The purpose of this workshop was to collect together colleagues investigating the intermediary metabolism of protozoa, with a view to discussing those pathways involved in energy metabolism and the production of ATP and other high-energy compounds, together with the factors affecting energy balance. The aspects of energy metabolism chosen for discussion comprised the metabolic pathways ranging from the strictly anaerobic to highly oxidative; subcellular compartmentation of these pathways within the protozoa; the functional role of these pathways including a consideration of aero-tolerance; and the use of inhibitors as biochemical probes and potential chemotherapeuticagents. Hopefully this approach has produced a broad 'over-view' of important areas of protozoan energy metabolism which will enable both the specialist and non-specialist to appreciate the similarities and differences between the metabolic behaviour of a range of protozoa.

Even if we do not always acknowledge the fact, nutrition is a fundamental aspect of symbiosis and parasitism. (1) The significance of nutrition often forms a basic feature in schemos of classification of the various associations between living organisms (see Read, 1908; Whitfield, 1979). (2) The growth and reproduction of different parasites appear to Vary in response to the nutrition of the host (see Mettrick & Podesta, 1974; Nesheim, Crompton, Arnold & Barnard, 1977; 1978; Parshad, Crompton & Nesheim, 1980). (3) The course of a parasitic infection may also vary in response to the nutritional status of the host and perhaps such variations are the result of the affocts of nutrition on the host's immune response (Chandra & Nowberne, 1977; Chandra, 1980). (4) Finally, parasitic disease is well known to be much more scrious in undernourished hosts (see Chandra & Newberne, 1977); when man's the deprived host, the impact of infections and parasitic disease on young children is Particularly severe and distressing (Latliam, 1975).

Although methods for quantitative immunoassay have been available for a long time and have been used as a diagnostic tool for viral and bacterial diseases, as well as for immunological disorders, it is only recently that such methods have found wider application in parasitology. There are probably several reasons for this. One is that in developed countries parasitic diseases and in particular tropical infections were for a long time not recognized as severe health problems which deserved serious attention. Many technical problems have also been associated with parasite serology. Earlier serological methods were, for various reasons, unsuitable for use in the diagnosis of parasitic infections. For instance, the complement fixation test is, in many instances, not sensitive enough to detect active infection and the later introduced passive haemagglutination test, which has a considerably higher level of sensitivity, has the disadvantage of not detecting antibodies to carbohydrate antigens, such as some of the diagnostic antigens of adult schistosomes.

The oncomiracidia larvae of monogeneans are small, ciliated, relatively slow-moving organisms with a limited free-swimming life. For example, the oncomiracidium of the skin parasite Entobdello, soleae is 250 µm in length, swims at a speed of 5 mm/sec and lives for about 24 h (Kearn, 1967a). Oncomiracidial survival is dependent on the larvae finding and attaching themselves to their specific fish hosts and selection pressure has been exerted on the timing of hatching of oncomiracidia and on their behaviour during their short freeswimming lives to enhance the chances of making this important contact.

Insecticide resistance is a serious problem in the control of many vector-borne diseases, particularly in developing countries where the possibility of changing to an alternative compound may be restricted. Consequently genes giving susceptibility to insecticides in vector species can be viewed as constituting a valuable resource to be used up with discretion. The exchange of information and thought taking place in the Workshop was centred upon possible ways to conserve this resource, i.e. to slow down the evolution of resistance while maintaining adequate control, so preserving the effective life of available insecticides as long as possible. The subject was treated mainly in relation to insect vectors of disease although niost of the discussion would also be relevant to other insect pests.

The kinetoplast DNA (kDNA) of kinetoplastidae was the first mitochondrial DNA (mtDNA) to be discovered, and with its unusual network structure, consisting of more than 104 catenated DNA circles, it is without equal in nature. Analysis of networks from various genera (reviewed by Borst & Hoeijmakers (1979a) and Englund (1980)) has shown that they always consist of two components: mini-circles and maxi-circles (see Table 1). The mini-circles are the major component and deterraine the size and sliape of networks. They vary in size between 1 and 3 kilo-base pairs (kb = 1000 base pairs (bp)), they are heterogeneous in sequence, their sequence evolves rapidly and their function is not yet known. The maxi-circles, on the other hand, are homogeneous in sequence, their sequence is conserved and they probably represent the counterpart of mtDNA in other organisms.

In vector-borne diseases it is generally the vector which determines the success of disease transmission and efforts to limit the incidence of such diseases generally involve control of the vector. The very nature of their feeding habits renders haematophagous arthropods prime candidates for disease transmission and a great deal is now known of the biology of the most important vectors. Nevertheless, there are many areas in which our knowledge is incomplete or about which conflieting views exist.

Modern chemical insecticides revolutionized the fight against vector-borne diseases during the period following the Second World War. They are extensively used at present for that purpose and will very likely continue to play an important role in the foreseeable future. However, these insecticides have their limitations.

During the early period of the study of microsporidia (now phylum Microspora) simple morphological features, in particular the number of spores produced by each sporoblast, were used to define genera. This led to the assemblage in genera of parasites, which when their developmental characters and host/parasite relationships were examined, could not be considered to be closely related. The Workshop was convened in Order to discuss the relative value of characters used for defining genera and to investigate selected problems of generic segregation and aggregation in representative classes. It was hoped to expose some of the inadequacies in the present methods and make recommendations for generic definitions which would form the basis of a taxonomic System, itself reflecting the phylogeny of the group.

The ecology of Leishmania of man is concerned with the circulation of the parasite in nature from one mammal to another by the bite of phlebotomine sandflies. The natural vertebrate hosts are anthropocentrieally referred to as reservoir hosts although in sorac foci of human leishmaniasis (anthroponotic cutaneous leishmaniasis and Indian kala-azar) man himself is thought to be the reservoir.

Two tapeworms, Taenia saginata and Echinococcus granulosus, cause serious economic and human health problems in several parts of the world. Some of these Problems might be solved if a cheap, easy and safe vaccination could be developed. Before a vaccination against adult tapeworms can be developed it is necessary to know how intestinal tapeworm populations are controlled by immune mechanisms. For this purpose laboratory modeis have been used involving mainly species of Hymenolepis in rodents and especially H. diminuta in mice and rats, which will be referred to below.

There are few, if any, authenticated records of fossil helminths or even of the hard parts of ectoparasitic monogeneans. This means that theories of helminth evolution can be based only on indirect evidence and are unlikely to be confirmed or refuted by palaeontologists.

Currently three main areas of study provide evidence of evolutionary trends: (i) morphology, in its broadest sense; (ii) life-history studies; (iii) host spectra and geographical distribution.

The genus Ostertagia, created on the basis of the presence of an accessory bursal membrane by Ransom (1907) and later placed in the family Trichostrongylidae Leiper, 1912, did not require reorganization until its revision by Orloff (1933). Although other related genera were described around this time the systematics of the whole group remained workable.

In 1979 the French population included 4200000 foreigners. While many came from European countries, mainly Spain, Portugal and Italy, a considerablc percentage came from the warmer belts of the earth: 20 % Algerians, 8 % Moroccans, 4 % Tunisians, 2 % black Africans. The total number has been on the decrease since 1978. However, metropolitan France has recently received, for political reasons, large groups from the Near East (Lebanese) and Southeast Asia (up to now 100000 Cambodians, Laotians and Vietnamese).

I feel greatly honoured to have been asked to speak to you about Alphonse Laveran. Professor Garnham wondered if I had met Laveran and what was the State of his relations with Professor Emile Brumpt my father. I have known many Pastorians: Emile Roux, Mesnil, Marchoux, Roubaud, Charles Nicolle, but unfortunately not Laveran.