Quality assessment of malaria microscopic diagnosis at the Aristide Le Dantec University Hospital of Dakar, Senegal, in 2020.

BACKGROUND: Following WHO guidelines, microscopy is the gold standard for malaria diagnosis in endemic countries. The Parasitology-Mycology laboratory (LPM) is the National Reference Laboratory and is currently undergoing ISO 15189 accreditation. In this context, we assessed the performance of the laboratory by confirming the reliability and the accuracy of results obtained in accordance with the requirements of the ISO 15189 standards. This study aimed to verify the method of microscopic diagnosis of malaria at the LPM, in the Aristide Le Dantec hospital (HALD) in Dakar, Senegal. METHODS: This is a validation/verification study conducted from June to August 2020. Twenty (20) microscopic slides of thick/thin blood smear with known parasite densities (PD) selected from the Cheick Anta Diop University malaria slide bank in Dakar were used for this assessment. Six (6) were used to assess microscopists' ability to determine PD and fourteen (14) slides were used for detection (positive vs negative) and identification of parasites. Four (4) LPM-HALD microscopists read and recorded their results on prepared sheets. Data analysis was done with Microsoft Excel 2010 software. RESULTS: A minimum threshold of 50% concordance was used for comparison. Of the twenty (20) slides read, 100% concordance was obtained on eight (8) detection (positive vs negative) slides. Four (4) out of the six (6) parasite density evaluation slides obtained a concordance of less than 50%. Thirteen (13) out of the fourteen (14) identification slides obtained a concordance greater than 50%. Only one (1) identification slide obtained zero agreement from the microscopists. For species identification a concordance greater than 80% was noted and the microscopists obtained scores between 0.20 and 0.4 on a scale of 0 to 1 for parasite density reading. The microscopists obtained 100% precision, sensitivity, specificity and both negative and positive predictive values. CONCLUSION: This work demonstrated that the microscopic method of malaria diagnosis used in the LPM/HALD is in accordance with the requirements of WHO and ISO 15189. Further training of microscopists may be needed to maintain competency.

Investigating the etiologies of non-malarial febrile illness in Senegal using metagenomic sequencing.

The worldwide decline in malaria incidence is revealing the extensive burden of non-malarial febrile illness (NMFI), which remains poorly understood and difficult to diagnose. To characterize NMFI in Senegal, we collected venous blood and clinical metadata in a cross-sectional study of febrile patients and healthy controls in a low malaria burden area. Using 16S and untargeted sequencing, we detected viral, bacterial, or eukaryotic pathogens in 23% (38/163) of NMFI cases. Bacteria were the most common, with relapsing fever Borrelia and spotted fever Rickettsia found in 15.5% and 3.8% of cases, respectively. Four viral pathogens were found in a total of 7 febrile cases (3.5%). Sequencing also detected undiagnosed Plasmodium, including one putative P. ovale infection. We developed a logistic regression model that can distinguish Borrelia from NMFIs with similar presentation based on symptoms and vital signs (F1 score: 0.823). These results highlight the challenge and importance of improved diagnostics, especially for Borrelia, to support diagnosis and surveillance.

Improving diagnosis of non-malarial fevers in Senegal: Borrelia and the contribution of tick-borne bacteria.

The worldwide decline in malaria incidence is revealing the extensive burden of non-malarial febrile illness (NMFI), which remains poorly understood and difficult to diagnose. To characterize NMFI in Senegal, we collected venous blood and clinical metadata from febrile patients and healthy controls in a low malaria burden area. Using 16S and unbiased sequencing, we detected viral, bacterial, or eukaryotic pathogens in 29% of NMFI cases. Bacteria were the most common, with relapsing fever Borrelia and spotted fever Rickettsia found in 15% and 3.7% of cases, respectively. Four viral pathogens were found in a total of 7 febrile cases (3.5%). Sequencing also detected undiagnosed Plasmodium, including one putative P. ovale infection. We developed a logistic regression model to distinguish Borrelia from NMFIs with similar presentation based on symptoms and vital signs. These results highlight the challenge and importance of improved diagnostics, especially for Borrelia, to support diagnosis and surveillance.

