Search

Background Crimean-Congo hemorrhagic fever virus (CCHFV) belongs to the genus Orthonairovirus (Nairovididae) and is a (re)emerging tick-borne pathogen. It is endemic in most parts of Africa, Asia and southern Europe, and can cause severe hemorrhagic symptoms in humans, with high fatality rates (5–30%). Methods Hyalomma ticks were collected from four different livestock herds (cattle and camels) in Mauritania in 2018. The tick species were determined morphologically and confirmed molecularly by using the cytochrome oxidase 1 gene marker. For the detection of CCHFV, ticks were tested individually by one-step multiplex real-time reverse-transcriptase quantitative polymerase chain reaction. The small segment of all positive samples was sequenced to determine the CCHFV genotype. Results In total, 39 of the 1523 ticks (2.56%) collected from 63 cattles and 28 camels tested positive for CCHFV. Three Hyalomma species were identified. Hyalomma rufipes had the largest proportion of positivity (5.67%; 16/282), followed by Hyalomma dromedarii (1.89%; 23/1214). No Hyalomma impeltatum tested positive (0%; 0/21). Positive ticks were found in only six out of 91 host animals. Viral sequence analysis revealed the presence of two different CCHFV lineages (Africa I and Africa III). Conclusions In this study, 2.56% of Hyalomma ticks collected from camels and cattle in Mauritania tested positive for CCHFV. However, the true prevalence of CCHFV in unfed ticks may be lower, as a considerable number of ticks may have been passively infected during blood-feeding by co-feeding ticks or due to viremia of the host. The results indicate the need to track the actual area of circulation of this virus. Graphical Abstract

Rift Valley fever virus (RVFV), an arbovirus belonging to the Phlebovirus genus of the Phenuiviridae family, causes the zoonotic and mosquito-borne RVF. The virus, which primarily affects livestock (ruminants and camels) and humans, is at the origin of recent major outbreaks across the African continent (Mauritania, Libya, Sudan), and in the South-Western Indian Ocean (SWIO) islands (Mayotte). In order to be better prepared for upcoming outbreaks, to predict its introduction in RVFV unscathed countries, and to run efficient surveillance programmes, the priority is harmonising and improving the diagnostic capacity of endemic countries and/or countries considered to be at risk of RVF. A serological inter-laboratory proficiency test (PT) was implemented to assess the capacity of veterinary laboratories to detect antibodies against RVFV. A total of 18 laboratories in 13 countries in the Middle East, North Africa, South Africa, and the Indian Ocean participated in the initiative. Two commercial kits and two in-house serological assays for the detection of RVFV specific IgG antibodies were tested. Sixteen of the 18 participating laboratories (88.9%) used commercial kits, the analytical performance of test sensitivity and specificity based on the seroneutralisation test considered as the reference was 100%. The results obtained by the laboratories which used the in-house assay were correct in only one of the two criteria (either sensitivity or specificity). In conclusion, most of the laboratories performed well in detecting RVFV specific IgG antibodies and can therefore be considered to be prepared. Three laboratories in three countries need to improve their detection capacities. Our study demonstrates the importance of conducting regular proficiency tests to evaluate the level of preparedness of countries and of building a network of competent laboratories in terms of laboratory diagnosis to better face future emerging diseases in emergency conditions.

