Biology subjects

Dinglasan, R. R.

Publications and source records attributed to Dinglasan, R. R..

11 recordsLinked to original sources

bioRxiv2026

Microspatial partitioning of insect-specific viromes and dengue virus transmission risk by Aedes aegypti in Puerto Rico

Mosquito-borne arboviruses remain a major global health threat. Although insect-specific viruses (ISVs) may influence arbovirus transmission across geographic regions, their diversity within Aedes aegypti populations at microspatial scales remains poorly understood. We hypothesized that local environmental variation shapes the A. aegypti core virome, producing distinct ISV profiles in rural and urban populations in Puerto Rico. Metatranscriptomic RNA sequencing of F0 mosquitoes identified thirteen ISVs with habitat-specific virome composition. Partitiviridae was the dominant viral family, while Humaita-Tubiacanga virus (HTV) and Phasi Charoen-like phasivirus (PCLV) exhibited the highest abundance, persistence, and prevalence in urban laboratory colonies. Urban A. aegypti also showed significantly higher dengue virus-1 (DENV-1) infection rates than rural populations, although saliva positivity remained low and did not differ significantly between the two groups. These findings indicate that microspatial ecological variation shapes the A. aegypti virome, but the association of HTV/PCLV with DENV-1 transmission risk is likely multifactorial and nuanced.

microbiology↗

bioRxiv2026

Metabolomic changes underpinning permethrin resistance in the Anopheles gambiae malaria vector from Cameroon

Insecticide resistance reduces the effectiveness of current malaria vector control interventions. To understand the mechanisms underlying permethrin resistance in field-derived Anopheles gambiae vectors collected from Cameroon, we used Ultra-High Performance Liquid Chromatography coupled with High-Resolution Tandem Mass Spectrometry (UHPLC-HRMS/MS) to comprehensively analyze metabolic changes in resistant and susceptible samples to gain insight into mechanisms driven permethrin resistance. Resistant mosquitoes exhibited upregulated levels of inosine, nicotinic acid, dipeptides, amino acids, fumarate, uracil, and aldopentose. These data suggest that altered metabolic-based detoxification, as well as target site and metabolic shifts, and enhanced energy production contribute to permethrin resistance. Conversely, susceptible mosquitoes showed increased levels of N-acetyl-aspartic acid, xanthurenic acid, 2-hydroxyglutarate, 3-hydroxykynurenine, propanoylcarnitine, and L-pipecolic acid. These metabolites are associated with neurotoxicity, energy disruption, as well as tryptophan and lysine catabolism. These findings elucidate the metabolic pathways of permethrin-resistance and underscore the mechanisms that could lead to the emergence of pyrethroid cross-resistance.

systems biology↗

bioRxiv2025

Malaria entomological surveillance in Kinshasa Province: A longitudinal study

BackgroundMalaria remains a major public health challenge in the Democratic Republic of Congo. To address the lack of contemporary entomological data, particularly in Kinshasa Province, this four-year study characterized key entomological parameters, including mosquito species composition, abundance, biting behavior, and insecticide resistance. MethodsWe conducted a prospective observational cohort study (2018-2022) in three health areas representing rural, peri-urban, and urban settings in Kinshasa Province. Adult Anopheles mosquitoes were sampled using CDC miniature light traps and pyrethrum spray catches. Insecticide susceptibility of adult females was assessed using WHO tube tests, and a generalized estimating equations model evaluated the effects of year, season, site, sampling location, and collection time on mosquito abundance. ResultsA total of 1,449 Anopheles mosquitoes were collected: 50% in the rural health area of Bu, 49% in peri-urban Kimpoko, and 1% in urban La Voix du Peuple. The species captured were An. gambiae s.l. (85%), An. paludis (11%), and An. funestus (4%). An. gambiae s.l. was significantly more abundant indoors and after 10 PM. The overall entomological inoculation rate (EIR) was 4.6 infective bites per person per year, with An. gambiae s.l. contributing the highest rate. An. paludis showed a localized transmission peak in Impuru during the rainy season (EIR = 8.87). Resistance to DDT and pyrethroids was widespread, with an estimated 0.94 frequency of the kdr L1014F mutation. Bendiocarb and pirimiphos-methyl remained effective. ConclusionsThis study confirms that An. gambiae s.l. remains the predominant malaria vector and plays a central role in transmission in Kinshasa. However, an emerging role of An. paludis in rural settings was observed. These findings underscore the need for vector control strategies tailored to diverse ecological settings. Continued entomological surveillance will be essential to track biting behavior and resistance patterns and ensure that interventions remain effective over time. Author summaryMalaria remains a major health problem in the Democratic Republic of the Congo, but very little recent information is available about the mosquitoes that spread the disease, especially in Kinshasa Province. To help fill this gap, we spent four years studying mosquitoes in rural, peri-urban, and urban communities. We focused on how many mosquitoes were present, which species they were, when and where they bite, and whether they were resistant to the insecticides commonly used in malaria control. We found that most mosquitoes belonged to Anopheles gambiae, the main malaria-transmitting species in Africa. These mosquitoes mostly bit indoors and late at night, when bed nets can offer good protection. However, we also observed mosquitoes biting earlier in the evening and outside, which may reduce the impact of bed nets. Another species, Anopheles paludis, played an important role in malaria transmission in some rural areas, showing that different environments can shape which mosquitoes spread the disease. We also found that many mosquitoes were resistant to widely used insecticides, although some alternative insecticides were still effective. Our findings show why it is important to monitor mosquito behavior and insecticide resistance regularly and to adapt malaria prevention strategies to local conditions.

