Last data update: Nov 04, 2024. (Total: 48056 publications since 2009)
Records 1-16 (of 16 Records) |
Query Trace: Dada D[original query] |
---|
Vaccine effectiveness against anal HPV among men who have sex with men aged 18-45 years attending sexual health clinics in three United States cities, 2018-2023
DeSisto CL , Winer RL , Querec TD , Dada D , Pathela P , Asbel L , Lin J , Tang J , Iqbal A , Meites E , Unger ER , Markowitz LE . J Infect Dis 2024 BACKGROUND: We assessed human papillomavirus (HPV) vaccine effectiveness (VE) against anal HPV among men who have sex with men (MSM) in 2018-2023. METHODS: Residual anal specimens from MSM without HIV ages 18-45 years were tested for HPV. We calculated adjusted prevalence ratios (aPR) and 95% confidence intervals (CI) for associations between vaccination (≥1 dose) and quadrivalent vaccine (4vHPV)-type prevalence adjusting for city, race/ethnicity, and non-vaccine-type HPV prevalence, stratified by age group (18-26, 27-45). VE was calculated as (1-aPR)x100. RESULTS: Among 2802 persons aged 18-26, 4vHPV-type prevalence was lower in those vaccinated at age <18 (aPR=0.13, CI: 0.08-0.22, VE=87%) and those vaccinated ≥2 years before specimen collection (aPR=0.52, CI: 0.42-0.64, VE=48%), compared with unvaccinated persons. Among 3548 persons aged 27-45, 4vHPV-type prevalence was lower in those vaccinated at ages 18-26 (aPR=0.68, CI: 0.57-0.82, VE=32%) and those vaccinated ≥2 years before specimen collection (aPR=0.66, CI: 0.57-0.77, VE=33%), compared with unvaccinated persons. While we observed no VE in persons vaccinated at age >26 overall, 4vHPV-type prevalence was lower in the subgroup vaccinated ≥2 years before specimen collection (aPR=0.71, CI: 0.56-0.89, VE=29%). CONCLUSIONS: We found high VE against anal 4vHPV-type prevalence among MSM aged 18-26 who were vaccinated at age <18. Lower VE was observed among MSM ages 27-45 who were vaccinated at age 18-26 or ≥2 years before specimen collection. While ideally vaccination should be given at younger ages, vaccination can prevent some future infections in this population. |
Key gene modules and hub genes associated with pyrethroid and organophosphate resistance in Anopheles mosquitoes: a systems biology approach
Odhiambo CA , Derilus D , Impoinvil LM , Omoke D , Saizonou H , Okeyo S , Dada N , Mulder N , Nyamai D , Nyanjom S , Lenhart A , Djogbénou LS , Ochomo E . BMC Genomics 2024 25 (1) 665 Indoor residual spraying (IRS) and insecticide-treated nets (ITNs) are the main methods used to control mosquito populations for malaria prevention. The efficacy of these strategies is threatened by the spread of insecticide resistance (IR), limiting the success of malaria control. Studies of the genetic evolution leading to insecticide resistance could enable the identification of molecular markers that can be used for IR surveillance and an improved understanding of the molecular mechanisms associated with IR. This study used a weighted gene co-expression network analysis (WGCNA) algorithm, a systems biology approach, to identify genes with similar co-expression patterns (modules) and hub genes that are potential molecular markers for insecticide resistance surveillance in Kenya and Benin. A total of 20 and 26 gene co-expression modules were identified via average linkage hierarchical clustering from Anopheles arabiensis and An. gambiae, respectively, and hub genes (highly connected genes) were identified within each module. Three specific genes stood out: serine protease, E3 ubiquitin-protein ligase, and cuticular proteins, which were top hub genes in both species and could serve as potential markers and targets for monitoring IR in these malaria vectors. In addition to the identified markers, we explored molecular mechanisms using enrichment maps that revealed a complex process involving multiple steps, from odorant binding and neuronal signaling to cellular responses, immune modulation, cellular metabolism, and gene regulation. Incorporation of these dynamics into the development of new insecticides and the tracking of insecticide resistance could improve the sustainable and cost-effective deployment of interventions. |
Human-aided dispersal and population bottlenecks facilitate parasitism escape in the most invasive mosquito species
