African Outbreak Research Articles

Unravelling the dispersal dynamics and ecological drivers of the African swine fever outbreak in Belgium

Abstract African swine fever is a devastating disease of domestic pigs and wild boars caused by African swine fever virus (ASFV). ASFV originates from sub‐Saharan African countries. In the last 10 years, the virus left its endemic range to spread to eastern Europe and Russia. On September 2018, Belgian authorities reported that ASFV had been detected in two wild boars in a southern area of the country. One year later, no domestic pig has been infected, with the last ASFV‐positive wild boar being confirmed in mid‐August 2019, suggesting that the outbreak is now controlled. However, the dispersal dynamics as well as the specific impact of ecological factors and intervention measures on the outbreak remain unknown. In total, 827 positive cases have been reported in wild boar populations. In this study, we exploit the resulting spatio‐temporal distribution of occurrence data to investigate the wavefront progression. We first present the application of recently developed methods to quantify the local wavefront velocity of an invading epidemic. Second, we develop and apply a novel analytical framework that uses occurrence data to investigate the impact of ecological factors on the dispersal dynamics of a wavefront progression. Our analyses highlighted that the network of barriers, involving installed fences, had an impact on both the effective dispersal and the wavefront dispersal velocity. Furthermore, we also demonstrated that the wavefront progression was slower outside forest areas. Together, these results have concrete implications for potential future ASFV epidemics in similar regions. Synthesis and applications. We describe a novel analytical approach that exploits occurrence data to investigate the impact of ecological factors on the wavefront velocity and actual wavefront progression. This methodology has the potential to be quickly applied to outbreak datasets solely made of occurrence data, with key benefits for the epidemiological investigations of external spatial factors impacting pathogen dispersal across non‐endemic areas. Our analytical workflow could also be further applied to investigate the impact of ecological factors on any kind of biological dispersions (pathogen spreads, invasive species).

Knowledge, attitude and practices of pig farmers post African swine fever outbreaks in Ogun and Oyo states of Nigeria

The experience during African swine fever (ASF) virus outbreak can be devastating. This study aimed to assess the knowledge, attitude and practise among pig farmers to avoiding resurgence of ASF outbreaks in Oyo and Ogun States of Nigeria where ASF outbreaks had been earlier reported. Non participatory observations and participatory interviews using pre-tested structured questionnaire were conducted in 2016 among 92 consenting pig farms post-ASF outbreak. The study showed that one in two of pig farms studied had suffered from ASF outbreak before. Meanwhile, several bio-security breaches that facilitate ASF and other infectious agents spread were still maintained including ‘farm restocking with ASF survivor pigs’ (61.5%; 32/52), ‘boar lending among farms for breeding purposes without examination’ (54.3%; 50/92), ‘extensive system and semi-intensive pig management’ (21.7%; 20/92), ‘farm attendants sharing among pig farms’ (19.6%; 18/92), ‘farm equipment/ implements/ facilities sharing among farms’ (22.8%; 21/92), selling of pig carcass (9.8%; 9/92), ‘carcass disposal in the bush’ (19.6%; 18/92). In this study we found out that management and bio-security activities in the pig farms studied were still poor and could place them at high risk of infection and repeated disease outbreaks in the future. The study suggests that pig farmers had not learnt from the previous ASF outbreaks. Therefore, proper sensitization on ASF epidemiology, public health significance and socioeconomic impact should be carried out. This study calls for swift action to prevent future calamities in pig production facilities in the study areas.
 Keywords: African swine fever, Biosecurity, Nigeria, Outbreak, Sensitization

Modelling the global economic consequences of a major African swine fever outbreak in China.

