Toxoplasma gondii infection and toxoplasmosis in North Africa: a review

Toxoplasmosis is an important zoonosis caused by an obligate intracellular parasitic protozoan, Toxoplasma gondii. The disease is distributed worldwide and can affect all warm-blooded vertebrates, including humans. The present review aimed to collect, compile and summarize the data on the prevalence of T. gondii infection in humans and animals in the five North African countries (Morocco, Algeria, Tunisia, Libya and Egypt). Published data from national and international databases were used. Distribution patterns and risk factors for T. gondii infection are discussed, focusing on biotic and abiotic factors. This review is a comprehensive epidemiological analysis of T. gondii infection in North Africa and will therefore be a useful tool for researchers. It can also be used to propose or enhance appropriate national toxoplasmosis control programs

Spatial and inter-annual variability of proto- and metazooplankton during summer around the Kneiss Islands (Tunisia, Central Mediterranean Sea)

Abstract We studied the distribution of proto- and metazooplankton coupled with environmental factors in the coast area around Kneiss Islands (Central Mediterranean Sea). Zooplanktonic communities were sampled during summer 2009 and summer 2010 at three stations. Our results showed difference in suspended matter concentrations between summer 2009 (92.88 ± 7.15 mg L−1) and summer 2010 (47.37 ± 23.12 mg L−1). Large variations in the N/P ratio were recorded (6.94–36.76) due to the direct influence of the variability in concentration of both the dissolved inorganic nitrogen and dissolved inorganic phosphate components of the ratio. Ciliates abundance peaked in summer 2009 and was 3 times more abundant than summer 2010. Ciliates community composition was dominated by loricate ciliates (75% of total ciliates) in summer 2009 and naked ciliates (56% of total ciliates) in summer 2010. Copepods were the most abundant metazooplankton present during the entire study period, comprising 30–96% of the total metazooplankton community. Small planktonic copepods reached important abundance, particularly oithonids, were found to largely dominate copepods community in both summer 2009 (Oithona nana, 45% of total copepods) and summer 2010 (Oithona similis, 22% of total copepods). The small planktonic species Paracalanus parvus (54% of total copepods) was abundant during summer 2010. The results also indicate that (1) ciliates abundance was very low, showing a possible predation by copepods and also by heterotrophic dinoflagellates, (2) copepods capable to complete a top-down control on phytoplankton and ciliates, with preference to ciliates more than diatoms of similar size and shape and (3) the resistance of loricate ciliates compared to naked ciliates may be explained by their capacity to escape grazing due to the existence of a protective lorica

Restoration impact of an uncontrolled phosphogypsum dump site on the seasonal distribution of abiotic variables, phytoplankton and zooplankton along the near shore of the south-western Mediterranean coast

International audienceIn connection with the Taparura Project, we studied the distribution of phytoplankton and zooplankton communities in relation to environmental variables at 18 stations sampled during four coastal cruises conducted between October 2009 and July 2010 on the north coast of Sfax (Tunisia, western Mediterranean Sea). The inshore location was largely dominated by diatoms (66 %) represented essentially by members of the genera Navicula, Grammatophora, and Licmophora. Dinophyceae were numerically the second largest group and showed an enhanced species richness. Cyanobacteriae developed in association with an important proliferation of colonial Trichodesmium erythraeum, contributing 39.4 % of total phytoplankton abundances. The results suggest that phytoplankters are generally adapted to specific environmental conditions. Copepods were the most abundant zooplankton group (82 %) of total zooplankton. A total of 21 copepod species were identified in all stations, with an overwhelming abundance of Oithona similis in autumn and summer, Euterpina acutifrons in winter, and Oncaea conifera in spring. The phosphogypsum restoration had been acutely necessary allowing dominant zooplankton species to exploit a wide range of food resources including phytoplankton and thus improving water quality

Spatial and seasonal variability of pico-, nano- and microphytoplankton at the bottom seawater in the north coast of Sfax, Eastern Mediterranean Sea

In the frame of the Taparura Project, we studied thedistribution of pico-, nano- and microphytoplankton communitiesin relation to environmental variables at 18 stationssampled during four coastal cruises conducted betweenOctober 2009 and July 2010 at the bottom, on the north coastof Sfax (Tunisia, Eastern Mediterranean Sea). The restorationeffect on coastal ultraphytoplankton (<10 μm) andmicrophytoplankton (<200 μm) was investigated using conventionalflow cytometry and inverted microscopy. Flow cytometryanalysis of ultraphytoplankton resolved six groups(Prochlorococcus, Synechococcus, nanoeukaryotes and threedistinct subgroups within picoeukaryotes). In addition to theseautotrophic groups, two unknown groups were characterisedon the north coast. Picophytoplankton abundance shifted froma summer dominance of Synechococcus to a dominance ofpicoeukaryotes and Prochlorococcus during spring.Nanoeukaryotes were the most abundant in spring.Microphytoplankton was resolved into five groups, labelledBacillariophyceae, Dinophyceae, Cyanobacteriae,Euglenophyceae and Chlorophyceae. A total of 90microphytoplankton species were identified in all stations,with an overwhelming abundance of large diatoms, a typicaltrait of benthic communities (Coscinodiscus sp.,Grammatophora sp., Navicula sp., Pleurosigma sp.,Striatella unipunctata …). Results collected in this study arefavouring a beneficial impact on the ecosystem of the Sfaxnorth coast restoration achieved by the Taparura Project

Spring plankton community structure and distribution in the north and south coasts of Sfax (Tunisia) after north coast restoration

International audienceThe first phase of the Taparura Project aimed at restoring the north coast of Sfax (Tunisia), highly polluted by phosphate industry and uncontrolled phosphogypsum dumping. Before restoration of the north coast of Sfax, we investigated the state of the ecosystem in related coastal waters. To establish the impact of the Taparura Project, we conducted a similar study both after restoration. To discriminate natural changes over time, we extended the study to the south coast of Sfax, submitted to the same industrial pressure but not yet restored. The present study, conducted in May 2010 at 36 stations (18 on each coast, north and south), covered the spatial distribution of the microbial assemblage, nutrients, and abiotic parameters by collecting seawater samples at the surface and the water–sediment interface. Results revealed a striking difference between the two coasts regarding pH, with strong acidification of seawater in the south, likely generated by industrial activity. Suspended matter was higher in the north than in the south. Flow cytometry analysis of ultraphytoplankton (<10 μm) resolved six groups (Prochlorococcus, Synechococcus, nanoeukaryotes and three distinct subgroups within picoeukaryotes). In addition to these autotrophic groups, two unknown groups were characterised on the south coast. Heterotrophic prokaryotes were resolved into three groups, labelled LNA (low nucleic acid content), HNA1 and HNA2 (high nucleic acid content). Prochloroccocus, pico-nano-microphytoplankton, heterotrophic prokaryotes and ciliates were more abundant in the north, whereas Synechococcus and unknown species were more abundant in the south where chl a concentration was also higher. The results show that restoration had positive effects on the microbial assemblage of the north coast; they also highlight the strong acidification still prevalent in the south that may be responsible for the lower development of most phytoplankton groups and the occurrence of unknown species. The case for restoration of the city’s south coast is also reinforced

Seasonal distribution of ultraphytoplankton and heterotrophic prokaryotes in relation to abiotic variables on the north coast of Sfax after restoration

The Taparura project was set up to restore the north Sfax coast (Tunisia) by shutting down the northernphosphate plant responsible for chronic pollution and uncontrolled phosphogypsum dumping. The restorationeffect on coastal ultraphytoplankton (<10 lm) and heterotrophic prokaryotes was investigatedusing conventional flow cytometry over four successive seasons during 2009–2010. Cell concentrationswere generally higher than values reported for the open sea, both in the western and eastern Mediterraneanbasins. One striking point was that chl a concentration on the north Sfax coast was unchanged afterrestoration but was still one order of magnitude higher than in the Gulf of Gabès. Restoration of pH, followingthe shutdown of the phosphate processing plants on the north coast, appeared to reach normallevels for seawater during the study, whereas seawater acidification persisted on the south coast whereplants are still in operation. The largest ultraphytoplankton biomass was from an unknown cell group,whose identity and role needs to be established

Impacts of an uncontrolled phosphogypsum dumpsite on summer distribution of phytoplankton, copepods and ciliates in relation to abiotic variables along the near-shore of the southwestern

International audienceIn connection with the Taparura Project, studies of spatial distribution of the crustacean zooplankton community, nutrients, phytoplankton and ciliates were conducted in July 2007 at 45 stations spread over fifteen transects along the coast north of Sfax. The results showed that the N/P ratio was lower than the Redfield ratio, suggesting potential N limitation. Phytoplankton was characterised by the proliferation of several diatoms, while ciliates were largely dominated by spirotrichs. Copepods were the most abundant zooplankton present during the entire study period, comprising 61% of the total zooplankton community. Twelve copepod families were identified at every station, with a high percentage of Oithonidae (77% of copepods) dominated by Oithona nana. The abundance of this species was correlated with that of diatoms, Cocoolithophorideae and ciliated Colpodea, suggesting that O. nana may feed on a wide range of prey. Despite human pressure and industrial activities, the coastal waters north of Sfax showed a wide diversity of phytoplankton, ciliates and zooplankton

Spatial variation of summer microphytoplankton and zooplankton communities related to environmental parameters in the coastal area of Djerba Island (Tunisia, Eastern Mediterranean)

International audienceIn the present study, we investigated the effects of pollution and anthropization on the summer distribution of phyto-zooplanktoncommunities in relation to environmental factors in the coastal zone of DjerbaIsland. On the basis of chemical factors, theDjerba coasts can be divided into two parts: the Western Area (WA), characterized by high values of nitrogen forms of nutrients,with higher N/P ratio, and the Eastern Area (EA), poorer in inorganic nitrogen with an N/P ratio lower than the Redfield ratio (16).Strong differences in terms of plankton communities were also observed between these two areas. Bacillariophyceae was the most important microphytoplankton group in the WA whereas the proportion of Cyanobacteria was higher in the EA. High Cyanobacteria abundance in the EA may be linked to high DIP concentration. In the WA, the Bacillariophyceae Chaetoceros, Coscinodiscus, Grammatophora, Navicula and Pinnularia reached high abundance in relation with their good adaptability to adverse conditions. Copepods were the most abundant zooplankton present in the WA (54–100% of total zooplankton abundance), whereas other zooplankton were always dominant (60–90%) in the EA. The small pollution-tolerant Calanoid copepod Paracalanus parvus was dominant in the WA, illustrating its affinity for highly eutrophic sites. Despite human pressure and industrial activities, the coastal waters of Djerba showed a wide diversity of microphytoplankton and zooplankton