A real-time reverse-transcription PCR (RRT-PCR) was developed to detect and pathotype avian param... more A real-time reverse-transcription PCR (RRT-PCR) was developed to detect and pathotype avian paramyxovirus type 1 (APMV-1), also known as Newcastle disease virus (NDV), which had been grown in embryonated fowls' eggs. Two pairs of probes, VRP1 with ARP1 and VRP2 with ARP2, each with either the 'universal base' 2' deoxyinosine incorporated or both inosines and locked nucleic acids (LNAs) incorporated, were designed to detect, respectively, a diverse range of virulent and avirulent viral templates that included the region coding for the fusion protein cleavage site. Oligonucleotide VRP1 hybridised with 76 of the 84 virulent isolates tested, while VRP2 detected 82, including 17 isolates with five or six template-probe mismatches. An alternative conventional probe, VRP3, with no inosine bases or LNAs, failed to hybridise 7 of 13 isolates, all of which tested positive with VRP2. Real-time assays with ARP1 showed that it detected 21 of the 28 avirulent isolates tested, and ARP2 detected 22/28, including one present in a mixture with virulent NDV. Neither probe was able to detect those isolates that were classified in genogroup six. All probes were specific for detecting either virulent or avirulent NDV. A specific PCR fragment of the predicted size was obtained, using the primer set designed for this study, with the 112 NDV isolates tested, including those in genogroup six. This assay demonstrates a rapid means for simultaneous detection and pathotyping of notifiable avian disease due to NDV.
Crimean-Congo hemorrhagic fever virus (CCHFV) is a World Health Organization priority pathogen. C... more Crimean-Congo hemorrhagic fever virus (CCHFV) is a World Health Organization priority pathogen. CCHFV infections cause a highly lethal hemorrhagic fever for which specific treatments and vaccines are urgently needed. Here, we characterize the human immune response to natural CCHFV infection to identify potent neutralizing monoclonal antibodies (nAbs) targeting the viral glycoprotein. Competition experiments showed that these nAbs bind six distinct antigenic sites in the Gc subunit. These sites were further delineated through mutagenesis and mapped onto a prefusion model of Gc. Pairwise screening identified combinations of non-competing nAbs that afford synergistic neutralization. Further enhancements in neutralization breadth and potency were attained by physically linking variable domains of synergistic nAb pairs through bispecific antibody (bsAb) engineering. Although multiple nAbs protected mice from lethal CCHFV challenge in pre- or post-exposure prophylactic settings, only a single bsAb, DVD-121-801, afforded therapeutic protection. DVD-121-801 is a promising candidate suitable for clinical development as a CCHFV therapeutic.
The risk for the emergence of novel viral zoonotic diseases in animals and humans in Uganda is hi... more The risk for the emergence of novel viral zoonotic diseases in animals and humans in Uganda is high given its geographical location with high biodiversity. We aimed to identify and characterize viruses in 175 blood samples from cattle selected in Uganda using molecular approaches. We identified 8 viral species belonging to 4 families (Flaviviridae, Peribunyaviridae, Reoviridae and Rhabdoviridae) and 6 genera (Hepacivirus, Pestivirus, Orthobunyavirus, Coltivirus, Dinovernavirus and Ephemerovirus). Four viruses were highly divergent and tetantively named Zikole virus (Family: Flaviviridae), Zeboroti virus (Family: Reoviridae), Zebtine virus (Family: Rhabdoviridae) and Kokolu virus (Family: Rhabdoviridae). In addition, Bovine hepacivirus, Obodhiang virus, Aedes pseudoscutellaris reovirus and Schmallenberg virus were identified for the first time in Ugandan cattle. We report 8 viral species belonging to 4 viral families including divergent ones in the blood of cattle in Uganda. Hence, cattle may be reservoir hosts for likely emergence of novel viruses with pathogenic potential to cause zoonotic diseases in different species with serious public health implications.
The American Journal of Tropical Medicine and Hygiene
ABSTRACT. In 2016, an outbreak of Rift Valley fever was reported in the Kabale District in Uganda... more ABSTRACT. In 2016, an outbreak of Rift Valley fever was reported in the Kabale District in Uganda for the first time in 48 years. Three human cases were confirmed by polymerase chain reaction, and subsequent serological investigations revealed an overall IgG seropositivity of 13% in humans and 13% in animals. In response to this reemergence, we designed a countrywide survey to determine the seropositivity of anti-Rift Valley fever virus (RVFV) IgG antibodies in livestock. Samples were collected from 27 districts and tested for RVFV anti-IgG antibodies. A total of 3,181 livestock samples were tested, of which 54.4% were cattle (1,732 of 3,181), 34.3% were goats (1,091 of 3,181), and 11.3% were sheep (358 of 3,181). Overall RVFV seropositivity was 6.9% (221 of 3,181). Seroprevalence was greater in cattle (10.7%) compared with goats (2.6%) and sheep (2.0%), among females (7.5%) compared with males (5.2%), and among adults (7.6%) compared with juveniles (4.9%) and nurslings (6.4%). Exot...
