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Situma S, Nyakarahuka L, Omondi E, Mureithi M, Mweu M, Muturi M, Mwatondo A, Dawa J, Konongoi L, Khamadi S, Clancey E, Lofgren E, Osoro E, Ngere I, Breiman RF, Bakamutumaho B, Muruta A, Gachohi J, Oyola SO, Njenga MK, Singh D. Widening geographic range of Rift Valley fever disease clusters associated with climate change in East Africa. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.17.24307534. [PMID: 38798521 PMCID: PMC11118650 DOI: 10.1101/2024.05.17.24307534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Background Recent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease. We investigated factors associated with the phenomenon by characterizing recent RVF disease events in East Africa. Methods Data on 100 disease events (2008 - 2022) from Kenya, Uganda, and Tanzania were obtained from public databases and institutions, and modeled against possible geo-ecological risk factors of occurrence including altitude, soil type, rainfall/precipitation, temperature, normalized difference vegetation index (NDVI), livestock production system, land-use change, and long-term climatic variations. Decadal climatic variations between 1980-2022 were evaluated for association with the changing disease pattern. Results Of 100 events, 91% were small RVF clusters with a median of one human (IQR, 1-3) and 3 livestock cases (IQR, 2-7). These clusters exhibited minimal human mortality (IQR 0-1), and occurred primarily in highlands (67%), with 35% reported in areas that had never reported RVF disease. Multivariate regression analysis of geo-ecological variables showed a positive correlation between occurrence and increasing temperature and rainfall. A 1oC increase in temperature and 1-unit increase in NDVI, 1-3 months prior were associated with increased RVF incidence rate ratios (IRR) of 1.20 (95% CI 1.1,1.2) and 9.88 (95% CI 0.85, 119.52), respectively. Long-term climatic trends showed significant decadal increase in annual mean temperature (0.12 to 0.3oC/decade, P<0.05), associated with decreasing rainfall in arid and semi-arid lowlands but increasing rainfall trends in highlands (P<0.05). These hotter and wetter highlands showed increasing frequency of RVF clusters, accounting for 76% and 43% in Uganda and Kenya, respectively. Conclusion These findings demonstrate the changing epidemiology of RVF disease. The widening geographic range of disease is associated with climatic variations, with the likely impact of wider dispersal of virus to new areas of endemicity and future epidemics. Key questions What is already known on this topic?: Rift Valley fever is recognized for its association with heavy rainfall, flooding, and El Niño rains in the East African region. A growing body of recent studies has highlighted a shifting landscape of the disease, marked by an expanding geographic range and an increasing number of small RVF clusters.What this study adds: This study challenges previous beliefs about RVF, revealing that it predominantly occurs in small clusters rather than large outbreaks, and its association with El Niño is not as pronounced as previously thought. Over 65% of these clusters are concentrated in the highlands of Kenya and Uganda, with 35% occurring in previously unaffected regions, accompanied by an increase in temperature and total rainfall between 1980 and 2022, along with a rise in the annual number of rainy days. Notably, the observed rainfall increases are particularly significant during the short-rains season (October-December), aligning with a secondary peak in RVF incidence. In contrast, the lowlands of East Africa, where typical RVF epidemics occur, display smaller and more varied trends in annual rainfall.How this study might affect research, practice, or policy: The worldwide consequence of the expanding RVF cluster is the broader dispersion of the virus, leading to the establishment of new regions with virus endemicity. This escalation heightens the risk of more extensive extreme-weather-associated RVF epidemics in the future. Global public health institutions must persist in developing preparedness and response strategies for such scenarios. This involves the creation and approval of human RVF vaccines and therapeutics, coupled with a rapid distribution plan through regional banks.
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Ebogo‐Belobo JT, Kenmoe S, Abanda NN, Bowo‐Ngandji A, Mbaga DS, Magoudjou‐Pekam JN, Kame‐Ngasse GI, Tchatchouang S, Menkem EZ, Okobalemba EA, Noura EA, Meta‐Djomsi D, Maïdadi‐Foudi M, Kenfack‐Zanguim J, Kenfack‐Momo R, Kengne‐Nde C, Esemu SN, Mbacham WF, Sadeuh‐Mba SA, Ndip L, Njouom R. Contemporary epidemiological data of Rift Valley fever virus in humans, mosquitoes and other animal species in Africa: A systematic review and meta-analysis. Vet Med Sci 2023; 9:2309-2328. [PMID: 37548116 PMCID: PMC10508527 DOI: 10.1002/vms3.1238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/29/2023] [Accepted: 07/21/2023] [Indexed: 08/08/2023] Open
Abstract
Rift Valley fever (RVF) is a severe zoonotic mosquito-borne disease that represents an important threat to human and animal health, with major public health and socioeconomic impacts. This disease is endemic throughout many African countries and the Arabian Peninsula. This systematic review with meta-analysis was conducted to determine the RVF prevalence in humans, mosquitoes and other animal species in Africa. The review also provides contemporary data on RVF case fatality rate (CFR) in humans. In this systematic review with meta-analysis, a comprehensive literature search was conducted on the PubMed, Embase, Web of Science and Global Index Medicus databases from January 2000 to June 2022 to identify relevant studies. Pooled CFR and prevalence estimates were calculated using the random-effects model. Subgroup analysis and sensitivity analysis were performed, and the I2 -statistic was used to investigate a potential source of heterogeneity. A total of 205 articles were included in the final analysis. The overall RVF CFR in humans was found to be 27.5% [95% CI = 8.0-52.5]. The overall pooled prevalence was 7.8% [95% CI = 6.2-9.6] in humans and 9.3% [95% CI = 8.1-10.6] in animals, respectively. The RVF prevalence in individual mosquitoes ranged from 0.0% to 25%. Subgroup analysis showed substantial heterogeneity with respect to geographical regions and human categories. The study shows that there is a correspondingly similar prevalence of RVF in human and animals; however, human CFR is much higher than the observed prevalence. The lack of a surveillance programme and the fact that this virus has subclinical circulation in animals and humans could explain these observations. The implementation of a One Health approach for RVF surveillance and control would be of great interest for human and animal health.
