Immunogeno: Protective mechanism for Rift Valley fever in the Democratic Republic of Congo

Rift Valley fever (RVF) is an acute, fever causing viral disease that affects domestic animals and humans. In Democratic Republic of Congo (DRC), this pathology is not well documented. No epidemic of the RVF has not been reported but sera samples collected in six provinces surveyed from 2005 to 2006 revealed 14% of apparent prevalence and, high apparent prevalence (20%) of antibodies against RVF virus was reported in Katanga Province during the same survey; this serological evidence was associated with abortions cases in Cattle (Mulumba et al. 2009). Livestock immunisation is important for control of Rift Valley fever virus (RVFV) epidemics; however immunisation of susceptible domestic animals in endemic countries does not protect animals against the clinical disease but prevents the propagation of virus to human population through reduction of the amplification degree in host animals. The humoral immunity is sufficient for protection for animals as well as for humans. The infection caused by RVFV leads to neutralisation of the immunity of the animal (Barnard 1979).Various immunological studies have been made on the characterisation of immune response during RVFV epidemics but, until now several studies have been concentrated on the response of the innate immune particularly based on signal interferon system than the response of the adaptive immune and cell mediated humoral immune. The available information on the immune response related to RVFV does not seem to provide enough information on various mechanisms of the response immune system.The aim of the study is based on mechanism of immune response system including protective effect of immunisation against RVFV. In addition, epidemiological and molecular studies will be assessed. As a matter of fact, following studies will be conducted:• evaluation of the immunological protection against Rift Valley fever in vaccinated and non- vaccinated cattle using IgG and IgM ELISAs in Katanga Province• assessment of cellular response to Rift Valley fever disease in vaccinated and naturally infected cattle• molecular characterisation of RVFV strains circulating in vaccinated and non vaccinated cattle• assessment of protective effect related to vaccinal strains in cattle, using a longitudinal survey.The studies will be carried out Northern Katanga Province within two areas, one with historyof circulation of RVFV and other without history RVFV circulation.Whole blood, spleen, liver, lymph node will be collected as target tissues from cattle carcasses. In addition, goats and sheeps samples will be collected alongside from each area in order to clarify the disease situation. Serological tests based on the detection of Ig M and Ig G will be used. DIVA tests, LAMP, and IHC techniques will be used. Within previously vaccinated areas in the above mentioned areas and those that are not vaccinated, the collected samples will be analysed using RT-PCR/RT-LAMP.In vitro experimental studies systems will be carried out using animal PMBCs that will be infected with wild type of RVF virus as well as with vaccinal strains, such as clones 13 and MP12 to characterise various cell types such as CD4 T cells, CD8 T cells, B-cells, NK cells and, macrophages will be studied with regard to activation and apoptosis signals on various post – infection days, using flow cytometry. A pool of animals will be vaccinated with the Clone 13 and another with the MP12 to determine the traceability. The monitoring of the immune response will be done through the measurement of immunoglobulin G (Ig G) and immunoglobulin M (Ig M). RT-PCR, spectrophotometer or Facs methods will be used for the dosage of cells T CD4 + and Cell T CD8+.

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Seroprevalence and Virus Activity of Rift Valley Fever in Cattle in Eastern Region of Democratic Republic of the Congo

Journal of Veterinary Medicine ◽

10.1155/2018/4956378 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 5

Author(s):

Tshilenge M. Georges ◽

Masumu Justin ◽

Mbao Victor ◽

Kayembe Jean Marie ◽

Rweyemamu Mark ◽

...

Keyword(s):

Rift Valley ◽

Rift Valley Fever ◽

Democratic Republic ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

Eastern Province ◽

Valley Fever ◽

Republic Of The Congo ◽

South Kivu ◽

North Kivu

Rift Valley fever (RVF) is a zoonotic disease that is characterized by periodic and severe outbreaks in humans and animals. Published information on the occurrence of RVF in domestic animals is very scarce in the Democratic Republic of the Congo (DRC). To assess possible circulation of Rift Valley fever virus (RVFV) in cattle in the eastern province of DRC, 450 sera collected from cattle in North Kivu, South Kivu, and Ituri provinces were analyzed using the enzyme-linked immunosorbent assay (ELISA), for the detection of viral Immunoglobulin (Ig) G and M, and reverse transcriptase polymerase chain reaction (RT-PCR), for detection of viral RVF RNA. A cumulative anti-RVF IgG prevalence of 6.22% (95% CI 4.25–8.97) was recorded from the three provinces sampled. In North Kivu and Ituri provinces the anti-RVF IgG prevalence was 12.67% [95% CI 7.80–19.07] and 6% [95% CI 2.78–11.08], respectively, while all the sera collected from South Kivu province were negative for anti-RVF IgG antibodies. Anti-RVF IgM prevalence of 1.8% was obtained among sampled animals in the three provinces. None of the positive anti-RVF IgM samples (n=8) was positive for viral RVFV RNA using RT-PCR. Our findings suggest that RVFV is widely distributed among cattle in eastern province of DRC particularly in North Kivu and Ituri provinces although the epidemiological factors supporting this virus circulation remain unknown in these areas.

