Correlation between aerial insecticide spraying to interrupt west nile virus transmission and emergency department visits in sacramento county, california.
ABSTRACT Insecticides reduce vector-borne pathogen transmission but also pose health risks. In August 2005, Sacramento County, California, underwent emergency aerial ultralow-volume (ULV) application of pyrethrin insecticide to reduce the population of West Nile virus (WNV)-infected mosquitoes and thereby interrupt enzootic and tangential transmission. We assessed the association between aerially applied pyrethrin insecticide and patterns of emergency department (ED) visit diagnoses.
We used geographic information systems software to determine ZIP Code-level exposure to pyrethrin. We used logistic regression models to examine the relationship between exposure status and three-digit International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) codes (785 in total) for all ED visits (n=253,648) within Sacramento County in 2005 and for specific diagnostic clusters (e.g., respiratory, gastrointestinal, skin, eye, and neurologic). All models were adjusted for age, gender, race/ethnicity (individual level), median income, ozone, and temperature (ZIP Code level).
Exposure to aerially applied insecticide was not associated with clusters of respiratory, gastrointestinal, skin, eye, and neurologic complaints in adjusted models but was inversely associated with ICD-9-CM code 799 ("other ill-defined morbidity and mortality"), with adjusted odds ratios (AORs) ranging from 0.31 to 0.36 for 0-3 lag days (95% confidence interval 0.17, 0.68). Spraying was also directly associated with ICD-9-CM code 553 ("other abdominal hernia"), with AORs ranging from 2.34 to 2.96 for 2-3 lag days.
The observed significant ICD-9-CM code associations likely represented chance findings. Aerial ULV pyrethrin applications were not associated with ED visits for specific diagnoses or clusters of diagnoses.
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ABSTRACT: Dengue virus (DENV) spreads to humans through the bite of an infected Aedes aegypti or Aedes albopictus mosquito and is a growing public health threat to both industrialized and developing nations worldwide. Outbreaks of autochthonous dengue in the United States occurred extensively in the past but over the past 3 decades have again taken place in Florida, Hawaii, and Texas as well as in American Samoa, Guam, Northern Mariana Islands, Puerto Rico, and the US Virgin Islands. As the Aedes vectors spread worldwide it is anticipated that DENV as well as other viruses also transmitted by these vectors, such as Chikungunya virus (CHKV), will invade new areas of the world, including the United States. In this review, we describe the current burden of dengue disease worldwide and the potential introduction of DENV and CHKV into different areas of the United States. Of these areas, the state of California saw the arrival and spread of the Aedes aegypti vector beginning in 2013. This invasion presents a developing situation when considering the state's number of imported dengue cases and proximity to northern Mexico as well as the rising specter of chikungunya in the Western hemisphere. In light of the recent arrival of Aedes aegypti mosquito vectors to California, there is now a small but appreciable risk for endemic transmission of dengue and chikungunya within the State. It is likely, however, that if DENV or CHKV were to become endemic that the public health situation would be similar to that currently found along the Texas-Mexico border. The distribution of Aedes vectors in California as well as a discussion of several factors contributing to the risk for dengue importation are discussed and evaluated. Dengue and chikungunya viruses present real risks to states where the Aedes vector is now established. Scientists, physicians, and public health authorities should familiarize themselves with these risks and prepare appropriately. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.11/2014; 80(6):466-475. DOI:10.1016/j.aogh.2015.02.006
- Annals of Epidemiology 09/2013; 23(9):589. DOI:10.1016/j.annepidem.2013.06.046 · 2.15 Impact Factor
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ABSTRACT: During 2012, four north-central Texas counties experienced high West Nile virus (WNV) disease incidence. Aerial insecticide spraying was conducted in two counties. To evaluate the effect of spraying on WNV disease, we calculated incidence rate ratios (IRRs) in treated and untreated areas by comparing incidence before and after spraying; for unsprayed areas, before and after periods were defined by using dates from a corresponding sprayed area. In treated areas, WNV neuroinvasive disease incidence before and after spraying was 7.31/100,000 persons and 0.28/100,000 persons, respectively; the IRR was 26.42 (95% confidence interval [CI]: 12.42-56.20). In untreated areas, the before and after incidence was 4.80/100,000 persons and 0.45/100,000 persons, respectively; the IRR was 10.57 (95% CI: 6.11-18.28). The ratio of IRRs was 2.50 (95% CI: 0.98-6.35). Disease incidence decreased in both areas, but the relative change was greater in aerial-sprayed areas.The American journal of tropical medicine and hygiene 04/2014; 91(2). DOI:10.4269/ajtmh.14-0072 · 2.74 Impact Factor