Triclosan and triclosan-loaded liposomal nanoparticles in the treatment of acute experimental toxoplasmosis.

Efficacy of triclosan (TS) and TS-loaded liposomes against the virulent strain of Toxoplasma gondii (T. gondii) was evaluated. Swiss albino mice were intraperitoneally infected with 10(4) tachyzoites of RH HXGPRT(-) strain of T. gondii, then were orally treated with 150 mg/kg TS or 100 mg/kg TS liposomes twice daily for 4 days. Mice mortality, peritoneal and liver parasite burdens, viability, infectivity and ultrastructural changes of peritoneal tachyzoites of infected treated mice were studied, in comparison with those of infected non-treated controls. Drug safety was biochemically assessed by measuring liver enzymes and thyroxin. Both TS and TS liposomes induced significant reduction in mice mortality, parasite burden, viability and infectivity of tachyzoites harvested from infected treated mice. Scanning electron microscopy of treated tachyzoites showed distorted shapes, reduced sizes, irregularities, surface protrusions, erosions and peeling besides apical region distortion. Transmission electron microscopy showed that treated tachyzoites were intracellularly distorted, had cytoplasmic vacuolation, discontinuous plasma membranes, nuclear abnormalities and disrupted internal structures. Besides, in TS liposomes-treated subgroup, most tachyzoites were seen intracellularly with complete disintegration of the parasite plasma and nuclear membranes, with complete destruction of the internal structures. Biochemical safety of TS and TS liposomes was proven. Accordingly, TS can be considered as a promising alternative to the standard therapy for treating acute murine toxoplasmosis. Liposomal formulation of TS enhanced its efficacy and allowed its use in a lower dose.

Preventive prospective of triclosan and triclosan-liposomal nanoparticles against experimental infection with a cystogenic ME49 strain of Toxoplasma gondii.

The preventative effect of triclosan (TS) and TS liposomal nanoparticles was studied on the early establishment of chronic infection with Toxoplasma gondii (T. gondii). Swiss albino mice were orally infected with 10 cysts of avirulent ME49 strain of T. gondii, and 2 weeks later they were orally treated with dual daily doses of 200mg/kg and 120 mg/kg TS and TS liposomes for 30 days; respectively. Effect of TS and TS liposomes was parasitologically and ultrastructurally evaluated, versus infected non-treated control. Their safety was biochemically assessed. Parasitologically, both TS and TS liposomes induced significant reduction in mice mortality, brain parasite burden and infectivity of cysts obtained from the brains of treated mice. Ultrastructurally, scanning electron microscopy of cysts obtained from infected mice treated with either TS or TS liposomes showed surface irregularities, protrusions and depressions. Transmission electron microscopy revealed disintegration of the cyst wall and vacuolation of the bradyzoites with disintegration of plasma membranes of both cysts and bradyzoites whether treated with TS or TS liposomes. Biochemical study reflected the safety of the TS and TS liposomes. Therefore, TS proved an effective, promising and safe preventive drug against early establishment of chronic toxoplasmosis. Loading TS on liposomes marginally enhanced its efficacy against T. gondii cysts yet allowed its use in a lower dose.

Disinfection efficacy of sodium dichloroisocyanurate (NADCC) against common food-borne intestinal protozoa.

The present study was conducted to investigate the efficacy of sodium dichloroisocyanurate (NaDCC) on the infective stages of common food-borne intestinal protozoa; Entamoeba histolytica (E. histolytica), Giardia lamblia (G. lamblia), Cryptosporidium, Cyclospora and Microsporidia; beside its effect on raw green vegetables and fruits. Parasites, isolated from stool of patients with diarrhea or dysentery, were exposed to NaDCC solution (1g/l) for one and two hours. Disinfection effect of NaDCC was assessed by in-vitro viability, using trypan blue stain, and infectivity bioassay in laboratory animals as indicated by fecal and intestinal parasitic counts. Raw vegetables and fruits were dipped in NaDCC solution in the same concentration and exposure time as used for treatment of the parasites. Results revealed statistically significant reductions in viability and infectivity of all examined parasites indicating their susceptibility to NaDCC. Relative variations in susceptibility were revealed; E. histolytica and G. lamblia were most susceptible (100% reduction) followed by Microsporidia then Cryptospridium and Cyclospora. NaDCC did not affect the consistency, color, taste or flavor of raw green vegetables and fruits. The proved efficacy of NaDCC, in cheap and convenient dry tablet form, makes it a promising tool in decontaminating raw vegetables and fruits from food-borne protozoan parasites at household and restaurant levels as well as in catering and fresh produce industry. It is also recommended for disinfection of food preparation surfaces and equipment.

