scholarly journals Systematics, Ecology, and Host Switching: Attributes Affecting Emergence of the Lassa Virus in Rodents across Western Africa

Viruses ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 312
Author(s):  
Ayodeji Olayemi ◽  
Elisabeth Fichet-Calvet
Keyword(s):  
Virus Evolution ◽  
Lassa Fever ◽  
Host Switching ◽  
Lassa Virus ◽  
Western Africa ◽  
Key Aspects ◽  
Rodent Abundance

Ever since it was established that rodents serve as reservoirs of the zoonotic Lassa virus (LASV), scientists have sought to answer the questions: which populations of rodents carry the virus? How do fluctuations in LASV prevalence and rodent abundance influence Lassa fever outbreaks in humans? What does it take for the virus to adopt additional rodent hosts, proliferating what already are devastating cycles of rodent-to-human transmission? In this review, we examine key aspects of research involving the biology of rodents that affect their role as LASV reservoirs, including phylogeography, demography, virus evolution, and host switching. We discuss how this knowledge can help control Lassa fever and suggest further areas for investigation.

scholarly journals A Lassa Virus Live-Attenuated Vaccine Candidate Based on Rearrangement of the Intergenic Region

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Yingyun Cai ◽  
Masaharu Iwasaki ◽  
Daisuke Motooka ◽  
David X. Liu ◽  
Shuiqing Yu ◽  
...  
Keyword(s):  
Intergenic Region ◽  
Guinea Pigs ◽  
Cultured Cells ◽  
Vaccine Candidate ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Wild Type ◽  
Live Attenuated Vaccine ◽  
Attenuated Vaccine ◽  
Western Africa

ABSTRACT Lassa virus (LASV) poses a significant public health problem within the regions of Lassa fever endemicity in Western Africa. LASV infects several hundred thousand individuals yearly, and a considerable number of Lassa fever cases are associated with high morbidity and lethality. No approved LASV vaccine is available, and current therapy is limited to an off-label usage of ribavirin that is only partially effective and associated with significant side effects. The impact of Lassa fever on human health, together with the limited existing countermeasures, highlights the importance of developing effective vaccines against LASV. Here, we present the development and characterization of a recombinant LASV (rLASV) vaccine candidate [rLASV(IGR/S-S)], which is based on the presence of the noncoding intergenic region (IGR) of the small (S) genome segment (S-IGR) in both large (L) and S LASV segments. In cultured cells, rLASV(IGR/S-S) was modestly less fit than wild-type rLASV (rLASV-WT). rLASV(IGR/S-S) was highly attenuated in guinea pigs, and a single subcutaneous low dose of the virus completely protected against otherwise lethal infection with LASV-WT. Moreover, rLASV(IGR/S-S) was genetically stable during serial passages in cultured cells. These findings indicate that rLASV(IGR/S-S) can be developed into a LASV live-attenuated vaccine (LAV) that has the same antigenic composition as LASV-WT and a well-defined mechanism of attenuation that overcomes concerns about increased virulence that could be caused by genetic changes in the LAV during multiple rounds of multiplication. IMPORTANCE Lassa virus (LASV), the causative agent of Lassa fever, infects several hundred thousand people in Western Africa, resulting in many lethal Lassa fever cases. No U.S. Food and Drug Administration-licensed countermeasures are available to prevent or treat LASV infection. We describe the generation of a novel LASV live-attenuated vaccine candidate rLASV(IGR/S-S), which is based on the replacement of the large genomic segment noncoding intergenic region (IGR) with that of the small genome segment. rLASV(IGR/S-S) is less fit in cell culture than wild-type virus and does not cause clinical signs in inoculated guinea pigs. Importantly, rLASV(IGR/S-S) protects immunized guinea pigs against an otherwise lethal exposure to LASV.

