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

First report of naturally infected Sergentomyia minuta with Leishmania major in Tunisia

International audienceBackground: Many sand fly species are implicated in the transmission cycle of Leishmania parasites around the world. Incriminating new sand flies species, as vectors of Leishmania is crucial to understanding the parasite-vector transmission cycle in different areas in Tunisia and surrounding countries. Findings: Seventy-four unfed females belonging to the genera Sergentomyia and Phlebotomus were collected in South Tunisia between June and November 2014, using sticky papers. PCR-RFLP (Restriction Fragment Length Polymorphism) analysis of the internal transcribed spacer 1 (ITS1) was used for Leishmania parasites detection and identification. Leishmania (L.) major (Yakimoff & Shokkor, 1914) was identified within two Sergentomyia (S.) minuta (Rondani, 1843) and one Phlebotomus papatasi (Scopoli, 1786). Conclusion: This is the first report of L. major identified from S. minuta in Tunisia. This novel finding enhances the understanding of the transmission cycle of L. major parasites of cutaneous leishmaniasis in an endemic area in South Tunisia

Study of negative capacitance effect in ferroelectric-paraelectric superlattices

Au fur et à mesure que les composants électroniques se miniaturisent, des limites apparaissent en terme de puissance dissipée et de l’échauffement qui en résulte. Le problème se pose notamment pour les transistors à effet de champ. Le phénomène de capacité négative de ferroélectriques suscite beaucoup d’intérêt car il apparaît comme une solution potentielle pour réduire la consommation de l’énergie des transistors à effet de champ. La stabilisation de ce régime de capacité négative est attendue dans le matériau ferroélectrique lorsqu’il est associé en série à un paraélectrique au sein d’une hétérostructure. Les super-réseaux ferroélectriques / paraélectriques constituent des systèmes modèles pour étudier le phénomène de capacité négative. Notre travail de modélisation utilisant une approche de Kittel révisée, tenant compte à la fois des effets de contraintes et de température, a prédit une capacité négative au sein des super-réseaux Pb(Zr0.2Ti0.8)O3/SrTiO3 et PbTiO3/CaTiO3. Ces deux systèmes ont été étudiés expérimentalement dans le cadre de ce travail. Les super-réseaux ont été élaborés par ablation laser, caractérisés d’un point de vue structural (DRX, MET, AFM) et diélectrique (spectroscopie d’impédance). Dans les super-réseaux Pb(Zr0.2Ti0.8)O3/SrTiO3, nous avons mis en évidence des nanodomaines ferroélectriques à 180°, essentiels à la stabilisation du le phénomène de capacité négative. Les effets électrostatiques ont été confirmés avec la réduction de la température de Curie. L’étude diélectrique en fonction de la température, a mis en évidence la stabilisation de l’effet de capacité négative dans les couches ferroélectriques, en utilisant un modèle de capacités en série. Dans les super-réseaux PbTiO3/CaTiO3, les pertes diélectriques importantes ont empêché l’investigation du régime de capacité négativeElectronic compounds have witnessed the new technology trend of chasing for smaller and smaller devices. However, reducing the sizes has generated a functional limitation like the self-heating of the nonmetric field effect transistors. The ferroelectric negative capacitance phenomenon is gaining a great interest, since it has been proposed as a way to reduce the power consumption of field effect transistors. Negative capacitance effect is expected to be stabilized in a ferroelectric capacitor, when it is connected in series with a paraelectic capacitor. The paraelectric/ferroelectric superlattices provide therefore a model system to investigate the negative capacitance effect. Our modelling work using a modified Kittel approach, which takes into account strain and thermal effects, has predicted a negative capacitance effect in Pb(Zr0.2Ti0.8)O3/SrTiO3 and PbTiO3/CaTiO3 superlattices. For both systems, series of superlattices have been experimentally investigated in this work. Superlattices were grown by pulsed laser desposition, structural characterization (XRD, TEM, AFM) and dielectric investigations were carried out. In Pb(Zr0.2Ti0.8)O3/SrTiO3 superlattices, the presence of 180° stripe polar nanodomains, which are strongly related to the stabilization of negative capacitance, was evidenced. The electrostatic effect was confirmed by a noticeable reduction of the Curie temperature. Temperature-dependent dielectric investigations with impedance spectroscopy have emphasized by using a series capacitor model, a negative capacitance stabilization in the ferroelectric layers. In PbTiO3/CaTiO3 superlattices, high dielectric losses have not allowed to exploit negative capacitance effect

Toxic megacolon complicating a first course of Crohn’s disease: about two cases

Toxic megacolon is a rare and serious complication of Crohn’s disease. Because of the associated high morbidity and mortality, early recognition and management of toxic megacolon is important. Through two cases of toxic megacolon complicating Crohn’s disease, we assessed the clinical, radiologic and therapeutic characteristics of this complication. A 35-year-old man presented a first course of Crohn’s disease treated with corticosteroid. He exhibited sudden severe abdominal pain and distension with shock. A plain abdominal radiography revealed toxic megacolon. He underwent medical therapy, but symptoms not relieved. The patient underwent subtotal colectomy with ileostomy. The resected specimen confirmed the diagnosis. Recovery of digestive continuity was performed. Endoscopic evaluation six months later did not shown recurrence. A 57-year-old man presented with severe acute colitis inaugurating Crohn’s disease, was treated with corticosteroid and antibiotics. He exhibited signs of general peritonitis. Computed tomographic examination revealed toxic megacolon with free perforation, showing prominent dilation of the transverse colon and linear pneumatosis. The patient underwent emergent subtotal colectomy and ileostomy. The final histological patterns were consisting with diagnosis of Crohn’s disease associated with cytomegalovirus infection. The patient underwent antiviral therapy during 15 days. Because of the high risk of postoperative recurrence, he underwent immunosuppressive therapy. Recovery of digestive continuity was performed successfully. Toxic megacolon in Crohn’s disease is a serious turning of this disease. We underscore the importance of early diagnosis of toxic megacolon and rapid surgical intervention if improvement is not observed on medical therapy

Molecular prevalence of Toxoplasma gondii DNA in goats’ milk and seroprevalence in Northwest Tunisia

Toxoplasmosis is a worldwide zoonosis with high impact on human and animal health. Consumption of unpasteurized milk is a risk factor of human toxoplasmosis. The aim of this study was to estimate the seroprevalence and molecular prevalence of T. gondii in goats’ milk in Northwest of Tunisia (Jendouba Governorate). A total number of 77 blood samples were collected from six herds were screened with a commercial ELISA kit for T. gondii antibodies. For the same goats’ samples, a nested PCR was performed to detect T. gondii DNA in milk. The seroprevalence of T. gondii infection was 31.2% (±0.05) while the molecular prevalence of this parasite in milk was estimated to 7.8% (±0.03). A very low value of kappa showed that there is not agreement between seroprevalence and parasite prevalence in milk. These results suggest that the consumption of raw milk from naturally infected goats is a potential source of human infection. An extension programme should be implemented to decrease related to goats’ raw milk consumption

Molecular detection and phylogenetic analyses of Toxoplasma gondii from naturally infected sheep in Northern and Central Tunisia

Toxoplasmosis is a worldwide zoonosis caused by the parasitic protozoan Toxoplasma gondii. It can infect all warm-blooded vertebrate species and causes abortions and birth defects in pregnant women and pregnant ewes. The objective of this study was to estimate the prevalence of infection with T. gondii in sheep meat in the region of Sidi Bouzid (central Tunisia) and Beja (northern Tunisia), the realization of a descriptive study of risk factors and the phylogenetic analyses of T. gondii. Neck muscle samples were obtained from 174 ewes and ewe lamb slaughtered in Sidi Bouzid and 150 lambs slaughtered in Beja. DNA was extracted from the samples using the Wizard® genomic DNA purification kit. A nested PCR using two pairs of primers (NN 1 and NN2, Tg-NP1 and Tg-NP2) were used to detect infection with T. gondii, which was then confirmed by sequencing. Eight T. gondii amplicons were sequenced (accession number KT896498) and deposited in GenBank. The T. gondii amplicons showed 97–100% identities with GenBank sequences. A phylogenetic tree was then constructed. The nested PCR detected T. gondii DNA in 31% of animals tested in Sidi Bouzid and 32% of lambs tested in Beja. No significant difference in the prevalence of T. gondii infection was established between the two tested regions. In both regions, no significant variation of the infection depending on age, breed and locality was found

Static Negative Capacitance Response in Ferroelectric/Paraelectric Superlattices

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Effect of the infection with the nematode <i>Haemonchus contortus</i> (Strongylida: Trichostrongylidae) on the haematological, biochemical, clinical and reproductive traits in rams

This study aimed to investigate the effect of Haemonchus contortus infection on rams’ haematological, biochemical and clinical parameters and reproductive performances. A total number of 12 Barbarine rams (control and infected) were included in the experiment. The infected group received 30 000 H. contortus third-stage larvae orally. Each ram’s ejaculate was immediately evaluated for volume, sperm cell concentration and mortality rate. At the end of the experiment (day 82 post-infection), which lasted 89 days, serial blood samples were collected in order to assess plasma testosterone and luteinising hormone (LH) concentrations. There was an effect of time, infection and their interaction on haematological parameters (p < 0.001). In infected rams, haematocrit, red blood cell count and haemoglobin started to decrease from 21 days post-infection. There was an effect of time and infection for albumin. For total protein, only infection had a statistically significant effect. For glucose, only time had a statistically significant effect. Concentrations were significantly lower in infected rams compared to control animals. A significant effect of infection and time on sperm concentrations and sperm mortality was observed. The effect of infection appears in time for sperm concentrations at days 69 and 76 post-infection. Sperm mortality rate was significantly higher in infected animals at day 46 post-infection when compared to control group (p < 0.05). Finally, plasma testosterone traits (average concentration, cumulated levels during the sampling period and pulse frequency) were depressed in infected rams when compared to control counterparts; none of these endocrine traits were affected for plasma LH

First report of naturally infected Sergentomyia minuta with Leishmania major in Tunisia

Abstract Background Many sand fly species are implicated in the transmission cycle of Leishmania parasites around the world. Incriminating new sand flies species, as vectors of Leishmania is crucial to understanding the parasite–vector transmission cycle in different areas in Tunisia and surrounding countries. Findings Seventy-four unfed females belonging to the genera Sergentomyia and Phlebotomus were collected in South Tunisia between June and November 2014, using sticky papers. PCR-RFLP (Restriction Fragment Length Polymorphism) analysis of the internal transcribed spacer 1 (ITS1) was used for Leishmania parasites detection and identification. Leishmania (L.) major (Yakimoff & Shokkor, 1914) was identified within two Sergentomyia (S.) minuta (Rondani, 1843) and one Phlebotomus papatasi (Scopoli, 1786). Conclusion This is the first report of L. major identified from S. minuta in Tunisia. This novel finding enhances the understanding of the transmission cycle of L. major parasites of cutaneous leishmaniasis in an endemic area in South Tunisia

A preliminary study on microbial air contamination in select schools in Doha, Qatar

Available data of the indoor airborne culturable bacteria and fungi at schools’ environments is very limited in the peninsula of Qatar. This study aims to determine the microbial load in indoor and outdoor air at three schools utilizing two types of air sampling methods: (i) six-stage Andersen cascade impactor for cultivable microbes and (ii) air filtration method for non-cultivable microbes. The maximum levels of airborne culturable bacteria were 971 CFU/m3 in indoor and 334 CFU/m3 in outdoor air samples in the morning in a private (international) school. Lower concentrations of airborne culturable bacteria were recorded in indoor (348 CFU/m3) and outdoor areas (261 CFU/m3) in the afternoon. High CFU numbers (971 CFU/m3) were observed at the food court area during breakfast time, exceeding the WHO indoor air quality limit value. The size distribution of the bacteria had maximum in the 1.1 - 2.3 μm size bin. The most frequently isolated fungal genera were Aspergillus and Penicillium, and their concentration was higher during winter. The prevalence and concentration of airborne microbes were altering spatially (indoors versus outdoors), temporally (morning versus afternoon) and seasonally (winter versus summer). The results indicate that airborne bacterial and fungal spores must be considered as important biological pollutants. Our findings might contribute to the implementation of preventative public health programs and creation of recommendations aimed at providing healthier school environments.We declare that the research reported in this manuscript received supported grant funding from the Qatar National Research Fund (QNRF)-Qatar