Seroprevalence Of Rift Valley Fever Research Articles

Seroprevalence and Geographical Distribution of Rift Valley Fever in Livestock in Sudan

Background: Rift Valley Fever (RVF) is zoonotic and Transboundary Animal Disease (TAD) that has public health and trade implications for livestock and livestock products. It occurs following heavy rains and is characterized by miscarriages in small ruminants, such as sheep and goats, and illness in humans. The mosquito is the main vector for the disease. It can be transmitted by direct contact with tissues, aerosol, and blood of the infected individual and by ingestion of raw and/or uncooked milk. Purpose: This study aims to estimate the seroprevalence of RVF in Sudan and to determine the geographical distribution of RVF to understand the pattern of its occurrence in Sudan. Methods: This study was conducted in Central Sudan. This study was a retrospective study in which the data were collected mainly from archives and records of the laboratory and were used to estimate the seropositivity. The target population in this study was concentrated on livestock, especially ruminants. Results: In this study, the overall seroprevalence of RVF was estimated to be 16%. The highest seroprevalence was recorded at 66% in cattle in River Nile (95% CI [60.37171, 73.44393]), whereas the lowest seroprevalence was recorded at 0.8% in cattle in Blue Nile (95% CI [0.73293, 0.96704]). Conclusion: This study concluded that herd immunity is a significant factor in understanding the epidemiology of RVF in Sudan. In addition, the retrospective data provided a roadmap for managing and controlling transboundary diseases that have had an impact on human health.

Seroprevalence and associated risk factors of brucellosis, Rift Valley fever and Q fever among settled and mobile agro-pastoralist communities and their livestock in Chad.

Brucellosis, Rift Valley fever (RVF) and Q fever are zoonoses prevalent in many developing countries, causing a high burden on human and animal health. Only a few studies are available on these among agro-pastoralist communities and their livestock in Chad. The objective of our study was to estimate brucellosis, RVF and Q fever seroprevalence among Chadian agro-pastoralist communities and their livestock, and to investigate risk factors for seropositivity. We conducted a multi-stage cross-sectional serological survey in two rural health districts, Yao and Danamadji (966 human and 1041 livestock (cattle, sheep, goat and equine) samples)). The true seroprevalence were calculated applying a Bayesian framework to adjust for imperfect diagnostic test characteristics and accounting for clustering in the study design. Risk factors for each of the zoonotic diseases were estimated using mixed effects logistic regression models. The overall prevalence for brucellosis, Q fever and RVF combined for both regions was estimated at 0.2% [95% credibility Interval: 0-1.1], 49.1% [%CI: 38.9-58.8] and 28.1% [%CI: 23.4-33.3] in humans, and 0.3% [%CI: 0-1.5], 12.8% [%CI: 9.7-16.4] and 10.2% [%CI: 7.6-13.4] in animals. Risk factors correlating significantly with the respective disease seropositivity were sex for human brucellosis, sex and Q fever co-infection for animal brucellosis, age for human Q fever, species and brucellosis co-infection for animal Q fever, age and herd-level animal RVF seroprevalence within the same cluster for human RVF, and cluster-level human RVF seroprevalence within the same cluster for animal RVF. In Danamadji and Yao, Q fever and RVF are notably seroprevalent among agro-pastoralist human and animal communities, while brucellosis appears to have a low prevalence. Correlation between the seroprevalence between humans and animals living in the same communities was detected for RVF, highlighting the interlinkage of human and animal transmissible diseases and of their health, highlighting the importance of a One Health approach.

Geostatistical Modeling and Prediction of Rift Valley Fever Seroprevalence among Livestock in Uganda.

