Pyrethroid insecticides in urban catch basins: A potential secondary contamination source for urban aquatic systems.

Pesticide contamination is a threat to many aquatic habitats, and runoff from residential homes is a major contributor of these chemicals in urban surface streams and estuaries. Improved understanding of their fate and transport can help identify areas of concern for monitoring and management. In many urban areas, runoff water congregates in numerous underground catch basins before draining into the open environment; however, at present essentially no information is available on pesticide presence in these systems.

Emerging Mosquito Resistance to Piperonyl Butoxide-Synergized Pyrethroid Insecticide and Its Mechanism.

Piperonyl butoxide (PBO)-synergized pyrethroid products are widely available for the control of pyrethroid-resistant mosquitoes. To date, no study has examined mosquito resistance after pre-exposure to PBO and subsequent enzymatic activity when exposed to PBO-synergized insecticides. We used Culex quinquefasciatus Say (Diptera: Culicidae), an important vector of arboviruses and lymphatic filariasis, as a model to examine the insecticide resistance mechanisms of mosquitoes to PBO-synergized pyrethroid using modified World Health Organization tube bioassays and biochemical analysis of metabolic enzyme expressions pre- and post-PBO exposure.

Impact of underground storm drain systems on larval ecology of Culex and Aedes species in urban environments of Southern California.

An extensive network of storm water conveyance systems in urban areas, often referred to as the "underground storm drain system" (USDS), serves as significant production habitats for mosquitoes. Knowledge of whether USDS habitats are suitable for newly introduced dengue vectors Aedes aegypti and Ae. albopictus will help guide surveillance and control efforts.

Cross Resistance in S-Methoprene-Resistant Culex quinquefasciatus (Diptera: Culicidae).

The juvenile hormone analog S-methoprene is the only synthetic biopesticide that is registered with the United States Environmental Protection Agency to control arthropods of economic importance in public health, livestock, pets, urban, and stored products. The high activity, relative target specificity, and benign environmental profile of S-methoprene have been well documented. While the risk of resistance in mosquitoes to S-methoprene is generally low, there is a lack of information regarding cross resistance in S-methoprene-resistant mosquitoes to other pesticides.

Rickettsial Infections among Cats and Cat Fleas in Riverside County, California.

Presently, few studies have investigated the role of domestic cats () in the recrudescence of flea-borne rickettsioses in California and the southern United States. In this study, we aimed to investigate the presence of or in domestic cats () and the fleas (primarily , the cat flea) associated with these cats in Riverside County, California. Thirty cats and 64 pools of fleas collected from these cats were investigated for rickettsial infections.

Rickettsial Infections among Ctenocephalides felis and Host Animals during a Flea-Borne Rickettsioses Outbreak in Orange County, California.

Due to a resurgence of flea-borne rickettsioses in Orange County, California, we investigated the etiologies of rickettsial infections of Ctenocephalides felis, the predominant fleas species obtained from opossums (Didelphis virginiana) and domestic cats (Felis catus), collected from case exposure sites and other areas in Orange County. In addition, we assessed the prevalence of IgG antibodies against spotted fever group (SFGR) and typhus group (TGR) rickettsiae in opossum sera. Of the 597 flea specimens collected from opossums and cats, 37.

Genetic analysis of invasive Aedes albopictus populations in Los Angeles County, California and its potential public health impact.

The Asian tiger mosquito, Aedes albopictus, is an anthropophilic aggressive daytime-biting nuisance and an efficient vector of certain arboviruses and filarial nematodes. Over the last 30 years, this species has spread rapidly through human travel and commerce from its native tropical forests of Asia to every continent except Antarctica. In 2011, a population of Asian tiger mosquito (Aedes albopictus) was discovered in Los Angeles (LA) County, California.

SEARCH: Spatially Explicit Animal Response to Composition of Habitat.

Complex decisions dramatically affect animal dispersal and space use. Dispersing individuals respond to a combination of fine-scale environmental stimuli and internal attributes. Individual-based modeling offers a valuable approach for the investigation of such interactions because it combines the heterogeneity of animal behaviors with spatial detail.

