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Oboh MA, Morenikeji OB, Ojurongbe O, Thomas BN. Transcriptomic analyses of differentially expressed human genes, micro RNAs and long-non-coding RNAs in severe, symptomatic and asymptomatic malaria infection. Sci Rep 2024; 14:16901. [PMID: 39043812 PMCID: PMC11266512 DOI: 10.1038/s41598-024-67663-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 07/15/2024] [Indexed: 07/25/2024] Open
Abstract
Malaria transmission and endemicity in Africa remains hugely disproportionate compared to the rest of the world. The complex life cycle of P. falciparum (Pf) between the vertebrate human host and the anopheline vector results in differential expression of genes within and between hosts. An in-depth understanding of Pf interaction with various human genes through regulatory elements will pave way for identification of newer tools in the arsenal for malaria control. Therefore, the regulatory elements (REs) involved in the over- or under-expression of various host immune genes hold the key to elucidating alternative control measures that can be applied for disease surveillance, prompt diagnosis and treatment. We carried out an RNAseq analysis to identify differentially expressed genes and network elucidation of non-coding RNAs and target genes associated with immune response in individuals with different clinical outcomes. Raw RNAseq datasets, retrieved for analyses include individuals with severe (Gambia-20), symptomatic (Burkina Faso-15), asymptomatic (Mali-16) malaria as well as uninfected controls (Tanzania-20; Mali-36). Of the total 107 datasets retrieved, we identified 5534 differentially expressed genes (DEGs) among disease and control groups. A peculiar pattern of DEGs was observed, with individuals presenting with severe/symptomatic malaria having the highest and most diverse upregulated genes, while a reverse phenomenon was recorded among asymptomatic and uninfected individuals. In addition, we identified 141 differentially expressed micro RNA (miRNA), of which 78 and 63 were upregulated and downregulated respectively. Interactome analysis revealed a moderate interaction between DEGs and miRNAs. Of all identified miRNA, five were unique (hsa-mir-32, hsa-mir-25, hsa-mir-221, hsa-mir-29 and hsa-mir-148) because of their connectivity to several genes, including hsa-mir-221 connected to 16 genes. Six-hundred and eight differentially expressed long non coding RNA (lncRNA) were also identified, including SLC7A11, LINC01524 among the upregulated ones. Our study provides important insight into host immune genes undergoing differential expression under different malaria conditions. It also identified unique miRNAs and lncRNAs that modify and/or regulate the expression of various immune genes. These regulatory elements we surmise, have the potential to serve a diagnostic purpose in discriminating between individuals with severe/symptomatic malaria and those with asymptomatic infection or uninfected, following further clinical validation from field isolates.
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Affiliation(s)
- Mary A Oboh
- Department of Biomedical Sciences, Rochester Institute of Technology, 153 Lomb Memorial Drive, Rochester, NY, 14623, USA
| | - Olanrewaju B Morenikeji
- Division of Biological and Health Sciences, University of Pittsburgh Bradford, Bradford, PA, USA
| | - Olusola Ojurongbe
- Department of Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Bolaji N Thomas
- Department of Biomedical Sciences, Rochester Institute of Technology, 153 Lomb Memorial Drive, Rochester, NY, 14623, USA.
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2
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Ouédraogo A, Bougouma EC, Palacpac NMQ, Houard S, Nebie I, Sawadogo J, Berges GD, Soulama I, Diarra A, Hien D, Ouedraogo AZ, Konaté AT, Kouanda S, Myoui A, Ezoe S, Ishii KJ, Sato T, D’Alessio F, Leroy O, Tiono AB, Cousens S, Horii T, Sirima SB. Safety and immunogenicity of BK-SE36/CpG malaria vaccine in healthy Burkinabe adults and children: a phase 1b randomised, controlled, double-blinded, age de-escalation trial. Front Immunol 2023; 14:1267372. [PMID: 37908361 PMCID: PMC10613650 DOI: 10.3389/fimmu.2023.1267372] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/25/2023] [Indexed: 11/02/2023] Open
Abstract
Background BK-SE36/CpG is a recombinant blood-stage malaria vaccine candidate based on the N-terminal Plasmodium falciparum serine repeat antigen5 (SE36), adsorbed to aluminium hydroxide gel and reconstituted, prior to administration, with synthetic oligodeoxynucleotides bearing CpG motifs. In healthy Japanese adult males, BK-SE36/CpG was well tolerated. This study assessed its safety and immunogenicity in healthy malaria-exposed African adults and children. Methods A double-blind, randomised, controlled, age de-escalating clinical trial was conducted in an urban area of Ouagadougou, Burkina Faso. Healthy participants (n=135) aged 21-45 years (Cohort 1), 5-10 years (Cohort 2) and 12-24 months (Cohort 3) were randomised to receive three vaccine doses (Day 0, 28 and 112) of BK-SE36/CpG or rabies vaccine by intramuscular injection. Results One hundred thirty-four of 135 (99.2%) subjects received all three scheduled vaccine doses. Vaccinations were well tolerated with no related Grade 3 (severe) adverse events (AEs). Pain/limitation of limb movement, headache in adults and