Prevalence of antibodies against Rift Valley fever virus in Kenyan wildlife

SUMMARYRift Valley fever virus (RVFV) is an arbovirus associated with periodic outbreaks, mostly on the African continent, of febrile disease accompanied by abortion in livestock, and a severe, fatal haemorrhagic syndrome in humans. However, the maintenance of the virus during the inter-epidemic period (IEP) when there is low or no disease activity detected in livestock or humans has not been determined. This study report prevalence of RVFV-neutralizing antibodies in sera (n=896) collected from 16 Kenyan wildlife species including at least 35% that were born during the 1999–2006 IEP. Specimens from seven species had detectable neutralizing antibodies against RVFV, including African buffalo, black rhino, lesser kudu, impala, African elephant, kongoni, and waterbuck. High RVFV antibody prevalence (>15%) was observed in black rhinos and ruminants (kudu, impala, buffalo, and waterbuck) with the highest titres (up to 1:1280) observed mostly in buffalo, including animals born during the IEP. All lions, giraffes, plains zebras, and warthogs tested were either negative or less than two animals in each species had low (⩽1:16) titres of RVFV antibodies. Of 249 sera collected from five wildlife species during the 2006–2007 outbreak, 16 out of 19 (84%) of the ruminant (gerenuk, waterbuck, and eland) specimens had RVFV-neutralizing titres ⩾1:80. These data provide evidence that wild ruminants are infected by RVFV but further studies are required to determine whether these animals play a role in the virus maintenance between outbreaks and virus amplification prior to a noticeable outbreak.

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Naturally Acquired Rift Valley Fever Virus Neutralizing Antibodies Predominantly Target the Gn Glycoprotein

iScience ◽

10.1016/j.isci.2020.101669 ◽

2020 ◽

Vol 23 (11) ◽

pp. 101669

Author(s):

Daniel Wright ◽

Elizabeth R. Allen ◽

Madeleine H.A. Clark ◽

John N. Gitonga ◽

Henry K. Karanja ◽

...

Keyword(s):

Rift Valley ◽

Neutralizing Antibodies ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Fever Virus ◽

Valley Fever

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Neutralizing antibodies against Rift Valley fever virus in wild antelope in far northern KwaZulu‐Natal, South Africa, indicate recent virus circulation

Transboundary and Emerging Diseases ◽

10.1111/tbed.13479 ◽

2020 ◽

Vol 67 (3) ◽

pp. 1356-1363

Author(s):

Carien Van den Bergh ◽

Estelle H. Venter ◽

Robert Swanepoel ◽

Cathariné C. Hanekom ◽

Peter N. Thompson

Keyword(s):

South Africa ◽

Rift Valley ◽

Neutralizing Antibodies ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Fever Virus ◽

Valley Fever ◽

Kwazulu Natal

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MVA Vectored Vaccines Encoding Rift Valley Fever Virus Glycoproteins Protect Mice against Lethal Challenge in the Absence of Neutralizing Antibody Responses

Vaccines ◽

10.3390/vaccines8010082 ◽

2020 ◽

Vol 8 (1) ◽

pp. 82 ◽

Cited By ~ 2

Author(s):

Elena López-Gil ◽

Sandra Moreno ◽

Javier Ortego ◽

Belén Borrego ◽

Gema Lorenzo ◽

...

Keyword(s):

Immune Response ◽

Immune Responses ◽

Cellular Immunity ◽

Rift Valley ◽

Neutralizing Antibodies ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Fever Virus ◽