Uganda reported cases of Rift Valley fever virus (RVFV) for the first time in almost 50 years in 2016, following an outbreak of Rift Valley fever (RVF) that caused four human infections, two of which resulted in death. Subsequent outbreak investigation serosurveys found high seroprevalence of IgG antibodies without evidence of acute infection or IgM antibodies, suggesting the possibility of undetected RVFV circulation prior to the outbreak. After the 2016 outbreak investigation, a serosurvey was conducted in 2017 among domesticated livestock herds across Uganda. Sampling data were incorporated into a geostatistical model to estimate RVF seroprevalence among cattle, sheep, and goats. Variables resulting in the best fit to RVF seroprevalence sampling data included annual variability in monthly precipitation and enhanced vegetation index, topographic wetness index, log human population density percent increase, and livestock species. Individual species RVF seroprevalence prediction maps were created for cattle, sheep, and goats, and a composite livestock prediction was created based on the estimated density of each species across the country. Seroprevalence was greater in cattle compared with sheep and goats. Predicted seroprevalence was greatest in the central and northwestern quadrant of the country, surrounding Lake Victoria, and along the Southern Cattle Corridor. We identified areas that experienced conditions conducive to potential increased RVFV circulation in 2021 in central Uganda. An improved understanding of the determinants of RVFV circulation and locations with high probability of elevated RVF seroprevalence can guide prioritization of disease surveillance and risk mitigation efforts.

Seasonal Transmission Dynamics of Rift Valley Fever in Kilimanjaro Region, Tanzania

Background: Rift Valley Fever (RVF) is a zoonotic disease that affects both animals and humans. Under reporting, misdiagnosis caused by the broad spectrum of symptoms presented by the disease, and limited access to rapid and accurate laboratory confirmation have led to an undefined burden of RVF. Reports are available that show the circulation of the virus during inter-epidemic periods, implying an endemic circulation of RVFV. This study aimed to determine RVFV transmission across annual seasons and demographic factors that are independently associated with exposure to RVFV. Methodology: Repeated serosurveys were performed during the long rainy, short rainy, and dry seasons in Lower Moshi area of Moshi district, Kilimanjaro region from January to December 2020. The goal was to determine seroprevalence against RVFV antibodies in humans and factors associated with seropositivity. Detection of RVF antibody was performed by competitive Enzyme-Linked Immunosorbent Assays (cELISA) using serum samples. Stata statistical software version 15 was used for data analysis. Descriptive statistics was carried out, whereby categorical variables were summarised using frequencies and percentages. Numeric variables were summarised using median and interquartile range. Logistic regression was used to assess factors associated with RVF seropositivity. Results: A total of 446 individuals were involved in the analysis. RVF seroprevalence was highest during rainy season (20.4%) and lowest in the dry season (4%). The overall annual seroprevalence of RVF was 12.8%. Season, participant age, and large number of residents in a given household were found to be significantly associated with RVF seropositivity (p<.05). Conclusion: RVFV demonstrates an endemic circulation in Lower Moshi area of Kilimanjaro region, suggesting the site is a potential RVF hotspot. Based on this study’s findings, we recommend close surveillance of RVF in the study area and other areas with similar ecology in Tanzania as a means of preparedness for future unpredicted RVF outbreaks.

Sero-Prevalence of Rift Valley Fever and Brucellosis in Cattle of Northern Benin, West Africa

Sero-Prevalence of Rift Valley Fever and Brucellosis in Cattle of Northern Benin, West Africa

Seroprevalence and associated risk factors of rift valley fever and crimean congo hemorrhagic fever viruses in livestock and their zoonotic potentials: A systematic review

A systematic review was carried out to identify scientific articles documenting on seroprevalence of Rift valley fever and Crimean Congo hemorrhagic fever infections of Livestock and human known to date to cause disease with associated risk in articles published from 2011 to 2021. Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA) 2020 expanded checklist was used to summarize the article selection process. Search strategy was developed to retrieve eligible studies from PubMed (Medline)/OVOID, Animal Health and Production Compendium (CABI) and SciQuest (NZVA). The preliminary search retrieved 2,213 articles on the specified areas: 1,515 articles on Rift Valley Fever Virus, 698 articles on Crimean-Congo Haemorrhagic Fever Virus. Finally a total of 106, (64 on RVFV and 42 on CCHFV) openly available articles were retained for the review process from 30 and 23 different countries respectively. The articles were clustered in to three: articles on livestock sera, articles on human sera and articles from both human and different livestock (Cattle, Sheep, Goat and Camel) serum. The systematic review showed that pooled seroprevalence of RVFV (13.16%) and CCHFV (9.6%). The descriptive statistical analysis revealed statistical difference in the seroprevalence of Rift valley fever in sheep, Goat and camel (χ2 =771.857840, 787.903297, 358.448980; p-value=0.002971*, 0.008652*, 0.000000**) respectively in different countries. This systematic review reflects circulation of RVF and CCKF with complex ecology of vector-borne diseases and the establishment of sustained transmission and the emergence of human and/or animal disease influenced by multiple factors. Therefore, the review indicated that there should be an urgent need for both cost-effective and efficient surveillance systems that focus sampling in the right place at the right time.

