Maryam Diarra - Academia.edu (original) (raw)

Papers by Maryam Diarra

Journal of classification, Feb 28, 2024

International Journal of Infectious Diseases, Dec 31, 2023

Infectious Disease Modelling, Nov 30, 2023

Emerging infectious diseases, Apr 1, 2024

medRxiv (Cold Spring Harbor Laboratory), Jul 8, 2023

Objectives Africa has experienced fewer coronavirus disease 2019 (COVID-19) cases and deaths than... more Objectives Africa has experienced fewer coronavirus disease 2019 (COVID-19) cases and deaths than other regions, with a contrasting epidemiological situation between countries, raising questions regarding the determinants of disease spread in Africa. Method: We built a susceptible-exposed-infected-recovered model including COVID-19 mortality data where recovery class is structured by specific immunization and modeled by a partial di erential equation considering the opposed e ects of immunity decline and immunization. This model was applied to Tunisia, Senegal, and Madagascar. Finding: Senegal and Tunisia experienced two epidemic phases. Initially, infections emerged in naive individuals and were limited by social distancing. Variants of concern (VOCs) were also introduced. The second phase was characterized by successive epidemic waves driven by new VOCs that escaped host immunity. Meanwhile, Madagascar demonstrated a di erent profile, characterized by longer intervals between epidemic waves, increasing the pool of susceptible individuals who had lost their protective immunity. The impact of vaccination in Tunisia and Senegal on model parameters was evaluated. Interpretation: Loss of immunity and vaccination-induced immunity have played crucial role in controlling the African pandemic. Severe acute respiratory syndrome coronavirus 2 has become endemic now and will continue to circulate in African populations. However, previous infections provide significant protection against severe diseases, thus providing a basis for future vaccination strategies.

Scientific Reports

During the COVID-19 pandemic in Senegal, contact tracing was done to identify transmission cluste... more During the COVID-19 pandemic in Senegal, contact tracing was done to identify transmission clusters, their analysis allowed to understand their dynamics and evolution. In this study, we used information from the surveillance data and phone interviews to construct, represent and analyze COVID-19 transmission clusters from March 2, 2020, to May 31, 2021. In total, 114,040 samples were tested and 2153 transmission clusters identified. A maximum of 7 generations of secondary infections were noted. Clusters had an average of 29.58 members and 7.63 infected among them; their average duration was 27.95 days. Most of the clusters (77.3%) are concentrated in Dakar, capital city of Senegal. The 29 cases identified as super-spreaders, i.e., the indexes that had the most positive contacts, showed few symptoms or were asymptomatic. Deepest transmission clusters are those with the highest percentage of asymptomatic members. The correlation between proportion of asymptomatic and degree of transmis...

Frontiers in virology, Jan 30, 2023

On 10 th September 2018, the Syndromic Sentinel Surveillance network that monitors febrile illnes... more On 10 th September 2018, the Syndromic Sentinel Surveillance network that monitors febrile illnesses in all 14 regions of Senegal detected a peak of fever in the Fatick region. On 13 September 2018, 10 samples were sent to the WHO Collaborating Centre for Arboviruses and Viral Haemorrhagic Fevers at the Institut Pasteur de Dakar (IPD). Laboratory investigations revealed an epidemic of dengue 1 genotype V and dengue 3 genotype III. Fatick neighbors the Holy City of Touba where 3.5 million people from all over the word gather every year for the Grand Magal pilgrimage. This article discusses the impact of mass gatherings and their role in the recent introduction of dengue serotypes in Senegal. Dengue is now endemic in Senegal and across many countries in Africa, highlighting the need for early detection, control measures and prevention of severe dengue cases in highly connected urban settings.

Infectious Disease Modelling

Scientific Reports

The Rapid proliferation of traditional gold mining sites in the Kedougou region has led to massiv... more The Rapid proliferation of traditional gold mining sites in the Kedougou region has led to massive migration of people from neighbouring West African countries and the establishment of several small villages where poor hygiene and sanitation conditions exist. In this context, a Hepatitis E virus outbreak was reported in Kedougou in 2014 with several cases among the traditional mining workers. Herein, we described epidemiological and laboratory data collected during the outbreak’s investigation from February 2012 to November 2014. Any suspected, contact or probable case was investigated, clinical and epidemiological data were collected. In our study, sera were collected and tested for viral RNA and anti-Hepatitis E virus (HEV) IgM. Archived serum samples from Kedougou were retrospectively screened by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). A total of 65 water samples collected from ponds and wells surrounding gold panners' sites...

