Pathogen- and Host-Directed Antileishmanial Effects Mediated by Polyhexanide (PHMB)

BACKGROUND:Cutaneous leishmaniasis (CL) is a neglected tropical disease caused by protozoan parasites of the genus Leishmania. CL causes enormous suffering in many countries worldwide. There is no licensed vaccine against CL, and the chemotherapy options show limited efficacy and high toxicity. Localization of the parasites inside host cells is a barrier to most standard chemo- and immune-based interventions. Hence, novel drugs, which are safe, effective and readily accessible to third-world countries and/or drug delivery technologies for effective CL treatments are desperately needed. METHODOLOGY/PRINCIPAL FINDINGS:Here we evaluated the antileishmanial properties and delivery potential of polyhexamethylene biguanide (PHMB; polyhexanide), a widely used antimicrobial and wound antiseptic, in the Leishmania model. PHMB showed an inherent antileishmanial activity at submicromolar concentrations. Our data revealed that PHMB kills Leishmania major (L. major) via a dual mechanism involving disruption of membrane integrity and selective chromosome condensation and damage. PHMB's DNA binding and host cell entry properties were further exploited to improve the delivery and immunomodulatory activities of unmethylated cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODN). PHMB spontaneously bound CpG ODN, forming stable nanopolyplexes that enhanced uptake of CpG ODN, potentiated antimicrobial killing and reduced host cell toxicity of PHMB. CONCLUSIONS:Given its low cost and long history of safe topical use, PHMB holds promise as a drug for CL therapy and delivery vehicle for nucleic acid immunomodulators

Temporal abundance of Aedes aegypti in Manaus, Brazil, measured by two trap types for adult mosquitoes

A longitudinal study was conducted in Manaus, Brazil, to monitor changes of adult Aedes aegypti (L.) abundance. The objectives were to compare mosquito collections of two trap types, to characterise temporal changes of the mosquito population, to investigate the influence of meteorological variables on mosquito collections and to analyse the association between mosquito collections and dengue incidence. Mosquito monitoring was performed fortnightly using MosquiTRAPs (MQT) and BG-Sentinel (BGS) traps between December 2008-June 2010. The two traps revealed opposing temporal infestation patterns, with highest mosquito collections of MQTs during the dry season and highest collections of BGS during the rainy seasons. Several meteorological variables were significant predictors of mosquito collections in the BGS. The best predictor was the relative humidity, lagged two weeks (in a positive relationship). For MQT, only the number of rainy days in the previous week was significant (in a negative relationship). The correlation between monthly dengue incidence and mosquito abundance in BGS and MQT was moderately positive and negative, respectively. Catches of BGS traps reflected better the dynamic of dengue incidence. The findings help to understand the effects of meteorological variables on mosquito infestation indices of two different traps for adult dengue vectors in Manaus

Two new species of Myxobolus (Myxozoa:Myxosporea:Bivalvulida) from freshwater fishes of Punjab wetlands (India)

During the present study two new species were collected from mucous membrane around gill lamellae of Puntius sophore (Ham.) vern. chittal and Cirrhina mrigala (Ham.) vern. mrigal from Harike Wetland, Punjab respectively. Spore of the first species i.e. Myxobolus chittalii are histozoic, pear shaped with characteristic nipple-like anterior end and rounded posterior end. They measure 9.0 × 6.18 μm. Polar capsules are two, equal, measuring 4.5 × 2.4 μm, pyriform with bluntly pointed anterior end and rounded posterior end. They are placed posteriorly from the tip of the spore and are parallel to each other in the spore body cavity. A prominent, tongue shaped intercapsular process is present. Spores of the second species i.e. M. mehlhorni are histozoic, oval to egg in shape having narrow, blunt anterior end and broad rounded posterior end, measure 8.9 × 6.8 μm. Shell valves smooth, symmetrically thin, measure 0.5 μm in thickness. Parietal folds are absent. Polar capsules two, prominently unequal, placed anteriorly and converge towards the anterior end. Both polar capsules are flask-shaped with anterior end having a prominent neck. The larger polar capsule measure 3.7 × 2.5 μm occupying less than half while the smaller one measure 2.6 × 1.5 μm and occupy less than one-third of the spore body cavity. An intercapsular process is absent

A new myxosporean species Myxobolus sclerii sp. nov. and one known species M. stomum Ali et al. 2003 from two Indian major carp fishes

The present communication deals with description of one new species of Myxobolus (Myxozoa: Myxosporea: Bivalvulida), M. sclerii sp. nov. infecting eye ball of Catla catla (Hamilton) and redescription of M. stomum infecting scales of Labeo rohita (Hamilton), two major carps of Kanjali and Ropar Wetlands respectively. Spores of M. sclerii sp. nov. measure 7.9–9.5(8.7 ± 1.13) × 4.3–5.7(5 ± 0.98) μm in size. Parietal folds absent. Polar capsules two, equal and measuring 4–5.4(4.7 ± 0.98) × 1–2.6(1.8 ± 1.31) μm in size. A rod-shaped medium-sized intercapsular process is present. Iodinophilous vacuole present measuring 2.19–4.13(3.16 ± 1.37) μm in diameter. Spores of M. stomum Ali et al.2003 measure 9.8–10.3(10.0 ± 0.35) × 7.9–8.7(8.3 ± 0.56) μm in size, with rounded anterior and posterior end. Spore valves smooth, symmetrical, thick measuring 0.88 μm in thickness. Parietal folds absent. Two anteriorly situated polar capsules are equal, pear-shaped measuring 4.8–5.2(5.0 ± 0.28) × 1.5–2.3(1.9 ± 0.56) μm in size, each with a neck leading to a fine duct opening independently. Both polar capsules converge slightly anteriorly but diverge apart posteriorly occupying more than half of spore body. Intercapsular appendix is absent. Earlier, the parasite was recorded in the buccal cavity, muscles and lips of Plectorhynchus gaterinus (Forsskal), Egypt. A new locality-Ropar Wetland, a new location-scales and a new host- Labeo rohita (Hamilton) are recorded for this parasite