Girard M , Martin E , Vallon L , Tran Van V , Da Silva Carvalho C , Sack J , Bontemps Z , Balteneck J , Colin F , Duval P , Malassigné S , Hennessee I , Vizcaino L , Romer Y , Dada N , Ly Huynh Kim K , Huynh Thi Thuy T , Bellet C , Lambert G , Nantenaina Raharimalala F , Jupatanakul N , Goubert C , Boulesteix M , Mavingui P , Desouhant E , Luis P , Cazabet R , Hay AE , Valiente Moro C , Minard G . PNAS Nexus 2024 3 (5) pgae175 During biological invasion process, species encounter new environments and partially escape some ecological constraints they faced in their native range, while they face new ones. The Asian tiger mosquito Aedes albopictus is one of the most iconic invasive species introduced in every inhabited continent due to international trade. It has also been shown to be infected by a prevalent yet disregarded microbial entomoparasite Ascogregarina taiwanensis. In this study, we aimed at deciphering the factors that shape the global dynamics of A. taiwanensis infection in natural A. albopictus populations. We showed that A. albopictus populations are highly colonized by several parasite genotypes but recently introduced ones are escaping it. We further performed experiments based on the invasion process to explain such pattern. To that end, we hypothesized that (i) mosquito passive dispersal (i.e. human-aided egg transportation) may affect the parasite infectiveness, (ii) founder effects (i.e. population establishment by a small number of mosquitoes) may influence the parasite dynamics, and (iii) unparasitized mosquitoes are more prompt to found new populations through active flight dispersal. The two first hypotheses were supported as we showed that parasite infection decreases over time when dry eggs are stored and that experimental increase in mosquitoes' density improves the parasite horizontal transmission to larvae. Surprisingly, parasitized mosquitoes tend to be more active than their unparasitized relatives. Finally, this study highlights the importance of global trade as a driver of biological invasion of the most invasive arthropod vector species. |
Transcriptomic analysis of Anopheles gambiae from Benin reveals overexpression of salivary and cuticular proteins associated with cross-resistance to pyrethroids and organophosphates
Saizonou H , Impoinvil LM , Derilus D , Omoke D , Okeyo S , Dada N , Corredor C , Mulder N , Lenhart A , Ochomo E , Djogbénou LS . BMC Genomics 2024 25 (1) 348 BACKGROUND: Insecticide resistance (IR) is one of the major threats to malaria vector control programs in endemic countries. However, the mechanisms underlying IR are poorly understood. Thus, investigating gene expression patterns related to IR can offer important insights into the molecular basis of IR in mosquitoes. In this study, RNA-Seq was used to characterize gene expression in Anopheles gambiae surviving exposure to pyrethroids (deltamethrin, alphacypermethrin) and an organophosphate (pirimiphos-methyl). RESULTS: Larvae of An. gambiae s.s. collected from Bassila and Djougou in Benin were reared to adulthood and phenotyped for IR using a modified CDC intensity bottle bioassay. The results showed that mosquitoes from Djougou were more resistant to pyrethroids (5X deltamethrin: 51.7% mortality; 2X alphacypermethrin: 47.4%) than Bassila (1X deltamethrin: 70.7%; 1X alphacypermethrin: 77.7%), while the latter were more resistant to pirimiphos-methyl (1.5X: 48.3% in Bassila and 1X: 21.5% in Djougou). RNA-seq was then conducted on resistant mosquitoes, non-exposed mosquitoes from the same locations and the laboratory-susceptible An. gambiae s.s. Kisumu strain. The results showed overexpression of detoxification genes, including cytochrome P450s (CYP12F2, CYP12F3, CYP4H15, CYP4H17, CYP6Z3, CYP9K1, CYP4G16, and CYP4D17), carboxylesterase genes (COEJHE5E, COE22933) and glutathione S-transferases (GSTE2 and GSTMS3) in all three resistant mosquito groups analyzed. Genes encoding cuticular proteins (CPR130, CPR10, CPR15, CPR16, CPR127, CPAP3-C, CPAP3-B, and CPR76) were also overexpressed in all the resistant groups, indicating their potential role in cross resistance in An. gambiae. Salivary gland protein genes related to 'salivary cysteine-rich peptide' and 'salivary secreted mucin 3' were also over-expressed and shared across all resistant groups. CONCLUSION: Our results suggest that in addition to metabolic enzymes, cuticular and salivary gland proteins could play an important role in cross-resistance to multiple classes of insecticides in Benin. These genes warrant further investigation to validate their functional role in An. gambiae resistance to insecticides. |