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Rift Valley fever virus in small ruminants in the Democratic Republic of the Congo

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v86i1.1737 ◽

2019 ◽

Vol 86 (1) ◽

Author(s):

Georges M. Tshilenge ◽

Mfumu L.K Mulumba ◽

Gerald Misinzo ◽

Rob Noad ◽

William G. Dundon

Keyword(s):

Rift Valley ◽

Rift Valley Fever ◽

Democratic Republic ◽

Rift Valley Fever Virus ◽

Small Ruminants ◽

Rt Pcr ◽

Recent Infection ◽

Valley Fever ◽

Sheep And Goats ◽

Republic Of The Congo

Rift Valley fever (RVF) is a zoonotic viral disease caused by the RVF phlebovirus (RVFV) that infects a variety of animal species including sheep and goats. Sera (n = 893) collected between 2013 and 2015 from randomly selected indigenous sheep and goats in seven provinces of the Democratic Republic of the Congo (DRC) were tested for the presence of specific immunoglobulin G (IgG) and M (IgM) against RVFV, using two commercially available enzyme-linked immunosorbent assays. The reverse transcription polymerase chain reaction (RT-PCR) was also used to detect RVFV nucleic acid. There was significant variation in true seroprevalence of RVFV for both sheep and goats between the seven provinces investigated. Values ranged from 0.0 (95% confidence interval [CI] 0.0–6.55) to 23.81 (95% CI 12.03–41.76) for goat and 0.0 (95% CI 0.0–7.56) to 37.11 (95% CI 15.48–65.94) for sheep, respectively. One serum (1.85%) out of 54 that tested positive for IgG was found to be IgM-positive. This same sample was also positive by RT-PCR indicating an active or recent infection. These findings report the presence of RVFV in small ruminants in the DRC for the first time and indicate variations in exposure to the virus in different parts of the country.

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Seroprevalence of Rift Valley fever in cattle of smallholder farmers in Kwilu Province in the Democratic Republic of Congo

Tropical Animal Health and Production ◽

10.1007/s11250-019-01978-z ◽

2019 ◽

Vol 51 (8) ◽

pp. 2619-2627 ◽

Cited By ~ 2

Author(s):

Abdel-Amir Dib Halawi ◽

Ngonda Saasa ◽

Boniface Lombe Pongombo ◽

Masahiro Kajihara ◽

Herman Moses Chambaro ◽

...

Keyword(s):

Rift Valley ◽

Rift Valley Fever ◽

Democratic Republic ◽

Democratic Republic Of Congo ◽

Smallholder Farmers ◽

Republic Of Congo ◽

Valley Fever

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Methodological aspects of serosurveillance in resource-poor settings

Veterinary Record Open ◽

10.1136/vetreco-2017-000273 ◽

2018 ◽

Vol 5 (1) ◽

pp. e000273 ◽

Cited By ~ 1

Author(s):

Susanna Sternberg Lewerin ◽

Cecilia Wolff ◽

Charles Masembe ◽

Karl Ståhl ◽

Sofia Boqvist ◽

...

Keyword(s):

Low Income ◽

Rift Valley ◽

Rift Valley Fever ◽

Low Income Countries ◽

Contagious Bovine Pleuropneumonia ◽

Recent Infection ◽

Valley Fever ◽

True Prevalence ◽

Apparent Prevalence ◽

Test Kit

Animal production is important for the agricultural economy in low-income countries, but is threatened by infectious diseases. Serosurveys are conducted for different reasons such as disease detection, risk factor studies, disease monitoring and establishing disease-free status. Most reports on such serosurveys include some discussion about methodological constraints but still, by necessity, rely on serological results for case definition. This study uses a cross-sectional serosurvey for foot-and-mouth disease (FMD), Rift Valley fever (RVF) and contagious bovine pleuropneumonia (CBPP) in cattle in three districts in Western Uganda to illustrate the limitations of this approach, addressing the questions of what flaws can be expected in sampling and diagnostics and how these influence the results. The target was to collect blood samples from 60 cattle herds per district. To reflect the recent infection history of the herd, young animals (two to five years) were prioritised. The farmers were interviewed about management, cattle trade, cattle health and vaccination. Commercial ELISAs were used for serological analyses: for CBPP the IDEXX CBPP Mycoplasma mycoides subspecies mycoides antibody test kit, for RVF the ID Screen Rift Valley Fever competitive ELISA, and for FMD the PrioCHECK FMDV NS. Apparent prevalence, true prevalence and associations with herd characteristics were assessed. The sampling plans could not be entirely fulfilled, nor the number of tests run in the laboratory. There were reactors to all three diseases with an apparent prevalence of approximately 30 per cent for CBPP, 6 per cent for RVF and 7 per cent for FMD. Calculation of true prevalence based on test sensitivity and specificity resulted in a slightly higher prevalence figure for CBPP and lower figures for RVF and FMD. The study illustrates the importance of considering diagnostic test performance when interpreting results from serosurveys, and the challenge of representative sampling and laboratory work in low-income countries.