The utility of direct agglutination (DAT) and fast agglutination screening (FAST) tests in serodiagnosis of experimental microsporidiosis.

The present study was designed to evaluate the efficiency of two serodiagnostic tests; the direct agglutination test (DAT) and the fast agglutination screening test (FAST) in the diagnosis of Microsporidia in experimentally infected mice and to differentiate between different species of the parasite. The swiss albino mice were divided into non infected control and infected experimental groups which were further subdivided into ten subgroups. Ten samples of microsporidial spores were isolated from ten human stools and each one was used to infect each subgroup of mice. Stool and sera were collected weekly from each subgroup from the 1st to the 4th week post infection (PI). DAT & FAST tests, using antigen prepared from the different species of microsporidial spores were used to detect antibodies in sera of different mice subgroups. The cross reactivity of microsporidial spores with the antibodies of Cyclospora cyatenensis and Cryptosporidium parvum was investigated by DAT & FAST. The results proved that DAT & FAST were effective in detecting microsporidial antibodies in sera of experimentally infected mice from the 2nd week PI till the end of the study, without cross reactivity with C. cyatenensis or C. parvum. They failed to differentiate between different Microspoiridia species used but, they gave good interpretation and they were specific and sensitive, and did not need sophisticated equipments.

Impact of several control measures on the encysted metacercariae of heterophyids.

The present study evaluated the effect of temperature, chemicals and microwave irradiation on the viability and infectivity of encysted metacercariae (EMC) of Pygidiopsis genata in fish. Flesh of infected fish was divided into two groups; control (GI) and experimental (GII). GII was subdivided into IIa: exposed to -4 degrees C & -20 degrees C for different periods, IIb: marinated in sodium chloride, acetic and citric acid at different concentrations and exposure times and IIc: subjected to microwave irradiation for 20 seconds. Assessment of the effect of these factors was by studying the viability and infectivity of EMC after isolation from the fish. The ultrastructure change was studied by scanning electron microscope (SEM), in comparison with control. The results showed that the highest significant reduction in the EMC viability and infectivity was detected in those exposed to microwave irradiation (100%). SEM examination showed distortion in the shape of microwave-treated EMC with change in the surface nature. Freezing of EMC at -4 degrees C & -20 degrees C for 10 days at either temperature was sufficient to abolish their infectivity, although some were remained viable. Soaking of flesh in salt or acids reduced EMC viability and infectivity. So, microwave irradiation proved prophylactic for EMC.

Effect of artesunate on Toxoplasma gondii: in vitro and in vivo studies.

The effect of Artesunate (As) on Toxoplasma gondii (T. gondii) in vitro and in vivo was studied. In vitro, tachyzoites of RH strain were exposed to As in a concentration of 2 microg/ml for 72 hours. The assessment of As effect was carried out by studying the viability, infectivity and ultrastructure changes of treated tachyzoites by scanning electron microscope (SEM). In the in vivo study, Swiss albino mice were infected intraperitoneally with tachyzoites of T. gondii RH strain, then orally treated with As in a dose of 200 mg/kg for five successive days. The effect of As was evaluated by the mortality rate and survival time of the treated mice. Parasite burden, viability, infectivity and ultrastructure changes of tachyzoites harvested from the peritoneal cavities of infected treated mice as compared with infected non-treated control mice were also studied. In vitro study demonstrated a significant reduction in viability and infectivity of tachyzoites exposed to As compared with untreated controls. In vivo study, showed that treatment of infected mice with As induced a significant decrease in mortality rate and increase in survival time. There was also a significant reduction in parasite burden in infected treated mice with significant reduction in viability and infectivity of tachyzoites harvested from them as compared with infected non-treated control. SEM showed distortion in tachyzoites' shape, peeling, erosions and discontinuity in areas of surface membrane of treated tachyzoites of both in vitro and in vivo studies. So, As proved an effective and promising drug in treating acute toxoplasmosis.

Immunization against trichinellosis using microwaved larvae of Trichinela spiralis.

The present study evaluated the effect of microwave irradiation on infective larvae of Trichinella spiralis (T. spiralis) by the ultrastructure changes of the microwaved larvae (ML) using scanning electron microscope (SEM). The ML tested the ability to immunize mice against a challenge infection with T. spiralis. For the optimal dose and the best route of immunization inducing protection against challenge infection, two doses were used; 300 & 600 ML as one or two-dose regimen, each dose was given orally and intraperitoneally (IP). SEM revealed tegumental damage of the ML in the form of distortion, loss of normal fold pattern and depressions or papillae protruded from their outer surface. After administration of the ML (orally or IP) to the non-infected control mice, neither adults nor larvae were detected in the intestines or muscles respectively. This indicated loss of larvae infectivity after exposure to the microwave irradiation. Also, a significant protection against challenge infection with T. spiralis was demonstrated in experimental mice immunized by ML, orally or IP. This was assessed by a statistically significant decrease in adult and muscle larval count, compared with the non-immunized infected control. Complete protection against both adults and larvae (100%) was achieved by IP injection of two doses of 600 ML, two weeks apart. The results suggested the feasible application of the microwave irradiation on meat for its decontamination from T. spiralis larvae. Such a method might be a promising a prophylaxis vaccine against trichinellosis in animals and/or humans.