Serological evidence of Rift Valley fever virus infection among domestic ruminant herds in Uganda

BackgroundPrior to the first recorded outbreak of Rift Valley fever (RVF) in Uganda, in March 2016, earlier studies done until the 1970’s indicated the presence of the RVF virus (RVFV) in the country, without any recorded outbreaks in either man or animals. While severe outbreaks of RVF occurred in the neighboring countries, none were reported in Uganda despite forecasts that placed some parts of Uganda at similar risk.The Ministry of Agriculture, Animal Industry and Fisheries (MAAIF) undertook studies to determine the RVF sero-prevalence in risk prone areas.Three datasets from cattle sheep and goats were obtained; one from retrospective samples collected in 2010–2011 from the northern region; the second from the western region in 2013 while the third was from a cross-sectional survey done in 2016 in the south-western region. Laboratory analysis involved the use of the Enzyme Linked Immunosorbent Assays (ELISA). Data were subjected to descriptive statistical analyses, including non-parametric chi-square tests for comparisons between districts and species in the regions.ResultsDuring the Yellow Fever outbreak investigation of 2010–2011 in the northern region, a total sero-prevalence of 6.7% was obtained for anti RVFV reacting antibodies (IgG and IgM) among the domestic ruminant population. The 2013 sero-survey in the western region showed a prevalence of 18.6% in cattle and 2.3% in small ruminants. The 2016 sero-survey in the districts of Kabale, Kanungu, Kasese, Kisoro and Rubirizi, in the south-western region, had the respective district RVF sero-prevalence of 16.0, 2.1, 0.8, 15.1and 2.7% among the domestic ruminants combined for this region; bovines exhibited the highest cumulative sero-prevalence of 15.2%, compared to 5.3 and 4.0% respectively for sheep and goats per species for the region.ConclusionsThe absence of apparent outbreaks in Uganda, despite neighboring enzootic areas, having minimal restrictions to the exchange of livestock and their products across borders, suggest an unexpected RVF activity in the study areas that needs to be unraveled. Therefore, more in-depth studies are planned to mitigate the risk of an overt RVF outbreak in humans and animals as has occurred in neighboring countries.

A serological and hematological study on Rift valley fever and associated risk factors in aborted sheep at Kurdistan province in west of Iran

Rift Valley fever (RVF) is a disease caused by RVF virus (RVFV) which can cause infections in a range of wild and domestic ruminants as well as in humans and characterized by an increased incidence of abortion in ruminants. This study aims to survey the seroprevalence and risk factors of this zoonose among aborted sheep in Kurdistan province, the west of Iran. 182 blood samples were collected from aborted sheep during the past one month under age groups <1, ≥1−3, >3−5 year in four seasons in two groups of border and non-border cities of Kurdistan province. The presence of RVFV-specific Antibodies was investigated by using competitive ELISA. Indirect immunofluorescence assay (IIFA) was used to confirm positive samples, after separation of serum, as well as blood samples were analyzed for description of hematological parameters. Of a total sheep sampled 1.65 % (n = 3) were positive for RVFV antibodies in both test. The results of IIFA were correlated with the ELISA results. All of the positive samples showed leucopenia and had significant relation with seroprevalence of RVF (P < 0.05). The seroprevalence of RVF in the border cities were significantly higher than other group (P < 0.05) Age of sheep and season had no significant effect on prevalence of RVF (P > 0.05). Results obtained in this study indicated the presence of low-level RVFV circulation among the sheep of Kurdistan Province in Iran, so it is necessary to carry out further studies in other areas of Iran. Doing an epidemiologically study aimed at isolating RVFV in the ruminants of Kurdistan province is recommended. The risk factor of bordering with Iran's western neighbor (Iraq) requires seriously control of the exchange of animals and the relevant products between the two countries.