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A Single-Tube RT-PCR Amplification for Detection of Rift Valley Fever Virus

Research Journal of Medical Sciences ◽

10.3923/rjmsci.2010.146.151 ◽

2010 ◽

Vol 4 (3) ◽

pp. 146-151 ◽

Cited By ~ 2

Author(s):

Reham W. Salim ◽

Khairalla M.S. Khairalla ◽

Awadalkareem A. Eljamal ◽

Abdelrahim E. Karrar ◽

Imadeldin E. Aradaib

Keyword(s):

Rift Valley ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Pcr Amplification ◽

Fever Virus ◽

Rt Pcr ◽

Valley Fever ◽

Single Tube

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Detection of the Northeastern African Rift Valley Fever Virus Lineage During the 2015 Outbreak in Mauritania

Open Forum Infectious Diseases ◽

10.1093/ofid/ofx087 ◽

2017 ◽

Vol 4 (2) ◽

Cited By ~ 6

Author(s):

Ndeye Sakha Bob ◽

Hampâté Bâ ◽

Gamou Fall ◽

Elkhalil Ishagh ◽

Mamadou Y. Diallo ◽

...

Keyword(s):

Rift Valley ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Hemorrhagic Fever ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

West Nile ◽

Valley Fever ◽

Blood Samples ◽

Crimean Congo Hemorrhagic Fever

Abstract Background Rift Valley fever (RVF) is an acute viral anthropozoonosis that causes epizootics and epidemics among livestock population and humans. Multiple emergences and reemergences of the virus have occurred in Mauritania over the last decade. This article describes the outbreak that occurred in 2015 in Mauritania and reports the results of serological and molecular investigations of blood samples collected from suspected RVF patients. Methods An RVF outbreak was reported from 14 September to 26 November 2015 in Mauritania. Overall, 184 suspected cases from different localities were identified by 26 health facilities. Blood samples were collected and tested by enzyme-linked immunosorbent assay (ELISA) and real-time reverse-transcription polymerase chain reaction (RT-PCR) at the Institut Pasteur de Dakar (IPD). Sequencing of partial genomes and phylogenetic analyses were performed on RT-PCR–positive samples. As part of routine surveillance at IPD, samples were also screened for dengue, yellow fever, West Nile, Crimean Congo hemorrhagic fever, Zika, and Chikungunya viruses by ELISA and RT-PCR. Results Of the 184 suspected cases, there were 57 confirmed cases and 12 deaths. Phylogenetic analysis of the sequences indicated an emergence of a virus that originated from Northeastern Africa. Our results show co-circulation of other arboviruses in Mauritania—dengue, Crimean Congo hemorrhagic fever, and West Nile viruses. Conclusion The Northeastern Africa lineage of RVF was responsible for the outbreak in Mauritania in 2015. Co-circulation of multiples arboviruses was detected. This calls for systematic differential diagnosis and highlights the need to strengthen arbovirus surveillance in Africa.

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Preliminary survey of domestic animals of the Sudan for precipitating antibodies to Rift Valley fever virus

Journal of Hygiene ◽

10.1017/s0022172400065207 ◽

1984 ◽

Vol 93 (3) ◽

pp. 629-637 ◽

Cited By ~ 14

Author(s):

M. Eisa

Keyword(s):

Rift Valley ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Domestic Animals ◽

Nile Valley ◽

Preliminary Survey ◽

Serum Samples ◽

Valley Fever ◽

The North ◽

The Rich

SummaryIn a preliminary seroepidemiological survey a total of 780 serum samples derived from various domestic animals of the Sudan were examined for Rift Valley fever (RVF) virus precipitating antibodies. The incidence was approximately 34·3% in sheep, 33·2% in cattle, 22%in goats, 7·9% in camels and 4% in donkeys. The findings indicated that RVF is mainly prevalent in the rich savanna areas of the south as well as the irrigated areas close to the Nile in the north.Circumstantial evidence suggests that the detected antibodies were induced by a long-standing cryptically cycling infection and that resurgence of extensive epizootics is unlikely although limited outbreaks may occur. It is concluded that RVF virus circulates across the country in a south–north range along the Nile Valley with little or no extension to the drier lands to the east and west, and that ruminants are the primary species involved in virus maintenance. These species evidently serve as main amplifiers of infection during epizootics, but whether or not they also serve as sole virus reservoirs in inter-epizootic periods has yet to be determined.

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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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