Enemies and turncoats: bovine tuberculosis exposes pathogenic potential of Rift Valley fever virus in a common host, African buffalo (Syncerus caffer).

We investigated the relationship between prevalence and severity of clinical signs of Demodex cafferi infection in free-ranging African buffalo (Syncerus caffer) and other factors such as age, sex, pregnancy status, and concomitant infections with bovine tuberculosis (BTB), Rift Valley fever (RVF), and brucellosis (BA). Approximately half of 203 buffalo examined in this study had clinical signs of demodicosis (cutaneous nodules); younger age classes had the highest prevalence and severity of lesions (chi(2)=21.4, df=6, P=0.0015). Nodules were generally limited to the head and neck region, but in severe cases were present over the entire animal. We found no significant association between clinical severity of the Demodex infection and gender, pregnancy status, or infection with BTB, RVF, or BA.

Rift Valley fever and lumpy skin disease are transboundary viral diseases endemic in Africa and some parts of the Middle East, but with increasing potential for global emergence. Wild ruminants, such as the African buffalo (Syncerus caffer), are thought to play a role in the epidemiology of these diseases. This study sought to expand the understanding of the role of buffalo in the maintenance of Rift Valley fever virus (RVFV) and lumpy skin disease virus (LSDV) by determining seroprevalence to these viruses during an inter-epidemic period. Buffaloes from the Kruger National Park (n = 138) and Hluhluwe-iMfolozi Park (n = 110) in South Africa were sampled and tested for immunoglobulin G (IgG) and neutralising antibodies against LSDV and RVFV using an indirect enzyme-linked immunosorbent assay (I-ELISA) and the serum neutralisation test (SNT). The I-ELISA for LSDV and RVFV detected IgG antibodies in 70 of 248 (28.2%) and 15 of 248 (6.1%) buffaloes, respectively. Using the SNT, LSDV and RVFV neutralising antibodies were found in 5 of 66 (7.6%) and 12 of 57 (21.1%), respectively, of samples tested. The RVFV I-ELISA and SNT results correlated well with previously reported results. Of the 12 SNT RVFV-positive sera, three (25.0%) had very high SNT titres of 1:640. Neutralising antibody titres of more than 1:80 were found in 80.0% of the positive sera tested. The LSDV SNT results did not correlate with results obtained by the I-ELISA and neutralising antibody titres detected were low, with the highest (1:20) recorded in only two buffaloes, whilst 11 buffaloes (4.4%) had evidence of co-infection with both viruses. Results obtained in this study complement other reports suggesting a role for buffaloes in the epidemiology of these diseases during inter-epidemic periods.

Rift Valley fever virus (RVFV) is an emerging biodefense pathogen that poses significant threats to human and livestock health. To date, the interepidemic reservoirs of RVFV are not well defined. In a longitudinal survey of infectious diseases among African buffalo during 2000-2006, 550 buffalo were tested for antibodies against RVFV in 820 capture events in 302 georeferenced locations in Kruger National Park, South Africa. Overall, 115 buffalo (21%) were seropositive. Seroprevalence of RVFV was highest (32%) in the first study year, and decreased progressively in subsequent years, but had no detectable impact on survival. Nine (7%) of 126 resampled, initially seronegative animals seroconverted during periods outside any reported regional RVFV outbreaks. Seroconversions for RVFV were detected in significant temporal clusters during 2001-2003 and in 2004. These findings highlight the potential importance of wildlife as reservoirs for RVFV and interepidemic RVFV transmission in perpetuating regional RVFV transmission risk.