Crimean-Congo hemorrhagic fever virus (CCHFV) is one of the most widespread zoonotic arthropod-borne viruses in many parts of Africa, Europe and Asia. It belongs to the family of Nairoviridae in the genus of Orthonairovirus. The main reservoir and vector are ticks of the genus Hyalomma. Livestock animals (such as cattle, small ruminants and camels) develop a viremias lasting up to two weeks with absence of clinical symptoms, followed by seroconversion. This study was carried out to assess risk factors that affect seroprevalence rates in different species. In total, 928 livestock animal samples (cattle = 201; sheep = 247; goats = 233; camels = 247) from 11 out of 13 regions in Mauritania were assayed for CCHFV-specific immunoglobulin G (IgG) antibodies using enzyme-linked immunosorbent assays (ELISA) (including a novel indirect camel-IgG-specific CCHFV ELISA). Inconclusive results were resolved by an immunofluorescence assay (IFA). A generalized linear mixed-effects model (GLMM) was used to draw conclusions about the impact of certain factors (age, species, sex and region) which might have influenced the CCHFV antibody status of surveyed animals. In goats and sheep, about 15% of the animals were seropositive, whereas in cattle (69%) and camels (81%), the prevalence rate was significantly higher. On average, cattle and camels were up to twice to four times older than small ruminants. Interestingly, the seroprevalence in all species was directly linked to the age of the animals, i.e. older animals had significantly higher seroprevalence rates than younger animals. The highest CCHFV seroprevalence in Mauritania was found in camels and cattle, followed by small ruminants. The large proportion of positive animals in cattle and camels might be explained by the high ages of the animals. Future CCHFV prevalence studies should at least consider the age of surveyed animals in order to avoid misinterpretations., Author summary Crimean-Congo hemorrhagic fever virus (CCHFV) is a silent threat that repeatedly causes severe hemorrhagic disease in humans who have been in close contact with livestock of endemic countries. The detection of CCHFV IgG antibodies in livestock can be a first indication whether the virus circulates in a given region and is thus a valuable diagnostic tool for determining the endemic status. Interestingly, earlier data from Mauritania showed a noticeable difference in IgG prevalence between sheep (18%) and cattle (67%). In contrast to sheep and cattle, current monitoring data on CCHFV IgG antibody presence in camels and goats in Mauritania is very limited. This study was conducted to provide a comprehensive up-to-date overview of CCHFV seroprevalences in the four most important Mauritanian livestock species (cattle, sheep, goats and camels). It attempts to highlight the role of potential risk factors responsible for deviating prevalences. In addition, we developed a camel-specific IgG ELISA, which can be used in future CCHFV seroprevalence studies. Furthermore, findings of this study contribute to a better understanding of the current epidemiological CCHFV situation in sub-Saharan Africa and which role different livestock species play regarding the viral circulation in endemic regions.

International audience; This article presents a participative and iterative qualitative risk assessment framework that can be used to evaluate the spatial variation of the risk of infectious animal disease introduction and spread on a national scale. The framework was developed through regional training action workshops and field activities. The active involvement of national animal health services enabled the identification, collection and hierarchization of risk factors. Quantitative data were collected in the field, and expert knowledge was integrated to adjust the available data at regional level. Experts categorized and combined the risk factors into ordinal levels of risk per epidemiological unit to ease implementation of risk-based surveillance in the field. The framework was used to perform a qualitative assessment of the risk of introduction and spread of foot-and-mouth disease (FMD) in Tunisia as part of a series of workshops held between 2015 and 2018. The experts in attendance combined risk factors such as epidemiological status, transboundary movements, proximity to the borders and accessibility to assess the risk of FMD outbreaks in Tunisia. Out of the 2,075 Tunisian imadas, 23 were at a very high risk of FMD introduction, mainly at the borders; and 59 were at a very high risk of FMD spread. To validate the model, the results were compared to the FMD outbreaks notified by Tunisia during the 2014 FMD epizootic. Using a spatial Poisson model, a significant alignment between the very high and high-risk categories of spread and the occurrence of FMD outbreaks was shown. The relative risk of FMD occurrence was thus 3.2 higher for imadas in the very high and high spread risk categories than for imadas in the low and negligible spread risk categories. Our results show that the qualitative risk assessment framework can be a useful decision support tool for risk-based disease surveillance and control, in particular in scarce-data environments.

Background: Crimean-Congo hemorrhagic fever virus (CCHFV) belongs to the Nairovididae family in the Orthonairovirus genus and is an emerging tick-borne virus. It is endemic in most parts of Africa, Asia, as well as southern Europe, and can cause severe hemorrhagic symptoms in humans with high fatality rates (5-30 %). Methods: Hyalomma ticks were collected from four different livestock herds (cattle and camel) from Mauritania in 2018. The tick species was determined morphologically and confirmed on a molecular level by using cytochrome oxidase 1 gene marker (CO1). For the detection of CCHFV, ticks were tested individually with a one-step multiplex real-time RT-qPCR. Subsequently, the S-segment of all positive samples were sequenced to determine the CCHFV genotype.Results: Overall, 39 of 1,523 ticks (2.56 %) collected from 63 cattle and 28 camels were tested positive for CCHFV. Three Hyalomma (H.) species were identified. The highest prevalence of CCHFV was found in Hyalomma rufipes (5.67 %; 16/282), followed by H. dromedarii (1.89 %; 23/1,214) and H. impeltatum (0 %; 0/21). Positive ticks were found on only 6 out of 91 host animals. Sequence analysis of the positive samples revealed the presence of two different CCHFV lineages (Africa I and Africa III). Conclusions: This study reveals a CCHFV prevalence of 2.56 % in Hyalomma ticks collected from camels and cattle in Mauritania. The true prevalence of unfed ticks may however be lower since a considerable number of ticks may have been passively infected during the ingestion of the blood meal by co-feeding or viremia of the host. The study shows that tick control measures should be implemented, especially in the examined areas.

