A. Chabaud

Les Nématodes Trichostrongylina parasites d'Amphibiens et de Reptiles: problèmes taxonomiques, phylétiques et biogéographiques

Except for four species of the Mertensinematinae (Molineoidea) not considered in this work, the Trichostrongylina parasitic in amphibians and reptiles, comprising 15 genera and 105 species, are reviewed. The morphological characteristics of each species are analysed. The most important characteristics are provided by the disposition of the caudal bursal rays, the morphology of the synlophe (at the oesophago-intestinal junction and mid-body level) and by the anatomy of the spicules. The species are classified into seven groups:Group 1: “relict” species with six lips and well-developed buccal capsule (six genera and 16 species).Group 2: “ancient” species with one or two primitive characters (eight genera and 15 species).Seventy-four species, without primitive characters, comprise the genus Oswaldocruzia which is subdivided into five groups.Group 3: Oriento-Ethiopian species with non-“idiomorphic” spicules with two to three tips (10 species).Group 4: Neo-Ethiopian species with non-“idiomorphic” spicules with numerous tips (11 species).Group 5: Holarctic species with “idiomorphic” spicules with the spicular fork divided above the distal third of the spicule length (24 species).Group 6: Continental Neotropical species with “idiomorphic” spicules and spicular fork divided within the distal third of the spicule length (21 species).Group 7: Caribbean Neotropical species with modified “idiomorphic” spicules, the three main branches of which are each divided into numerous tips (eight species).The geographical distribution of the species appears to be of greater significance than the host spectrum and suggests the following biogeographical hypotheses: Group 1, entirely Gondwanan, diversified during the Cretaceous era prior to the separation of the southern continents. The expansion of Group 2, which is represented by Gondwanan and Oriental species mainly from India, Malaysia and Indochina, could have occurred throughout South-East Asia at the end of the Cretaceous era when India collided with Eurasia. Group 3 could be interpreted either as a migration from Asia to Africa during the upper Eocene, or more likely during the Miocene, or, by a dispersion due to the migrations of Bufo melanostictus. Group 4 may result from the expansion of the former group in the Ethiopian region. Group 5 could be interpreted as a colonisation of western Europe and the Nearctic from Asia during the Tertiary. Group 6 could have arisen after the migration of the Neartic species to the Neotropical region during the Pliocene period and Group 7 by the expansion of the former group in the Caribbean.Amongst the Trichostrongylina, the “relict” and “ancient” genera parasitic in amphibians and reptiles can only be compared with the genera parasitic in birds and mammals, probably dating from the Palaeocene period (mainly marsupials and primitive insectivores). On the other hand, the genus Oswaldocruzia can be compared with other members of the Molineoidea parasitic in fissipeds, Pholidota and Chiroptera dating from a later period (Eocene) (see Durette-Desset, 1971). Thus, the Trichostrongylina of amphibians and reptiles are distinguished by the persistence of very old species, the evolution and the geographical distribution of which was arrested for millions of years, and by the existence (in some regions) of groups undergoing full evolutionary expansion.The new taxa proposed in the paper are: Bakeria (Moravec & Sey, 1986) status emend. (= Bakeria Moravec & Sey sub. g.), Ragenema n. g., Ragenema robustum (Baker, 1982) n. comb. (= Oswaldocruzia robusta), Typhlopsia quentini (Durette-Desset, 1980) n. comb. (= Trichoskrjabinia quentini), T. secundus (Pinnell & Schmidt, 1977) n. comb. (= Trichoskrjabinia secundus), T. gansi (Crusz & Ching, 1975) n. comb. (= Oswaldocruzia gansi), T. limnodynastes (Johnston & Simpson, 1942) n. comb. (= Oswaldocruzia limnodynastes), T. legendrei (Chabaud & Brygoo, 1962) n. comb. (= Oswaldocruzia legendrei).

Plasmodium vinckei petteri : identification of the stages sensitive to arteether

Antimalarial activity of arteether, a derivative of artemisinin (qinghaosu) against blood-induced infections of the highly synchronous Plasmodium vinckei petteri rodent species of malaria was evaluated in Swiss mice. A single subcurative dose of arteether of 2.2 mg/kg body weight was injected subcutaneously to mice, either during the prepatent period or during the patent infection, when different stages of the parasitic cycle were present in the blood. It was shown that rings and young trophozoites were the most susceptible stages to arteether. The drug had no effect on merozoites and little effect on mid-term trophozoites which is the stage most sensitive to chloroquine. The alcoholic solution (10% alcohol in sterile water) had an immediate effect while the oily solution (miglyol 840) was active between 3 and 21 hr after injection.

Strongylida nomenclature for taxa above the family group

It is necessary to distinguish the three main evolutionary lines which presently constitute the Trichostrongyloidea.We propose to raise the following taxa of Strongylida as presented in the CIH keys (1974). Ancylostomatina for Diaphanocephaloidea and Ancylostomatoidea. Strongylina for Strongyloidea. Trichostrongylina for Trichostrongyloidea. Metastrongylina for Metastrongyloidea.The Trichostrongylina suborder includes three superfamilies : Trichostrongyloidea, Molineoidea superfam. nov. and Heligmosomoidea superfam. nov.

Chronotherapy of malaria: An approach to malaria chemotherapy

Chronotherapy is the science of the timing of drug application so as to achieve optimal therapeutic success for the treatment of disease. Here, Irene Landau, Alain Chabaud, Gilles Cambie and Hagai Ginsburg show how a suitable animal model can be chosen, how the stage of parasite development most susceptible to the drug can be identified, and how this can eventually be used for the improvement of drug treatment.

The haemosporidian parasites of bats with description of Sprattiella alecto gen. nov., sp. nov.

Four species of Haemoproteidae were found in Pteropus alecto Temminck, 1837 in Queensland, Australia: i) Johnsprentia copemani, Landau et al., 2012; ii) Sprattiella alecto gen. nov., sp. nov., characterised by schizonts in the renal vessels; iii) Hepatocystis levinei, Landau et al., 1985, originally described from Pteropus poliocephalus Temminck, 1825 and, experimentally from Culicoides nubeculosus and found in this new host and for which features of the hepatic schizonts are reported; iv) gametocytes of Hepatocystis sp. which are illustrated but cannot be assigned to a known species. A tentative interpretation of phylogenetic characters of haemosporidians of bats is provided from the morphology of the gametocytes and localisation of the tissue stages with respect to recent data on the phylogeny of bats.

Stephanofilaria thelazioides n. sp. (Nematoda: Filariidae) from a hippopotamus and its affinities with the species parasitic in the African black rhinoceros

Stephanofilaria thelazioides n. sp. (Filarioidea: Filariidae: Stephanofilariinae) is described from a hippopotamus Hippopotamus amphibius. This nematode is close to S. dinniki Round, 1964, a parasite of the black rhinoceros Diceros bicornis in Africa, but differs from it in the number of cuticular spines surrounding the mouth, the arrangement of the cloacal papillae and the measurements of the spicules, gubernaculum and microfilariae. Species of the genus Stephanofilaria possess spines on the head which have been derived by modification of the sensory papillae. S. thelazioides is the most primitive species of the genus and has the least modified arrangement of these papillae, with six bifid internal labial spines, four bifid external labial spines and four cephalic papillae. The genus appears to have diversified in various mammals which have in common a thick skin, such as rhinoceroses, elephants, buffaloes and now the hippopotamus. It appears to have become adapted secondarily to domestic bovines, initially in Asia and subsequently in North America.

Modifications in the rhythm of schizogony in Plasmodium chabaudi chabaudi associated with the selection of chloroquine resistance

Abstract A high level of drug resistance was obtained with a line of Plasmodiumchabaudi maintained under intense chloroquine selection pressure according to the protocols established for P. berghei. The main objective of this work was to verify if the characteristic asynchronous schizogonic rhythm of naturally resistant rodent malaria parasites was also found when the drug resistance was induced experimentally. The degree of resistance was evaluated through the use of the “2% delay test” (DT) and the schizogonic rhythm, by reference to the synchronicity index (SI). The strain had originally a DT of 4.26 and an SI of 0.52. Following the application of 80 mg/kg chloroquine at each passage, as early as at the 8th passage the parasites rapidly became resistant and asynchronous. At the 17th passage the DT was 3.32 and the SI, 0.20. In the drug-resistant line the original indices, both the DT and the SI, were restored after deep-freezing, sporogony, or passage through a Percoll gradient, or simply by repeated intravenous subinoculations of blood. The clear correlation between asynchronicity and drug resistance is easily explained by the action of chloroquine, which favours the schizogonic cycles initiated by latent merozoites.

Laurostrongylus hoineffae n. gen., n. sp., a relict trichostrongylid from an endemic madagascan rodent

A new nematode, the type of a new genus and a new species Laurostrongylus hoineffae, parasitic in the cricetid rodent Gymnuromys roberti in Madagascar, is described. The species belongs to the Graphiidinae subfamily of Trichostrongylidae but some features point to its affinity to certain Libyostrongylinae, especially to two monospecific genera endemic in Madagascar Pararhabdonema and Cnizostrongylus. This ensemble of relict species seems thus to support the concept of a common ancestor for the Libyostrongylinae and Graphidiinae. The two subfamilies were supposed to originate in the Ethipian region. The presence of the three generain Madagascar could either indicate their Madagascan origin or, more likely, a continental origin with an insular niche allowing the preservation of the species.