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1.
Methods Mol Biol ; 2802: 587-609, 2024.
Article in English | MEDLINE | ID: mdl-38819573

ABSTRACT

Comparative analysis of (meta)genomes necessitates aggregation, integration, and synthesis of well-annotated data using standards. The Genomic Standards Consortium (GSC) collaborates with the research community to develop and maintain the Minimum Information about any (x) Sequence (MIxS) reporting standard for genomic data. To facilitate the use of the GSC's MIxS reporting standard, we provide a description of the structure and terminology, how to navigate ontologies for required terms in MIxS, and demonstrate practical usage through a soil metagenome example.


Subject(s)
Genomics , Metagenome , Metagenomics , Metagenomics/methods , Metagenomics/standards , Genomics/methods , Genomics/standards , Metagenome/genetics , Databases, Genetic , Soil Microbiology
2.
Pharmaceutics ; 16(2)2024 Jan 30.
Article in English | MEDLINE | ID: mdl-38399255

ABSTRACT

Long-acting injectable cabotegravir is more effective than daily oral PrEP at preventing HIV transmission due to improved adherence, but requires bi-monthly large-volume intramuscular injections. Subcutaneous (SC) contraceptive implants can be formulated with antiretrovirals for extended-duration HIV PrEP. Islatravir (ISL) is a first-in-class, investigational antiretroviral with pharmacologic properties well-suited for implant delivery. We performed preclinical studies for the development of a reservoir-style, poly(ε-caprolactone) ISL-eluting implant by conducting a single-dose SC ISL dose-ranging pharmacokinetic (PK) study of 0.1, 0.3, and 1 mg/kg in adult Wistar rats. Non-compartmental analysis was conducted, and dose proportionality assessed for ISL plasma and intracellular islatravir-triphosphate (ISL-tp). Population PK models estimated ISL's unit impulse response to deconvolve ISL-implant in vivo absorption rate (mg/day) and cumulative mass (mg) from published rat plasma PK (n = 10). Drug release was interpreted using four kinetic models. Dose proportionality was affirmed for ISL and ISL-tp. A first-order, two-compartment model fitted the SC ISL bolus data. Mean (SD) absorption rate from 0 to 154 days was 0.072 ± 0.024 mg/day, and cumulative mass at 154 days was 8.67 ± 3.22 mg. ISL absorption was well-described by zero-order (r2 = 0.95) and Ritger-Peppas (r2 = 0.98). Our zero-order ISL-release poly(ε-caprolactone) implant is projected to achieve clinical PK above ISL-tp's PrEP efficacy threshold. Continued development for HIV PrEP applications is warranted.

3.
Nat Ecol Evol ; 8(3): 500-510, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38273123

ABSTRACT

The capacity of arthropod populations to adapt to long-term climatic warming is currently uncertain. Here we combine theory and extensive data to show that the rate of their thermal adaptation to climatic warming will be constrained in two fundamental ways. First, the rate of thermal adaptation of an arthropod population is predicted to be limited by changes in the temperatures at which the performance of four key life-history traits can peak, in a specific order of declining importance: juvenile development, adult fecundity, juvenile mortality and adult mortality. Second, directional thermal adaptation is constrained due to differences in the temperature of the peak performance of these four traits, with these differences expected to persist because of energetic allocation and life-history trade-offs. We compile a new global dataset of 61 diverse arthropod species which provides strong empirical evidence to support these predictions, demonstrating that contemporary populations have indeed evolved under these constraints. Our results provide a basis for using relatively feasible trait measurements to predict the adaptive capacity of diverse arthropod populations to geographic temperature gradients, as well as ongoing and future climatic warming.


