mechanisms have also been implicated pyrethroid East Africa and are currently being investigated West Africa. Here we report the co-occurrence of both population An. s.s. Nigeria. Bioassay, synergist biochemical analysis carried out on...
The evolution of insecticide resistance in mosquitoes is threatening the effectiveness and sustainability malaria control programs various parts world. Through their unique mode action, entomopathogenic fungi provide promising alternatives to chemical control. However, potential interactions between fungal infection resistance, such as cross-resistance, have not been investigated. We show that insecticide-resistant Anopheles remain susceptible with fungus Beauveria bassiana. Four different...
Abstract Background The continued spread of insecticide resistance in mosquito vectors malaria and arboviral diseases may lead to operational failure insecticide-based interventions if is not monitored managed efficiently. This study aimed develop validate a new WHO glass bottle bioassay method as an alternative the standard tube test monitor susceptibility public health insecticides with particular modes action, physical properties or both. Methods A multi-centre involving 21 laboratories...
Substitutions of a conserved alanine residue in the Rdl locus coding for gamma-aminobutyric acid (GABA) receptor subunit with serine or glycine confer resistance to dieldrin various insect species. Here, we show that substitution malaria vector, Anopheles gambiae, is genetically linked dieldrin. An developed independently resistant strain An. arabiensis. allele-specific polymerase chain reaction (PCR) assay was able differentiate and susceptible mosquitoes.
The malaria control programme of KwaZulu-Natal Province, South Africa, includes Mamfene and Mlambo communities. Western-type houses there are currently sprayed with deltamethrin, whereas traditional DDT for control. In 2002, mosquitoes the Anopheles gambiae complex (Diptera: Culicidae) were collected from DDT-sprayed houses, by window exit traps, man-baited nets outdoors. Larval collections also carried out at Mzinweni Pan near Mlambo. Species An. identified rDNA polymerase chain reaction...
Abstract Anopheles funestus Giles is one of the major African malaria vectors. It has previously been implicated in a outbreak KwaZulu/Natal, South Africa, during period 1996 to 2000. The re‐emergence this vector was associated with monooxygenase‐based resistance pyrethroid insecticides. We have identified gene from monooxygenase CYP6 family, CYP6P9, which over expressed resistant strain originating Mozambique. Quantitative Real‐Time PCR shows that highly egg and adult stages relative...
Anopheles arabiensis is the major vector of malaria in Ethiopia. Malaria control Ethiopia based on selective indoor residual spraying using DDT, distribution long lasting insecticide treated nets and environmental management larval breeding habitats. DDT pyrethroid insecticides are neurotoxins have a similar mode action sodium ion channel insects. It was therefore necessary to verify susceptibility status An. arabiensis, better understand cross-resistance between pyrethroids this species as...
Rapidly emerging insecticide resistance is creating an urgent need for new active ingredients to control the adult mosquitoes that vector malaria. Biopesticides based on spores of entomopathogenic fungi have shown considerable promise by causing very substantial mortality within 7–14 days exposure. This will generate excellent malaria if there a high likelihood contact early in their lives. However, where rates are lower, as might result from poor pesticide coverage, some one or more feeding...
Significance Conventional mosquito-control methods are becoming less effective in controlling mosquito-borne diseases because of widespread resistance against safe and recommended public health insecticides. Therefore innovative alternatives urgently needed. We present a novel method for exposing mosquitoes to insecticides that uses electrostatic forces bind insecticide particles. Results show this increases exposure such an extent even those have developed high levels can be killed...
Abstract South Africa aims to eliminate malaria within its borders by 2018. Despite well-coordinated provincial vector control programmes that are based on indoor residual insecticide spraying, low-level transmission continues in the low-altitude border regions of north-eastern sector country. In order identify underlying causes transmission, an enhanced surveillance system has been implemented at selected sites Mpumalanga and KwaZulu-Natal (KZN) provinces. The collection periods for data...
Two mitochondrial DNA clades have been described in Anopheles funestus populations from southern Africa. Clade I is common across the continent while clade II known only Mozambique and Madagascar. The specific biological status of these at present unknown. We investigated possible role that each might play transmission Plasmodium falciparum insecticide resistance An. Zimbabwe Zambia.Mosquitoes were collected inside houses Nchelenge District, Zambia Honde Valley, 2013 2014. WHO susceptibility...
