J. Whitworth

Bio: J. Whitworth is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 125 citations.

Re-assessing the global prevalence and distribution of lymphatic filariasis.

Abstract: This paper estimates the global burden of lymphatic filariasis based on a review of the published literature on infection and disease surveys. A method for aggregating and projecting prevalence data from individual studies to national, regional and global levels, which also facilitates the estimation of gender and age-specific burdens, is presented. The method weights in favour of the larger, and hence presumbably more reliable, studies and relies on estimated empirical relationships between gender, age, infection and disease in order to correct studies with incomplete data. The results presented here suggest that although the overall prevalence of filariasis cases is 2.0% globally (approximately totalling 119 million cases), the disease continues to be of considerable local importance, particularly in India and Sub-Saharan Africa. Estimates by age and gender clearly show that, unlike other helminth infections, filariasis is mainly a disease of the adult and older age-classes and appears to be more prevalent in males. This work suggests that the derivation of more accurate estimates of the burden of filariasis will require a better understanding of both the epidemiology and the spatial aspects of infection and disease. It also suggests that filariasis is preventable based on a geographically targeted strategy for control.

How much human helminthiasis is there in the world

Abstract: The impact of Norman Stoll's presidential address to the American Society of Parasitologists in Boston at Christmas time in 1946 has been and continues to be immense. Since its publication in 1947, have any helminthologists not read it? Have any parasitology text books not cited it since then? Does any parasitology course today not refer students to it? Despite our expanding knowledge of DNA, molecular biology, and immunology and the application of mathematical techniques to our understanding of epidemiology and helminth population biology, Stoll's appraisal of the wormy world still excites and challenges our imaginations. A measure of the influence of Stoll's paper is the fact that we regularly use the title of "This Wormy World" as we seek to draw attention to the global public health significance of human helminth infections. CRC Press reprinted the paper (renamed as "The Wormy World") and supplied a commentary in each of a series of volumes dealing with zoonoses (CRC, 1982). The World Health Organization used the same title for an issue of its official magazine (WHO, 1984) and recently Parasitology Today devoted an issue to revisiting the subject of "This Wormy World" in which Bundy (1997a) explained why Stoll's paper has been supremely important in directing our approach to the study and management of human helminth infections and colleagues evaluated the current status of several major helminthiases. Only last year, Bundy and de Silva (1998) again wrote about this wormy world, this time with themes of optimism and encouragement over prospects for control. In this article, I have sought to place Stoll's evaluation of human helminthiasis in a contemporary setting. I have tried to address some of the questions he asked and to review aspects of current progress in the control of human helminthiasis. Most of all, I hope this paper will be seen as a tribute to Stoll's inspirational leadership and will serve as a reminder of our need to tackle what he saw as an "unremittingly corrosive" burden of disease.

Synthesis of silver nanoparticles using Nelumbo nucifera leaf extract and its larvicidal activity against malaria and filariasis vectors.

Abstract: The aim of this study was to investigate the larvicidal potential of the hexane, chloroform, ethyl acetate, acetone, methanol, and aqueous leaf extracts of Nelumbo nucifera Gaertn. (Nymphaeaceae) and synthesized silver nanoparticles using aqueous leaf extract against fourth instar larvae of Anopheles subpictus Grassi and Culex quinquefasciatus Say (Diptera: Culicidae). Nanoparticles are being used in many commercial applications. It was found that aqueous silver ions can be reduced by aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. The results recorded from UV–vis spectrum, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared support the biosynthesis and characterization of silver nanoparticles. Larvae were exposed to varying concentrations of plant extracts and synthesized silver nanoparticles for 24 h. All extracts showed moderate larvicidal effects; however, the maximum efficacy was observed in crude methanol, aqueous, and synthesized silver nanoparticles against the larvae of A. subpictus (LC50 = 8.89, 11.82, and 0.69 ppm; LC90 = 28.65, 36.06, and 2.15 ppm) and against the larvae of C. quinquefasciatus (LC50 = 9.51, 13.65, and 1.10 ppm; LC90 = 28.13, 35.83, and 3.59 ppm), respectively. These results suggest that the leaf methanol, aqueous extracts of N. nucifera, and green synthesis of silver nanoparticles have the potential to be used as an ideal eco-friendly approach for the control of the A. subpictus and C. quinquefasciatus. This is the first report on the mosquito larvicidal activity of the plant extracts and synthesized nanoparticles.

The Major Surface Protein of Wolbachia Endosymbionts in Filarial Nematodes Elicits Immune Responses through TLR2 and TLR4

Abstract: More than 150 million humans in tropical countries are infected by filarial nematodes which harbor intracellular bacterial endosymbionts of the genus Wolbachia (Rickettsiales). These bacteria have been implicated in adverse effects of drug treatment in filariasis. The present study provides evidence that purified major Wolbachia surface protein (rWSP) acts as an inducer of the innate immune system through TLR2 and TLR4: 1) recombinant, stringently purified rWSP elicited the release of TNF-alpha, IL-12, and IL-8 from cultured blood cells of both Onchocerca volvulus-infected and uninfected people; 2) the inflammatory response to rWSP challenge was TLR2- and TLR4-dependent as demonstrated with TLR-transfected fibroblastoid cells, as well as macrophages and dendritic cells from functional TLR-deficient mice; 3) blood cells of onchocerciasis patients exposed to rWSP also generated down-regulating mediators IL-10 and PGE(2) after 6 days of culture; 4) furthermore, rWSP-reactive IgG1 Abs were present in sera of O. volvulus-infected people but not in those of uninfected Europeans. The lack of rWSP-reactive IgE and IgG4 in serum indicated a bias toward a Th1-type adaptive immune response. Abs against rWSP stained endobacteria in living and degenerating adult O. volvulus filariae, tissue microfilariae and host tissue macrophages that apparently had engulfed microfilariae. Thus, filarial helminths, through products of their endobacteria such as WSP, acquire characteristics of a typical microbial pathogen inducing immune responses via TLR2 and TLR4.