Subject(s)
Arthropods , Life History Traits , Animals , Temperature , Acclimatization , Phenotype
4.
Glob Chang Biol ; 30(1): e17041, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38273521

ABSTRACT

Most models exploring the effects of climate change on mosquito-borne disease ignore thermal adaptation. However, if local adaptation leads to changes in mosquito thermal responses, "one size fits all" models could fail to capture current variation between populations and future adaptive responses to changes in temperature. Here, we assess phenotypic adaptation to temperature in Aedes aegypti, the primary vector of dengue, Zika, and chikungunya viruses. First, to explore whether there is any difference in existing thermal response of mosquitoes between populations, we used a thermal knockdown assay to examine five populations of Ae. aegypti collected from climatically diverse locations in Mexico, together with a long-standing laboratory strain. We identified significant phenotypic variation in thermal tolerance between populations. Next, to explore whether such variation can be generated by differences in temperature, we conducted an experimental passage study by establishing six replicate lines from a single field-derived population of Ae. aegypti from Mexico, maintaining half at 27°C and the other half at 31°C. After 10 generations, we found a significant difference in mosquito performance, with the lines maintained under elevated temperatures showing greater thermal tolerance. Moreover, these differences in thermal tolerance translated to shifts in the thermal performance curves for multiple life-history traits, leading to differences in overall fitness. Together, these novel findings provide compelling evidence that Ae. aegypti populations can and do differ in thermal response, suggesting that simplified thermal performance models might be insufficient for predicting the effects of climate on vector-borne disease transmission.


Subject(s)
Aedes , Zika Virus Infection , Zika Virus , Animals , Mosquito Vectors/physiology , Aedes/physiology , Temperature
5.
Pharmaceutics ; 15(12)2023 11 26.
Article in English | MEDLINE | ID: mdl-38140017

ABSTRACT

The prevention of HIV and unintended pregnancies is a public health priority. Multi-purpose prevention technologies capable of long-acting HIV and pregnancy prevention are desirable for women. Here, we utilized a preclinical macaque model to evaluate the pharmacokinetics of biodegradable ε-polycaprolactone implants delivering the antiretroviral islatravir (ISL) and the contraceptive etonogestrel (ENG). Three implants were tested: ISL-62 mg, ISL-98 mg, and ENG-33 mg. Animals received one or two ISL-eluting implants, with doses of 42, 66, or 108 µg of ISL/day with or without an additional ENG-33 mg implant (31 µg/day). Drug release increased linearly with dose with median [range] plasma ISL levels of 1.3 [1.0-2.5], 1.9 [1.2-6.3] and 2.8 [2.3-11.6], respectively. The ISL-62 and 98 mg implants demonstrated stable drug release over three months with ISL-triphosphate (ISL-TP) concentr54ations in PBMCs above levels predicted to be efficacious for PrEP. Similarly, ENG implants demonstrated sustained drug release with median [range] plasma ENG levels of 495 [229-1110] pg/mL, which suppressed progesterone within two weeks and showed no evidence of altering ISL pharmacokinetics. Two of the six ISL-98 mg implants broke during the study and induced implant-site reactions, whereas no reactions were observed with intact implants. We show that ISL and ENG biodegradable implants are safe and yield sufficient drug levels to achieve prevention targets. The evaluation of optimized implants with increased mechanical robustness is underway for improved durability and vaginal efficacy in a SHIV challenge model.

6.
J Hand Ther ; 2023 Oct 03.
Article in English | MEDLINE | ID: mdl-37798187
7.
Microbiome ; 11(1): 192, 2023 08 26.
Article in English | MEDLINE | ID: mdl-37626434