Oxidative stress plays numerous biological roles, both functional and pathological. The role of oxidative in various epidemiologically relevant traits Anopheles mosquitoes is not well established. In this study, the effects on longevity insecticide resistance phenotype major malaria vector species An. arabiensis funestus were examined. Responses to dietary copper sulphate hydrogen peroxide used as proxies for by determining effect lethal dose. Glutathione peroxidase catalase activities...
Anopheles arabiensis is a major malaria vector in Africa. Adult females are likely to imbibe multiple blood meals during their lifetime. This results regular exposure potential toxins and blood-meal induced oxidative stress. Defence responses these stressors may affect other factors of epidemiological significance, such as insecticide resistance longevity. The aims this study were examine the effect blood-feeding on tolerance/resistance with increasing age, assess underlying biochemical...
With a sustained national malaria incidence of fewer than one case per 1000 population at risk, in 2012 South Africa officially transitioned from controlling to the ambitious goal eliminating within its borders by 2018. This review assesses progress made 3 years since programme re-orientation while highlighting challenges and suggesting priorities for moving towards elimination.National data annual spray coverage 2010 until 2014 were assessed trends. Information on surveillance, monitoring...
Temperature plays a crucial role in the life history of insects. Recent climate change research has highlighted importance elevated temperature on malaria vector distribution. This study aims to examine temperatures epidemiologically important life-history traits major vector, Anopheles arabiensis. Specifically, differential effects insecticide-resistant and susceptible strains were examined. Two laboratory A. arabiensis, insecticide-susceptible SENN DDT strains, used effect larval...
Abstract The gut microbiota of mosquitoes is a crucial determinant their fitness. As such, the biology Anopheles arabiensis , major malaria vector Southern Africa, was investigated. Two laboratory strains An. were used; SENN, an insecticide susceptible strain, and SENN-DDT, resistant strain. supplemented with either non-commensal bacteria or antibiotics via sucrose source to sterilize gut. fed broad-spectrum bactericidal antibiotic gentamicin, preferentially gram-positive (vancomycin),...
Abstract Background Insecticide resistance can present a major obstacle to malaria control programmes. Following the recent detection of DDT in Anopheles arabiensis Gokwe, Zimbabwe, underlying mechanisms this population were studied. Methods Standard WHO bioassays, using 0.75% permethrin, 4% DDT, 5% malathion, 0.1% bendiocarb and dieldrin performed on wild-collected adult anopheline mosquitoes F 1 progeny An. reared from wild-caught females. Molecular techniques used for species...
Indoor-resting anopheline mosquitoes were collected from Obuasi, Ghana, and identified morphologically by PCR as Anopheles funestus Giles. Wild-caught females induced to lay eggs. Samples of F1 progeny each family divided into cohorts either exposed DDT permethrin or stored for biochemical analysis. Bioassay data show evidence pyrethroid resistance in the parent A. population. The sodium channel gene survivors DDT-susceptible individuals was amplified sequenced determine whether any kdr-type...
Anopheles arabiensis is a major malaria vector in Africa. It thrives agricultural areas and has been associated with increased incidence under rice maize cultivation. This effect may be due to adult size abundance as consequence of optimal larval nutrition. The aim this study was examine the nutrition on life history expression insecticide resistance adults laboratory reared An. arabiensis. Larvae drawn from an susceptible strain (SENN) well DDT-resistant (SENN-DDT) were subjected three...
Insecticide resistance carries the potential to undermine efficacy of insecticide based malaria vector control strategies. Therefore, there is an urgent need for new insecticidal compounds. Black pepper (dried fruit from vine, Piper nigrum), used as a food additive and spice, its principal alkaloid piperine, have previously been shown larvicidal properties. The aim this study was investigate effects ground black piperine against third fourth instar Anopheles larvae drawn several...
Abstract A mutation in the second transmembrane domain of GABA receptor subunit, Rdl, is associated with resistance to insecticides such as dieldrin and fipronil. Molecular cloning Rdl cDNA from a strain malaria mosquito, Anopheles gambiae , which highly resistant revealed this (A296G) well another third (T345M). Wild‐type, A296G, T345M A296G + homomultimeric were expressed Xenopus laevis oocytes their sensitivities fipronil, deltamethrin, 1,1,1‐trichloro‐2,2‐bis(p‐chlorophenyl) ethane ( DDT...