PLOS ONE

Background The novel coronavirus disease 2019 (COVID-19) pandemic has spread from China to the re... more Background The novel coronavirus disease 2019 (COVID-19) pandemic has spread from China to the rest of the world. Africa seems less impacted with lower number of cases and deaths than other continents. Senegal recorded its first case on March 2, 2020. We present here data collected from March 2 to October 31, 2020 in Senegal. Methods Socio-demographic, epidemiological, clinical and virological information were collected on suspected cases. To determine factors associated with diagnosed infection, symptomatic disease and death, multivariable binary logistic regression and log binomial models were used. Epidemiological parameters such as the reproduction number and growth rate were estimated. Results 67,608 suspected cases were tested by the IPD laboratories (13,031 positive and 54,577 negative). All age categories were associated with SARS-CoV-2 infection, but also patients having diabetes or hypertension or other cardiovascular diseases. With diagnosed infection, patients over 65 ye...

Emerging Microbes & Infections, 2022

ABSTRACT We report surveillance results of Cache Valley virus (CVV; Peribunyaviridae, Orthobunyav... more ABSTRACT We report surveillance results of Cache Valley virus (CVV; Peribunyaviridae, Orthobunyavirus) from 2017 to 2020 in New York State (NYS). Infection rates were calculated using the maximum likelihood estimation (MLE) method by year, region, and mosquito species. The highest infection rates were identified among Anopheles spp. mosquitoes and we detected the virus in Aedes albopictus for the first time in NYS. Based on our previous Anopheles quadrimaculatus vector competence results for nine CVV strains, we selected among them three stains for further characterization. These include two CVV reassortants (PA and 15041084) and one CVV lineage 2 strain (Hu-2011). We analyzed full genomes, compared in vitro growth kinetics and assessed vector competence of Aedes albopictus. Sequence analysis of the two reassortant strains (PA and 15041084) revealed 0.3%, 0.4%, and 0.3% divergence; and 1, 10, and 6 amino acid differences for the S, M, and L segments, respectively. We additionally found that the PA strain was attenuated in vertebrate (Vero) and mosquito (C6/36) cell culture. Furthemore, Ae. albopictus mosquitoes are competent vectors for CVV Hu-2011 (16.7–62.1% transmission rates) and CVV 15041084 (27.3–48.0% transmission rates), but not for the human reassortant (PA) isolate, which did not disseminate from the mosquito midgut. Together, our results demonstrate significant phenotypic variability among strains and highlight the capacity for Ae. albopictus to act as a vector of CVV.

Figure S1. Climatic and environmental data on Senegalese territory with a spatial resolution on 1... more Figure S1. Climatic and environmental data on Senegalese territory with a spatial resolution on 1 km2. Abbreviations: Av, Average; Min, Minimum; Max, Maximum; Dlst, Day land surface temperature; Nlst, Night land surface temperature; lc, landcover; NDVI, Normalized difference vegetation index; Host, livestock density. (PDF 308 kb)

Table S1. Culicoides data from Senegal throughout a nation-wide trapping campaign in 2012. (XLSX ... more Table S1. Culicoides data from Senegal throughout a nation-wide trapping campaign in 2012. (XLSX 15 kb)

Revue d'élevage et de médecine vétérinaire des pays tropicaux, 1998

La zone agropastorale de Tienfala-Baguinéda, située à l’est de Bamako au Mali (figure 1), couvre ... more La zone agropastorale de Tienfala-Baguinéda, située à l’est de Bamako au Mali (figure 1), couvre une superficie d’environ 1 500 km2, de part et d’autre du fleuve Niger. Le climat est de type soudanien, avec une pluviométrie moyenne de 1 037 mm/an et des températures moyennes annuelles allant de 26 à 35 °C. De récentes prospections (11) n’ont pas révélé la présence de Glossina morsitans submorsitans, sous-espèce de savane jadis présente en de très faibles densités (13). Le milieu est infesté de G. palpalis gambiensis, sous-espèce riveraine présente dans le cordon ripicole, les îlots et les galeries forestières du fleuve et de ses affluents. Cette infestation compromet l’élevage à l’intérieur de la « ceinture laitière » autour de la capitale. Le cheptel bovin, estimé à près de 40 000 têtes, est composé essentiellement de races trypanosensibles : zébus, animaux importés (Montbéliards) et des métis. L’élevage de telles races en présence de mouches tsé-tsé impose des contraintes, avec no...