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Affiliation(s)
- Jean Thierry Ebogo‐Belobo
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Sebastien Kenmoe
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Ngu Njei Abanda
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
| | - Arnol Bowo‐Ngandji
- Department of MicrobiologyFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Donatien Serge Mbaga
- Department of MicrobiologyFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | | | - Ginette Irma Kame‐Ngasse
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | | | | | | | - Efietngab Atembeh Noura
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | - Dowbiss Meta‐Djomsi
- Research Centre on Emerging and Re‐Emerging DiseasesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | - Martin Maïdadi‐Foudi
- Research Centre on Emerging and Re‐Emerging DiseasesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | | | - Raoul Kenfack‐Momo
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Cyprien Kengne‐Nde
- Epidemiological Surveillance, Evaluation and Research UnitNational AIDS Control CommitteeYaoundéCameroon
| | | | - Wilfred Fon Mbacham
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Serge Alain Sadeuh‐Mba
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
- Maryland Department of AgricultureSalisbury Animal Health LaboratorySalisburyMarylandUSA
| | - Lucy Ndip
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Richard Njouom
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
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Kassam NA, Laswai D, Kulaya N, Kaaya RD, Kajeguka DC, Schmiegelow C, Wang CW, Alifrangis M, Kavishe RA. Human IgG responses to Aedes mosquito salivary peptide Nterm-34kDa and its comparison to Anopheles salivary antigen (gSG6-P1) IgG responses measured among individuals living in Lower Moshi, Tanzania. PLoS One 2022; 17:e0276437. [PMID: 36301860 PMCID: PMC9612500 DOI: 10.1371/journal.pone.0276437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 09/13/2022] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND The level of human exposure to arbovirus vectors, the Aedes mosquitoes, is mainly assessed by entomological methods which are labour intensive, difficult to sustain at a large scale and are affected if transmission and exposure levels are low. Alternatively, serological biomarkers which detect levels of human exposure to mosquito bites may complement the existing epidemiologic tools as they seem cost-effective, simple, rapid, and sensitive. This study explored human IgG responses to an Aedes mosquito salivary gland peptide Nterm-34kDa in Lower Moshi, a highland area with evidence of circulating arboviruses and compared the Aedes IgG responses to Anopheles mosquitoes' salivary antigen (GSG6-P1) IgG responses. METHODS Three cross-sectional surveys were conducted in 2019: during the first dry season in March, at the end of the rainy season in June and during the second dry season in September in five villages located in Lower Moshi. Blood samples were collected from enrolled participants above six months of age (age span: 7 months to 94 years) and analysed for the presence of anti-Nterm-34kDa IgG antibodies. Possible associations between Nterm-34kDa seroprevalence and participants' characteristics were determined. Levels of IgG responses and seroprevalence were correlated and compared to the already measured IgG responses and seroprevalence of Anopheles mosquitoes' salivary antigen, GSG6-P1. RESULTS During the first dry season, Nterm-34kDa seroprevalence was 34.1% and significantly increased at the end of the rainy season to 45.3% (Chi square (χ2) = 6.42 p = 0.011). During the second dry season, the seroprevalence significantly declined to 26.5% (χ2 = 15.12 p<0.001). During the rainy season, seroprevalence was significantly higher among residents of Oria village (adjusted odds ratio (AOR) = 2.86; 95% CI = 1.0-7.8; p = 0.041) compared to Newland. Moreover, during the rainy season, the risk of exposure was significantly lower among individuals aged between 16 and 30 years (AOR = 0.25; 95% CI = 0.1 = 0.9; p = 0.036) compared to individuals aged between 0 and 5 years. There was weak to moderate negative correlation between N-term 34kDa IgG and gSG6-P1 antigens. N-term 34kDa seroprevalence were higher compared to gSG6-P1 seroprevalence. CONCLUSION The findings of this study support that IgG antibody responses towards the Aedes mosquito salivary peptide Nterm-34kDa are detectable among individuals living in lower Moshi and vary with season and geographical area. More individuals are exposed to Aedes mosquito bites than Anopheles mosquito and those exposed to Aedes bites are not necessarily exposed to Anopheles mosquitoes.
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Affiliation(s)
- Nancy A. Kassam
- Kilimanjaro Christian Medical University College (KCMUCo), Moshi, Tanzania
- * E-mail:
| | - Daniel Laswai
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam, Tanzania
| | - Neema Kulaya
- Kilimanjaro Christian Medical University College (KCMUCo), Moshi, Tanzania
| | - Robert D. Kaaya
- Kilimanjaro Christian Medical University College (KCMUCo), Moshi, Tanzania
- Pan-African Malaria Vector Research Consortium, Moshi, Tanzania
| | - Debora C. Kajeguka
- Kilimanjaro Christian Medical University College (KCMUCo), Moshi, Tanzania
| | - Christentze Schmiegelow
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Christian W. Wang
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Michael Alifrangis
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
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Lysholm S, Lindahl JF, Munyeme M, Misinzo G, Mathew C, Alvåsen K, Dautu G, Linde S, Mitternacht L, Olovsson E, Wilén E, Berg M, Wensman JJ. Crossing the Line: Seroprevalence and Risk Factors for Transboundary Animal Diseases Along the Tanzania-Zambia Border. Front Vet Sci 2022; 9:809128. [PMID: 35359681 PMCID: PMC8962627 DOI: 10.3389/fvets.2022.809128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/07/2022] [Indexed: 11/16/2022] Open
Abstract
Transboundary pathogens pose a threat to livelihood security in countries such as Zambia and Tanzania. This study aimed to investigate the seroprevalence of peste des petits ruminants virus (PPRV), foot and mouth disease virus (FMDV), sheep and goat pox virus (SGPV), Rift Valley fever virus (RVFV) and Brucella spp. in sheep and goats along the Tanzania-Zambia border. Another aim was to assess the association between certain predictor variables and seroprevalence, focusing on trade and proximity to an international border, to a town and to the Tanzania-Zambia highway. During September-October 2018, 486 serum samples from small ruminants in Zambia and 491 in Tanzania were collected and analyzed using enzyme-linked immunosorbent assays (ELISA). A questionnaire focused on management strategies was administered to each household. The animal-level seroprevalence in Zambia was 0.21% [95% confidence interval (CI) (0.01–1.14) for PPRV, 1.03% (95% CI 0.33–2.39) for FMDV, 0% (95% CI 0–0.76) for SGPV, 2.26% (95% CI 1.14–4.01) for RVFV and 1.65% (95% CI 0.71–3.22) for Brucella spp.]. In Tanzania, animal-level seroprevalence was 2.85% (95% CI 1.57–4.74) for PPRV, 16.9% (95% CI 13.7–20.5) for FMDV, 0.20% (95% CI 0.01–1.13) for SGPV, 3.26% (95% CI 1.87–5.24) for RVFV and 20.0% (95% CI 14.5–26.5) for Brucella spp. For PPRV (OR 6.83, 95% CI 1.37–34.0, p = 0.019) and FMDV (OR 5.68, 95% CI 1.58–20.3, p = 0.008), herds situated more than 30 km from an international border were more likely to be seropositive, while being located 10–30 km (OR 4.43, 95% CI 1.22–16.1 p = 0.024) from a border was identified as a risk factor for Brucella spp. For FMDV (OR 79.2, 95% CI 4.52–1388.9, p = 0.003), being situated within 30 km from a town was associated with seropositivity. Furthermore, contact with wild ruminants (OR 18.2, 95% CI 1.36–244), and the presence of sheep in the household (OR 5.20, 95% CI 1.00–26.9, p = 0.049), was associated with seropositivity for PPRV, and FMDV. No significant associations between trade or distance to the Tan-Zam highway and seroprevalence were found. We recommend that the impact of trade and proximity to borders, towns and roads should be further evaluated in larger studies, ideally incorporating aspects such as temporal trade fluctuations.
