scholarly journals Vertical transmission of zika virus in Aedes albopictus

2020 ◽  
Vol 14 (10) ◽  
pp. e0008776
Author(s):  
Zetian Lai ◽  
Tengfei Zhou ◽  
Jiayong Zhou ◽  
Shuang Liu ◽  
Ye Xu ◽  
...  
Keyword(s):  
Vertical Transmission ◽  
Aedes Albopictus ◽  
Reverse Transcription ◽  
Zika Virus ◽  
Transmission Rate ◽  
Horizontal Transmission ◽  
Infection Rates ◽  
Transmission Rates ◽  
Suckling Mice ◽  
Reverse Transcription Pcr

Background Zika virus (ZIKV) is an arthropod-borne flavivirus transmitted by Aedes mosquitoes. Aedes albopictus is an important vector of ZIKV worldwide. To date, most experiments have focused on the vertical transmission of ZIKV in Ae. aegypti, while studies on Ae. albopictus are very limited. To explore vertical transmission in Ae. albopictus, a series of laboratory studies were carried out. Methodology/Principal findings In this study, Ae. albopictus were blood-fed with ZIKV-infectious blood, and the ovaries and offspring viral infection rates were analyzed by reverse transcription PCR (RT-PCR), real-time reverse transcription PCR (RT-qPCR) and immunohistochemistry (IHC). ZIKV was detected in the ovaries and oviposited eggs in two gonotrophic cycles. The minimum filial egg infection rates in two gonotrophic cycles were 2.06% and 0.69%, and the effective population transmission rate was 1.87%. The hatching, pupation, and emergence rates of infected offspring were not significantly different from those of uninfected offspring, indicating that ZIKV did not prevent the offspring from completing the growth and development process. ZIKV was detected in three of thirteen C57BL/6 suckling mice bitten by ZIKV-positive F1 females, and the viremia persisted for at least seven days. Conclusions/Significance ZIKV can be vertically transmitted in Ae. albopictus via transovarial transmission. The vertical transmission rates in F1 eggs and adults were 2.06% and 1.87%, respectively. Even though the vertical transmission rates were low, the female mosquitoes infected via the congenital route horizontally transmitted ZIKV to suckling mice through bloodsucking. This is the first experimental evidence of offspring with vertically transmitted ZIKV initiating new horizontal transmission. The present study deepens the understanding of the vertical transmission of flaviviruses in Aedes mosquitoes and sheds light on the prevention and control of mosquito-borne diseases.

scholarly journals Transmission Potential of Zika Virus by Aedes aegypti (Diptera: Culicidae) and Ae. mediovittatus (Diptera: Culicidae) Populations From Puerto Rico

2021 ◽  
Author(s):  
Rebecca A Zimler ◽  
Donald A Yee ◽  
Barry W Alto
Keyword(s):  
Puerto Rico ◽  
Aedes Aegypti ◽  
Zika Virus ◽  
Mosquito Species ◽  
The United States ◽  
Infection Rates ◽  
Transmission Potential ◽  
Transmission Rates ◽  
Higher Doses ◽  
Local Transmission

Abstract Recurrence of local transmission of Zika virus in Puerto Rico is a major public health risk to the United States, where mosquitoes Aedes aegypti (Linnaeus) and Aedes mediovittatus (Coquillett) are abundant. To determine the extent to which Ae. mediovittatus are capable of transmitting Zika virus and the influence of viremia, we evaluated infection and transmission in Ae. mediovittatus and Ae. aegypti from Puerto Rico using serial dilutions of infectious blood. Higher doses of infectious blood resulted in greater infection rates in both mosquitoes. Aedes aegypti females were up to twice as susceptible to infection than Ae. mediovittatus, indicating a more effective midgut infection barrier in the latter mosquito species. Aedes aegypti exhibited higher disseminated infection (40–95%) than Ae. mediovittatus (<5%), suggesting a substantial midgut escape barrier in Ae. mediovittatus. For Ae. aegypti, transmission rates were low over a range of doses of Zika virus ingested, suggesting substantial salivary gland barriers.

scholarly journals Simulated folivory increases vertical transmission of fungal endophytes that deter herbivores and alter tolerance to herbivory in Poa autumnalis

