Persisting and emerging infectious diseases in West Africa
Team 3 of UMR D 257 Vectors – Tropical and Mediterranean Infections (VITROME)
Aix-Marseille University (AMU), Institut de Recherche pour le Développement (IRD) – French Military Health Service (SSA)
The Team 3 of VITROME is located in Dakar, Sénégal.
- ABOTSI Kokou
- BA El Hadj
- BA Fambaye
- BALDE Omar
- BARBOZA Louis
- BASSENE Hubert
- BOUGANALI Charles
- DIAGNE Nafissatou
- DIALLO Aldiouma
- DIATTA Georges
- DIOUF Papa Niokhor
- DOUCOURE Souleymane
- FAYE Adiouma
- MANE Youssouph
- NDIAYE Ousmane
- NDIAYE Prosper
- NDIAYE Emilie
- SENGHOR Paul
- SOW Doudou
- SOW Mouhamadou Baba
- TOURE Malick
SCIENTIFIC STRATEGY AND PROSPECTS
The main objectives of the team for 2018-2022 will be 1) Studies of identifications, measurement and epidemiological analysis of determinants for human resistance to malaria, 2) Studies of trends in mortality rates attributable to malaria and their relationship to the malaria control interventions, 3) Studies of vector-borne infectious tropical diseases and medical entomology, 4) Studies of causes of fever and emerging pathogens biodiversity in Senegal, 5) Studies of urogenital schistosomiasis by Schistosoma haematobium. This program is based on six Health and Demographic Surveillance Systems (HDSS) in Senegal (Bambey/Mbour/Fatick 602 000 inhabitants, Niakhar 47 000, Mlomp 9 000, Bandafassi 13 000 and Dielmo/Ndiop 900) and a regional network in Western Africa. This work provides the Ministry of Health and the scientific community with new data regarding the etiology, diagnosis, and treatment of infectious tropical diseases.
a) Identifications, measurement and epidemiological analysis of determinants for human resistance to malaria.
This project began in 1990 in Dielmo and in 1993 in Ndiop. Starting from personal biological, clinical and epidemiological history of the 900 inhabitants daily monitored by IRD and Institut Pasteur, we described individual heterogeneous responses to infection and disease, searched biological and epidemiological inborn or acquired determinants, quantified and modelized their importance. Data and samples acquired are also used to contribute to the development of an anti-malaria vaccine, new therapeutic or preventive strategies. This project that is unique in the malaria research field and that will still be studied in the following years.
b) Artenusate-amodiquine association for malaria treatment in Senegal: evaluation of the impact on death causes and death rates
This project started in 2006 when Senegalese Ministry of Health implemented the association artenusate-amodiaquine for treatment of malaria in all dispensaries in Senegal. Therapeutic associations have now been substitute to chloroquine. Their impact on mortality, morbidity and disease transmission of malaria has to be evaluated in Mlomp, Dielmo, Ndiop, Niakhar and Bandafassi. At the same time, other death-causes in children and adults have to be investigated.
c) Entomology activies
The current use of LLIN at the level of Dielmo village showed the possibility to control malaria. One of our main objective is to eliminate residual malaria transmission in Dielmo. Susceptiility of insecticide resistant Anopheles to Plasmodium falciparum will be inestigated and the risk associated with this phenomenon in relationship to the use of LLIN in Dielmo and Ndiop. Additional sociological and anthropological data on human behaviour will be collected. These data will be used to assess (i) the risk of setbacks in malaria control and (ii) further, if the risk of malaria transmission is increased due to insecticide resistant mosquitoes.
We describe a bacterium of the genus Asaia (α-proteobacterium), which stably associates with the microbiota of An gambiae s.l. and An funestus, vectors of malaria in Dielmo, Ndiop villages, Bandafassi and Tombrokoto. Asaia sp. was isolated from Anopheles gambiae from Senegal. In the future we consider investigating the source of Asaia sp. GD01 in Dielmo and Ndiop, the contamination of anopheles, the transmission of the bacterium to the generation, the negative action in the development of P. falciparum in the mosquito.
In African countries, the recent reductions in morbidity due to malaria highlight the importance of assessing the rates of other fever-causing agents when health care is requested. Understanding the etiology of a fever is critical for guiding treatment and policies. Our team established a platform or network of sentinel systems that was developed for the molecular detection of emerging pathogens in febrile patients in rural dispensaries in Senegal. This work provides the Ministry of Health and the scientific community with new data regarding the etiology, diagnosis, and treatment of fever. In parallel to our activities on emerging infectious diseases, several major research fields appear important to develop:
a) Vaginal self-sampling and miscarriage: We have demonstrated the acceptability of these self-sampling in rural areas, we propose at short term, to perform a study on the causes of miscarriage.
b) Malnutrition and gastrointestinal microbiota: This study will compare the gastrointestinal microbiota of malnourished children and control children and the microbiota of women breastfeeding milk for malnourished children and children witnesses.
c) Evaluation promotion of personal hygiene in the prevention of infectious diseases in rural Senegal: This major study will allow us to evaluate both the soap influence on the occurrence of infectious syndrome correlating microbial composition.
d) Doxycycline Trial on non malaria fever in Senegal: This is a pragmatic clinical trial comparing two products (amoxicillin and doxycycline) already on the market to take in charge febrile infectious disease.
e) Cross sectional survey on the burden and impacts of chronic hepatitis B virus infection in Senegal: Study evaluation of the extent and consequences of chronic infection with hepatitis B (HBV) onliving conditions of the people in rural households in West African countries with highendemicity, Senegal. Data collected will provide information on the feasibility of screening for HBV at home in rural Africa Saharan and decentralized management of chronic HBV carriers.
f) Neonatal Vaccination agains hepatitis B in Africa: NéoVAC: In 2009, WHO recommended the vaccine against hepatitis B to all newborns within 24 hours after birth to prevent perinatal and horizontal early transmission. This recommendation was reconfirmed in the latest recommendations WHO issued in March 2015 for the prevention and the treatment of infection with Hepatitis B. This study will allow us to evaluate this recommendation and provide information on the feasibility in rural context.
g) Use of innovative tools for the diagnosis of parasitic diseases in Senegal: In collaboration with the University of Dakar (UCAD, Senegal), we aim to compare the performance of real time PCR (qPCR) systems to microscopic examination in the detection of intestinal parasites. We wish also to test the MALDI TOF MS use to differenciate urine infected or nor with Schistosomia spp. parasites, that represent a major public health problem in Sub-Saharan Africa (JEAI-IRD funded from 2018 to 2020).