During the mid-transmission period of the Ebola virus disease (EVD) outbreak in Sierra Leone, a 1... more During the mid-transmission period of the Ebola virus disease (EVD) outbreak in Sierra Leone, a 19-year-old pregnant woman, who was a petty trader in a health facility in Freetown, noticing no fetal movement for the past 3 days, reported to a health facility. Medical history and laboratory testing showed no abnormalities except that she was positive for sickle cell. She was not known to any surveillance team of having any epidemiological link to EVD case. She was induced with oral medications as well as IV infusion. EVD test showed that the fetus was positive to EVD with a high threshold value of 21, while the woman was negative for EVD with a threshold value of 42. The woman was positive to EVD IgG but negative to EVD IgM by ELISA technique. This is a rare EVD case in the period of medium transmission. We conclude that the woman may have come into contact with a low dose of virus not enough to cause a full blown EVD and that her immune system was able to stop the virus from further...
Background: The heterogeneity of the pre-antiretroviral (pre-ART) population calls for more granu... more Background: The heterogeneity of the pre-antiretroviral (pre-ART) population calls for more granular depictions of the cascade of HIV care. Methods: We studied a prospective cohort of persons newly diagnosed with HIV infection from a single center in Freetown, Sierra Leone, over a 12-month period and then traced those persons who were lost to follow-up (LTFU) during pre-ART care (before ART initiation). ART eligibility was based on a CD4 cell count result of < 350 mm/cells and/or WHO clinical stage 3 or 4. Persons who attended an appointment in the final three months were considered to be retained in care. Adherence to ART was measured using pharmacy refill dates. "Effective HIV care" was defined as completion of the cascade of care at 12-months regardless of whether patients are on ART. Tracing outcomes were obtained for those who were LTFU during pre-ART care. Results: 408 persons newly diagnosed with HIV infection were screened, 338 were enrolled, and 255 persons were staged for ART. ART-ineligible persons had higher retention rates than ART-eligible persons (59.6% vs 41.8%, p=0.03). 77 (22.8%) of 338 persons received effective HIV care. Most attrition (61.9%) occurred with persons during pre-ART care. 123 of 138 persons (89.1%) who were LTFU prior to ART initiation were found, and 91 of those 123 (74.0%) were alive. Of the 74 persons who were alive and described their engagement in care, 40 (54.1%) stopped care. Nearly half (42.5%) of those 40 stopped after assessment of ART-eligibility but before ART initiation. The main limitation of this study was the lack of tracing outcomes for those lost during ART care. Conclusions: The majority of the pre-ART LTFU population stopped their care, particularly after ART-eligibility but before ART initiation. Interventions to hasten ART initiation and retain this at-risk group may have significant downstream impact on effective HIV care
Background The 2014â 2016 Ebola virus epidemic in West Africa was the largest outbreak of Ebola v... more Background The 2014â 2016 Ebola virus epidemic in West Africa was the largest outbreak of Ebola virus disease (EVD) in history. Clarifying the influence of other prevalent diseases such as human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) will help improve treatment and supportive care of patients with EVD. Case presentation We examined HIV and hepatitis C virus (HCV) antibody prevalence among suspected EVD cases from the Sierra Leone-China Friendship Biological Safety Laboratory during the epidemic in Sierra Leone. HIV and HCV antibodies were tested in 678 EVD-negative samples by enzyme-linked immunosorbent assay. A high HIV prevalence (17.6%) and low HCV prevalence (0.22%) were observed among the suspected cases. Notably, we found decreased HIV positive rates among the suspected cases over the course of the epidemic. This suggests a potentially beneficial effect of an improved public health system after assistance from the World Health Organ...