The efficacy of antihelminthic compound; Clorsulon against experimental Schistosoma mansoni infection.

The efficacy of Clorsulon (CLS) against experimental schistosomiasis mansoni, using Praziquantel (PZQ) as a therapeutic control was evaluated. Swiss Albino mice were divided into infected non-treated control, PZQ-treated group given a single dose of 500 mg/kg four weeks post infection (PI), and infected mice treated with single, double, and triple doses of 5 mg/kg CLS per dose, one week apart starting from the 4th week PI. All animals were perfused for adults count. Parts of livers and intestines were examined for granulomata number and sizes. Pathological changes in hepatic parenchyma by H&E and Masson trichrome stains were also examined. Results revealed that a single treatment with PZQ caused a significant percentage reduction (%R) of worm load (92.68%), mean egg count in liver and intestine (91.20 & 94.01% respectively), and mean size of liver granulomata was reduced (92.06%). Regarding CLS, the worm burden was reduced proportionally with number of doses given; 87.80, 96.34 & 97.56% in single, double and triple exposures successively. Egg count in liver was decreased by 85.90, 97.01 & 96.23% respectively in treated mice. Number of intestinal granulomata was decreased by 85.28, 94.24 & 95.49% in a similar way. Size of hepatic granulomata was decreased by 89.02, 94.51 & 95.05% by 1, 2 & 3 doses consecutively. All parameters reflected non significant difference between 2 & 3 dose of CLS. The results were critically discussed.

Influence of the antioxidant drug (Antox) on experimental giardiasis and microsporidiosis.

The effect of antioxidant (Antox) on Giardia lamblia and Microsporidium sp. in rats and mice respectively was studied. Parasitologic effect was assessed by the mean parasitic count in infected animals' stool treated and non-treated, and infection intensity in stained section. Biochemical by measuring activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), myeloperoxidase (MPO) levels and cytokine induced neutrophil chemoattractant-1 (CINC-1) in intestinal homogenates in these animals as shown by cell injury, lipid peroxidation and neutrophil infiltrations. The present results showed that Antox significantly exacerbated G. lamblia and Microsporidium sp. This was manifested by a significant increase in number of G. lamblia cysts and trophozoites in stool and intestinal sections of treated infected rats. Also, microsporidian spores were significantly higher in stool of treated infected mice and infection intensity increased in the intestinal sections. The biochemical study showed a significantly higher degree of cell injury, lipid peroxidation and intestinal neutrophils accumulation in non-treated infected animals whether with G. lamblia or microsporidia. The changes reduced after treatment in giardiasis but none in microsporidiosis. The results were tabulated photographed, and critically discussed.

Effect of Schistosoma mansoni infection on physiological gastrointestinal transit and contractility.

The work aimed to study the effect of Schistosoma mansoni (S. mansoni) on gastrointestinal transit and contractility of the colonic muscles of two subgroups of experimental mice, infected by 50 & 200 cercaria/mouse respevtively, at 8th & 12th week postinfection (PI). In addition, the histopathologic changes in the colon, and the immunological changes of the host were studied at different durations. At 8th weeks PI, in both subgroups, gastrointestinal transit was statistically significant decreased, in concurrent with statistically significant increase in the colonic muscle contractility compared to the controls. The colon was inflamed as shown by mucosal inflammatory infiltrates, with large size and number of schistosomal granulomas. The serum antigen was absent, while the serum antibody was detectable at low titre. At 12th weeks PI, there was a more statistically significant decrease in gastro-intestinal transit, and increase in the colonic muscle contractility. The colon was still inflamed, but the granulomas were reduced in size and in number, with increase in the fibrocytes density. These alterations coincided with absence of serum antigen and increase in the antibody titre. All changes were more pronounced in the 2nd group of mice (200 ceraria/mouse) than the 1st one (50 cercaria/mouse). So, intestinal schistosomiasis is associated with great structural, functional and immunological changes, related to the time course and the infection intensity which may be involved in the pathogenesis and clinical manifestations of the disease.

The utility of lactoferrin in differentiating parasitic from bacterial infections.

