The history of leishmaniasis

In this review article the history of leishmaniasis is discussed regarding the origin of the genus Leishmania in the Mesozoic era and its subsequent geographical distribution, initial evidence of the disease in ancient times, first accounts of the infection in the Middle Ages, and the discovery of Leishmania parasites as causative agents of leishmaniasis in modern times. With respect to the origin and dispersal of Leishmania parasites, the three currently debated hypotheses (Palaearctic, Neotropical and supercontinental origin, respectively) are presented. Ancient documents and paleoparasitological data indicate that leishmaniasis was already widespread in antiquity. Identification of Leishmania parasites as etiological agents and sand flies as the transmission vectors of leishmaniasis started at the beginning of the 20th century and the discovery of new Leishmania and sand fly species continued well into the 21st century. Lately, the Syrian civil war and refugee crises have shown that leishmaniasis epidemics can happen any time in conflict areas and neighbouring regions where the disease was previously endemic

Development of a Halotolerant Community in the St. Lucia Estuary (South Africa) during a Hypersaline Phase

Background: The St. Lucia Estuary, Africa’s largest estuarine lake, is currently experiencing unprecedented freshwater deprivation which has resulted in a northward gradient of drought effects, with hypersaline conditions in its northern lakes. Methodology/Principal Findings: This study documents the changes that occurred in the biotic communities at False Bay from May 2010 to June 2011, in order to better understand ecosystem functioning in hypersaline habitats. Few zooplankton taxa were able to withstand the harsh environmental conditions during 2010. These were the flatworm Macrostomum sp., the harpacticoid copepod Cletocamptus confluens, the cyclopoid copepod Apocyclops cf. dengizicus and the ciliate Fabrea cf. salina. In addition to their exceptional salinity tolerance, they were involved in a remarkably simple food web. In June 2009, a bloom of an orange-pigmented cyanobacterium (Cyanothece sp.) was recorded in False Bay and persisted uninterruptedly for 18 months. Stable isotope analysis suggests that this cyanobacterium was the main prey item of F. cf. salina. This ciliate was then consumed by A. cf. dengizicus, which in turn was presumably consumed by flamingos as they flocked in the area when the copepods attained swarming densities. On the shore, cyanobacteria mats contributed to a population explosion of the staphylinid beetle Bledius pilicollis. Although zooplankton disappeared once salinities exceeded 130, many taxa are capable of producing spores or resting cysts to bridge harsh periods. The hypersaline community was disrupted by heavy summer rains in 2011, which alleviated drought conditions and resulted in a sharp increase in zooplankton stock an

Impact of forest harvesting on water quality and fluorescence characteristics of dissolved organic matter in eastern Canadian Boreal Shield lakes in summer

Forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. Water quality and fluorescence characteristics of dissolved organic matter (DOM) were measured over a 3-year period in eight eastern Boreal Shield lakes: four lakes were studied before, 1 and 2 years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. ANOVAs showed a significant increase in total phosphorus (TP) in perturbed lakes when the three sampling dates were considered and in DOC concentrations when considering 1 year before and 1 year after the perturbation only. At 1 year post-clear cutting DOC concentrations were about 15 % greater in the perturbed lakes at ~ 15 mgC L⁻¹ compared to 12.5 mgC L⁻¹ in the unperturbed lakes. In contrast, absorbance and fluorescence measurements showed that all metrics remained within narrow ranges compared to the range observed in natural waters, indicating that forest harvesting did not affect the nature of DOM characterized with spectroscopic techniques. These results confirm an impact of forestry activities 1 year after the perturbation. However, this effect seems to be mitigated 2 years after, indicating that the system shows high resilience and may be able to return to its original condition in terms of water quality parameters assessed in this study

Recruitment in the light of biological- physical interactions in coastal waters: Reuslts of PNDR action at the Arago Laboratory in 1994- 1995

21 páginas, 10 figuras[EN]This paper presents the work of the Arago Laboratory larval biology team developed close to the Laboratory but also in other areas which differ either by the dominant pattern of life cycle (subantarctic area) or by the conditions of water mass transport (Arcachon area on the Atlantic coast). The ultimate objective is the identification of the factors giving rise to the variability of populations. In this context, physical processes seem of primary interest for two reasons: a) they create a structure within which biological processes may proceed, and b) they influence the rate of these biological processes. Their identification and quantification form a fundamental point in our project In Mediterranean populations of the target species Eupolymnia nebulosa, the mucilaginous egg mass sheltering larvae is related to the control of larval dissemination. Broadly speaking, development with reduction or suppression of the pelagic life, is considered as a response to the negative effects of dissemination. In this conceptual frame, life cycle evolution must have gone from benthoplanktonic to holobenthic development. The former is considered plesiomorphic, the latter is expressed by a very wide range of solutions. A rough scheme of the seasonal variability of recruitment based on larval releasing has been elaborated: spring rise of temperature is of prime importance in the success of recruitment. The study of year to year variations in recruitment shows that short term perturbations may be at the root of the variable success of the species. The biomass level of E. nebulosa is determined during short periods of the year such as the prolongation or shortening of the thermocline, and the temporary fall of temperature breaking the smooth profile of the spring rising temperature curve. Consequently, in order to explain variation of recruitment, it is necessary to disregard the annual or monthly means which may suppress or seriously obscure short term deviations. Larvae-substrate relationships are complex. Larvae settle on heterogeneous substratum. A solid basis or fulcrum is a requisite for coordination of movements which make possible manipulation of particles used for tube building and for feeding. This double constraint relative to the nature of substratum reflects living conditions of adults and not feeding processes. When considered as a whole, the main function of a life cycle is to secure the return of larvae to the adult habitat. This is achieved by several strategies among which the control of dissemination and the development of an elaborate larval behaviour can be pointed out.[FR]Ce travail presente les activites de I'equipe de biologie larvaire du laboratoire Arago. Ces activites sont developpees a proximite de ce laboratoire, sur la cote fran<;:aise catalane, mais aussi dans d' autres zones qui different par Ie type dominant du developpement (province subantarctique) ou par les conditions de transport des masses d'eau (Bassin d' Arcachon sur la cote Atlantique). Le but essentiel est I' identification des facteurs aI' origine de la variabilite, ce qui suppose la connaissance precise des differentes etapes du developpement. Dans ce contexte, les processus physiques apparaissent primordiaux pour deux raisons: a) ils creent des structures a I'interieur desquelles les processus biologiques se developpent et b) ils influencent la vitesse de ces memes processus. Leur identification et leur quantification constituent un point fondamental de notre programme. Chez les populations mediterraneennes de I'espece cible Eupolymnia nebulosa, la structure mucilagineuse abritant les larves controle la dissemination de ces Im'ves. De fa<;:on plus generale Ie developpement avec reduction de la duree de la phase pelagique est considere comme une reponse aux effets negatifs de la dissemination; dans ce schema conceptuel, I' evolution des cycles de vie part du developpement benthoplanctonique representant un caractere plesiomorphe en direction du development holobenthique qui se manifeste par des solutions tres diversifiees. Un schema, encore simple de la variabilite saisonniere du succes du recrutement, a ete elabore apartir des modalites de liberation des larves au cours de la saison de reproduction. Ces modalites dependent fortement des variations de la temperature ambiante. L' etude des variations interannuelles du recrutement montre que des perturbations a court terme de la temperature, peuvent etre a l' origine du succes variable d'une espece. Ainsi Ie niveau de biomasse de E. nebulosa est determine durant de courtes fractions du cycle de variation de la temperature: lors d'une prolongation ou d'un raccourcissement de la periode de thermocline ou lors de la chute provisoire de la temperature au cours de l'augmentation de la temperature printaniere. En consequence, il apparait necessaire, pour expliquer les variations du recrutement, de negliger les moyennes annuelles ou mensuelles qui suppriment ou gomment serieusement les deviations a court terme. L'etude des relations de la larve et du substrat met en evidence la necessite d'un substrat heterogene au moment de la fixation; une base stable est necessaire pour la coordination des mouvements; cette coordination rend possible la manipulation des particules les plus fines du substrat, utilisees pour la construction du tube et la nourriture. Cette double contrainte reflete I'habitat de I'adulte et non les procedes de nutrition. Considere globalement, Ie cycle de vie a comme fonction fondamentale d'assurer Ie retour des larves dans I'habitat des adultes, ce qui est realise par differentes strategies parmi lesquelles Ie controle de la dissemination et Ie developpement d'un comportement larvaire elabore.This work is a contribution to the French National Program on Determinants of Recruitment (PNDR France-GLOBEC) and was financed by grants 1) from Ministerio de Educacion y Cienca of Spain and Consejo Superior de Investigaciones Cientificas of Spain, 2) from French IFREMER and CNRS to several co-authors.Peer reviewe