Valley Fever

In vitro neutralizing antibodies have been often correlated with protection against Rift Valley fever virus (RVFV) infection. We have reported previously that a single inoculation of sucrose-purified modified vaccinia Ankara (MVA) encoding RVFV glycoproteins (rMVAGnGc) was sufficient to induce a protective immune response in mice after a lethal RVFV challenge. Protection was related to the presence of glycoprotein specific CD8+ cells, with a low-level detection of in vitro neutralizing antibodies. In this work we extended those observations aimed to explore the role of humoral responses after MVA vaccination and to study the contribution of each glycoprotein antigen to the protective efficacy. Thus, we tested the efficacy and immune responses in BALB/c mice of recombinant MVA viruses expressing either glycoprotein Gn (rMVAGn) or Gc (rMVAGc). In the absence of serum neutralizing antibodies, our data strongly suggest that protection of vaccinated mice upon the RVFV challenge can be achieved by the activation of cellular responses mainly directed against Gc epitopes. The involvement of cellular immunity was stressed by the fact that protection of mice was strain dependent. Furthermore, our data suggest that the rMVA based single dose vaccination elicits suboptimal humoral immune responses against Gn antigen since disease in mice was exacerbated upon virus challenge in the presence of rMVAGnGc or rMVAGn immune serum. Thus, Gc-specific cellular immunity could be an important component in the protection after the challenge observed in BALB/c mice, contributing to the elimination of infected cells reducing morbidity and mortality and counteracting the deleterious effect of a subneutralizing antibody immune response.

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Genetically Modified Rabies Virus Vector-Based Rift Valley Fever Virus Vaccine is Safe and Induces Efficacious Immune Responses in Mice

Viruses ◽

10.3390/v11100919 ◽

2019 ◽

Vol 11 (10) ◽

pp. 919 ◽

Cited By ~ 3

Author(s):

Zhang ◽

Hao ◽

Feng ◽

Jin ◽

Yan ◽

...

Keyword(s):

T Cells ◽

Rabies Virus ◽

Rift Valley ◽

Neutralizing Antibodies ◽

Rift Valley Fever ◽

Memory T Cells ◽

Rift Valley Fever Virus ◽

Fever Virus ◽

Igg Antibodies ◽

Valley Fever

Rift Valley fever virus (RVFV), which causes Rift Valley fever (RVF), is a mosquito-borne zoonotic pathogen that causes serious morbidity and mortality in livestock and humans. RVF is a World Health Organization (WHO) priority disease and, together with rabies, is a major health burden in Africa. Here, we present the development and characterization of an inactivated recombinant RVFV and rabies virus (RABV) vaccine candidate (rSRV9-eGn). Immunization with rSRV9-eGn stimulated the production of RVFV-specific IgG antibodies and induced humoral and cellular immunity in mice but did not induce the production of neutralizing antibodies. IgG1 and IgG2a were the main isotypes observed by IgG subtype detection, and IgG3 antibodies were not detected. The ratios of IgG1/IgG2a > 1 indicated a Type 2 humoral immune response. An effective vaccine is intended to establish a long-lived population of memory T cells, and mice generated memory cells among the proliferating T cell population after immunization with rSRV9-eGn, with effector memory T cells (TEM) as the major population. Due to the lack of prophylactic treatment experiments, it is impossible to predict whether this vaccine can protect animals from RVFV infection with only high titres of anti-RVFV IgG antibodies and no neutralizing antibodies induced, and thus, protection confirmation needs further verification. However, this RVFV vaccine designed with RABV as the vector provides ideas for the development of vaccines that prevent RVFV and RABV infections.

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Serological Evidence of Rift Valley Fever Virus Circulation in Domestic Cattle and African Buffalo in Northern Botswana (2010–2011)

Frontiers in Veterinary Science ◽

10.3389/fvets.2015.00063 ◽

2015 ◽

Vol 2 ◽

Cited By ~ 8

Author(s):

Ferran Jori ◽

Kathleen A. Alexander ◽

Mokganedi Mokopasetso ◽

Suzanne Munstermann ◽

Keabetswe Moagabo ◽

...