OBJECTIVE People in Western Africa suffer greatly from febrile jaundice, which is caused by a var... more OBJECTIVE People in Western Africa suffer greatly from febrile jaundice, which is caused by a variety of pathogens. However, yellow fever virus (YFV) is the only pathogen under surveillance in Sierra Leone owing to the undeveloped medical and public health system there. Most of the results of YFV identification are negative. Elucidation of the pathogen spectrum is required to reduce the prevalence of febrile jaundice. METHODS In the present study, we used Ion Torrent semiconductor sequencing to profile the pathogen spectrum in archived YFV-negative sera from 96 patients in Sierra Leone who presented with unexplained febrile jaundice. RESULTS The most frequently identified sequencing reads belonged to the following pathogens: cytomegalovirus (89.58%), Epstein-Barr virus (55.21%), hepatitis C virus (34.38%), rhinovirus (28.13%), hepatitis A virus (20.83%), coxsackievirus (10.42%), Ebola virus (8.33%), hepatitis E virus (8.33%), lyssavirus (4.17%), leptospirosis (4.17%), chikungunya vi...
SAHARA J : journal of Social Aspects of HIV/AIDS Research Alliance, Dec 1, 2018
Evaluations of community-based antiretroviral therapy (ART) programmes have demonstrated positive... more Evaluations of community-based antiretroviral therapy (ART) programmes have demonstrated positive outcomes, but little is known about the impact of tapering community-based ART. The objective of this study was to assess 24-month HIV retention outcomes of a community-based ART programme and its tapered visit frequency in Koidu City, Sierra Leone. This retrospective, quasi-experimental study compared outcomes of 52 HIV-infected persons initiated on community-based ART against 91 HIV-infected persons receiving the standard of care from November 2009 to February 2013. The community-based ART pilot programme was designed to strengthen the standard of care through a comprehensive, patient-centred case management strategy. The strategy included medical, educational, psychological, social, and economic support. Starting in October 2011, the frequency of home visits was tapered from twice daily every day per week to once daily three days per week. Outcomes were retention in care at 12 and 24...
This study aimed to investigate the serological characteristics of Ebola virus (EBOV) infection d... more This study aimed to investigate the serological characteristics of Ebola virus (EBOV) infection during the late phase of the Ebola outbreak in Sierra Leone. In total, 877 blood samples from 694 suspected Ebola virus disease (EVD) cases assessed from March to December 2015, were analyzed via real-time reverse transcription polymerase chain reaction (RT-PCR) for viral RNA and enzyme-linked immunosorbent assay (ELISA) and Luminex to detect antibodies against EBOV. Viral load and EBOV-specific IgM/IgG titers displayed a declining trend during March to December 2015. Viral RNA load decreased rapidly at earlier stages after disease onset, while EBOV-specific IgM and IgG still persisted in 58.1% (18/31) and 93.5% (29/31) of the confirmed EVD patients and in 3.8% (25/663) and 17.8% (118/663) of the RNA-negative suspected patients in the later phase, respectively. Dynamic analysis of longitudinally collected samples from eight EVD patients revealed typically reversed trends of declining vira...
A serosurvey of anti-Ebola Zaire virus nucleoprotein IgG prevalence was carried out among Ebola v... more A serosurvey of anti-Ebola Zaire virus nucleoprotein IgG prevalence was carried out among Ebola virus disease survivors and their Community Contacts in Bombali District, Sierra Leone. Our data suggest that the specie of Ebola virus () responsible of the 2013-2016 epidemic in West Africa may cause mild or asymptomatic infection in a proportion of cases, possibly due to an efficient immune response.
Sierra Leone was the most severely affected country in Western Africa during the 2013-2016 outbre... more Sierra Leone was the most severely affected country in Western Africa during the 2013-2016 outbreak of Ebola virus disease (EVD). Previous genome surveillance studies have revealed the origin, diversity, and evolutionary dynamics of the Ebola virus (EBOV); however, the information regarding EBOV sequences is insufficient, especially the clinical outcomes, given that the correlation between the clinical outcomes and the genetic evolution of EBOV is still not clear. Here, we collected and curated a comprehensive data set that includes 514 EBOV genome sequences from patients with confirmed EVD (including 60 sequences not previously studied), >87.5% of which have residence information and definitive clinical outcomes. Phylogenetic reconstruction revealed 11 lineages of EBOV in Sierra Leone. The median-joining haplotype network showed that haplotypes that are associated with lethal outcomes tend to contribute more to the spread of the EBOV in Sierra Leone than those with live outcomes...