Revue d'élevage et de médecine vétérinaire des pays tropicaux, 1997

Il peut être divisé en trois zones distinctes : la zone désertique au nord de l’isohyète 200 mm (... more Il peut être divisé en trois zones distinctes : la zone désertique au nord de l’isohyète 200 mm (50 p. 100 de la superficie totale), la zone sahélienne à l’est et au centre (25 p. 100 du territoire national) et la zone soudanienne à l’ouest et au sud (25 p. 100 du territoire national, avec une pluviométrie supérieure à 800 mm par an) (7) (figure 1). L’élevage constitue une activité économique importante du pays, mais ce secteur a été gravement affecté par une sécheresse qui sévit depuis plus d’une dizaine d’années. De 1982 à 1995, l’effectif du cheptel est passé de 6 663 000 à 5 708 000 têtes pour les bovins et de 12 437 000 à 13 179 000 pour les ovins-caprins. Le bétail est composé de 84 p. 100 de zébus et 16 p. 100 de taurins (trypanotolérants).

Parasites & vectors, Jan 8, 2018

In Senegal, the last epidemic of African horse sickness (AHS) occurred in 2007. The western part ... more In Senegal, the last epidemic of African horse sickness (AHS) occurred in 2007. The western part of the country (the Niayes area) concentrates modern farms with exotic horses of high value and was highly affected during the 2007 outbreak that has started in the area. Several studies were initiated in the Niayes area in order to better characterize Culicoides diversity, ecology and the impact of environmental and climatic data on dynamics of proven and suspected vectors. The aims of this study are to better understand the spatial distribution and diversity of Culicoides in Senegal and to map their abundance throughout the country. Culicoides data were obtained through a nationwide trapping campaign organized in 2012. Two successive collection nights were carried out in 96 sites in 12 (of 14) regions of Senegal at the end of the rainy season (between September and October) using OVI (Onderstepoort Veterinary Institute) light traps. Three different modeling approaches were compared: th...

Parasites & Vectors, 2014

Background: The African horse sickness epizootic in Senegal in 2007 caused considerable mortality... more Background: The African horse sickness epizootic in Senegal in 2007 caused considerable mortality in the equine population and hence major economic losses. The vectors involved in the transmission of this arbovirus have never been studied specifically in Senegal. This first study of the spatial and temporal dynamics of the Culicoides (Diptera: Ceratopogonidae) species, potential vectors of African horse sickness in Senegal, was conducted at five sites (Mbao, Parc Hann, Niague, Pout and Thies) in the Niayes area, which was affected by the outbreak. Methods: Two Onderstepoort light traps were used at each site for three nights of consecutive collection per month over one year to measure the apparent abundance of the Culicoides midges. Results: In total, 224,665 specimens belonging to at least 24 different species (distributed among 11 groups of species) of the Culicoides genus were captured in 354 individual collections. Culicoides oxystoma, Culicoides kingi, Culicoides imicola, Culicoides enderleini and Culicoides nivosus were the most abundant and most frequent species at the collection sites. Peaks of abundance coincide with the rainy season in September and October. Conclusions: In addition to C. imicola, considered a major vector for the African horse sickness virus, C. oxystoma may also be involved in the transmission of this virus in Senegal given its abundance in the vicinity of horses and its suspected competence for other arboviruses including bluetongue virus. This study depicted a site-dependent spatial variability in the dynamics of the populations of the five major species in relation to the eco-climatic conditions at each site.