Background Historically, malaria has been the predominant cause of acute febrile illness (AFI) in... more Background Historically, malaria has been the predominant cause of acute febrile illness (AFI) in sub-Saharan Africa. However, during the last two decades, malaria incidence has declined due to concerted public health control efforts, including the widespread use of rapid diagnostic tests leading to increased recognition of non-malarial AFI etiologies. Our understanding of non-malarial AFI is limited due to lack of laboratory diagnostic capacity. We aimed to determine the etiology of AFI in three distinct regions of Uganda. Methods A prospective clinic-based study that enrolled participants from April 2011 to January 2013 using standard diagnostic tests. Participant recruitment was from St. Paul’s Health Centre (HC) IV, Ndejje HC IV, and Adumi HC IV in the western, central and northern regions, which differ by climate, environment, and population density. A Pearson's chi-square test was used to evaluate categorical variables, while a two-sample t-test and Krukalis-Wallis test we...
SUMMARY Background: Viruses that cause acute febrile illness (AFI) in sub-Saharan Africa cause a ... more SUMMARY Background: Viruses that cause acute febrile illness (AFI) in sub-Saharan Africa cause a spectrum of disease from mild to life-threatening. Viral infection is often undiagnosed, as routine diagnostics are insufficient to capture the diversity of circulating pathogens. Methods: 1281 patients with fever of 2-7 days were prospectively recruited from three sites in Uganda as part of the CDC-UVRI AFI Study and screened with enhanced diagnostics. Plasma from 233 undiagnosed patients was analysed using metagenomic next-generation sequencing (mNGS). Confirmatory testing was carried out by PCR and serology. Findings: Thirty-eight viral pathogens were identified by mNGS in 35/233 (15%) undiagnosed patients including Measles, Hepatitis A/B/E viruses, Human immunodeficiency virus-1, Rhinovirus, Rotavirus-like virus, Human herpesvirus 6B, Human parainfluenza virus 3 and Enteroviruses. Four high-consequence arboviruses were found in six patients; Crimean-Congo haemorrhagic fever virus, Ri...
The SARS-CoV-2 virus, the agent of COVID-19, caused unprecedented loss of lives and economic decl... more The SARS-CoV-2 virus, the agent of COVID-19, caused unprecedented loss of lives and economic decline worldwide. Although the introduction of public health measures, vaccines, diagnostics, and therapeutics disrupted the spread of the SARS-CoV-2, the emergence of variants poses substantial threat. This study traced SARS-CoV-2 variants circulating in Uganda by July 2021 to inform the necessity for refinement of the intervention medical products. A comprehensivein silicoanalysis of the SARS-CoV-2 genomes detected in clinical samples collected from COVID-19 patients in Uganda revealed occurrence of structural protein variants with potential of escaping detection, resisting antibody therapy, or increased infectivity. The genome sequence dataset was retrieved from the GISAID database and the open reading frame encoding the spike, envelope, membrane, or nucleocapsid proteins was translated. The obtained protein sequences were aligned and inspected for existence of variants. The variant posi...
JAIDS Journal of Acquired Immune Deficiency Syndromes
Background: The immunopathology of disseminated HIV-associated tuberculosis (HIV/TB), a leading c... more Background: The immunopathology of disseminated HIV-associated tuberculosis (HIV/TB), a leading cause of critical illness and death among persons living with HIV in sub-Saharan Africa, is incompletely understood. Reflective of hematogenously disseminated TB, detection of lipoarabinomannan (LAM) in urine is associated with greater bacillary burden and poor outcomes in adults with HIV/TB. Methods: We determined the relationship between detection of urine TB-LAM, organ dysfunction, and host immune responses in a prospective cohort of adults hospitalized with severe HIV/TB in Uganda. Generalized additive models were used to analyze the association between urine TB-LAM grade and concentrations of 14 soluble immune mediators. Whole-blood RNA-sequencing data were used to compare transcriptional profiles between patients with high- vs. low-grade TB-LAM results. Results: Among 157 hospitalized persons living with HIV, 40 (25.5%) had positive urine TB-LAM testing. Higher TB-LAM grade was asso...
Despite causing numerous large outbreaks in the 20th century, few isolates of o’nyong nyong virus... more Despite causing numerous large outbreaks in the 20th century, few isolates of o’nyong nyong virus (ONNV) have been fully sequenced. Here, we report the complete genome sequence of an isolate of ONNV obtained from a febrile patient in northwest Uganda in 2017, designated ONNV UVRI0804.