ABSTRACT

As microbiome research has progressed, it has become clear that most, if not all, eukaryotic organisms are hosts to microbiomes composed of prokaryotes, other eukaryotes, and viruses. Fungi have only recently been considered holobionts with their own microbiomes, as filamentous fungi have been found to harbor bacteria (including cyanobacteria), mycoviruses, other fungi, and whole algal cells within their hyphae. Constituents of this complex endohyphal microbiome have been interrogated using multi-omic approaches. However, a lack of tools, techniques, and standardization for integrative multi-omics for small-scale microbiomes (e.g., intracellular microbiomes) has limited progress towards investigating and understanding the total diversity of the endohyphal microbiome and its functional impacts on fungal hosts. Understanding microbiome impacts on fungal hosts will advance explorations of how "microbiomes within microbiomes" affect broader microbial community dynamics and ecological functions. Progress to date as well as ongoing challenges of performing integrative multi-omics on the endohyphal microbiome is discussed herein. Addressing the challenges associated with the sample extraction, sample preparation, multi-omic data generation, and multi-omic data analysis and integration will help advance current knowledge of the endohyphal microbiome and provide a road map for shrinking microbiome investigations to smaller scales. Video Abstract.


Subject(s)
Microbiota , Multiomics , Data Analysis , Eukaryota , Microbiota/genetics , Prokaryotic Cells
8.
PeerJ ; 11: e15556, 2023.
Article in English | MEDLINE | ID: mdl-37465150

ABSTRACT

Skin microbial communities are an essential part of host health and can play a role in mitigating disease. Host and environmental factors can shape and alter these microbial communities and, therefore, we need to understand to what extent these factors influence microbial communities and how this can impact disease dynamics. Microbial communities have been studied in amphibian systems due to skin microbial communities providing some resistance to the amphibian chytrid fungus, Batrachochytrium dendrobatidis. However, we are only starting to understand how host and environmental factors shape these communities for amphibians. In this study, we examined whether amphibian skin bacterial communities differ among host species, host infection status, host developmental stage, and host habitat. We collected skin swabs from tadpoles and adults of three Ranid frog species (Lithobates spp.) at the Mianus River Gorge Preserve in Bedford, New York, USA, and used 16S rRNA gene amplicon sequencing to determine bacterial community composition. Our analysis suggests amphibian skin bacterial communities change across host developmental stages, as has been documented previously. Additionally, we found that skin bacterial communities differed among Ranid species, with skin communities on the host species captured in streams or bogs differing from the communities of the species captured on land. Thus, habitat use of different species may drive differences in host-associated microbial communities for closely-related host species.


Subject(s)
Chytridiomycota , Microbiota , Animals , RNA, Ribosomal, 16S/genetics , Chytridiomycota/genetics , Anura/genetics , Ranidae/genetics , Microbiota/genetics , Bacteria/genetics
9.
New Phytol ; 239(6): 2277-2291, 2023 09.
Article in English | MEDLINE | ID: mdl-37403524

ABSTRACT

Jasmonate (JA) re-programs metabolism to confer resistance to diverse environmental threats. Jasmonate stimulates the degradation of JASMONATE ZIM-DOMAIN (JAZ) proteins that repress the activity of MYC transcription factors. In Arabidopsis thaliana, MYC and JAZ are encoded by 4 and 13 genes, respectively. The extent to which expansion of the MYC and JAZ families has contributed to functional diversification of JA responses is not well understood. Here, we investigated the role of MYC and JAZ paralogs in controlling the production of defense compounds derived from aromatic amino acids (AAAs). Analysis of loss-of-function and dominant myc mutations identified MYC3 and MYC4 as the major regulators of JA-induced tryptophan metabolism. We developed a JAZ family-based, forward genetics approach to screen randomized jaz polymutants for allelic combinations that enhance tryptophan biosynthetic capacity. We found that mutants defective in all members (JAZ1/2/5/6) of JAZ group I over-accumulate AAA-derived defense compounds, constitutively express marker genes for the JA-ethylene branch of immunity and are more resistant to necrotrophic pathogens but not insect herbivores. In defining JAZ and MYC paralogs that regulate the production of amino-acid-derived defense compounds, our results provide insight into the specificity of JA signaling in immunity.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis Proteins/metabolism , Proto-Oncogene Proteins c-myc/genetics , Proto-Oncogene Proteins c-myc/metabolism , Repressor Proteins/metabolism , Tryptophan/metabolism , Signal Transduction , Arabidopsis/metabolism , Cyclopentanes/metabolism , Oxylipins/metabolism , Gene Expression Regulation, Plant
10.
Ecol Lett ; 26(7): 1029-1049, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37349261