African swine fever is a deadly porcine disease that has spread into East Asia where it is having a detrimental effect on pork production. However, the implications of African swine fever on the global pork market are poorly explored. Two linked global economic models are used to explore the consequences of different scales of the epidemic on pork prices and on the prices of other food types and animal feeds. The models project global pork prices increasing by 17-85% and unmet demand driving price increases of other meats. This price rise reduces the quantity of pork demanded but also spurs production in other parts of the world, and imports make up half the Chinese losses. Demand for, and prices of, food types such as beef and poultry rise, while prices for maize and soybean used in feed decline. There is a slight decline in average per capita calorie availability in China, indicating the importance of assuring the dietary needs of low-income populations. Outside China, projections for calorie availability are mixed, reflecting the direct and indirect effects of the African swine fever epidemic on food and feed markets.

Re-emergence of Highly Pathogenic Avian Influenza H5N1 in Nigeria, 2014-2016: Role of Social Network and Value Chain Forces in Interstate Transmission.

Since 2004, high pathogenic avian influenza (HPAI) due to H5N1 virus among others has caused a major veterinary health crisis, resulting in the loss of millions of poultry through death or culling in several countries in Asia, the Middle East, Europe, Africa and North America (Alexander 2007; Lee et al. 2016). The first African outbreak was reported from Nigeria in 2006 in domestic poultry (Joannis et al. 2006) and persisted till 2008 (Fusaro et al. 2010). These outbreaks negatively affected animal and public health as well as the economy, and were caused by viruses belonging to genetic clades 2.2, 2.2.1, 2.2.2 and 2.3.2.1c (Aiki-Raji et al. 2008; Fusaro et al. 2010; Monne et al. 2015).

Drivers, Risk Factors and Dynamics of African Swine Fever Outbreaks, Southern Highlands, Tanzania.

African swine fever remains an important pig disease globally in view of its rapid spread, economic impacts and food implications, with no option of vaccination or treatment. The Southern Highlands zone of Tanzania, an important pig-producing hub in East Africa, is endemic with African swine fever (ASF). From approximately the year 2010, the recurrence of outbreaks has been observed and it has now become a predictable pattern. We conducted exploratory participatory epidemiology and participatory disease surveillance in the Southern Highlands to understand the pig sector and the drivers and facilitators of infections, risk factors and dynamics of ASF in this important pig-producing area. Pigs continue to play a major role in rural livelihoods in the Southern Highlands and pork is a major animal protein source. Outbreaks of diseases, particularly ASF, have continued to militate against the scaling up of pig operations in the Southern Highlands. Intra- and inter-district and trans-border transnational outbreaks of ASF, the most common disease in the Southern Highlands, continue to occur. Trade and marketing systems, management systems, and lack of biosecurity, as well as anthropogenic (human) issues, animals and fomites, were identified as risk factors and facilitators of ASF infection. Changes in human behavior and communication in trade and marketing systems in the value chain, biosecurity and pig management practices are warranted. Relevant training must be implemented alongside the launch of the national ASF control strategy for Tanzania, which already established a roadmap for combating ASF in Tanzania. The high-risk points (slaughter slabs, border areas, and farms with poor biosecurity) and high-risk period (November–March) along the pig value chain must be targeted as critical control points for interventions in order to reduce the burden of infection.

Ebola virus disease.

Ebola virus disease (EVD) is a severe and frequently lethal disease caused by Ebola virus (EBOV). EVD outbreaks typically start from a single case of probable zoonotic transmission, followed by human-to-human transmission via direct contact or contact with infected bodily fluids or contaminated fomites. EVD has a high case–fatality rate; it is characterized by fever, gastrointestinal signs and multiple organ dysfunction syndrome. Diagnosis requires a combination of case definition and laboratory tests, typically real-time reverse transcription PCR to detect viral RNA or rapid diagnostic tests based on immunoassays to detect EBOV antigens. Recent advances in medical countermeasure research resulted in the recent approval of an EBOV-targeted vaccine by European and US regulatory agencies. The results of a randomized clinical trial of investigational therapeutics for EVD demonstrated survival benefits from two monoclonal antibody products targeting the EBOV membrane glycoprotein. New observations emerging from the unprecedented 2013–2016 Western African EVD outbreak (the largest in history) and the ongoing EVD outbreak in the Democratic Republic of the Congo have substantially improved the understanding of EVD and viral persistence in survivors of EVD, resulting in new strategies toward prevention of infection and optimization of clinical management, acute illness outcomes and attendance to the clinical care needs of patients.