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Affiliation(s)
- Sara Lysholm
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
- *Correspondence: Sara Lysholm
| | - Johanna F. Lindahl
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Biosciences, International Livestock Research Institute, Nairobi, Kenya
| | - Musso Munyeme
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Gerald Misinzo
- SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Coletha Mathew
- Department of Veterinary Anatomy and Pathology, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Karin Alvåsen
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - George Dautu
- Department of Veterinary Services Ministry of Fisheries and Livestock, Central Veterinary Research Institute, Lusaka, Zambia
| | - Siri Linde
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Lydia Mitternacht
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Emelie Olovsson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Elsa Wilén
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Mikael Berg
- Department of Biomedical Science and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jonas J. Wensman
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Department of Epidemiology and Disease Control, National Veterinary Institute, Uppsala, Sweden
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Gerken KN, LaBeaud AD, Mandi H, L’Azou Jackson M, Breugelmans JG, King CH. Paving the way for human vaccination against Rift Valley fever virus: A systematic literature review of RVFV epidemiology from 1999 to 2021. PLoS Negl Trop Dis 2022; 16:e0009852. [PMID: 35073355 PMCID: PMC8812886 DOI: 10.1371/journal.pntd.0009852] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 02/03/2022] [Accepted: 12/22/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Rift Valley fever virus (RVFV) is a lethal threat to humans and livestock in many parts of Africa, the Arabian Peninsula, and the Indian Ocean. This systematic review's objective was to consolidate understanding of RVFV epidemiology during 1999-2021 and highlight knowledge gaps relevant to plans for human vaccine trials. METHODOLOGY/PRINCIPAL FINDINGS The review is registered with PROSPERO (CRD42020221622). Reports of RVFV infection or exposure among humans, animals, and/or vectors in Africa, the Arabian Peninsula, and the Indian Ocean during the period January 1999 to June 2021 were eligible for inclusion. Online databases were searched for publications, and supplemental materials were recovered from official reports and research colleagues. Exposures were classified into five groups: 1) acute human RVF cases, 2) acute animal cases, 3) human RVFV sero-surveys, 4) animal sero-surveys, and 5) arthropod infections. Human risk factors, circulating RVFV lineages, and surveillance methods were also tabulated. In meta-analysis of risks, summary odds ratios were computed using random-effects modeling. 1104 unique human or animal RVFV transmission events were reported in 39 countries during 1999-2021. Outbreaks among humans or animals occurred at rates of 5.8/year and 12.4/year, respectively, with Mauritania, Madagascar, Kenya, South Africa, and Sudan having the most human outbreak years. Men had greater odds of RVFV infection than women, and animal contact, butchering, milking, and handling aborted material were significantly associated with greater odds of exposure. Animal infection risk was linked to location, proximity to water, and exposure to other herds or wildlife. RVFV was detected in a variety of mosquito vectors during interepidemic periods, confirming ongoing transmission. CONCLUSIONS/SIGNIFICANCE With broad variability in surveillance, case finding, survey design, and RVFV case confirmation, combined with uncertainty about populations-at-risk, there were inconsistent results from location to location. However, it was evident that RVFV transmission is expanding its range and frequency. Gaps assessment indicated the need to harmonize human and animal surveillance and improve diagnostics and genotyping. Given the frequency of RVFV outbreaks, human vaccination has strong potential to mitigate the impact of this now widely endemic disease.
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Affiliation(s)
- Keli N. Gerken
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - A. Desirée LaBeaud
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Henshaw Mandi
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | | | | | - Charles H. King
- Center for Global Health and Diseases, Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
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Nyangau PN, Nzuma JM, Irungu P, Kassie M. Evaluating livestock farmers knowledge, beliefs, and management of arboviral diseases in Kenya: A multivariate fractional probit approach. PLoS Negl Trop Dis 2021; 15:e0009786. [PMID: 34529687 PMCID: PMC8478187 DOI: 10.1371/journal.pntd.0009786] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 09/28/2021] [Accepted: 09/02/2021] [Indexed: 12/05/2022] Open
Abstract
Globally, arthropod-borne virus (arbovirus) infections continue to pose substantial threats to public health and economic development, especially in developing countries. In Kenya, although arboviral diseases (ADs) are largely endemic, little is known about the factors influencing livestock farmers’ knowledge, beliefs, and management (KBM) of the three major ADs: Rift Valley fever (RVF), dengue fever and chikungunya fever. This study evaluates the drivers of livestock farmers’ KBM of ADs from a sample of 629 respondents selected using a three-stage sampling procedure in Kenya’s three hotspot counties of Baringo, Kwale, and Kilifi. A multivariate fractional probit model was used to assess the factors influencing the intensity of KBM. Only a quarter of the farmers had any knowledge of ADs while over four-fifths of them could not manage any of the three diseases. Access to information (experience and awareness), income, education, religion, and distance to a health facility considerably influenced the intensity of farmers’ KBM of ADs in Kenya. Thus, initiatives geared towards improving access to information through massive awareness campaigns are necessary to mitigate behavioral barriers in ADs management among rural communities in Kenya. Arboviral infection in humans and animals is on the rise globally due to expansion of vector habitats. Despite the economic and social impact of diseases caused by arboviral infection such as chikungunya, dengue, and Rift Valley fever, little is known in terms of community knowledge, beliefs, and management. Evaluating community knowledge, beliefs, and management practices of arboviral diseases is important for better policy guidance and public health investment. We conducted a survey in Kenya’s three hotspot counties of Baringo, Kwale, and Kilifi to understand the factors influencing knowledge, beliefs, and management of arboviral diseases. We found low levels of knowledge and poor managerial skills of arboviral diseases that were largely driven by access to information and asset ownership. Thus, community sensitization through improved access to information is important in increasing awareness and increase the management of arboviral diseases among rural communities in Kenya and other sub-Saharan African countries.