fever in younger children (all mild to moderate in intensity) were the most frequently observed local and systemic AEs. Eighty-three of BK-SE36/CpG (91%) recipients and 37 of control subjects (84%) had Grade 1/2 events within 28 days post vaccination. Events considered by the investigator to be vaccine related were experienced by 38% and 14% of subjects in BK-SE36/CpG and control arms, respectively. Throughout the trial, six Grade 3 events (in 4 subjects), not related to vaccination, were recorded in the BK-SE36/CpG arm: 5 events (in 3 subjects) within 28 days of vaccination. All serious adverse events (SAEs) (n=5) were due to severe malaria (52-226 days post vaccination) and not related to vaccination. In all cohorts, BK-SE36/CpG arm had higher antibody titres after Dose 3 than after Dose 2. Younger cohorts had stronger immune responses (12-24-month-old > 5-10 years-old > 21-45 years-old). Sera predominantly reacted to peptides that lie in intrinsically unstructured regions of SE36. In the control arm, there were no marked fold changes in antibody titres and participants' sera reacted poorly to all peptides spanning SE36. Conclusion BK-SE36/CpG was well-tolerated and immunogenic. These results pave the way for further proof-of-concept studies to demonstrate vaccine efficacy. Clinical trial registration https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=1921, PACTR201701001921166.
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Affiliation(s)
| | | | - Nirianne Marie Q. Palacpac
- Department of Malaria Vaccine Development, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Sophie Houard
- European Vaccine Initiative (EVI), Universitäts Klinikum Heidelberg, Heidelberg, Germany
| | - Issa Nebie
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Jean Sawadogo
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | | | - Issiaka Soulama
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Amidou Diarra
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Denise Hien
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | | | - Amadou T. Konaté
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Seni Kouanda
- Institut de Recherche en Sciences de la Santé, Ouagadougou, Burkina Faso
| | - Akira Myoui
- Medical Center for Translational Research, Osaka University Hospital, Suita, Japan
| | - Sachiko Ezoe
- Medical Center for Translational Research, Osaka University Hospital, Suita, Japan
- Department of Space Infection Control, Graduate School of Medicine, Division of Health Sciences, Osaka University, Osaka, Japan
| | - Ken J. Ishii
- Center for Vaccine and Adjuvant Research, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Japan
- Laboratory of Vaccine Science, Immunology Frontier Research Center, Osaka University, Suita, Japan
- Division of Vaccine Science, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Takanobu Sato
- Research and Development Division, Nobelpharma Co., Ltd., Tokyo, Japan
| | - Flavia D’Alessio
- European Vaccine Initiative (EVI), Universitäts Klinikum Heidelberg, Heidelberg, Germany
| | - Odile Leroy
- European Vaccine Initiative (EVI), Universitäts Klinikum Heidelberg, Heidelberg, Germany
| | - Alfred B. Tiono
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Simon Cousens
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine (LSHTM), London, United Kingdom
| | - Toshihiro Horii
- Department of Malaria Vaccine Development, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
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3
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Nardini L, Brito-Fravallo E, Campagne P, Pain A, Genève C, Vernick KD, Mitri C. The voltage-gated sodium channel, para, limits Anopheles coluzzii vector competence in a microbiota dependent manner. Sci Rep 2023; 13:14572. [PMID: 37666840 PMCID: PMC10477260 DOI: 10.1038/s41598-023-40432-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 08/10/2023] [Indexed: 09/06/2023] Open
Abstract
The voltage-gated sodium channel, para, is a target of DDT and pyrethroid class insecticides. Single nucleotide mutations in para, called knockdown resistant or kdr, which contribute to resistance against DDT and pyrethroid insecticides, have been correlated with increased susceptibility of Anopheles to the human malaria parasite Plasmodium falciparum. However, a direct role of para activity on Plasmodium infection has not yet been established. Here, using RNA-mediated silencing, we provide in vivo direct evidence for the requirement of wild-type (wt) para function for insecticide activity of deltamethrin. Depletion of wt para, which is susceptible to insecticide, causes deltamethrin tolerance, indicating that insecticide-resistant kdr alleles are likely phenocopies of loss of para function. We then show that normal para activity in An. coluzzii limits Plasmodium infection prevalence for both P. falciparum and P. berghei. A transcriptomic analysis revealed that para activity does not modulate the expression of immune genes. However, loss of para function led to enteric dysbiosis with a significant increase in the total bacterial abundance, and we show that para function limiting Plasmodium infection is microbiota dependent. In the context of the bidirectional "enteric microbiota-brain" axis studied in mammals, these results pave the way for studying whether the activity of the nervous system could control Anopheles vector competence.
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Affiliation(s)
- Luisa Nardini
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, CNRS, Institut Pasteur, UMR2000, Université de Paris, 75015, Paris, France
| | - Emma Brito-Fravallo
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, CNRS, Institut Pasteur, UMR2000, Université de Paris, 75015, Paris, France
| | - Pascal Campagne
- Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Université de Paris, 75015, Paris, France
| | - Adrien Pain
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, CNRS, Institut Pasteur, UMR2000, Université de Paris, 75015, Paris, France
| | - Corinne Genève
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, CNRS, Institut Pasteur, UMR2000, Université de Paris, 75015, Paris, France
| | - Kenneth D Vernick
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, CNRS, Institut Pasteur, UMR2000, Université de Paris, 75015, Paris, France
| | - Christian Mitri
- Genetics and Genomics of Insect Vectors Unit, Department of Parasites and Insect Vectors, CNRS, Institut Pasteur, UMR2000, Université de Paris, 75015, Paris, France.
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4
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Adams KL, Selland EK, Willett BC, Carew JW, Vidoudez C, Singh N, Catteruccia F. Selection for insecticide resistance can promote Plasmodium falciparum infection in Anopheles. PLoS Pathog 2023; 19:e1011448. [PMID: 37339122 DOI: 10.1371/journal.ppat.1011448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/29/2023] [Indexed: 06/22/2023] Open
Abstract
Insecticide resistance is under strong selective pressure in Anopheles mosquitoes due to widespread usage of insecticides in vector control strategies. Resistance mechanisms likely cause changes that profoundly affect mosquito physiology, yet it remains poorly understood how selective pressures imposed by insecticides may alter the ability of the mosquito to host and transmit a Plasmodium infection. From pyrethroid-resistant field-derived Anopheles gambiae s.l. mosquitoes, we established resistant (RES) and susceptible (SUS) colonies by either selection for, or loss of insecticide resistance. We show increased oocyst intensity and growth rate as well as increased sporozoite prevalence and intensity in RES compared to SUS females infected with Plasmodium falciparum. The increase in infection intensity in RES females was not associated with the presence of the kdrL1014F mutation and was not impacted by inhibition of Cytochrome P450s. The lipid transporter lipophorin (Lp), which was upregulated in RES compared to SUS, was at least partly implicated in the increased intensity of P. falciparum but not directly involved in the insecticide resistance phenotype. Interestingly, we observed that although P. falciparum infections were not affected when RES females were exposed to permethrin, these females had decreased lipid abundance in the fat body following exposure, pointing to a possible role for lipid mobilization in response to damage caused by insecticide challenge. The finding that selection for insecticide resistance can increase P. falciparum infection intensities and growth rate reinforces the need to assess the overall impact on malaria transmission dynamics caused by selective pressures mosquitoes experience during repeated insecticide challenge.
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Affiliation(s)
- Kelsey L Adams
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Emily K Selland
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Bailey C Willett
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - John W Carew
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Charles Vidoudez
- Harvard Center for Mass Spectrometry, Cambridge, Massachusetts, United States of America
| | - Naresh Singh
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Flaminia Catteruccia
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
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5
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Niang A, Sawadogo SP, Millogo AA, Akpodiete NO, Dabiré RK, Tripet F, Diabaté A. Entomological baseline data collection and power analyses in preparation of a mosquito swarm-killing intervention in south-western Burkina Faso. Malar J 2021; 20:346. [PMID: 34425839 PMCID: PMC8381508 DOI: 10.1186/s12936-021-03877-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/10/2021] [Indexed: 11/18/2022] Open
Abstract
Background Insecticides are currently the main tools used to reduce the transmission of malaria; therefore, the development of resistance to insecticides in malaria vectors is of major concern for malaria control. The resistance level to pyrethroids is particularly high in the Western region of Burkina Faso and may affect the efficacy of insecticidal bed nets and indoor residual spraying. Adult mosquito swarming and other nocturnal behaviours exhibit spatial and temporal patterns that suggest potential vulnerability to targeted space spraying with effective insecticides. Indeed, targeted space-spraying against adult mosquito swarms has been used to crash mosquito populations and disrupt malaria transmission. Methods Prior to impact assessment of swarm killing, a baseline data collection was conducted from June to November 2016 in 10 villages divided into two areas in western Burkina Faso. The data considered both ecological and demographic characteristics to monitor the key entomological parameters. Results The mean number of swarms observed was 35 per village, ranging from 25 to 70 swarms according to the village. Female density in both areas varied significantly as a function of the village and the period of collection. The human biting rate was significantly affected by the period of collection and depended upon whether the collection was carried out indoors or outdoors. Averages of parity rate were high in both areas for all periods of collection, ranging from 60 to 90%. These values ranged from 80 to 100% for inseminated females. Sporozoite rates ranged between 1.6 and 7.2% depending upon the village. The molecular identification of resting and swarming mosquitoes showed the presence of the three major malaria vectors in Burkina Faso, but in different proportions for each village. Conclusions The distribution of the potential swarm markers and swarms in villages suggested that swarms are clustered across space, making intervention easier. Power simulations showed that the direct sampling of swarms provides the highest statistical power, thereby reducing the number of villages needed for a trial. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03877-x.
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Affiliation(s)
- Abdoulaye Niang
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.
| | - Simon P Sawadogo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Abdoul A Millogo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.,Institut des Sciences des Sociétés (INSS), Ouagadougou, Burkina Faso
| | - Nwamaka O Akpodiete
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Abdoulaye Diabaté
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
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6
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Sanou R, Maïga H, Bilgo EM, Sawadogo SP, Sow BBD, Ouema A, Bayili K, Belem AMG, Toé LP, Dabiré RK, Diabaté A. Assessment of novel Lehmann's funnel entry trap prototypes performance to control malaria mosquito populations. Malar J 2021; 20:2. [PMID: 33386073 PMCID: PMC7777431 DOI: 10.1186/s12936-020-03532-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 12/07/2020] [Indexed: 12/02/2022] Open
Abstract
Background There is a global consensus that new intervention tools are needed for the final steps toward malaria elimination/eradication. In a recent study in Burkina Faso, the Lehmann Funnel Entry Trap (LFET) has shown promising results in the reduction of mosquito densities, even in areas where insecticide resistance is as high as 80%. The LFET requires no chemicals and is self-operated. However, one of the issues with the original LFET is the size of the funnel, which often occupies too much space within users’ homes. Here, the performance of three new, smaller-sized LFET prototypes that combine a screening and killing effect on mosquitoes was assessed. Methods The study was carried out over three months during the rainy season in low and high malaria vector density sites, Soumousso and Vallée du Kou, respectively. The original LFET (or ‘Prototype 1’/‘P1’) was modified to produce three new prototypes, which were referred to as prototype 2 (‘the Medium’ or ‘P2’), prototype 3 (P3) and prototype 4 (P4). Each of the new prototypes was tested on eight days per month over the three-month period to assess their effectiveness in trapping and killing mosquitoes entering houses through the windows compared to the original LFET. Results Overall, 78,435 mosquitoes (mainly Anopheles gambiae sensu lato) were collected in the two study sites, both in the traps and in the houses. A total of 56,430 (72%) mosquitoes were collected from the traps. In Vallée du Kou, the original LFET caught a greater number of mosquitoes than the medium (prototype 2), whereas no difference was observed between the other new prototypes (3 and 4) and the medium. In Soumousso, both the original and medium LFETs collected significantly greater numbers of mosquitoes compared to prototypes 3 and 4. Conclusion This study has shown that the new LFET prototypes are effective in trapping mosquitoes in high mosquito density settings. A large-scale study with one of the prototypes will be needed to assess community acceptance of the traps and their ability to control malaria vectors.
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Affiliation(s)
- Roger Sanou
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso. .,Université Nazi BONI de Bobo-Dioulasso, PO 1091, Bobo-Dioulasso, Burkina Faso.
| | - Hamidou Maïga
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Etienne M Bilgo
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Simon P Sawadogo
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Bazoumana B D Sow
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso.,Université Nazi BONI de Bobo-Dioulasso, PO 1091, Bobo-Dioulasso, Burkina Faso
| | - Adama Ouema
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso.,Université Nazi BONI de Bobo-Dioulasso, PO 1091, Bobo-Dioulasso, Burkina Faso
| | - Koama Bayili
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | | | - Léa Paré Toé
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Roch K Dabiré
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Abdoulaye Diabaté
- Institut de Recherche en Sciences de La Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso.
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Perugini E, Guelbeogo WM, Calzetta M, Manzi S, Virgillito C, Caputo B, Pichler V, Ranson H, Sagnon N, Della Torre A, Pombi M. Behavioural plasticity of Anopheles coluzzii and Anopheles arabiensis undermines LLIN community protective effect in a Sudanese-savannah village in Burkina Faso. Parasit Vectors 2020; 13:277. [PMID: 32487147 PMCID: PMC7268364 DOI: 10.1186/s13071-020-04142-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/21/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Despite the overall major impact of long-lasting insecticide treated nets (LLINs) in eliciting individual and collective protection to malaria infections, some sub-Saharan countries, including Burkina Faso, still carry a disproportionately high share of the global malaria burden. This study aims to analyse the possible entomological bases of LLIN limited impact, focusing on a LLIN-protected village in the Plateau Central region of Burkina Faso. METHODS Human landing catches (HLCs) were carried out in 2015 for 12 nights both indoors and outdoors at different time windows during the highest biting activity phase for Anopheles gambiae (s.l.). Collected specimens were morphologically and molecularly identified and processed for Plasmodium detection and L1014F insecticide-resistance allele genotyping. RESULTS Almost 2000 unfed An. gambiae (s.l.) (54% Anopheles coluzzii and 44% Anopheles arabiensis) females landing on human volunteers were collected, corresponding to a median number of 23.5 females/person/hour. No significant differences were observed in median numbers of mosquitoes collected indoors and outdoors, nor between sporozoite rates in An. coluzzii (6.1%) and An. arabiensis (5.5%). The estimated median hourly entomological inoculation rate (EIR) on volunteers was 1.4 infective bites/person/hour. Results do not show evidence of the biting peak during night hours typical for An. gambiae (s.l.) in the absence of bednet protection. The frequency of the L1014F resistant allele (n = 285) was 66% in An. coluzzii and 38% in An. arabiensis. CONCLUSIONS The observed biting rate and sporozoite rates are in line with the literature data available for An. gambiae (s.l.) in the same geographical area before LLIN implementation and highlight high levels of malaria transmission in the study village. Homogeneous biting rate throughout the night and lack of preference for indoor-biting activity, suggest the capacity of both An. coluzzii and An. arabiensis to adjust their host-seeking behaviour to bite humans despite bednet protection, accounting for the maintenance of high rates of mosquito infectivity and malaria transmission. These results, despite being limited to a local situation in Burkina Faso, represent a paradigmatic example of how high densities and behavioural plasticity in the vector populations may contribute to explaining the limited impact of LLINs on malaria transmission in holo-endemic Sudanese savannah areas in West Africa.
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Affiliation(s)
- Eleonora Perugini
- Dipartimento di Sanità Pubblica e Malattie Infettive, Laboratory affiliated to Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Sapienza Università di Roma, Rome, 00185, Italy
| | - Wamdaogo Moussa Guelbeogo
- Centre National de Recherche et Formation sur le Paludisme (CNRFP), Ouagadougou 01, BP 2208, Burkina Faso
| | - Maria Calzetta
- Dipartimento di Sanità Pubblica e Malattie Infettive, Laboratory affiliated to Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Sapienza Università di Roma, Rome, 00185, Italy
| | - Sara Manzi
- Dipartimento di Sanità Pubblica e Malattie Infettive, Laboratory affiliated to Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Sapienza Università di Roma, Rome, 00185, Italy
| | - Chiara Virgillito
- Dipartimento di Sanità Pubblica e Malattie Infettive, Laboratory affiliated to Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Sapienza Università di Roma, Rome, 00185, Italy.,Dipartimento di Biodiversità ed Ecologia Molecolare, Centro Ricerca e Innovazione, Fondazione Edmund Mach, San Michele all'Adige, Trento, Italy
| | - Beniamino Caputo
- Dipartimento di Sanità Pubblica e Malattie Infettive, Laboratory affiliated to Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Sapienza Università di Roma, Rome, 00185, Italy
| | - Verena Pichler
- Dipartimento di Sanità Pubblica e Malattie Infettive, Laboratory affiliated to Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Sapienza Università di Roma, Rome, 00185, Italy
| | - Hilary Ranson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - N'Fale Sagnon
- Centre National de Recherche et Formation sur le Paludisme (CNRFP), Ouagadougou 01, BP 2208, Burkina Faso
| | - Alessandra Della Torre
- Dipartimento di Sanità Pubblica e Malattie Infettive, Laboratory affiliated to Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Sapienza Università di Roma, Rome, 00185, Italy.
| | - Marco Pombi
- Dipartimento di Sanità Pubblica e Malattie Infettive, Laboratory affiliated to Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Sapienza Università di Roma, Rome, 00185, Italy.
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