Background
Methods
Study sites
Site | GPS coordinates | Anopheles stephensi present | |||||
---|---|---|---|---|---|---|---|
2018 | 2019 | 2020 | |||||
Larval collections | Adult collections | Larval collections | Adult collections | Larval collections | Adult collections | ||
Assosa | 10.062880, 34.543805 | − | |||||
Awash Sebat Kilo | 8.988937, 40.160936 | + | + | + | + | Urban (+)/rural (+) | + |
Bahirdar | 11.591264, 37.381047 | − | |||||
Bati | 11.191347, 40.014825 | + | + | Rural (+) | |||
Degehabur | 8.223978, 43.558388 | + | + | Rural (+) | |||
Dire Dawa | 9.602669, 41.840532 | + | + | + | + | Urban (+)/rural (+) | + |
Erer Gota | 9.555372, 41.384327 | + | + | ||||
Gambela | 8.247653, 34.594831 | − | |||||
Gewane | 10.157669, 40.660508 | + | + | + | Rural (+) | ||
Godey | 5.952589, 43.556624 | + | + | Urban (+)/rural (+) | |||
Hawassa | 7.053381, 38.489377 | − | |||||
Jigjiga | 9.353974, 42.795313 | + | + | ||||
Jimma | 7.669907, 36.837115 | − | |||||
Kebridehar | 6.734321, 44.276404 | + | + | + | Rural (+) | + | |
Meki | 8.152866, 38.823858 | + | Urban (+)/rural (−) | ||||
Metehara | 8.901551, 39.917774 | + | + | Urban (+)/rural (+) | + | ||
Negelle-Borena | 5.336451, 39.575286 | − | |||||
Semera | 11.792397, 41.010032 | + | + | + | Rural (+) | ||
Shire | 14.101822, 38.28188 | − | |||||
Yabello | 4.893769, 38.097239 | − | |||||
Zeway | 7.924096, 38.719499 | + | Urban (+)/rural (−) |
Mosquito collection
Collection of larvae and pupae
Collection of adult mosquitoes
Blood meal analysis
Detection of Plasmodium sporozoites
Insecticide susceptibility tests
Piperonyl butoxide synergist assays
Resistance intensity
Results
Distribution of Anopheles stephensi
Urban site | Larval habitat type | Total Anopheles larvae collected | An. stephensi | An. gambiae s.l | An. rhodesiensis | An. cinereus |
---|---|---|---|---|---|---|
Negelle-Borena | Water containers | 55 | 0 | 13 | 0 | 0 |
Water tanks | 66 | 0 | 11 | 0 | 1 | |
Stagnant water pools | 211 | 0 | 132 | 0 | 0 | |
Yabello | Water tanks | 39 | 0 | 13 | 0 | 0 |
Stagnant water pools | 55 | 0 | 23 | 0 | 0 | |
Cement water reservoirs | 194 | 0 | 90 | 15 | 0 | |
Jimma | Rain pools and puddles | 378 | 0 | 148 | 0 | 0 |
Gambela | Rain pools and puddles | 143 | 0 | 61 | 0 | 0 |
Assosa | Discarded tyres | 150 | 0 | 86 | 0 | 0 |
Rain pools and puddles | 1618 | 0 | 1266 | 0 | 0 | |
Natural habitats | 710 | 0 | 531 | 0 | 0 | |
Bahirdar | Tyres | 1681 | 0 | 1213 | 0 | 0 |
Stagnant water pools | 807 | 0 | 294 | 0 | 0 | |
Meki | Tyres | 45 | 24 | 0 | 0 | 0 |
Concrete water container | 68 | 43 | 20 | 0 | 0 | |
Water tanks | 36 | 19 | 10 | 0 | 0 | |