Keyword(s):

Rift Valley ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Fever Virus ◽

African Buffalo ◽

Serological Evidence ◽

Valley Fever

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Vaccine Efficacy of Self-Assembled Multimeric Protein Scaffold Particles Displaying the Glycoprotein Gn Head Domain of Rift Valley Fever Virus

Vaccines ◽

10.3390/vaccines9030301 ◽

2021 ◽

Vol 9 (3) ◽

pp. 301

Author(s):

Paul J. Wichgers Schreur ◽

Mirriam Tacken ◽

Benjamin Gutjahr ◽

Markus Keller ◽

Lucien van Keulen ◽

...

Keyword(s):

Rift Valley ◽

Neutralizing Antibodies ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Clinical Signs ◽

Fever Virus ◽

Valley Fever ◽

Protein Scaffold ◽

Head Domain ◽

Multimeric Protein

Compared to free antigens, antigens immobilized on scaffolds, such as nanoparticles, generally show improved immunogenicity. Conventionally, antigens are conjugated to scaffolds through genetic fusion or chemical conjugation, which may result in impaired assembly or heterogeneous binding and orientation of the antigens. By combining two emerging technologies—i.e., self-assembling multimeric protein scaffold particles (MPSPs) and bacterial superglue—these shortcomings can be overcome and antigens can be bound on particles in their native conformation. In the present work, we assessed whether this technology could improve the immunogenicity of a candidate subunit vaccine against the zoonotic Rift Valley fever virus (RVFV). For this, the head domain of glycoprotein Gn, a known target of neutralizing antibodies, was coupled on various MPSPs to further assess immunogenicity and efficacy in vivo. The results showed that the Gn head domain, when bound to the lumazine synthase-based MPSP, reduced mortality in a lethal mouse model and protected lambs, the most susceptible RVFV target animals, from viremia and clinical signs after immunization. Furthermore, the same subunit coupled to two other MPSPs (Geobacillus stearothermophilus E2 or a modified KDPG Aldolase) provided full protection in lambs as well.

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Evaluation of the Efficacy, Potential for Vector Transmission, and Duration of Immunity of MP-12, an Attenuated Rift Valley Fever Virus Vaccine Candidate, in Sheep

Clinical and Vaccine Immunology ◽

10.1128/cvi.00114-15 ◽

2015 ◽

Vol 22 (8) ◽

pp. 930-937 ◽

Cited By ~ 17

Author(s):

Myrna M. Miller ◽

Kristine E. Bennett ◽

Barbara S. Drolet ◽

Robbin Lindsay ◽

James O. Mecham ◽

...

Keyword(s):

Rift Valley ◽

Neutralizing Antibodies ◽

Rift Valley Fever ◽

Nonstructural Protein ◽

Rift Valley Fever Virus ◽

Clinical Signs ◽

Fever Virus ◽

Vector Transmission ◽

Valley Fever ◽

Virulent Challenge

ABSTRACTRift Valley fever virus (RVFV) causes serious disease in ruminants and humans in Africa. In North America, there are susceptible ruminant hosts and competent mosquito vectors, yet there are no fully licensed animal vaccines for this arthropod-borne virus, should it be introduced. Studies in sheep and cattle have found the attenuated strain of RVFV, MP-12, to be both safe and efficacious based on early testing, and a 2-year conditional license for use in U.S. livestock has been issued. The purpose of this study was to further determine the vaccine's potential to infect mosquitoes, the duration of humoral immunity to 24 months postvaccination, and the ability to prevent disease and viremia from a virulent challenge. Vaccination experiments conducted in sheep found no evidence of a potential for vector transmission to 4 North American mosquito species. Neutralizing antibodies were elicited, with titers of >1:40 still present at 24 months postvaccination. Vaccinates were protected from clinical signs and detectable viremia after challenge with virulent virus, while control sheep had fever and high-titered viremia extending for 5 days. Antibodies to three viral proteins (nucleocapsid N, the N-terminal half of glycoprotein GN, and the nonstructural protein from the short segment NSs) were also detected to 24 months using competitive enzyme-linked immunosorbent assays. This study demonstrates that the MP-12 vaccine given as a single dose in sheep generates protective immunity to a virulent challenge with antibody duration of at least 2 years, with no evidence of a risk for vector transmission.