Two pathogens and one disease: detection and identification of flea-borne Rickettsiae in areas endemic for murine typhus in California.

Results of an environmental assessment conducted in a newly emergent focus of murine typhus in southern California are described. Opossums, Didelphis virginiana Kerr, infested with cat fleas, Ctenocephalides felis Buché, in the suburban area were abundant. Animal and flea specimens were tested for the DNA of two flea-borne rickettsiae, Rickettsia typhi and Rickettsia felis.

Host (avian) biting preference of southern California Culex mosquitoes (Diptera: Culicidae).

The host preference of a vector mosquito species plays a significant role in determining human and animal risk of infection with mosquito-transmitted pathogens. Host preferences of common southern California Culex species for four bird species, American crow (Corvus brachyrhynchos), house sparrow (Passer domesticus), house finch (Carpodacus mexicanus), and mourning dove (Zenaida macroura), were examined by determining the proportion of each mosquito species that successfully engorged on each of the four bird species presented equally within a net trap to wild host-seeking mosquitoes. Bloodmeals in engorged mosquitoes captured within the net trap were identified to avian species by using a multiplex polymerase chain reaction assay targeting the cytochrome b gene sequence.

Surveillance for West Nile virus and vaccination of free-ranging island scrub-jays (Aphelocoma insularis) on Santa Cruz Island, California.

Transmission of West Nile virus (WNV) on mainland California poses an ongoing threat to the island scrub-jay (ISSJ, Aphelocoma insularis), a species that occurs only on Santa Cruz Island, California, and whose total population numbers <5000. Our report describes the surveillance and management efforts conducted since 2006 that are designed to understand and mitigate for the consequences of WNV introduction into the ISSJ population. We suspect that WNV would most likely be introduced to the island via the movement of infected birds from the mainland.

Vector-host interactions governing epidemiology of West Nile virus in Southern California.

Southern California remains an important focus of West Nile virus (WNV) activity, with persistently elevated incidence after invasion by the virus in 2003 and subsequent amplification to epidemic levels in 2004. Eco-epidemiological studies of vectors-hosts-pathogen interactions are of paramount importance for better understanding of the transmission dynamics of WNV and other emerging mosquito-borne arboviruses. We investigated vector-host interactions and host-feeding patterns of 531 blood-engorged mosquitoes in four competent mosquito vectors by using a polymerase chain reaction (PCR) method targeting mitochondrial DNA to identify vertebrate hosts of blood-fed mosquitoes.

Economic conditions predict prevalence of West Nile virus.

Understanding the conditions underlying the proliferation of infectious diseases is crucial for mitigating future outbreaks. Since its arrival in North America in 1999, West Nile virus (WNV) has led to population-wide declines of bird species, morbidity and mortality of humans, and expenditures of millions of dollars on treatment and control. To understand the environmental conditions that best explain and predict WNV prevalence, we employed recently developed spatial modeling techniques in a recognized WNV hotspot, Orange County, California.

The effectiveness of botulinum A toxin as an adjunct to the treatment of clubfeet by the Ponseti method: a randomized, double blind, placebo controlled study.

Background: The Ponseti method has been shown to be a highly effective way to correct congenital clubfeet nonoperatively. Children treated with the technique frequently require percutaneous Achilles tenotomies, however, and until recently have experienced frequent relapses of their deformity. The purpose of this study was to see if Botulinum a A toxin (BTX-A) (manufactured by Allergan, Irvine CA) and administered before starting treatment with the Ponseti method might decrease the time in cast to correction, reduce the need for percutaneous Achilles tenotomy, and reduce the frequency of relapse.

Triplane ankle fracture with deltoid ligament tear and syndesmotic disruption.

In patients with immature skeletons, ligamentous injuries rarely accompany ankle fractures. In this article, we report about deltoid ligament tears and syndesmotic disruptions accompanying triplane ankle fractures in two children, and make recommendations as to the evaluation and treatment of children with such injuries.