A real-time reverse-transcription PCR (RRT-PCR) was developed to detect and pathotype avian param... more A real-time reverse-transcription PCR (RRT-PCR) was developed to detect and pathotype avian paramyxovirus type 1 (APMV-1), also known as Newcastle disease virus (NDV), which had been grown in embryonated fowls' eggs. Two pairs of probes, VRP1 with ARP1 and VRP2 with ARP2, each with either the 'universal base' 2' deoxyinosine incorporated or both inosines and locked nucleic acids (LNAs) incorporated, were designed to detect, respectively, a diverse range of virulent and avirulent viral templates that included the region coding for the fusion protein cleavage site. Oligonucleotide VRP1 hybridised with 76 of the 84 virulent isolates tested, while VRP2 detected 82, including 17 isolates with five or six template-probe mismatches. An alternative conventional probe, VRP3, with no inosine bases or LNAs, failed to hybridise 7 of 13 isolates, all of which tested positive with VRP2. Real-time assays with ARP1 showed that it detected 21 of the 28 avirulent isolates tested, and ARP2 detected 22/28, including one present in a mixture with virulent NDV. Neither probe was able to detect those isolates that were classified in genogroup six. All probes were specific for detecting either virulent or avirulent NDV. A specific PCR fragment of the predicted size was obtained, using the primer set designed for this study, with the 112 NDV isolates tested, including those in genogroup six. This assay demonstrates a rapid means for simultaneous detection and pathotyping of notifiable avian disease due to NDV.
Crimean-Congo hemorrhagic fever virus (CCHFV) is a World Health Organization priority pathogen. C... more Crimean-Congo hemorrhagic fever virus (CCHFV) is a World Health Organization priority pathogen. CCHFV infections cause a highly lethal hemorrhagic fever for which specific treatments and vaccines are urgently needed. Here, we characterize the human immune response to natural CCHFV infection to identify potent neutralizing monoclonal antibodies (nAbs) targeting the viral glycoprotein. Competition experiments showed that these nAbs bind six distinct antigenic sites in the Gc subunit. These sites were further delineated through mutagenesis and mapped onto a prefusion model of Gc. Pairwise screening identified combinations of non-competing nAbs that afford synergistic neutralization. Further enhancements in neutralization breadth and potency were attained by physically linking variable domains of synergistic nAb pairs through bispecific antibody (bsAb) engineering. Although multiple nAbs protected mice from lethal CCHFV challenge in pre- or post-exposure prophylactic settings, only a single bsAb, DVD-121-801, afforded therapeutic protection. DVD-121-801 is a promising candidate suitable for clinical development as a CCHFV therapeutic.
The risk for the emergence of novel viral zoonotic diseases in animals and humans in Uganda is hi... more The risk for the emergence of novel viral zoonotic diseases in animals and humans in Uganda is high given its geographical location with high biodiversity. We aimed to identify and characterize viruses in 175 blood samples from cattle selected in Uganda using molecular approaches. We identified 8 viral species belonging to 4 families (Flaviviridae, Peribunyaviridae, Reoviridae and Rhabdoviridae) and 6 genera (Hepacivirus, Pestivirus, Orthobunyavirus, Coltivirus, Dinovernavirus and Ephemerovirus). Four viruses were highly divergent and tetantively named Zikole virus (Family: Flaviviridae), Zeboroti virus (Family: Reoviridae), Zebtine virus (Family: Rhabdoviridae) and Kokolu virus (Family: Rhabdoviridae). In addition, Bovine hepacivirus, Obodhiang virus, Aedes pseudoscutellaris reovirus and Schmallenberg virus were identified for the first time in Ugandan cattle. We report 8 viral species belonging to 4 viral families including divergent ones in the blood of cattle in Uganda. Hence, cattle may be reservoir hosts for likely emergence of novel viruses with pathogenic potential to cause zoonotic diseases in different species with serious public health implications.
The American Journal of Tropical Medicine and Hygiene
ABSTRACT. In 2016, an outbreak of Rift Valley fever was reported in the Kabale District in Uganda... more ABSTRACT. In 2016, an outbreak of Rift Valley fever was reported in the Kabale District in Uganda for the first time in 48 years. Three human cases were confirmed by polymerase chain reaction, and subsequent serological investigations revealed an overall IgG seropositivity of 13% in humans and 13% in animals. In response to this reemergence, we designed a countrywide survey to determine the seropositivity of anti-Rift Valley fever virus (RVFV) IgG antibodies in livestock. Samples were collected from 27 districts and tested for RVFV anti-IgG antibodies. A total of 3,181 livestock samples were tested, of which 54.4% were cattle (1,732 of 3,181), 34.3% were goats (1,091 of 3,181), and 11.3% were sheep (358 of 3,181). Overall RVFV seropositivity was 6.9% (221 of 3,181). Seroprevalence was greater in cattle (10.7%) compared with goats (2.6%) and sheep (2.0%), among females (7.5%) compared with males (5.2%), and among adults (7.6%) compared with juveniles (4.9%) and nurslings (6.4%). Exot...
