scholarly journals Diagnostics for Lassa fever virus: a genetically diverse pathogen found in low-resource settings

2019 ◽  
Vol 4 (Suppl 2) ◽  
pp. e001116 ◽  
Author(s):  
Laura T Mazzola ◽  
Cassandra Kelly-Cirino
Keyword(s):  
Diagnostic Tests ◽  
Lassa Fever ◽  
Fever Virus ◽  
Genomic Diversity ◽  
Nucleic Acid Amplification ◽  
Detection Sensitivity ◽  
Research Use ◽  
Low Resource Settings ◽  
Low Resource ◽  
Lassa Fever Virus

Lassa fever virus (LASV) causes acute viral haemorrhagic fever with symptoms similar to those seen with Ebola virus infections. LASV is endemic to West Africa and is transmitted through contact with excretions of infected Mastomys natalensis rodents and other rodent species. Due to a high fatality rate, lack of treatment options and difficulties with prevention and control, LASV is one of the high-priority pathogens included in the WHO R&D Blueprint. The WHO LASV vaccine strategy relies on availability of effective diagnostic tests. Current diagnostics for LASV include in-house and commercial (primarily research-only) laboratory-based serological and nucleic acid amplification tests. There are two commercially available (for research use only) rapid diagnostic tests (RDTs), and a number of multiplex panels for differential detection of LASV infection from other endemic diseases with similar symptoms have been evaluated. However, a number of diagnostic gaps remain. Lineage detection is a challenge due to the genomic diversity of LASV, as pan-lineage sensitivity for both molecular and immunological detection is necessary for surveillance and outbreak response. While pan-lineage ELISA and RDTs are commercially available (for research use only), validation and external quality assessment (EQA) is needed to confirm detection sensitivity for all known or relevant strains. Variable sensitivity of LASV PCR tests also highlights the need for improved validation and EQA. Given that LASV outbreaks typically occur in low-resource settings, more options for point-of-care testing would be valuable. These requirements should be taken into account in target product profiles for improved LASV diagnostics.

Molecular Detection and Characterisation of Lassa Fever Virus among Patients Attending Tertiary Hospitals in Jos, Central Nigeria

2018 ◽  
Vol 28 (4) ◽  
pp. 1-8
Author(s):  
Solomon Chuwang Chollom ◽  
Daniel Zanyu Egah ◽  
Patricial Lar ◽  
Sophia Osawe ◽  
Alash’le Abimiku
Keyword(s):  
Molecular Detection ◽  
Lassa Fever ◽  
Fever Virus ◽  
Lassa Fever Virus ◽  
Tertiary Hospitals

Lassa Fever Virus in Senegal

1988 ◽  
Vol 157 (3) ◽  
pp. 605-605 ◽  
Author(s):  
J. F. Saluzzo ◽  
F. Adam ◽  
J. B. McCormick ◽  
J. P. Digoutte
Keyword(s):  
Lassa Fever ◽  
Fever Virus ◽  
Lassa Fever Virus

scholarly journals Outbreak of Measles in vaccinated population in Southeastern Nigeria

2021 ◽  
Vol 22 (3) ◽  
pp. 336-343
Author(s):  
J.A. Shenge ◽  
G.N. Odaibo ◽  
D.O. Olaleye
Keyword(s):  
Rural Communities ◽  
Cell Lines ◽  
Measles Virus ◽  
Venous Blood ◽  
Febrile Illness ◽  
Lassa Fever ◽  
Fever Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Southeastern Nigeria ◽  
Lassa Fever Virus