Rift Valley fever (RVF) was first characterized by Daubney and his co-workers, Hudson and Garnham in 1934, while working at the Veterinary Research Laboratory at Kabete in Kenya. An earlier report by Stordy, working in the same department in 1913, had described a similar disease syndrome, which may well have been RVF; it presented as an acute and highly fatal disease in the Rift Valley in exotic wool sheep, which had been imported into East Africa. An association of the disease with heavy and prolonged rainy seasons was noted. Epizootics occurred periodically in Kenya until the disease was recognized in South Africa in 1951, when humans became ill after handling dead and infected animals. Sheep and to a lesser extent cattle were the principle disease hosts in both east and southern Africa. Further epizootics were subsequently confirmed in Zimbabwe, Zambia, the Sudan, and other east African countries. In 1977 there was a major epidemic in Egypt, with 20–40,000 clinical illnesses and 600 deaths. Cattle and sheep suffered from abortions and neonatal mortality; goats, camels, and water buffalo were also affected. Subsequently, RVF was identified in West Africa in Senegal and Mauritania, where human mortality was again high. In 2000, an outbreak occurred in Saudi Arabia, the first occurrence of RVF virus (RVFV) outside Africa. The ecology there is identical with that in enzootic zones in Africa and the RVF, which circulated were the same biotopes as were seen in Africa. Today, it is generally acknowledged that RVFV is enzootic throughout the African continent and Saudi Arabia, and in many African countries, although disease has not been recognized in man nor in animals in a substantial proportion of enzootic countries. Historically, during the major epizootics, the human RVF infections have been predominantly sub-clinical; many present as a mild influenza-like syndrome, commonly attributed to malaria. More serious clinical manifestations are acute febrile syndromes accompanied by findings like severe jaundice, retinitis and other ocular lesions, and encephalitis. These have been variously described to develop in from 5% to 20% of RVFV cases in man. Highly fatal hemorrhagic syndrome (HFS) is the most serious clinical manifestation of RVF infections, and has historically been found in only 1–2% of cases. The first Egyptian (1977) and the more recent RVF epizootics in West Africa and in the East and Horn of Africa in 1997 and 2006, have been characterized by the occurrence of many (several hundred) hemorrhagic fever cases with a significantly high mortality. While occasional cases had been recognized during the many RVF epizootics in the East and South of Africa, these had constituted only 1–2% of the total number of human RVF infections identified. The more recent epizootics in these areas have suggested that HFS was the predominant presenting sign in the affected population groups, and constituted approximately 10% of the human RVF cases. The ecology of RVFV may be relevant to this observation. The RVFV activity occurs in forest and forest edge situations and the moist plains and bushed and wooded grasslands, which are found over much of Africa. Rainfall in these zones is relatively high and RVF enzootic/epizootic activity is most frequently found in these zones. The RVFV transmission in such areas has involved principally the animal disease hosts. However, retrospective studies show that often 20–30% of those humans living and working with the animals during the epizootic period, have seroconverted to RVFV, usually with no manifestation of clinical signs. Human RVF cases with HFS were extremely rarely seen. Hemorrhagic cases of RVF have occurred among human populations of the alluvial flood plain zones, which are found principally in semi-arid regions. It has been tentatively suggested that these cases constituted 10% of all the RVFV cases in the recent 2000 epizootic in the Baringo and NE districts of Kenya. In Egypt in 1977, there were also many such cases. It may be relevant to note that malaria and probably schistosomiasis, were endemic in human populations in these regions. In the semiarid zones of Senegal and Mauretania, and of Kenya and the lowlands of Somalia, where there are flood plains, malaria and probably schistosomiasis commonly occur, with the possibility also today of widespread human immunodeficiency virus (HIV) infections. It is suggested that the outcome of RVFV infection in such population groups, affected by chronic immunosuppressive diseases, may render them much more susceptible to RVF infections and result in a greater proportion of HFS cases.

Introduction: Rift Valley fever (RVF) is an arthropod-borne disease that affects both animals and humans. RVF phlebovirus (RVFPV) is widespread in Africa and Arabian Peninsula. In Mozambique, outbreaks were reported in South; seroprevalence studies performed in livestock and water buffaloes were limited to central and south regions. We evaluated the seroprevalence of RVFPV among domestic ruminants and African buffaloes from 7 of 10 provinces of Mozambique, to understand the distribution of RVFPV and provide data for further RVF control programs. Materials and methods: A total of 1581 blood samples were collected in cattle, 1117 in goats, 85 in sheep and 69 in African buffaloes, between 2013 and 2014, and the obtained sera were analyzed by ELISA. Results and discussion: The overall seroprevalence of RVFPV domestic ruminants and African buffaloes was 25.6%. The highest was observed in cattle (37.3%) and African buffaloes (30.4%), which were higher than in previous studies within Mozambique. In south and central regions, the overall seroprevalences were higher (14.9%–62.4%) than in the north. Conclusion: This study showed the presence of anti-RVFPV antibodies in animals from all sampled provinces, suggesting that RVFPV is actively circulating among domestic ruminants and African buffaloes in Mozambique, therefore surveillance should be intensified.