Understanding spatio-temporal patterns of host mobility is a key factor to prevent and control animal and human diseases. This is utterly important in low-income countries, where animal disease epidemics have strong socio-economic impacts. In this article we analyzed a livestock mobility database, whose data have been collected by the Centre National d'Elevage et de Recherches Veterinaires (CNERV) Mauritania, to describe its patterns and temporal evolution. Data were collected through phone and face-to-face interviews in almost all the regions in Mauritania over a period of roughly two weeks during June 2015. The analysis has shown the existence of two mobility patterns throughout the year: the first related to routine movements from January to August; the second strictly connected to the religious festivity of Tabaski that in 2014 occurred at the beginning of October. These mobility patterns are different in terms of animals involved (fewer cattle and dromedaries are traded around Tabaski), the means of transportation (the volume of animals moved by truck raises around Tabaski) and destinations (most of the animals are traded nationally around Tabaski). Due to the differences between these two periods, public health officers, researchers and other stakeholders should take account of the time of the year when implementing vaccination campaigns or creating surveillance networks.

Peste des petits ruminants (PPR) is caused by a Morbillivirus (Paramyxoviridae) that infects mostly goats and sheep. Discovered in Ivory Coast in 1942, this disease is now endemic in most African countries and has spread in Asia as far as India and China1. In immunologically naïve small ruminant populations, mortality rate is around 90% among younger animals, whilst it has milder effects on older ones. PPR has a devastating effect on the economies of low-income families. A live attenuated vaccine was developed in the 1980's, providing a life-long immunity after a single injection. The global eradication of PPR is now on the agenda of the Food and Agricultural Organization of the United Nations (FAO) and World Animal Health Organization (OIE) who play a pivotal role as they aim to reach this goal before 2030 ². Mobility of live animals is the most important factors in the diffusion and in maintaining the disease endemic in West Africa. It is a complex phenomenon involving different types of movements: small ruminants' trade among Western Africa countries (http://faostat.fao.org/); transhumance from arid areas of the North to greener areas in the South and sometimes crossing frontiers; religious festivity, like Tabaski during which millions of sheep are slaughtered. With this respect, Senegal and Mauritania have developed a system of animal health certificates to track livestock movements. These data allow researchers to re-construct the mobility network at the country level, and provides hint about animal movements across their borders. To describe PPR diffusion patterns, estimate its infectious burden, and assess the effects of PPR vaccination strategies we have been developing a metapopulation model for PPR in Mauritania and Senegal. We consider a network whose nodes correspond to administrative districts, and whose links represent the animal movements between two of them. The model couples the virus transmission and small ruminant population dynamics occurring at the local (within-district) level, with the virus diffusion due to livestock mobility. The model uses different data sources. The mobility network is built on the data collected by the Mauritanian and Senegalese Veterinarian Services. Small ruminant population dynamics is calibrated on the data from previous follow-up studies implemented in Senegal 3. PPR prevalence and epidemiological data are taken from the VACNADA project (http://au-ibar.org/vacnada). We briefly present the analysis of the different data sources to provide a panoramic view of the situation in West Africa. We then present some of the results of the model, focusing on the conditions that could lead to PPR outbreaks, maintain its endemicity, or stop the epidemics.

Rift Valley Fever Outbreak, Mauritania, 2012, After a period of heavy rainfall, an outbreak of Rift Valley fever occurred in southern Mauritania during September–November 2012. A total of 41 human cases were confirmed, including 13 deaths, and 12 Rift Valley fever virus strains were isolated. Moudjeria and Temchecket Departments were the most affected areas.

During September–October 2010, an unprecedented outbreak of Rift Valley fever was reported in the northern Sahelian region of Mauritania after exceptionally heavy rainfall. Camels probably played a central role in the local amplifi cation of the virus. We describe the main clinical signs (hemorrhagic fever, icterus, and nervous symptoms) observed during the outbreak.