ISSN:
1432-1955
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Progress in the understanding of the sporozoa stemmed from new concepts and new measurements, often using refined techniques. New concepts developed from linking knowledge about the cyst-related transmission of Toxoplasma to oocyst-related transmission of the coccidia. It is now apparent that both oocyst and tissue cyst transmission occur in Toxoplasma, Sarcocystis, Hammondia n.g., Isospora and perhaps Atoxoplasma. It is likely that we know the complete cycles of Toxoplasma and Sarcocystis and some progress has been made towards understanding those of Besnoitia and Frenkelia. Our present knowledge is sufficient to propose a new classification of some of the higher coccidia (Table 5), and to devise keys for the determination of cysts and oocysts (Tables 2, 4). Additional terminology is listed (Table 1). Refined measurements have advanced our knowledge of the ultrastructure, biology and transmission of Toxoplasma and Sarcocystis and related organisms, of Hepatozoon, Plasmodium, Parahaemoproteus, Simondia and Leucocytozoon. New techniques have been used for study of DNA and isoenzymes, chromosome polymorphism, and the endocrine-photoperiodic relationships of Plasmodium. Future progress will occur predictably in the areas of finer measurements and new techniques. Unpredictable are conceptual advances, both inductive and deductive. Inductive concepts derive from phylogenetic considerations and from life cycle patterns, although they may really be overgeneralizations; or, from a classification, although unfortunately the stress on pattern may neglect evidence of diversity. Deductive conceptual advances come from new observations, often serendipitously derived, which sometimes have a cascade effect. While they cannot be planned, deductive conceptual advances from observations can be encouraged, since hard work and careful study will make them happen more frequently.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00348532