ABSTRACT

Vector-borne diseases cause significant financial and human loss, with billions of dollars spent on control. Arthropod vectors experience a complex suite of environmental factors that affect fitness, population growth and species interactions across multiple spatial and temporal scales. Temperature and water availability are two of the most important abiotic variables influencing their distributions and abundances. While extensive research on temperature exists, the influence of humidity on vector and pathogen parameters affecting disease dynamics are less understood. Humidity is often underemphasized, and when considered, is often treated as independent of temperature even though desiccation likely contributes to declines in trait performance at warmer temperatures. This Perspectives explores how humidity shapes the thermal performance of mosquito-borne pathogen transmission. We summarize what is known about its effects and propose a conceptual model for how temperature and humidity interact to shape the range of temperatures across which mosquitoes persist and achieve high transmission potential. We discuss how failing to account for these interactions hinders efforts to forecast transmission dynamics and respond to epidemics of mosquito-borne infections. We outline future research areas that will ground the effects of humidity on the thermal biology of pathogen transmission in a theoretical and empirical framework to improve spatial and temporal prediction of vector-borne pathogen transmission.


Subject(s)
Culicidae , Vector Borne Diseases , Humans , Animals , Humidity , Mosquito Vectors , Temperature , Biology
11.
PLoS One ; 18(5): e0285711, 2023.
Article in English | MEDLINE | ID: mdl-37195918

ABSTRACT

BACKGROUND: Given the high rates of both HIV and unintended pregnancies in sub-Saharan Africa, the SCHIELD program aims to develop a multipurpose technology implant for HIV and pregnancy prevention. An end-user evaluation was undertaken with young women and health care providers to assess preferences for modifiable implant attributes to improve future adoption and rollout. METHODS: Focus group discussions were conducted with potential women end users, and health care providers experienced in implant insertion or removal participated in in-depth interviews. All participants were recruited from Harare, Zimbabwe, or Soshanguve, South Africa. The purposively stratified sampled women were either implant experienced or implant naïve and were categorized into three groups: nulliparous, postpartum, or engaged in transactional sex. Topics covered included duration (six months to three years), biodegradability, removability, and independent rod retrievability (per indication). Data were analyzed using Dedoose software and summarized into emerging themes. RESULTS: Participants identified three key areas that could facilitate rollout, uptake, and adherence of an implant for HIV and pregnancy prevention. First, discreetness was the most salient topic and was associated with implant characteristics such as anatomical location, flexibility, and biodegradability. Second, the ability to independently retrieve the HIV or pregnancy prevention component was preferred, as life circumstances may change and was favored by all participants, except for young women in Soshanguve. Third, there is a need for proper counseling, sensitization, provider training, and health campaigns to facilitate rollout of a 2-in-1 implant. CONCLUSIONS: A 2-in-1 implant was seen as highly desirable by most young women and health care providers. Participants discussed potential concerns and barriers to uptake of a biodegradable implant with dual HIV prevention and contraceptive properties, identifying key implant attributes that product developers can modify while still in preclinical stages.


Subject(s)
HIV Infections , Pregnancy, Unplanned , Pregnancy , Humans , Female , South Africa , Zimbabwe , Prospective Studies , HIV Infections/drug therapy , Health Personnel
12.
Malar J ; 22(1): 104, 2023 Mar 21.
Article in English | MEDLINE | ID: mdl-36945014

