Search Results (5)

Mosquito-borne arboviruses include several pathogens that are responsible for many diseases of significant public health burden. Mosquitoes also host many insect-specific viruses that cannot replicate in vertebrate cells. These insect-specific viruses persist in nature predominantly via vertical transmission (VT), and they exhibit high VT rates (VTRs). Cell-fusing agent virus (CFAV), an insect-specific orthoflavivirus, shows high VTRs in naturally infected mosquitoes but not in artificially infected mosquitoes. To determine whether the high VTRs are due to transovarial transmission, we investigated VT and ovary infection patterns in naturally CFAV-infected Aedes aegypti (Bangkok) mosquitoes. VT was monitored by detecting CFAV among the progeny by reverse-transcription polymerase chain reaction and ovary infection was determined by in situ hybridization using a virus-specific probe. We showed that in CFAV-positive mosquitoes, ovarian follicles were infected, suggesting that VT occurs by transovarial transmission in naturally infected mosquitoes. Additionally, mosquitoes harbored dormant, non-replicative CFAV that remained below the detection level. These results suggested that CFAV persists via VT in nature and has the potential to remain dormant in diapausing mosquitoes during unfavorable conditions. Understanding this VT mechanism is crucial for comprehending the persistence of insect-specific viruses (and potentially dual-host arboviruses) in their natural environment. Full article

Lymphomas related to HIV are generally aggressive and have a poor prognosis, despite the use of combined antiretroviral therapy (cART) and effective chemotherapy treatment. To determine survival and prognostic factors in children and adolescents living with HIV (CLWH) in Rio de Janeiro (RJ), Brazil, who developed lymphomas, we performed a retrospective and observational study of vertically infected CLWH aged from 0 to 20 incomplete years during1995 to 2018 at five reference centers for cancer and HIV/AIDS treatment. Of the 25 lymphomas, 19 were AIDS-defining malignancies (ADM) and 6 were non-AIDS-defining malignancies (NADM). The 5-year overall survival (OS) and 5-year event-free survival (EFS) probabilities were both 32.00% (95% CI = 13.72–50.23%), and the 5-year disease-free survival (DFS) probability was 53.30% (95% CI = 28.02–78.58%). In the multivariate Cox regression analysis, performance status 4 (PS 4) was considered a poor prognostic factor for OS (HR 4.85, 95% CI = 1.81–12.97, p = 0.002) and EFS (HR 4.95, 95% CI = 1.84–13.34, p = 0.002). For the DFS, higher CD4+ T-cell counts were considered a better prognostic factor (HR 0.86, 95% CI = 0.76–0.97, p = 0.017) in the multivariate Cox regression analysis. This study demonstrates, for the first time, survival and prognostic factors for CLWH who developed lymphomas in RJ, Brazil. Full article

The incidence of cancer in children living with HIV (CLWH) is high and lymphomas are the most common type of cancer in this population. The combined antiretroviral therapy (cART) changed the natural history of HIV infection. To determine the incidence and profile of these CLWH malignancies in Rio de Janeiro (RJ), Brazil, we conducted a retrospective and observational study of vertically infected CLWH, ranging from 0–20 incomplete years, from 1995 to 2018, at five reference centers. The study period was divided into three eras in accordance with the widespread use of cART in Brazil. 1306 patients were included. Of the 25 lymphomas found, 19 were AIDS-defining malignancies (ADM); 6 were non-AIDS-defining malignancies (NADM). The incidence rate (IR) of lymphoma developing was 1.70 per 1000 children-year (95% CI 1.09–2.50). ADM development IR decreased from 2.09–1.75–0.19 per 1000 children-year (p < 0.001) through cART eras. Cumulative Nelson–Aalen hazards of developing ADM over a 20-year period were 3.73% in the Early-cART era, 3.07% in the Mid-cART era, and 0.32% in the Late-cART era (p = 0.013). This study demonstrates the IR of lymphoma in CLWH in RJ, Brazil, as well as the benefit of cART in reducing ADM and death occurrence in the Post-cART era. Full article

Vertical transmission (VT) is a phenomenon of vector-borne diseases where a pathogen is transferred from an infected arthropod mother to her offspring. For mosquito-borne flavi- and alphaviruses, VT is commonly viewed as rare; however, both field and experimental studies report on vertical transmission efficiency to a notably varying degree. It is likely that this reflects the different experimental methods used to test vertical transmission efficiency as well as differences between virus–vector combinations. There are very few investigations of the VT of an alphavirus in a Culex vector. Sindbis virus (SINV) is an arthritogenic alphavirus that utilizes Culex species as main vectors both in the summer transmission season and for its persistence over the winter period in northern latitudes. In this study, we investigated the vertical transmission of the SINV in Culex vectors, both in the field and in experimental settings. The detection of SINV RNA in field-collected egg rafts and emerging adults shows that vertical transmission takes place in the field. Experimentally infected females gave rise to adult offspring containing SINV RNA at emergence; however, three to four weeks after emergence none of the offspring contained SINV RNA. This study shows that vertical transmission may be connected to SINV’s ability to persist throughout northern winters and also highlights many aspects of viral replication that need further study. Full article

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. Full article