In August 2014, the National Institute for Communicable Diseases (NICD) in South Africa establish... more In August 2014, the National Institute for Communicable Diseases (NICD) in South Africa established a modular high-biosafety field Ebola diagnostic laboratory (SA FEDL) near Freetown, Sierra Leone in response to the rapidly increasing number of Ebola virus disease (EVD) cases. The SA FEDL operated in the Western Area of Sierra Leone, which remained a "hotspot" of the EVD epidemic for months. The FEDL was the only diagnostic capacity available to respond to the overwhelming demand for rapid EVD laboratory diagnosis for several weeks in the initial stages of the EVD crisis in the capital of Sierra Leone. Furthermore, the NICD set out to establish local capacity amongst Sierra Leonean nationals in all aspects of the FEDL functions from the outset. This led to the successful hand-over of the FEDL to the Sierra Leone Ministry of Health and Sanitation in March 2015. Between 25 August 2014 and 22 June 2016, the laboratory tested 11,250 specimens mostly from the Western Urban and ...
Ebola virus emerged in West Africa in December 2013. The high population mobility and poor public... more Ebola virus emerged in West Africa in December 2013. The high population mobility and poor public health infrastructure in this region led to the development of the largest Ebola virus disease (EVD) outbreak to date. On September 26, 2014, China dispatched a Mobile Biosafety Level-3 Laboratory (MBSL-3 Lab) and a well-trained diagnostic team to Sierra Leone to assist in EVD diagnosis using quantitative real-time PCR, which allowed the diagnosis of suspected EVD cases in less than 4 hours from the time of sample receiving. This laboratory was composed of three container vehicles equipped with advanced ventilation system, communication system, electricity and gas supply system. We strictly applied multiple safety precautions to reduce exposure risks. Personnel, materials, water and air flow management were the key elements of the biosafety measures in the MBSL-3 Lab. Air samples were regularly collected from the MBSL-3 Lab, but no evidence of Ebola virus infectious aerosols was detecte...
We performed Ebola virus disease diagnosis and viral load estimation for Ebola cases in Sierra Le... more We performed Ebola virus disease diagnosis and viral load estimation for Ebola cases in Sierra Leone during the late stage of the 2014-2015 outbreak (January-March 2015) and analyzed antibody and cytokine levels and the viral genome sequences. Ebola virus disease was confirmed in 86 of 1001 (9.7%) patients, with an overall case fatality rate of 46.8%. Fatal cases exhibited significantly higher levels of viral loads, cytokines, and chemokines at late stages of infection versus early stage compared with survivors. The viruses converged in a new clade within sublineage 3.2.4, which had a significantly lower case fatality rate.
The 2013-2016 epidemic of Ebola virus disease in West Africa was of unprecedented magnitude, dura... more The 2013-2016 epidemic of Ebola virus disease in West Africa was of unprecedented magnitude, duration and impact. Extensive collaborative sequencing projects have produced a large collection of over 1600 Ebola virus genomes, representing over 5% of known cases, unmatched for any single human epidemic. In this comprehensive analysis of this entire dataset, we reconstruct in detail the history of migration, proliferation and decline of Ebola virus throughout the region. We test the association of geography, climate, administrative boundaries, demography and culture with viral movement among 56 administrative regions. Our results show that during the outbreak viral lineages moved according to a classic 'gravity' model, with more intense migration between larger and more proximate population centers. Notably, we find that despite a strong attenuation of international dispersal after border closures, localized cross-border transmission beforehand had already set the seeds for an ...
During the Ebola virus outbreak of 2013-2016, the Viral Special Pathogens Branch field laboratory... more During the Ebola virus outbreak of 2013-2016, the Viral Special Pathogens Branch field laboratory in Sierra Leone tested approximately 26 000 specimens between August 2014 and October 2015. Analysis of the B2M endogenous control Ct values showed its utility in monitoring specimen quality, comparing results with different specimen types, and interpretation of results. For live patients, blood is the most sensitive specimen type and oral swabs have little diagnostic utility. However, swabs are highly sensitive for diagnostic testing of corpses.