Discarded buckets | 2 | 0 | 1 | 0 | 0 | |
Zeway | Tyres | 24 | 14 | 0 | 0 | 0 |
Water drums | 1 | 0 | 0 | 0 | 0 | |
Concrete water containers | 12 | 3 | 5 | 0 | 0 | |
Hawassa | Water drums | 7 | 0 | 5 | 0 | 0 |
Concrete water containers | 6 | 0 | 4 | 0 | 0 | |
Waste bin | 12 | 0 | 9 | 0 | 0 | |
Plastic bucket | 4 | 0 | 4 | 0 | 0 | |
Shire | Tyres | 14 | 0 | 14 | 0 | 0 |
Rain pools and puddles | 2327 | 0 | 990 | 0 | 0 | |
Natural habitats | 208 | 0 | 130 | 0 | 0 | |
Metehara | Water tanks | 1075 | 322 | 0 | 0 | 0 |
Nearest town | Number of visited kebeles | Number of kebeles positive for An. stephensi | Number of potential larval sites inspected | Number of larval sites positive for An. stephensi (%) | Number of larval sites positive for Aedes (%) | Number of An. stephensi larval sites also containing Aedes larvae (%) |
---|---|---|---|---|---|---|
Awash | 1 | 1 | 3 | 1 (33) | 1 (33) | 1 (100) |
Bati | 7 | 3 | 165 | 6 (4) | 42 (25) | 4 (67) |
Degehabur | 6 | 2 | 32 | 7 (22) | 7 (22) | 2 (29) |
Dire Dawa | 7 | 2 | 17 | 2 (12) | 8 (47) | 2 (100) |
Gewane | 4 | 3 | 127 | 10 (8) | 24 (19) | 7 (70) |
Godey | 6 | 1 | 24 | 1 (4) | 6 (25) | 0 |
Kebridehar | 8 | 6 | 40 | 13 (33) | 6 (15) | 0 |
Meki | 5 | 0 | 17 | 0 | 0 | 0 |
Metehara | 3 | 1 | 12 | 1 (8) | 2 (17) | 0 |
Semera | 5 | 2 | 136 | 3 (2) | 22 (16) | 2 (67) |
Zeway | 3 | 0 | 16 | 0 | 0 | 0 |
Total | 55 | 21 | 589 | 44 (7) | 118 (20) | 18 (40) |
Anopheles stephensi in longitudinal surveillance sites
Month 2019 | Dire Dawa | Kebridehar | Awash Sebat Kilo | Metehara | ||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
PSC | HLC | CDC light trap | Hand Collection | Black resting box | Cattle-baited Tent Trap | Total | PSC | HLC | CDC light trap | Hand Collection | Black resting box | Cattle-baited Tent Trap | Total | PSC | HLC | CDC light trap | Hand Collection | Cattle-baited Tent Trap | Total | PSC | HLC | CDC light trap | Hand Collection | Cattle-baited Tent Trap | Total | |
June | 0 | 0 | 0 | ND | 0 | ND | 0 | 4 | 1 | 3 | ND | 0 | ND | 8 | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND |
July | 3 | 0 | 0 | 18 | 0 | ND | 21 | 1 | 0 | 0 | 0 | 0 | ND | 1 | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND |
August | 1 | 0 | 0 | 127 | 16 | 16 | 160 | 2 | 0 | 0 | 5 | 0 | 6 | 13 | 0 | 4 | 0 | 20 | ND | 24 | 1 | 4 | 0 | 2 | ND | 7 |
September | 0 | 0 | 3 | 24 | 82 | 9 | 118 | 4 | 0 | 0 | 19 | 0 | 18 | 41 | 0 | 2 | 0 | 36 | 10 | 48 | 5 | 7 | 18 | 19 | 4 | 53 |
October | 0 | 0 | 1 | 26 | 56 | 9 | 92 | 1 | 4 | 0 | 79 | 0 | 29 | 113 | 2 | 1 | 0 | 37 | 10 | 50 | 2 | 0 | 2 | 12 | 5 | 21 |
