Air pollution and climate change are intricately linked, each amplifying the other's effects. Both have an impact on respiratory conditions such as asthma, chronic obstructive pulmonary disease, and allergy, most commonly associated with exacerbations of these conditions. They also impact on the occurrence, etiology, and severity, including mortality, of respiratory infections, in particular pneumonia, especially among vulnerable populations. Commonly affected pathogens are many and include bacteria, viruses, and fungi. Ongoing research needs to determine fully the mechanisms and consequences of these environmental changes to understand how best to mitigate against these effects.

Background & aims: Various factors may cause significant daily variations in energy expenditure in and between critically patients. This nested, prospective study (ClinicalTrials.gov Identifier: NCT04099108) in a predominantly trauma surgical ICU, aimed to determine the course of measured energy expenditure over the first 10 days of critical illness, and to identify factors contributing to energy expenditure. Methods: Indirect calorimetry was performed on alternate days from ICU Day 3 +/- 1 until Day 10 +/- 1. The mean daily measured energy expenditure, respiratory quotient and total energy delivery as a percentage of measured energy expenditure were modelled using linear mixed regression with two fractional polynomial terms to accommodate non-linear responses over time. Results: Fifty ICU patients (mean age 36.9 +/- 11.8 years, Acute Physiology and Chronic Health Evaluation (APACHE II) 13.5 +/- 6.6, Sequential Organ Failure Assessment (SOFA) 4.5 +/- 3.2) were included. Mean body mass index (BMI) was 24.8 +/- 4.0 kg/m2 and mean ventilation duration 7.7 +/- 2.7 days. Mean daily measured energy expenditure showed a significant non-linear response (p = 0.006) increasing over the first 4 days peaking on day 5 and then plateauing. Mean daily respiratory quotient increased over the first 7 days, thereafter plateauing with a slight downward trend from day 8 despite a progressive increase in total energy delivery as a percentage of measured energy expenditure. Mean daily measured energy expenditure was significantly lower in the early than in the late acute phases (p = 0.024), whereas the late- and post-acute phases were similar. Age, sex and BMI significantly influenced measured energy expenditure. Conclusion: Measured energy expenditure showed a significant non-linear response over the first 10 days in ICU, increasing over the first 4 days peaking on day 5 then plateauing. The observed variability highlights the complexity of managing critically ill patients and the importance of personalised nutrition therapy. Additionally, the observed trend with a peak in measured energy expenditure around day five could inform timing and strategies for nutritional intervention in this patient cohort. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of European Society for Clinical Nutrition and Metabolism. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/li censes/by-nc-nd/4.0/).

BACKGROUND:Muscle wasting is a hallmark of critical illness. We evaluated the effect of amino acid supplementation and mobilization on early muscle loss in critically ill patients. METHODS:We conducted a randomized parallel-group trial involving adult patients admitted to the surgical intensive care unit of a tertiary hospital. Participants were randomly assigned to two groups, both receiving standard care nutrition and mobilization. The intervention group also received a daily intravenous amino acid bolus with 45 min of cycle ergometry, starting on days 3-4 for a mean of 6 days. The primary co-outcomes were changes in vastus lateralis myofiber cross-sectional area (from biopsies) and ultrasound-derived rectus femoris cross-sectional area, measured between the preintervention (day 2) and postintervention (day 8) time points. Analyses were conducted using mixed-model analysis of variance and least significant difference testing. Secondary outcomes included the protein-to-DNA ratio, muscle echogenicity, whole-body phase angle, muscle strength (Medical Research Council sum score) and physical capability (6-min walk test). RESULTS:Fifty patients (90% male, age 37 ± 12 years) were included. Standard of care participants received 1.23 ± 0.18 g/kg/day protein; intervention participants 1.57 ± 0.27 g/kg/day, including 0.37 ± 0.05 g/kg/day from the supplement. Muscle loss occurred significantly over time (biopsy P = 0.01; ultrasound P < 0.001), with no significant differences between groups. Similarly, no significant differences were observed in protein-to-DNA ratio, muscle echogenicity, phase angle, muscle strength, or physical capability. CONCLUSION:A short-duration combined intervention of intravenous bolus amino acids and cycle ergometry, limited to the acute phase of critical illness, did not reduce muscle loss or improve muscle quality, strength, or physical capability.

Background:There are few studies of long coronavirus disease (COVID) in low- and middle-income countries. Objectives:This study investigated long-term pulmonary manifestations of long COVID among adults in Johannesburg, South Africa. Method:This was a respiratory sub-study of a larger long COVID investigation. Cases with self-reported long COVID symptoms were recruited into four cohorts: prior asymptomatic infection, mild to moderate infection, hospitalised for severe infection and vaccinated prior to infection. Cases with respiratory comorbidity and/or well-characterised exposure to certain conditions (e.g. cigarette smoking) were excluded. Demographics, clinical features, spirometry, six-minute walk test (6MWT) and high-resolution computerised tomographic (HRCT) scan of the chest were recorded. Results:Of the 171 patients interviewed from the initial study, 36 with appropriate inclusion criteria were recruited a median of 2.1 years following their acute COVID-19 illness. Accordingly, the incidence of long COVID was 21.1% (36/171 patients) for the group as a whole and 5.9% (3/51), 25.0% (14/56), 37.8% (17/45) and 10.5% (2/19) for cohorts 1-4, respectively (p = 0.001). The major symptoms were tiredness and/or fatigue, shortness of breath and cough. Overall, 33 patients had abnormal 6MWT results, and 10 had abnormalities on spirometry; obstructive pattern in five, restrictive in three and mixed in two. Seven patients (six of whom were previously hospitalised) had probable/possible abnormalities compatible with long COVID on HRCT scan (p = 0.045). Conclusion:This study documented respiratory abnormalities in patients as long as 2 years after prior SARS-CoV-2 infection, especially among those with severe prior infection. Contribution:This was among the first studies comprehensively documenting pulmonary abnormalities in patients with long COVID in South Africa.

Background/Objectives: Pseudomonas aeruginosa (Psa) can circumvent antimicrobial chemotherapy, an ability enhanced by cigarette smoking (CS). This study probed potential benefits of combinations of anti-pseudomonal agents, and potential augmentation by a macrolide, in the absence or presence of cigarette smoke condensate (CSC). Methods: Two susceptible (WT: wild-type and DS: drug-sensitive) and one multidrug-resistant (MDR) strains of Psa were treated with amikacin, cefepime, and ciprofloxacin, individually and in combination, and with and without clarithromycin, followed by the measurement of planktonic growth and biofilm formation by spectrophotometry. Antibiotic interactions were determined using the fractional inhibitory concentration index (FICI) method. Effects on preformed biofilm density were measured following the addition of antibiotics: all procedures were performed in the absence and presence of CSC. Results: The minimal inhibitory concentrations (MICs) of the three agents ranged from 0.125 mg/L to 1 mg/L (WT and DS strains) and 16 mg/L to 64 mg/L (MDR strain), with all resistant to clarithromycin (125 mg/L). MIC values closely correlated with the antibiotic concentrations required to inhibit biofilm formation. FICI revealed synergism between most combinations, with augmentation by clarithromycin. Amikacin had the greatest effect on biofilm density, which was potentiated by combination with the other antibiotics, particularly clarithromycin. Exposure to CSC had variable, albeit modest, effects on bacterial growth and biofilm formation, but low concentrations increased biofilm mass and attenuated synergistic antimicrobial interactions and effects on biofilm density. Conclusions: Amikacin, cefepime, and ciprofloxacin, especially with clarithromycin, exhibit synergistic anti-pseudomonal activity and decrease preformed biofilm density. CSC attenuated these effects, illustrating the pro-infective potential of CS.

Purpose: There is a paucity of data from sub-Saharan Africa describing Severe Community Acquired Pneumonia (SCAP), a condition with significant morbidity and mortality. Materials and methods: This was a retrospective, single-centre, observational study of consecutive patients with SCAP admitted to the ICU at Charlotte Maxeke Johannesburg Academic Hospital, in South Africa between 1 July 2007 and 31 May 2019. Pneumonia was categorised as community-acquired if there had been no hospitalization in the preceding 2 weeks. Results: We identified 931 patients, (median age 37 [IQR 30-48] years), with the predominant co-morbidity being HIV co-infection (77.1 %). The median CURB-65 and APACHE II scores were 3 (IQR 2-3) and 18 (IQR 14-23) respectively, and most patients had multilobar consolidation on chest X-ray. Mycobacterium tuberculosis was the most common aetiology, followed by Streptococcus pneumoniae. The latter, and Pneumocystis jirovecii were more common amongst survivors and non-survivors, respectively. ICU mortality was 50.1 % and 85 % of patients required ventilation, mostly invasive mechanical ventilation. Ventilated patients and those requiring inotropic support and/or dialysis were more likely to die. Conclusion: We have described a cohort of patients with SCAP, with a comprehensive overview of all putative microbiological causes, which to our knowledge, is the largest reported in the literature.

SUMMARY Infections due to Acinetobacter spp. are among the most difficult to treat. Most are resistant to standard antibiotics, and there is difficulty in distinguishing colonizers from pathogens. This mini-review examines the available antibiotics that exhibit activity against these organisms and provides guidance as to which cultures are relevant and how to treat active infections. Antibiograms describing resistance mechanisms and the minimum inhibitory concentration (MIC) are essential to determine which agent or combination of agents should be used after confirmation of infection, utilizing clinical parameters and biomarkers such as procalcitonin. Directed therapy should be prompt as despite its reputation as a colonizer, the attributable mortality is high. However, although combination therapy is advised, no specific combination has definite evidence of superiority.

People living with HIV comprise a substantial number of the patients admitted to intensive care. This number varies according to geography, but all areas of the world are affected. In lower-income and middle-income countries, the majority of intensive care unit (ICU) admissions relate to infections, whereas in high-income countries, they often involve HIV-associated non-communicable diseases diagnoses. Management of infections potentially resulting in admission to the ICU in people living with HIV include sepsis, respiratory infections, COVID-19, cytomegalovirus infection, and CNS infections, both opportunistic and non-opportunistic. It is crucial to know which antiretroviral therapy (ART) is appropriate, when is the correct time to administer it, and to be aware of any safety concerns and potential drug interactions with ART. Although ART is necessary for controlling HIV infections, it can also cause difficulties relevant to the ICU such as immune reconstitution inflammatory syndrome, and issues associated with ART administration in patients with gastrointestinal dysfunction on mechanical ventilation. Managing infection in people with HIV in the ICU is complex, requiring collaboration from a multidisciplinary team knowledgeable in both the management of the specific infection and the use of ART. This team should include intensivists, infectious disease specialists, pharmacists, and microbiologists to ensure optimal outcomes for patients.

PurposeLimitations of life sustaining therapies (LLST) are frequent in intensive care units (ICUs), but no previous studies have examined end-of-life (EOL) care and LLST in South Africa (SA).Materials and methodsThis study evaluated LLST in SA from the data of a prospective, international, multicentre, observational study (Ethicus-2) and compared practices with countries in the rest of the world.ResultsLLST was relatively common in SA, and withholding was more frequent than withdrawing therapy. However, withdrawing and withholding therapy were less common, while failed CPR was more common, than in many other countries. No patients had an advance directive. Primary reasons for LLST in SA were poor quality of life, multisystem organ failure and patients' unresponsiveness to maximal therapy. Primary considerations for EOL decision-making were good medical practice and patients' best-interest, with the need for an ICU bed only rarely considered.ConclusionsWithholding was more common than withdrawing treatment both in SA and worldwide, although both were significantly less frequent in SA compared with the world average.

Objectives: Monitoring muscle mass (cross-sectional area [CSA]) and quality (echogenicity) using ultrasound may help optimise nutrition support in the critically ill. However, to date, ultrasound imaging has not been included in the undergraduate training of dietitians, who are mostly responsible for the nutrition care of critically ill patients. This study assessed the accuracy and reliability of bedside imaging performed by a dietitian trained according to standardised methodology, followed by blinded analyses. Methods: Two operators (a trainer and dietitian trainee) performed B-mode ultrasonography of the rectus femoris quadriceps muscle. For inter-rater accuracy, imaging was performed independently on 32 subjects by both operators, and for intra-rater reliability both obtained a second image on 15 subjects. A blinded assessor performed analyses (CSA and echogenicity) on all images. In a subset of 11 subjects, a musculoskeletal sonographer repeated all measurements. Inter- and intra-rater reliability were determined by calculating intraclass correlation coefficients (ICC), based on an absolute-agreement, 2-way mixed-effects model. An ICC > 0.75 was classified as good and > 0.90 as excellent. Results: Intra- (ICC = 0.9-0.94) and inter-rater (ICC = 0.85-0.95) reliability of the imaging performed was good to excellent. No statistically significant differences were found between the two operators (mean difference for CSA = 0.18 cm2, 95% CI = -0.38-0.03, p = 0.08; mean difference for echogenicity = 6.88, CI = -0.71-14.78, p = 0.07). Inter-rater reliability for image analyses was excellent (ICC = 0.97-1.0). Conclusion: Bedside ultrasound performed by a dietitian trained according to standardised methodology shows good to excellent reliability and reproducibility. Training dietitians to perform bedside ultrasound may help to monitor muscle mass and quality in the critically ill.

Objectives: There is a high incidence of lung diseases but very little data in South Africa relating to bronchoscopy practice. The objectives of the study are to determine the diagnostic yield, indications, and complications as well as determine the effectiveness of biopsy and bronchoalveolar lavage (BAL) in making diagnoses of infectious and non-infectious diseases. Materials and Methods: Six hundred and ninety-two patients were identified and 647 cases were analyzed due to 45 cases with inadequate data for analyses. A single-center retrospective cross-sectional review of patients who underwent bronchoscopy between January 2015 and December 2019 was conducted at the Charlotte Maxeke Johannesburg Academic Hospital. Results: The epidemiology of the subjects showed a significant male predominance (64.14%), with a mean age of 55.9 years of age. The most common indication was suspected malignancy, followed by non-resolving pneumonia, 63.99%, and 14.53%, respectively. A total of 120 (18.55%) patients were diagnosed with a malignancy on biopsy and 83 (12.83%) on BAL. Of all bronchoscopies performed, 85.94% had no complications during or after bronchoscopy, whereas 10.97% were complicated with bleeding. Conclusion: This audit revealed that flexible bronchoscopy is safe and effective and associated with minimal risk. This study revealed the use of bronchoscopy in diagnosing lung malignancies/carcinomas and highlights the necessity of the availability of bronchoscopy.

Background: Allergic rhinitis (AR) has a significant impact on the community as a whole with regard to quality of life and its relationship to allergic multi-morbidities. Appropriate diagnosis, treatment and review of the efficacy of interventions can ameliorate these effects. Yet, the importance of AR is often overlooked, and appropriate therapy is neglected. The availability of effective medications and knowledge as to management are often lacking in both public and private health systems. Methods: This review is based on a comprehensive literature search and detailed discussions by the South African Allergic Rhinitis Working Group (SAARWG). Results: The working group provided up-to-date recommendations on the epidemiology, pathology, diagnosis and management of AR, appropriate to the South African setting. Conclusion: Allergic rhinitis causes significant, often unappreciated, morbidity. It is a complex disease related to an inflammatory response to environmental allergens. Therapy involves education, evaluation of allergen sensitisation, pharmacological treatment, allergen immunotherapy (AIT) and evaluation of the success of interventions. Regular use of saline; the important role of intranasal corticosteroids, including those combined with topical antihistamines and reduction in the use of systemic steroids are key. Practitioners should have a thorough knowledge of associated morbidities and the need for specialist referral. Contribution: This review summarises the latest developments in the diagnosis and management of AR such that it is a resource that allows easy access for family practitioners and specialists alike.

Objectives: Nutritional support is a fundamental component of holistic patient care in the intensive care unit (ICU). There is a paucity of local data pertaining to nutritional support practices at ICUs in South Africa. The aim of this study was to determine nutritional support practices at an academic hospital ICU in Johannesburg, South Africa.Methods: In this cross-sectional, descriptive and retrospective study, a simple random sampling method was utilised to select 50 data collection days from a three-month period (1 August–31 October 2018). Data relevant to the study were extracted from the ICU charts of patients who received formulae-based enteral and/or parenteral nutrition on the selected days. Charts were categorised into acute phase days (≤ 72 hours from ICU admission) and recovery phase days (> 72 hours from ICU admission).Results: A total of 387 ICU charts were included in the final sample, comprising 114 acute phase and 273 recovery phase days. Overall, enteral nutrition was prescribed on 296 (76.5%) chart days while parenteral nutrition was prescribed on 111 (28.7%) chart days. The median daily fluid balance was approximately 600 ml positive. Target protein and calorie intake was achieved on 67 (17.3%) and 110 (28.4%) chart days respectively.Conclusion: Although protein and calorie intake was suboptimal in comparison with the recommended targets, it is in keeping with general international trends. Regular audits, training of staff, attention to minimising feeding interruptions and encouraging the timely initiation of enteral nutrition are recommended interventions that may be useful in achieving nutritional targets.