Ebola virus disease (EVD) is a severe viral illness caused by Ebola virus (EBOV). The 2013-2016 ... more Ebola virus disease (EVD) is a severe viral illness caused by Ebola virus (EBOV). The 2013-2016 EVD outbreak in West Africa is the largest recorded, with >11 000 deaths. Development of the ReEBOV Antigen Rapid Test (ReEBOV RDT) was expedited to provide a point-of-care test for suspected EVD cases. Recombinant EBOV viral protein 40 antigen was used to derive polyclonal antibodies for RDT and enzyme-linked immunosorbent assay development. ReEBOV RDT limits of detection (LOD), specificity, and interference were analytically validated on the basis of Food and Drug Administration (FDA) guidance. The ReEBOV RDT specificity estimate was 95% for donor serum panels and 97% for donor whole-blood specimens. The RDT demonstrated sensitivity to 3 species of Ebolavirus (Zaire ebolavirus, Sudan ebolavirus, and Bundibugyo ebolavirus) associated with human disease, with no cross-reactivity by pathogens associated with non-EBOV febrile illness, including malaria parasites. Interference testing ...
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 23, 2016
During 2014-2015, an outbreak of Ebola virus disease (EVD) swept across parts of West Africa. No... more During 2014-2015, an outbreak of Ebola virus disease (EVD) swept across parts of West Africa. No approved antiviral drugs are available for Ebola treatment currently. A retrospective clinical case series was performed for EVD patients in Sierra Leone-China Friendship Hospital. Confirmed EVD patients were sequentially enrolled and treated with either WHO recommended supportive therapy (control group) from October 10(th) to 30(th), or treated with WHO recommended therapy plus Favipiravir (T-705) from November 1(st) to 10(th), 2014. Survival and virological characteristics were observed for 85 patients in the control group and 39 in the T-705 treatment group. The overall survival rate in the T-705 treatment group was higher than that of control group (56.4%, 22/39 vs 35.3%, 30/85, P=0.027). Among the 35 patients who finished all designed endpoint observations, the survival rate in T-705 treatment group (64.8%, 11/17) was higher than that of control group (27.8%, 5/18). Furthermore, ...
During the mid-transmission period of the Ebola virus disease (EVD) outbreak in Sierra Leone, a 1... more During the mid-transmission period of the Ebola virus disease (EVD) outbreak in Sierra Leone, a 19-year-old pregnant woman, who was a petty trader in a health facility in Freetown, noticing no fetal movement for the past 3 days, reported to a health facility. Medical history and laboratory testing showed no abnormalities except that she was positive for sickle cell. She was not known to any surveillance team of having any epidemiological link to EVD case. She was induced with oral medications as well as IV infusion. EVD test showed that the fetus was positive to EVD with a high threshold value of 21, while the woman was negative for EVD with a threshold value of 42. The woman was positive to EVD IgG but negative to EVD IgM by ELISA technique. This is a rare EVD case in the period of medium transmission. We conclude that the woman may have come into contact with a low dose of virus not enough to cause a full blown EVD and that her immune system was able to stop the virus from further...