ecology↗

bioRxiv2021

Intrinsic variation in the vertically transmitted insect-specific core virome of Aedes aegypti

Since 2009, local outbreaks of dengue (serotypes 1-3) mediated by Aedes aegypti mosquitoes have occurred in the United States, particularly in Florida (FL). In 2016 and 2017, dengue virus serotype 4 was found alongside several insect-specific viruses (ISVs) in pools of A. aegypti from sites in Manatee County, FL, in the absence of an index case. Although ISVs have been characterized in A. aegypti globally, the constitution of a core virome in natural populations remains unclear. Using mosquitoes sampled from the same area in 2018, we compared baseline ovary viromes of field (G0) and lab (Orlando) A. aegypti via metagenomic RNA sequencing. Across all samples, virome composition varied by sample type (field- or colony-derived). Four ISVs comprised >97% of virus sequences: a novel partiti-like virus (Partitiviridae), a previously described toti-like virus (Totiviridae), unclassified Riboviria, and four previously described orthomyxo-like viruses (Orthormyxoviridae). Whole or partial genomes for the toti-like virus, partiti-like virus, and one orthomyxo-like virus were assembled and analyzed phylogenetically. Multigenerational maintenance of these ISVs was confirmed orthogonally by RT-PCR in G0 and G7 mosquitoes, indicating vertical transmission as the mechanism for ISV sustentation. This study provides fundamental information regarding ISV ecology, persistence, and variation in A. aegypti in nature.

microbiology↗

bioRxiv2021

Ecology and transmission of a dengue virus serotype 4 identified in wild Aedes aegypti in Florida

1Dengue virus is the most prevalent mosquito-borne virus, causing approximately 390 million infections and 25,000 deaths per year. Aedes aegypti, the primary mosquito vector of dengue virus, is well established throughout the state of Florida, USA. Autochthonous transmission of dengue virus to humans in Florida has been increasing since 2009, alongside consistent importation of dengue cases. However, most cases of first infection with dengue are asymptomatic and the virus can be maintained in mosquito populations, complicating surveillance and leading to an underestimation of disease risk. Metagenomic sequencing of Aedes aegypti mosquitoes in Manatee County, Florida revealed the presence of dengue virus serotype 4 (DENV-4) genomes in mosquitoes from multiple trapping sites over 2 years, in the absence of a human DENV-4 index case and even though a locally acquired case of DENV-4 has never been reported in Florida. This finding suggested that: i) DENV-4 may circulate amongst humans undetected, ii) the virus was being maintained in the mosquito population, or iii) the detected complete genome sequence may not represent a viable virus. This study demonstrates that an infectious clone generated from the Manatee County DENV-4 (DENV-4M) sequence is capable of infecting mammalian and insect tissue culture systems, as well as adult female Aedes aegypti mosquitoes when fed in a blood meal. However, the virus is subject to a dose dependent infection barrier in mosquitoes, and has a kinetic delay compared to a phylogenetically related wild-type (WT) control virus from a symptomatic child, DENV-4H (strain Homo sapiens/Haiti-0075/2015, GenBank accession MK514144.1). DENV-4M disseminates from the midgut to the ovary and saliva at 14 days post-infection. Viral RNA was also detectable in the adult female offspring of DENV-4M infected mosquitoes. These results demonstrate that the virus is capable of infecting vector mosquitoes, is transmissible by bite, and is vertically transmitted, indicating a mechanism for maintenance in the environment without human-mosquito transmission. These findings suggest undetected human-mosquito transmission and/or long-term maintenance of the virus in the mosquito population is occurring in Florida, and underscore the importance of proactive surveillance for viruses in mosquitoes. Graphical AbstractIn order to better assess the public health risk posed by a detection of DENV-4 RNA in Manatee County, FL Aedes aegypti, we produced an infectious clone using the sequence from the wild-caught mosquitoes and characterized it via laboratory infections of mosquitoes and mosquito tissues.

