Cryptic Mosquitoes: Hide and Seek and Treat? Symposium II
Cryptic Mosquitoes: Hide and Seek and Treat? Symposium II
The Southern Nevada Health District (SNHD) is the local governmental public health authority for southern Nevada, serving a population of over 2 million residents. Clark County is the southernmost county in Nevada and is composed of 5 municipalities and 1 county government: the city of Las Vegas, city of North Las Vegas, city of Henderson, city of Mesquite, Boulder City, and unincorporated Clark County.
Since 2005, SNHD has maintained a mosquito disease surveillance program to monitor mosquito populations, test for arboviruses and educate the community on breeding source elimination and bite prevention. SNHD does not conduct abatement and there is no single coordinated mosquito control program in Clark County.
In 2014 SNHD purchased Aeded aegypti specific surveillance equipment and in May, 2017 detected this vector for the first time in the city of North Las Vegas. Ongoing surveillance has documented the rapid spread of Ae. aegypti across Clark County, with species-positive traps in 6 zip codes in 2021, 12 in 2022 and 32 in 2023.
In addition to the rapid expansion, Ae. aegypti counts at residential trap sites have dramatically increased. Clark County experienced an abnormally high amount of rainfall in 2023 and complaints of mosquito activity to SNHD’s mosquito surveillance hotline increased from 99 in 2022 to 327 in 2023. Ae. aegypti was trapped at most of these homes. This trend of increased calls for service will continue as Ae. aegypti entrench themselves in communities.
The initial Ae. aegypti samples were submitted to Yale University for genetic analysis, which determined they were most likely introduced from southern California. Recent, longitudinal samples have been submitted to the University of Nevada, Las Vegas for whole genome sequencing, to establish whether the contemporary expansion of Ae. aegypti across Clark County reflects endemic dispersal or multiple reintroduction events from neighboring States.