Minus Related Pages. An exposure may include contact with: blood or body fluids from a person sick with or who died from EVD, objects contaminated with blood or body fluids of a person sick with or who died from EVD, infected fruit bats and nonhuman primates apes or monkeys , or semen from a man who has recovered from EVD. Related Resources. Signs and Symptoms Treatment Information for Clinicians. Links with this icon indicate that you are leaving the CDC website.
Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website. Enter your email address to subscribe to this blog and receive notifications of new posts by email. Email Address:. Website Powered by WordPress. The Reservoir Fruit bats in Africa are believed to be the primary reservoir. Portal of Exit Ebola leaves its reservoir by contact with body fluids of an infected animal, often by bushmeat hunters.
Transmission Transmission between humans occurs by contact of skin or mucus membranes with the body fluids of an infected person. Portal of Entry Ebola enters the human body through breaks in the skin, including micro-abrasions and splashes on mucus membranes. Vulnerable populations The most vulnerable populations for ebola are defined by their occupation.
References and further reading: Martines, R. Share this: Email. Like this: Like Loading Currently Reading. Subscribe to Blog via Email Enter your email address to subscribe to this blog and receive notifications of new posts by email. Join 1, other followers. Follow Following. Contagions Join 1, other followers. For Clinicians. For Laboratory Personnel.
For Public Health Planners. Communication Resources. Learn More. Links with this icon indicate that you are leaving the CDC website. Sukudu had a population of approximately persons during its Ebola outbreak. Ebola virus was introduced into Sukudu after 7 family members traveled from Sukudu to Koidu Town the capital of the district to care for a sick woman whose husband died from EVD.
These seven family members then traveled back to Sukudu. This chain of transmission in the village ended 6 weeks later Figure 1. Satellite image of village. Quarantined areas are bounded in red, public latrines in yellow. Source: Google Earth Pro. Source: Centers for Disease Control and Prevention. Quarantined households included persons whose exposure to EBOV was inferred based on living in a house or sharing a latrine with an EVD case. In Sukudu, there were several shared latrines near the houses of EVD cases.
Given the poor condition of these sanitary facilities and the close proximity of the households, the DERC decided to quarantine people who shared a latrine with an EVD case. Persons living in the quarantined households of Sukudu were enrolled. The study was conducted from October to January The immunoassay was validated and then applied in a serosurvey that classified seronegative and seropositive persons based on antiglycoprotein immunoglobulin G serology with a cutoff of 4.
Details of the immunoassay validation and serosurvey can be found elsewhere [ 17 ]. Participants were interviewed to obtain sociodemographic information. In instances where confirmed or probable EVD cases had died, we interviewed household members to obtain further information. We collected data on reasons for quarantine and identified those who were quarantined for having lived in the same house or having shared a latrine with an EVD case.
Additional variables were collected from DERC records, including date of symptom onset, date of EVD diagnosis, date of hospitalization, date of death, family relationship, and context of transmission community, health facility, or burial.
The infectious period was defined as the difference between the date of symptom onset and whichever event occurred first: date of hospitalization, date of death, or date of burial.
Uninfected persons were defined as persons quarantined during the outbreak who had a seronegative blood test during the serosurvey. Ebola virus—infected persons were defined as quarantined persons with a seropositive test as well as reported and unrecognized EVD cases. Signs and symptoms consistent with EVD included fever or unexplained bleeding or any 3 of the following: headache, myalgia, rash, vomiting, diarrhea, hiccups, breathing problems, or difficulty swallowing [ 18 ].
Unrecognized EVD cases were defined as seropositive persons who self-reported signs or symptoms consistent with EVD but were not identified during the Ebola outbreak. Ebola virus disease cases were defined as reported and unrecognized EVD cases.
Minimally symptomatic EBOV-infected persons were defined as seropositive persons who did not self-report signs or symptoms consistent with EVD during the Ebola outbreak in Sukudu [ 17 ]. An incubation period was defined as the day period after last infectious contact.
Type 1 links were considered more likely to be true epidemiological links than type 2, and type 2 more likely than type 3. We classified transmission into successive generations based on the temporal relationship of EVD cases established in the epidemiological link assessment described above. The first generation was defined as the number of primary EVD cases in the chain, the second generation was defined as the number of EVD cases who acquired EBOV infection from a member of the first generation, and so forth.
Using the data about the types of epidemiological links and generations of transmission, we reconstructed a complete chain of EBOV transmission in a geospatial array. We used the transmission network to assess randomness of transmission events resulting in minimally symptomatic EBOV infections as follows: We computed the graph theoretic distance [ 19 ] between any 2 minimally symptomatic EBOV infections ie, the number of arcs of the shortest path connecting 2 minimally symptomatic EBOV-infected persons.
We also reconstructed a complete chain of transmission of reported EVD cases in a temporal array based on onset of symptoms. We excluded persons with minimally symptomatic EBOV infections and unrecognized EVD cases from the temporal array because persons with minimally symptomatic EBOV infections were assumed to be noninfectious, and unrecognized EVD cases were not asked to recall their date of symptom onset.
For the epidemiologic analysis, we included the following covariates: age, sex, occupation, educational level, and reason for being quarantined. The mean and standard deviations SDs of the infectious period for EVD cases were described, and we used the t test to calculate differences in means.
Additional cluster-based analyses were conducted to identify risk factors for reported EVD among uninfected, quarantined persons Supplementary Data 1.
For the transmission chain analysis, we estimated the number of EVD cases in each successive generation of transmission. To estimate the effective reproduction number, R t , for each generation of transmission, we divided the total number of new EVD cases in each generation by the number of EVD cases in the previous generation. For the first generation, we calculated binomial exact confidence intervals using the number infected out of the number exposed.
Poisson exact confidence intervals were calculated for subsequent generations in the absence of a known denominator. We also used a permutation test to assess whether the mean nearest neighbor distance between minimally symptomatic EBOV infections in the transmission chain was smaller than would be expected if the pattern of minimally symptomatic infections was random Supplementary Data 2.
Finally, we repeated the analysis for each method of assessment of linkages Supplementary Data 2. These analyses were performed in R version 3. Twenty-five houses were quarantined. A flow diagram of Ebola virus transmission among the quarantined persons. Ebola virus was transmitted through the village during a 6-week period over 4 generations of transmission. The overall number of EBOV infections cluster size was
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