BMJ Global Health, 2022

BackgroundWhen vaccines against the novel COVID-19 were available in Senegal, many questions were... more BackgroundWhen vaccines against the novel COVID-19 were available in Senegal, many questions were raised. How long should non-pharmaceutical interventions (NPIs) be maintained during vaccination roll-out? What are the best vaccination strategies?MethodsIn this study, we used an age-structured dynamic mathematical model. This model uses parameters based on SARS-CoV-2 virus, information on different types of NPIs, epidemiological and demographic data, some parameters relating to hospitalisations and vaccination in Senegal.ResultsIn all scenarios explored, the model predicts a larger third epidemic wave of COVID-19 in terms of new cases and deaths than the previous waves. In a context of limited vaccine supply, vaccination alone will not be sufficient to control the epidemic, and the continuation of NPIs is necessary to flatten the epidemic curve. Assuming 20% of the population have been vaccinated, the optimal period to relax NPIs would be a few days from the last peak. Regarding the ...

Revue d'élevage et de médecine vétérinaire des pays tropicaux, 1997

La zone agropastorale de Baguinéda-Tienfala, située à l’est de Bamako, couvre de part et d’autre ... more La zone agropastorale de Baguinéda-Tienfala, située à l’est de Bamako, couvre de part et d’autre du fleuve Niger une superficie d’environ 1 500 km2. Elle est comprise entre les parallèles 12° 24’-12° 48’ N et les méridiens 7° 30’-8° O. Le climat est de type soudanien, avec une pluviométrie annuelle moyenne de 1 037 mm et une température annuelle moyenne allant de 26 à 35 °C. Glossina palpalis gambiensis infeste le cordon ripicole, les îlots et les galeries forestières du fleuve Niger et ses affluents sur environ 416 km. Ces bandes forestières sont dominées par Syzygium guineense, Cynometra vogelii, Pterocarpus santalinoides. La savane arbustive de type soudanien est caractérisée par Vitelaria paradoxa, Parkia biglobosa, Terminalia spp. et Combretum spp. La savane herbeuse occupe le lit majeur du fleuve, avec une production fourragère moyenne de 2 500 à 3 000 kg de matière sèche par hectare. La zone d’étude comporte les forêts classées de Tienfala et de

Journal of classification, Feb 28, 2024

International Journal of Infectious Diseases, Dec 31, 2023

Infectious Disease Modelling, Nov 30, 2023

Emerging infectious diseases, Apr 1, 2024

medRxiv (Cold Spring Harbor Laboratory), Jul 8, 2023

Objectives Africa has experienced fewer coronavirus disease 2019 (COVID-19) cases and deaths than... more Objectives Africa has experienced fewer coronavirus disease 2019 (COVID-19) cases and deaths than other regions, with a contrasting epidemiological situation between countries, raising questions regarding the determinants of disease spread in Africa. Method: We built a susceptible-exposed-infected-recovered model including COVID-19 mortality data where recovery class is structured by specific immunization and modeled by a partial di erential equation considering the opposed e ects of immunity decline and immunization. This model was applied to Tunisia, Senegal, and Madagascar. Finding: Senegal and Tunisia experienced two epidemic phases. Initially, infections emerged in naive individuals and were limited by social distancing. Variants of concern (VOCs) were also introduced. The second phase was characterized by successive epidemic waves driven by new VOCs that escaped host immunity. Meanwhile, Madagascar demonstrated a di erent profile, characterized by longer intervals between epidemic waves, increasing the pool of susceptible individuals who had lost their protective immunity. The impact of vaccination in Tunisia and Senegal on model parameters was evaluated. Interpretation: Loss of immunity and vaccination-induced immunity have played crucial role in controlling the African pandemic. Severe acute respiratory syndrome coronavirus 2 has become endemic now and will continue to circulate in African populations. However, previous infections provide significant protection against severe diseases, thus providing a basis for future vaccination strategies.