Profile of multidrug-resistant clinical bacterial isolates at the National Hospital of Zinder (NHZ), Niger Republic in 2021

Background: Today, bacterial resistance is a public health challenge throughout the world, and infections caused by resistant bacteria are associated with increased morbidity, mortality and health care costs. The objective of this descriptive study is to determine the prevalence and distribution of multi-drug resistant (MDR) clinical bacteria isolates at the National Hospital of Zinder, Niger Republic in 2021. Methodology: We conducted a descriptive cross-sectional study of in- and out-patients from whose clinical samples' bacteria were isolated at the bacteriology unit of the laboratory. Bacteria were isolated from the clinical samples following standard aerobic cultures and identified using conventional biochemical test schemes. Antibiotic susceptibility testing (AST) was performed by the agar disk diffusion technique, and categorization of the isolates into sensitive, intermediate or resistant was done according to the recommendations of the Antibiogram Committee of the French Society of Microbiology (CA-SFM) 2020 version 1.2. MDR was defined as resistance to at least one antibiotic in three or more categories, while selected MDR bacteria such as ESBL was identified using double disk synergy test, and MRSA by cefoxitin disk diffusion test. Results: Seventy-seven (6.7%) bacterial species were isolated from 1153 clinical samples processed at the bacteriology unit of the hospital laboratory between June and December 2021, of which 65.0% (50/77) were members of the order Enterobacteriales. Escherichia coli represented 40.3% (40/77) of the isolated bacteria, Staphylococcus aureus 13.0% (10/77) and Pseudomonas aeruginosa 11.7% (9/77). The overall prevalence of MDR was 44.2% (34/77), including 61.8% (21/34) ESBL-producing Enterobacteriales (ESBL-E), 26.5% (9/34) multi-resistant P. aeruginosa and 11.7% (4/34) MRSA, with 67.6% (23/34) of the MDR isolates from outpatients. Resistance rates of the Enterobacteriales to ciprofloxacin, gentamicin, amikacin and imipenem were 62.0%, 52.0%, 38.0% and 8.0% respectively. Resistance rates of P. aeruginosa were 100.0%, 88.9%, 77.8%, 33.3%, 22.2%, and 22.2% respectively to ceftazidime, ticarcillin, imipenem, ciprofloxacin, levofloxacin, and amikacin. Resistance rates of S. aureus were 100.0%, 50.0%, 40.0%, 10.0%, 0% and 0% to penicillin G,erythromycin, cefoxitin, tetracycline, fusidic acid, and chloramphenicol respectively. ESBL-E were 47.6%,85.7% and 0% resistant to amikacin, ciprofloxacin and imipenem, and MRSA resistance rates were 75.0%, 75.0%, 50.0% and 0% to erythromycin, tetracycline, gentamicin, and chloramphenicol respectively. Conclusion: This study reports high prevalence of MDR bacteria, mainly ESBL-E, with concerning high resistance to carbapenem. Rational use of antibiotics and implementation of surveillance system for MDR bacteria must be implemented in order to limit the emergence and spread of MDR bacteria in Niger Republic.

Genomic investigation of a dengue virus outbreak in Thiès, Senegal, in 2018.

Dengue virus is a major and rapidly growing public health concern in tropic and subtropic regions across the globe. In late 2018, Senegal experienced its largest dengue virus outbreak to date, covering several regions. However, little is known about the genetic diversity of dengue virus (DENV) in Senegal. Here we report complete viral genomes from 17 previously undetected DENV cases from the city of Thiès. In total we identified 19 cases of DENV in a cohort of 198 individuals with fever collected in October and November 2018. We detected 3 co-circulating serotypes; DENV 3 was the most frequent accounting for 11/17 sequences (65%), 4 (23%) were DENV2 and 2 (12%) were DENV1. Sequences were most similar to recent sequences from West Africa, suggesting ongoing local circulation of viral populations; however, detailed inference is limited by the scarcity of available genomic data. We did not find clear associations with reported clinical signs or symptoms, highlighting the importance of testing for diagnosing febrile diseases. Overall, these findings expand the known range of DENV in Senegal, and underscore the need for better genomic characterization of DENV in West Africa.