ABSTRACT

BACKGROUND: Anopheles stephensi is a malaria-transmitting mosquito that has recently expanded from its primary range in Asia and the Middle East, to locations in Africa. This species is a competent vector of both Plasmodium falciparum and Plasmodium vivax malaria. Perhaps most alarming, the characteristics of An. stephensi, such as container breeding and anthropophily, make it particularly adept at exploiting built environments in areas with no prior history of malaria risk. METHODS: In this paper, global maps of thermal transmission suitability and people at risk (PAR) for malaria transmission by An. stephensi were created, under current and future climate. Temperature-dependent transmission suitability thresholds derived from recently published species-specific thermal curves were used to threshold gridded, monthly mean temperatures under current and future climatic conditions. These temperature driven transmission models were coupled with gridded population data for 2020 and 2050, under climate-matched scenarios for future outcomes, to compare with baseline predictions for 2020 populations. RESULTS: Using the Global Burden of Disease regions approach revealed that heterogenous regional increases and decreases in risk did not mask the overall pattern of massive increases of PAR for malaria transmission suitability with An. stephensi presence. General patterns of poleward expansion for thermal suitability were seen for both P. falciparum and P. vivax transmission potential. CONCLUSIONS: Understanding the potential suitability for An. stephensi transmission in a changing climate provides a key tool for planning, given an ongoing invasion and expansion of the vector. Anticipating the potential impact of onward expansion to transmission suitable areas, and the size of population at risk under future climate scenarios, and where they occur, can serve as a large-scale call for attention, planning, and monitoring.


Subject(s)
Anopheles , Malaria, Falciparum , Malaria, Vivax , Malaria , Humans , Animals , Malaria/epidemiology , Malaria, Falciparum/epidemiology , Plasmodium falciparum , Africa/epidemiology , Mosquito Vectors
13.
BMC Womens Health ; 23(1): 58, 2023 02 10.
Article in English | MEDLINE | ID: mdl-36765358

ABSTRACT

BACKGROUND: Input from end-users during preclinical phases can support market fit for new HIV prevention technologies. With several long-acting pre-exposure prophylaxis (PrEP) implants in development, we aimed to understand young women's preferences for PrEP implants to inform optimal design. METHODS: We developed a discrete choice experiment and surveyed 800 young women in Harare, Zimbabwe and Tshwane, South Africa between September-November 2020. Women aged 18-30 years who were nulliparous, postpartum, or exchanged sex for money, goods or shelter in prior year were eligible; quotas were set for each subgroup. The DCE asked participants to choose between two hypothetical implants for HIV prevention in a series of nine questions. Implants were described by: size, number of rods and insertion sites, duration (6-months, 1-year, 2-years), flexibility, and biodegradability. Random-parameters logit models estimated preference weights. RESULTS: Median age was 24 years (interquartile range 21-27). By design, 36% had used contraceptive implants. Duration of protection was most important feature, with strong preference for a 2-year over 6-month implant. In Zimbabwe, the number of rods/insertion sites was second most important and half as important as duration. Nonetheless, to achieve an implant lasting 2-years, 74% were estimated to accept two rods, one in each arm. In South Africa, preference was for longer, flexible implants that required removal, although each of these attributes were one-third as important as duration. On average, biodegradability and size did not influence Zimbabwean women's choices. Contraceptive implant experience and parity did not influence relative importance of attributes. CONCLUSIONS: While duration of protection was a prominent attribute shaping women's choices for PrEP implants, other characteristics related to discreetness were relevant. Optimizing for longest dosing while also ensuring minimal detection of implant placement seemed most attractive to potential users.


Subject(s)
HIV Infections , Pregnancy , Humans , Female , Young Adult , Adult , HIV Infections/prevention & control , Zimbabwe , South Africa , Surveys and Questionnaires , Contraceptive Agents
14.
BMJ Open ; 13(1): e071274, 2023 01 25.
Article in English | MEDLINE | ID: mdl-36697053

