[The experimental pathogenic effect of Spiroplasma isolated from mosquitoes on the hatching of Aedes aegypti ova and the growth of larva hatched from these eggs]. / Etude de l'effet pathogène expérimental des spiroplasmes isolés à partir de moustiques sur l'éclosion d'oeufs d'Aedes aegypti et le devenir des larves issues de ces oeufs.

The authors did study the experimental effects on Aedes aegypti ova of different Spiroplasma strains, isolated from mosquitoes in French Savoy and in Taiwan. The SP7 strain, from Armigeres subalbatus (Taiwan), demonstrates a true pathogenic effect on the larval evolution, without sex ratio modifications, nor bacterial transmission to the adult mosquitoes. The authors present their results and emphasize the difficult use of Spiroplasmas sp.

Mosquito spiroplasmas from France and their ecology.

Spiroplasmas have been isolated previously from a number of blood-sucking arthropods, including ticks, horseflies, and deerflies. More recently, spiroplasmas were isolated from mosquitoes from the USA, France, and Taiwan. Spiroplasmas isolated from mosquitoes from France belong to at least three serogroups and are serologically different from one of the Taiwan isolates, Sp2. Our Ar 1343 strain is the prototype of a new serogroup (XIII). During 3 consecutive years (1983-85), the ecology of these spiroplasmas was studied in different biotopes near, and in, the Isère River Valley in Savoia, France. A total of 23 strains was isolated from four species or groups of mosquitoes (Aedes sticticus/vexans, Ae. cantans/annulipes, Ae. cinereus/geminus and Coquillettidia richiardii). Spiroplasmas were isolated only from female mosquitoes and only during June and July. An as yet unidentified virus was also isolated from three mosquito pools, one of which yielded spiroplasmas. Spiroplasma viruses were not detected. Antibody to our Ar 1357 isolate was found in 4 of 20 sera from cows living in the areas studied, but not in sera from wild rodents or in sera from rabbit or pigeon sentinels. Finally, preliminary results are presented on the effects of experimental infection of Ae. aegypti with the Ar 1357 isolated (serogroup XXII).

[Spiroplasmas and hematophagous arthropods; prospects in tropical pathology]. / Spiroplasmes et arthropodes hématophages; perspectives en pathologie tropicale.

Spiroplasmas are original wall-free prokaryotes which exhibit motility and a helical shape although lacking any cell wall or motile apparatus. They are known by phytopathologists because some of them are responsible for severe arthropod-borne plant diseases, such as Spiroplasma citri, the etiologic agent of "citrus stubborn disease". Other spiroplasmas are pathogenic for a number of insects: drosophila, bees and beetles. More recently spiroplasmas were also isolated from ticks, mosquitoes, horse-flies and deer-flies opening a new chapter in medical pathology. These agents are of possible great significance in Tropical Medicine.

[Isolation of Spiroplasma in France (Savoie, North Alps) from mosquitoes of Aedes genus]. / Isolement de Spiroplasmes en France (Savoie, Alpes du Nord) à partir de moustiques du genre Aedes.

Six strains of Spiroplasma sp. were isolated from Aedes mosquitoes collected in France, in the northern part of the Alps. As these isolates came from anthropophilic species of mosquitoes, the possible epidemiological and pathological importance of such observations is briefly discussed. No virus was isolated from these same mosquitoes.