[
Parasitol Today,
2000]
Lymphatic filariasis caused by Wuchereria bancrofti and Brugia malayi is endemic throughout most of the southern half of the Philippine archipelago. Economic and manpower shortages prior to 1996 made it difficult to acquire new prevalence data and vector control data concurrently from all provinces. Nevertheless, analysis of cumulative prevalence data on filariasis indicates the persistence of filariasis in each of the three major island groups - Luzon, Visayas and Mindanao - including 45 out of 77 provinces. Here, Michael Kron and colleagues summarize the prevalence data, and review host, parasite and vector characteristics relevant to the design and implementation of disease control initiatives in the Philippines planned for the year 2000.
[
1980]
The use of nematodes as model organisms for the study of metazoan organization assumes a detailed knowledge of all facets of their biology. This chapter covers the nutritional aspects of the nematode model as revealed by studies on Caenorhabditis briggsae and Caenorhabditis elegans and a few other nematode species that have been established in axenic culture. The term axenic, which means "free of other organisms" was proposed by Dougherty (1960) in preference to other terms such as "sterile", "aseptic", and "pure" that would be rather ambiguous in this respect. Since most of the nematodes under discussion are bacteria feeders and some of them fungal-feeding species, it is essential that axenic culture conditions are rigidly maintained when studying nematode requirements. This chapter appraises the present state of nematode nutrition, and refers particularly to those nematodes that are currently used as model organisms for basic research of behavior, development, and aging. Detailed information on the culture methods and specific diets of these and other nematodes in axenic culture may be found in a previous review.
[
Annual Review of Phytopathology,
1978]
Two excellent reviews, one of them recent, are available on the axenic culture of nematodes. Therefore, the present article is mainly an outline of the present state of nematode culture research and is limited to surveying reports that have a significant bearing on our understanding of nematode growth in axenic culture. The first section covers nutritional requirements with special attention to the material needed for growth and reproduction in repeated subculture. Since nematode nutrition has largely been studied on the free-living nematode Caenorhabditis briggsae, I first scrutinize the dietary requirements of this species and extend our knowledge to other nematodes in axenic culture thereafter. In particular, I demonstrate how a general understanding of the nature of the growth factor emerges from a discriminatory analysis of existing knowledge and I support this concept with experimental evidence; also I attempt to reconcile this concept with some older as well as more recent controversial findings. The next section is devoted to culture methodology and covers some new techniques that render nematodes convenient as model organisms for scientific research. Throughout this review I use the terminology proposed by Dougherty for describing culture conditions with respect to the number of coexisting species and the different degrees of chemical differentiation of the media. The term axenic means free of contaminating organisms and supersedes the less suitable adjectives sterile or aseptic. Monoxenic cultures contain one additional species or tissue (e.g. alfalfa callus tissue), dixenic two and so on. Species that are studied in xenic cultures are reared in interaction with several unidentified organisms. Media that are chemically undefined are called oligidic. Those consisting of a defined basal portion and a less defined supplement are meridic. Holidic media are fully defined and contain