Biology subjects

Pakparnich, P.

Publications and source records attributed to Pakparnich, P..

3 recordsLinked to original sources

bioRxiv2025

Natural salivary gland barrier curtails Zika virus transmission in Thai Aedes aegypti

BackgroundVector competence is a critical determinant of arbovirus transmission dynamics, yet most studies in Thailand have primarily examined Aedes aegypti susceptibility to infection and systemic viral dissemination rather than the mosquitos potential to transmit infectious virions. Given that transmission potential varies among mosquito populations, identifying population-specific transmission barriers is crucial for optimizing vector control strategies especially under budget and resource constrains. Methodology/Principal FindingsThis study assessed the Zika virus (ZIKV) transmission potential of three Ae. aegypti populations from Thailand: two field-derived populations from Chiang Mai (CSP) and Nakhon Sawan (NAK) and a long-established laboratory strain (DMSC). Following oral exposure to a locally circulating ZIKV strain, viral transmission potential was evaluated. CSP mosquitoes demonstrated the earliest and highest ZIKV prevalence in salivary glands at 7 days post-infectious blood meal (dpibm), with DMSC and NAK populations reaching comparable infection levels at later time points. Despite this, NAK mosquitoes exhibited a strong barrier, resulting in significantly lower transmission potential. Genetic crosses revealed that this phenotype is inherited as an autosomal dominant trait and is similarly effective against dengue virus serotype 2 (DENV2), underscoring the broad-spectrum potential of NAK Ae. aegypti for transmission suppression. Furthermore, male NAK mosquitoes exhibited superior mating competitiveness, reinforcing their viability as a tool for vector control by population replacement. Conclusions/SignificanceOur findings highlight significant variability in ZIKV vector competence among Thai Ae. aegypti populations, emphasizing the importance of direct transmission assessments in vector competence studies. The discovery of a naturally occurring, heritable salivary gland escape barrier presents an opportunity for vector control strategies through NAK-based population replacement approaches. With their strong mating capability and broad arbovirus-blocking ability, NAK mosquitoes provide a natural alternative to Wolbachia-based and genetically modified mosquito interventions. Author summaryAedes aegypti is the primary vector of arboviruses such as Zika virus (ZIKV) and dengue virus (DENV), but not all mosquitoes that become infected successfully transmit the virus. While most research in Thailand has focused on mosquito infection and virus dissemination, fewer studies have examined the ability of mosquitoes to transmit infectious virus through their saliva. We discovered a mosquito population from Nakhon Sawan (NAK) that exhibits a natural barrier to virus release from the salivary glands, leading to significant blocking of virus transmission in ZIKV-infected mosquitoes. This salivary gland escape barrier of NAK is a heritable autosomal dominant characteristic that also restricts DENV transmission. Given their high mating competitiveness, NAK mosquitoes present a promising candidate for population replacement strategies aimed at reducing arbovirus transmission. Our findings emphasize the importance of assessing transmission rates rather than relying solely on infection and dissemination rates. Furthermore, the discovery of a naturally occurring mosquito population with reduced transmission potential offers a practical and sustainable vector control approach. The implementation of NAK-based population replacement strategies could serve as an alternative to traditional control methods, such as insecticide application or genetically modified mosquito releases. Future research should focus on field trials to validate the efficacy of this approach in real-world settings and assess its long-term impact on virus transmission dynamics.

microbiology↗

bioRxiv2024

Comprehensive intra-host infection kinetics reveals high arbo-flavivirus transmission potential by neglected vector species, Aedes scutellaris