ABSTRACT

INTRODUCTION: Current clinical applications of virtual reality (VR) provide patients with transient pain relief during acutely painful events by redirecting attention. Biofeedback (BF) is a mind-body therapy that effectively produces sustained pain reduction, but there are obstacles to its routine use. Combined, BF-based VR (VR-BF) may increase accessibility while enhancing the benefits of BF. VR-BF has yet to be employed in perioperative care, and as such, no defined treatment protocol for VR-BF exists. The primary aim of this study is to assess the feasibility of the perioperative use of VR-BF in children and adolescents. The secondary aims are to assess the acceptability of VR-BF and to collect pilot efficacy data. METHODS AND ANALYSIS: This is a single-centre, randomised controlled pilot clinical trial. A total of 70 patients (12-18 years) scheduled for surgery anticipated to cause moderate to severe pain with ≥1 night of hospital admission will be randomised to one of two study arms (VR-BF or control). Participants randomised to VR-BF (n=35) will use the ForeVR VR platform to engage their breathing in gamified VR applications. Participants randomised to control (n=35) will interact with a pain reflection app, Manage My Pain. The primary outcome is feasibility of VR-BF use in adolescents undergoing surgery as assessed through recruitment, enrolment, retention and adherence to the protocol. Secondary outcomes are acceptability of VR-BF and pilot efficacy measures, including pain, anxiety and opioid consumption. ETHICS AND DISSEMINATION: The protocol was approved by the Nationwide Children's Hospital Institutional Review Board (IRB #STUDY00002080). Patient recruitment begins in March 2023. Written informed consent is obtained for all participants. All information acquired will be disseminated via scientific meetings and published in peer-reviewed journals. Data will be available per request and results will be posted on ClinicalTrials.gov. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT04943874).


Subject(s)
Pain , Virtual Reality , Humans , Child , Adolescent , Feasibility Studies , Pilot Projects , Anxiety/prevention & control , Biofeedback, Psychology , Randomized Controlled Trials as Topic
16.
Pharmaceuticals (Basel) ; 15(10)2022 Oct 03.
Article in English | MEDLINE | ID: mdl-36297338

ABSTRACT

Controlled drug delivery systems can provide sustained release profiles, favorable pharmacokinetics, and improved patient adherence. Here, a reservoir-style implant comprising a biodegradable polymer, poly(ε-caprolactone) (PCL), was developed to deliver drugs subcutaneously. This work addresses a key challenge when designing these implantable drug delivery systems, namely the accurate prediction of drug release profiles when using different formulations or form factors of the implant. The ability to model and predict the release behavior of drugs from an implant based on their physicochemical properties enables rational design and optimization without extensive and laborious in vitro testing. By leveraging experimental observations, we propose a mathematical model that predicts the empirical parameters describing the drug diffusion and partitioning processes based on the physicochemical properties of the drug. We demonstrate that the model enables an adequate fit predicting empirical parameters close to experimental values for various drugs. The model was further used to predict the release performance of new drug formulations from the implant, which aligned with experimental results for implants exhibiting zero-order release kinetics. Thus, the proposed empirical models provide useful tools to inform the implant design to achieve a target release profile.

17.
AIDS Patient Care STDS ; 36(10): 389-395, 2022 10.
Article in English | MEDLINE | ID: mdl-36286579

ABSTRACT

In South Africa, less than half of children receiving antiretroviral therapy are virally suppressed. Adherence challenges include poor palatability of drugs and high pill burden. Subcutaneous implants offer a long-acting alternative to daily oral dosing regimens, which may improve outcomes in children living with HIV (CLWH). Qualitative in-depth interviews were conducted with 24 health care providers (HCPs) in Johannesburg, South Africa. Interviews were audio-recorded and transcribed. Data were coded and analyzed using NVivo 12 software and a Grounded Theory approach. Most HCPs welcomed an implant option for CLWH. Perceived benefits included fewer clinic visits, improved adherence, and "normalization" of the lives of CLWH. Concerns included painful insertion and removal, the potential for stigmatization, and caregivers' likely rejection of biodegradable implants. A single, small, non-transparent rod with some flexibility was preferred by most participants. HCP training and early outreach to mitigate potential misinformation about implants and caregivers' fears about biodegradable implants were emphasized. Further engagement with caregivers of CLWH is required and ongoing.


