Acknowledgements. Ranaviruses and Amphibians: outside the box of host-parasite relationships. 7/16/2011. Students Valérie St-Amour Pierre Echaubard

Transcription

1 Rnviruses nd Amphiins: outside the ox of host-prsite reltionships. Dr. Dvid Lesrrères Acknowledgements Students Vlérie St-Amour Pierre Echurd Collortors Dr. Roert Dr. Chinchr Dr Grner Dr. Grner Bruce Puli 1

2 From smll virus to ig prolem! Condition-dependent expression of rnvirl infection nd life history trde-offs Life-history stge susceptiility Genotype x Genotype x Environment interctions Perspectives nd future work Glol Distriution of Rnvirus Die-offs Courtesy of Hislip N. 11 Fmilies: Rnide, Hylide, Bufonide, Leptodctylide, Dendrotide, Discoglosside, Rhcophoride, Myotrchide, Amystomtide, Slmndride, Hynoiide 2

3 Condition-dependence of Rv expression -Pthogens hve importnt effects on host life-history trits. -Mgnitude of these effects is often strongly context-dependent. -Outcome of n interction etween host nd n infectious gent is often ssocited with the level of stress experienced y the host P H Density Contct rte High density High virulence High Density Tnks (40 tdpoles) Low Density Tnks (20 tdpoles) Dose Dose Dose Control C C C C C C Rnvirus virulence is density-dependent Dose increse /decrese fitness X High density, effect on fitness dispper 3

4 Beneficil infection? Host non-infected Host fitness Host infected with low virulence pthogen Host infected with high virulence pthogen Direct costs > indirect enefits Indirect enefits > direct costs Environmentl Stress Echurd P, Little K, Puli B nd D Lesrrères (2010) Context-dependent effects of Rnvirl infection on Northern Leoprd frog life history trits PLoS One, 10: e Stge susceptiility -Amphiin immune system is stge dependent. -Wild egg msses re often used in l experiments s nïve individuls. 1 Eggs: 320eggs, 160 N.I, 160 I 8*10=80 eggs 40 Inf, 40 non inf used for genetic Check infection N.I1 I *30=240 eggs, 120 Inf, 120 non inf used for tdpole experiment 2 Tdpoles from eggs exposed: 240eg. N.I1 I1 N.I1 I N.I2 I2 4

5 Mortlity reflects infection scenrios I1 I2 >> NI1 I2 > I1 NI2 >> NI1 NI2 Species Comprison 2 3 > 43.3, p < Note: Across 7 Species Hislip NA, Gry MJ, Hovermn JT nd DT Miller (in press) Development nd disese: how susceptiility to n emerging pthogen chnges through nurn development. PLoS One. 5

6 Genotype y genotype interctions Coevolution of host resistnce nd prsite infectivity/virulence Complex Gene : mtching llele Species Strins Wt FV3 Azc SsmeV Temperture Crius et l Evolution Multiple contingency - Length Length (mm), ± SE Temperture (interction ccounted) (F 1,369 =4.348; p=1.78x 10-5 ) 30 COLD WARM COLD WARM 1-Tds smller in cold Length (mm), ± SE Temperture*Strin (F 7,385 =11.96; p=8.11x ) COLD WARM Azc SseMeV Wt Control 2-Strin effect is contingent of Temperture -Control do lwys etter (cold or wrm) -In cold, no diff etween virus strins -Strongest effect of Wt in wrm. Length (mm), ± SE Species*Strin (F 11,385 =11.96; p=6.249x 10-6 ) LF WF1 WF2 Azc SsMeV Wt Control 3-Strin effect is contingent of Species -Control do lwys etter -No genotypic difference for WF1-2 -Strongest effect of Wt in LF only 6

7 Multiple contingency - Weight Temp*Species*Strin (F 23,3369 =7.584; p=2.2x ) Weight (g), ± SE * * * COLD LF COLD WF1 COLD WF2 Weight (g), ± SE 0.8 WARM LF WARM WF1 WARM WF2 0 Azc Control SsMeV Wt Azc Control SsMeV Wt *** *** *** Strin effects re conditionl of oth Temperture nd Species) -Overll effect of infection in cold, regrdless of Species or Strin -Strongest effect of Wt in LF only in Wrm Outside the host-pthogen ox Key role of the environment (density, temperture) infection my e eneficil in stressful environments Key role of the timing of infection conservtion nd experimentl implictions Considerle vrition in life history trits in response to environmentl vrition (temperture, host, virl strin) coevolution nd frequency-dependent selection 7

8 Wht s next Trnsmission Verticl vs. Horizontl Lndscpe genetics of n infection Gene flow vs. Disese dynmics Phylogeogrphy of Rnvirus Metl-Induced Immunosuppression Helth-relted trde-offs Thnks for your ttention 8