Scientific Reports

During the COVID-19 pandemic in Senegal, contact tracing was done to identify transmission cluste... more During the COVID-19 pandemic in Senegal, contact tracing was done to identify transmission clusters, their analysis allowed to understand their dynamics and evolution. In this study, we used information from the surveillance data and phone interviews to construct, represent and analyze COVID-19 transmission clusters from March 2, 2020, to May 31, 2021. In total, 114,040 samples were tested and 2153 transmission clusters identified. A maximum of 7 generations of secondary infections were noted. Clusters had an average of 29.58 members and 7.63 infected among them; their average duration was 27.95 days. Most of the clusters (77.3%) are concentrated in Dakar, capital city of Senegal. The 29 cases identified as super-spreaders, i.e., the indexes that had the most positive contacts, showed few symptoms or were asymptomatic. Deepest transmission clusters are those with the highest percentage of asymptomatic members. The correlation between proportion of asymptomatic and degree of transmis...

Frontiers in virology, Jan 30, 2023

On 10 th September 2018, the Syndromic Sentinel Surveillance network that monitors febrile illnes... more On 10 th September 2018, the Syndromic Sentinel Surveillance network that monitors febrile illnesses in all 14 regions of Senegal detected a peak of fever in the Fatick region. On 13 September 2018, 10 samples were sent to the WHO Collaborating Centre for Arboviruses and Viral Haemorrhagic Fevers at the Institut Pasteur de Dakar (IPD). Laboratory investigations revealed an epidemic of dengue 1 genotype V and dengue 3 genotype III. Fatick neighbors the Holy City of Touba where 3.5 million people from all over the word gather every year for the Grand Magal pilgrimage. This article discusses the impact of mass gatherings and their role in the recent introduction of dengue serotypes in Senegal. Dengue is now endemic in Senegal and across many countries in Africa, highlighting the need for early detection, control measures and prevention of severe dengue cases in highly connected urban settings.

Infectious Disease Modelling

Scientific Reports

The Rapid proliferation of traditional gold mining sites in the Kedougou region has led to massiv... more The Rapid proliferation of traditional gold mining sites in the Kedougou region has led to massive migration of people from neighbouring West African countries and the establishment of several small villages where poor hygiene and sanitation conditions exist. In this context, a Hepatitis E virus outbreak was reported in Kedougou in 2014 with several cases among the traditional mining workers. Herein, we described epidemiological and laboratory data collected during the outbreak’s investigation from February 2012 to November 2014. Any suspected, contact or probable case was investigated, clinical and epidemiological data were collected. In our study, sera were collected and tested for viral RNA and anti-Hepatitis E virus (HEV) IgM. Archived serum samples from Kedougou were retrospectively screened by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). A total of 65 water samples collected from ponds and wells surrounding gold panners' sites...

PLOS ONE

Background The novel coronavirus disease 2019 (COVID-19) pandemic has spread from China to the re... more Background The novel coronavirus disease 2019 (COVID-19) pandemic has spread from China to the rest of the world. Africa seems less impacted with lower number of cases and deaths than other continents. Senegal recorded its first case on March 2, 2020. We present here data collected from March 2 to October 31, 2020 in Senegal. Methods Socio-demographic, epidemiological, clinical and virological information were collected on suspected cases. To determine factors associated with diagnosed infection, symptomatic disease and death, multivariable binary logistic regression and log binomial models were used. Epidemiological parameters such as the reproduction number and growth rate were estimated. Results 67,608 suspected cases were tested by the IPD laboratories (13,031 positive and 54,577 negative). All age categories were associated with SARS-CoV-2 infection, but also patients having diabetes or hypertension or other cardiovascular diseases. With diagnosed infection, patients over 65 ye...

Emerging Microbes & Infections, 2022

ABSTRACT We report surveillance results of Cache Valley virus (CVV; Peribunyaviridae, Orthobunyav... more ABSTRACT We report surveillance results of Cache Valley virus (CVV; Peribunyaviridae, Orthobunyavirus) from 2017 to 2020 in New York State (NYS). Infection rates were calculated using the maximum likelihood estimation (MLE) method by year, region, and mosquito species. The highest infection rates were identified among Anopheles spp. mosquitoes and we detected the virus in Aedes albopictus for the first time in NYS. Based on our previous Anopheles quadrimaculatus vector competence results for nine CVV strains, we selected among them three stains for further characterization. These include two CVV reassortants (PA and 15041084) and one CVV lineage 2 strain (Hu-2011). We analyzed full genomes, compared in vitro growth kinetics and assessed vector competence of Aedes albopictus. Sequence analysis of the two reassortant strains (PA and 15041084) revealed 0.3%, 0.4%, and 0.3% divergence; and 1, 10, and 6 amino acid differences for the S, M, and L segments, respectively. We additionally found that the PA strain was attenuated in vertebrate (Vero) and mosquito (C6/36) cell culture. Furthemore, Ae. albopictus mosquitoes are competent vectors for CVV Hu-2011 (16.7–62.1% transmission rates) and CVV 15041084 (27.3–48.0% transmission rates), but not for the human reassortant (PA) isolate, which did not disseminate from the mosquito midgut. Together, our results demonstrate significant phenotypic variability among strains and highlight the capacity for Ae. albopictus to act as a vector of CVV.