Characterization of SAT2 foot-and-mouth disease 2013/2014 outbreak viruses at the wildlife-livestock interface in South Africa.

The Southern African Territories (SAT)-type foot-and-mouth disease viruses (FMDV) are endemic to the greater Kruger National Park (KNP) area in South Africa, where they are maintained through persistent infections in African buffalo. The occurrence of FMDV within the Greater KNP area constitutes a continual threat to the livestock industry. To expand on knowledge of FMDV diversity, the genetic and antigenic relatedness of SAT2-type viruses isolated from cattle during a FMD outbreak in Mpumalanga Province in 2013 and 2014 were investigated. Cattle from twelve diptanks tested positive on polymerase chain reaction (PCR), and molecular epidemiological relationships of the viruses were determined by VP1 sequencing. Phylogenetic analysis of the SAT2 viruses from the FMD outbreak in Mpumalanga in 2013/2014 revealed their genetic relatedness to other SAT2 isolates from topotype I (South Africa, Zimbabwe and Mozambique), albeit genetically distinct from previous South African outbreak viruses (2011 and 2012) from the same topotype. The fifteen SAT2 field isolates clustered into a novel genotype with ≥98.7% nucleotide identity. High neutralization antibody titres were observed for four 2013/2014 outbreak viruses tested against the SAT2 reference antisera representative of viruses isolated from cattle and buffalo from South Africa (topotype I) and Zimbabwe (topotype II). Comparison of the antigenic relationship (r1 values) of the outbreak viruses with reference antisera indicated a good vaccine match with 90% of r1 values>0.3. The r1 values for the 2013/2014 outbreak viruses were 0.4 and above for the three South African vaccine/reference strains. These results confirm the presence of genetic and antigenic variability in SAT2 viruses and suggest the emergence of new variants at the wildlife-livestock interface in South Africa. Continuous characterization of field viruses should be performed to identify new virus strains as epidemiological surveillance to improve vaccination efforts.

Diversity of Diptera Species in Estonian Pig Farms.

In light of the African swine fever outbreaks in Estonian pig farms during the past few years, the question of the vector potential of Diptera in the pig farm environment has risen. However, the arthropod fauna of the pig farm environment is currently not well established. Hence, the aim of this study was to clarify the species diversity in pig farms. In total, 22 Diptera species or species groups were found in Estonian pig farms. There were altogether 186,701 individual arthropods collected, from which 96.6% (180,444) belonged to the order of true flies (Insecta: Diptera). The remaining 3.4% were from other insect orders, arachnids, or just damaged and unidentifiable specimens. The activity density and diversity of dipterans differed significantly between 12 sampled farms but not throughout the sampling period. The present study is amongst the few to provide a large-scale overview of pig-farm-associated Diptera in the temperate climate zone.

Investigation of African swine fever outbreaks in pigs outside the controlled areas of South Africa, 2012-2017.

South Africa historically experienced sporadic African swine fever (ASF) outbreaks in domestic pigs in the northern parts of the country. This was subsequently indicated to be because of spillover from the sylvatic cycle of ASF between warthog and tampans (soft ticks) in the area. South Africa declared this area an ASF-controlled area in 1935, and the area is still controlled in terms of the Animal Diseases Act, 1984 (Act 35 of 1984). Two main epidemics of ASF in domestic pigs were identified outside of the South African ASF-controlled area. The first occurred in 2012 with outbreaks in Gauteng and Mpumalanga provinces, and the second occurred in 2016–2017 with outbreaks in the North West, Free State and Northern Cape provinces. These were the first ASF epidemics in South Africa associated with transmission of the disease via a domestic cycle. This study found that the spread of ASF in these epidemics was mainly via auctions, swill feeding and scavenging. These three aspects need to be addressed in terms of awareness and education on the disease including implementation of biosecurity measures in order to prevent future ASF outbreaks in South Africa. Specific biosecurity measures should be implemented in the semi-commercial sector to prevent ASF-infected pigs and pig products from being moved to naïve pigs and therefore spreading the disease.

Potential to export fresh pork in the event of an African swine fever outbreak in the United States

An African swine fever (ASF) outbreak in the United States would result in the loss of fresh pork exports and a decrease in pig price. The World Organisation for Animal Health (OIE) Terrestrial Animal Health Code provides a potential opportunity for packers, working with swine production systems and the US Department of Agriculture (USDA), to maintain a significant portion of exports during an ASF outbreak through a combination of producer biosecurity and surveillance, packers only accepting pigs from production systems that meet specific requirements, and the USDA developing veterinary certificates for export stating the pork shipment meets the OIE requirements.

Development and Evaluation of a Duo Zaire ebolavirus Real-Time RT-PCR Assay Targeting Two Regions within the Genome.

Preparedness and response actions to mitigate Ebola virus disease (EVD) outbreaks rely on rapid diagnosis to be implemented locally to sort suspect patients attending health centers. Our aim was (i) to develop and evaluate an RT-qPCR assay combining primers and probes derived from two reference assays targeting different genomic regions; (ii) to study whether sensitivity and specificity of this dual-target assay were at least equal or better to the parental assays; (iii) to implement this dual-target assay onto the Cepheid GeneXpert open cartridge as a proof of principle for technological transfer aiming at bedsite testing locally. To do so, three home-made published RT-qPCR assays were selected to be compared with the RealStar® Filovirus Screen RT-PCR kit 1.0 (Altona Diagnostics, Hamburg, Germany), a technique that was largely deployed during the 2014–2015 West African EVD outbreak. Primers and probes sequences of the custom-made assays were analyzed in silico against a multiple sequence alignment, including >250 complete sequences corresponding to strains that have caused EVD epidemics in the past. Genomic RNA purified from the Mekambo strain of Zaire ebolavirus (EBOV) was used to study the sensitivity of the five methods. Based on these results, two in-house methods were selected and adapted to design the dual-target assay, which performances were compared to those of the parental assays using a synthetic RNA control. The dual-target assay showed better sensitivity and limit of detection (LoD95 at 0.4 copies/µL) than the parental methods (1.7 and 2.2 copies/µL). Ultimately, the dual-target assay was transferred onto the GeneXpert Flex-03 open cartridge, demonstrating a LoD95 at 0.75 copies/µL. Together these results indicate that EBOV dual-target assay has the potential to be used during EVD outbreak in the laboratory having performed molecular testing during the recent outbreaks.

Prediction for global African swine fever outbreaks based on a combination of random forest algorithms and meteorological data.

African swine fever (ASF) is a virulent infectious disease of pigs. As there is no effective vaccine and treatment method at present, it poses a great threat to the pig industry once it breaks out. In this paper, we used ASF outbreak data and the WorldClim database meteorological data and selected the CfsSubset Evaluator-Best First feature selection method combined with the random forest algorithms to construct an African swine fever outbreak prediction model. Subsequently, we also established a test set for data other than modelling, and the accuracy accuracy value range of the model on the independent test set was 76.02%-84.64%, which indicated that the modelling effect was better and the prediction accuracy was higher than previous estimates. In addition, logistic regression analysis was conducted on 12 features used for modelling and the ROC curves were drawn. The results showed that the bio14 features (precipitation of driest month) had the largest contribution to the outbreak of ASF, and it was speculated that the outbreak of the epidemic was significantly related to precipitation. Finally, we used this qualitative prediction model to build a global online prediction system for ASF outbreaks, in the hope that this study will help to decision-makers who can then take the relevant prevention and control measures in order to prevent the further spread of future epidemics of the disease.

Extensive recombination challenges the utility of Sugarcane mosaic virus phylogeny and strain typing

Sugarcane mosaic virus (SCMV) is distributed worldwide and infects three major crops: sugarcane, maize, and sorghum. The impact of SCMV is increased by its interaction with Maize chlorotic mottle virus which causes the synergistic maize disease maize lethal necrosis. Here, we characterised maize lethal necrosis-infected maize from multiple sites in East Africa, and found that SCMV was present in all thirty samples. This distribution pattern indicates that SCMV is a major partner virus in the East African maize lethal necrosis outbreak. Consistent with previous studies, our SCMV isolates were highly variable with several statistically supported recombination hot- and cold-spots across the SCMV genome. The recombination events generate conflicting phylogenetic signals from different fragments of the SCMV genome, so it is not appropriate to group SCMV genomes by simple similarity.

The socio-economic distribution of exposure to Ebola: Survey evidence from Liberia and Sierra Leone.

Socio-economic factors are widely believed to have been an important driver of the transmission of Ebola Virus Disease (EVD) during the West African outbreak of 2014–16, however, studies that have investigated the relationship between socio-economic status (SES) and EVD have found inconsistent results. Using nationally representative household survey data on whether respondents knew a close friend or family member with Ebola, we explore the SES determinants of EVD exposure along individual, household, and community lines in Liberia and Sierra Leone. While we find no overall association between household wealth and EVD exposure, we find that pooled data mask important differences observed within countries with higher wealth households more likely to have been exposed to EVD in Sierra Leone and the opposite relationship in Liberia. Finally, we also generally find a positive association between education and EVD exposure both at the individual and the community levels in the full sample. There is an urgent need to better understand these relationships to examine both why the outbreak spread and to help prepare for future outbreaks.

Investigating the Cellular Transcriptomic Response Induced by the Makona Variant of Ebola Virus in Differentiated THP-1 Cells.

Recent studies have shown that transcriptomic analysis of blood samples taken from patients with acute Ebola virus disease (EVD) during the 2013–2016 West African outbreak was suggestive that a severe inflammatory response took place in acutely ill patients. The significant knowledge gained from studying the Makona variant, a cause of the largest known EVD outbreak, may be applicable to other species of ebolavirus, and other variants of the Ebola virus (EBOV) species. To investigate the ability of Makona to initiate an inflammatory response in human macrophages and characterise the host response in a similar manner to previously characterised EBOV variants, the human monocytic cell line THP-1 was differentiated into macrophage-like cells and infected with Makona. RNA-Seq and quantitative proteomics were used to identify and quantify host mRNA and protein abundance during infection. Data from infection with Reston virus (RESTV) were used as comparators to investigate changes that may be specific to, or enhanced in, Makona infection in relation to a less pathogenic species of ebolavirus.. This study found demonstrable induction of the inflammatory response, and increase in the activation state of THP-1 macrophages infected with Makona. NFκB and inflammation-associated transcripts displayed significant changes in abundance, reflective of what was observed in human patients during the 2013–2016 EBOV outbreak in West Africa, and demonstrated that transcriptomic changes found in Makona-infected cells were similar to that observed in Reston virus infection and that have been described in previous studies of other variants of EBOV.

Generation and Characterization of a Mouse-Adapted Makona Variant of Ebola Virus.