Background: The heterogeneity of the pre-antiretroviral (pre-ART) population calls for more granu... more Background: The heterogeneity of the pre-antiretroviral (pre-ART) population calls for more granular depictions of the cascade of HIV care. Methods: We studied a prospective cohort of persons newly diagnosed with HIV infection from a single center in Freetown, Sierra Leone, over a 12-month period and then traced those persons who were lost to follow-up (LTFU) during pre-ART care (before ART initiation). ART eligibility was based on a CD4 cell count result of < 350 mm/cells and/or WHO clinical stage 3 or 4. Persons who attended an appointment in the final three months were considered to be retained in care. Adherence to ART was measured using pharmacy refill dates. "Effective HIV care" was defined as completion of the cascade of care at 12-months regardless of whether patients are on ART. Tracing outcomes were obtained for those who were LTFU during pre-ART care. Results: 408 persons newly diagnosed with HIV infection were screened, 338 were enrolled, and 255 persons were staged for ART. ART-ineligible persons had higher retention rates than ART-eligible persons (59.6% vs 41.8%, p=0.03). 77 (22.8%) of 338 persons received effective HIV care. Most attrition (61.9%) occurred with persons during pre-ART care. 123 of 138 persons (89.1%) who were LTFU prior to ART initiation were found, and 91 of those 123 (74.0%) were alive. Of the 74 persons who were alive and described their engagement in care, 40 (54.1%) stopped care. Nearly half (42.5%) of those 40 stopped after assessment of ART-eligibility but before ART initiation. The main limitation of this study was the lack of tracing outcomes for those lost during ART care. Conclusions: The majority of the pre-ART LTFU population stopped their care, particularly after ART-eligibility but before ART initiation. Interventions to hasten ART initiation and retain this at-risk group may have significant downstream impact on effective HIV care
Background The 2014â 2016 Ebola virus epidemic in West Africa was the largest outbreak of Ebola v... more Background The 2014â 2016 Ebola virus epidemic in West Africa was the largest outbreak of Ebola virus disease (EVD) in history. Clarifying the influence of other prevalent diseases such as human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) will help improve treatment and supportive care of patients with EVD. Case presentation We examined HIV and hepatitis C virus (HCV) antibody prevalence among suspected EVD cases from the Sierra Leone-China Friendship Biological Safety Laboratory during the epidemic in Sierra Leone. HIV and HCV antibodies were tested in 678 EVD-negative samples by enzyme-linked immunosorbent assay. A high HIV prevalence (17.6%) and low HCV prevalence (0.22%) were observed among the suspected cases. Notably, we found decreased HIV positive rates among the suspected cases over the course of the epidemic. This suggests a potentially beneficial effect of an improved public health system after assistance from the World Health Organ...
OBJECTIVE People in Western Africa suffer greatly from febrile jaundice, which is caused by a var... more OBJECTIVE People in Western Africa suffer greatly from febrile jaundice, which is caused by a variety of pathogens. However, yellow fever virus (YFV) is the only pathogen under surveillance in Sierra Leone owing to the undeveloped medical and public health system there. Most of the results of YFV identification are negative. Elucidation of the pathogen spectrum is required to reduce the prevalence of febrile jaundice. METHODS In the present study, we used Ion Torrent semiconductor sequencing to profile the pathogen spectrum in archived YFV-negative sera from 96 patients in Sierra Leone who presented with unexplained febrile jaundice. RESULTS The most frequently identified sequencing reads belonged to the following pathogens: cytomegalovirus (89.58%), Epstein-Barr virus (55.21%), hepatitis C virus (34.38%), rhinovirus (28.13%), hepatitis A virus (20.83%), coxsackievirus (10.42%), Ebola virus (8.33%), hepatitis E virus (8.33%), lyssavirus (4.17%), leptospirosis (4.17%), chikungunya vi...
SAHARA J : journal of Social Aspects of HIV/AIDS Research Alliance, Dec 1, 2018
Evaluations of community-based antiretroviral therapy (ART) programmes have demonstrated positive... more Evaluations of community-based antiretroviral therapy (ART) programmes have demonstrated positive outcomes, but little is known about the impact of tapering community-based ART. The objective of this study was to assess 24-month HIV retention outcomes of a community-based ART programme and its tapered visit frequency in Koidu City, Sierra Leone. This retrospective, quasi-experimental study compared outcomes of 52 HIV-infected persons initiated on community-based ART against 91 HIV-infected persons receiving the standard of care from November 2009 to February 2013. The community-based ART pilot programme was designed to strengthen the standard of care through a comprehensive, patient-centred case management strategy. The strategy included medical, educational, psychological, social, and economic support. Starting in October 2011, the frequency of home visits was tapered from twice daily every day per week to once daily three days per week. Outcomes were retention in care at 12 and 24...