Whole transcriptomic analysis reveals overexpression of salivary gland and cuticular proteins genes in insecticide-resistant Anopheles arabiensis from Western Kenya
Omoke D , Impoinvil LM , Derilus D , Okeyo S , Saizonou H , Mulder N , Dada N , Lenhart A , Djogbénou L , Ochomo E . BMC Genomics 2024 25 (1) 313 BACKGROUND: Effective vector control is key to malaria prevention. However, this is now compromised by increased insecticide resistance due to continued reliance on insecticide-based control interventions. In Kenya, we have observed heterogenous resistance to pyrethroids and organophosphates in Anopheles arabiensis which is one of the most widespread malaria vectors in the country. We investigated the gene expression profiles of insecticide resistant An. arabiensis populations from Migori and Siaya counties in Western Kenya using RNA-Sequencing. Centers for Disease Control and Prevention (CDC) bottle assays were conducted using deltamethrin (DELTA), alphacypermethrin (ACYP) and pirimiphos-methyl (PMM) to determine the resistance status in both sites. RESULTS: Mosquitoes from Migori had average mortalities of 91%, 92% and 58% while those from Siaya had 85%, 86%, and 30% when exposed to DELTA, ACYP and PMM, respectively. RNA-Seq analysis was done on pools of mosquitoes which survived exposure ('resistant'), mosquitoes that were not exposed, and the insecticide-susceptible An. arabiensis Dongola strain. Gene expression profiles of resistant mosquitoes from both Migori and Siaya showed an overexpression mainly of salivary gland proteins belonging to both the short and long form D7 genes, and cuticular proteins (including CPR9, CPR10, CPR15, CPR16). Additionally, the overexpression of detoxification genes including cytochrome P450s (CYP9M1, CYP325H1, CYP4C27, CYP9L1 and CYP307A1), 2 carboxylesterases and a glutathione-S-transferase (GSTE4) were also shared between DELTA, ACYP, and PMM survivors, pointing to potential contribution to cross resistance to both pyrethroid and organophosphate insecticides. CONCLUSION: This study provides novel insights into the molecular basis of insecticide resistance in An. arabiensis in Western Kenya and suggests that salivary gland proteins and cuticular proteins are associated with resistance to multiple classes of insecticides. |
Western Kenyan Anopheles gambiae s.s. showing intense permethrin resistance harbor distinct microbiota (preprint)
Omoke D , Kipsum M , Otieno S , Esalimba E , Sheth M , Lenhart A , Njeru EM , Ochomo E , Dada N . bioRxiv 2020 2020.11.12.378760 Background Insecticide resistance poses a growing challenge to malaria vector control in Kenya and around the world. Following evidence of associations between the mosquito microbiota and insecticide resistance, we comparatively characterized the microbiota of An. gambiae s.s. from Tulukuyi village, Bungoma, Kenya, with differing permethrin resistance profiles.Methods Using the CDC bottle bioassay, 133 2-3 day-old, virgin, non-blood fed female F1 progeny of field-caught An. gambiae s.s. were exposed to five times (107.5μg/ml) the discriminating dose of permethrin. Post bioassay, 50 resistant and 50 susceptible mosquitoes were subsequently screened for kdr East and West mutations, and individually processed for microbial analysis using high throughput sequencing targeting the universal bacterial and archaeal 16S rRNA gene.Results 47% of the samples tested (n=133) were resistant, and of the 100 selected for further processing, 99% were positive for kdr East and 1% for kdr West. Overall, 84 bacterial taxa were detected across all mosquito samples, with 36 of these shared between resistant and susceptible mosquitoes. A total of 20 were unique to the resistant mosquitoes and 28 were unique to the susceptible mosquitoes. There were significant differences in bacterial composition between resistant and susceptible individuals (F=2.33, P=0.001), with presence of Sphingobacterium, Lysinibacillus and Streptococcus (all known pyrethroid-degrading taxa), and the radiotolerant Rubrobacter, being significantly associated with resistant mosquitoes. On the other hand, the presence of Myxococcus, was significantly associated with susceptible mosquitoes.Conclusion This is the first report of distinct microbiota in An. gambiae s.s. associated with intense pyrethroid resistance. The findings highlight differentially abundant bacterial taxa between resistant and susceptible mosquitoes, and further suggest a microbe-mediated mechanism of insecticide resistance in mosquitoes. Our results also indicate fixation of the kdr East mutation in this mosquito population, precluding further analysis of its associations with the mosquito microbiota, but presenting the hypothesis that any microbe-mediated mechanism of insecticide resistance would be likely of a metabolic nature. Overall, this study lays initial groundwork for understanding microbe-mediated mechanisms of insecticide resistance in African malaria vectors, and potentially identifying novel microbial markers of insecticide resistance that could supplement existing vector surveillance tools.Competing Interest StatementThe authors have declared no competing interest. |