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Affiliation(s)
- Paul Nyamweya Nyangau
- Department of Agricultural Economics, Faculty of Agriculture, University of Nairobi, Nairobi, Kenya
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- * E-mail:
| | - Jonathan Makau Nzuma
- Department of Agricultural Economics, Faculty of Agriculture, University of Nairobi, Nairobi, Kenya
| | - Patrick Irungu
- Department of Agricultural Economics, Faculty of Agriculture, University of Nairobi, Nairobi, Kenya
| | - Menale Kassie
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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Kumalija MS, Chilongola JO, Budodo RM, Horumpende PG, Mkumbaye SI, Vianney JM, Mwakapuja RS, Mmbaga BT. Detection of Rift Valley Fever virus inter-epidemic activity in Kilimanjaro Region, North Eastern Tanzania. Glob Health Action 2021; 14:1957554. [PMID: 34415237 PMCID: PMC8381910 DOI: 10.1080/16549716.2021.1957554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Background Rift Valley Fever virus (RVFV) is a zoonotic arbovirus of public health impact infecting livestock, wildlife, and humans mainly in Africa and other parts of the world. Despite its public health importance, mechanisms of RVFV maintenance during interepidemic periods (IEPS) remain unclear. Objective We aimed to examine comparatively exposure to RVFV between humans and goats and RVFV infection between humans, goats and mosquitoes. Methods A cross sectional study was performed in the Lower Moshi area of the Kilimanjaro region from March to June 2020. RVFV exposure was determined by detecting IgG/IgM to RVFV using a competitive enzyme linked immunosorbent assay whereas infection was determined by real time quantitative polymerase chain reaction (RT-qPCR) assay. Results Results show that the male gender was related to RVFV seropositivity (χ2 = 5.351; p=0.030). Being 50 years and above was related to seropositivity (χ2 =14.430; p=0.006) whereas bed net use, larger numbers of persons living in the same house (>7 persons) and RVFV seropositivity in goats were related to higher seropositivity to RVFV among humans χ2 =6.003; p=0.021, χ2 =23.213; p < 0.001 and χ2 =27.053; p < 0.001), respectively. By the use of RT-qPCR, goats exhibited the highest RVFV infection rate of 4.1%, followed by humans (2.6%), Ae. aegypti (2.3%), and Cx. pipiens complex(1.5%). Likewise, a higher proportion of goats (23.3%) were RVFV seropositive as compared with humans (13.2%). Conclusion Our findings suggest the Lower Moshi area as a potential hotspot for Rift Valley Fever (RVF), posing the danger of being a source of RVFV spread to other areas. Goats had the highest infection rate, suggesting goats as important hosts for virus maintenance during IEPs. We recommend the implementation of strategies that will warrant active RVF surveillance through the identification of RVF hotspots for targeted control of the disease.
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Affiliation(s)
- Medard S Kumalija
- Department of Global Health and Biomedical Sciences, Nelson Mandela Institution of Science and Technology, Arusha, Tanzania
| | - Jaffu O Chilongola
- Department of Medical Biochemistry and Molecular Biology, Kilimanjaro Christian Medical University College, Moshi Tanzania.,Department of Clinical Trials, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Rule M Budodo
- Department of Clinical Trials, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Pius G Horumpende
- Department of Public Health and Research, Lugalo Military College of Medical Sciences, Dar Es Salaam, Tanzania
| | - Sixbert I Mkumbaye
- Department of Clinical Trials, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - John-Mary Vianney
- Department of Global Health and Biomedical Sciences, Nelson Mandela Institution of Science and Technology, Arusha, Tanzania
| | - Richard S Mwakapuja
- Department of Bacterial Vaccines, Tanzania Veterinary Laboratory Agency (TVLA), Kibaha, Tanzania
| | - Blandina T Mmbaga
- Department of Clinical Trials, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
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Budodo RM, Horumpende PG, Mkumbaye SI, Mmbaga BT, Mwakapuja RS, Chilongola JO. Serological evidence of exposure to Rift Valley, Dengue and Chikungunya Viruses among agropastoral communities in Manyara and Morogoro regions in Tanzania: A community survey. PLoS Negl Trop Dis 2020; 14:e0008061. [PMID: 32687540 PMCID: PMC7402518 DOI: 10.1371/journal.pntd.0008061] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 08/04/2020] [Accepted: 06/11/2020] [Indexed: 11/19/2022] Open
Abstract
Tanzania has recently experienced outbreaks of dengue in two coastal regions of Dar es Salaam and Tanga. Chikungunya and Rift Valley Fever outbreaks have also been recorded in the past decade. Little is known on the burden of the arboviral disease causing viruses (Dengue, Rift Valley and Chikungunya) endemically in the inter-epidemic periods. We aimed at determining the prevalence of the dengue, rift valley and chikungunya among humans in two geo ecologically distinct sites. The community-based cross-sectional study was conducted in Magugu in Manyara region and Wami-Dakawa in Morogoro region in Tanzania. Venous blood was collected from participants of all age groups, serum prepared from samples and subjected to ELISA tests for RVFV IgG/IgM, DENV IgG/IgM, and CHIKV IgM/IgG. Samples that were positive for IgM ELISA tests were subjected to a quantitative RT PCR for each virus. A structured questionnaire was used to collect socio-demographic information. Data analysis was performed by using SPSSv22. A total of 191 individuals from both sites participated in the study. Only one individual was CHIKV seropositive in Magugu, but none was seropositive or positive for either RVFV or DENV. Of the 122 individuals from Wami-Dakawa site, 16.39% (n = 20) had recent exposure to RVFV while 9.83% (n = 12) were seropositive for CHIKV. All samples were negative by RVFV and CHIKV qPCR. Neither infection nor exposure to DENV was observed in participants from both sites. Being more than 5 in a household, having no formal education and having recently travelled to an urban area were risk factors associated with RVFV and CHIKV seropositivity. We report a considerable exposure to RVFV and CHIKV among Wami-Dakawa residents during the dry season and an absence of exposure of the viruses among humans in Magugu site. In both sites, neither DENV exposure nor infection was detected.