Sero-prevalence of brucellosis, Q-fever and Rift Valley fever in humans and livestock in Somali Region, Ethiopia.

Information on zoonotic diseases in humans and livestock are limited in pastoral/agro-pastoral communities in Ethiopia. A multi-stage cross sectional cluster design study was implemented with the aim to establish the seroprevalence of zoonotic diseases including brucellosis, Q-fever and Rift Valley fever (RVF) in humans and livestock in Adadle Woreda of the Somali Region, Ethiopia. Blood samples were collected from humans and livestock and tested by relevant serological tests. For brucellosis, Rose Bengal test (RBT) and indirect ELISA was used for screening and confirmatory diagnosis respectively. Indirect and competitive ELISA were also used for Q-fever and RVF respectively. The individual seropositivity of Q-fever in livestock was 9.6% (95% CI 5.9–15.1) in cattle, 55.7% (95% CI 46.0–65.0) in camels, 48.8% (95% CI 42.5–55.0) in goats, and 28.9% (95% CI 25.0–33.2) in sheep. In humans, seropositivity of Q-fever was 27.0% (95% CI 20.4–34.0), with prevalence in males of 28.9% vs 24.2% in females (OR = 1.3; 95% CI 0.6–2.5). Camel seropositivity of Q-fever was significantly associated with age (OR = 8.1; 95% CI 2.8–23.7). The individual apparent seroprevalence of RVF was 13.2% (95% CI 8.7–18.8) in humans, 17.9% (95% CI 11.0–27.8) in cattle, 42.6% (95% CI 34.8–50.7) in camels, 6.3% (95% CI 3.3–11.6) in goats and 7.4% (95% CI 4.7–11.5) in sheep. Camels had the highest seropositivity of both Q-fever and RVF. Only a weak correlation was observed between human and livestock seropositivity for both Q-fever and RVF. Only cattle and camels were seropositive for brucellosis by iELISA. The individual seroprevalence of brucellosis was 2.8(0.9–6.4) in humans, 1.5% (95% CI 0.2–5.2) in cattle and 0.6% (95% CI 0.0–3.2) in camels. This study showed the importance of zoonoses in Somali Region and is the first published study to describe RVF exposure in humans and livestock in the country. Even though human exposure to RVF virus was reported, public health sector of Somali Region has not given attention to such zoonoses. Collaboration between public and animal health sectors for further investigation on these zoonoses using the One Health concept is indispensable.

Seroprevalence of Rift Valley Fever and West Nile Fever in Cattle in Gambella Region, South West Ethiopia.

IntroductionRift Valley fever (RVF) and West Nile fever (WNF) are re-emerging mosquito-borne zoonotic diseases that cause public health and economic crises. Ethiopia shares borders with South Sudan and Kenya, where these diseases are often documented. The free movement of animals and humans across these borders expects to increase the spread of these diseases. The current study was conducted to assess the occurrence of these diseases in the Gambella region of Ethiopia.MethodologyWe collected a total of 368 cattle serum samples from the Lare district on the border of South Sudan and measured the presence of IgG antibody against RVF and WNF virus infections using enzyme-linked immunosorbent assays (ELISA).ResultsThe prevalence of anti-RVF virus IgG antibody was 7.6% (95% CI: 5.3–10.82%), while that of anti-WNF virus IgG antibody was 5.4% (95% CI: 3.52–8.29%). In this study higher seroprevalence of IgG antibodies to RVF virus infection was observed comparing to the WNF virus in cattle. There was no significant association between the prevalence and the cattle age, sex or sampled locations.ConclusionThe detection of IgG antibody to RVF and WNF virus infections in the Gambella region warrants further study of active case findings and the dynamics of transmission.

A comment on ‘Seroprevalence of Rift Valley fever in South African domestic and wild suids (1999–2016)’

The authors declare no conflict of interest relevant to this article.

