Search

The severity of toxoplasmic infection depends mainly on the immune status of the host, but also on the Toxoplasma gondii strains, which differ by their virulence profile. The relationship between the human host and T. gondii has not yet been elucidated because few studies have been conducted on human models. The immune mechanisms involved in the persistence of T. gondii in the brains of immunocompetent subjects and during the reactivation of latent infections are still unclear. In this study, we analyzed the kinetics of immune mediators in human nervous cells in vitro, infected with two strains of T. gondii. Human neuroblast cell line (SH SY5Y), microglial (CMH5) and endothelial cells (Hbmec) were infected separately by RH (type I) or PRU (type II) strains for 8 h, 14 h, 24 h and 48 h (ratio 1 cell: 2 tachyzoites). Pro-inflammatory protein expression was different between the two strains and among different human nervous cells. The cytokines IL-6, IL-8 and the chemokines MCP-1 and GROα, and SERPIN E1 were significantly increased in CMH5 and SH SY5Y at 24 h pi. At this point of infection, the parasite burden declined in microglial cells and neurons, but remained high in endothelial cells. This differential effect on the early parasite multiplication may be correlated with a higher production of immune mediators by neurons and microglial cells compared to endothelial cells. Regarding strain differences, PRU strain, but not RH strain, stimulates all cells to produce pro-inflammatory growth factors, G-CSF and GM-CSF. These proteins could increase the inflammatory effect of this type II strain. These results suggest that the different protein expression profiles depend on the parasitic strain and on the human nervous cell type, and that this could be at the origin of diverse brain lesions caused by T. gondii.

Classically, Toxoplasma infection is associated with high levels of specific IgM antibody and a rise in specific IgG levels 1 to 3 weeks later. Atypical IgG seroconversion, without IgM detection or with transient IgM levels, has been described during serologic follow-up of seronegative pregnant women and raises difficulties in interpreting the results. To evaluate the frequency and the characteristics of these atypical cases of seroconversion, an investigation was conducted within the French National Reference Center for Toxoplasmosis, from which 26 cases collected from 12 laboratories belonging to the network were identified. The aim of this work was to retrospectively analyze the results of serologic testing, the treatments administered, and the results of prenatal and postnatal follow-up for these women. In each case, IgG antibodies were detected using both screening and confirmatory tests. IgM antibodies were not detected in 15 cases, and the levels were equivocal or low-positive in 11 cases. The IgG avidity results were low in 16 cases and high in one case. Most of the pregnant women (22/26) were treated with spiramycin from the time that IgG antibodies appeared until delivery. Amniotic fluid was analyzed for Toxoplasma gondii DNA by PCR in 11/26 cases, and the results were negative in all cases. Congenital toxoplasmosis was ruled out in 12/26 newborns. There was no abnormality observed at birth for 10 newborns and no information available for 4 newborns. In conclusion, when the interpretation of serological results is so difficult, it seems cautious to initiate treatment by spiramycin and to follow the pregnant women and their newborns.

Background: Chloroquine (CQ) was the main malaria therapy worldwide from the 1940s until the 1990s. Following the emergence of CQ-resistant Plasmodium falciparum, most African countries discontinued the use of CQ, and now promote artemisinin-based combination therapy as the first-line treatment. This change was generally initiated during the last decade in West and Central Africa. The aim of this study is to describe the changes in CQ susceptibility in this African region, using travellers returning from this region as a sentinel system., Methods: The study was conducted by the Malaria National Reference Centre, France. The database collated the pfcrtK76T molecular marker for CQ susceptibility and the in vitro response to CQ of parasites from travellers' isolates returning from Senegal, Mali, Ivory Coast or Cameroon. As a proxy of drug pressure, data regarding CQ intake in febrile children were collated for the study period. Logistic regression models were used to detect trends in the proportions of CQ resistant isolates., Results: A total of 2874 parasite isolates were genotyped between 2000-2011. The prevalence of the pfcrt76T mutant genotype significantly decreased for Senegal (from 78% to 47%), Ivory Coast (from 63% to 37%), Cameroon (from 90% to 59%) and remained stable for Mali. The geometric mean of the 50% inhibitory concentration (IC50) of CQ in vitro susceptibility and the proportion of resistant isolates (defining resistance as an IC50 value > 100 nM) significantly decreased for Senegal (from 86 nM (59%) to 39 nM (25%)), Mali (from 84 nM (50%) to 51 nM (31%)), Ivory Coast (from 75 nM (59%) to 29 nM (16%)) and Cameroon (from 181 nM (75%) to 51 nM (37%)). Both analyses (molecular and in vitro susceptibility) were performed for the 2004-2011 period, after the four countries had officially discontinued CQ and showed an accelerated decline of the resistant isolates for the four countries. Meanwhile, CQ use among children significantly deceased in this region (fixed effects slope = -0.3, p < 10-3)., Conclusions: An increase in CQ susceptibility following official withdrawal of the drug was observed in travellers returning from West and Central African countries. The same trends were observed for molecular and in vitro analysis between 2004-2011 and they correlated to the decrease of the drug pressure.