Lactoferrin is an iron binding glycoprotein found in the 2ry granules of PMN. In order to determine the usefulness of such marker for neutrophilic activity in differentiating cases suffering from amoebic and bacillary dysentery, Schistosoma and bacterial UTI infections, we examined stool and urine specimens using anti-lactoferrin antibodies (lactoferrin latex agglutination test: LFLA), compared with different standard gold techniques. Our results demonstrated that cases with either shigllosis or UTI revealed a high lactoferrin titer which was positively correllated with the number of PMN. In addition cases with Entamoeba histolytica or S. haematobium were characterized by relatively lower inflammatory process as expressed by mild lactoferrin titer which was also correlated with the PMN count. In addition, the findings of the present work indicated that LFLA was sensitive and specific when used alone and its sensitivity was augmented after coupling with other simple indirect methods of diagnosis. In conclusion, results described the reliability of using LFLA as a simple, rapid, sensitive method in differentiating, certain parasitic from bacterial diseases.

Congenital trichinellosis in experimentally infected mice.

The present study aimed at allocating the time during pregnancy at which transplacental transmission of Trichinella spiralis (T. spiralis) larvae took place. Swiss albino mice were infected at different durations of pregnancy; five days before mating, on gestation day zero and five days after mating. Furthermore, to study the effect of immunosuppression on transplacental transmission, half of the experimental mice were immunosuppressed using cyclophosphamide drug (Endoxan). The percentage of infected uteri, embryos and placentas and the mean larval count were calculated on day 8 post infection (PI). Moreover, the percentage of infected offspring and the mean larval count in their muscles were estimated on day 30 PI. The results of the present study revealed that, transplacental transmission of T. spiralis could occur in offspring of mice when their mothers are infected before or after pregnancy. This was documented by the presence of larvae in the muscles of offspring. However, the rate of this transmission increased when the mothers are infected at late pregnancy whether they were immunosuppressed or not. The administration of the immunosuppressive drug whether before or after pregnancy increased the rate of infection and the mean larval count in both uteri of mothers and muscles of their offspring. A higher percentage of abortion was demonstrated in females infected before mating in different studied groups.

The effect of potassium permanganate and sodium dichloroisocyanurate on metacercariae of Fasciola gigantica.

Batches of encysted metacercariae of F. gigantica, adhered to transparent polyethylene sheets, were treated with KMnO4, while others were treated with NaDCC at specific concentrations and exposure times. Assessment of the effects was carried out by the detached percentage and viable metacercariae and by scanning electron microscope (SEM) ultrastructure changes. In addition, their effects on leaves of green vegetables were reported. The results showed that all metacercariae were detached and were dead by exposure to KMnO4 (96%) and NaDCC (100%) were detached from the polyethylene sheets. SEM showed that the deformities in the metacercariae soaked in NaDCC were more severe than those dipped in KMnO4. However, neither KMnO4 nor NaDCC affected the consistency, color, taste or flavor of the vegetables' leaves. The two disinfectants particularly NaDCC, proved to be safe, effective against the encysted metacercariae with no side-effects.

Vaccination against congenital toxoplasmosis.

Different types of Toxoplasma gondii vaccines were evaluated using parasitological and histopathological means to induce immunity in Swiss pregnant mice and their pups against the challenge with virulent RH strain. Immunization was performed before mating by using live cyst vaccines (LCV), LCV-IL-2 combination, irradiated cyst vaccine (ICV) and ICV-IL-2 combination. It was demonstrated that pre-immunization with the current vaccines offered significant protection of both dams and pups. The highest level of protection was noticed in mice which received LCV-IL-2, followed by ICV-IL-2, then LCV and the least protection was elicited in dams immunized with ICV alone. The results threw light on the possibility of applying such vaccines not only in mice but also in other mammalian hosts including human.

Bacterial-parasite interaction between Salmonella and each of Fasciola gigantica and Trichinella spiralis.

The possibility of bacterial-parasite interaction between Salmonella typhimurium and the surface of each of Fasciola gigantica metacercariae and Trichinella spiralis larvae was investigated in vitro. Two studies were carried out. In the first, S. typhimurium were incubated in vitro with the metacercariae of F. gigantica. In the second, S. typhimurium was incubated with larvae of T. spiralis. The interactions of S. typhimurium with each of F. gigantica metacercariae and T. spiralis larvae were studied by scanning electron microscope (SEM). In the first study, numerous bacilli were found adhered to the metacercariae surface. In the second study, no S. typhimurium was observed on the wall of T. spiralis larvae. The results indicated that only F. gigantica metacercariae act as a carrier for S. typhimurium with the possibility of occurrence of mixed infections with both organisms. So, both fascioliasis and salmonellosis must be treated concomitantly.