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At least 253 records · Page 14Linked to original sources
PubMed2005

Preventing parasites in cats.

The monthly administration of broad-spectrum heartworm medications can effectively prevent a variety of internal and external parasitic diseases in cats. Although not every parasite can be stopped, many of the common feline parasites are susceptible to these agents. This article discusses the epidemiology and prevention strategies for those parasites that can be controlled by the administration of ivermectin, milbemycin oxime, or selamectin, either alone or in conjunction with an external parasiticide.

Animals↗
PubMed2005

Molecular diagnosis and typing of Trypanosoma cruzi populations and lineages in cerebral Chagas disease in a patient with AIDS.

Trypanosoma cruzi DNA was amplified from an intracranial biopsy and peripheral blood of an HIV patient with encephalitis; this episode was indicative of AIDS and congenital Chagas disease. The analysis of a micro-satellite locus revealed a multiclonal parasite population at the brain lesion with a more complex minicircle signature than that profiled in blood using restriction fragment length polymorphism (RFLP)-PCR and low stringency single primer (LSSP) PCR. Interestingly, different sublineages of T. cruzi II were detected in blood and brain by means of spliced-leader and 24salpha ribosomal-DNA amplifications. Quantitative-competitive PCR monitored the decrease of parasitic load during treatment and secondary prophylaxis with benznidazole. The synergy between parasiticidal plus anti-retroviral treatments probably allowed the patient a longer survival than usually achieved in similar episodes. This is the first case report demonstrating a differential distribution of natural parasite populations and sublineages in Chagas disease reactivation, showing the proliferation of cerebral variants not detectable in peripheral blood.

AIDS-Related Opportunistic Infections↗
PubMed2006

Endectocide use in cattle and fecal residues: environmental effects in Canada.

Endectocides, or macrocyclic lactones, are veterinary parasiticides used globally to control nematodes and arthropods affecting livestock. Cattle treated with these products fecally excrete residues that are toxic to dung-inhabiting insects, including species that accelerate dung degradation. Concerns have been raised that use of endectocides may reduce insect diversity and cause the accumulation of undegraded dung on pastures. This article synthesizes the results of studies performed to assess the nontarget effects of endectocide use in Canada. Residues reduce insect activity in dung of treated cattle for weeks to months after application. The duration of effect is influenced by several factors, including insect species and product. For example, in terms of toxicity, doramectin > ivermectin approximately equal to eprinomectin >> moxidectin. Reduced insect activity may retard dung degradation. Within the framework of regional conditions and management practices, endectocide use in Canada is unlikely to pose a significant widespread threat to the environment. Nevertheless, nontarget effects may be of concern to individual cow-calf operators, particularly those treating cattle in the spring. This synthesis, the first assessment of the nontarget effects of endectocide use in Canada, emphasizes the importance of presenting findings within an appropriate context.

Animals↗
PubMed2006

[Epidemiological surveillance of cystic echinococcosis in dogs, sheep farms and humans in the Rio Negro Province].

The surveillance of infection for Echinococcus granulosus in the Province of Rio Negro during 1980-2002 included serological and ultrasonographic screening in humans and arecoline test in dogs. In lieu of the limitations of the arecoline test the proposal was to supplant that test for the copro ELISA-copro/Western Blot complex applied to feces collected from the environment. The objective was to compare the pros and cons of the two tests and to evaluate the human and the canine infection prevalence. The working area encompassed 7 Departments with systematic canine parasiticide activities (Program Area) and 4 Departments, not endemic, as Control Area. The arecoline test was applied to the dogs in assembled groups with the voluntary participation of their owners (not randomized sampling). Samples for the detection of coproantigens were obtained from sheep farms selected at random and analyzed by the complex copro-ELISA /Western Blot. Prevalence in man was determined by screening the school population (6 to 14 years old) by ultrasound, and by means of the compulsory notification of cases from the official system. Dogs (416) were tested with arecoline, 365 of which belonged to the Program Area. Of these 19 (5.2%) resulted positive, while none of 51 dogs from the Control Area were positive. Samples (748) of feces were tested to detect coproantigens, obtaining 37 positive samples within the Program Area and 4 within the Control Area. Farms (271) from the livestock estate unit were evaluated, out of which 236 belonged to the Program Area, gave 32 (13.6%) positive results, while 4 (11.4%) of 35 from the Control Area resulted positive. Sonography tests (7421) were done in the Program Area detecting 40 (0.5%) carriers, while in the Control Area, over 1732 tests, 9 (0.5%) resulted positive. The arecoline test provides information about the dog prevalence while the detection of coproantigens in feces collected from the environment allowed to enhance the quality of the information, and the identification of environments where specific control activities focusing on risk must be concentrated. Also the study allowed to recognize new transmission areas.

Adolescent↗
PubMed2000

Beta 2-microglobulin and neopterin in patients with giardiasis.

The aim of the study was to evaluate serum beta 2-microglobulin (beta-2m) and neopterin (NPT) in in patients with giardiasis. Twenty-two patients with giardiasis were examined and compared with twelve healthy subjects as a control group. Serum beta-2m and NPT concentration were determined twice: at the moment of diagnosis of giardiasis and six months after antiparasitic treatment with metronidazole. It was shown that serum beta-2m concentration in patients with giardiasis was remarkably elevated. It decreased significantly, but six months after treatment it was still higher as compared to the control group. However, serum NPT before anti-parasitic treatment was slightly lower than in the control group, but after elimination of Giardia an increase of NPT concentration above control values was observed. It is concluded that Giardia infection leads to long-lasting disturbances in the immunological status of the host and may influence macrophage function and downregulate their parasiticidal effects.

Adult↗
PubMed2006

[Biological effects of toosendanin, an active ingredient of herbal vermifuge in Chinese traditional medicine].

The fact that the fruit and bark of plant belonging to family Melia could be used as digestive tract-parasiticide and agricultural insecticide was recorded about two thousand years ago in ancient China. Toosendanin (TSN, C30H38O11, FW=574), a triterpenoid derivative, was extracted from the bark of Melia toosendan Sieb. et Zucc. by Chinese scientists in 1950os and used as an ascarifuge in China instead of imported sendanin. Studies have demonstrated that TSN possesses special biological actions as well as considerable various values in scientific research, clinic medicine and agriculture. The first is that by interfering with neurotransmitter release by causing an initial facilitation, TSN eventually blocks synaptic transmission at both the neuromuscular junction and central synapses. The action might result from TSN-induced Ca(2+)-sensitivity change and final elimination of transmitter release machinery. The second is that despite sharing many similar actions with botulinum neurotoxin (BoNT) on blocking neuromuscular transmission, TSN has a markedly antibotulismic action in vivo and in vitro: TSN-treatment saves the botulism mice or monkeys from death; TSN-incubation in vitro or TSN-injection in vivo endows neuromuscular junction with a high tolerance to BoNT. Studies suggest that the antibotulismic action is achieved by preventing BoNT from approaching its enzymatic substrate, SNARE protein. The third, in recent years, it is also observed that TSN can induce differentiation and apoptosis in several cell lines, and suppress proliferation of various human cancer cells. The TSN-induced differentiation is Ca(2+)-dependent and the mitochondria-dependent apoptosis pathway is involved in the TSN-induced apoptosis. The fourth is that TSN inhibits various K(+) channels and selectively facilitates Ca(2+) current through L-type Ca(2+) channels and hence elevates [Ca(2+)](i). The TSN-induced [Ca(2+)](i) increase and overload could be responsible for the TSN-induced biphasic effect on neurotransmitter release, cell differentiation, apoptosis as well as the cytotoxicity of TSN.

Animals↗
PubMed1991

Platelet cytotoxicity against parasites.

Platelets are not restricted to hemostasis and thrombosis since they are involved in defence mechanisms especially in parasitic diseases. They express cytotoxic functions in vitro and in vivo against extra-cellular and intra-cellular parasites. The toxic process is mediated either by specific antibodies or directly by the parasite itself. As some metabolic pathways seem to be implicated both in hemostasis and in parasiticidal activity, primary hemostasis and cytotoxicity may be considered as specialized inflammatory responses.

Animals↗
PubMed1991

A purified parasite antigen (p30) mediates CD8+ T cell immunity against fatal Toxoplasma gondii infection in mice.

Induction of protective immunity against acute and chronic toxoplasmosis can be achieved using p30, the major membrane and excreted/secreted protein of Toxoplasma gondii. This protein, when administered to outbred mice in the presence of the saponin Quil A, is able to induce almost 100% protection against acute infection without evidence of intracerebral cyst development. Adoptive transfer of immune splenocytes from immunized inbred A/J mice conferred a significant level (p less than 0.001) of protection against subsequent challenge. Phenotypic analysis in outbred as well as two different strains of inbred mice (A/J and C57BL/6) demonstrated that CD8+ T cells are selectively stimulated by this immunization protocol. T cell depletion studies using specific mAb directed at either CD3+ or CD8+ T cell phenotype, followed by adoptive transfer, failed to confer protective immunity, whereas CD4+ depletion had no effect. These cytotoxic CD8+ T cells produced high titers of both IFN-gamma and IL-2. Moreover, these CD8+ T cells were directly parasiticidal against radiolabeled extracellular T. gondii, further supporting the critical immune function of these p30 Ag-specific CD8+ T cells in host immunity against T. gondii infection.

Adjuvants, Immunologic↗
PubMed1990

Veterinary use of ivermectin.

Following the development of a unique claim structure encompassing both nematode and arthropod species, ivermectin was first introduced as a veterinary parasiticide in 1981. For cattle(c), sheep(s), horses(h) and pigs(p) injectable(c,s,p), oral(c,s,h) and topical(c) products are available delivering ivermectin at 200 to 500 micrograms/kg. Efficacy extends to nematodes of the gastrointestinal and respiratory tracts, conjunctival sac and soft tissues. Among the arthropod parasites claims have been established for the biting fly Haematobia irritans(c), the screw-worm Chrysomyia bezziana(c), larvae of the oestrid flies Hypoderma spp.(c), Dermatobia hominis(c), Oestrus ovis(s) and Gastrophilus spp.(h), lice(c,p), mange mites(c,s,p) and the ticks Boophilus spp.(c) and Ornithodorus savignyi(c). In the dog two oral formulations are available for the prevention of heartworm disease caused by Dirofilaria immitis by administration of 6 micrograms/kg once monthly during the mosquito season.

Animals↗
PubMed1990

Effectiveness of arprinocid in the reduction of cryptosporidial activity in immunosuppressed rats.

Immunosuppressed rats inoculated with Cryptosporidium oocysts isolated from calves' feces were treated with arprinocid, 50 mg/kg of body weight/d. As determined from differences in the mean number of cryptosporidial developmental stages per villus in treated vs control rats, arprinocid had a substantial effect on cryptosporidial activity, which was parasitistatic instead of parasiticidal. Drug-ranging experiments indicated that arprinocid was effective at 50 and 25 mg/kg/d, but not at 12.5 mg/kg/d. These results suggest that further testing of arprinocid in different animal models, or in phase-I clinical trials, is warranted.

Adenine↗
PubMed1988

Schistosoma mansoni: effect of gossypol on infections in mice.

Gossypol, a toxic drug present in cotton seed oil, was subcutaneously injected into mice infected with Schistosoma mansoni. Injections were given daily over three 15 day-periods covering, respectively, schistosomula migration through skin and lungs, parasite establishment in the mesenteric veins and the schistosome sexual maturation phase. Worms were recovered by mesenteric perfusion and eggs were counted in livers and intestines 52 days after infection. Gossypol neither influenced schistosome development nor affected parasite fecundity. Schistosome-induced splenomegaly was not altered by gossypol, but the drug further aggravated the poor health status of the mice. In contrast to the reported activity of gossypol against other parasites, a parasiticidal activity was not detectable with schistosomes.

Animals↗
PubMed1987

Prevention of murine cerebral malaria by low-dose cyclosporin A.

The effects of cyclosporin A (CsA) were investigated in an experimental model of cerebral malaria. In this model, Plasmodium berghei ANKA-infected CBA/Ca mice develop a clinically and histologically characterized neurological syndrome which is considered to be the result of immunopathological reactions mediated by L3T4+ T cells. It was shown that CsA displayed a strong protective effect on neurological complications when given at a dose 1 mg/kg/day for 5 consecutive days (Days 4-8), which had no effect on the parasite. Paradoxically, this protection against neurological complications was not seen when parasiticidal doses were used during this limited 5-day period. A similar protective effect was observed with two CsA derivatives, C5-34 and H7-94. The mechanisms by which CsA and the two derivatives could prevent murine cerebral malaria are unknown but can be related to exquisite effects on some lymphocyte functions. In view of these results, it might be conceivable to investigate the benefits of using low doses of CsA in man, in conjunction with the classical antiparasite therapy, for the management of cerebral malaria.

Animals↗
PubMed1987

Lymphocyte migration in murine malaria during the primary patent parasitaemia of Plasmodium chabaudi infections.

Inoculation of adult C57/BC mice with 10(6) red cells infected with Plasmodium chabaudi induces an acute primary parasitaemia peaking around the 8th or 9th day and lasting 10-14 days. Concomitantly, the spleen enlarges to reach 6-7 times its normal weight by the 11th day. The major component of this increase is between day 9 and 11, due primarily to an increase in erythropoietic cells in the red pulp. Although initially the white pulp increases in size, by day 11 it shows partial lymphocyte depletion which coincides with the occurrence of massive absolute lymphocytosis in the peripheral blood. 3H-Thymidine labelling in vivo suggests that this lymphocytosis is not due to lymphocytopoiesis. Collectively, these findings suggest a redistribution of lymphocytes. Lymphocyte migration was investigated around peak parasitaemia, using enriched populations of T and B cells labelled with 51Cr. The traffic patterns of these cells were followed over 36 h. These studies show decreased uptake (or decreased retention) of T and B cells by spleens of infected mice. Concomitantly, there is increased retention of T and B cells in the liver and lungs of infected mice, suggesting a complex redistribution of these cells. Lymphocyte migration to lymph nodes was unimpaired in these animals. Similar changes in T and B cell migration do not occur in Babesia microti infections in C57/BL mice. We relate our findings to histological and histochemical changes in the liver and spleen of malarious mice and discuss the significance of these findings to immunosuppression in malaria and to the development of parasiticidal immunity.

Animals↗
PubMed1985

An unexpected response to vaccination with a purified major membrane tachyzoite antigen (P30) of Toxoplasma gondii.

A purified Toxoplasma gondii tachyzoite membrane protein (P30) and a monoclonal antibody directed against this antigen were used to immunize mice. The P30 protein has an apparent m.w. of 30,000 and is the major radioiodinated tachyzoite membrane antigen identified by human and mouse antitoxoplasma antisera. Polyclonal and monoclonal antibody to the P30 antigen are parasiticidal in the presence of human serum. A series of mice were immunized with affinity column-purified P30 protein. This produced a dose-dependent, antigen-specific IgG and IgM response. The mice were challenged with the less virulent C strain tachyzoite. Immunized mice showed a statistically significant increase in mortality over nonimmunized control mice. In addition, vaccinated mice had an increased number of intracerebral tissue cysts when compared with the control group. Similar results were obtained with passive transfer immunization by using monoclonal antibody directed against the P30 antigen. Immunofluorescence assay of brain tissue cyst bradyzoites revealed a total absence of P30 antigen. Bradyzoites were also deficient in another major tachyzoite antigen of approximate m.w. 22,000 (P22). Mouse antibradyzoite serum absorbed with tachyzoites recognized bradyzoites but failed to identify tachyzoites. This suggests that there are stage-specific bradyzoite antigens of Toxoplasma gondii.

Animals↗
PubMedDate not supplied

[Chatelguyon thermal springs and amoebiasis (author's transl)].

Châtelguyon thermal springs are an effective treatment of chronic post amoebic colitis and its side effects on gastroduodenal tract and autonomic nervous system. The high level of magnesium of these waters is the main therapeutic agent; after the cure, the intraerythrocytic magnesium level is above the standard while the Mg seric level is below. The waters might reactive the amoebiases, increasing in the same time the specific amoebic antibodies. Parasiticidal treatment must be prescribed before any cure, if patient is proved to be Entamoeba minuta or cyst carrier.

Antibodies↗
PubMed1971

Influence of parasite strain on chemotherapy of murine infections with Schistosoma mansoni.

The effectiveness of chemotherapy in human schistosomiasis varies from one area to another, and limited data from experimentally infected animals suggest inherent differences in the susceptibility of certain parasites to drugs. In the present study, groups of mice infected with each of several geographic strains of Schistosoma mansoni were treated with one of four selected drugs and parasiticidal effects were compared.Responses to treatment were generally similar among strains except in two trials involving a Puerto Rican strain that was unusually sensitive to hycanthone and relatively resistant to stibophen.Selective killing of male worms occurred consistently with lucanthone and hycanthone treatment. The use of portal perfusion rather than dissection to recover surviving worms appears to have been instrumental in allowing the relatively resistant female worms to be found, namely in the liver.The results of this study indicate that strain differences in susceptibility to drugs do occur in S. mansoni, and apparent refractoriness or unusual sensitivity encountered in the field should be evaluated in the laboratory.

Animals↗
PubMed1984

Intracellular destruction of Leishmania tropica by macrophages activated with macrophage activating factor/interferon.

Supernatants (SN) from cloned T cell lines, lymphokine secreting tumour cell lines and mixed lymphocyte culture were analysed for their ability to induce murine peritoneal exudate cell (PEC) macrophages (M phi) parasitized with Leishmania tropica to destroy the parasite. The ability of the SN to induce parasite destruction in parasitized PEC M phi correlated with their content of macrophage activating factor/interferon. Neither granulocyte-macrophage colony stimulating factor, M phi colony stimulating factor nor interleukin 2 was required for the induction of parasiticidal activity by infected PEC M phi. Similar results were also obtained using either a different Leishmania species, Leishmania enriettii, or a second source of cells: bone marrow derived macrophages.

Animals↗