This study aimed to investigate the serological characteristics of Ebola virus (EBOV) infection d... more This study aimed to investigate the serological characteristics of Ebola virus (EBOV) infection during the late phase of the Ebola outbreak in Sierra Leone. In total, 877 blood samples from 694 suspected Ebola virus disease (EVD) cases assessed from March to December 2015, were analyzed via real-time reverse transcription polymerase chain reaction (RT-PCR) for viral RNA and enzyme-linked immunosorbent assay (ELISA) and Luminex to detect antibodies against EBOV. Viral load and EBOV-specific IgM/IgG titers displayed a declining trend during March to December 2015. Viral RNA load decreased rapidly at earlier stages after disease onset, while EBOV-specific IgM and IgG still persisted in 58.1% (18/31) and 93.5% (29/31) of the confirmed EVD patients and in 3.8% (25/663) and 17.8% (118/663) of the RNA-negative suspected patients in the later phase, respectively. Dynamic analysis of longitudinally collected samples from eight EVD patients revealed typically reversed trends of declining vira...
A serosurvey of anti-Ebola Zaire virus nucleoprotein IgG prevalence was carried out among Ebola v... more A serosurvey of anti-Ebola Zaire virus nucleoprotein IgG prevalence was carried out among Ebola virus disease survivors and their Community Contacts in Bombali District, Sierra Leone. Our data suggest that the specie of Ebola virus () responsible of the 2013-2016 epidemic in West Africa may cause mild or asymptomatic infection in a proportion of cases, possibly due to an efficient immune response.
Sierra Leone was the most severely affected country in Western Africa during the 2013-2016 outbre... more Sierra Leone was the most severely affected country in Western Africa during the 2013-2016 outbreak of Ebola virus disease (EVD). Previous genome surveillance studies have revealed the origin, diversity, and evolutionary dynamics of the Ebola virus (EBOV); however, the information regarding EBOV sequences is insufficient, especially the clinical outcomes, given that the correlation between the clinical outcomes and the genetic evolution of EBOV is still not clear. Here, we collected and curated a comprehensive data set that includes 514 EBOV genome sequences from patients with confirmed EVD (including 60 sequences not previously studied), >87.5% of which have residence information and definitive clinical outcomes. Phylogenetic reconstruction revealed 11 lineages of EBOV in Sierra Leone. The median-joining haplotype network showed that haplotypes that are associated with lethal outcomes tend to contribute more to the spread of the EBOV in Sierra Leone than those with live outcomes...
In August 2014, the National Institute for Communicable Diseases (NICD) in South Africa establish... more In August 2014, the National Institute for Communicable Diseases (NICD) in South Africa established a modular high-biosafety field Ebola diagnostic laboratory (SA FEDL) near Freetown, Sierra Leone in response to the rapidly increasing number of Ebola virus disease (EVD) cases. The SA FEDL operated in the Western Area of Sierra Leone, which remained a "hotspot" of the EVD epidemic for months. The FEDL was the only diagnostic capacity available to respond to the overwhelming demand for rapid EVD laboratory diagnosis for several weeks in the initial stages of the EVD crisis in the capital of Sierra Leone. Furthermore, the NICD set out to establish local capacity amongst Sierra Leonean nationals in all aspects of the FEDL functions from the outset. This led to the successful hand-over of the FEDL to the Sierra Leone Ministry of Health and Sanitation in March 2015. Between 25 August 2014 and 22 June 2016, the laboratory tested 11,250 specimens mostly from the Western Urban and ...
Ebola virus emerged in West Africa in December 2013. The high population mobility and poor public... more Ebola virus emerged in West Africa in December 2013. The high population mobility and poor public health infrastructure in this region led to the development of the largest Ebola virus disease (EVD) outbreak to date. On September 26, 2014, China dispatched a Mobile Biosafety Level-3 Laboratory (MBSL-3 Lab) and a well-trained diagnostic team to Sierra Leone to assist in EVD diagnosis using quantitative real-time PCR, which allowed the diagnosis of suspected EVD cases in less than 4 hours from the time of sample receiving. This laboratory was composed of three container vehicles equipped with advanced ventilation system, communication system, electricity and gas supply system. We strictly applied multiple safety precautions to reduce exposure risks. Personnel, materials, water and air flow management were the key elements of the biosafety measures in the MBSL-3 Lab. Air samples were regularly collected from the MBSL-3 Lab, but no evidence of Ebola virus infectious aerosols was detecte...