Geographic heterogeneity in Anopheles albimanus microbiota is lost within one generation of laboratory colonization (preprint)
Dada N , Benedict AC , López F , Lol JC , Sheth M , Dzuris N , Padilla N , Lenhart A . bioRxiv 2020 2020.06.02.129619 Research on mosquito-microbe interactions may lead to new tools for mosquito and mosquito-borne disease control. To date, such research has largely utilized laboratory-reared mosquitoes that may lack the microbial diversity of wild populations. To better understand how mosquito microbiota may vary across different geographic locations and upon laboratory colonization, we characterized the microbiota of F1 progeny of wild-caught adult Anopheles albimanus from four locations in Guatemala using high throughput 16S rRNA amplicon sequencing. A total of 132 late instar larvae and 135 2-5day old, non-blood-fed virgin adult females were reared under identical laboratory conditions, pooled (3 individuals/pool) and analyzed. Larvae from mothers collected at different sites showed different microbial compositions (p=0.001; F = 9.5), but these differences were no longer present at the adult stage (p=0.12; F = 1.6). This indicates that mosquitoes retain a significant portion of their field-derived microbiota throughout immature development but shed them before or during adult eclosion. This is the first time the microbiota of F1 progeny of wild-caught mosquitoes has been characterized in relation to parental collection site, and our findings provide evidence that geographically associated heterogeneity in microbiota composition persists for a single generation, but only until the end of the larval stage. These findings advance our understanding of how the mosquito microbiota is altered upon first laboratory colonization, and raises considerations for how mosquito microbiome research may be extended beyond the laboratory to field settings.Competing Interest StatementThe authors have declared no competing interest. |
Pyrethroid exposure alters Anopheles albimanus microbiota and resistant mosquitoes harbor more insecticide-metabolizing bacteria (preprint)
Dada N , Lol JC , Benedict AC , Lopez F , Sheth M , Dzuris N , Padilla N , Lenhart A . bioRxiv 2019 537480 A deeper understanding of the mechanisms underlying insecticide resistance is needed to mitigate its threat to malaria vector control. Building upon our earlier identified associations between mosquito microbiota and insecticide resistance, we demonstrate for the first time, type-specific effects of pyrethroid exposure on internal and cuticle surface bacteria in adult progeny of field-collected Anopheles albimanus. In contrast, larval cuticle surface—but not internal—bacteria were affected by pyrethroid exposure. Being over five-folds more abundant in pyrethroid resistant adults, as compared to susceptible or non-insecticide-exposed mosquitoes, Klebsiella (alphacypermethrin), Pantoea and Asaia (permethrin) were identified as potential markers of pyrethroid resistance in An. albimanus. We also show for the first time that An. albimanus larvae and adult cuticles harbor more diverse bacterial communities than their internal microbial niches. Our findings indicate insecticide selection pressures on mosquito microbiota, and support the hypothesis of an undescribed microbe-mediated mechanism of insecticide metabolism in mosquitoes. |
Human-aided dispersal facilitates parasitism escape in the most invasive mosquito species (preprint)
