Ticks, ivermectin, and experimental Chagas disease.
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Following an infestation of dogticks in kennels housing dogs used for long-term studies of the pathogenesis of Chagas disease, we examined the effect of ivermectin treatment on the dogs, ticks, trypanosome parasites, and also on triatomine vectors of Chagas disease. Ivermectin treatment was highly effective in eliminating the ticks, but showed no apparent effect on the dogs nor on their trypanosome infection. Triatominae fed on the dogs soon after ivermectin treatment showed high mortality, but this effect quickly declined for bugs fed at successive intervals after treatment. In conclusion, although ivermectin treatment may have a transient effect on peridomestic populations of Triatominae, it is not the treatment of choice for this situation. The study also showed that although the dogticks could become infected with Trypanosoma cruzi, this only occurred when feeding on dogs in the acute phase of infection, and there was no evidence of subsequent parasite development in the ticks. (+info)
Cutaneous manifestation of giardiasis - case report.
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Giardia intestinalis is a protozoan parasiting the gastrointestinal tract of vertebrate hosts widely distributed throughout the world. Patients with giardiasis are usually asymptomatic but the presence of the parasite may lead to a variety of clinical manifestations, including skin lesions. In this report we present a case of a 31-year-old female patient with skin lesions of granuloma annulare type confirmed by a skin biopsy, who was diagnosed with giardiasis. The clearance of the skin lesions after antiparasite treatment seems to support correlation between dermatological symptoms and infection with Giardia intestinalis . (+info)
Developing drugs for developing countries.
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Infectious and parasitic diseases create enormous health burdens, but because most of the people suffering from these diseases are poor, little is invested in developing treatments. We propose that developers of treatments for neglected diseases receive a "priority review voucher." The voucher could save an average of one year of U.S. Food and Drug Administration (FDA) review and be sold by the developer to the manufacturer of a blockbuster drug. In a well-functioning market, the voucher would speed access to highly valued treatments. Thus, the voucher could benefit consumers in both developing and developed countries at relatively low cost to the taxpayer. (+info)
Model-based analysis of trial data: microfilaria and worm-productivity loss after diethylcarbamazine-albendazole or ivermectin-albendazole combination therapy against Wuchereria bancrofti.
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OBJECTIVES: To determine the efficacies of combinations of ivermectin or diethylcarbamazine and albendazole, which are recommended for use in mass treatment programmes against lymphatic filariasis. METHOD: Review of published trends in microfilarial (mf) intensities after treatment with these combination therapies. By fitting a mathematical model of treatment effects to the trial data, we quantified the efficacy of treatment, distinguishing between the killing of mf (mf loss) and a reduction in mf production by adult worms (worm-productivity loss). After diethylcarbamazine-albendazole treatment mf density dropped immediately, then slowly but steadily decreased further (four trials). After ivermectin-albendazole treatment, mf densities immediately dropped to near-zero levels, followed by a small increase (five trials). For diethylcarbamazine-albendazole treatment the average mf loss was approximately 83% (ranging from 54% to 100% in the different studies) and worm-productivity loss was 100% (in all studies). For ivermectin-albendazole treatment, average mf loss was 100% (ranging from 98% to 100%) and worm productivity loss was 96% (ranging from 83% to 100%). The effects were dose-dependent. Sensitivity analysis showed that the estimates did not depend on assumptions on worm lifespan or premature period and little on assumptions on mf lifespan. CONCLUSION: The two therapies differ with respect to their direct effect on mf, but both are highly effective against adult worms. If mass treatment with these combination therapies achieves high coverage, they can have a large impact on lymphatic filariasis transmission. (+info)
In vitro leishmanicidal constituents of Millettia pendula.
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The in vitro leishmanicidal constituents of Millettia pendula were examined. Two new compounds, 1 (millettilone A) and 2 (millettilone B), were isolated from the methanol extract of M. pendula, together with six known compounds: 3R-claussequinone (3), pendulone (4), secundiflorol I (5), 3,8-dihydroxy-9-methoxypterocarpan (6), 3,10-dihydroxy-7,9-dimethoxypterocarpan (7), and formononetin (8). Among these, pendulone showed the most potent leishmanicidal activity. Compound 2 was found to be a purple pigment in this heartwood. Their chemical structures were elucidated using spectral methods. (+info)
Peptide antimicrobial agents.
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Antimicrobial host defense peptides are produced by all complex organisms as well as some microbes and have diverse and complex antimicrobial activities. Collectively these peptides demonstrate a broad range of antiviral and antibacterial activities and modes of action, and it is important to distinguish between direct microbicidal and indirect activities against such pathogens. The structural requirements of peptides for antiviral and antibacterial activities are evaluated in light of the diverse set of primary and secondary structures described for host defense peptides. Peptides with antifungal and antiparasitic activities are discussed in less detail, although the broad-spectrum activities of such peptides indicate that they are important host defense molecules. Knowledge regarding the relationship between peptide structure and function as well as their mechanism of action is being applied in the design of antimicrobial peptide variants as potential novel therapeutic agents. (+info)
Filaria-induced monocyte dysfunction and its reversal following treatment.
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Monocyte dysfunction in filarial infection has been proposed as one mechanism underlying the diminished antigen-specific T-cell response seen in patent lymphatic filariasis. Cytokine/chemokine production and gene expression in monocytes from filaria-infected patients and uninfected healthy donors were assessed unstimulated and in response to stimulation with Staphylococcus aureus Cowan I bacteria plus gamma interferon both before and 8 months following treatment. Monocytes from filaria-infected individuals were studded with intracellular microfilarial antigens. Furthermore, monocytes from these individuals were less capable of producing interleukin-8 (IL-8), Exodus II, MIP-1alpha, MIP-1beta, and IL-1alpha and preferentially expressed genes involved in apoptosis and adhesion compared with monocytes from uninfected donors. Eight months following treatment with a single dose of ivermectin-albendazole, some of these defects were reversed, with monocyte production of IL-8, IL-1alpha, MIP-1alpha, and IL-10 being comparable to that seen in the uninfected controls. In addition, a marked increase in mRNA expression of genes associated with protein metabolism, particularly heat shock proteins, was seen compared with pretreatment expression. These data suggest that the function and gene expression of monocytes in filaria-infected patients are altered but that this dysfunction is partially reversible following antifilarial treatment. (+info)
Role of ivermectin in the treatment of severe orbital myiasis due to Cochliomyia hominivorax.
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We describe 2 patients with severe orbital myiasis due to Cochliomyia hominivorax (of the order Diptera and the family Calliphoridae) who had underlying skin carcinomas and were treated with oral ivermectin and debridement. We suggest that ivermectin plays an important role in the treatment of severe cases of myiasis. (+info)