Figure S1. Climatic and environmental data on Senegalese territory with a spatial resolution on 1... more Figure S1. Climatic and environmental data on Senegalese territory with a spatial resolution on 1 km2. Abbreviations: Av, Average; Min, Minimum; Max, Maximum; Dlst, Day land surface temperature; Nlst, Night land surface temperature; lc, landcover; NDVI, Normalized difference vegetation index; Host, livestock density. (PDF 308 kb)

Table S1. Culicoides data from Senegal throughout a nation-wide trapping campaign in 2012. (XLSX ... more Table S1. Culicoides data from Senegal throughout a nation-wide trapping campaign in 2012. (XLSX 15 kb)

Revue d'élevage et de médecine vétérinaire des pays tropicaux, 1998

La zone agropastorale de Tienfala-Baguinéda, située à l’est de Bamako au Mali (figure 1), couvre ... more La zone agropastorale de Tienfala-Baguinéda, située à l’est de Bamako au Mali (figure 1), couvre une superficie d’environ 1 500 km2, de part et d’autre du fleuve Niger. Le climat est de type soudanien, avec une pluviométrie moyenne de 1 037 mm/an et des températures moyennes annuelles allant de 26 à 35 °C. De récentes prospections (11) n’ont pas révélé la présence de Glossina morsitans submorsitans, sous-espèce de savane jadis présente en de très faibles densités (13). Le milieu est infesté de G. palpalis gambiensis, sous-espèce riveraine présente dans le cordon ripicole, les îlots et les galeries forestières du fleuve et de ses affluents. Cette infestation compromet l’élevage à l’intérieur de la « ceinture laitière » autour de la capitale. Le cheptel bovin, estimé à près de 40 000 têtes, est composé essentiellement de races trypanosensibles : zébus, animaux importés (Montbéliards) et des métis. L’élevage de telles races en présence de mouches tsé-tsé impose des contraintes, avec no...

Revue d'élevage et de médecine vétérinaire des pays tropicaux, 1997

Il peut être divisé en trois zones distinctes : la zone désertique au nord de l’isohyète 200 mm (... more Il peut être divisé en trois zones distinctes : la zone désertique au nord de l’isohyète 200 mm (50 p. 100 de la superficie totale), la zone sahélienne à l’est et au centre (25 p. 100 du territoire national) et la zone soudanienne à l’ouest et au sud (25 p. 100 du territoire national, avec une pluviométrie supérieure à 800 mm par an) (7) (figure 1). L’élevage constitue une activité économique importante du pays, mais ce secteur a été gravement affecté par une sécheresse qui sévit depuis plus d’une dizaine d’années. De 1982 à 1995, l’effectif du cheptel est passé de 6 663 000 à 5 708 000 têtes pour les bovins et de 12 437 000 à 13 179 000 pour les ovins-caprins. Le bétail est composé de 84 p. 100 de zébus et 16 p. 100 de taurins (trypanotolérants).

Parasites & vectors, Jan 8, 2018

In Senegal, the last epidemic of African horse sickness (AHS) occurred in 2007. The western part ... more In Senegal, the last epidemic of African horse sickness (AHS) occurred in 2007. The western part of the country (the Niayes area) concentrates modern farms with exotic horses of high value and was highly affected during the 2007 outbreak that has started in the area. Several studies were initiated in the Niayes area in order to better characterize Culicoides diversity, ecology and the impact of environmental and climatic data on dynamics of proven and suspected vectors. The aims of this study are to better understand the spatial distribution and diversity of Culicoides in Senegal and to map their abundance throughout the country. Culicoides data were obtained through a nationwide trapping campaign organized in 2012. Two successive collection nights were carried out in 96 sites in 12 (of 14) regions of Senegal at the end of the rainy season (between September and October) using OVI (Onderstepoort Veterinary Institute) light traps. Three different modeling approaches were compared: th...