Vaccines inducing immunity to Lassa virus glycoprotein and nucleoprotein protect macaques after a single shot

2019 ◽  
Vol 11 (512) ◽  
pp. eaaw3163 ◽  
Author(s):  
Mathieu Mateo ◽  
Stéphanie Reynard ◽  
Xavier Carnec ◽  
Alexandra Journeaux ◽  
Nicolas Baillet ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Measles Virus ◽  
Vaccine Candidate ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Single Shot ◽  
Efficacy Analysis ◽  
Western Africa ◽  
Efficacious Vaccine

Lassa fever is a major threat in Western Africa. The large number of people living at risk for this disease calls for the development of a vaccine against Lassa virus (LASV). We generated live-attenuated LASV vaccines based on measles virus and Mopeia virus platforms and expressing different LASV antigens, with the aim to develop a vaccine able to protect after a single shot. We compared the efficacy of these vaccines against LASV in cynomolgus monkeys. The vaccines were well tolerated and protected the animals from LASV infection and disease after a single immunization but with varying efficacy. Analysis of the immune responses showed that complete protection was associated with robust secondary T cell and antibody responses against LASV. Transcriptomic and proteomic analyses showed an early activation of innate immunity and T cell priming after immunization with the most effective vaccines, with changes detectable as early as 2 days after immunization. The most efficacious vaccine candidate, a measles vector simultaneously expressing LASV glycoprotein and nucleoprotein, has been selected for further clinical evaluation.

scholarly journals Lassa Virus Infection in Experimentally Infected Marmosets: Liver Pathology and Immunophenotypic Alterations in Target Tissues

2007 ◽  
Vol 81 (12) ◽  
pp. 6482-6490 ◽  
Author(s):  
Ricardo Carrion ◽  
Kathleen Brasky ◽  
Keith Mansfield ◽  
Curtis Johnson ◽  
Monica Gonzales ◽  
...  
Keyword(s):  
Systemic Disease ◽  
Common Marmoset ◽  
Lassa Fever ◽  
Hepatic Necrosis ◽  
Hepatocyte Proliferation ◽  
Lassa Virus ◽  
Primate Model ◽  
Common Marmosets ◽  
Western Africa ◽  
Elevated Liver Enzymes

ABSTRACT Lassa virus causes thousands of deaths annually in western Africa and is considered a potential biological weapon. In an attempt to develop a small nonhuman primate model of Lassa fever, common marmosets were subcutaneously inoculated with Lassa virus strain Josiah. This inoculation resulted in a systemic disease with clinical and morphological features mirroring those in fatal human Lassa infection: fever, weight loss, high viremia and viral RNA load in tissues, elevated liver enzymes, and severe morbidity between days 15 and 20. The most prominent histopathology findings included multifocal hepatic necrosis with mild inflammation and hepatocyte proliferation, lymphoid depletion, and interstitial nephritis. Cellular aggregates in regions of hepatocellular necrosis were largely composed of HAM56-positive macrophages, devoid of CD3-positive and CD20-positive cells, and characterized by marked reductions in the intensity of HLA-DP, DQ, DR staining. A marked reduction in the major histocompatibility complex class II expression was also observed in the lymph nodes. Immunophenotypic alterations in spleen included reductions in overall numbers of CD20-positive and CD3-positive cells and the disruption of lymphoid follicular architecture. These findings identify the common marmoset as an appropriate model of human Lassa fever and present the first experimental evidence that replication of Lassa virus in tissues is associated with alterations that would be expected to impair adaptive immunity.

scholarly journals Animal Models of Lassa Fever

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 197 ◽  
Author(s):  
Rachel A. Sattler ◽  
Slobodan Paessler ◽  
Hinh Ly ◽  
Cheng Huang
Keyword(s):  
Animal Model ◽  
Hearing Loss ◽  
Animal Models ◽  
Sensorineural Hearing Loss ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Disease Pathogenesis ◽  
Western Africa ◽  
Socioeconomic Burden