Rift Valley fever (RVF) virus, a member of family Bunyaviridae, genus Phlebovirus, is a mosquito‐borne zoonotic pathogen endemic to Sub‐Saharan Africa and the Arabian Peninsula that causes severe epizootics in ruminants. RVF outbreaks in ruminants are associated with mass abortions and high mortality in younger animals. Human infections at all ages are associated with acute febrile illness that may progress to more severe disease including encephalitis and severe hepatitis leading to fatal hemorrhagic fever. RVF virus (RVFV) is classified as an overlap select agent by the Center for Disease Control and Prevention and the US Department of Agriculture. In the US, work with virulent RVFV strains must be conducted in BSL‐3+ and requires RVFV specific select agent clearance.In conjunction with ruminant challenge model development for evaluation of new RVFV vaccines and therapies, we have been examining the pathology of RVFV in multiple organs. Our initial histopathology findings warranted examination of infected tissues by transmission electron microscopy (EM). Consequently, during early time‐point post‐infection calf necropsies, we collected 2–5 mm cube sized samples of calf kidney, liver and spleen in room temperature (RT) 2.5% glutaraldehyde in Sorenson's buffer (glut), a standard EM fixative that preserves morphology for EM. Glutaraldehyde shares fixation characteristics with 10% neutral buffered formalin that is already approved for use in our BSL‐3Ag facility. Post ~2 hours at RT, samples were stored at 4° C, as per advice from our EM experts, for a minimum of 7 days. Because glut was a new fixative for our facility, we conducted proof of inactivation tests on our samples. RVFV PCR‐positive, unfixed tissue from each organ of interest from one of the calves and PBS were used as positive and negative controls respectively. Samples were rinsed in PBS, homogenized and blind passaged 3 times using standard virus propagation protocols. The cell monolayers were checked post passage for cytopathic effect (CPE) and standard plaque assays were conducted after the third passage. Additionally, in a separate experiment, using full strength and serially diluted glut in a no virus simulated viral propagation protocol, we tested for a direct toxicity effect of glut on our Vero cells during the initial 1 hr incubation time‐period.Plaque formation was observed on cells incubated with glut samples containing RVFV‐positive tissues and positive control tissues but not on cells incubated with PBS or glut. This indicates that the glut treated tissue samples still contained viable RVFV. Currently, we have experiments planned to consider the role of temperature in glut viral inactivation.Support or Funding InformationThis work was funded by grants of the Department of Homeland Security Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), Grant No. 2010‐ST061‐AG0001, USDA Agricultural Services project 3020‐32000‐005‐00D and the Kansas Bioscience Authority.

Goat seropositivity as an indicator of Rift Valley fever (RVF) infection in human populations: A case-control study of the 2018 Rift Valley fever outbreak in Wajir County, Kenya

Aim:This study was designed to investigate the current epidemiological situation of bovine viral diarrhea virus (BVDV) and rift valley fever virus (RVFV) infection of camels originating from Sudan “smuggler” and Egypt as part of our future plan for a national surveillance program in Egyptian provinces, which will aid in establishment of control strategy for animal diseases.Materials and Methods:This investigation was accomplished using serological diagnostic and molecular biology techniques. A total number of 200 blood samples were collected from camel (120 originated from Sudan “smuggler” and 80 from local breed) and were subjected for testing both BVDV and RVFV occurrence with different age and sex.Results:Sixty-six of the 200 camels (33%) were positive for BVDV antibodies, and 44 (22%) for BVDV antigen (Ag), and 27 of the 200 camels (13.5%) were positive for RVFV immunoglobulin G (IgG) antibodies. On the other hand, the seroprevalence of BVDV for antibodies (47.5%), Ag (31.6%), and RVFV IgG antibodies (16.6%) was higher in camel originated from Sudan “smuggler” than of local breed which was 11.2% for BVDV antibodies and 7.5% for BVDV Ag, while it was 8.7% for RVFV IgG antibodies. The incidence of BVDV antibodies, Ag, and RVFV IgG antibodies was the highest in male, up to 9 years of age. The frequency of positive cases was significantly different according to the origin of samples and sex and age of camel for BVDV and RVFV. In addition, seven serologically positive samples for BVDV and five serologically positive samples for RVFV were submitted as a buffy coat for molecular detection by one-step – reverse transcription polymerase chain reaction (RT-PCR). The results demonstrated that three samples were positive for BVDV of camel originated from Sudan (smuggler), while no RVFV Ag was detected in all five samples. Sequencing and phylogenetic analysis of the amplicons obtained from positive RT-PCR samples (three samples) indicated 100% nucleotide homology with Sudan strain 2015 except only one (missense point mutation) by substitution of A to T at position 345 that changed the coded amino acids from T (Threonine) to S (Serine) at residue 115.Conclusion:Camels act as risk animals for the introduction of many infectious diseases from Sudan to Egypt, especially transboundary animal diseases, so strict quarantine measures should be taken during importation of live animals from Sudan to prevent the spread of such diseases.