Ebola virus (EBOV) is a zoonotic pathogen that poses a significant threat to public health, causing sporadic yet devastating outbreaks that have the potential to spread worldwide, as demonstrated during the 2013–2016 West African outbreak. Mouse models of infection are important tools for the development of therapeutics and vaccines. Exposure of immunocompetent mice to clinical isolates of EBOV is nonlethal; consequently, EBOV requires prior adaptation in mice to cause lethal disease. Until now, the only immunocompetent EBOV mouse model was based on the Mayinga variant, which was isolated in 1976. Here, we generated a novel mouse-adapted (MA)-EBOV based on the 2014 Makona isolate by inserting EBOV/Mayinga-MA mutations into the EBOV/Makona genome, followed by serial passaging of the rescued virus in suckling mice. The resulting EBOV/Makona-MA causes lethal disease in adult immunocompetent mice within 6 to 9 days and has a lethal dose (LD50) of 0.004 plaque forming units (PFU). Two additional mutations emerged after mouse-adaptation in the viral nucleoprotein (NP) and membrane-associated protein VP24. Using reverse genetics, we found the VP24 mutation to be critical for EBOV/Makona-MA virulence. EBOV/Makona-MA infected mice that presented with viremia, high viral burden in organs, increased release of pro-inflammatory cytokines/chemokines, and lymphopenia. Our mouse model will help advance pre-clinical development of countermeasures against contemporary EBOV variants.

Vector Competence of Italian Populations of Culicoides for Some Bluetongue Virus Strains Responsible for Recent Northern African and European Outbreaks.

The distribution of Bluetongue virus (BTV) in Europe can be represented by two distinct and interconnected epidemiological systems (episystems), each characterized by different ecological characteristics and vector species. This study investigated the vector competence of Italian populations of Culicoides imicola and Culicoides obsoletus/scoticus to some representative BTV strains after artificial oral infection. The BTV strains were selected according to their ability to spread to one or both episystems and included BTV-4 ITA, responsible of the recent Italian and French BTV-4 outbreaks; the BTV-2 strain which caused the first BTV incursion in Italy, Corsica, and Balearic Islands; BTV-4 MOR, responsible for the epidemic in Morocco; and BTV-8, the strain which spread through Europe between 2006 and 2008. Blood-soaked cotton pledgets and Hemotek membrane feeder using Parafilm® membrane were used to artificially feed midges. For each population/strain, recovery rates (positive/tested heads) were evaluated using serogroup- and serotype-specific RT-PCR. The trial demonstrated that, except for the Abruzzo population of C. obsoletus/C. scoticus, which was refractory to BTV-4 MOR infection, all the investigated Culicoides populations are susceptible to the selected BTV strains and that, if prompt vaccination programs and restriction measures had not been implemented, BTV-2 and BTV-4 MOR could have spread all over Europe.

Vitamin A Supplementation Was Associated with Reduced Mortality in Patients with Ebola Virus Disease during the West African Outbreak

BackgroundMicronutrient supplementation is recommended in Ebola virus disease (EVD); however, there are limited data on therapeutic impacts of specific micronutrients. ObjectiveTo evaluate the association between vitamin A supplementation and mortality in EVD. MethodsThis retrospective cohort included patients with EVD admitted to 5 International Medical Corps Ebola Treatment Units (ETUs) in 2 countries during 2014–2015. Protocolized treatments with micronutrients were used at all ETUs: however, because of resource constraints, only a subset of patients received vitamin A. Standardized data on demographics, clinical characteristics, malaria status, and Ebola viral loads (cycle threshold values) were collected. The outcome of interest was mortality between cases treated with 200,000 IU of vitamin A on care days 1 and/or 2, and those not. Propensity scores based on the first 48 h of care were derived using covariates of age, ETU duration, malaria status, cycle threshold values, and clinical symptoms. Patients were matched 1:1 using nearest neighbors with replacement. Mortality between cases treated and not treated with vitamin A was compared using generalized estimating equations to calculate RR with associated 95% CI. ResultsThere were 424 cases analyzed, of which 330 (77.8%) were treated with vitamin A. The mean age was 30.5 y and 40.3% were men. The most common symptoms were diarrhea (85.6%), anorexia (80.7%), and abdominal pain (76.9%). Mortality proportions among cases treated and not treated with vitamin A were 55.0% and 71.9%, respectively. In the propensity-matched analysis, mortality was significantly lower among cases receiving vitamin A (RR = 0.77, 95% CI: 0.59, 0.99; P = 0.041). In a subgroup analysis of patients treated with multivitamins already containing vitamin A, additional vitamin A supplementation did not impact mortality. ConclusionsEarly vitamin A supplementation was associated with reduced mortality in patients with EVD, and should be further studied and considered for use in future epidemics.