2020 ◽  
Vol 125 (6) ◽  
pp. 981-991 ◽  
Author(s):  
Pedro E Gundel ◽  
Prudence Sun ◽  
Nikki D Charlton ◽  
Carolyn A Young ◽  
Tom E X Miller ◽  
...  
Keyword(s):  
Vertical Transmission ◽  
Transmission Rate ◽  
Horizontal Transmission ◽  
Fungal Endophytes ◽  
Natural Populations ◽  
Plant Tolerance ◽  
Hyphal Density ◽  
Symbiotic Fungi ◽  
Symbiont Transmission ◽  
Fitness Benefits

Abstract Background and Aims The processes that maintain variation in the prevalence of symbioses within host populations are not well understood. While the fitness benefits of symbiosis have clearly been shown to drive changes in symbiont prevalence, the rate of transmission has been less well studied. Many grasses host symbiotic fungi (Epichloë spp.), which can be transmitted vertically to seeds or horizontally via spores. These symbionts may protect plants against herbivores by producing alkaloids or by increasing tolerance to damage. Therefore, herbivory may be a key ecological factor that alters symbiont prevalence within host populations by affecting either symbiont benefits to host fitness or the symbiont transmission rate. Here, we addressed the following questions: Does symbiont presence modulate plant tolerance to herbivory? Does folivory increase symbiont vertical transmission to seeds or hyphal density in seedlings? Do plants with symbiont horizontal transmission have lower rates of vertical transmission than plants lacking horizontal transmission? Methods We studied the grass Poa autumnalis and its symbiotic fungi in the genus Epichloë. We measured plant fitness (survival, growth, reproduction) and symbiont transmission to seeds following simulated folivory in a 3-year common garden experiment and surveyed natural populations that varied in mode of symbiont transmission. Key Results Poa autumnalis hosted two Epichloë taxa, an undescribed vertically transmitted Epichloë sp. PauTG-1 and E. typhina subsp. poae with both vertical and horizontal transmission. Simulated folivory reduced plant survival, but endophyte presence increased tolerance to damage and boosted fitness. Folivory increased vertical transmission and hyphal density within seedlings, suggesting induced protection for progeny of damaged plants. Across natural populations, the prevalence of vertical transmission did not correlate with symbiont prevalence or differ with mode of transmission. Conclusions Herbivory not only mediated the reproductive fitness benefits of symbiosis, but also promoted symbiosis prevalence by increasing vertical transmission of the fungus to the next generation. Our results reveal a new mechanism by which herbivores could influence the prevalence of microbial symbionts in host populations.

scholarly journals Evidence of Zika virus horizontal and vertical transmission in Aedes albopictus from Spain but not infectious virus in saliva of the progeny

2020 ◽  
Vol 9 (1) ◽  
pp. 2236-2244
Author(s):  
Ana I. Nuñez ◽  
Sandra Talavera ◽  
Lotty Birnberg ◽  
Raquel Rivas ◽  
Núria Pujol ◽  
...  
Keyword(s):  
Vertical Transmission ◽  
Aedes Albopictus ◽  
Zika Virus ◽  
Infectious Virus

Vector Competence and Vertical Transmission of Zika Virus in Aedes albopictus (Diptera: Culicidae)

2020 ◽  
Vol 20 (5) ◽  
pp. 374-379 ◽  
Author(s):  
Xiaoxia Guo ◽  
Chunxiao Li ◽  
Yongqiang Deng ◽  
Yuting Jiang ◽  
Aijuan Sun ◽  
...  
Keyword(s):  
Vertical Transmission ◽  
Aedes Albopictus ◽  
Zika Virus ◽  
Vector Competence

scholarly journals Comparison of Four Serological Methods and Two Reverse Transcription-PCR Assays for Diagnosis and Surveillance of Zika Virus Infection

2018 ◽  
Vol 56 (3) ◽  
Author(s):  
Angel Balmaseda ◽  
José Victor Zambrana ◽  
Damaris Collado ◽  
Nadezna García ◽  
Saira Saborío ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Zika Virus ◽  
Clinical Manifestations ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Emerging Infections ◽  
Rt Pcr ◽  
Convalescent Phase ◽  
Reverse Transcription Pcr ◽  
Pcr Assays