Rift Valley fever (RVF) is a zoonotic mosquito-borne virus disease of livestock and wild ruminants that has been identified as a risk for international spread. Typically, the disease occurs in geographically limited outbreaks associated with high rainfall events and can cause massive losses of livestock. It is unclear how RVF virus persists during inter-epidemic periods but cryptic cycling of the virus in wildlife populations may play a role. We investigated the role that free-living African buffalo (Syncerus caffer caffer) might play in inter-epidemic circulation of the virus and looked for geographic, age and sex patterns of Rift Valley fever virus (RVFV) infection in African buffalo. Buffalo serum samples were collected (n=1615) in Kruger National Park (KNP), South Africa, during a period of 1996-2007 and tested for antibodies to RVF. We found that older animals were more likely to be seropositive for anti-RVFV antibody than younger animals, but sex was not correlated with the likelihood of being anti-RVFV antibody positive. We also found geographic variation within KNP; herds in the south were more likely to have acquired anti-RVFV antibody than herds farther north - which could be driven by host or vector ecology. In all years of the study between 1996 and 2007, we found young buffalo (under 2years of age) that were seropositive for anti-RVFV antibody, with prevalence ranging between 0 and 27% each year, indicating probable circulation. In addition, we also conducted a 4-year longitudinal study on 227 initially RVFV seronegative buffalo to look for evidence of seroconversion outside known RVF outbreaks within our study period (2008-2012). In the longitudinal study, we found five individuals that seroconverted from anti-RVFV antibody negative to anti-RVFV antibody positive, outside of any detected outbreak. Overall, our results provide evidence of long-term undetected circulation of RVFV in the buffalo population.

The African buffalo (Syncerus caffer) is a large wild bovid which until recently ranged across all but the driest parts of sub-Saharan Africa, and their local range being limited to about 20 km from surface water. They are of high ecological value due to their important role as bulk feeders in the grazing hierarchy. They also have high economic value, because they are one of the sought after 'Big Five' in the eco-tourism industry. In Africa, buffaloes have been recognised for some time as an important role player in the maintenance and transmission of a variety of economically important livestock diseases at the wildlife and/or livestock interface. These include African strains of foot-and-mouth disease (FMD), Corridor disease (theileriosis), bovine tuberculosis and bovine brucellosis. For a number of other diseases of veterinary importance, African buffaloes may also serve as amplifier or incidental host, whereby infection with the causative pathogens may cause severe clinical signs such as death or abortion as in the case of anthrax and Rift Valley fever, or remain mild or subclinical for example heartwater. The long term health implications of most of those infections on the buffalo at a population level is usually limited, and they do not pose a threat on the population's survival. Because of their ability to harbour and transmit important diseases to livestock, their sustainable future in ecotourism, trade and transfrontier conservation projects become complex and costly and reliable diagnostic tools are required to monitor these infections in buffalo populations.

Patients with RVF present with symptoms varying from mild flu-like symptoms to severe cases with about 1% developing hemorrhagic disease.Rift valley fever infection (RVFV) can lead to significant morbidity and mortality in humans and up to 2% of cases may be fatal [6].A systematic review done on the clinical manifestations in RVFV in humans revealed that renal complications mainly presented as acute renal failure [2, 4].Although the pathophysiology of RVF-associated AKI and ALF is not fully understood, it is believed to be related to infection of the Abstract Introduction: Rift Valley Fever (RVF) is an endemic zoonotic viral disease which usually affects livestock in parts of Africa and the Middle East.In patients infected with RVF, there is a risk of acute kidney injury (AKI) and acute liver failure (ALF).In this report, we present a case series of four patients diagnosed with RVF infection, highlighting the complications of AKI and ALF, with varying outcomes, including the utilization and impact of dialysis. Methods:We conducted a retrospective analysis of medical records for four patients admitted and managed at Mbarara Regional Referral Hospital (MRRH) in Southwestern Uganda with confirmed Rift Valley Fever infection.Clinical, laboratory, and outcome data were collected and summarized. Results:All four patients presented with characteristic symptoms suggestive of RVF, and laboratory investigations confirmed the diagnosis.Each patient had complications of AKI and acute liver failure.All patients required dialysis for renal support; however, logistical issues prevented access to hemodialysis for all but two of the patients.Among the patients who received hemodialysis, both demonstrated recovery from AKI.Unfortunately, the two patients who were unable to access dialysis succumbed to the complications. Conclusion:RVF infection can lead to severe complications, including AKI and acute liver failure.The timely initiation of dialysis appears crucial for improved outcomes in these cases.However, logistical barriers may hinder access to dialysis, emphasizing the need for improved healthcare infrastructure and accessibility in regions endemic to RVF.