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Affiliation(s)
- Rule M. Budodo
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Pius G. Horumpende
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
- Department of Public Health and Research, Lugalo Military College of Medical Sciences (MCMS) and General Military Hospital (GMH), Dar es Salaam, Tanzania
| | - Sixbert I. Mkumbaye
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
- Department of Medical Biochemistry and Molecular Biology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Blandina T. Mmbaga
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
- Directorate of Research and Consultancies, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | | | - Jaffu O. Chilongola
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
- Department of Medical Biochemistry and Molecular Biology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
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9
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Chaters GL, Johnson PCD, Cleaveland S, Crispell J, de Glanville WA, Doherty T, Matthews L, Mohr S, Nyasebwa OM, Rossi G, Salvador LCM, Swai E, Kao RR. Analysing livestock network data for infectious disease control: an argument for routine data collection in emerging economies. Philos Trans R Soc Lond B Biol Sci 2020; 374:20180264. [PMID: 31104601 DOI: 10.1098/rstb.2018.0264] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Livestock movements are an important mechanism of infectious disease transmission. Where these are well recorded, network analysis tools have been used to successfully identify system properties, highlight vulnerabilities to transmission, and inform targeted surveillance and control. Here we highlight the main uses of network properties in understanding livestock disease epidemiology and discuss statistical approaches to infer network characteristics from biased or fragmented datasets. We use a 'hurdle model' approach that predicts (i) the probability of movement and (ii) the number of livestock moved to generate synthetic 'complete' networks of movements between administrative wards, exploiting routinely collected government movement permit data from northern Tanzania. We demonstrate that this model captures a significant amount of the observed variation. Combining the cattle movement network with a spatial between-ward contact layer, we create a multiplex, over which we simulated the spread of 'fast' ( R0 = 3) and 'slow' ( R0 = 1.5) pathogens, and assess the effects of random versus targeted disease control interventions (vaccination and movement ban). The targeted interventions substantially outperform those randomly implemented for both fast and slow pathogens. Our findings provide motivation to encourage routine collection and centralization of movement data to construct representative networks. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'. This theme issue is linked with the earlier issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'.
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Affiliation(s)
- G L Chaters
- 1 Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow , Glasgow G12 8QQ , UK
| | - P C D Johnson
- 1 Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow , Glasgow G12 8QQ , UK
| | - S Cleaveland
- 1 Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow , Glasgow G12 8QQ , UK
| | - J Crispell
- 2 School of Veterinary Medicine, University College Dublin , Dublin , Ireland
| | - W A de Glanville
- 1 Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow , Glasgow G12 8QQ , UK
| | - T Doherty
- 3 Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh , Easter Bush Campus, Midlothian EH25 9RG , UK
| | - L Matthews
- 1 Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow , Glasgow G12 8QQ , UK
| | - S Mohr
- 1 Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow , Glasgow G12 8QQ , UK
| | - O M Nyasebwa
- 6 Department of Veterinary Services, Ministry of Livestock and Fisheries, Nelson Mandela Road , Dar Es Salaam , Tanzania
| | - G Rossi
- 3 Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh , Easter Bush Campus, Midlothian EH25 9RG , UK
| | - L C M Salvador
- 3 Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh , Easter Bush Campus, Midlothian EH25 9RG , UK.,4 Department of Infectious Diseases, University of Georgia , Athens, GA 30602 , USA.,5 Institute of Bioinformatics, University of Georgia , Athens, GA 30602 , USA
| | - E Swai
- 6 Department of Veterinary Services, Ministry of Livestock and Fisheries, Nelson Mandela Road , Dar Es Salaam , Tanzania
| | - R R Kao
- 3 Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh , Easter Bush Campus, Midlothian EH25 9RG , UK
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10
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Shoemaker TR, Nyakarahuka L, Balinandi S, Ojwang J, Tumusiime A, Mulei S, Kyondo J, Lubwama B, Sekamatte M, Namutebi A, Tusiime P, Monje F, Mayanja M, Ssendagire S, Dahlke M, Kyazze S, Wetaka M, Makumbi I, Borchert J, Zufan S, Patel K, Whitmer S, Brown S, Davis WG, Klena JD, Nichol ST, Rollin PE, Lutwama J. First Laboratory-Confirmed Outbreak of Human and Animal Rift Valley Fever Virus in Uganda in 48 Years. Am J Trop Med Hyg 2020; 100:659-671. [PMID: 30675833 PMCID: PMC6402942 DOI: 10.4269/ajtmh.18-0732] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In March 2016, an outbreak of Rift Valley fever (RVF) was identified in Kabale district, southwestern Uganda. A comprehensive outbreak investigation was initiated, including human, livestock, and mosquito vector investigations. Overall, four cases of acute, nonfatal human disease were identified, three by RVF virus (RVFV) reverse transcriptase polymerase chain reaction (RT-PCR), and one by IgM and IgG serology. Investigations of cattle, sheep, and goat samples from homes and villages of confirmed and probable RVF cases and the Kabale central abattoir found that eight of 83 (10%) animals were positive for RVFV by IgG serology; one goat from the home of a confirmed case tested positive by RT-PCR. Whole genome sequencing from three clinical specimens was performed and phylogenetic analysis inferred the relatedness of 2016 RVFV with the 2006–2007 Kenya-2 clade, suggesting previous introduction of RVFV into southwestern Uganda. An entomological survey identified three of 298 pools (1%) of Aedes and Coquillettidia species that were RVFV positive by RT-PCR. This was the first identification of RVFV in Uganda in 48 years and the 10th independent viral hemorrhagic fever outbreak to be confirmed in Uganda since 2010.