Girard M , Martin E , Vallon L , Van VT , Da Silva Carvalho C , Sacks J , Bontemps Z , Balteneck J , Colin F , Duval P , Malassigne S , Swanson J , Hennessee I , Jiang S , Vizcaino L , Romer Y , Dada N , Huynh Kim KL , Thi Thuy TH , Bellet C , Lambert G , Raharimalala FN , Jupatanakul N , Goubert C , Boulesteix M , Mavingui P , Desouhant E , Luis P , Cazabet R , Hay AE , Moro CV , Minard G . bioRxiv 2023 20 Human-aided invasion of alien species across the world sometimes leads to economic, health or environmental burdens. During invasion process, species encounter new environments and partially escape some ecological constrains they faced in their native range, while they face new ones. The Asian tiger mosquito Aedes albopictus is one of the most iconic invasive species that was introduced in every inhabited continent over a short period of time due to international trade. It has also been shown to be infected by a prevalent and yet disregarded gregarine entomoparasite Ascogregarina taiwanensis. In this study, we aimed at deciphering the global dynamics of As. taiwanensis infection in natural Ae. albopictus populations and we further explored factors shaping its distribution. We showed that Ae. albopictus populations are highly colonized by several As. taiwanesis genotypes but recently introduced ones are escaping the parasite. We further performed experiments to explain such pattern. First, we hypothesized that founder effects (i.e. population establishment by a small number of individuals) may influence the parasite dynamics. This was confirmed since experimental increase in mosquitoes' density improves the parasite horizontal transmission to larvae. Furthermore, Ae. albopictus larvae do not exhibit density dependent prophylaxis to control the parasite meaning that infection is not mitigated when larval density increases. Secondly, we hypothesized that unparasitized mosquitoes were more prompt to found new populations through active flight dispersal. This was, however, unlikely since parasitized mosquitoes tend to be more active than their unparasitized relatives. Finally, we hypothesized that mosquito passive dispersal (i.e. often mediated by human-aided transportation of dried eggs) affects the parasite infectiveness. Our results support this hypothesis since parasite infection decreases over time when dry eggs are stored. This study highlights the importance of global trade on parasitism escape in one of the most invasive vector species on earth. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license. |
Assessing the effect of electronic health information exchange on the completeness and validity of data for measuring viral load testing turnaround time in Nigeria
Aniekwe C , Cuffe K , Audu I , Nalda N , Ibezim B , Nnakwe M , Anazodo T , Dada M , Rottinghaus Romano E , Okoye M , Martin M , Shrivastava R . Int J Med Inform 2023 174 105059 INTRODUCTION: Implementation of health information exchange has been shown to result in several benefits which includes the improvement in the completeness and timeliness of data for public health program monitoring and surveillance. OBJECTIVE: The objective of this study was to assess the effect of implementing an electronic health information exchange (HIE) on the quality of data available to measure HIV viral load testing turnaround time (TAT) in Nigeria. METHODS: We measured viral load data validity and completeness before the implementation of electronic health information exchange, and 6 months after implementation. Records of specimens collected at 30 healthcare facilities and tested in 3 Polymerase Chain Reaction (PCR) labs were analyzed. We define data completeness as the percentage of non-missing values and measured this value by specimens and by data elements in the dataset for calculating TAT. To examine data validity, we classified TAT segments with negative values and date fields that were not in International Organization for Standardization(ISO) standard date format as invalid. Validity was measured by specimens and by each TAT segment. Pearson's chi square was used to assess for improvements in validity and completeness post implementation of HIE. RESULTS: 15,226 records of specimens were analyzed at baseline and 18,022 records of specimens analyzed at endline. Data completeness for all specimens recorded increased significantly from 47% before HIE implementation to 67% six months after implementation (p < 0.01). Data validity also increased from 90% before implementation to 91% after implementation (p < 0.01) CONCLUSION: Our study demonstrated evidence of significant improvement in the quality of data available to measure viral load turnaround time with the implementation of HIE. |
Comprehensive characterization of internal and cuticle surface microbiota of laboratory-reared F Anopheles albimanus originating from different sites.
Dada N , Benedict AC , López F , Lol JC , Sheth M , Dzuris N , Padilla N , Lenhart A . Malar J 2021 20 (1) 414 BACKGROUND: Research on mosquito-microbe interactions may lead to new tools for mosquito and mosquito-borne disease control. To date, such research has largely utilized laboratory-reared mosquitoes that typically lack the microbial diversity of wild populations. A logical progression in this area involves working under controlled settings using field-collected mosquitoes or, in most cases, their progeny. Thus, an understanding of how laboratory colonization affects the assemblage of mosquito microbiota would aid in advancing mosquito microbiome studies and their applications beyond laboratory settings. METHODS: Using high throughput 16S rRNA amplicon sequencing, the internal and cuticle surface microbiota of F(1) progeny of wild-caught adult Anopheles albimanus from four locations in Guatemala were characterized. A total of 132 late instar larvae and 135 2-5 day-old, non-blood-fed virgin adult females that were reared under identical laboratory conditions, were pooled (3 individuals/pool) and analysed. RESULTS: Results showed location-associated heterogeneity in both F(1) larval internal (p = 0.001; pseudo-F = 9.53) and cuticle surface (p = 0.001; pseudo-F = 8.51) microbiota, and only F(1) adult cuticle surface (p = 0.001; pseudo-F = 4.5) microbiota, with a more homogenous adult internal microbiota (p = 0.12; pseudo-F = 1.6) across collection sites. Overall, ASVs assigned to Leucobacter, Thorsellia, Chryseobacterium and uncharacterized Enterobacteriaceae, dominated F(1) larval internal microbiota, while Acidovorax, Paucibacter, and uncharacterized Comamonadaceae, dominated the larval cuticle surface. F(1) adults comprised a less diverse microbiota compared to larvae, with ASVs assigned to the genus Asaia dominating both internal and cuticle surface microbiota, and constituting at least 70% of taxa in each microbial niche. CONCLUSIONS: These results suggest that location-specific heterogeneity in filed mosquito microbiota can be transferred to F(1) progeny under normal laboratory conditions, but this may not last beyond the F(1) larval stage without adjustments to maintain field-derived microbiota. These findings provide the first comprehensive characterization of laboratory-colonized F(1) An. albimanus progeny from field-derived mothers. This provides a background for studying how parentage and environmental conditions differentially or concomitantly affect mosquito microbiome composition, and how this can be exploited in advancing mosquito microbiome studies and their applications beyond laboratory settings. |
Integrated disease management: arboviral infections and waterborne diarrhoea
Overgaard HJ , Dada N , Lenhart A , Stenström TAB , Alexander N . Bull World Health Organ 2021 99 (8) 583-592 Water-related diseases such as diarrhoeal diseases from viral, bacterial and parasitic organisms and Aedes-borne arboviral diseases are major global health problems. We believe that these two disease groups share common risk factors, namely inadequate household water management, poor sanitation and solid waste management. Where water provision is inadequate, water storage is essential. Aedes mosquitoes commonly breed in household water storage containers, which can hold water contaminated with enteric disease-causing organisms. Microbiological contamination of water between source and point-of-use is a major cause of reduced drinking-water quality. Inadequate sanitation and solid waste management increase not only risk of water contamination, but also the availability of mosquito larval habitats. In this article we discuss integrated interventions that interrupt mosquito breeding while also providing sanitary environments and clean water. Specific interventions include improving storage container design, placement and maintenance and scaling up access to piped water. Vector control can be integrated into sanitation projects that target sewers and drains to avoid accumulation of stagnant water. Better management of garbage and solid waste can reduce the availability of mosquito habitats while improving human living conditions. Our proposed integration of disease interventions is consistent with strategies promoted in several global health frameworks, such as the sustainable development goals, the global vector control response, behavioural change, and water, sanitation and hygiene initiatives. Future research should address how interventions targeting water, sanitation, hygiene and community waste disposal also benefit Aedes-borne disease control. The projected effects of climate change mean that integrated management and control strategies will become increasingly important. |
Western Kenyan Anopheles gambiae showing intense permethrin resistance harbour distinct microbiota.