Atypical Toxoplasma gondii strains, unrelated to archetypal clonal lineages (I, II, III), have been reported more frequently over the last decade in areas other than Europe and North America. A newly described form of toxoplasmosis, 'Amazonian toxoplasmosis' (AT), has been reported since 2002 in French Guiana. It is characterized by severe cases and atypical strains linked to a neotropical forest-based cycle. We report on the cases of AT that required intensive care management. We performed a prospective observational study on hospitalized adults in the Intensive Care Unit (ICU) from 2002 to 2008. Clinical and laboratory data, microbiological findings and outcomes were recorded. Data, including the ICU simplified acute physiology score and the pneumonia severity index, were calculated. Epidemiological risk factors for AT were assessed through questionnaires. Eleven non-immunodeficient patients were admitted to the ICU in Cayenne for life-threatening pneumonia associated with disseminated toxoplasmosis. Mechanical ventilation was necessary in seven patients, four of whom required immediate orotracheal intubation. Cardiac and ophthalmological abnormalities were found in five and four patients, respectively. One patient died from multiple organ failure. The genetic characterization of Toxoplasma DNA using six microsatellite markers revealed unique and atypical genotypes in eight patients. All patients presented epidemiological risk factors for AT. In French Guiana, significant T. gondii-related infectious syndrome associated with the lungs, a high level of LDH activity and the reported risk factors for AT was strongly suggestive of disseminated toxoplasmosis with a possible trend toward life-threatening pneumonia., (© 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.)

Chronic necrotizing or semi-invasive aspergillosis represents a disease commonly occurred in patients with mild immunodeficiency. We report a case of chronic necrotizing pulmonary aspergillosis in immunocompetent patient without underlying disease. The discovery of the disease was made accidentally, by finding a nodular opacity on a routine chest X-ray. The diagnostic was confirmed by pathological and bacteriological examination. With specific antifungal treatment, no complete eradication was obtained and the patient has a slow evolution with many relapses.

Toxoplasma gondii is a highly prevalent protozoan parasite that infects a wide range of animals and threatens human health by contaminating food and water. A markedly limited number of clonal parasite lineages have been recognized as predominating in North American and European populations, whereas strains from South America are comparatively diverse. Here, we show that strains from North America and Europe share distinct genetic polymorphisms that are mutually exclusive from polymorphisms in strains from the south. A striking exception to this geographic segregation is a monomorphic version of one chromosome (Chr1a) that characterizes virtually all northern and many southern isolates. Using a combination of molecular phylogenetic and phenotypic analyses, we conclude that northern and southern parasite populations diverged from a common ancestor in isolation over a period of approximately 10(6) yr, and that the monomorphic Chr1a has swept each population within the past 10,000 years. Like its definitive feline hosts, T. gondii may have entered South America and diversified there after reestablishment of the Panamanian land bridge. Since then, recombination has been an infrequent but important force in generating new T. gondii genotypes. Genes unique to a monomorphic version of a single parasite chromosome may have facilitated a recent population sweep of a limited number of highly successful T. gondii lineages.

The utility of sequence polymorphisms in the dense granule antigen GRA6 gene as typing markers for Toxoplasma gondii was investigated. The coding region of GRA6 was amplified, sequenced and compared for 30 Toxoplasma strains from eight different zymodemes (Z1-Z8). Sequence alignment identified nucleotide polymorphisms at 24 positions out of 690 bp, which correlated with murine-virulence. Types I, II, and III could be distinguished from each other on the basis of three, 10, and six variable positions, respectively. Two deletions of 15 bp and 3 bp existed in the avirulent (type II) strains. With one exception, all polymorphic positions resulted in amino acid substitutions, and the two gaps of 15 bp and 3 bp caused the deletion of six amino acids in type II strains. Intra-specific polymorphisms were also found in the virulent group. A high degree of sequence polymorphism correlating with the phenotypes of T. gondii strains points to the GRA6 gene being a good marker for strain characterisation and typing of the isolates of this apicomplexan. The large variety of amino acid changes supports the view that the GRA6 protein plays an important role in the antigenicity and pathogenicity of T. gondii. The existence of polymorphic restriction sites for endonuclease MseI was used to develop a PCR-RFLP method which could simply differentiate the three different groups (types I, II, III) of T. gondii.