Background Chest radiographs are a common diagnostic tool in the internal medicine department, and correct interpretation is imperative for adequate patient management. Objectives To determine the diagnostic accuracy of common pathologies in South Africa that are evident on chest radiographs, and to determine whether there are discrepancies according to different levels of qualification of doctors rotating through the internal medicine department, and which factors contribute to an accurate diagnosis. Methods Fifteen chest radiographs with common pathologies were given to all doctors rotating through the Department of Internal Medicine at Chris Hani Baragwanath Academic Hospital, and they were asked to interpret them. Information pertaining to their experience, designation and confidence in chest radiograph interpretation was also obtained. Results Diagnostic accuracy according to years of experience was as follows: 0 - 5 years 27.0%, 6 - 10 years 43.0%, and >10 years 47.9%. For different designations, accuracy was as follows: consultants 50.5%, registrars 40.9%, medical officers 36.4%, and interns 19.5%. Participants who were confident obtained a mean score of 39.4% and those who were not, a mean score of 31.6%. Conclusion Chest radiographs are readily accessible and used daily in clinical practice in numerous facilities. An accurate diagnosis is important to provide quality healthcare. Improved training in interpretation for all, but especially for junior doctors, should be a priority in our training facilities. Study synopsis What the study adds. This study tested the diagnostic accuracy with regard to common pathologies present on chest X ray by doctors rotating through, or stationed at the internal medicine department at an academic hospital. Implications of the findings. Interpretation of chest X-rays was generally poor but the study did find that this improves with experience and confidence in diagnostic ability. These findings are significant in that they indicate a need to implement improved teaching programs in radiological interpretation, especially at an undergraduate level.

This paper discusses mechanisms of hypoxemia and interventions to oxygenate critically ill patients with COVID-19 which range from nasal cannula to noninvasive and mechanical ventilation. Noninvasive ventilation includes continuous positive airway pressure ventilation (CPAP) and high-flow nasal cannula (HFNC) with or without proning. The evidence for each of these modalities is discussed and thereafter, when to transition to mechanical ventilation (MV). Various techniques of MV, again with and without proning, and rescue strategies which would include extra corporeal membrane oxygenation (ECMO) when it is available and permissive hypoxemia where it is not, are discussed.

