Volume 14, Number 5—May 2008
Research
Efficacy of Aerial Spraying of Mosquito Adulticide in Reducing Incidence of West Nile Virus, California, 2005
Ryan M. Carney*1
, Stan Husted*, Cynthia Jean*, Carol Glaser*, and Vicki Kramer†
, Stan Husted*, Cynthia Jean*, Carol Glaser*, and Vicki Kramer†Table 2
Statistical test results for West Nile virus cases, Sacramento County, California, 2005*
| Area | Goodness of fit† |
Independence‡ |
||
|---|---|---|---|---|
| Pretreatment | Posttreatment | Posttreatment vs. pretreatment | ||
| Treated, both | 0.7508 | <0.0001 | <0.0001 | |
| Treated, northern | 0.0650 | 0.0391 | 0.0053 | |
| Treated, southern | 0.2983 | <0.0001 | 0.0003 | |
| Treated plus buffer, both | 0.6195 | <0.0001 | 0.0005 | |
| Treated plus buffer, northern | 0.1015 | 0.0314 | 0.0069 | |
| Treated plus buffer, southern | 0.4568 | <0.0001 | 0.0029 | |
| Buffer, both | 0.5140 | 0.5744 | 0.3309 | |
| Buffer, northern | 0.5592 | 0.5065 | 0.3745 | |
| Buffer, southern | 0.5990 | 1.0000 | 0.7237 | |
*Numbers of cases were combined for multiple areas; geographically corresponding buffer zones were added where noted. Numbers are 2-tailed p values. Statistically significant associations (p<0.05) are in boldface.
†Exact binomial goodness-of-fit test for observed proportion of cases in listed area(s) to cases in untreated area compared with the expected proportion based on population size estimates.
‡Fisher exact test of independence for 2 × 2 contingency tables containing numbers of pretreatment and posttreatment cases for listed area(s) and the untreated area.