Background: We report the first case of a double maternal seroconversion for Toxoplasma gondii (TG) and cytomegalovirus (CMV) diagnosed during pregnancy., Case: One case is reported of a female patient referred for seroconversion in response to TG in the 27th week of gestation. A search for foetal involvement revealed signs of non-specific foetal infection without any TG-related lesions. Tests were carried out for another foeto-maternal infectious disease and maternal seroconversion in response to CMV was discovered with virus in the amniotic fluid. The foetus developed hydrocephalus and intracranial calcifications and the pregnancy was terminated at the parents' request. CMV-induced multiple organ involvement without any signs of Toxoplasma gondii-related involvement were noted in the foetus., Conclusions: This case indicates that a search should be made for another infectious disease likely to involve the foetus when non-specific signs of infection in the foetus are present, even though maternal seroconversion has been recognized.

Hammondia hammondi is an obligate heteroxenous intestinal coccidian of cats, sharing many characteristics with Toxoplasma gondii. The tachyzoite stage antigens of T. gondii and H. hammondi were studied by immunofluorescence assays (IFA) and western blotting (WB) techniques to demonstrate antigenic similarities. Five monoclonal antibodies (MAbs), anti-T. gondii antigens, P22, P23, P30, P35, and P43, and mice polyclonal anti-H. hammondi serum were investigated. Antigens of H. hammondi were recognized by anti-P30 MAb both in IFA and in WB and by anti-P22 and anti-P35 MAbs only in IFA. Polyclonal anti-H. hammondi serum revealed many common antigens between the 2 parasites (30, 32, 35, 66, and 90 kDa). The differences of host parasite relationship between these 2 coccidians lead us to suggest that many of these antigens with similar molecular weights are not the same, but homologous, molecules or that they are not the only factors involved in these differences.

Since we have previously demonstrated the protective role against infection played by Toxoplasma excreted-secreted antigens (Darcy et al. Parasite Immunology, 10, 553-567, 1988), the aim of the present work was an attempt to precisely define the location of GRA1, GRA2, and GRA5 in both the tachyzoite and the bradyzoite stages from distinct strains, in order to explore the mechanisms of secretion by Toxoplasma gondii. Three monoclonal antibodies (Charif et al. 1990) and colloidal immunogold labeling were used to localize the 27-, 28.5-, and 21-kDa target antigens to the matrix of the dense granules of tachyzoites and bradyzoites. They were, moreover, detected in the parasitophorous vacuole and in the cyst ground substance after host cell invasion. Our data suggest that a selective sorting mechanism for dense-granule contents exists at least in encysted bradyzoites. GRA2 was found preferentially associated with the ground substance of the cyst wall and the tubular elements of the network of the modified host cell phagosome, whereas GRA5 was located on the delimiting membrane of both the cyst wall and the parasitophorous vacuole. These observations reveal the selective targeting of dense-granule molecules, which could have different functions and fates when exocytosed into the parasite-containing vacuole.

Macrophages collected from BCG-infected mice or exposed in vitro to interferon-gamma plus lipopolysaccharide developed a cytostatic activity on Trypanosoma brucei gambiense and Trypanosoma brucei brucei. This trypanostatic activity of activated macrophages was inhibited by addition of N-monomethyl-L-arginine, an inhibitor of the L-arginine-nitric oxide (NO) metabolic pathway, indicating a role for NO as the effector molecule. Contrary to trypanosomes treated with N2gas, trypanosomes treated with NO gas did not proliferate in vitro on normal macrophages. Compared to mice infected with control parasites, mice infected with NO-treated parasites had decreased parasitemias in the first days postinfection and had a prolonged survival. Addition of excess iron reversed the trypanostatic effect of both activated macrophages and NO gas. These data show that activated macrophages exert an antimicrobial effect on T.b. gambiense and T.b. brucei through the L-arginine-NO metabolic pathway. In trypanosomes, NO could trigger iron loss from critical targets involved in parasite division. The participation of this effector mechanism among the other immune elements involved in the control of African trypanosomes (antibodies, complement, phagocytic events) remains to be defined.

