Can Ebola virus evolve to be less virulent in humans?

Sofonea, Mircea T.; Aldakak, Lafi; Boullosa, Luis Fernando; Alizon, Samuel

doi:10.1111/jeb.13229

Cited by 8 publications

(4 citation statements)

References 57 publications

(87 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This increased virulence is attributable to viral evolution, as experiments in in vitro and animal systems suggested that the coordinated expression of eight genes unique to the 1918 virus was responsible for the increased lethality [35,36]. For other human pathogens, such as smallpox, virulence fluctuated wildly from one wave to the next [37,38], with the high-virulence ("variola major") strains showing functional differences from the low virulence ("variola minor") strains [39,40] in in vitro and animal studies. The instability of smallpox virulence over time contradicts the notion of obligatory viral attenuation and may foreshadow similar behavior during the current pandemic.…”

Section: Introductionmentioning

confidence: 99%

Endemicity Is Not a Victory: The Unmitigated Downside Risks of Widespread SARS-CoV-2 Transmission

Stoddard¹,

Novokhodko

Sarkar

et al. 2022

COVID

View full text Add to dashboard Cite

The strategy of relying solely on current SARS-CoV-2 vaccines to halt SARS-CoV-2 transmission has proven infeasible. In response, many public-health authorities have advocated for using vaccines to limit mortality while permitting unchecked SARS-CoV-2 spread (“learning to live with the disease”). The feasibility of this strategy critically depends on the infection fatality rate (IFR) of SARS-CoV-2. An expectation exists that the IFR will decrease due to selection against virulence. In this work, we perform a viral fitness estimation to examine the basis for this expectation. Our findings suggest large increases in virulence for SARS-CoV-2 would result in minimal loss of transmissibility, implying that the IFR may vary freely under neutral evolutionary drift. We use an SEIRS model framework to examine the effect of hypothetical changes in the IFR on steady-state death tolls under COVID-19 endemicity. Our modeling suggests that endemic SARS-CoV-2 implies vast transmission resulting in yearly US COVID-19 death tolls numbering in the hundreds of thousands under many plausible scenarios, with even modest increases in the IFR leading to unsustainable mortality burdens. Our findings highlight the importance of enacting a concerted strategy and continued development of biomedical interventions to suppress SARS-CoV-2 transmission and slow its evolution.

show abstract

Section: Introductionmentioning

confidence: 99%

Endemicity Is Not a Victory: The Unmitigated Downside Risks of Widespread SARS-CoV-2 Transmission

Stoddard¹,

Novokhodko

Sarkar

et al. 2022

COVID

View full text Add to dashboard Cite

show abstract

“…As a consequence, our modelling result is scale-free and applies to any size of mosquito population, or any spatial range. Moreover, our reproduction number represents solely the lower bound of the true basic reproduction number, as the model does not account for any other transmission route - namely horizontal, from mammal hosts to mosquitoes, and vertical, from female mosquitoes to eggs [41].…”

Section: Resultsmentioning

confidence: 99%

West Nile virus is transmitted within mosquito populations through infectious mosquito excreta

Hamel,

Narpon,

Serrato-Pomar

et al. 2024

Preprint

View full text Add to dashboard Cite

Understanding transmission routes of arboviruses is key to control their epidemiology and global health burden. Using West Nile virus and Culex mosquitoes, we tested whether arboviruses are transmitted through mosquito excreta. First, we determined the presence of infectious virions in excreta and quantified a high concentration of infectious units per excreta. Second, we showed that virion excretion starts early after oral infection and remains constant for a long period, regardless of mosquito infection level. These results highlight the infectiousness of excreta from infected mosquitoes. Third, we found that both larvae and pupae were susceptible to infection, although pupae were highly permissive. Forth, we established the proof-of-concept that immature mosquitoes can be infected by infectious excreta, demonstrating a new excreta-mediated mode of transmission. Finally, by mathematically modelling excreta-mediated transmission in the field, we demonstrated its potential impact on arbovirus epidemiology. Our study uncovers a new route of transmission for arboviruses, unveiling mechanisms of viral maintenance in mosquito reservoirs and of vector species shift that contribute to zoonotic emergence.

show abstract

“…For example, a spyware cyber attack, which aims to maximize the amount of data siphoned from a computer over an extended period of time, (where fitness might be measured as the volume of leaked data) would not accurately be compared to Ebola virus. Ebola virus maximizes its total transmission by destroying its host quickly via hemorrhaging [35]. Such fast and obvious harm would undermine the intent of spyware, which cannot continue to gather data from an incapacitated computer.…”

Section: Framing the Context Of Defensementioning

confidence: 99%