[Clinical and Therapeutic Profile and Outcomes of Patients with Tuberculosis at the Regional Hospital of Tahoua, Republic of the Niger]. / Profil clinique, thérapeutique et évolutif de la tuberculose au centre hospitalier régional (CHR) de Tahoua, république du Niger.

This study aims to describe the epidemiological, clinical, therapeutic characteristics of patients followed for tuberculosis at the Regional Hospital Center of Tahoua (Niger) as well as their outcomes.We conducted a retrospective and descriptive study from the medical records of patients followed for tuberculosis between January 1, 2017 and December 31, 2019. A total of 465 patients were included in the present study (304 men and 161 women; mean age: 30 years). Patients coming from urban areas represented 51% of the cases. Bacteriologically confirmed pulmonary tuberculosis represented 63% of the cases, 15% of clinically diagnosed pulmonary tuberculosis and 22% of extrapulmonary tuberculosis including Pott's disease. The HIV testing rate was 97.8%. Tuberculosis-HIV association represented 13% of the cases. The therapeutic success was 90.5%. The lethality rate was 5.2% (24/465). Among 24 patients who died, three had tuberculosis-HIV association.

L'objectif de cette étude était de décrire le profil clinique, thérapeutique et évolutif des patients suivis pour tuberculose (TB) au centre hospitalier régional de Tahoua (Niger). Nous avons mené une étude rétrospective, descriptive à partir des dossiers des patients suivis pour TB entre le 1er janvier 2017 et le 31 décembre 2019. Au total, 465 patients ont été inclus dans la présente étude (304 hommes et 161 femmes, âge moyen : 30 ans). Les patients provenant du milieu urbain représentaient 51 % des cas. La TB pulmonaire confirmée bactériologiquement représentait 63 % des cas, la TB pulmonaire cliniquement diagnostiquée 15 %, la TB extrapulmonaire, notamment le mal de Pott, 22 %. L'association TB­VIH représentait 13 % des cas. Le succès thérapeutique était de 90,5 %. Le taux de létalité était de 5,2 % (24/465). Parmi les 24 patients décédés, trois présentaient l'association TB­VIH.

De la conjonctivite à l'ulcère de Mooren : errance diagnostique ou insuffisance des spécialistes

Nous rapportons une observation d'un homme âgé de 25 ans, mélanoderme sans antécédent médico-chirurgical connu, qui a consulté pour douleur oculaire,larmoiement, baisse de l'acuité visuelle, photophobie évoluant depuis environ huit mois, l'examen ophtalmologique note une hyperhémie conjonctivale, une ulcération cornéenne marginale compliquée de perforation cornéenne avec hernie de l'iris rongeant la moitié de la cornée, une excavation papillaire asymétrique.Le diagnostic d'ulcère de Mooren bilatéral est fortement suspecté, puis retenu sur la base d'argument épidémiologique ; clinique ophtalmologique (kératite ulcéreuse chronique inflammatoire qui affecte initialement la périphérie de la cornée, avec progression circonférentielle et centrale, puis perforation) ; paraclinique (la négativité de tous les examens complémentaires : les facteurs rhumatoïdes, les sérologies de l'hépatite B, C, VIH et de la syphilis, l'examen parasitologique des selles, la protéinurie de 24 h …) mais aussi après avoir exclu un certain nombre de diagnostics,notamment les maladies systémiques, les maladies infectieuses, les atteintes traumatiques des yeux.La collaboration entre ophtalmologiste et interniste a abouti à la mise en route immédiate d'un traitement à base de corticothérapie locale, d'antibiothérapie et des topiques locaux. L'évolution a été favorable avec récupération progressive de l'acuité visuelle au niveau des deux yeux deux semaines après la mise en route du traitement

A geospatial dataset of inland valleys in four zones in Benin, Sierra Leone and Mali.

The dataset described in this data article represents four agricultural zones in West-Africa that are located in three countries: Benin, Mali and Sierra Leone. The dataset was created through a research collaboration between the Africa Rice Center (AfricaRice), Sierra Leone Agricultural Research Institute (SLARI) and the Institute for Rural Economy (IER). The dataset was compiled to investigate the potential for rice production in inland valleys of the three countries. The results of the investigation were published in Dossou-Yovo et al. (2017) and Djagba et al. (2018). The dataset describes the biophysical and socioeconomic conditions of 499 inland valleys in the four agricultural zones. In each inland valley data were collected through a focus group interview with a minimum of three farmers. In 499 interviews a total of 7496 farmers participated. The location of each inland valley was determined with handheld GPS devices. The geographic locations were used to extract additional parameters from digital maps on soils, elevation, population density, rainfall, flow accumulation, and distances to roads, market places, rice mills, chemical input stores, and settlements. The dataset contains 65 parameters in four themes (location, biophysical characteristics, socioeconomic characteristics, and inland valley land development and use). The GPS coordinates indicate the location of an inland valley, but they do not lead to the location of individual fields of farmers that were interviewed. The dataset is publicly shared as Supplementary data to this data article.

A geospatial database of drought occurrence in inland valleys in Mali, Burkina Faso and Nigeria.

The data described in this article are related to drought occurrence in inland valleys and farmers adaptation strategies. The data were collected in 300 inland valleys distributed in 14 regions of West Africa. The data were collected in two phases. In the first phase, 300 inland valleys were identified in 14 regions and their locations were determined with handheld GPS devices. Questionnaires and informal interviews were administered to inland valleys users to collect data on physical and socio-economic characteristics, hydrology, farmers experience with drought affecting rice production in inland valleys and adaptation strategies. In the second phase, the locations of the inland valleys were imported in a GIS environment and were used to extract additional parameters on soil characteristics and water demand from the Shuttle Radar Topography Mission (SRTM), Africa Soil Information Service (africasoils.net) and POWER database (http://power.larc.nasa.gov). In total, the dataset contains 41 variables divided into seven themes: farmers' experience with drought, adaptive management of rice farmers to drought, physical characteristics, hydrology, management practices, socio-economic characteristics and weather data of inland valleys.

Non-traumatic acute peritonitis in children: causes and prognosis in 226 patients at the National Hospital of Zinder, Niger.

To report etiological and prognostic characteristics of acute peritonitis in children. This retrospective study reviewed the records for a 30-month period (January 2013-June 2015) at Zinder National Hospital (Niger) of all children between the ages of 0-15 years who underwent surgery for non-traumatic acute peritonitis. Statistical tests were performed, with significance defined by a P-value < 5 %. Acute peritonitis accounted for 62.12 % (226/358) of all emergency gastrointestinal surgery in children. Their median age was 10 years (range: 0-15 years), with almost two-thirds of them male (n=148). Ileal perforation, presumably due to typhoid fever, was the main cause (n=153), with acute appendicular peritonitis in second place, accounting for 25.22 % (n=57) of cases. Gastrointestinal ostomy was performed in 101 patients (44.7 %) and an appendectomy in 56 (24.8 %). The average length of stay was 10.9±3.6 days. Postoperative complications, defined by the Clavien-Dindo classification, occurred in 46.5 % of these procedures (n=105). Surgical site infections were recorded in 66 cases. Overall mortality was 13.7 % (n=31) and was statistically associated with an American Society of Anesthesiologists (ASA) score of IV (OR = 3,32 : 1,07-10,27 ; P = 0,037) and Mannheim Peritonitis Index (MPI) ≥ 26 (OR = 44,68 : 10,17 - 196,32 ; P = 0,000), time to admission (OR = 4,626 : 1,39 - 15,34, P = 0,012), and time to surgery in hours (OR = 4,59 : 1,60 - 13,18 ; P = 0,0046). In Niger, perforation apparently due to typhoid is the main cause of peritonitis in children. Mortality is associated with an ASA score of IV, Mannheim Peritonitis Index ≥ 26, time to admission, and time to surgery.

Serotype Distribution and Antimicrobial Sensitivity Profile of Streptococcus pneumoniae Carried in Healthy Toddlers before PCV13 Introduction in Niamey, Niger.

BACKGROUND: To mitigate the burden of pneumococcal infections in Niger, a 13-valent pneumococcal vaccine, PCV13, was introduced for routine child vaccination in July 2014. In order to provide pre-vaccine baseline data and allow appreciation of changes on carriage due to vaccination, we analyzed retrospectively pneumococcal isolates obtained from healthy, 0 to 2 year old children prior to the vaccine introduction. METHODS: From June 5, 2007, to May 26, 2008, 1200 nasopharyngeal swabs were collected from healthy 0 to 2 year old children and analyzed by standard microbiological methods. Serotyping was done by SM-PCR and the data were analyzed with R version 2.15.0 (2012-03-30). RESULTS: Streptococcus pneumoniae was detected in 654/1200 children (54.5%) among whom 339 (51.8%) were males. The ages of the study subjects varied from few days to 26 months (mean = 7.1, median = 6, 95% CI [6.8-7.4]). Out of 654 frozen isolates, 377 (54.8%) were able to be re-grown and analyzed. In total, 32 different serogroups/serotypes were detected of which, the most prevalent were 6/(6A/6B/6C/6D) (15.6%), 23F (10.6%), 19F (9.3%), 14 (9%), 19A (5.6%), 23B (4.0%), 25F/38 (3.7%), 18/(18A/18B/18C/18F) (2.9%) and PCR non-typeable (16.4%). Eleven serogroups/serotypes accounting for 57.3% (216/377) were of PCV13 types. Of the 211/377 (56%) isolates tested for drug sensitivity, 23/211 (10.9%), 24/211 (11.4%), 9/211(4.3%) and 148/210 (70.5%) were respectively resistance to oxacillin, chloramphenicol, erythromycin and tetracycline. Thirteen of the oxacillin resistant isolates were additionally multidrug-resistant. No resistance was however detected to gentamycin500µg and to fluoroquinolones (ø Norfloxacin5µg <7mm). Age > 3 months and presence in family of more than one sibling aged < 6 years were significant risk factors for carriage. CONCLUSION: A global rate of 54.5% pneumococcal carriage was detected in this study. The introduced PCV13 vaccine should cover 57.3% (216/377) of circulating serogroups/serotypes, among which were those resistant to antibiotics. Age > 3 months and presence in family of children aged < 6 years were significant factors for pneumococcal carriage. The present data should help understanding post vaccine introduction changes in pneumococcal carriage and infections for better action.

Dual-mode crystal-bound and X-type passivation of quantum dots.

In this report, we present a new path to the control of quantum dot surface chemistry that can lead to a better understanding of nanoscale interfaces and the development of improved photocatalysts. Control of the synthetic methodology leads to QDs that are concomitantly ligated by crystal-bound organics at the surface anion sites and small X-type ligands on the surface cation sites.

Genetic diversity patterns and functional traits of Bradyrhizobium strains associated with Pterocarpus officinalis Jacq. in Caribbean islands and Amazonian forest (French Guiana).

Pterocarpus officinalis Jacq. is a legume tree native to the Caribbean islands and South America growing as a dominant species in swamp forests. To analyze (i) the genetic diversity and (ii) the symbiotic properties of its associated nitrogen-fixing soil bacteria, root nodules were collected from P. officinalis distributed in 16 forest sites of the Caribbean islands and French Guiana. The sequencing of the 16S-23S ribosomal RNA intergenic spacer region (ITS) showed that all bacteria belonged to the Bradyrhizobium genus. Bacteria isolated from insular zones showed very close sequence homologies with Bradyrhizobium genospecies V belonging to the Bradyrhizobium japonicum super-clade. By contrast, bacteria isolated from continental region displayed a larger genetic diversity and belonged to B. elkanii super-clade. Two strains from Puerto Rico and one from French Guiana were not related to any known sequence and could be defined as a new genospecies. Inoculation experiments did not show any host specificity of the Bradyrhizobium strains tested in terms of infectivity. However, homologous Bradyrhizobium sp. strain-P. officinalis provenance associations were more efficient in terms of nodule production, N acquisition, and growth than heterologous ones. The dominant status of P. officinalis in the islands may explain the lower bacterial diversity compared to that found in the continent where P. officinalis is associated with other leguminous tree species. The specificity in efficiency found between Bradyrhizobium strains and host tree provenances could be due to a coevolution process between both partners and needs to be taken in consideration in the framework of rehabilitation plantation programs.

A study of rural Senegalese attitudes and perceptions of their behavior to changes in the climate.

Semi-structured focus group discussions were employed to capture rural Senegalese attitudes and perceptions of their behavior to changes in the climate and their land use and livelihood strategies. Seven focus groups stratified by gender, ethnicity (Wolof and Peulh) and dominant production system (cultivators and pastoralists) in five villages in semi-arid northern Senegal revealed seven main themes. Rural livelihoods remain predominantly based on rainfall dependant practices, and although cultivators and pastoralists had a clear appreciation of changes in natural resources compared to a perceived more favorable past, few adaptive coping strategies beyond established ones were advocated. The seven themes are discussed in detail and their implications for rural livelihoods under future long term climate predictions discussed with the implications of this study for the development of scenarios of future land cover land use.

Response of native soil microbial functions to the controlled mycorrhization of an exotic tree legume, Acacia holosericea in a Sahelian ecosystem.

Fifty years of overexploitation have disturbed most forests within Sahelian areas. Exotic fast growing trees (i.e., Australian Acacia species) have subsequently been introduced for soil improvement and fuelwood production purposes. Additionally, rhizobial or mycorrhizal symbioses have sometimes been favored by means of controlled inoculations to increase the performance of these exotic trees in such arid and semiarid zones. Large-scale anthropogenic introduction of exotic plants could also threaten the native biodiversity and ecosystem resilience. We carried out an experimental reforestation in Burkina Faso in order to study the effects of Acacia holosericea mycorrhizal inoculation on the soil nutrient content, microbial soil functionalities and mycorrhizal soil potential. Treatments consisted of uninoculated A. holosericea, preplanting fertilizer application and arbuscular mycorrhizal inoculation with Glomus intraradices. Our results showed that (i) arbuscular mycorrhizal (AM) inoculation and prefertilizer application significantly improved A. holosericea growth after 4 years of plantation and (ii) the introduction of A. holosericea trees significantly modified soil microbial functions. The results clearly showed that the use of exotic tree legume species should be directly responsible for important changes in soil microbiota with great disturbances in essential functions driven by microbial communities (e.g., catabolic diversity and C cycling, phosphatase activity and P availability). They also highlighted the importance of AM symbiosis in the functioning of soils and forest plantation performances. The AM effect on soil functions was significantly correlated with the enhanced mycorrhizal soil potential recorded in the AM inoculation treatment.

Seasonality of the dietary dimension of household food security in urban Burkina Faso.

Food insecurity is affecting an increasing number of urban poor in the developing world. Yet seasonal characteristics of food intakes have rarely been studied in West African cities. The objective of the present study was to assess the seasonality of the dietary dimension of household food security in Ouagadougou (Burkina Faso). In 2007, two sets of data were collected during the lean and post-harvest seasons, respectively, on a representative sample of 1056 households. At each season, two non-consecutive 24 h recalls were performed at the household level. Food prices were also recorded. Household food security was assessed by the household's mean adequacy ratio (MAR) for energy and eleven micronutrients. Changes in the MAR according to the season were analysed by mixed multivariate linear regression. Results showed that intakes of energy and of ten micronutrients were significantly lower during the lean season than during the post-harvest season, leading to a lower MAR in the lean season (49·61 v. 53·57, P < 0·0001). This was related to less frequent consumption and consumption of smaller amounts of vegetables and of foods prepared at home. Food security relied heavily on food expenses (P < 0·0001) and on the price of meat/fish (P = 0·026). Households with economically dependent adults (P = 0·021) and larger households (P < 0·0001) were the most vulnerable, whereas education (P = 0·030), social network (P = 0·054) and urban origin other than Ouagadougou (P = 0·040) played a positive role in food security. To achieve food security in Ouagadougou, access to micronutrient-dense foods needs to be ensured in all seasons.

Ectomycorrhizal symbiosis of tropical African trees.