Sheep were used as an experimental model to study trypanosomiasis. Twelve animals were infected with Trypanosoma brucei brucei, and the clinical evolution of the disease in the sheep corresponded closely to that described in human patients. The main clinical signs of the experimental infection were hyperthermia, anaemia, loss of weight and behavioural disturbances. Death occurred in all cases after a mean time of 75 days. Trypanosomes were detected in blood films nine to 15 days after inoculation, and the parasitaemia was usually mild and irregular. Changes in the cerebrospinal fluid--increase in leucocyte counts and the presence of trypanosomes--appeared after about 45 days. This model would provide a valuable way of testing the effectiveness of new therapeutic drugs.

An experimental model of human african trypanosomiasis is realized in sheep with Trypanosoma brucei brucei. Clinical and biological evolution is comparable to human disease. This model is useful to test efficient drugs and to get a better knowledge about sleeping sickness physiopathology.

An experiment was carried out on treatment of Trypanosoma brucei brucei experimentally infected sheep with central nervous system involvement with a 2-nitroimidazole derivative: Ro 15-0216 (Hoffmann La Roche & Co Ltd, Basel, Switzerland). After a single intramuscularly or intravenously administration (25 or 50 mg/kg) of this compound in healthy sheep, levels of more than 1 microgram/ml corresponding to trypanocidal concentrations are detected in both blood and cerebrospinal fluid. However, because of short half life, two or three injections a day appeared to be necessary. Six infected sheep were treated by daily intravenous injection for six days: three animals with 25 mg/kg/d and three others with 50 mg/kg/d. Animals which relapsed received 50 mg/kg/d divided in three intravenous injections a day for six days. After a year of observation, all the animals were considered clinically and biologically cured.

Sheep that have been experimentally infected with a strain of Trypanosoma brucei brucei reproduce the clinical symptomatology of human African trypanosomiasis. We measured two biochemical parameters which are altered during the infection; total serum and cerebrospinal fluid (CSF) proteins, and the time of appearance and levels of IgM in both serum and CSF. Serum protein levels were considerably raised (up to 90 gl-1), although in CSF the levels were always less than 1 gl-1. The ratio of serum albumin to globulins fell to a value of 0.40 during the course of the disease. Electrophoresis of CSF proteins demonstrated the appearance of polyclonal immunoglobulins. Plasma IgM levels rose to ten times normal values, and after the sixth week IgMs made up 10% of total CSF protein content. Specific antibodies were detected, by both indirect immunofluorescence and an ELISA technique, within two weeks after infection in the blood and after four weeks in the CSF.

2,166 cases of joint infection in adults were reviewed during a national inquiry. The peripheral infections due to common germs (1,080 cases) and tubercle bacilli (260 cases) were characterised by their frequency after the age of 60, the role of corticotherapy in onset of the infection and the predominance of staphylococci (60%) in pyogenic infections, the low proportion of deaths (4%) and the necessity of early treatment to observe better functional results. The vertebral lesions due to common bacteria (491 cases) were mainly localised in the lumbar regions (70%) whereas tuberculous infections (335 cases) usually affect the lower dorsal vertebrae (50%). Neurological signs and abscess were more frequent during tuberculous involvement. Needle puncture of the vertebral focus should be recommended owing to its help in etiological diagnosis. A cure was generally obtained without operation in the form of complete or incomplete block, this appearance is, however, less frequent than radiological signs of fixed osteolysis. The mortality is just as low as in peripheral infections.

Trypanosoma brucei brucei experimentally infected sheep with central nervous system involvement were treated with melarsoprol (Arsobal, Specia, France). The purpose was to determine minimum efficiency concentrations of this drug. Eight sheep divided in four groups of two animals were treated intravenously for 3 days with the following respective dosages: 1.8, 0.9, 0.45 and 0.225 mg/kg/d. After a year of observation, efficient dosages were 1.8 and 0.9 mg/kg/d. The experimentation suggests the possibility to reduce usually given dosages in man.

Broad variations in complement levels are seen during the course of many infectious diseases, particularly human and animal african trypanosomiasis. In this study, sheep complement is measured by means of its haemolytic activity expressed in 50% haemolytic complement units per ml (HCU50/ml). In healthy sheep, the average value is 23.3 HCU50/ml. Complement levels dramatically decrease five days after subcutaneous inoculation of Trypanosoma brucei brucei and remain undetectable until death of non treated infected animals. Eight infected sheep are treated with graded dosages of melarsoprol when central nervous system involvement appeared. Complement levels rapidly recover normal values after efficient treatment (0.9 and 1.8 mg/kg/d).