Omoke D , Kipsum M , Otieno S , Esalimba E , Sheth M , Lenhart A , Njeru EM , Ochomo E , Dada N . Malar J 2021 20 (1) 77 BACKGROUND: Insecticide resistance poses a growing challenge to malaria vector control in Kenya and around the world. Following evidence of associations between the mosquito microbiota and insecticide resistance, the microbiota of Anopheles gambiae sensu stricto (s.s.) from Tulukuyi village, Bungoma, Kenya, with differing permethrin resistance profiles were comparatively characterized. METHODS: Using the CDC bottle bioassay, 133 2-3 day-old, virgin, non-blood fed female F(1) progeny of field-caught An. gambiae s.s. were exposed to five times (107.5 µg/ml) the discriminating dose of permethrin. Post bioassay, 50 resistant and 50 susceptible mosquitoes were subsequently screened for kdr East and West mutations, and individually processed for microbial analysis using high throughput sequencing targeting the universal bacterial and archaeal 16S rRNA gene. RESULTS: 47 % of the samples tested (n = 133) were resistant, and of the 100 selected for further processing, 99 % were positive for kdr East and 1 % for kdr West. Overall, 84 bacterial taxa were detected across all mosquito samples, with 36 of these shared between resistant and susceptible mosquitoes. A total of 20 bacterial taxa were unique to the resistant mosquitoes and 28 were unique to the susceptible mosquitoes. There were significant differences in bacterial composition between resistant and susceptible individuals (PERMANOVA, pseudo-F = 2.33, P = 0.001), with presence of Sphingobacterium, Lysinibacillus and Streptococcus (all known pyrethroid-degrading taxa), and the radiotolerant Rubrobacter, being significantly associated with resistant mosquitoes. On the other hand, the presence of Myxococcus, was significantly associated with susceptible mosquitoes. CONCLUSIONS: This is the first report of distinct microbiota in An. gambiae s.s. associated with intense pyrethroid resistance. The findings highlight differentially abundant bacterial taxa between resistant and susceptible mosquitoes, and further suggest a microbe-mediated mechanism of insecticide resistance in mosquitoes. These results also indicate fixation of the kdr East mutation in this mosquito population, precluding further analysis of its associations with the mosquito microbiota, but presenting the hypothesis that any microbe-mediated mechanism of insecticide resistance would be likely of a metabolic nature. Overall, this study lays initial groundwork for understanding microbe-mediated mechanisms of insecticide resistance in African mosquito vectors of malaria, and potentially identifying novel microbial markers of insecticide resistance that could supplement existing vector surveillance tools. |
Sex differences in HIV testing - 20 PEPFAR-supported sub-Saharan African Countries, 2019
Drammeh B , Medley A , Dale H , De AK , Diekman S , Yee R , Aholou T , Lasry A , Auld A , Baack B , Duffus W , Shahul E , Wong V , Grillo M , Al-Samarrai T , Ally S , Nyangulu M , Nyirenda R , Olivier J , Chidarikire T , Khanyile N , Kayange AA , Rwabiyago OE , Kategile U , Bisimba J , Weber RA , Ncube G , Maguwu O , Pietersen I , Mali D , Dzinotyiweyi E , Nelson L , Bosco MJ , Dalsone K , Apolot M , Anangwe S , Soo LK , Mugambi M , Mbayiha A , Mugwaneza P , Malamba SS , Phiri A , Chisenga T , Boyd M , Temesgan C , Shimelis M , Weldegebreal T , Getachew M , Balachandra S , Eboi E , Shasha W , Doumatey N , Adjoua D , Meribe C , Gwamna J , Gado P , John-Dada I , Mukinda E , Lukusa LFK , Kalenga L , Bunga S , Achyut V , Mondi J , Loeto P , Mogomotsi G , Ledikwe J , Ramphalla P , Tlhomola M , Mirembe JK , Nkwoh T , Eno L , Bonono L , Honwana N , Chicuecue N , Simbine A , Malimane I , Dube L , Mirira M , Mndzebele P , Frawley A , Cardo YMR , Behel S . MMWR Morb Mortal Wkly Rep 2020 69 (48) 1801-1806 Despite progress toward controlling the human immunodeficiency virus (HIV) epidemic, testing gaps remain, particularly among men and young persons in sub-Saharan Africa (1). This observational study used routinely collected programmatic data from 20 African countries reported to the U.S. President's Emergency Plan for AIDS Relief (PEPFAR) from October 2018 to September 2019 to assess HIV testing coverage and case finding among adults (defined as persons aged ≥15 years). Indicators included number of HIV tests conducted, number of HIV-positive test results, and percentage positivity rate. Overall, the majority of countries reported higher HIV case finding among women than among men. However, a slightly higher percentage positivity was recorded among men (4.7%) than among women (4.1%). Provider-initiated counseling and testing (PITC) in health facilities identified approximately two thirds of all new cases, but index testing had the highest percentage positivity in all countries among both sexes. Yields from voluntary counseling and testing (VCT) and mobile testing varied by sex and by country. These findings highlight the need to identify and implement the most efficient strategies for HIV case finding in these countries to close coverage gaps. Strategies might need to be tailored for men who remain underrepresented in the majority of HIV testing programs. |
Pyrethroid exposure alters internal and cuticle surface bacterial communities in Anopheles albimanus.