Lassa virus (LASV), the causative agent of Lassa fever, is estimated to be responsible for up to 300,000 new infections and 5000 deaths each year across Western Africa. The most recent 2018 and 2019 Nigerian outbreaks featured alarmingly high fatality rates of up to 25.4%. In addition to the severity and high fatality of the disease, a significant population of survivors suffer from long-term sequelae, such as sensorineural hearing loss, resulting in a huge socioeconomic burden in endemic regions. There are no Food and Drug Administration (FDA)-approved vaccines, and therapeutics remain extremely limited for Lassa fever. Development of countermeasures depends on relevant animal models that can develop a disease strongly mimicking the pathogenic features of Lassa fever in humans. The objective of this review is to evaluate the currently available animal models for LASV infection with an emphasis on their pathogenic and histologic characteristics as well as recent advances in the development of a suitable rodent model. This information may facilitate the development of an improved animal model for understanding disease pathogenesis of Lassa fever and for vaccine or antiviral testing.

scholarly journals A Lassa Fever Live-Attenuated Vaccine Based on Codon Deoptimization of the Viral Glycoprotein Gene

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yingyun Cai ◽  
Chengjin Ye ◽  
Benson Cheng ◽  
Aitor Nogales ◽  
Masaharu Iwasaki ◽  
...  
Keyword(s):  
Guinea Pigs ◽  
Vaccine Candidate ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Off Label Use ◽  
Wild Type ◽  
Glycoprotein Precursor ◽  
Live Attenuated Vaccine ◽  
Off Label ◽  
Western Africa

ABSTRACT Lassa virus (LASV) is endemic in Western Africa and is estimated to infect hundreds of thousands of individuals annually. A considerable number of these infections result in Lassa fever (LF), which is associated with significant morbidity and a case-fatality rate as high as 69% among hospitalized confirmed patients. U.S. Food and Drug Administration-approved LF vaccines are not available. Current antiviral treatment is limited to off-label use of a nucleoside analogue, ribavirin, that is only partially effective and associated with significant side effects. We generated and characterized a recombinant LASV expressing a codon-deoptimized (CD) glycoprotein precursor gene (GPC), rLASV-GPC/CD. Comparison of growth kinetics and peak titers showed that rLASV-GPC/CD is slightly attenuated in cell culture compared to wild-type (WT) recombinant LASV (rLASV-WT). However, rLASV-GPC/CD is highly attenuated in strain 13 and Hartley guinea pigs, as reflected by the absence of detectable clinical signs in animals inoculated with rLASV-GPC/CD. Importantly, a single subcutaneous dose of rLASV-GPC/CD provides complete protection against an otherwise lethal exposure to LASV. Our results demonstrate the feasibility of implementing a CD approach for developing a safe and effective LASV live-attenuated vaccine candidate. Moreover, rLASV-GPC/CD might provide investigators with a tool to safely study LASV outside maximum (biosafety level 4) containment, which could accelerate the elucidation of basic aspects of the molecular and cell biology of LASV and the development of novel LASV medical countermeasures. IMPORTANCE Lassa virus (LASV) infects several hundred thousand people in Western Africa, resulting in many lethal Lassa fever (LF) cases. Licensed LF vaccines are not available, and anti-LF therapy is limited to off-label use of the nucleoside analog ribavirin with uncertain efficacy. We describe the generation of a novel live-attenuated LASV vaccine candidate. This vaccine candidate is based on mutating wild-type (WT) LASV in a key region of the viral genome, the glycoprotein precursor (GPC) gene. These mutations do not change the encoded GPC but interfere with its production in host cells. This mutated LASV (rLASV-GPC/CD) behaves like WT LASV (rLASV-WT) in cell culture, but in contrast to rLASV-WT, does not cause disease in inoculated guinea pigs. Guinea pigs immunized with rLASV-GPC/CD were protected against an otherwise lethal exposure to WT LASV. Our results support the testing of this candidate vaccine in nonhuman primate models ofLF.

scholarly journals Host-Driven Phosphorylation Appears to Regulate the Budding Activity of the Lassa Virus Matrix Protein

Pathogens ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 97 ◽  
Author(s):  
Christopher Ziegler ◽  
Philip Eisenhauer ◽  
Inessa Manuelyan ◽  
Marion Weir ◽  
Emily Bruce ◽  
...  
Keyword(s):  
Protein Function ◽  
Matrix Protein ◽  
Rna Virus ◽  
Hemorrhagic Fever ◽  
Polymerase Activity ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Protein Z ◽  
Western Africa ◽  
Z Protein

Lassa mammarenavirus (LASV) is an enveloped RNA virus that can cause Lassa fever, an acute hemorrhagic fever syndrome associated with significant morbidity and high rates of fatality in endemic regions of western Africa. The arenavirus matrix protein Z has several functions during the virus life cycle, including coordinating viral assembly, driving the release of new virus particles, regulating viral polymerase activity, and antagonizing the host antiviral response. There is limited knowledge regarding how the various functions of Z are regulated. To investigate possible means of regulation, mass spectrometry was used to identify potential sites of phosphorylation in the LASV Z protein. This analysis revealed that two serines (S18, S98) and one tyrosine (Y97) are phosphorylated in the flexible N- and C-terminal regions of the protein. Notably, two of these sites, Y97 and S98, are located in (Y97) or directly adjacent to (S98) the PPXY late domain, an important motif for virus release. Studies with non-phosphorylatable and phosphomimetic Z proteins revealed that these sites are important regulators of the release of LASV particles and that host-driven, reversible phosphorylation may play an important role in the regulation of LASV Z protein function.

cccccImmunological screening of Lassa Virus among Health workers and Contacts of patients of Lassa fever in Ondo State

Immunobiology ◽  
2021 ◽  
pp. 152076
Author(s):  
Joseph Ojonugwa Shaibu ◽  
Olumuyiwa Babalola Salu ◽  
Olufemi Samuel Amoo ◽  
Ifeoma Idigbe ◽  
Adesola Zaidat Musa ◽  
...  
Keyword(s):  
Health Workers ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Ondo State

scholarly journals Lassa Virus Circulation in Small Mammal Populations in Bo District, Sierra Leone

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 28
Author(s):  
Umaru Bangura ◽  
Jacob Buanie ◽  
Joyce Lamin ◽  
Christopher Davis ◽  
Gédéon Ngiala Bongo ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Sierra Leone ◽  
Small Mammal ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Sierra Leonean ◽  
Bayesian Phylogenetic Analysis ◽  
Prevalent Species ◽  
Lineage Iv

Lassa fever is a viral hemorrhagic fever caused by the Lassa virus LASV, which was first isolated in the rodent Mastomys natalensis in 1974 in Kenema, Sierra Leone. As little is known about the abundance and the presence of LASV in rodents living in the Bo area, we carried out a small mammal longitudinal population survey. A standardized trapping session was performed in various habitats and seasons in six villages over two years (2014–2016) and samples collected were tested for arenavirus IgG and LASV. A Bayesian phylogenetic analysis was performed on sequences identified by PCR. A total of 1490 small mammals were collected, and 16 rodent species were identified, with M. natalensis (355, 24%) found to be the most prevalent species. Forty-one (2.8%) samples were IgG positive, and 31 of these were trapped in homes and 10 in surrounding vegetation. Twenty-nine of 41 seropositive rodents were M. natalensis. We detected four LASV by PCR in two villages, all found in M. natalensis. Phylogenetic analysis showed that the sequences were distributed within the Sierra Leonean clade within lineage IV, distinguishing a Bo sub-clade older than a Kenema sub-clade. Compared to other settings, we found a low abundance of M. natalensis and a low circulation of LASV in rodents in villages around Bo district.