Seroprevalence of Rift valley fever in South African domestic and wild suids (1999–2016)

Rift valley fever (RVF) is a vector-borne viral disease of domestic ruminants, camels and man, characterized by widespread abortions and neonatal deaths in animals, and flu-like symptoms, which can progress to hepatitis and encephalitis in humans. The disease is endemic in Africa, Saudi Arabia and Yemen, and outbreaks occur after periods of high rainfall, or in environments supporting the proliferation of RVF virus (RVFV)-infected mosquito vectors. The domestic and wild animal maintenance hosts of RVFV, which may serve as sources of virus during inter-epidemic periods (IEPs) and contribute to occurrence of sporadic outbreaks, remain unknown, although reports indicate that the African buffalo (Syncerus caffer) may play a role. Due to the close proximity of the habitats of domestic pigs and warthogs to those of known domestic and wild ruminant RVFV maintenance hosts respectively, our study investigated their possible role in the epidemiology of RVF in South Africa by evaluating RVFV exposure and seroconversion in suids. A total of 107 warthog and 3,984 domestic pig sera from 2 and all 9 provinces of South Africa, respectively, were screened for presence of RVFV neutralizing antibodies using the virus neutralization test (VNT). Sero-positivity rates of 1.87% (95% CI: 0.01%-6.9%) and 0.68% (95% CI: 0.49%-1.04%) were observed for warthogs and domestic pigs, respectively, but true prevalence rates, taking test sensitivity and specificity into account, were lower for both groups. There was a strong association between the results of the two groups (χ2 =0.75, p=.38), and differences in prevalence between the epidemic and IEPs were non-significant for all suid samples tested (p>.05). This study, which provides the first evidence of probable exposure and infection of South African domestic pigs and warthogs to RVFV, indicates that further investigations are warranted, to fully clarify the role of suids in the epidemiology of RVF.

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

Rift Valley fever (RVF) is a zoonotic mosquito-borne disease caused by RVF virus (RVFV) that causes abortions and high mortalities in livestock and is also associated with acute and fatal disease in humans. In the Democratic Republic of Congo (DRC), information on the epidemiology of RVF is limited, particularly among cattle reared by smallholder farmers. This cross-sectional study was conducted to investigate the seroprevalence of RVF in cattle raised by smallholder farmers in Kwilu Province of DRC, which has not yet reported an RVF epidemic. A total of 677 cattle sera were collected from four territories and tested for anti-RVFV antibodies using immunofluorescent assay and enzyme-linked immunosorbent assay. The overall seroprevalence of anti-RVFV IgG was 6.5% (44/677) (95% CI 4.81-8.7). There was a statistically significant difference in the seroprevalence among the territories (χ2 = 28.79, p < 0.001). Territory seroprevalences were as follows: Idiofa 14.08% (95% CI 9.78-19.76), Bulungu 4.14% (95% CI 1.83-8.68), Gungu 3.21% (95% CI 1.41-6.78), and Masi-Manimba 1.19% (95% CI 0.06-7.37). Seroprevalence differed significantly among age categories (p = 0.0017) and ecosystem (p < 0.001). The seroprevalence of animals aged between 1 and 2years was 20.0% (95% CI 8.4-39.13) and was higher than group aged <1year, between 2 and 3years, and > 3years. Forest area (18.92% (95% CI 12.35-27.7)) had higher seropositivity than savannah area (4.06% (95% CI 2.65-6.12)). Sex difference was not significant (χ2 = 0.14, p = 0.704). These findings indicate that cattle in Kwilu Province had been exposed to RVFV, which represents a significant risk for both livestock and human health.

Zoonotic Rift Valley fever virus prevalence and risk factors in the Lake Zone of Tanzania

Zoonotic Rift Valley fever virus prevalence and risk factors in the Lake Zone of Tanzania

Rift Valley fever seroprevalence and abortion frequency among livestock of Kisoro district, South Western Uganda (2016): a prerequisite for zoonotic infection