Dada N , Lol JC , Benedict AC , Lopez F , Sheth M , Dzuris N , Padilla N , Lenhart A . ISME J 2019 13 (10) 2447-2464 A deeper understanding of the mechanisms underlying insecticide resistance is needed to mitigate its threat to malaria vector control. Following previously identified associations between mosquito microbiota and insecticide resistance, we demonstrate for the first time, the effects of pyrethroid exposure on the microbiota of F1 progeny of field-collected Anopheles albimanus. Larval and adult mosquitoes were exposed to the pyrethroids alphacypermethrin (only adults), permethrin, and deltamethrin. While there were no significant differences in bacterial composition between insecticide-resistant and insecticide-susceptible mosquitoes, bacterial composition between insecticide-exposed and non-exposed mosquitoes was significantly different for alphacypermethrin and permethrin exposure. Along with other bacterial taxa not identified to species, Pantoea agglomerans (a known insecticide-degrading bacterial species) and Pseudomonas fragi were more abundant in insecticide-exposed compared to non-exposed adults, demonstrating that insecticide exposure can alter mosquito bacterial communities. We also show for the first time that the cuticle surfaces of both larval and adult An. albimanus harbor more diverse bacterial communities than their internal microbial niches. Together, these findings demonstrate how insecticide pressure could be selecting for certain bacteria within mosquitoes, especially insecticide-metabolizing bacteria, thus potentially contributing to insecticide resistance. |
Whole metagenome sequencing reveals links between mosquito microbiota and insecticide resistance in malaria vectors.
Dada N , Sheth M , Liebman K , Pinto J , Lenhart A . Sci Rep 2018 8 (1) 2084 In light of the declining global malaria burden attained largely due to insecticides, a deeper understanding of the factors driving insecticide resistance is needed to mitigate its growing threat to malaria vector control programs. Following evidence of microbiota-mediated insecticide resistance in agricultural pests, we undertook a comparative study of the microbiota in mosquitoes of differing insecticide resistance status. The microbiota of wild-caught Anopheles albimanus, an important Latin American malaria vector, that were resistant (FEN_Res) or susceptible (FEN_Sus) to the organophosphate (OP) insecticide fenitrothion were characterized and compared using whole metagenome sequencing. Results showed differing composition of the microbiota and its functions between FEN_Res and FEN_Sus, with significant enrichment of OP-degrading bacteria and enzymes in FEN_Res compared to FEN_Sus. Lower bacterial diversity was observed in FEN_Res compared to FEN_Sus, suggesting the enrichment of bacterial taxa with a competitive advantage in response to insecticide selection pressure. We report and characterize for the first time whole metagenomes of An. albimanus, revealing associations between the microbiota and phenotypic resistance to the insecticide fenitrothion. This study lays the groundwork for further investigation of the role of the mosquito microbiota in insecticide resistance. |
- Page last reviewed:Feb 1, 2024
- Page last updated:Nov 04, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure