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PubMed2006

The relative stability of chronic Isospora sylvianthina (Protozoa: Apicomplexa) infection in blackcaps (Sylvia atricapilla): evaluation of a simplified method of estimating isosporan infection intensity in passerine birds.

Estimation of intensity of coccidia infection in wild birds is essential for the studies of the parasite impact on birds' natural populations. In this paper I propose a method for quantification of coccidia oocyst output from passerine birds applicable in field investigations because it is based on one faeces droplet per bird only. This method was checked under controlled laboratory conditions on blackcaps, chronically infected with Isospora sylvianthina, and was proved to be sensitive enough for the detection of between-individual differences in parasite load. I also show that individual variation in the intensity of isosporan infection in captive blackcaps is relatively stable in time, both in the scale of a few consecutive hours and in that of consecutive days. Hence, the study shows that, in passerine birds, single measurements of oocyst production, when collected in the proper time of day, can be used to characterise some more permanent aspects of an individual's coccidia infection status.

Animals↗
PubMed2006

Effect of oregano (Origanum vulgare L.) and thyme (Thymus vulgaris L.) essential oils on Trypanosoma cruzi (Protozoa: Kinetoplastida) growth and ultrastructure.

In the present work, we have investigated the effect of essential oils obtained from Origanum vulgare L. (oregano) and Thymus vulgaris L. (thyme) on growth and ultrastructure of diverse evolutive forms of Trypanosoma cruzi. Culture epimastigotes and bloodstream trypomastigotes were incubated for 24 h with different concentrations of oregano or thyme essential oils and with thymol (the main constituent of thyme), and the inhibitory concentration (IC)(50) was determined by cell counting. Crude extract of oregano essential oil inhibited epimastigote growth (IC(50)/24 h = 175 microg/ml) and also induced trypomastigote lysis (IC(50)/24 h = 115 microg/ml). Thyme essential oil presented IC(50)/24 h values of 77 microg/ml for epimastigotes and 38 mug/ml for trypomastigotes, while treatment with thymol resulted in an IC(50)/24 h of 62 microg/ml for epimastigotes and 53 microg/ml for trypomastigotes. Scanning electron microscopy of treated cells showed few morphological alterations at the plasma membrane. Observation by transmission electron microscopy showed cytoplasmic swelling with occasional morphological alterations in plasma and flagellar membrane. Our data indicate that oregano and thyme essential oils are effective against T. cruzi, with higher activity of thyme, and that thymol may be the main component responsible for the trypanocidal activity.

Animals↗
PubMed2000

Pathological effects and reduced survival in Rhipicephalus appendiculatus ticks infected with Theileria parva protozoa.

Pathological effects have been demonstrated in a number of arthropod species as a consequence of parasitic infection. This is usually manifest as reduced arthropod survival and/or fecundity. This paper describes the detrimental effects the protozoan parasite, Theileria parva has on Rhipicephalus appendiculatus ticks. R. appendiculatus ticks were dissected and sectioned at regular intervals during their nymph to adult moult after detaching from a T. parva infected calf, and assessed by light and electron microscopy. The reproductive capacity of the T. parva infected ticks was also compared with that of control, uninfected ticks. The number of T. parva forms seen during the ticks' moult were recorded and showed a substantial reduction as the moult progressed. A non-linear relationship between piroplasm ingestion by the engorged nymph and eventual adult salivary gland infection levels was shown. Tick gut and salivary gland pathology was noted at various stages throughout the moult and correlated with the parasite burdens in the affected organs at those timepoints. The reproductive performance of infected ticks was greatly impaired compared to controls. Infected female ticks had longer bloodmeal engorgement times, reduced bloodmeal volumes, smaller egg batch weights and greatly decreased egg hatching success. The pathological effects are discussed in relation to parasite population dynamics within the ticks and compared with similar examples of pathology evidenced with other parasite infected arthropod species.

Animals↗
PubMed1996

Light microscopic description of Eimeria sparis sp. nov. and Goussia sparis sp. nov. (Protozoa:Apicomplexa) from Sparus aurata L. (Pisces: Teleostei).

Two new species of Coccidia, Eimeria sparis sp. nov. and Goussia sparis sp. nov., were found in the intestine of Sparus aurata from different culture systems of Spain. These are the first coccidian species described from this host. E. sparis is distinguished from other Eimeria spp. from Perciformes in the size and shape of the sporocysts, which measure 6-9.7 (mean = 7.78, SD = 1.33) x4-6.5 (5.3 +/- 0.92) microns, and in the Stieda-like body. Mature oocysts, spherical or subspherical, measure 9.4-14.3 (11.88 +/- 1.85) microns. G. sparis differs from other Goussia spp. from fish of the Mediterranean area in the size and shape of the oocysts and sporocysts as well as in the location. Mature oocysts measure 16-21 (17.4 +/- 1.5) x 13-18 (14.4 +/- 1.7) microns and sporocysts, 8.6-10.3 (9.5 +/- 0.5) x 5.7-7.4 (mean 6.5 +/- 0.5) microns. The different stages of merogony, gamogony, and sporogony of both species were examined at the light-microscope level in fresh material and histology specimens. Sporulation was endogenous in E. sparis and exogenous in G. sparis.

Animals↗
PubMed1996

Ultrastructure of the wall of the sporophorous vesicle during sporogony of Pleistophora mirandellae (Protozoa:Microspora).

The wall of the younger sporophorous vesicle (enclosing the sporogogonial plasmodium) of Pleistophora mirandellae Vaney and Conte, 1901 is composed of a membranous labyrinth, about 0.3-0.6 microns high, interwoven with host cell cytoplasm. There is electron-opaque matter within the partitions of the labyrinth. At the onset of plasmotomy, the partitions of the labyrinth become shorter and then possibly due to stretching of the wall and withdrawal of the membranes, the electron-opaque matter is ejected to the lumen side of the wall and the partitions disappear. Only cisterna-like remains of the partitions are observable outside the electron-opaque layer. The thickness of walls in vesicles with ripe spores can be even less than 100 nm.

Animals↗
PubMed1997

Ultrastructure and cytochemistry study of Goussia sparis (Protozoa: Apicomplexa) stages from the intestine of the gilthead sea bream Sparus aurata L. (Pisces: Teleostei).

The ultrastructure and cytochemistry of merogonial and gamogonial stages and early unsporulated oocysts of Goussia sparis in the intestine of Sparus aurata were studied. The typical pellicle was observed in some stages. The different stages might appear in intraepithelial or supraepithelial positions, but they were always intracellular. First steps of two apparently different endomerogonies were observed in intra- and supraepithelial positions, respectively. An apparent ectomerogony also occurred in supraepithelial stages. Developing macrogamonts showed surface invaginations and were densely packed with ribosomes, well-developed rough endoplasmic reticulum, mitochondria, amylopectin granules, lipidic droplets, and wall-forming-like bodies. The latter could participate in the formation of the oocyst wall. Abundant and large mitochondria, together with residual nuclei, appeared in advanced microgamonts. Microgametes showed two flagella with microtubul arranged according to the typical pattern. An increase in polysaccharide content was observed with coccidian development, reaching a maximum in zygotes and unsporulated oocysts.

Amylopectin↗
PubMed1997

Ultrastructure and cytochemistry study of Eimeria sparis (Protozoa:Apicomplexa) stages from the intestine of gilthead sea bream Sparus aurata L. (Pisces:teleostei).

The ultrastructure and cytochemistry of merogonial, gamogonial, and early sporogonial stages of Eimeria sparis in the intestine of Sparus aurata were studied. Mature stages showed the typical pellicle, which was lost in some transitional stages. An apparent unit membrane was seen in some immature stages. A parasitophorous vacuole, sometimes with membrane vesicular invaginations, was usually observed. We propose that the stages located over the epithelium and the so-called epicellular stages be termed supraepithelial stages. Endomerogony was observed in intraepithelial and supraepithelial positions. Intraepithelial stages apparently starting ectomerogony were also detected. Electron-dense granules similar to wall-forming-like bodies of types 1 and 2 were observed. Microgametes exhibited two flagella. Cytochemistry study revealed scarce polysaccharides, if any, in merogonial stages and in microgamonts. The occurrence of polysaccharides and amylopectin granules increased progressively in macrogamonts, macrogametes, zygotes, and early oocysts. Lipidic droplets were scarce of absent in merogonial stages and abundant in maturing macrogamonts. Some glycoproteins were demonstrated in certain merogonial stages.

Animals↗
PubMed1997

Fine structure and isozymic characterization of trichomonadid protozoa.

Tritrichomonas suis and T. foetus are characterized herein at the ultrastructural and biochemical levels. Microcinematography and measurements, scanning and transmission electron microscopy, cytochemistry for carbohydrate detection (Thiéry technique), and isozyme electrophoresis analysis were performed. In all, 11 different strains from 5 species of parasites were studied (T. foetus, T. suis, Trichomonas gallinae, T. vaginalis, and Monocercomonas sp.). A total of 11 enzymes were scored. Fine-structure study using scanning and transmission electron microscopy demonstrated that T. suis and T. foetus are identical morphologically. The high degree of isozymatic similarity noted between T. suis and T. foetus is consistent with the hypothesis that they may be different strains of the same species.

Animals↗
PubMed1997

Use of the polymerase chain reaction for identification and quantification of Theileria parva protozoa in Rhipicephalus appendiculatus ticks.

The polymerase chain reaction (PCR) was adapted for detection of Theileria parva sporoblasts in Rhipicephalus appendiculatus ticks by comparison with staining of histological preparations of ticks with methyl green and pyronin (MGP). Two 32mer primers (IL174 and IL179) were used to amplify Theileria parva (Muguga isolate) DNA from the TPR 1 region of the genome by the PCR. Detection of T. parva was carried out with dissected salivary glands and whole ticks preserved in ethanol. Adult ticks which fed as nymphs on a T. parva infected calf were used in three experiments. Firstly, 70 whole ticks divided into 7 batches representing the rising and falling parasitaemia of the calf were used to show that detection of infection by the PCR was significantly correlated with MGP staining. Secondly, 120 dissected ticks were used from 4 different batches representative of the overall infection profile within the ticks to show a high correlation between PCR quantification within tick salivary glands and MGP count data of the paired gland. Thirdly, 120 ticks were used in batches selected for high and low infections. Bloodmeal contaminants from partially fed adult ticks, present in 60 out of the 120 ticks used, did not inhibit the PCR amplification of T. parva DNA. This experiment also showed a great increase in infection detection in partially fed batches of ticks compared to the untreated batches.

Animals↗
PubMed1997

Ceratomyxa sparusaurati (Protozoa:Myxosporea) infections in cultured gilthead sea bream Sparus aurata (Pisces:Teleostei) from Spain: aspects of the host-parasite relationship.

Ceratomyxa sparusaurati infection was studied in gilthead sea bream from different mariculture systems of Spain. Culture conditions were found to influence the infection dynamics. Total prevalences ranged from 0 in a closed system to 59.9% in a Mediterranean semi-intensive farm. Prevalence was significantly lower in summer in a restricted group from the latter system, but no clear seasonal pattern was observed in the remaining fish groups in any system. A statistically significant dependence between infection prevalence and host weight was observed in some fish groups. Different degrees of histopathological damage were noted in the infected gallbladders, mainly involving swelling, vacuolization, and sloughing of the epithelial cells. Transmission electron microscope observations of the infected tissues demonstrated a characteristic protrusion of the epithelial cell surface and mitochondrial alterations. In fish from stocks showing external disease signs and trickling mortalities, parasite stages invaded other organs and were responsible for cell-mediated host reaction and important tissue injuries. Therefore, C. sparusaurati can be considered a potential threat for some Sparus aurata-growing systems.

Animals↗
PubMed1998

Comparative genetic analysis of tritrichomonadid protozoa by the random amplified polymorphic DNA technique.

The taxonomic classification within the genus Tritrichomonas is a subject of controversy, and, potentially, separation of the tritrichomonads from cattle and swine on the species level is not valid. To tackle this hypothesis we comparatively assessed several isolates of protozoan parasites from the three Tritrichomonas species T. foetus, T. suis, and T. mobilensis by the RAPD (random amplified polymorphic DNA) technique. In this method with 20 different primers, all T. foetus and T. suis isolates resulted in identical genomic fingerprints, thus yielding additional evidence for the genetic identity of T. foetus and T. suis. In contrast, it turned out that the species T. mobilensis isolated from the squirrel monkey is genetically distinct and can clearly be discriminated from the other tritrichomonads. Consequently, the results obtained in this study support a possible future revision of the taxonomic classification of the genus Tritrichomonas.

Animals↗
PubMed1998

Trypanosomatid protozoa in plants of southeastern Spain: characterization by analysis of isoenzymes, kinetoplast DNA, and metabolic behavior.

Three flagellates of the family Trypanosomatidae were isolated from mango fruits (Mangifera indica) and from the stems of clover (Trifolium glomeratum) and Amaranth (Amaranthus retroflexus) in southeastern Spain and were adapted to in vitro culture in monophase media. The parasites showed an ultrastructural pattern similar to that of other species of the genus Phytomonas. Mango and clover isolates differed from amaranth isolates in ultrastructural terms. The isolates were characterized by isoenzymatic analysis and by kDNA analysis using five different restriction endonucleases. With eight of the nine enzymatic systems, mango and clover isolates were distinguished from those of amaranth. Nevertheless, with the enzymes malate dehydrogenase and superoxide dismutase, flagellates isolated from clover were differentiated from those isolated from mango. Electrophoretic and restriction-endonuclease analysis of kDNA minicircles showed similar restriction cleavage patterns for the isolates from mango and clover, whereas the patterns of the amaranth isolates differed. The results of the present study confirm that the strains isolated from mango and clover constitute a phylogenetically closely related group of plant trypanosomatids, which is more distantly related to the strain isolated from amaranth. The similarities in the results obtained for isolates from mango and clover foliage, on the one hand, and those obtained from tomato and cherimoya fruits (studied previously), on the other, as well as the geographic proximity of the different plants support the contention that only one strain is involved, albeit one strain that can parasitize different plants. Furthermore, some of the plants appear to act as reservoirs for the parasites. On the other hand, the metabolism studies using [1H]-nuclear magnetic resonance spectroscopy did not reveal that the catabolism of Phytomonas in general follows a pattern common to all the species or isolates. Phytomonas are incapable of completely degrading glucose, excreting a large part of their carbon skeleton into the medium as fermentative metabolites (acetate, ethanol, glycine, glycerol, and succinate).

Animals↗
PubMed1998

Biological effects of gamma-irradiation on laboratory and field isolates of Eimeria tenella (Protozoa; Coccidia).

Sporulated oocysts of a field strain (FS-111) and a laboratory strain (WIS) of Eimeria tenella were exposed to 0, 50, 100, 150, or 200 Gy of gamma-radiation from a 60Co source. Irradiated oocysts of WIS and FS-111 were not significantly more fragile after irradiation as shown by the release of sporocysts after 5-105 s of vortex agitation with glass beads. Excystation was normal in both strains after treatment of the sporocysts with trypsin and sodium taurodeoxycholate, even in groups exposed to 200 Gy of radiation. Sporozoite release from irradiated sporocysts was more rapid than that from unirradiated sporocysts, primarily because of a shorter lag phase during the first 30 min. Irradiated sporozoites were slower to parasitize cultured chick kidney cells than were control sporozoites (4 h postinoculation), but after 24 h there was no significant difference (P < 0.05) between irradiated and control groups except for the WIS treated with 200 Gy. After 48 h, developing schizonts were reduced by 77-94% on exposure to 50-200 Gy. Strain FS-111 did not develop as well as WIS in vitro, but the effect of irradiation was similar. When irradiated oocysts of WIS or FS-111 were inoculated into chickens the prepatent period was unaffected, but fewer oocysts were produced, lesion scores were lower, and the weight gain was less strongly affected in proportion to the doses of radiation. These results suggest that the effects of radiation damage were largely confined to the mechanism of nuclear and cellular reproduction rather than other physiological processes.

Animals↗
PubMed2001

Autofluorescence microscopy for the detection of nematode eggs and protozoa, in particular Isospora suis, in swine faeces.

Parasites from swine faeces were examined for autofluorescence. Oocysts of Eimeria polita, E. scabra and Isospora suis, cysts of Balantidium coli and eggs of Oesophagostomum dentatum, Strongyloides ransomi and Trichuris suis (but not those of Ascaris suum) emitted light after excitation with UV light. I. suis oocyst counts in McMaster chambers utilising autofluorescence were compared to those from conventional bright field microscopy. Similarly, faecal smears containing I. suis were examined using the same techniques. Autofluorescence was superior to bright field microscopy in detecting oocysts after flotation and was highly significantly more sensitive when direct smears were examined.

Animals↗
PubMed2001

Chemotherapeutic approaches to protozoa: haemosporina--current level of knowledge and outlook.

Chloroquine and mefloquine are available for prophylactic treatment in malaria, against a background of the burgeoning problem of resistance developing to chloroquine and related drugs (Mehlhorn and Schrevel 1995). For this reason, highly specific national recommendations are given out regarding prophylaxis. The option of a viable vaccine is currently not available. More new compounds are therefore urgently required, since 2-5 million of the 200 300 million infected people die each year. At the moment, atovaquone and artemisinin derivatives are of great interest, as are drug combinations such as atovaquone/proguanil (since 1997), artemether/ benflumetol (since 1998?; Ciba-Geigy, patent WO9202217) and chlorproguanil/dapsone (since 2000?), as these compounds are also effective against multi-resistant strains of Plasmodium falciparum (Tables 1, 2; Croft 1997; Wang 1997). Pyronaridin (since 2000?) has been discovered in a Chinese academy and is in clinical trials (Trouiller and Olliaro 1998; Pecoul et al. 1999).

Animals↗
PubMed2001

Chemotherapeutic approaches to protozoa: Coccidiae--current level of knowledge and outlook.

Progress in the treatment and prophylaxis of cyst-forming coccidial infections (Neospora, Sarcocystis Toxoplasma) and Cryptosporidium infections has been limited (Table 1: Haberkorn 1996: Croft 1997: Wang 1997). However, new possibilities have been opened up in the treatment of Eimeria-induced coccidiosis in poultry and mammals. due to improvements in treatment and, or metaphylaxis. A new polyether antibiotic. semduramycin, has recently been added to the range of effective prophylactic preparations. The development of resistance to anticoccidial agents is now posing similar problems to those encountered with malaria, coccidiosis in poultry being particularly affected. Because no new active ingredient from a new family of chemical substances has been developed for more than 10 years, the following approaches are being adopted to get round this problem: the use of older preparations which have not been used for a long time, the introduction of combinations such as narasin nicarbazin or methyl benzoquate clopidol and the alternating use of anticoccidial agents in rotation and shuttle programmes. The goal of a real alternative, i.e. vaccination, has been achieved to a certain extent in the form of live vaccines for laying hens and broiler breeders and is being practiced in some countries.

Animals↗
PubMed2001

Chemotherapeutic approaches to protozoa: kinetoplastida--current level of knowledge and outlook.

The possibilities for treating haemoflagellate infections (African trypanosomiasis) are very limited (Table 1; Mehlhorn and Schrevel 1995; Croft 1997; Hunter 1997; Wang 1997; Trouiller and Olliaro 1998). All the available drugs have severe side-effects in humans and animals. Vaccination is not really an option, in view of the wide antigen variability. At present, there are several drug combinations in clinical trials: suramin/eflornithine, suramin/metronidazole, suramin/pentamidine, melarsoprol/pentamidine, melarsoprol/nifurtimox and nifurtimox/eflornithine. Some of these combinations were successful in treating resistant Trypanosoma brucei rhodesiense and/or T. b. gambiense infections (Keiser et al. 2001). In leishmaniasis, the tendency is still to resort to the old antimony compounds, with their severe side effects. At present, miltefosine is in clinical phase and is the first oral drug against visceral leishmaniasis (Jha et al. 1999). Two drugs are currently used against Chagas' disease, although these do not cure chronic effects. There is no prospect of novel drugs in this indication either (Pecoul et al. 1999; Morel 2000).

Animals↗
PubMed2001

Chemotherapeutic approaches to protozoa: Giardia, Trichomonas and Entamoeba--current level of knowledge and outlook.

The situation regarding the treatment of human Giardia and Trichomonas infections and the intestinal and tissue stages of Entamoeba histolytica with metronidazole and other 5-nitroimidazoles is currently satisfactory (Table 1; Mehlhorn 2000). Following correct and rapid diagnosis, the parasites are eliminated reliably and completely. The situation in cases of infection with Acanthamoeba (often involving the eyes) or with Naegleria (often involving the brain) is serious, however. In both cases, there is no drug of choice available. Treatment consists of relieving the symptoms and/or preventing local degeneration.

Animals↗