The last search was conducted on 13 January 2016. We extracted all articles that reported either seroprevalence among asymptomatic contacts or prevalence of symptoms among antibody-positive survivors. To estimate the asymptomatic proportion, searches were conducted in PubMed using the term Ebola plus any of the following terms: seroprevalence, serosurvey, asymptomatic, mild, subclinical, or. For data beyond household SAR, we direct readers to a recent summary of Ebola transmissibility. Household SAR estimates were recorded by type of exposure (eg, direct contact, nursing care) where such information was available. Where denominators (number of exposures) were not reported but the number of case patients and SAR were available, the denominator was calculated acknowledging limits of significant digits (6 case patients and SAR of 0.072 in first generation and 3 case patients and SAR of 0.04 in second generation of transmission in Yamolembia 24 case patients and SAR of 0.025 overall ). The publication must report a numerator and denominator among household contacts, or at least 2 of numerator, denominator, and SAR. We extracted all articles with original data for estimating the household SAR for Ebola subtypes Sudan or Zaire in African outbreaks. To estimate the household SAR, searches were conducted in PubMed using the term Ebola plus any of the following: household secondary attack rate, household transmission, contact transmission, contact attack rate, or family transmission. The denominator of the SAR is the number of exposed contacts, and the numerator is the number of those exposed contacts who develop disease. The SAR is the probability that an exposed susceptible person develops disease over the duration of infectiousness in a case patient. Transmissibility is measured by the household secondary attack rate (SAR). Most of the data described are from earlier outbreaks, as very few data are available on the epidemic in West Africa. We also present estimates of the asymptomatic proportion of the virus from serosurveys. We present a meta-analytic summary of transmission within households, disaggregated by type of exposure. In this article, we summarize the transmissibility and pathogenicity of EV. The proportion of transmissions occurring asymptomatically has an important bearing on our ability to contain an outbreak, with containment measures being less effective if asymptomatic individuals are infectious. Very little is known about the impact of asymptomatic infection on Ebola outbreaks, including the level of pathogenicity of EV, defined as the proportion of Ebola infections that are symptomatic. To understand the first 2 elements, household studies are especially useful as contacts are clearly defined and remain fairly constant across cultural settings. In addition, (4) availability of prophylactic agents, therapeutics, and vaccines is key. įraser et al propose a framework where the key elements that impact our ability to contain an outbreak are (1) the disease generation time, which is the mean time between infection of an individual and infection of secondary cases, (2) the transmissibility of the virus, and (3) the proportion of asymptomatic transmissions. In contrast, the 2013–2016 outbreak in West Africa was larger than all prior outbreaks combined. Such an approach has historically been effective for ending Ebola outbreaks. The preferred strategy of surveillance and containment is achieved through isolation of cases, intense contact tracing, and active monitoring. For emerging infectious agents, such as Ebola virus (EV), effective prophylactic agents, therapeutics, and vaccines have not been available.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |