Structuration des populations d'Anopheles funestus et leur

capacité vectrice

Carlo CostantiniFondazione Istituto Pasteur - Cenci Bolognetti et Dept. Santé Publique, Section Parasitologie,

Univ. Rome “La Sapienza”, ItalieCentre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso

carlo.costantini@uniroma1.itcostantini.cnlp@fasonet.bf

The Funestus group

Groupe funestus

sous-groupe funestus

confusus

fuscivenosus

leesoni

rivulorum-brucei

funestus

parensis

aruni

veneedeni

rivulorum

brucei

Figure 1 : Le groupe funestus d'après GILLIES & DE MEILLON (1968) et GILLIES & COETZEE (1987)

Adult bionomics

•Anthropophilic

•Endophagic

•Endophilic

•Longeve

Larval habitat

Large permanent water bodies, e.g.

Swamps

Lake margins

Rice fields

Ditches

Pools

Epidemiological relevance

•Entomological Inoculation Rates up to ~ 400 ibpy

•Extend transmission into the dry seasonPopulation trend in Noungou (Burkina Faso) - Sampling by CDC light traps

0

10

20

30

40

50

60

17-7 31-7 14-8 28-8 11-9 25-9 9-10 23-10 6-11 20-11

rain

(mm

)

1

10

100

1000

mosquitoes/trap

Rainfall An. gambiae complex An. funestus

Chromosomal polymorphism

•No. chromosomes (2n) = 3

•No. paracentric inversions = 15

X

2

3 5

4

b

a

a a

st

20 µ

Chromosomal inversions

Protection of gene linkages from crossing over

Prima anafase meiotica

B. L’inversione noninclude il centromero

C. L’inversioneinclude il centromero

Prima anafase meiotica

A. Appaiamento di cromatidi in uneterozigote per inversione

Methodology

•Observational studies

•Formulation of working hypothesis

•Hypothesis validation

Latitudinal transect

Sampling

Residual fauna

•Indoors(spray-sheet catches,manual aspiration)

•Outdoors(pit-shelters)

Assortative Mating

Fis statistic < 0 = 0 > 0

Hardy-Weinberg equilibriumVillage Chromosomal Arm 3

2N +/+ +/a a/a f(3a) FIS P

November 1992Tougouri 50 0.72 0.16 0.12 0.20 0.52 0.028Noungou 642 0.80 0.09 0.11 0.16 0.62 <0.0001Loumbila 114 0.72 0.12 0.15 0.24 0.67 <0.0001Lembouroudougou 78 0.90 0.03 0.08 0.09 0.85 <0.001Kiribina 100 0.86 0.04 0.10 0.12 0.81 <0.0001Diarabakoko 82 0.54 0.12 0.34 0.40 0.75 <0.0001Folonzo 38 0.11 0.11 0.79 0.84 0.62 0.035

November 1994Loumbila 48 0.58 0.13 0.29 0.35 0.74 <0.001Kiribina 84 0.76 0.12 0.12 0.18 0.60 <0.001Diarabakoko 132 0.38 0.11 0.52 0.57 0.79 <0.0001Folonzo 92 0.02 0.24 0.74 0.86 0.03 ns

Costantini et al. (1999) Parassitologia 41: 595-611

Hardy-Weinberg equilibrium

Sample Chromosomal Arm 3

2N +/+ +/a a/a f(3a) FIS P

Noungou PeulEndophilic 16 0.500 0.500 0.000 0.250 -0.27 ns

Exophilic 18 0.889 0.111 0.000 0.056 —

NoungouEndophilic 1134 0.799 0.106 0.095 0.148 0.58 <0.0001

Exophilic 384 0.849 0.073 0.078 0.115 0.64 <0.0001

LoumbilaEndophilic 316 0.652 0.139 0.209 0.278 0.66 <0.0001

Exophilic 92 0.848 0.065 0.087 0.120 0.70 <0.001

Costantini et al. (1999) Parassitologia 41: 595-611

Chromosomal forms Hp

“Kiribina”-> low-level polymorphism for 2a, 2s, 3a, 3b, 5a

“Folonzo”-> high-level polymorphism for 2a, 3a, 3b, 5a

Costantini et al. (1999) Parassitologia 41: 595-611

Validation: new study area

Validation: new sampling plan

Longitudinal survey:

•Weekly (3x) indoor- and outdoorresting collections

•3 breeding seasons (Sep to Mar)

~15,000 ovaries of which ~2,500karyotyped

Longitudinal survey

Inversion

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Inversion

0.0

0.1

0.2

0.3

0.4

0.5

Inversion

0.0

0.1

0.2

0.3

0.4

0.5

Inversion

0.0

0.1

0.2

0.3

0.4

0.5

Temporal pattern of inversion frequencies (bootstrapped mean ±95% confidence limits)

Hardy-Weinberg equilibrium

Season Locus Koubri KuitiFis P Fis P

1999-2000 2a-s +0.303 0.00 +0.387 0.003a +0.699 0.00 +0.732 0.003b +0.466 0.00 +0.434 0.005a +0.232 0.01 Š0.023 1.00

2000-2001 2a-s +0.335 0.00 +0.279 0.003a +0.660 0.00 +0.719 0.003b +0.375 0.00 +0.358 0.005a +0.218 0.01 Š0.006 1.00

2001-2002 2a-s +0.279 0.00 +0.319 0.003a +0.815 0.00 +0.766 0.003b +0.321 0.00 +0.372 0.005a Š0.004 1.00 Š0.005 1.00

INDOOR samples stratified by breeding season

Hardy-Weinberg equilibrium

OUTDOOR samples stratified by month of collection

X2 Df PSample N Ho He Fis P N Ho He Fis P N Ho He Fis P N Ho He Fis PKoubriSep-99 19 4 5.4 0.27 0.06 20 4 6.6 0.40 0.13 17 1 2.8 0.65 0.09 17 1 1.0 - - 14.6 6.0 0.02Oct-99 47 6 12.2 0.51 0.00 48 3 15.4 0.81 0.00 48 5 8.2 0.40 0.04 45 1 1.0 - - 47.9 6.0 0.00Jan-00 15 - - - - 15 3 4.3 0.31 0.33 15 2 1.9 -0.04 1.00 13 - - - - 2.2 6.0 0.69Nov-00 16 2 3.7 0.47 0.19 18 1 5.8 0.83 0.00 18 1 5.8 0.83 0.00 15 1 1.0 - - 26.6 6.0 0.00Oct-01 27 3 2.9 - 1.00 31 3 12.5 0.76 0.00 28 0 3.8 1.00 0.00 26 - - - - 33.3 6.0 0.00KuitiOct-99 50 8 11.0 0.28 0.02 50 7 18.9 0.63 0.00 48 6 10.6 0.44 0.02 49 2 2.0 0.0 1.0 36.8 6.0 0.00Jan-00 13 2 1.9 -0.04 1.00 16 2 5.0 0.61 0.05 16 2 1.9 -0.03 1.00 14 - - - - 6.0 6.0 0.42Oct-00 16 2 3.7 0.47 0.07 20 1 2.8 0.66 0.08 20 1 2.8 0.66 0.08 15 - - - - 15.7 6.0 0.02Oct-01 13 - - - - 13 0 4.8 1.00 0.00 12 2 1.9 -0.05 1.00 8 - - - - 13.4 6.0 0.01

Arrangement 2Ra-s Arrangement 3Ra Arrangement 3Rb Arrangement 3La

Hardy-Weinberg equilibrium

X2 Df PCompound N Ho He Fis P N Ho He Fis P N Ho He Fis P N Ho He Fis P

Koubri Sep. 991 39 7 9.9 0.30 0.01 41 2 7.3 0.73 0.00 41 4 5.6 0.29 0.18 - - - - - 30.9 6 0.002 40 10 9.2 -0.09 1.00 40 2 10.3 0.81 0.00 40 2 5.6 0.65 0.01 - - - - - 22.8 6 0.079 42 5 6.6 0.25 0.11 43 3 8.2 0.64 0.00 43 1 4.8 0.79 0.00 - - - - - 29.0 6 0.00

Dec. 0115 108 25 33.7 0.26 0.00 122 10 44.4 0.78 0.00 117 14 26.3 0.47 0.00 107 1 1.0 - - 110.4 6 0.0017 120 29 42.9 0.33 0.00 134 5 45.0 0.89 0.00 129 18 28.2 0.36 0.00 114 5 8.7 0.4 0.01 161.8 8 0.0027 70 14 24.0 0.42 0.00 82 5 26.5 0.81 0.00 76 9 13.6 0.34 0.02 73 4 3.9 0.0 1.00 77.0 8 0.0055 62 9 12.0 0.25 0.03 65 0 5.8 1.00 0.00 62 2 2.0 -0.01 1.00 59 - - 30.8 6 0.00

Kuiti Sep. 991 119 21 32.7 0.36 0.00 126 12 26.5 0.55 0.00 123 12 18.4 0.35 0.00 - - - - - 66.9 6 0.007 52 11 15.1 0.27 0.00 53 8 13.7 0.42 0.01 52 8 7.5 -0.07 1.00 - - - - - 22.2 6 0.00

12 45 10 16.6 0.40 0.00 50 5 16.8 0.70 0.00 47 4 10.6 0.62 0.00 - - - - - 49.9 6 0.00Dec. 01

6 102 21 34.3 0.39 0.00 109 9 44.1 0.80 0.00 108 20 28.8 0.31 0.00 104 3 6.8 0.6 0.00 115.8 8 0.007 79 19 26.2 0.28 0.00 81 7 28.7 0.76 0.00 78 13 16.8 0.23 0.08 74 2 1.9 0.0 1.00 61.5 8 0.00

49 80 16 31.2 0.49 0.00 81 5 26.4 0.81 0.00 79 7 16.8 0.59 0.00 73 1 1.0 - - 104.7 6 0.0053 97 14 21.9 0.36 0.00 100 4 16.5 0.76 0.00 97 4 11.3 0.65 0.00 93 3 3.0 0.0 1.00 70.1 8 0.00

Arrangement 2Ra-s Arrangement 3RbArrangement 3Ra Arrangement 3La

Stratified by compound of collection

Linkage disequilibrium

Period Locus pair NS S Test numberSeason1 2Ra-s vs 3Ra 8% 92% 13

2Ra-s vs 3Rb 15% 85% 132Ra-s vs 3La 80% 20% 103Ra vs 3Rb 0% 100% 133Ra vs 3La 90% 10% 103Rb vs 3La 90% 10% 10

Season2 2Ra-s vs 3Ra 0% 100% 132Ra-s vs 3Rb 8% 92% 122Ra-s vs 3La 57% 43% 73Ra vs 3Rb 0% 100% 123Ra vs 3La 43% 57% 73Rb vs 3La 57% 43% 7

Season3 2Ra-s vs 3Ra 8% 92% 132Ra-s vs 3Rb 23% 77% 132Ra-s vs 3La 88% 13% 83Ra vs 3Rb 0% 100% 133Ra vs 3La 56% 44% 93Rb vs 3La 67% 33% 9

Period Locus pair NS S Test numberSep. 99 2Ra-s vs 3Ra 0% 100% 7

2Ra-s vs 3Rb 0% 100% 73Ra vs 3Rb 0% 100% 7

Dec. 01 2Ra-s vs 3Ra 0% 100% 82Ra-s vs 3Rb 13% 88% 82Ra-s vs 3La 71% 29% 73Ra vs 3Rb 0% 100% 83Ra vs 3La 43% 57% 73Rb vs 3La 57% 43% 7

Stratified by breeding season

Stratified by compound of collection

Test of Algorithm

Season Form Locus Koubri KuitiFis P Fis P

1999-2000 Folonzo 2a-s +0.130 0.20 +0.215 0.013a Š0.131 0.22 +0.122 0.123b +0.087 0.38 +0.115 0.145a +0.126 0.26 +0.077 0.36

Kiribina 2a-s +0.008 0.16 Š0.041 0.343a +0.068 0.30 +0.090 0.193b Š0.004 1.00 Š0.007 1.005a Š0.005 1.00 Š0.010 1.00

2000-2001 Folonzo 2a-s +0.274 0.04 +0.133 0.283a Š0.155 0.34 Š0.029 1.003b Š0.028 1.00 Š0.180 0.105a Š0.089 1.00 Š0.017 1.00

Kiribina 2a-s +0.076 0.27 Š0.014 0.453a Š0.031 1.00 Š0.024 1.003b Š0.005 1.00 Š0.004 1.005a +0.437 0.00 Š0.003 1.00

2001-2002 Folonzo 2a-s +0.160 0.15 +0.168 0.053a +0.104 0.20 Š0.047 0.743b Š0.114 0.22 Š0.022 0.885a Š0.008 1.00 Š0.009 1.00

Kiribina 2a-s +0.094 0.14 +0.023 0.673a Š0.016 1.00 Š0.018 1.003b Š0.002 1.00 Š0.004 1.005a Š0.002 1.00 Š0.001 1.00

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10111213141516

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Deviance Folonzo

Maximum Likelihood Assignment Test

99.5% of 395 individuals assigned according to the algorithm

Temporal distribution

Koubri

Kuiti

Folonzo Kiribina

Nov Jan

Mar

Sep

Nov Jan

Mar

Sep

Nov Jan

Mar

Spatial distributionIndoor resting samples collected over one week• 52 sampled compounds (~ 50% of whole village)• 812 scorable karyotyped specimens

Longitude

Latit

ude

Kriging of inversion 3a frequency

Epidemiological parameters

Sample N Chromosomal Form

Folonzo Kiribina

Frequency HBI CSP +ve Frequency HBI CSP +ve

NoungouEndophilic 533 (528) 0.167 0.921 0.146 0.833 0.948 0.110

Exophilic 164 (159) 0.134 0.909 0.045 0.866 0.628 0.063

Pooled 697 (687) 0.159 0.919 0.126 0.841 0.872 0.099

LoumbilaEndophilic 154 (153) 0.292 0.822 0.089 0.708 0.750 0.055

Exophilic 44 (42) 0.182 0.500 0.125 0.818 0.441 0.028

Pooled 198 (195) 0.268 0.774 0.094 0.732 0.676 0.048

New approaches: STRs

32 microsatellite loci mapped by FISH dispersed over all chromosomes

Set of 16 locatedOUTSIDE main inversions chosen for metapopulation analyses

The team

Centre National de Recherche et Formation sur le Paludisme, Burkina Faso•N’Falé Sagnon•Wamdaogo Moussa Guelbeogo

Istituto Superiore di Sanità, Laboratorio di Parassitologia, Italy•Daniela Boccolini

Dept. Biological Sciences, Univ. Notre Dame, USA•Nora Besansky•Olga Grushko•Igor Sharakhov•Brandon Hackett Schemerhorn•Andy Michel•Matt Ingrasci