The diversity, ecology and function of ectomycorrhizal (EM) fungi and ectomycorrhizas (ECMs) on tropical African tree species are reviewed here. While ECMs are the most frequent mycorrhizal type in temperate and boreal forests, they concern an economically and ecologically important minority of plants in African tropical forests. In these African tropical forests, ECMs are found mainly on caesalpionioid legumes, Sarcolaenaceae, Dipterocarpaceae, Asterpeiaceae, Phyllantaceae, Sapotaceae, Papilionoideae, Gnetaceae and Proteaceae, and distributed in open, gallery and rainforests of the Guineo-Congolian basin, Zambezian Miombo woodlands of East and South-Central Africa and Sudanian savannah woodlands of the sub-sahara. Overall, EM status was confirmed in 93 (26%) among 354 tree species belonging to EM genera. In addition, 195 fungal taxa were identified using morphological descriptions and sequencing of the ML5/ML6 fragment of sporocarps and ECMs from West Africa. Analyses of the belowground EM fungal communities mostly based on fungal internal transcribed spacer sequences of ECMs from Continental Africa, Madagascar and the Seychelles also revealed more than 350 putative species of EM fungi belonging mainly to 18 phylogenetic lineages. As in temperate forests, the /russula-lactarius and /tomentella-thelephora lineages dominated EM fungal flora in tropical Africa. A low level of host preference and dominance of multi-host fungal taxa on different African adult tree species and their seedlings were revealed, suggesting a potential for the formation of common ectomycorrhizal networks. Moreover, the EM inoculum potential in terms of types and density of propagules (spores, sclerotia, EM root fragments and fragments of mycelia strands) in the soil allowed opportunistic root colonisation as well as long-term survival in the soil during the dry season. These are important characteristics when choosing an EM fungus for field application. In this respect, Thelephoroid fungal sp. XM002, an efficient and competitive broad host range EM fungus, possessed these characteristics and appeared to be a good candidate for artificial inoculation of Caesalps and Phyllanthaceae seedlings in nurseries. However, further efforts should be made to assess the genetic and functional diversity of African EM fungi as well as the EM status of unstudied plant species and to strengthen the use of efficient and competitive EM fungi to improve production of ecologically and economically important African multipurpose trees in plantations.

Morphological and molecular analyses in Scleroderma species associated with some Caesalpinioid legumes, Dipterocarpaceae and Phyllanthaceae trees in southern Burkina Faso.

A combination of morphotypes, polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analyses and internal transcribed spacer (ITS) sequencing was used to investigate Scleroderma species that were collected from woodlands in Burkina Faso. We harvested 52 specimens from 20 sites during rainy seasons between 1997 and 2000. According to their morphological features, these specimens were initially characterised, and we then identified six species of Scleroderma. Two of the species were clearly determined as Scleroderma dictyosporum Pat. and S. verrucosum Pers. The four remaining species were characteristically described as (1) displaying big spores with spines up to 2 microm (Scleroderma sp1), (2) producing spores without ornamentation (Scleroderma sp2), (3) spores with very small spines (Scleroderma sp3) and (4) with yellow sporocarps and sub-spherical spores (Scleroderma sp4). The specimens were then analysed using PCR/RFLP of the intergenic regions of rDNA, ITS and IGS1 and ITS sequencing. The restriction fragments obtained with two endonucleases, HinfI and MboI on ITS and IGS1 regions, showed that some isolates of S. dictyosporum had the same patterns as isolates and basidiocarps of Scleroderma sp4 (IR265, IR408, SP4-2903). Isolates of Scleroderma sp3 (IR252) had common restriction fragments as isolates of S. verrucosum (IR500, IR600). Intraspecific differences were observed in the two previously determined species, as well as in Scleroderma sp2. The ITS sequencing and phylogenetic analyses showed that the ribotypes identified by PCR/RFLP within these species might be phylogenetic species. Combining these molecular results allowed regrouping the six morphological species in three sets of cryptic species: a first set with two species including S. dictyosporum Pat., a second set with four species, including both S. verrucosum Pers. and Scleroderma sp1 and a third set with two species, including Scleroderma sp2. These investigations and the combined morphological and molecular analyses used to sort out species paved the way for identifying larger populations of Scleroderma species in Burkina Faso and other tropical zones.