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Protection of Sheep against Rift Valley Fever Virus and Sheep Poxvirus with a Recombinant Capripoxvirus Vaccine

Clinical and Vaccine Immunology ◽

10.1128/cvi.00220-10 ◽

2010 ◽

Vol 17 (12) ◽

pp. 1842-1849 ◽

Cited By ~ 34

Author(s):

Reuben K. Soi ◽

Fred R. Rurangirwa ◽

Travis C. McGuire ◽

Paul M. Rwambo ◽

James C. DeMartini ◽

...

Keyword(s):

Rift Valley ◽

Neutralizing Antibodies ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Viral Disease ◽

Fever Virus ◽

Recombinant Vaccines ◽

Valley Fever ◽

Genes Encoding ◽

Correct Size

ABSTRACT Rift Valley fever (RVF) is an epizootic viral disease of sheep that can be transmitted from sheep to humans, particularly by contact with aborted fetuses. A capripoxvirus (CPV) recombinant virus (rKS1/RVFV) was developed, which expressed the Rift Valley fever virus (RVFV) Gn and Gc glycoproteins. These expressed glycoproteins had the correct size and reacted with monoclonal antibodies (MAb) to native glycoproteins. Mice vaccinated with rKS1/RVFV were protected against RVFV challenge. Sheep vaccinated with rKS1/RVFV twice developed neutralizing antibodies and were significantly protected against RVFV and sheep poxvirus challenge. These findings further document the value of CPV recombinants as ruminant vaccine vectors and support the inclusion of RVFV genes encoding glycoproteins in multivalent recombinant vaccines to be used where RVF occurs.

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Seroprevalence of Rift Valley fever virus in livestock during inter-epidemic period in Egypt, 2014/15

BMC Veterinary Research ◽

10.1186/s12917-017-0993-8 ◽

2017 ◽

Vol 13 (1) ◽

Cited By ~ 17

Author(s):

Claudia Mroz ◽

Mayada Gwida ◽

Maged El-Ashker ◽

Mohamed El-Diasty ◽

Mohamed El-Beskawy ◽

...

Keyword(s):

Rift Valley ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Fever Virus ◽

Valley Fever ◽

Epidemic Period

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Serological and genomic evidence of Rift Valley fever virus during inter-epidemic periods in Mauritania

Epidemiology and Infection ◽

10.1017/s0950268816003022 ◽

2016 ◽

Vol 145 (5) ◽

pp. 1058-1068 ◽

Cited By ~ 6

Author(s):

M. RISSMANN ◽

M. EIDEN ◽

B. O. EL MAMY ◽

K. ISSELMOU ◽

B. DOUMBIA ◽

...

Keyword(s):

Rift Valley ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Simultaneous Detection ◽

Small Ruminants ◽

Fever Virus ◽

Serum Samples ◽

Valley Fever ◽

Epidemic Period ◽

And Shifts

SUMMARYRift Valley fever virus (RVFV) is an emerging pathogen of major concern throughout Africa and the Arabian Peninsula, affecting both livestock and humans. In the past recurrent epidemics were reported in Mauritania and studies focused on the analysis of samples from affected populations during acute outbreaks. To verify characteristics and presence of RVFV during non-epidemic periods we implemented a multi-stage serological and molecular analysis. Serum samples of small ruminants, cattle and camels were obtained from Mauritania during an inter-epidemic period in 2012–2013. This paper presents a comparative analysis of potential variations and shifts of antibody presence and the capability of inter-epidemic infections in Mauritanian livestock. We observed distinct serological differences between tested species (seroprevalence: small ruminants 3·8%, cattle 15·4%, camels 32·0%). In one single bovine from Nouakchott, a recent RVF infection could be identified by the simultaneous detection of IgM antibodies and viral RNA. This study indicates the occurrence of a low-level enzootic RVFV circulation in livestock in Mauritania. Moreover, results indicate that small ruminants can preferably act as sentinels for RVF surveillance.

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