We performed Ebola virus disease diagnosis and viral load estimation for Ebola cases in Sierra Le... more We performed Ebola virus disease diagnosis and viral load estimation for Ebola cases in Sierra Leone during the late stage of the 2014-2015 outbreak (January-March 2015) and analyzed antibody and cytokine levels and the viral genome sequences. Ebola virus disease was confirmed in 86 of 1001 (9.7%) patients, with an overall case fatality rate of 46.8%. Fatal cases exhibited significantly higher levels of viral loads, cytokines, and chemokines at late stages of infection versus early stage compared with survivors. The viruses converged in a new clade within sublineage 3.2.4, which had a significantly lower case fatality rate.
The 2013-2016 epidemic of Ebola virus disease in West Africa was of unprecedented magnitude, dura... more The 2013-2016 epidemic of Ebola virus disease in West Africa was of unprecedented magnitude, duration and impact. Extensive collaborative sequencing projects have produced a large collection of over 1600 Ebola virus genomes, representing over 5% of known cases, unmatched for any single human epidemic. In this comprehensive analysis of this entire dataset, we reconstruct in detail the history of migration, proliferation and decline of Ebola virus throughout the region. We test the association of geography, climate, administrative boundaries, demography and culture with viral movement among 56 administrative regions. Our results show that during the outbreak viral lineages moved according to a classic 'gravity' model, with more intense migration between larger and more proximate population centers. Notably, we find that despite a strong attenuation of international dispersal after border closures, localized cross-border transmission beforehand had already set the seeds for an ...
During the Ebola virus outbreak of 2013-2016, the Viral Special Pathogens Branch field laboratory... more During the Ebola virus outbreak of 2013-2016, the Viral Special Pathogens Branch field laboratory in Sierra Leone tested approximately 26 000 specimens between August 2014 and October 2015. Analysis of the B2M endogenous control Ct values showed its utility in monitoring specimen quality, comparing results with different specimen types, and interpretation of results. For live patients, blood is the most sensitive specimen type and oral swabs have little diagnostic utility. However, swabs are highly sensitive for diagnostic testing of corpses.
Ebola virus disease (EVD) is a severe viral illness caused by Ebola virus (EBOV). The 2013-2016 ... more Ebola virus disease (EVD) is a severe viral illness caused by Ebola virus (EBOV). The 2013-2016 EVD outbreak in West Africa is the largest recorded, with >11 000 deaths. Development of the ReEBOV Antigen Rapid Test (ReEBOV RDT) was expedited to provide a point-of-care test for suspected EVD cases. Recombinant EBOV viral protein 40 antigen was used to derive polyclonal antibodies for RDT and enzyme-linked immunosorbent assay development. ReEBOV RDT limits of detection (LOD), specificity, and interference were analytically validated on the basis of Food and Drug Administration (FDA) guidance. The ReEBOV RDT specificity estimate was 95% for donor serum panels and 97% for donor whole-blood specimens. The RDT demonstrated sensitivity to 3 species of Ebolavirus (Zaire ebolavirus, Sudan ebolavirus, and Bundibugyo ebolavirus) associated with human disease, with no cross-reactivity by pathogens associated with non-EBOV febrile illness, including malaria parasites. Interference testing ...
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 23, 2016
During 2014-2015, an outbreak of Ebola virus disease (EVD) swept across parts of West Africa. No... more During 2014-2015, an outbreak of Ebola virus disease (EVD) swept across parts of West Africa. No approved antiviral drugs are available for Ebola treatment currently. A retrospective clinical case series was performed for EVD patients in Sierra Leone-China Friendship Hospital. Confirmed EVD patients were sequentially enrolled and treated with either WHO recommended supportive therapy (control group) from October 10(th) to 30(th), or treated with WHO recommended therapy plus Favipiravir (T-705) from November 1(st) to 10(th), 2014. Survival and virological characteristics were observed for 85 patients in the control group and 39 in the T-705 treatment group. The overall survival rate in the T-705 treatment group was higher than that of control group (56.4%, 22/39 vs 35.3%, 30/85, P=0.027). Among the 35 patients who finished all designed endpoint observations, the survival rate in T-705 treatment group (64.8%, 11/17) was higher than that of control group (27.8%, 5/18). Furthermore, ...
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Papers by Brima Kargbo