TRANSMISION RISK OF DENGUE

Transcription

1 DHF

2 TRANSMISION RISK OF DENGUE

3 VECTOR CONTROL IN MEXICO Paludism Temefos (líquido 5%) B.t.i AS Triflumurón Deltametrina WP (5%) Lambdacihalotrina WP (1%), CS (.75%), M (2.5%) Bifentrina WP (1%) Pemetrina, esbiol y butóxido de piperonilo (= Aquareslin) Cyflutrina a dosis de 1 a 2 g/ha Dengue Temephos (líquido, cápsulas, arena) B.t.i. Pemetrina, esbiol y butóxido de piperonilo (= Aquareslin) Cyflutrina a dosis de 1 a 2 g/ha Bifentrina 1.5% (ULV)

4 ASSESING THE SIGNIFICANCE OF INSECTICIDE RESISTANCE ON Aedes aegypti L. IN MEXICO Laboratorio de Entomología Médica Facultad de Ciencias Biológicas Universidad Autónoma de Nuevo León, MEXICO

5 Research Team P.I. Adriana E. Flores Colaborators: UANL Mexico: Ildefonso Fernandez Salas, Gustavo Ponce, Haydee Loaiza, Guadalupe Reyes, Karla Saavedra CDC Atlanta: William G. Brogdon UC-Ft. Collins: William C. Black IV and Barry Beaty

6 GENERAL OBJECTIVE To establish a resistance surveillance program that provides a practical characterization of the extent (regional distribution) and potential threat of insecticide resistance to vector control in Mexico.

7 Specific aims To provide baseline data for program planning and pesticide selection focally in Mexico. Baseline will be determined on larvae and adults of Ae. aegypti populations to the commonest used and recently introduced chemicals such as: DDT, temephos, malathion, fenthion, permetrin, cyflutrin, biphentrin, deltametrin, lambda-cyalothrin, and propoxur. To determine biochemical characterization of insecticide resistance. To identify resistance genes (kdr) for populations of a Ae. aegypti assisted by PCR techniques

8 STUDY AREAS THREE YEARS April 22-25

9 BIOCHEMICAL CHARACTERIZATION OF RESISTANCE TO THE INSECTICIDES IN ADULT POPULATIONS OF Aedes aegypti (L). IN FIVE MUNICIPALITIES OF THE NORTHERN REGION OF QUINTANA ROO STATE, MEXICO To demonstrate multiple resistance on Ae. aegypti using biochemical assay techniques To ilustrate how enhanced levels of insecticide resistance enzymes may be associated with areas of more extensive use of insecticides

10 Quintana Roo 1.- Benito Juárez 2.- Solidaridad 3.- Lázaro Cárdenas 4.- Cozumel 5.- Isla Mujeres

11 ANOVA α.5 METHODOLOGY Brogdon et al homoginates Head + Torax F1 Y F2 DD frequencies

12 α esterases 8 BENITO JUAREZ COZUMEL % individuals FEMALES MALES FEMALES MALES Absorbance ISLA MUJERES LAZARO CARDENAS 6 FEMALES MALES FEMALES MALES SOLIDARIDAD 8 6 FEMALES MALES

13 β- esterases BENITO JUAREZ COZUMEL 6 FEMALES MALES FEMALES MALES 4 2 % individuals Absorbance ISLA MUJERES LAZARO CARDENAS 6 FEMALES MALES FEMALES MALES SOLIDARIDAD 6 FEMALES MALES

14 MFO 1 BENITO JUAREZ COZUMEL % individuals FEMALES MALES FEMALES MALES Absorbance ISLA MUJERES LAZARO CARDENAS 1 8 FEMALES MALES FEMALES MALES SOLIDARIDAD 1 8 FEMALES MALES

15 Percent of resistance compared to New Orleans strain Biochemical test B. Juarez Cozumel I. Mujeres L. Cardenas Solidaridad Female Male Female Male Female Male Female Male Female Male α-esterases β-esterases MFO GST AChE iache

16 CONCLUSIONS Both α and β esterase assays showed elevated enzyme levels characteristic of resistance mechanisms. These were detected in females of Ae. aegypti and occurred at a much higher frequency in areas of intensive use of insecticide, such as in Benito Juárez and Cozumel (tourist areas). Levels of MFO in females were elevated in Lázaro Cárdenas, suggesting that they have been selected as a detoxifying mechanism

17 CONCLUSIONS These elevated levels were focal, but with a high degree of inter-site variability. Data are consistent with the view that these resistance mechanisms have been under selection by the insecticides used in the area.

18 SUSCEPTIBILITY OF Aedes aegypti L. LARVAE TO MOST COMMON AND ALTERNATIVE INSECTICIDES IN VERACRUZ, MEXICO. Determine the susceptibility of Ae. aegypti to temephos, malathion, permethrin, cypermethrin and biphentrin against this vector s populations from 1 ecological sites of Veracruz state.

19 STUDY AREA 1. Mtz. de la Torre 2. Palma Sola 3. Paso del Cedro 4. Yanga 5. Rdz. Tejeda 6. Dobladero 7. Lerdo de Tejada 8. Sayula de Aleman 9. Cosoleacaque 1. Minatitlán

20 CONCLUSIONS There were no significant differences in susceptibility at LC 5 and LC 95 levels between larval populations of Ae. aegypti among different sites of the study area in Veracruz to biph phenthrin, cypermethri rin,, permethrin methrin,, DDT, malathión and temephos. From an operational perspective, one would not expect an increase in mosquitos control rates with either insecticide

21 VERACRUZ, GULF OF MÉXICO Determine the mechanisms responsible for resistance in three populations of Ae. aegypti selected with.75 permethrin (discriminant dose)

22 STUDY AREA

23 Percent of resistance compared to New Orleans strain Assay ALVARADO COSOLEACAQUE ZEMPOALA L D L D L D α-esterases β-esterases MFO AChE iache GST

24 Conclusions β-esterases is the main resistance mechanisms in all studied regions followed by α esterases but it didn t show any relation with permethrin selected populations. Other resistance mechanisms represent lower contribution in this respect.

25 PENINSULA

26 OBJECTIVES Establish diagnostic dose for permethrin in BCN and BCS. Identify biochemical mechanisms of resistance

27 Baja California Norte Baja California Sur TECATE TIJUANA LORETO C. CONSTITUCION

28 Permethrin DD Mortality proportion % mortality 43mg/mL % mortality 86µg/mL % mortality 11µg/mL % mortality 172µg/mL time

29 α- esterases Tijuana TECATE 4 ALIVE 4 DEAD 4 ALIVE 4 DEAD TECATE TIJUANA

30 α- esterases Loreto 4 ALIVE 4 DEAD LORETO Cd. Constitucion 4 ALIVE 4 DEAD C. CONSTITUCION

31 Percent of resistance compared to New Orleans strain BIOCHEMICAL TEST Cd. Constitución Loreto Tijuana Tecate Alive Dead Alive Dead Alive Dead Alive Dead α-esterases β -esterases AChE iache MFO GST

32 CONCLUSIONS α-esterases were found to be consistently present in permethrin-selected populations and appear to be the principal mechanism of insecticide resistance. β-esterases and GST although present in high proportion, did not reveal a clear pattern of its effect on...

33 NUEVO LEON

34 Permethrin DD % mortality mg/ml 43 mg/ml 64.5mg/ml 86mg/ml 17.5mg/ml time

35 Absorbance No. Mosquitoes No. Mosquitoes No. Mosquitoes INTRODUCTION Bioassay methodology has traditionally been used to determine the insecticide resistance in the field with regards to the mosquitoes, the bioassays require a large number of repetitions (mosquitoes), particularly, when a moderate level of resistance is involved. Furthermore, it is hard to standarize the bioassays plus this method is not adequate for the identification of the resistance mechanisms or the frequency of the resistant phenotypes. There area groups of detoxification enzymes: esterases, oxidases and transferases which are responsible for the development of insecticide resistance in mosquitoes. Brogdon et al (1984, 1988, 199, 1997) developed a microplate assay method in order to determine the activity of Acetilcolinesterase (AChE), Insensitive Acetilcolinesterase (iache), non-especific esterases, Glutation-S-transferase (GST) and Oxidases (MFO) and protein in small samples of homogenized mosquitoes. The microplate assay method for GST, a and b-esterases and MFO was used in this study with the purpose of determining α-esterases San the Pedroactivity of these enzimes on larbal populations of Ae. aegypti, vector of dengue in the metropolitan area of Monterrey, N.L., Mexico Absorbance Abs orbance β-esterases Apodaca 1.3 MFO Villa de Santiago Absorbance BIOCHEMICAL INSECTICIDE RESISTANCE IN Aedes aegypti L. FROM NUEVO LEON, NORTHEASTERN, MEXICO. Adriana E. Flores, Gustavo Ponce G., Mohammad H. Badii and I. Fernández Salas. Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo Leon, Monterrey, Mexico. No. Mosquitoes No. Mosquitoes No. Mosquitoes OBJECTIVES To determine the activity of α and β esterases, MFO and GST in larval populations of Ae. aegypti in the municipalitis of Monterrey, Guadalupe, San Nicolas, Apodaca, Escobedo, San Pedro, Allende, Villa de Santiago and Linares in the State of Nuevo Leon, Mexico. STUDY AREA α-esterases Apodaca Absorbance β -Esterases San Pedro.8 Absorbance Absorbance MFO Monterrey RESULTS No. Mosquitoes No. Mosquitoes No. Mosquitoes No. Mosquitoes METHODOLOGY STUDY AREA. Nine localities from Nuevo Leon state, Northeastern part of Mexico were selected as the study sites. Larvae from each site were collected Weekly and transported to the Medical Entomology Laboratory of the Biological Sciences Faculty in Monterrey, Mexico. ASSAY PROCEDURE Adult mosquitoes were exposed to permethrin (.75%). After the 5% died were separated into two categories, lived and death. The head and thorax were dissected ana homogenizated in phosphate buffer. Fourty five adult mosquitoes were analyzed in triplicate per plate per locality. Five different resistance enzymes were evaluated for each mosquito: acetylcholinesterase (AChE), insensitive acetylcholinesterase (iache), elevated esterases (a, b), elevated mixed-function oxidases (MFO), gluthation-s-transferase (GST) (Brogdon y McAllister,1988).The maximum absorbance value of an A. aegypti susceptible strain (New Orleans, NO) was selected as a resistance threshold Absorbance.2.2 GST Villa de Santiago.21 Absorbance GST Escobedo Absorbance GST San Nicolás GST Monterrey Tolerance levels according to susceptible New Orleans strain of Aedes aegypti populations from different locations of Veracruz, Mexico Locality Assay α Esterases β Esterases GST MFO Monterrey 18.6 San Nicolás 9.3 Apodaca 2. - Guadalupe San Pedro Escobedo 2.3 Allende - Villa de Santiago Linares CONCLUSION It was proved that GST is involved in the insecticide resistance in accordance with the high frequency value observed in Villa de Santiago Ae. aegypti population and less evident in Monterrey. Villa de Santiago is one of the agricultural areas of the Nuevo Leon state and according with this results, the pressure selection in this areas, specially with pyrethroids is very common. THANKS TO THE CONACYT, MEXICO FOR SUPPORTING THIS WORK IN THE PROJECT ASSESING THE SIGNIFICANCE OF INSECTICIDE RESISTANCE ON Aedes aegypti (L.) IN MEXICO, PROJECT NUMBER 3748-N, RESPONSIBLE: Dr. Adriana E. Flores Suárez

36 CONCLUSION It was proved that α-esterases is involved in the insecticide resistance in accordance with the high frequency value observed in Ae. aegypti in 9 Municipalities of Nuevo Leon. Although MFO is present in high proportion there is no relation with permethrin selected populations in Nuevo Leon

37 FACTS The vector program of the Ministry of Health in Mexico has utilized, according to the Official Regulations of Mexico (NOM- 32-SSA), the following insecticides since 196 for the control dengue and malaria: DDT which is currently restricted, but was once used for a long period of time for indoor house spraying; malathion in ultra low volume space-spraying spraying of wide areas for both Anopheles and Aedes mosquitoes; and temephos or 1% Abate granules applied to bodies of water and domestic containers for control of the larvae.