Update of the species checklist of Culicoides Latreille, 1809 biting midges (Diptera: Ceratopogonidae) of Morocco

BackgroundInvestigations of Culicoides fauna, including inventories, were carried out in Morocco at different periods after the country had faced major bluetongue and African horse sickness outbreaks. However, no comprehensive reference publication has provided a clear overview of the Culicoides species diversity. This study reviewed available data on Culicoides biting midge species in Morocco from 1968 to 2015 (published and grey literature in French and English) in order to revise the current checklist, in light of state of the art taxonomic and systematic knowledge, and confirmed the checklist with morphological and molecular identifications of specimens collected from the region of Rabat.MethodsLiterature related to Culicoides collections in Morocco was collated. Authors were contacted to obtain raw data and additional information for the collections. Fresh Culicoides material was collected and examined from two sites around Rabat, the capital of Morocco. Each collected individual was examined and morphologically identified, if possible, to the species level. In addition, molecular identification was performed to separate closely related species, to confirm difficult morphological identifications and to confirm new species records.ResultsA total of 6121 individuals of Culicoides spp. were collected and analyzed and at least 17 species were identified: C. cataneii/C. gejgelensis, C. circumscriptus, C. fagineus, C. festivipennis, C. imicola, C. jumineri, C. kingi, C. longipennis, C. montanus, C. newsteadi, C. obsoletus, C. paolae, C. parotti, C. puncticollis, C. sahariensis, C. scoticus and C. subfagineus. Seven species were confirmed using phylogenetic analyses. Two new species records for Morocco are reported: C. paolae and C. subfagineus.ConclusionsThe Moroccan fauna of Culicoides now includes 54 valid species. Further work would certainly increase this total, as one of the clades we identified was not affiliated to any described and valid species.

Effect of an Intervention Package and Teamwork Training to Prevent Healthcare Personnel Self-contamination During Personal Protective Equipment Doffing.

BackgroundMore than 28 000 people were infected with Ebola virus during the 2014–2015 West African outbreak, resulting in more than 11 000 deaths. Better methods are needed to reduce the risk of self-contamination while doffing personal protective equipment (PPE) to prevent pathogen transmission.MethodsA set of interventions based on previously identified failure modes was designed to mitigate the risk of self- contamination during PPE doffing. These interventions were tested in a randomized controlled trial of 48 participants with no prior experience doffing enhanced PPE. Contamination was simulated using a fluorescent tracer slurry and fluorescent polystyrene latex spheres (PLSs). Self-contamination of scrubs and skin was measured using ultraviolet light visualization and swabbing followed by microscopy, respectively. Doffing sessions were videotaped and reviewed to score standardized teamwork behaviors.ResultsParticipants in the intervention group contaminated significantly fewer body sites than those in the control group (median [interquartile range], 6 [3–8] vs 11 [6–13], P = .002). The median contamination score was lower for the intervention group than the control group when measured by ultraviolet light visualization (23.15 vs 64.45, P = .004) and PLS swabbing (72.4 vs 144.8, P = .001). The mean teamwork score was greater in the intervention group (42.2 vs 27.5, P < .001).ConclusionsAn intervention package addressing the PPE doffing task, tools, environment, and teamwork skills significantly reduced the amount of self-contamination by study participants. These elements can be incorporated into PPE guidance and training to reduce the risk of pathogen transmission.