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Affiliation(s)
- Trevor R Shoemaker
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia.,Viral Special Pathogens Branch, Centers for Disease Control and Prevention-Uganda, Entebbe, Uganda
| | - Luke Nyakarahuka
- Department of Biosecurity, Ecosystems and Veterinary Public Health, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda.,Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Stephen Balinandi
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention-Uganda, Entebbe, Uganda
| | - Joseph Ojwang
- Global Health Security Unit, Centers for Disease Control and Prevention-Uganda, Kampala, Uganda
| | - Alex Tumusiime
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention-Uganda, Entebbe, Uganda
| | - Sophia Mulei
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Jackson Kyondo
- Department of Biosecurity, Ecosystems and Veterinary Public Health, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | | | | | | | | | - Fred Monje
- Ministry of Agriculture, Animal Industry and Fisheries, Kampala, Uganda
| | - Martin Mayanja
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | | | - Melissa Dahlke
- Public Health Emergency Operations Centre, Ministry of Health, Kampala, Uganda
| | - Simon Kyazze
- Public Health Emergency Operations Centre, Ministry of Health, Kampala, Uganda
| | - Milton Wetaka
- Public Health Emergency Operations Centre, Ministry of Health, Kampala, Uganda
| | - Issa Makumbi
- Public Health Emergency Operations Centre, Ministry of Health, Kampala, Uganda
| | - Jeff Borchert
- Global Health Security Unit, Centers for Disease Control and Prevention-Uganda, Kampala, Uganda
| | - Sara Zufan
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Ketan Patel
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Shannon Whitmer
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Shelley Brown
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - William G Davis
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - John D Klena
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Stuart T Nichol
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Pierre E Rollin
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Julius Lutwama
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
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11
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Matiko MK, Salekwa LP, Kasanga CJ, Kimera SI, Evander M, Nyangi WP. Serological evidence of inter-epizootic/inter-epidemic circulation of Rift Valley fever virus in domestic cattle in Kyela and Morogoro, Tanzania. PLoS Negl Trop Dis 2018; 12:e0006931. [PMID: 30418975 PMCID: PMC6258417 DOI: 10.1371/journal.pntd.0006931] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 11/26/2018] [Accepted: 10/17/2018] [Indexed: 11/19/2022] Open
Abstract
Background Tanzania is among the Rift Valley fever (RVF) epizootic/endemic countries in sub Saharan Africa, where RVF disease outbreaks occur within a range of 3 to 17-year intervals. Detection of Rift Valley fever virus (RVFV) antibodies in animals in regions with no previous history of outbreaks raises the question of whether the disease is overlooked due to lack-of effective surveillance systems, or if there are strains of RVFV with low pathogenicity. Furthermore, which vertebrate hosts are involved in the inter-epidemic and inter-epizootic maintenance of RVFV? In our study region, the Kyela and Morogoro districts in Tanzania, no previous RVF outbreaks have been reported. Methodology The study was conducted from June 2014 to October 2015 in the Kyela and Morogoro districts, Tanzania. Samples (n = 356) were retrieved from both the local breed of zebu cattle (Bos indicus) and Bos indicus/Bos Taurus cross breed. RVFV antibodies were analyzed by two enzyme-linked immunosorbent assay (ELISA) approaches. Initially, samples were analyzed by a RVFV multi-species competition ELISA (cELISA), which detected both RVFV IgG and IgM antibodies. All serum samples that were positive with the cELISA method were specifically analysed for the presence of RVFV IgM antibodies to trace recent infection. A plaque reduction neutralization assay (PRNT80) was performed to determine presence of RVFV neutralizing antibodies in all cELISA positive samples. Findings Overall RVFV seroprevalence rate in cattle by cELISA in both districts was 29.2% (104 of 356) with seroprevalence rates of 33% (47/147) in the Kyela district and 27% (57/209) in the Morogoro district. In total, 8.4% (30/356) of all cattle sampled had RVFV IgM antibodies, indicating current disease transmission. When segregated by districts, the IgM antibody seroprevalence was 2.0% (3/147) and 12.9% (27/209) in Kyela and Morogoro districts respectively. When the 104 cELISA positive samples were analyzed by PRNT80 to confirm that RVFV-specific antibodies were present, the majority (89%, 93/104) had RVFV neutralising antibodies. Conclusion The results provided evidence of widespread prevalence of RVFV antibody among cattle during an inter-epizootic/inter-epidemic period in Tanzania in regions with no previous history of outbreaks. There is a need for further investigations of RVFV maintenance and transmission in vertebrates and vectors during the long inter-epizootic/inter-epidemic periods. The RVFV maintenance between inter-epizootic/inter-epidemic periods is not fully understood, despite the widely hypothesized belief of maintenance via transovarially infected Aedes mosquito eggs. Increasing serological evidence however, suggests that there could be continuous virus circulation throughout these periods in domestic ruminants, wild animals and humans both in areas with and without known history of RVF outbreaks. In some countries, RVFV antibodies have been demonstrated in livestock raised in areas where no clinical disease has ever been reported. However, in Tanzania, RVFV antibodies in livestock have been demonstrated only in areas with history of RVF outbreaks, raising the question of whether the disease is not present, is overlooked due to lack of effective surveillance systems, or whether there are strains of RVFV with low pathogenicity that do not cause detectable clinical cases in non-outbreak areas. We report here inter-epizootic/inter-epidemic RVFV antibody prevalence in non-vaccinated cattle from areas with no previous RVF outbreak in Tanzania and demonstrate recent virus circulation by detection of IgM antibodies. The differences in RVFV seroprevalence in different study locations suggest local factors that favour the virus amplification and transmission within those areas.