Background Historically, malaria has been the predominant cause of acute febrile illness (AFI) in... more Background Historically, malaria has been the predominant cause of acute febrile illness (AFI) in sub-Saharan Africa. However, during the last two decades, malaria incidence has declined due to concerted public health control efforts, including the widespread use of rapid diagnostic tests leading to increased recognition of non-malarial AFI etiologies. Our understanding of non-malarial AFI is limited due to lack of laboratory diagnostic capacity. We aimed to determine the etiology of AFI in three distinct regions of Uganda. Methods A prospective clinic-based study that enrolled participants from April 2011 to January 2013 using standard diagnostic tests. Participant recruitment was from St. Paul’s Health Centre (HC) IV, Ndejje HC IV, and Adumi HC IV in the western, central and northern regions, which differ by climate, environment, and population density. A Pearson's chi-square test was used to evaluate categorical variables, while a two-sample t-test and Krukalis-Wallis test we...
SUMMARY Background: Viruses that cause acute febrile illness (AFI) in sub-Saharan Africa cause a ... more SUMMARY Background: Viruses that cause acute febrile illness (AFI) in sub-Saharan Africa cause a spectrum of disease from mild to life-threatening. Viral infection is often undiagnosed, as routine diagnostics are insufficient to capture the diversity of circulating pathogens. Methods: 1281 patients with fever of 2-7 days were prospectively recruited from three sites in Uganda as part of the CDC-UVRI AFI Study and screened with enhanced diagnostics. Plasma from 233 undiagnosed patients was analysed using metagenomic next-generation sequencing (mNGS). Confirmatory testing was carried out by PCR and serology. Findings: Thirty-eight viral pathogens were identified by mNGS in 35/233 (15%) undiagnosed patients including Measles, Hepatitis A/B/E viruses, Human immunodeficiency virus-1, Rhinovirus, Rotavirus-like virus, Human herpesvirus 6B, Human parainfluenza virus 3 and Enteroviruses. Four high-consequence arboviruses were found in six patients; Crimean-Congo haemorrhagic fever virus, Ri...
The SARS-CoV-2 virus, the agent of COVID-19, caused unprecedented loss of lives and economic decl... more The SARS-CoV-2 virus, the agent of COVID-19, caused unprecedented loss of lives and economic decline worldwide. Although the introduction of public health measures, vaccines, diagnostics, and therapeutics disrupted the spread of the SARS-CoV-2, the emergence of variants poses substantial threat. This study traced SARS-CoV-2 variants circulating in Uganda by July 2021 to inform the necessity for refinement of the intervention medical products. A comprehensivein silicoanalysis of the SARS-CoV-2 genomes detected in clinical samples collected from COVID-19 patients in Uganda revealed occurrence of structural protein variants with potential of escaping detection, resisting antibody therapy, or increased infectivity. The genome sequence dataset was retrieved from the GISAID database and the open reading frame encoding the spike, envelope, membrane, or nucleocapsid proteins was translated. The obtained protein sequences were aligned and inspected for existence of variants. The variant posi...
JAIDS Journal of Acquired Immune Deficiency Syndromes
Background: The immunopathology of disseminated HIV-associated tuberculosis (HIV/TB), a leading c... more Background: The immunopathology of disseminated HIV-associated tuberculosis (HIV/TB), a leading cause of critical illness and death among persons living with HIV in sub-Saharan Africa, is incompletely understood. Reflective of hematogenously disseminated TB, detection of lipoarabinomannan (LAM) in urine is associated with greater bacillary burden and poor outcomes in adults with HIV/TB. Methods: We determined the relationship between detection of urine TB-LAM, organ dysfunction, and host immune responses in a prospective cohort of adults hospitalized with severe HIV/TB in Uganda. Generalized additive models were used to analyze the association between urine TB-LAM grade and concentrations of 14 soluble immune mediators. Whole-blood RNA-sequencing data were used to compare transcriptional profiles between patients with high- vs. low-grade TB-LAM results. Results: Among 157 hospitalized persons living with HIV, 40 (25.5%) had positive urine TB-LAM testing. Higher TB-LAM grade was asso...
Despite causing numerous large outbreaks in the 20th century, few isolates of o’nyong nyong virus... more Despite causing numerous large outbreaks in the 20th century, few isolates of o’nyong nyong virus (ONNV) have been fully sequenced. Here, we report the complete genome sequence of an isolate of ONNV obtained from a febrile patient in northwest Uganda in 2017, designated ONNV UVRI0804.
Uploads
Papers by Julius Lutwama