scholarly journals Differential pathogenesis of closely related 2018 Nigerian outbreak clade III Lassa virus isolates

2021 ◽  
Vol 17 (10) ◽  
pp. e1009966
Author(s):  
Derek R. Stein ◽  
Bryce M. Warner ◽  
Jonathan Audet ◽  
Geoff Soule ◽  
Vinayakumar Siragam ◽  
...  
Keyword(s):  
Animal Models ◽  
Lassa Fever ◽  
Geographic Region ◽  
World Health ◽  
Limiting Factor ◽  
Lassa Virus ◽  
African Countries ◽  
Animal Models Of Disease ◽  
Medical Countermeasures

Nigeria continues to experience ever increasing annual outbreaks of Lassa fever (LF). The World Health Organization has recently declared Lassa virus (LASV) as a priority pathogen for accelerated research leading to a renewed international effort to develop relevant animal models of disease and effective countermeasures to reduce LF morbidity and mortality in endemic West African countries. A limiting factor in evaluating medical countermeasures against LF is a lack of well characterized animal models outside of those based on infection with LASV strain Josiah originating form Sierra Leone, circa 1976. Here we genetically characterize five recent LASV isolates collected from the 2018 outbreak in Nigeria. Three isolates were further evaluated in vivo and despite being closely related and from the same spatial / geographic region of Nigeria, only one of the three isolates proved lethal in strain 13 guinea pigs and non-human primates (NHP). Additionally, this isolate exhibited atypical pathogenesis characteristics in the NHP model, most notably respiratory failure, not commonly described in hemorrhagic cases of LF. These results suggest that there is considerable phenotypic heterogeneity in LASV infections in Nigeria, which leads to a multitude of pathogenesis characteristics that could account for differences between subclinical and lethal LF infections. Most importantly, the development of disease models using currently circulating LASV strains in West Africa are critical for the evaluation of potential vaccines and medical countermeasures.

scholarly journals Attenuated Replication of Lassa Virus Vaccine Candidate ML29 in STAT-1-/- Mice

Pathogens ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 9 ◽  
Author(s):  
Dylan Johnson ◽  
Jenny Jokinen ◽  
Igor Lukashevich
Keyword(s):  
Vaccine Development ◽  
Vaccine Candidate ◽  
Small Animal ◽  
Vero Cells ◽  
Lassa Fever ◽  
Effective Vaccine ◽  
Cell Mediated Immunity ◽  
Lassa Virus ◽  
Cell Responses ◽  
Fold Reduction

Lassa virus (LASV), a highly prevalent mammalian arenavirus endemic in West Africa, can cause Lassa fever (LF), which is responsible for thousands of deaths annually. LASV is transmitted to humans from naturally infected rodents. At present, there is not an effective vaccine nor treatment. The genetic diversity of LASV is the greatest challenge for vaccine development. The reassortant ML29 carrying the L segment from the nonpathogenic Mopeia virus (MOPV) and the S segment from LASV is a vaccine candidate under current development. ML29 demonstrated complete protection in validated animal models against a Nigerian strain from clade II, which was responsible for the worst outbreak on record in 2018. This study demonstrated that ML29 was more attenuated than MOPV in STAT1-/- mice, a small animal model of human LF and its sequelae. ML29 infection of these mice resulted in more than a thousand-fold reduction in viremia and viral load in tissues and strong LASV-specific adaptive T cell responses compared to MOPV-infected mice. Persistent infection of Vero cells with ML29 resulted in generation of interfering particles (IPs), which strongly interfered with the replication of LASV, MOPV and LCMV, the prototype of the Arenaviridae. ML29 IPs induced potent cell-mediated immunity and were fully attenuated in STAT1-/- mice. Formulation of ML29 with IPs will improve the breadth of the host’s immune responses and further contribute to development of a pan-LASV vaccine with full coverage meeting the WHO requirements.

Sign in / Sign up

Export Citation Format

Share Document