BackgroundRift Valley fever (RVF) is classified as viral hemorrhagic fever and is endemic in East and West Africa. RVF is caused by an arthropod borne virus (RVFV); the disease is zoonotic and affects human, animal health as well as international trade. In livestock it causes abortions, while human infection occurs through close contact with infected animals or animal products.MethodsA quantitative observational study using stratified sampling was conducted in the western region of Uganda. Blood samples and abortion events from 1000 livestock (goats, sheep and cattle) was collected and recorded. Serum was analyzed for RVFV IgG reacting antibodies using competitive ELISA test.ResultsThe overall RVFV seroprevalence was of 10.4% (104/1000). Cattle had the highest seroprevalence (7%) followed by Sheep (2.2%) then goats (1.2%). Species specific RVFV seroprevalence was highest in cattle (20.5%) followed by sheep (6.8%) then goats (3.6%). RVFV seroprevalence in northern highlands (21.8%) was significantly higher (p < 0.001) than in the southern lowlands (3.7%). Overall prevalence of abortion was (17.4%), sheep had the highest prevalence of abortion (7.8%) followed by goats (6.3%) and then cattle (3.3%). Species specific abortion prevalence was highest in Sheep (24.1%) followed by goats (18.8%) and then 9.7% in cattle.ConclusionRVFV is endemic in Kisoro district and livestock in the highland areas are more likely to be exposed to RVFV infection compared to those in the southern lowlands. Out breaks in livestock most likely will lead to zoonotic infection in Kisoro district.

Reprint of “Epidemiology of brucellosis, Q Fever and Rift Valley Fever at the human and livestock interface in northern Côte d’Ivoire”

Northern Côte d’Ivoire is the main livestock breeding zone and has the highest livestock cross-border movements in Côte d’Ivoire. The aim of this study was to provide updated epidemiological data on three neglected zoonotic diseases, namely brucellosis, Q Fever and Rift Valley Fever (RVF). We conducted three-stage cross-sectional cluster surveys in livestock and humans between 2012 and 2014 in a random selection of 63 villages and a sample of 633 cattle, 622 small ruminants and 88 people. We administered questionnaires to capture risk factors and performed serological tests including the Rose Bengal Plate Test (RBPT), Brucella spp. indirect and competitive ELISAs, Coxiella burnetii indirect ELISA and RVF competitive ELISA. The human seroprevalence for Brucella spp. was 5.3%. RBPT-positive small ruminants tested negative by the indirect ELISA. The seroprevalence of Brucella spp. in cattle adjusted for clustering was 4.6%. Cattle aged 5–8 years had higher odds of seropositivity (OR=3.5) than those aged ≤4years. The seropositivity in cattle was associated with having joint hygromas (OR=9), sharing the pastures with small ruminants (OR=5.8) and contact with pastoralist herds (OR=11.3). The seroprevalence of Q Fever was 13.9% in cattle, 9.4% in sheep and 12.4% in goats. The seroprevalence of RVF was 3.9% in cattle, 2.4% in sheep and 0% in goats. Seropositive ewes had greater odds (OR=4.7) of abortion than seronegative ones. In cattle, a shorter distance between the night pens and nearest permanent water bodies was a protective factor (OR=0.1). The study showed that the exposure to the three zoonoses is rather low in northern Côte d’Ivoire. Within a One Health approach, cost-benefit and cost-effectiveness of control measures should be assessed for an integrated control.

Seroprevalence of Rift Valley fever in cattle along the Akagera-Nyabarongo rivers, Rwanda.

Rift Valley fever (RVF) virus is caused by a zoonotic arbovirus that is endemic to eastern and southern Africa. It has also been reported in West and North Africa, Madagascar and the Arabian Peninsula. The virus is transmitted by mosquitoes, but people can also become infected while handling blood or other body fluids of animals and humans with RVF. In 2007, there was a large outbreak of RVF in Kenya, Tanzania, Sudan and Somalia. Outbreaks were also reported in South Africa in 2008–2011. The epidemiology of RVF and factors for disease occurrence in Rwanda are neither clear nor documented. Therefore, we conducted a cross-sectional study from December 2012 to March 2013 to generate baseline information on RVF in cattle. Purposive sampling of cattle (n = 595) was done in six districts, and serum samples were screened with competitive enzyme-linked immunosorbent assay (ELISA). We performed a statistical analysis on the generated data, and risk factors associated with RVF seroprevalence were determined by a simple logistic regression. Overall, RVF seroprevalence was 16.8% (95% confidence interval [CI] [13.8% – 20.0%]). The highest seroprevalence was recorded in Kirehe district (36.9%) followed by Ngoma (22.3%), and the least was recorded in Nyagatare (7.9%). RVF was more likely to occur in adult cattle (19.9% [odds ratio {OR} = 1.88, 95% CI {0.98–3.61}]) compared to young cattle (10.5% [OR = 0.47, 95% CI {0.26–0.83}]). Pure exotic or cross-breeds were significantly exposed to RVF virus (seroprevalence 22.9% [OR = 4.26, 95% CI {1.82–9.99}]) in comparison to 14.1% (OR = 0.55, 95% CI [0.35–0.86]) in local breeds. Sex differences were not statistically significant. These findings indicated that cattle have been exposed to RVF virus in six districts in Rwanda with a significant risk in adult, exotic or cross-breeds in Kirehe district.

