Metofluthrin: investigations into the use of a volatile spatial pyrethroid in a global spread of dengue, chikungunya and Zika viruses.

Abstract

BACKGROUND:

Metofluthrin reduces biting activity in Aedes aegypti through the confusion, knockdown, and subsequent kill of a mosquito. A geographical spread in dengue, chikungunya, and Zika viruses, increases intervention demands. Response to a Zika outbreak may require a different strategy than dengue, as high-risk individuals, specifically pregnant women, need to be targeted.

METHODS:

In semi-field conditions within a residential property in Cairns, Queensland, the impacts of metofluthrin on biting behaviour of free-flying Wolbachia-infected Ae. aegypti were evaluated.

RESULTS:

Mortality in Ae. aegypti exposed to metofluthrin over a 22 h period was 100% compared to 2.7% in an untreated room. No biting activity was observed in mosquitoes up to 5 m from the emanator after 10 min of metofluthrin exposure. Use of metofluthrin reduced biting activity up to 8 m, regardless of the host's proximity (near or far) to a dark harbourage area (HA) (P < 0.0001 and P = 0.006), respectively. In the presence or absence of the metofluthrin emanator, the host was most likely bitten when located immediately next to a HA (within 1 m) versus 8 m away from the HA (P = 0.006). The addition of a ceiling fan (0.8 m/s airflow) prevented all biting activity after 10 min of metofluthrin exposure. Previously unexposed Ae. aegypti were less likely to reach the host in a metofluthrin-treated room [Formula: see text]= 31%) compared to an untreated room ([Formula: see text]) (P < 0.0001). In a treated room, if the mosquito had not reached the host within 30 s, they never would. Upon activation, the time required for metofluthrin to infiltrate protected locations within a room causing knockdown in caged mosquitoes, required more time than exposed locations (P < 0.003); however exposed and protected locations do eventually reach equilibrium, affecting mosquitoes equally throughout the room.

CONCLUSION:

Metofluthrin is effective in interrupting indoor host-seeking in Ae. aegypti. Metofluthrin's efficacy is increased by centrally locating the emanator in the room, and by using a fan to increase airflow. Newly treated rooms may require a period of 2-4 h for sufficient distribution of the metofluthrin into protected locations where mosquitoes may be resting.

• Authors: Tamara S Buhagiar, Gregor J Devine, Scott A Ritchie
• Journal: Parasites & vectors (Parasit Vectors) Vol. 10 Issue 1 Pg. 270 (May 30 2017) ISSN: 1756-3305 [Electronic] England
• PMID: 28558804 (Publication Type: Evaluation Study, Journal Article)

Chemical References

• Cyclopropanes
• Fluorobenzenes
• Insect Repellents
• (2,3,5,6-tetrafluoro-4-methoxymethylphenyl)methyl-2,2-dimethyl-3-(1-propenyl)cyclopropanecarboxylate

Topics

• Aedes (drug effects, physiology, virology)
• Animals
• Chikungunya Fever (prevention & control, transmission, virology)
• Chikungunya virus (physiology)
• Cyclopropanes (chemistry, pharmacology)
• Dengue (prevention & control, transmission, virology)
• Dengue Virus (physiology)
• Female
• Fluorobenzenes (chemistry, pharmacology)
• Insect Repellents (pharmacology)
• Insect Vectors (drug effects, physiology, virology)
• Mosquito Control (instrumentation, methods)
• Zika Virus (physiology)
• Zika Virus Infection (prevention & control, transmission, virology)