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Affiliation(s)
- Mirende Kichuki Matiko
- Department of Veterinary Surgery and Theriogenology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
- * E-mail:
| | - Linda Peniel Salekwa
- Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Christopher Jacob Kasanga
- Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Sharadhuli Idd Kimera
- Department of Veterinary Medicine and Public Health, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Magnus Evander
- Department of Clinical Microbiology, Division of Virology, Umeå University, Umeå, Sweden
| | - Wambura Philemon Nyangi
- Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
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12
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Clark MHA, Warimwe GM, Di Nardo A, Lyons NA, Gubbins S. Systematic literature review of Rift Valley fever virus seroprevalence in livestock, wildlife and humans in Africa from 1968 to 2016. PLoS Negl Trop Dis 2018; 12:e0006627. [PMID: 30036382 PMCID: PMC6072204 DOI: 10.1371/journal.pntd.0006627] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 08/02/2018] [Accepted: 06/22/2018] [Indexed: 02/03/2023] Open
Abstract
Background Rift Valley fever virus (RVFV) is a zoonotic arbovirus that causes severe disease in livestock and humans. The virus has caused recurrent outbreaks in Africa and the Arabian Peninsula since its discovery in 1931. This review sought to evaluate RVFV seroprevalence across the African continent in livestock, wildlife and humans in order to understand the spatio-temporal distribution of RVFV seroprevalence and to identify knowledge gaps and areas requiring further research. Risk factors associated with seropositivity were identified and study designs evaluated to understand the validity of their results. Methodology The Preferred Reporting of Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to produce a protocol to systematically search for RVFV seroprevalence studies in PubMed and Web of Science databases. The Strengthening the Reporting of Observational studies in Epidemiology (STROBE) statement guided the evaluation of study design and analyses. Principal findings A total of 174 RVFV seroprevalence studies in 126 articles fulfilled the inclusion criteria. RVFV seroprevalence was recorded in 31 African countries from 1968 to 2016 and varied by time, species and country. RVFV seroprevalence articles including either livestock and humans or livestock and wildlife seroprevalence records were limited in number (8/126). No articles considered wildlife, livestock and human seroprevalence concurrently, nor wildlife and humans alone. Many studies did not account for study design bias or the sensitivity and specificity of diagnostic tests. Conclusions Future research should focus on conducting seroprevalence studies at the wildlife, livestock and human interface to better understand the nature of cross-species transmission of RVFV. Reporting should be more transparent and biases accounted for in future seroprevalence research to understand the true burden of disease on the African continent. Rift Valley fever virus (RVFV) is a vector-borne virus that infects wildlife and livestock, and can subsequently spread to humans. Due to the nature of the disease it has the potential to cause substantial economic and public health impacts. Rift Valley Fever (RVF) has been identified in Africa and the Arabian Peninsula, but has the potential to spread more widely. This systematic review assessed the distribution of RVF in livestock and humans in Africa by collating all the relevant studies we could find, extracting the data and critically evaluating them. Understanding when and where RVF has occurred in Africa and why some animals and humans get disease helps target control strategies and, in particular, those that reduce spread from livestock to humans. Furthermore, by evaluating past studies we can ensure that future ones are more robust and reproducible, so they can help us better understand the disease.
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Affiliation(s)
- Madeleine H. A. Clark
- Transmission Biology Group, The Pirbright Institute, Pirbright, Woking, United Kingdom
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - George M. Warimwe
- Biosciences Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Antonello Di Nardo
- Vesicular Disease Reference Laboratories, The Pirbright Institute, Pirbright, Woking, United Kingdom
| | - Nicholas A. Lyons
- Vesicular Disease Reference Laboratories, The Pirbright Institute, Pirbright, Woking, United Kingdom
| | - Simon Gubbins
- Transmission Biology Group, The Pirbright Institute, Pirbright, Woking, United Kingdom
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13
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Sternberg Lewerin S, Wolff C, Masembe C, Ståhl K, Boqvist S, Franko MA. Methodological aspects of serosurveillance in resource-poor settings. Vet Rec Open 2018; 5:e000273. [PMID: 29682293 PMCID: PMC5905835 DOI: 10.1136/vetreco-2017-000273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/13/2018] [Accepted: 03/20/2018] [Indexed: 11/09/2022] Open
Abstract
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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Affiliation(s)
- Susanna Sternberg Lewerin
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Cecilia Wolff
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Charles Masembe
- College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Karl Ståhl
- Department of Epidemiology and Disease Control, National Veterinary Institute SVA, Uppsala, Sweden
| | - Sofia Boqvist
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Mikael Andersson Franko
- Department of Applied Statistics and Mathematics, Swedish University of Agricultural Sciences, Uppsala, Sweden
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14
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A diagnostic and epidemiologic investigation of acute febrile illness (AFI) in Kilombero, Tanzania. PLoS One 2017; 12:e0189712. [PMID: 29287070 PMCID: PMC5747442 DOI: 10.1371/journal.pone.0189712] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/30/2017] [Indexed: 12/20/2022] Open
Abstract
Introduction In low-resource settings, empiric case management of febrile illness is routine as a result of limited access to laboratory diagnostics. The use of comprehensive fever syndromic surveillance, with enhanced clinical microbiology, advanced diagnostics and more robust epidemiologic investigation, could enable healthcare providers to offer a differential diagnosis of fever syndrome and more appropriate care and treatment. Methods We conducted a year-long exploratory study of fever syndrome among patients ≥ 1 year if age, presenting to clinical settings with an axillary temperature of ≥37.5°C and symptomatic onset of ≤5 days. Blood and naso-pharyngeal/oral-pharyngeal (NP/OP) specimens were collected and analyzed, respectively, using AFI and respiratory TaqMan Array Cards (TAC) for multi-pathogen detection of 57 potential causative agents. Furthermore, we examined numerous epidemiologic correlates of febrile illness, and conducted demographic, clinical, and behavioral domain-specific multivariate regression to statistically establish associations with agent detection. Results From 15 September 2014–13 September 2015, 1007 febrile patients were enrolled, and 997 contributed an epidemiologic survey, including: 14% (n = 139) 1<5yrs, 19% (n = 186) 5-14yrs, and 67% (n = 672) ≥15yrs. AFI TAC and respiratory TAC were performed on 842 whole blood specimens and 385 NP/OP specimens, respectively. Of the 57 agents surveyed, Plasmodium was the most common agent detected. AFI TAC detected nucleic acid for one or more of seven microbial agents in 49% of AFI blood samples, including: Plasmodium (47%), Leptospira (3%), Bartonella (1%), Salmonella enterica (1%), Coxiella burnetii (1%), Rickettsia (1%), and West Nile virus (1%). Respiratory TAC detected nucleic acid for 24 different microbial agents, including 12 viruses and 12 bacteria. The most common agents detected among our surveyed population were: Haemophilus influenzae (67%), Streptococcus pneumoniae (55%), Moraxella catarrhalis (39%), Staphylococcus aureus (37%), Pseudomonas aeruginosa (36%), Human Rhinovirus (25%), influenza A (24%), Klebsiella pneumoniae (14%), Enterovirus (15%) and group A Streptococcus (12%). Our epidemiologic investigation demonstrated both age and symptomatic presentation to be associated with a number of detected agents, including, but not limited to, influenza A and Plasmodium. Linear regression of fully-adjusted mean cycle threshold (Ct) values for Plasmodium also identified statistically significant lower mean Ct values for older children (20.8), patients presenting with severe fever (21.1) and headache (21.5), as well as patients admitted for in-patient care and treatment (22.4). Conclusions This study is the first to employ two syndromic TaqMan Array Cards for the simultaneous survey of 57 different organisms to better characterize the type and prevalence of detected agents among febrile patients. Additionally, we provide an analysis of the association between adjusted mean Ct values for Plasmodium and key clinical and demographic variables, which may further inform clinical decision-making based upon intensity of infection, as observed across endemic settings of sub-Saharan Africa.