microbiology↗

bioRxiv2021

Niclosamide reverses SARS-CoV-2 control of lipophagy

The global effort to combat COVID-19 rapidly produced a shortlist of approved drugs with anti-viral activities for clinical repurposing. However, the jump to clinical testing was lethal in some cases as a full understanding of the mechanism of antiviral activity as opposed to pleiotropic activity/toxicity for these drugs was lacking. Through parallel lipidomic and transcriptomic analyses we observed massive reorganization of lipid profiles of infected Vero E6 cells, especially plasmalogens that correlated with increased levels of virus replication. Niclosamide (NIC), a poorly soluble anti-helminth drug identified for repurposed treatment of COVID-19, reduced the total lipid profile that would otherwise amplify during virus infection. NIC treatment reduced the abundance of plasmalogens, diacylglycerides, and ceramides, which are required for virus production. Future screens of approved drugs may identify more druggable compounds than NIC that can safely but effectively counter SARS-CoV-2 subversion of lipid metabolism thereby reducing virus replication. However, these data support the consideration of niclosamide as a potential COVID-19 therapeutic given its modulation of lipophagy leading to the reduction of virus egress and the subsequent regulation of key lipid mediators of pathological inflammation.

microbiology↗

bioRxiv2021

Transmission potential of Floridian Aedes aegypti mosquitoes for dengue virus serotype 4: Implications for estimating local dengue risk

Dengue virus serotype 4 (DENV-4) circulated in Aedes aegypti in 2016 and 2017 in Florida in the absence of human index cases, compelling a full assessment of local mosquito vector competence and DENV-4 risk. To better understand DENV-4 transmission risk in Florida, we used an expanded suite of tests to measure and compare the vector competence of both an established colony of Ae. aegypti (Orlando strain [ORL]) and a field-derived colony from Collier County, Florida in 2018 (COL) for a Haitian DENV-4 human field isolate and a DENV-4 laboratory strain (Philippines H241). We immediately noted that ORL saliva-positivity was higher for the field versus laboratory DENV-4 strains. In a subsequent comparison with the recent COL mosquito colony we also observed significantly higher midgut susceptibility of COL and ORL for the Haitian DENV-4 field strain, and significantly higher saliva-positivity rate for COL, although overall saliva virus titers were similar between the two. These data point to a potential midgut infection barrier for the DENV-4 laboratory strain for both mosquito colonies and that the marked difference in transmission potential estimates hinge on virus-vector combinations. Our study highlights the importance of leveraging an expanded suite of testing methods with emphasis on utilizing local mosquito populations and field relevant dengue serotypes and strains to accurately estimate transmission risk in a given setting. ImportanceDENV-4 was found circulating in Florida (FL) Ae. aegypti mosquitoes in the absence of human index cases in the state (2016-2017). How DENV-4 was maintained locally is unclear, presenting a major gap in our understanding of DENV-4 public health risk. We determined the baseline arbovirus transmission potential of laboratory and field colonies of Ae. aegypti for both laboratory and field isolates of DENV-4. We observed high transmission potential of field populations of Ae. aegypti and evidence of higher vertical transmission of the DENV-4 field isolate, providing clues to the possible mechanism of undetected DENV-4 maintenance in the state. Our findings also move the field forward in the development of best practices for evaluating arbovirus vector competence, with evidence that transmission potential estimates vary depending on the mosquito-virus combinations. These data emphasize the poor suitability of lab-established virus strains and the high relevance of field-derived mosquito populations in estimating transmission risk.

microbiology↗

bioRxiv2020

Immunofocusing humoral immunity potentiates the functional efficacy of the AnAPN1 malaria transmission-blocking vaccine antigen

Malaria transmission-blocking vaccines (TBVs) are a critical tool for disease elimination. TBVs prevent completion of the developmental lifecycle of malarial parasites within the mosquito vector, effectively blocking subsequent infections. The mosquito midgut protein Anopheline alanyl aminopeptidase N (AnAPN1) is the leading, mosquito-based TBV antigen and structure-function studies have identified two Class II epitopes that induce potent transmission-blocking (T-B) antibodies. Here, we functionally screened new immunogens and down-selected to the UF6b construct that has two glycine-linked copies of the T-B epitopes. We established a process for manufacturing UF6b and evaluated in outbred female CD1 mice the immunogenicity of the preclinical product with the human-safe adjuvant Glucopyranosyl Lipid Adjuvant in a liposomal formulation with saponin QS21 (GLA-LSQ). UF6b:GLA-LSQ was immunogenic and immunofocused the humoral response to one of the key T-B epitopes resulting in potent T-B activity and establishing UF6b as a prime TBV candidate to aid in malaria elimination and eradication efforts.