ABSTRACTIn social species, the transmission and maintenance of infectious diseases depends on the contact patterns between individuals within groups and on the interactions between groups. In southern Africa, the Cape buffalo (Syncerus caffer caffer) is a vector for many pathogens that can infect sympatric livestock. Although intra‐group contact patterns of Cape buffalo have been relatively well described, how groups interact with each other and risks for pathogen transmission remain poorly understood. We identified and compared spatial behavior and contact patterns between neighboring groups of Cape buffalo under contrasting environments: within the seasonally flooded environment of the Okavango Delta in Botswana and the semi‐arid environment of northern Kruger National Park in South Africa. We used telemetry data collected between 2007 and 2015 from 10 distinct groups. We estimated seasonal overlap and proximity between home ranges of pairwise neighboring groups, and we quantified seasonal contact patterns between these groups. We defined contact patterns within variable spatiotemporal windows compatible with the transmission of diseases carried by the Cape buffalo: bovine tuberculosis, brucellosis, and Rift Valley fever (mosquito‐borne transmission). We examined the effects of habitat and distance to water on contact location. In both study populations, neighboring buffalo groups were highly spatially segregated in the dry and rainy seasons. Inter‐group contact patterns were characterized by very few direct and short‐term indirect (within 0–2 days) contacts, lasting on average 1 hour and 2 hours, respectively. Contact patterns were generally consistent across populations and seasons, suggesting species‐specific behavior. In the drier study site, the probability of indirect and vector‐borne contacts generally decreased during the dry season with increasing distance to water. In the seasonally flooded area, only the probability of vector‐borne contact decreased with increasing distance to water. Our results highlight the importance of dry season water availability in influencing the dynamics of indirectly transmitted Cape buffalo pathogens but only in areas with low water availability. The results from this study have important implications for future modeling of pathogen dynamics in a single host, and the ecology and management of Cape buffalo at the landscape level. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.

In association with a study investigating the apparent decline of African buffalos (Syncerus caffer) in Ruaha National Park, Tanzania, 40 buffalos were screened for selected diseases. Bovine tuberculosis was detected in 23%, and exposure to Brucella abortus and Rift Valley fever virus in 18% and 8%, respectively, of buffalos tested.

Rift Valley fever (RVF) is a neglected vector-borne disease which is endemic in many countries across Africa and has seen recent geographical expansions into the Arabian Peninsula. RVF can cause severe infections in both animals and humans. RVF infections in livestock can lead to mass fatalities. In humans, the symptoms are nonspecific and can often lead to misdiagnosis. However, a small proportion progresses to haemorrhagic infection with a significantly higher mortality rate. The culmination of this can cause severe socioeconomic impacts. This review aims to identify the main socioeconomic impacts caused by RVF outbreaks as well as existing knowledge gaps. Ninety-three academic and grey papers were selected, covering 19 countries and 10 methodological approaches. A variety of socioeconomic impacts were found across all levels of society: Livestock trade disruptions consequently impacted local food security, local and national economies. Most livestock farmers in endemic countries are subsistence farmers and so rely on their livestock for sustenance and income. RVF outbreaks resulted in a variety of socioeconomic impacts, e.g., the inability to pay for school fees. Main barriers to vaccine uptake in communities were lack of access, funds, interest along with other social aspects. The occupational risks for women (and pregnant women) are largely unknown. To our knowledge, this is the first review on RVF to highlight the clear knowledge gap surrounding the potential gender differences on risks of RVF exposure, as well as differences on occupational health risk in pastoral communities. Further work is required to fill the gaps identified in this review and inform control policies.