An experimental study was carried out using 5 Trypanosoma brucei brucei subcutaneously infected sheep. Pentamidine treatment appeared in the CSF. Two animals were injected daily for 10 days and they died with drug intoxication. Two animals received drug every 3 days for 15 days: one of them died, the other was cured after 3 weeks of set-back. This preliminary study should be completed by experimentation made over a more important period of time.

Atacora Province has been for a long time a focus of human trypanosomiasis in the People's Republic of Benin. If the prevalence has appreciably decreased in the 1960s on account of the experienced methods of tracking down and a sustained supervision, it is easy to establish and to fear today the waking and even the extension of the historic focus formerly called "Foyer Atacora". Since 1974, new patients in second period of the infection are tracked down each year; they particularly come from the localities of Tanguieta and Materi. This suggests that sleeping sickness still persists in the North Country; that is the reason why it appears interesting to evaluate the present state of African human trypanosomiasis in this region of Benin; this appraisal has been tried from a clinic and serologic survey during May 1986 in the the population of four localities of this province: N'Dahonta, Porga Forêt, Porga Village and Dassari.

In april 1987, an epidemiologic study in Northern Togo was carried out in order to evaluate the prevalence of cysticercosis and epilepsy. The survey also aimed to investigate possible connections between these two illnesses. The study encompassed 5264 subjects over 15 years old, selected using random sampling techniques; 125 cases of cysticercosis were diagnosed (2.4% of sample population); 12 by anatomo-pathological examination of cysts 18 (14.4%) based on skull and muscle x-ray calcifications and 104 patients were identified using ELISA tests on 1527 serum samples (optical density greater than or equal to 0.4). Among 88 epileptic patients (prevalence = 16.7 per thousand), 27 also suffered from cysticercosis (38.7% of all epileptic patients, 21.6% of cysticercosis patients and 0.51% of the total population).

This study reports the action of ten drugs on two strains of Trypanosoma brucei brucei (Antat 1.9 virulent in mice and Antat 1.1E more chronic) in vitro in acellular semi defined medium and in vivo in Swiss mice. Minimum efficient concentration of drugs is evaluated by means of an in vitro assay: melarsoprol (1 microgram/ml); DFMO (cytostatic effect from 50 micrograms/ml); suramin (1 microgram/ml); 2 nitroimidazole derivative Ro 15-0216 (1 microgram/ml); triacetylbenzene trisguanylhydrazone (TBG) (between 1 and 10 mg/ml). Fluconazole is not efficient in vitro on T. b. brucei. In vivo: TBG is efficient at 3 mg/kg, DFMO given orally and intraperitoneally is not efficient at 4 g/kg, but surviving time of mice is increased. Suramin (20 mg/kg/d X 4) alone or associated with ornidazole (50 and 500 mg/kg/d X 4) is efficient on bloodstream trypanosomes but no efficacy is revealed on brain forms. Cyclosporin (30 mg/kg/d X 3) lightly increases surviving time of mice. Fluconazole, pefloxacin and acyclovir are not efficient in vivo.

Total lipid extracts from Trypanosoma brucei brucei (T.b.b.), Trypanosoma brucei gambiense (T.b.g.) and Trypanosoma brucei rhodesiense (T.b.r.) were hydrolyzed and the liberated fatty acids were methylated before analysis by gas-liquid chromatography on capillary columns. The sums of the percentages for fatty acids from the different series were compared and the following relationships for the different trypanosomes obtained: --saturated fatty acids T.b.b. greater than T.b.g. greater than T.b.r., --oleic series (omega 9) T.b.g. = T.b.r. greater than T.b.b., --linoleic series (omega 6) T.b.r. greater than T.b.g. greater than T.b.b., --linolenic series (omega 3) T.b.g. greater than T.b.b. greater than T.b.r.

Toxoplasma gondii strains are usually defined by biological parameters such as pathogenicity in mice. A characterization of toxoplasma strains by biochemical techniques has not been reported. In this study, extracts of tachyzoites of 7 toxoplasma strains were compared on the basis of their isoenzyme patterns for 39 enzymes by means of isoelectrofocusing in polyacrylamide gels. Eighteen enzymes gave clear and reproducible bands. Of these, 14 had identical electrophoretic patterns for all strains. Two different isoenzyme types were found for the enzymes aspartate aminotransferase, glutathione reductase, glucose phosphate isomerase, and amylase. This allowed the description of 3 isoenzyme pattern groups among the 7 toxoplasma strains. The possible relationship between biological behavior and isoenzyme pattern groups is discussed.