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Drosophila C virus: experimental study of infectious yields and underlying pathology in Drosophila melanogaster
E Gomariz-Zilber1, M Poras, M Thomas-Orillard
1Bât. C, 2ème étage, Université Pierre et Marie Curie, Paris, France.
Abstract:
The underlying pathology of a nonhereditary virus, the Drosophila C virus, was studied. This study was related to the contamination routes (ingestion or contact) and developmental timing. When oral contamination occurred at the first larval instar: (1) the flies were contaminated, (2) the flies which had developed the most rapidly were the most infected, (3) in newly emerged females, the level of virus was higher than in newly emerged males, (4) when infected flies were reared on virus-free medium only males lost their virus. Moreover, oral contamination of adults was very efficient, but the highest virus yield was obtained when both larvae and imagos grew on virus-contaminated medium. About 30 to 50% of the flies died on the sixth day. They were as DCVC invaded as DCVC-injected flies. It seemed that when the virus yield was higher than a given threshold, all flies died, whatever had been the contamination routes. When contaminated adult females and virus-free males were reared together on a virus-free medium, females could infect males. In contrast, contaminated males were not able to infect virus-free females. Thus, only females were able to contaminate a rearing medium or other flies.
Insights
Drosophila C virus infection depends on developmental stage and contamination route. Rapidly developing larvae and adult females are more susceptible, with females transmitting the virus effectively.
Area of Science:
- Virology
- Entomology
- Insect Pathology
Background:
- The Drosophila C virus (DCV) is a nonhereditary pathogen affecting fruit flies.
- Understanding DCV transmission routes and pathology is crucial for insect population management.
Purpose of the Study:
- To investigate the pathology of Drosophila C virus.
- To determine the influence of contamination routes and developmental timing on DCV infection.
- To identify factors affecting virus transmission within fly populations.
Main Methods:
- Oral contamination of Drosophila melanogaster larvae and adults at different developmental stages.
- Monitoring infection levels and mortality rates.
- Assessing virus transmission between sexes and to the rearing medium.
Main Results:
- Oral contamination at the first larval instar led to infection, with faster-developing flies showing higher infection rates.
- Newly emerged females had higher virus levels than males; only males lost the virus when moved to a virus-free medium.
- Adult oral contamination was efficient, but highest virus yield occurred when both larvae and adults were exposed.
- A high virus yield, regardless of contamination route, resulted in 30-50% mortality by day six.
- Contaminated females could infect males, but not vice versa, indicating females are the primary transmitters.
Conclusions:
- Drosophila C virus infection dynamics are significantly influenced by the host's developmental stage and exposure route.
- Females play a critical role in the transmission of Drosophila C virus within a population and to the environment.
- High viral loads are lethal, irrespective of the initial contamination pathway.