Seroprevalence of Rift Valley fever in cattle along the Akagera–Nyabarongo rivers, Rwanda

Seroprevalence of Rift Valley fever in cattle along the Akagera–Nyabarongo rivers, Rwanda

Seroepidemiological Survey of Rift Valley Fever Virus in Ruminants in Garissa, Kenya.

Rift Valley fever (RVF) is a vector-borne zoonotic disease caused by phlebovirus in the family Bunyaviridae. In Kenya, major outbreaks occurred in 1997-1998 and 2006-2007 leading to human deaths, huge economic losses because of livestock morbidity, mortality, and restrictions on livestock trade. This study was conducted to determine RVF seroprevalence in cattle, sheep, and goats during an interepidemic period in Garissa County in Kenya. In July 2013, we performed a cross-sectional survey and sampled 370 ruminants from eight RVF-prone areas of Garissa County. Rift Valley fever virus (RVFV) antibodies were detected using a multispecies competitive enzyme-linked immunosorbent assay. Mixed effect logistic regression models were used to determine the association between RVF seropositivity and species, sex, age, and location of the animals. A total of 271 goats, 87 sheep, and 12 cattle were sampled and the overall immunoglobulin G seroprevalence was 27.6% (95% CI [23-32.1]). Sheep, cattle, and goats had seroprevalences of 32.2% (95% CI [20.6-31]), 33.3% (95% CI [6.7-60]), and 25.8% (95% CI [22.4-42]), respectively. Seropositivity in males was 31.8% (95% CI [22.2-31.8]), whereas that of females was 27% (95% CI [18.1-45.6]). The high seroprevalence suggests RVFV circulation in domestic ruminants in Garissa and may be indicative of a subclinal infection. These findings provide evidence of RVF disease status that will assist decision-makers to flag areas of high risk of RVF outbreaks and prioritize the implementation of timely and cost-effective vaccination programs.

Epidemiology of brucellosis, Q Fever and Rift Valley Fever at the human and livestock interface in northern Côte d’Ivoire

Northern Côte d’Ivoire is the main livestock breeding zone and has the highest livestock cross-border movements in Côte d’Ivoire. The aim of this study was to provide updated epidemiological data on three neglected zoonotic diseases, namely brucellosis, Q Fever and Rift Valley Fever (RVF). We conducted three-stage cross-sectional cluster surveys in livestock and humans between 2012 and 2014 in a random selection of 63 villages and a sample of 633 cattle, 622 small ruminants and 88 people. We administered questionnaires to capture risk factors and performed serological tests including the Rose Bengal Plate Test (RBPT), Brucella spp. indirect and competitive ELISAs, Coxiella burnetii indirect ELISA and RVF competitive ELISA. The human seroprevalence for Brucella spp. was 5.3%. RBPT-positive small ruminants tested negative by the indirect ELISA. The seroprevalence of Brucella spp. in cattle adjusted for clustering was 4.6%. Cattle aged 5–8 years had higher odds of seropositivity (OR=3.5) than those aged ≤4years. The seropositivity in cattle was associated with having joint hygromas (OR=9), sharing the pastures with small ruminants (OR=5.8) and contact with pastoralist herds (OR=11.3). The seroprevalence of Q Fever was 13.9% in cattle, 9.4% in sheep and 12.4% in goats. The seroprevalence of RVF was 3.9% in cattle, 2.4% in sheep and 0% in goats. Seropositive ewes had greater odds (OR=4.7) of abortion than seronegative ones. In cattle, a shorter distance between the night pens and nearest permanent water bodies was a protective factor (OR=0.1). The study showed that the exposure to the three zoonoses is rather low in northern Côte d’Ivoire. Within a One Health approach, cost-benefit and cost-effectiveness of control measures should be assessed for an integrated control.