BackgroundDengue virus (DENV) and Zika virus (ZIKV) are primarily transmitted by Aedes mosquitoes. As most studies on vector competence have focused on Aedes aegypti and Aedes albopictus while neglecting other Aedes species, it is possible that the transmission risks might be underestimated. it is necessary to examine additional species that could potentially serve as competent vectors. This is particularly important considering the potential expansion of their geographical range due to climate change or species-specific vector reduction interventions. Methodology/Principal FindingsIn this study, we examined the infection kinetics and transmission potential of Aedes scutellaris from Thailand, comparing to Ae. aegypti and Ae. albopictus. Our findings demonstrated that Ae. scutellaris and Ae. albopictus had lower rates of midgut infection compared to Ae. aegypti due to smaller blood meal sizes during feeding. However, once the infection has established Ae. scutellaris exhibited efficient replication of ZIKV and DENV1-4 in the midguts, secondary organs, and salivary glands. Notably, Ae. scutellaris had a low salivary gland escape barrier, with comparable transmissibility as Ae. aegypti when inoculated with the same viral load. ConclusionThis study highlights the potential of Ae. scutellaris as a vector for DENV and ZIKV and emphasizes the importance of considering neglected mosquito species in arbovirus transmission and surveillance efforts. Author SummaryDengue and Zika are viral infections caused by arthropod-borne flaviviruses, and spread primarily through the bite of infected Aedes mosquitoes. Most research on DENV and ZIKV transmission has primarily focused on Aedes aegypti and Aedes albopictus while other Aedes species are overlooked, thus the epidemiology of the transmission might be underestimated. With climate change together with species-specific mosquito population reduction interventions these neglected Aedes species could become increasingly important in sustaining virus transmission. In this study, we examined Aedes scutellaris, a mosquito species that co-habitats with Ae. aegypti and Ae. albopictus, to assess its ability to transmit DENV and ZIKV using a combination of blood feeding and intrathoracic injection methods. Our findings show that although Ae. scutellaris had lower initial infection rates due to smaller blood meals, DENV and ZIKV were able to replicate and transmit at levels comparable to Ae. aegypti when exposed to similar virus loads. This highlights the need to study a broader range of species to improve virus control and outbreak prevention strategies.

microbiology↗

bioRxiv2023

Differential intra-host infection kinetics in Aedes aegypti underlie superior transmissibility of African relative to Asian Zika virus

Despite numerous studies highlighting the higher transmissibility of the African Zika virus (ZIKV) lineage compared to the Asian lineage in mosquito vectors, little is known about how the viruses interact with different tissues during the early steps of mosquito infection. To address this gap, we aimed to characterize intra-host infection barriers by combining a tissue-level monitoring of infection using plaque assays and a novel quantitative analysis of single-cell level infection kinetics by in situ immunofluorescent staining. Our results revealed that, in Aedes aegypti, an African ZIKV strain exhibited a higher replication rate across various tissues than an Asian ZIKV strain. This difference was potentially due to a higher virus production in individual cells, faster spread within tissues, or a combination of both factors. Furthermore, we observed that higher bloodmeal titers resulted in a faster viral spread to neighboring cells suggesting that intra-host infection dynamics depend on inoculum size. We also identified a significant bottleneck during midgut infection establishment for both ZIKV lineages, with only a small percentage of the virus population successfully initiating infection. Finally, the in situ immunofluorescent staining technique enabled the examination of virus infection characteristics in different cell types and revealed heterogeneity in viral replication. Together, these findings demonstrate that differences in intra-host infection kinetics underlie differential transmissibility between African and Asian ZIKV lineages. This information could serve as a starting point to further investigate the underlying mechanisms and ultimately inform the development of alternative control strategies. ImportanceThe recent Zika virus (ZIKV) epidemic in the Americas highlights its potential public health threat. While the Asian ZIKV lineage has been identified as the main cause of the epidemic, the African lineage, which has been primarily confined to Africa, has shown evidence of higher transmissibility in Aedes mosquitoes. To gain a deeper understanding of this differential transmissibility, our study employed a combination of tissue-level infection kinetics and single-cell level infection kinetics using in situ immunofluorescent staining. We discovered that the African ZIKV lineage propagates more rapidly and spreads more efficiently within mosquito cells and tissues than its Asian counterpart. This information lays the groundwork for future exploration of the viral and host determinants driving these variations in propagation efficiency.

microbiology↗