Background: Outbreaks of respiratory disease, febrile illness and rash occurred in two adjoining rural communities of Imo State, Southeastern, Nigeria, at different times between 2006 and 2020. Laboratory investigation was carried out to determine the aetiological agent of the outbreak. Methodology: Oropharyngeal swabs were collected from 6 individuals showing symptoms of disease, within 3-4 days of appearance of rash. Venous blood samples were also collected from a total of 41 symptomatic persons, their contacts and individuals with resolved infections. Swabs were inoculated into Vero, HEp-2c, B95a and MDCK cell lines. Sera were analyzed using enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G and M to rubella and measles viruses, while immunofluorescence assay was used to detect Lassa fever virus immunoglobulins. Descriptive data were analyzed using the Statistical Package for the Social Sciences (SPSS). Results: Four of the 6 (66.7%) swab samples showed viral activity or cytopathic effect characterized by clumping of cells in Vero cells while 2 (33.3%) in Hep-2c characterized by rounding up of cells. Thirty-nine (95.1%) sera were positive for measles IgG while 13 (31.7%) were positive for IgM. Thirty-six (87.8%) sera were positive for rubella IgG but none was positive for IgM. None of the sera was positive for Lassa fever virus IgG and IgM. Conclusion: Measles virus was responsible for the outbreak among previously vaccinated population in the communities, while Rubella and Lassa fever viruses were excluded as the etiological agents of the outbreak. Keywords: Epidemics; IgG and IgM; Cell lines; Vaccination; Measles virus   French title: Épidémie de rougeole dans la population vaccinée du sud-est du Nigéria Contexte: Des flambées de maladies respiratoires, de maladies fébriles et d'éruptions cutanées sont survenues dans deux communautés rurales voisines de l'État d'Imo, dans le sud-est du Nigéria, à des moments différents entre 2006 et 2020. Une enquête en laboratoire a été menée pour déterminer l'agent étiologique de l'épidémie. Méthodologie: Des écouvillons oropharyngés ont été prélevés sur 6 individus présentant des symptômes de maladie, dans les 3 à 4 jours suivant l'apparition de l'éruption cutanée. Des échantillons de sang veineux ont également été prélevés sur un total de 41 personnes symptomatiques, leurs contacts et des personnes souffrant d'infections résolues. Des écouvillons ont été inoculés dans des lignées cellulaires Vero, HEp-2c, B95a et MDCK. Les sérums ont été analysés en utilisant un test immuno-enzymatique (ELISA) pour les immunoglobulines G et M contre les virus de la rubéole et de la rougeole, tandis que le test d'immunofluorescence a été utilisé pour détecter les immunoglobulines du virus de la fièvre de Lassa. Les données descriptives ont été analysées à l'aide du progiciel statistique pour les sciences sociales (SPSS). Résultats: Quatre des 6 échantillons sur écouvillon (66,7%) ont montré une activité virale ou un effet cytopathique caractérisé par l'agglutination des cellules dans les cellules Vero, tandis que 2 (33,3%) dans Hep-2c étaient caractérisés par un arrondissement des cellules. Trente-neuf (95,1%) sérums étaient positifs pour les IgG contre la rougeole tandis que 13 (31,7%) étaient positifs pour les IgM. Trente-six (87,8%) sérums étaient positifs pour les IgG contre la rubéole, mais aucun n'était positif pour les IgM. Aucun des sérums n'était positif pour les IgG et IgM du virus de la fièvre de Lassa. Conclusion: Le virus de la rougeole était responsable de l'épidémie parmi la population précédemment vaccinée dans les communautés, tandis que les virus de la rubéole et de la fièvre de Lassa ont été exclus comme agents étiologiques de l'épidémie. Mots clés: épidémies; IgG et IgM; Lignées cellulaires; Vaccination; Virus de la rougeole

scholarly journals Boosting understanding of Lassa Fever virus epidemiology: Field testing a novel assay to identify past Lassa Fever virus infection in blood and oral fluids of survivors and unexposed controls in Sierra Leone

2021 ◽  
Vol 15 (3) ◽  
pp. e0009255
Author(s):  
Onome Akpogheneta ◽  
Steve Dicks ◽  
Donald Grant ◽  
Zainab Kanneh ◽  
Brima Jusu ◽  
...  
Keyword(s):  
Sierra Leone ◽  
Sensitivity And Specificity ◽  
Large Scale ◽  
Oral Fluid ◽  
Field Testing ◽  
Lassa Fever ◽  
Fever Virus ◽  
World Health ◽  
Hospitalised Patients ◽  
Lassa Fever Virus

Background Despite identification 50 years ago, the true burden of Lassa Fever (LF) across Africa remains undefined for reasons including research focus on hospitalised patients, lack of validated field-feasible tools which reliably identify past infection, and the fact that all assays require blood samples making large-scale surveys difficult. Designated a priority pathogen of epidemic potential requiring urgent research by the World Health Organisation, a better understanding of LF sero-epidemiology is essential to developing and evaluating new interventions including vaccines. We describe the first field testing of a novel species-neutral Double Antigen Binding Assay (DABA) designed to detect antibodies to LF in plasma and oral fluid. Methodology/Principal findings Paired plasma and oral fluid were collected in Sierra Leone from survivors discharged from Kenema Government Hospital Lassa Fever Unit between 1980 and 2018, and from controls recruited in Freetown in 2019. Epidemiological sensitivity and specificity of the DABA measured against historical diagnosis in survivors and self-declared non-exposed controls was 81.7% (95% CI 70.7%– 89.9%) and 83.3% (72.7%- 91.1%) respectively in plasma, and 71.8% (60.0%– 81.9%) and 83.3% (72.7%– 91.1%) respectively in oral fluid. Antibodies were identified in people infected up to 15 years and, in one case, 40 years previously. Participants found oral fluid collection easy and painless with 80% happy to give an oral fluid sample regularly. Conclusions/Significance Given the difficulties of assay validation in a resource-limited setting, including unexpected exposures and diagnostics of varying accuracy, the new assay performed well in both plasma and oral fluid. Sensitivity and specificity are expected to be higher when case/control ascertainment is more definitive and further work is planned to investigate this. Even at the performance levels achieved, the species-neutral DABA has the potential to facilitate the large-scale seroprevalence surveys needed to underpin essential developments in LF control, as well as support zoonotic investigations.

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