ABSTRACTZika virus (ZIKV) is a mosquito-borne flavivirus that is responsible for recent explosive epidemics in the Americas. Notably, ZIKV infection during pregnancy has been found to cause congenital birth defects, including microcephaly, and ZIKV has been associated with Guillain-Barré syndrome in adults. Diagnosis and surveillance of Zika in the Americas have been challenging due to similar clinical manifestations and extensive antibody cross-reactivity with endemic flaviviral diseases, such as dengue. We evaluated four serological and two reverse transcription-PCR (RT-PCR) methods in acute-phase (mean day, 1.8), early-convalescent-phase (mean day, 16.7), and late-convalescent-phase (mean, ~7 months) samples from the same individuals in a long-term pediatric cohort study in Nicaragua. Well-characterized samples from 301 cases of Zika, dengue, or non-Zika, nondengue febrile illnesses were tested. Compared to a composite reference, an in-house IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) and the NIAID-Biodefense and Emerging Infections (BEI) MAC-ELISA measuring IgM yielded sensitivities of 94.5% and 70.1% and specificities of 85.6% and 82.8%, respectively. The NS1 blockade-of-binding ELISA measuring anti-ZIKV NS1 antibody levels yielded sensitivities of 85.0% and 96.5% and specificities of 91.4% and 92.6% at early and late convalescence, respectively. An inhibition ELISA detecting total anti-ZIKV antibodies had sensitivity and specificity values of 68.3% and 58.3% for diagnosis and 94.0% and 98.6% for measuring annual infection incidence. Finally, the ZCD and Trioplex real-time RT-PCR assays detecting Zika, chikungunya, and dengue viruses both yielded a sensitivity of 96.1% and specificity of 100%. Together, these assays resolve the urgent need for diagnostic and surveillance tools for countries affected by Zika virus infections.

scholarly journals Modeling intra-mosquito dynamics of Zika virus and its dose-dependence confirms the low epidemic potential of Aedes albopictus

2020 ◽  
Vol 16 (12) ◽  
pp. e1009068
Author(s):  
Sebastian Lequime ◽  
Jean-Sébastien Dehecq ◽  
Séverine Matheus ◽  
Franck de Laval ◽  
Lionel Almeras ◽  
...  
Keyword(s):  
Aedes Albopictus ◽  
Zika Virus ◽  
Large Scale ◽  
Virus Transmission ◽  
Central Africa ◽  
Systemic Infection ◽  
Dose Dependence ◽  
Risk Level ◽  
Infection Rates ◽  
Simulated Environment

Originating from African forests, Zika virus (ZIKV) has now emerged worldwide in urbanized areas, mainly transmitted by Aedes aegypti mosquitoes. Although Aedes albopictus can transmit ZIKV experimentally and was suspected to be a ZIKV vector in Central Africa, the potential of this species to sustain virus transmission was yet to be uncovered until the end of 2019, when several autochthonous transmissions of the virus vectored by Ae. albopictus occurred in France. Aside from these few locally acquired ZIKV infections, most territories colonized by Ae. albopictus have been spared so far. The risk level of ZIKV emergence in these areas remains however an open question. To assess Ae. albopictus’ vector potential for ZIKV and identify key virus outbreak predictors, we built a complete framework using the complementary combination of (i) dose-dependent experimental Ae. albopictus exposure to ZIKV followed by time-dependent assessment of infection and systemic infection rates, (ii) modeling of intra-human ZIKV viremia dynamics, and (iii) in silico epidemiological simulations using an Agent-Based Model. The highest risk of transmission occurred during the pre-symptomatic stage of the disease, at the peak of viremia. At this dose, mosquito infection probability was estimated to be 20%, and 21 days were required to reach the median systemic infection rates. Mosquito population origin, either temperate or tropical, had no impact on infection rates or intra-host virus dynamic. Despite these unfavorable characteristics for transmission, Ae. albopictus was still able to trigger and yield large outbreaks in a simulated environment in the presence of sufficiently high mosquito biting rates. Our results reveal a low but existing epidemic potential of Ae. albopictus for ZIKV, that might explain the absence of large scale ZIKV epidemics so far in territories occupied only by Ae. albopictus. They nevertheless support active surveillance and eradication programs in these territories to maintain the risk of emergence to a low level.

scholarly journals Highly Efficient Vertical Transmission for Zika Virus in Aedes aegypti after Long Extrinsic Incubation Time

Pathogens ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 366 ◽  
Author(s):  
Menchie Manuel ◽  
Dorothée Missé ◽  
Julien Pompon
Keyword(s):  
Viral Load ◽  
Aedes Aegypti ◽  
Vertical Transmission ◽  
Incubation Time ◽  
Zika Virus ◽  
Horizontal Transmission ◽  
Oral Infection ◽  
Gonotrophic Cycle ◽  
Pooled Samples ◽  
Shed Light