immunology↗

bioRxiv2020

Clustered Rapid Induction of Apoptosis Limits ZIKV and DENV-2 Proliferation in the Midguts of Aedes aegypti

Inter-host transmission of pathogenic arboviruses such as dengue virus (DENV) and Zika virus (ZIKV) requires systemic infection of the mosquito vector. Successful systemic infection requires initial viral entry and proliferation in the midgut cells of the mosquito followed by dissemination to secondary tissues and eventual entry into salivary glands1. Lack of arbovirus proliferation in midgut cells has been observed in several Aedes aegypti strains2, but the midgut antiviral responses underlying this phenomenon are not yet fully understood. We report here that there is a rapid induction of apoptosis (RIA) in the Aedes aegypti midgut epithelium within 2 hours of infection with DENV-2 or ZIKV in both in vivo blood-feeding and ex vivo midgut infection models. Inhibition of RIA led to increased virus proliferation in the midgut, implicating RIA as an innate immune mechanism mediating midgut infection in this mosquito vector.

microbiology↗

bioRxiv2020

Under-the-radar dengue virus infections in natural populations of Aedes aegypti mosquitoes

The incidence of locally acquired dengue infections increased during the last decade in the United States, compelling a sustained research effort on the dengue mosquito vector, Aedes aegypti, and its microbiome, which has been shown to influence virus transmission success. We examined the metavirome of four populations of Ae. aegypti mosquitoes collected in 2016-2017 from Manatee County, Florida. Unexpectedly, we discovered that dengue virus serotype 4 (DENV4) was circulating in these mosquito populations, representing the first documented case of such a phenomenon in the absence of a local DENV4 human case in this county over a two-year period. We confirmed that all of the mosquito populations carried the same DENV4 strain, assembled its full genome, validated infection orthogonally by reverse transcriptase PCR, traced the virus origin, estimated the time period of its introduction to the Caribbean region, as well as explored the viral genetic signatures and mosquito-specific virome associations that potentially mediated DENV4 persistence in mosquitoes. We discuss the significance of prolonged maintenance of these DENV4 infections in Ae. aegypti that occurred in the absence of a DENV4 human index case in Manatee County with respect to the inability of current surveillance paradigms to detect mosquito vector infections prior to a potential local outbreak. ImportanceSince 1999, dengue outbreaks in the continental United States (U.S.) involving local transmission have occurred episodically and only in Florida and Texas. In Florida, these episodes appear to be coincident with increased introductions of dengue virus into the region through human travel and migration from endemic countries. To date, the U.S. public health response to dengue outbreaks is largely reactive, and implementation of comprehensive arbovirus surveillance in advance of predictable transmission seasons, which would enable proactive preventative efforts, remains unsupported. The significance of our finding is that it is the first documented report of non-outbreak DENV4 transmission and maintenance within a local mosquito vector population in the continental U.S.in the absence of a human case during a two-year time period. Our data suggest that molecular surveillance of mosquito populations in high-risk, high tourism areas of the U.S., may allow for proactive, targeted vector control before potential arbovirus outbreaks.

ecology↗

bioRxiv2018

Modelling the distribution of Aedes aegypti and Aedes albopictus using climate, host density and interspecies competitive effects

Florida faces the challenge of repeated introduction and autochthonous transmission of arboviruses transmitted by Aedes aegypti and Aedes albopictus. Empirically-based predictive models of the spatial distribution of these species would aid surveillance and vector control efforts. To predict the occurrence and abundance of these species, we fit mixed-effects zero-inflated negative binomial regression to a mosquito surveillance dataset with records from more than 200,000 trap days, covering 73% of the land area and ranging from 2004 to 2018 in Florida. We found an asymmetrical competitive interaction between adult populations of Aedes aegypti and Aedes albopictus for the sampled sites. Wind speed was negatively associated with the occurrence and abundance of both vectors. Our model predictions show high accuracy (72.9% to 94.5%) in the validation tests leaving out a random 10% subset of sites and data from 2018, suggesting a potential for predicting the distribution of the two Aedes vectors.

ecology↗