Ebola virus disease (EVD) caused by Ebola virus species Zaire ebolavirus (EBOV) is a major global health challenge causing sporadic outbreaks with high mortality. The minimum incubation period of EBOV, or the time from infection with the virus to the development of first symptoms, is thought to be 2 days and was initially established during the first EVD investigation in 1976.1WHOEbola virus disease.https://www.who.int/news-room/fact-sheets/detail/ebola-virus-diseaseDate accessed: July 24, 2023Google Scholar A published observation from the investigation noted that, “in one case of the disease, the only possible source of infection was contact with a probable case 48 hours before the latter developed symptoms”, and this observation was restated in another publication.2Breman JG Piot P Johnson K Pattyn S The epidemiology of Ebola hemorrhagic fever in Zaire, 1976.in: Pattyn SR Ebola virus haemorrhagic fever. Elsevier, New York, NY1978: 103-124Google Scholar, 3Burke J Declerq R Ghysebrechts G et al.Ebola hemorrhagic fever in Zaire, 1976: report of an international commission.Bull World Health Organ. 1978; 56: 271-293PubMed Google Scholar However, concluding that the minimum incubation period for EBOV is 2 days based on these reports is flawed for several reasons. First, the presumed source of the infection was a probable case of EVD and was not laboratory-confirmed; it is therefore uncertain whether the source truly had EVD. Second, since the report describes the contact between the source and the case occurring before the source developed symptoms, this implies asymptomatic transmission, which has been established to not occur with EBOV.4Dowell SF Mukunu R Ksiazek TG Khan AS Rollin PE Peters CJ Transmission of Ebola hemorrhagic fever: a study of risk factors in family members, Kikwit, Democratic Republic of the Congo, 1995. Commission de Lutte contre les Epidémies à Kikwit.J Infect Dis. 1999; 179: S87-S91Crossref PubMed Scopus (305) Google Scholar, 5Dean NE Halloran ME Yang Y Longini IM Transmissibility and pathogenicity of Ebola virus: a systematic review and meta-analysis of household secondary attack rate and asymptomatic infection.Clin Infect Dis. 2016; 62: 1277-1286Crossref PubMed Scopus (62) Google Scholar, 6US Centers for Disease Control and PreventionEbola disease: transmission.https://www.cdc.gov/vhf/ebola/transmission/index.htmlDate accessed: July 24, 2023Google Scholar Finally, the report's description of 48 h refers to the time between the case's contact with the alleged source and the source's onset of symptoms, which is itself not an incubation period. Two 2015 systematic reviews of the EBOV incubation period found insufficient data to support 2 days as the minimum incubation period of EBOV.7Velásquez GE Aibana O Ling EJ Diakite I Mooring EQ Murray MB Time from infection to disease and infectiousness for Ebola virus disease, a systematic review.Clin Infect Dis. 2015; 61: 1135-1140Crossref PubMed Scopus (30) Google Scholar, 8Van Kerkhove MD Bento AI Mills HL Ferguson NM Donnelly CA A review of epidemiological parameters from Ebola outbreaks to inform early public health decision-making.Sci Data. 2015; 2150019Crossref PubMed Scopus (89) Google Scholar We performed a literature review in PubMed to search for individual instances where both the dates of symptom onset and exposure were established, and where exposure was limited to either 1 day or a short range. We identified eight publications containing data on nine such cases (appendix p 7). Three (33%) of nine individuals were exposed via percutaneous introduction of the virus (eg, needlestick or laceration), five (56%) were exposed through a non-percutaneous route, and for one (11%) individual the route of exposure was unable to be determined (but was likely percutaneous). For some individuals with non-percutaneous exposure, the precise date of contact might have been approximate, and thus minimum incubation periods are estimated or include a range. In total, three of the nine individuals died (two with either known or plausible percutaneous exposure, and one with no percutaneous exposure). The minimum incubation period for these nine instances of EBOV transmission ranged from 4–13 days. No cases reported a minimum incubation period of 2 days. In the case of the individual with plausible percutaneous exposure, the incubation period was reported as 3 days.9Richards GA Murphy S Jobson R et al.Unexpected Ebola virus in a tertiary setting: clinical and epidemiologic aspects.Crit Care Med. 2000; 28: 240-244Crossref PubMed Scopus (86) Google Scholar However, a review of unpublished notes confirmed that this individual's presumed exposure was via a central venous catheter placement that occurred on Oct 29, and she first became ill on Nov 2. Therefore, the corrected incubation period is 4 days. The incubation period range was 5–12 days for the three individuals with percutaneous exposure. In one publication detailing two cases, the minimum incubation period includes 3 days because both individuals were exposed to the index patient on multiple days.10Liddell AM Davey Jr, RT Mehta AK et al.Characteristics and clinical management of a cluster of 3 patients with Ebola virus disease, including the first domestically acquired cases in the United States.Ann Intern Med. 2015; 163: 81-90Crossref PubMed Scopus (98) Google Scholar We performed three additional analyses (appendix pp 2–6). First, we identified another 17 publications containing aggregate data on incubation periods described in EVD outbreaks as opposed to discrete episodes of exposure; of these, 1860 distinct EVD cases were identified with incubation period information, for which the weighted incubation period was 10·5 days. Second, we analysed available incubation period data of 512 confirmed cases from five EVD outbreaks from the last ten years and found that the mean and median incubation periods of the gamma distributions fitted to the cases was 10 days (SD 5·3 days). No clearly described instances of transmission in less than 4 days were found from either of these two analyses. Finally, we performed a literature review of experimental infection in non-human primates, which found that 103 (98%) of 105 non-human primates injected with lethal doses of EBOV showed initial signs of illness 3 or more days after injection (appendix pp 5–6). As the illness course of EVD in non-human primates is accelerated compared with humans, this finding supports the hypothesis that the minimum incubation period for EBOV in humans is longer than 2 days in cases of needlestick exposure, and probably even longer for mucous membrane exposures. Our analysis of incubation period data from individual cases of EVD, published and unpublished EVD outbreak data, and published non-human primate data supports the conclusion that the minimum incubation period of EBOV in humans is likely to be 4 days. Accordingly, epidemiological investigations of EVD outbreaks that encounter cases where the incubation period is suspected to be shorter than 4 days should clarify whether these cases and their suspected source patients share a common origin of infection (eg, common source patient) that had not been previously identified. Additionally, whole-genome sequencing on blood samples from the patient and suspected source patients might help to clarify whether they are truly epidemiologically linked. Available tools such as the Ebola Exposure Window Calculator could assist investigators in clarifying the precise dates of exposure and the potential for recall bias in such situations.11Whitesell A Bustamante ND Stewart M et al.Development and implementation of the Ebola Exposure Window Calculator: a tool for Ebola virus disease outbreak field investigations.PLoS One. 2021; 16e0255631Crossref PubMed Scopus (0) Google Scholar Such a strategy would serve to both identify the highest-risk contacts as well as conserve scarce resources during outbreaks. JGB was president of the American Society of Tropical Medicine and Hygiene from 2019–2020. All other authors declare no competing interests. Download .pdf (.22 MB) Help with pdf files Supplementary appendix