While the Zika virus (ZIKV) 2014–2017 pandemic has subsided, there remains active transmission. Apart from horizontal transmission to humans, the main vector Aedes aegypti can transmit the virus vertically from mother to offspring. Large variation in vertical transmission (VT) efficiency between studies indicates the influence of parameters, which remain to be characterized. To determine the roles of extrinsic incubation time and gonotrophic cycle, we deployed an experimental design that quantifies ZIKV in individual progeny and larvae. We observed an early infection of ovaries that exponentially progressed. We quantified VT rate, filial infection rate, and viral load per infected larvae at 10 days post oral infection (d.p.i.) on the second gonotrophic cycle and at 17 d.p.i. on the second and third gonotrophic cycle. As compared to previous reports that studied pooled samples, we detected a relatively high VT efficiency from 1.79% at 10 d.p.i. and second gonotrophic cycle to 66% at 17 d.p.i. and second gonotrophic cycle. At 17 d.p.i., viral load largely varied and averaged around 800 genomic RNA (gRNA) copies. Longer incubation time and fewer gonotrophic cycles promoted VT. These results shed light on the mechanism of VT, how environmental conditions favor VT, and whether VT can maintain ZIKV circulation.

scholarly journals Elucidation of the Transmission Patterns of an Insect-Borne Bacterium

2003 ◽  
Vol 69 (8) ◽  
pp. 4403-4407 ◽  
Author(s):  
A. C. Darby ◽  
A. E. Douglas
Keyword(s):  
Vertical Transmission ◽  
Acyrthosiphon Pisum ◽  
Deterministic Model ◽  
Transmission Rate ◽  
Horizontal Transmission ◽  
Natural Populations ◽  
Oral Route ◽  
Pea Aphid ◽  
Diagnostic Pcr ◽  
Modes Of Transmission

ABSTRACT Quantitative data on modes of transmission are a crucial element in understanding the ecology of microorganisms associated with animals. We investigated the transmission patterns of a γ-proteobacterium informally known as pea aphid Bemisia-like symbiont (PABS), also known as T-type, which is widely but not universally distributed in natural populations of the pea aphid, Acyrthosiphon pisum. The vertical transmission of PABS to asexual and sexual morphs and sexually produced eggs was demonstrated by a diagnostic PCR-based assay, and the maximum estimated failure rate was 2%. Aphids naturally lacking PABS acquired PABS bacteria administered via the diet, and the infection persisted by vertical transmission for at least three aphid generations. PABS was also detected in two of five aphid honeydew samples tested and in all five siphuncular fluid samples tested but in none of 15 samples of salivary secretions from PABS-positive aphids. However, PABS-negative aphids did not acquire PABS when they were cocultured with PABS-positive aphids; the maximal estimated level of horizontal transmission was 18%. A deterministic model indicated that the force of infection by a horizontal transmission rate of 3% is sufficient to maintain a previously described estimate of the prevalence of PABS-positive aphids (37%), if the vertical transmission rate is 98%. We concluded that PABS infections in A. pisum can be maintained by high vertical transmission rates and occasional horizontal transmission, possibly via the oral route, in the absence of selection either for or against aphids bearing this bacterium.

Rising mother-to-child HIV transmission in a resource-limited breastfeeding population

2010 ◽  
Vol 40 (2) ◽  
pp. 70-73 ◽  
Author(s):  
Felicity Zvanyadza Gumbo ◽  
Nyaradzai Edith Kurewa ◽  
Gwendoline Quintoline Kandawasvika ◽  
Kerina Duri ◽  
Munyaradzi Paul Mapingure ◽  
...  
Keyword(s):  
Single Dose ◽  
Vertical Transmission ◽  
Hiv Transmission ◽  
Transmission Rate ◽  
Transmission Rates ◽  
Time Points ◽  
Resource Limited ◽  
Single Dose Nevirapine ◽  
Blood Specimens ◽  
Mother To Child

The objective of this study was to determine mother to child HIV transmission rates at different time points in a breastfeeding cohort enrolled in a single dose nevirapine program in Harare, Zimbabwe. Between 2002–2004, 434 HIV-positive mothers and their infants were recruited and followed up from delivery to 15 months. Infant blood specimens were collected for HIV testing at these time points. The majority of the patients (78%) received single dose nevirapine. The overall HIV transmission rate was 21.8% (17.8–25.8). Receiving single dose nevirapine was protective against HIV vertical transmission although statistically insignificant (relative risk: 0.76; 95% CI: 0.49–1.19). Breastfeeding was not found to be associated with HIV vertical transmission ( P = 0.612). In this resource-limited setting, HIV transmission rates are high. Efforts to use more efficacious regimens to arrest HIV vertical transmission are required.

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