To the Editor: Different arboviral diseases have expanded their geographic range in recent times. Of them, Rift Valley fever, West Nile fever, and African horse sickness are of particular concern. They are endemic in sub-Saharan Africa but occasionally spread beyond this area. Trade and transport of animals and animal products, along with wildlife movements, are considered the driving factors in the spread of these pathogens. In wide regions of Africa, 1-humped camels (Camelus dromedarius) are valuable livestock appreciated as a meat source and as a means for transportation of goods. Camels are susceptible to infection by Rift Valley fever virus (RVFV), West Nile virus (WNV), and African horse sickness virus (AHSV), although their epidemiologic role in these diseases is uncertain (1–3). Movements of camels across the Sahara Desert could carry these pathogens to northern Africa. To test this hypothesis, we conducted a serologic survey in 1-humped camels intercepted at different points by the Moroccan Veterinary Services in 2009. The camels were coming from the southeastern part of the Sahara Desert going to the northwest. Serum samples were obtained in Smara-Laayoune, Dakhla, and Tata (Table). Most samples (71 of 100 total samples) were from male camels. Samples were also grouped by age of the camels (Table). RVFV antibodies were detected by using a competitive ELISA (4), and samples yielding positive ELISA results were confirmed by virus-neutralization test. WNV-specific antibodies were detected by ELISA (5), and positive results were confirmed by virus-neutralization test. AHSV-specific antibodies were detected by using the ELISA prescribed by the World Organisation for Animal Health. Table Results of testing of camels for virus antibodies, by location, age group, and sex of camels examined, North Africa, 2009* Fifteen of 100 samples were positive for RVFV-specific antibodies by competitive ELISA, all of which were confirmed by virus-neutralization test, with neutralization titers ranging from 40 to 1,280 (geometric mean titer = 229). With regard to WNV antibodies, the ELISA detected 44 positive samples and 1 doubtful sample, of which 29 were confirmed as positive by virus-neutralization test (virus-neutralization test titers ranging from 10 to 640; geometric mean titer = 20). As for AHSV antibodies, none of the samples was positive by ELISA. Prevalence data were analyzed by generalized linear model with locality (Dakhla or Smara), sex, and age as fixed factors. No differences by origin or sex were found in prevalence for WNV (p>0.14) but antibodies were more prevalent in camels >3 years of age (χ2 = 14.04, 3 df, p = 0.003). No differences in prevalence of RVFV antibodies were found by sex (p = 0.29), but prevalence was higher in Smara (χ2 = 3.74, p = 0.05) and among camels >6 years of age (χ2 = 8.37, df = 3, p = 0.04) (Table). We also examined the co-occurrence of antibodies to RVFV and WNV. Of 15 RVFV-positive samples, 12 were also positive for WNV antibodies, and 12 of 29 WNV-positive samples were also positive for RVFV (χ2 = 8.37, df = 1, p < 0.05). Antibodies to 2 zoonotic arboviruses, i.e., RVFV and WNV, were present in camels moving to the northwestern part of the Sahara Desert, and antibodies to AHSV were absent in the populations examined. Despite the higher percentage of seropositivity for WNV than for RVFV, the epidemiologic consequence of RVFV-specific antibodies in this population could be higher than that for WNV antibodies. Camels can act as reservoir hosts for RVFV (6) but are unlikely to do so for WNV, which cycles between mosquitoes and wild birds with mammals usually being dead-end hosts. High prevalence of antibodies to RVFV in camels has been described in different sub-Saharan and Sahelian countries (7–9). Camels have been involved in the spread of disease in some instances (10). Immunity to RVFV indicates previous infection. Our results showed that seroprevalence of RVFV was higher among older than younger camels, indicating that contact could have occurred some years ago. Nevertheless, these populations should be monitored for RVFV and other arboviroses because these are known to reemerge under certain circumstances in locations where they have occurred in the past. The results of this study support that camels moving across the Sahara have contact with RVFV and WNV, and frequently the same animals have been infected by both agents. In a particularly dry environment such as the desert, particular attention should be paid to singular wet areas such as oases. The presence of water in these areas results in an abundance of competent mosquitoes and hosts, which in turn makes these viruses likely to cycle and infect domestic animals such as camels coming to drink and rest.