Trends in rural and urban deliveries and vaginal births: California 1998-2002.

Context: Pregnant women in rural areas may give birth in either rural or urban hospitals. Differences in outcomes between rural and urban hospitals may influence patient decision making.

Purpose: Trends in rural and urban obstetric deliveries and neonatal and maternal mortality in California were compared to inform policy development and patient and provider decision making in rural health care settings.

Vaginal birth after cesarean in California: before and after a change in guidelines.

Purpose: In 1999 the American College of Obstetricians and Gynecologists (ACOG) adopted more-restrictive guidelines for vaginal birth after cesarean delivery (VBAC). This study assesses trends in VBAC in California and compares neonatal and maternal mortality rates among women attempting VBAC delivery or undergoing repeat cesarean delivery before and after this guideline revision.

Methods: The 1996 through 2002 California Birth Statistical Master Files were used to identify 386,232 California residents who previously gave birth by cesarean delivery and had a singleton birth planned in a California hospital.

Influence of temperature and concentration of VectoBac on control of the salt-marsh mosquito, Ochlerotatus squamiger, in Monterey County, California.

Laboratory susceptibility bioassays were conducted to determine the efficacy of VectoBac TP (Bacillus thuringiensis var. israelensis [Bti]) at different concentrations and temperatures against the salt-marsh mosquito Ochlerotatus squamiger. Bioassays on late 3rd- and early 4th-stage larvae, read at 72 h and 14 degrees C produced an LD90 of 0.

Pyrethroid tolerance in Culex pipiens pipiens var molestus from Marin County, California.

In May 2001 a sample of Culex pipiens pipiens variety molestus Forskål from Marin County, California, collected as larvae and reared to adults, was found to show reduced resmethrin and permethrin knock-down responses in bottle bioassays relative to a standard susceptible Cx. pipiens quinquefasciatus Say colony (CQ1). Larval susceptibility tests, using CQ1 as standard susceptible, indicated that the Marin mosquitoes had LC50 resistance ratios of 18.

Differences in extent of genetic introgression between sympatric Culex pipiens and Culex quinquefasciatus (Diptera: Culicidae) in California and South Africa.

Comparisons of five morphological characters, 12 enzyme electrophoresis profiles, and Wolbachia pipientis infection rates were used to characterize populations of members of the Culex pipiens L. complex in California and South Africa. In South Africa, male phallosome DV/D ratio, male maxillary palp index, branching of siphonal seta 1a, the enzyme locus Mdhp-1, and W.

High level methoprene resistance in the mosquito Ochlerotatus nigromaculis (Ludlow) in central California.

In the summer of 1998, failures of methoprene field applications to control the mosquito Ochlerotatus nigromaculis (Ludlow) were noticed in several pastures in the outskirts of Fresno, California, USA. Effective control with methoprene had been achieved for over 20 years prior to this discovery. Susceptibility tests indicated that the Fresno Oc nigromaculis populations had developed several thousand-fold higher LC50 and LC90 tolerance levels to methoprene compared with methoprene-naïve populations.