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15
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Torsson E, Berg M, Misinzo G, Herbe I, Kgotlele T, Päärni M, Roos N, Blomström AL, Ståhl K, Johansson Wensman J. Seroprevalence and risk factors for peste des petits ruminants and selected differential diagnosis in sheep and goats in Tanzania. Infect Ecol Epidemiol 2017; 7:1368336. [PMID: 29081918 PMCID: PMC5645728 DOI: 10.1080/20008686.2017.1368336] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 08/04/2017] [Indexed: 12/18/2022] Open
Abstract
Introduction: Livestock husbandry is critical for food security and poverty reduction in a low-income country like Tanzania. Infectious disease is one of the major constraints reducing the productivity in this sector. Peste des petits ruminants (PPR) is one of the most important diseases affecting small ruminants, but other infectious diseases may also be present. Objective: The objective of this study was to determine the seroprevalence and risk factors for exposure to PPR, contagious caprine pleuropneumonia (CCPP), foot-and-mouth disease (FMD), bluetongue (BT), and bovine viral diarrhoea (BVD) in sheep and goats in Tanzania. Methods: Serum samples were collected in 2014 and 2015, and analysed using enzyme-linked immunosorbent assays to detect antibodies to the five pathogens. Results and discussion: This is the first description of seroprevalence of FMD and BT among small ruminants in Tanzania. Risk factor analysis identified sex (female) (OR for 2014: PPR: 2.49, CCPP: 3.11, FMD: 2.98, BT: 12.4, OR for 2015: PPR: 14.1, CCPP: 1.10, FMD: 2.67, BT: 1.90, BVD: 4.73) and increasing age (>2 years) (OR for 2014: PPR: 14.9, CCPP: 2.34, FMD: 7.52, BT: 126, OR for 2015: PPR: 8.13, CCPP: 1.11, FMD: 2.98, BT: 7.83, BVD: 4.74) as risk factors for exposure to these diseases.
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Affiliation(s)
- Emeli Torsson
- Department of Biomedical Sciences & Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.,Department of Veterinary Microbiology and Parasitology, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Mikael Berg
- Department of Biomedical Sciences & Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Gerald Misinzo
- Department of Veterinary Microbiology and Parasitology, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Ida Herbe
- Department of Veterinary Microbiology and Parasitology, Sokoine University of Agriculture, Morogoro, Tanzania.,Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Tebogo Kgotlele
- Department of Veterinary Microbiology and Parasitology, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Malin Päärni
- Department of Veterinary Microbiology and Parasitology, Sokoine University of Agriculture, Morogoro, Tanzania.,Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Nils Roos
- Department of Biomedical Sciences & Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.,Department of Veterinary Microbiology and Parasitology, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Anne-Lie Blomström
- Department of Biomedical Sciences & Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Karl Ståhl
- National Veterinary Institute, Department of Disease Control and Epidemiology, Uppsala, Sweden
| | - Jonas Johansson Wensman
- Department of Veterinary Microbiology and Parasitology, Sokoine University of Agriculture, Morogoro, Tanzania.,Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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16
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Gür S, Kale M, Erol N, Yapici O, Mamak N, Yavru S. The first serological evidence for Rift Valley fever infection in the camel, goitered gazelle and Anatolian water buffaloes in Turkey. Trop Anim Health Prod 2017; 49:1531-1535. [PMID: 28861841 DOI: 10.1007/s11250-017-1359-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 07/05/2017] [Indexed: 11/30/2022]
Abstract
Rift valley fever (RVF), a vector-borne zoonotic disease, is caused by a phlebovirus (family Bunyaviridae). The virus was initially characterized approximately 80 years ago in Kenya and disseminated to many countries in the continental Africa, Saudi Arabia, and Yemen. The infection has not been reported in Turkey. In this study, blood serum samples collected from camel (Camelus dromedairus), goitered gazelle (Gazella subgutturosa subgutturosa), and buffaloes (Bubalus bubalis linneaus) from 2000 to 2006 were investigated for RVF using C-ELISA. Camel samples (n = 72) were obtained from private small enterprises in Aydın province in theAegean region. Gazella samples (82) were taken from the biggest captive gazelle herd in Şanlıurfa province in the southeast Anatolia. Buffalo samples were collected mostly from small private family type farms in Afyon (168), Amasya (80), Samsun (69), Ankara (35), Sivas (21), Tokat (19), Konya (10), and Elazığ (8) provinces in the central, north, west, and east Anatolia. All of the gazella samples were negative; whereas, one of the 71 camel samples (1.3%) was positive for RVF-specific antibodies. Buffalos from Sivas, Tokat, Konya, and Elazığ provinces were negative. However, 35 of the 410 samples (8.5%) from rural areas in the following four provinces were positive: Amasya (12/80, 15%), Ankara (5/35, 14.2%), Samsun (8/69, 11.5%), and Afyon (10/168, 5.9%). To our knowledge, this is the first report of presence of RVF infection in Turkey.
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Affiliation(s)
- Sibel Gür
- Department of Virology, Faculty of Veterinary Medicine, AfyonKocatepe University, 03200, Afyonkarahisar, Turkey.
| | - Mehmet Kale
- Department of Virology, Faculty of Veterinary Medicine, Mehmet AkifErsoy University, 15030, Burdur, Turkey
| | - Nural Erol
- Department of Virology, Faculty of Veterinary Medicine, Adnan Menderes University, 09016, Aydın, Turkey
| | - Orhan Yapici
- Department of Virology, Faculty of Veterinary Medicine, Selcuk University, 42003, Konya, Turkey
| | - Nuri Mamak
- Department of Internal Diseases, Faculty of Veterinary Medicine, Mehmet AkifErsoy University, 15030, Burdur, Turkey
| | - Sibel Yavru
- Department of Virology, Faculty of Veterinary Medicine, Selcuk University, 42003, Konya, Turkey
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