Subject(s)
HIV Infections , Child , Humans , Child, Preschool , HIV Infections/drug therapy , South Africa , Health Personnel , Caregivers , Attitude of Health Personnel , Qualitative Research
18.
Nanomaterials (Basel) ; 12(15)2022 Aug 05.
Article in English | MEDLINE | ID: mdl-35957130

ABSTRACT

Microplastics (MPs) and nanoplastics (NPs) exist in certain environments, beverages, and food products. However, the ultimate risk and consequences of MPs and NPs on human health remain largely unknown. Studies involving the biological effects of small-scale plastics have predominantly used commercially available polystyrene beads, which cannot represent the breadth of globally dominant plastics. Nylon is a commodity plastic that is used across various industry sectors with substantial global production. Here, a series of well-characterized nylon-11 and nylon-6 NPs were successfully fabricated with size distributions of approximately 100 nm and 500 nm, respectively. The facile fabrication steps enabled the incorporation of fluorescent tracers in these NPs to aid the intracellular tracking of particles. RAW 264.7 macrophages were exposed to nylon NPs in a dose-dependent manner and cytotoxic concentrations and cellular uptake were determined. These well-characterized nylon NPs support future steps to assess how the composition and physicochemical properties may affect complex biological systems and ultimately human health.

20.
Ecology ; 103(8): e3685, 2022 08.
Article in English | MEDLINE | ID: mdl-35315521

ABSTRACT

Extrinsic environmental factors influence the spatiotemporal dynamics of many organisms, including insects that transmit the pathogens responsible for vector-borne diseases (VBDs). Temperature is an especially important constraint on the fitness of a wide variety of ectothermic insects. A mechanistic understanding of how temperature impacts traits of ectotherms, and thus the distribution of ectotherms and vector-borne infections, is key to predicting the consequences of climate change on transmission of VBDs like malaria. However, the response of transmission to temperature and other drivers is complex, as thermal traits of ectotherms are typically nonlinear, and they interact to determine transmission constraints. In this study, we assess and compare the effect of temperature on the transmission of two malaria parasites, Plasmodium falciparum and Plasmodium vivax, by two malaria vector species, Anopheles gambiae and Anopheles stephensi. We model the nonlinear responses of temperature dependent mosquito and parasite traits (mosquito development rate, bite rate, fecundity, proportion of eggs surviving to adulthood, vector competence, mortality rate, and parasite development rate) and incorporate these traits into a suitability metric based on a model for the basic reproductive number across temperatures. Our model predicts that the optimum temperature for transmission suitability is similar for the four mosquito-parasite combinations assessed in this study, but may differ at the thermal limits. More specifically, we found significant differences in the upper thermal limit between parasites spread by the same mosquito (A. stephensi) and between mosquitoes carrying P. falciparum. In contrast, at the lower thermal limit the significant differences were primarily between the mosquito species that both carried the same pathogen (e.g., A. stephensi and A. gambiae both with P. falciparum). Using prevalence data, we show that the transmission suitability metric ST$$ S(T) $$ calculated from our mechanistic model is consistent with observed P. falciparum prevalence in Africa and Asia but is equivocal for P. vivax prevalence in Asia, and inconsistent with P. vivax prevalence in Africa. We mapped risk to illustrate the number of months various areas in Africa and Asia predicted to be suitable for malaria transmission based on this suitability metric. This mapping provides spatially explicit predictions for suitability and transmission risk.


Subject(s)
Anopheles , Malaria, Falciparum , Malaria, Vivax , Temperature , Animals , Anopheles/parasitology , Anopheles/physiology , Malaria, Falciparum/epidemiology , Malaria, Falciparum/transmission , Malaria, Vivax/epidemiology , Malaria, Vivax/transmission , Mosquito Vectors
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