November | 0 | 0 | 0 | 5 | 2 | 6 | 13 | 3 | 0 | 0 | 46 | 0 | 29 | 78 | 0 | 0 | 0 | 11 | 1 | 12 | 1 | 0 | 0 | 3 | 3 | 7 |
December | 0 | 0 | 0 | 5 | 3 | 0 | 8 | 14 | 0 | 0 | 63 | 0 | 37 | 114 | 1 | 0 | 0 | 19 | 0 | 17 | 0 | 0 | 3 | 9 | 6 | 18 |
Total | 4 | 0 | 4 | 205 | 159 | 40 | 412 | 29 | 5 | 3 | 212 | 0 | 119 | 368 | 3 | 7 | 0 | 123 | 21 | 154 | 9 | 11 | 23 | 45 | 18 | 106 |
Blood meal identification
Anopheles stephensi infection with Plasmodium falciparum and Plasmodium vivax sporozoites
Insecticide susceptibility
Type of assay | Insecticide class | Insecticide | Concentration | Percentage mortality (number tested) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
2018 | 2019 | 2020 | ||||||||||||
Dire Dawa | Kebridehar | Dire Dawa | Kebridehar | Gewane | Semera | Awash Sebat Kilo | Awash Sebat Kilo | Meki | Metehara | Godey | ||||
Diagnostic dose | Pyrethroids | Permethrin | 0.75% | 79 (100) | 78 (100) | 86 (100) | 76 (100) | 68 (100) | 67 (100) | 39 (100) | 43 (100) | 72 (100) | 93 (100) | 10 (100) |
Deltamethrin | 0.05% | 54 (100) | 80 (100) | 64 (100) | 74 (100) | 31 (100) | 37 (100) | 68 (100) | 15 (100) | 59 (100) | 17 (100) | 7 (100) | ||
Alpha-cypermethrin | 0.05% | 82 (100) | 80 (100) | 30 (100) | 64 (100) | 20 (100) | 51 (100) | 69 (100) | 10 (100) | 33 (100) | 62 (100) | 1 (100) | ||
Carbamates | Bendiocarb | 0.05% | 19 (100) | 73 (100) | 4 (100) | 17 (100) | 60 (100) | 57 (100) | 5 (100) | 13 (100) | 4 (100) | 7 (100) | 20 (100) | |
Propoxur | 0.10% | 77 (100) | 68 (100) | 59 (100) | 38 (100) | 77 (100) | 99 (100) | 73 (100) | 19 (100) | 9 (100) | 17 (100) | 79 (100) | ||
Organophosphates | Pirimiphos-methyl | 0.25% | 100 (100) | 100 (100) | 27 (100) | 49 (100) | 92 (100) | 99 (100) | 93 (100) | 1 (100) | 0 (100) | 35 (100) | 67 (100) | |
Synergist assays | Pyrethroids | Permethrin | 0.75% | 69 (75) | 85 (75) | 70 (75) | 43 (75) | 43 (75) | 16 (75) | |||||
Permethrin + PBO | 0.75%/4% | 100 (75) | 100 (75) | 100 (75) | 100 (75) | 100 (75) | 100 (75) | |||||||
Deltamethrin | 0.05% | 45 (75) | 49 (75) | 67 (75) | 61 (75) | 21 (75) | 57 (75) | 39 (75) | 4 (75) | |||||
Deltamethrin + PBO | 0.05%/4% | 96 (75) | 100 (75) | 97 (75) | 100 (100) | 100 (75) | 100 (75) | 99 (75) | 92 (75) | |||||
Alpha-cypermethrin | 0.05% | 83 (75) | 31 (75) | 25 (75) | 9 (75) | 8 (75) | ||||||||
Alpha-cypermethrin + PBO | 0.05%/4% | 100 (75) | 93 (75) | 100 (75) | 100 (75) | 96 (75) |
Temephos susceptibility test results
Site | LC50 (95% CI) mg/L | LC95 (95% CI) mg/L |
---|---|---|
Dire Dawa | 0.105 (0.099–0.109) | 0.118 (0.114–0.113) |
Kebridehar | 0.019 (0.015–0.027) | 0.031 (0.024–0.122) |
Meki | 0.012 (0.011–0.013) | 0.025 (0.021–0.032) |