Parasites & Vectors, 2014

Background: The African horse sickness epizootic in Senegal in 2007 caused considerable mortality... more Background: The African horse sickness epizootic in Senegal in 2007 caused considerable mortality in the equine population and hence major economic losses. The vectors involved in the transmission of this arbovirus have never been studied specifically in Senegal. This first study of the spatial and temporal dynamics of the Culicoides (Diptera: Ceratopogonidae) species, potential vectors of African horse sickness in Senegal, was conducted at five sites (Mbao, Parc Hann, Niague, Pout and Thies) in the Niayes area, which was affected by the outbreak. Methods: Two Onderstepoort light traps were used at each site for three nights of consecutive collection per month over one year to measure the apparent abundance of the Culicoides midges. Results: In total, 224,665 specimens belonging to at least 24 different species (distributed among 11 groups of species) of the Culicoides genus were captured in 354 individual collections. Culicoides oxystoma, Culicoides kingi, Culicoides imicola, Culicoides enderleini and Culicoides nivosus were the most abundant and most frequent species at the collection sites. Peaks of abundance coincide with the rainy season in September and October. Conclusions: In addition to C. imicola, considered a major vector for the African horse sickness virus, C. oxystoma may also be involved in the transmission of this virus in Senegal given its abundance in the vicinity of horses and its suspected competence for other arboviruses including bluetongue virus. This study depicted a site-dependent spatial variability in the dynamics of the populations of the five major species in relation to the eco-climatic conditions at each site.

BMJ Global Health, 2022

BackgroundWhen vaccines against the novel COVID-19 were available in Senegal, many questions were... more BackgroundWhen vaccines against the novel COVID-19 were available in Senegal, many questions were raised. How long should non-pharmaceutical interventions (NPIs) be maintained during vaccination roll-out? What are the best vaccination strategies?MethodsIn this study, we used an age-structured dynamic mathematical model. This model uses parameters based on SARS-CoV-2 virus, information on different types of NPIs, epidemiological and demographic data, some parameters relating to hospitalisations and vaccination in Senegal.ResultsIn all scenarios explored, the model predicts a larger third epidemic wave of COVID-19 in terms of new cases and deaths than the previous waves. In a context of limited vaccine supply, vaccination alone will not be sufficient to control the epidemic, and the continuation of NPIs is necessary to flatten the epidemic curve. Assuming 20% of the population have been vaccinated, the optimal period to relax NPIs would be a few days from the last peak. Regarding the ...

Revue d'élevage et de médecine vétérinaire des pays tropicaux, 1997

La zone agropastorale de Baguinéda-Tienfala, située à l’est de Bamako, couvre de part et d’autre ... more La zone agropastorale de Baguinéda-Tienfala, située à l’est de Bamako, couvre de part et d’autre du fleuve Niger une superficie d’environ 1 500 km2. Elle est comprise entre les parallèles 12° 24’-12° 48’ N et les méridiens 7° 30’-8° O. Le climat est de type soudanien, avec une pluviométrie annuelle moyenne de 1 037 mm et une température annuelle moyenne allant de 26 à 35 °C. Glossina palpalis gambiensis infeste le cordon ripicole, les îlots et les galeries forestières du fleuve Niger et ses affluents sur environ 416 km. Ces bandes forestières sont dominées par Syzygium guineense, Cynometra vogelii, Pterocarpus santalinoides. La savane arbustive de type soudanien est caractérisée par Vitelaria paradoxa, Parkia biglobosa, Terminalia spp. et Combretum spp. La savane herbeuse occupe le lit majeur du fleuve, avec une production fourragère moyenne de 2 500 à 3 000 kg de matière sèche par hectare. La zone d’étude comporte les forêts classées de Tienfala et de