The Experts below are selected from a list of 789 Experts worldwide ranked by ideXlab platform
Kristen B. Healy - One of the best experts on this subject based on the ideXlab platform.
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Effects of truck-mounted, ultra low volume mosquito adulticides on honey bees (Apis mellifera) in a suburban field setting.
PloS one, 2018Co-Authors: Vivek Pokhrel, James A. Ottea, Nicholas Delisi, Robert G. Danka, Todd W. Walker, Kristen B. HealyAbstract:Few studies have examined the impact of mosquito adulticides on honey bees under conditions that reflect actual field exposure. Whereas several studies have evaluated the toxicity of mosquito control products on honey bees, most have been laboratory based and have focused solely on acute mortality as a measure of impact. The goal of this study was to determine effects of routine applications of truck-based ultra-low volume (ULV) mosquito adulticides (i.e., Scourge, Duet, and Deltagard) on honey bees in a suburban setting. The mosquito adulticides used in this study were pyrethroids with active ingredients Resmethrin (Scourge), prallethrin and sumithrin (Duet), and deltamethrin (Deltagard), in which Resmethrin, prallethrin, and sumithrin were synergized with piperonyl butoxide. We measured and compared mortality and detoxification enzyme activities (esterase and glutathione S-transferase) from sentinel beehives within and outside of mosquito control areas. Concurrently, colony health (i.e., number of adult bees, brood quantity and brood quality) was compared throughout the study period. No significant differences were observed in honey bee mortality, colony health or detoxification enzyme activities between treated (five sprayed areas each received one to three insecticide treatment) and control sites (four unsprayed areas that did not receive insecticide treatment) over the seven week study period. However, our laboratory study showed that exposure to Resmethrin, the active ingredient in Scourge, caused significant inhibition of esterase activity compared with the control group. Our findings suggest that proper application of truck based insecticides for mosquito control results in little or no exposure and therefore minimal effects on domestic honey bees.
Erik K. Hofmeister - One of the best experts on this subject based on the ideXlab platform.
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Testing independent and interactive effects of corticosterone and synergized Resmethrin on the immune response to West Nile virus in chickens.
Toxicology, 2010Co-Authors: Mark D. Jankowski, J. Christian Franson, Erich Möstl, Warren P. Porter, Erik K. HofmeisterAbstract:Abstract Public health agencies utilize aerial insecticides to interrupt an active West Nile virus (WNV) transmission cycle, which may expose WNV-infected birds to these agents. Although Resmethrin has been considered benign to birds, no studies have evaluated whether the environmentally employed form of Resmethrin with PBO synergist (synergized Resmethrin (SR)) can suppress avian immunity to WNV infection and enhance a bird's host competence. Recognizing that wild birds confront toxicological stressors in the context of various physiological states, we exposed four groups ( n = 9–11) of 9-week-old chickens ( Gallus domesticus ) to drinking water with either SR (three alternate days at 50 μg/l Resmethrin + 150 μg/l piperonyl butoxide), CORT (10 days at 20 mg/l to induce subacute stress), the combination of SR and CORT, or 0.10% ethanol vehicle coincident with WNV infection. Compared to controls, SR treatment did not magnify but extended viremia by 1 day, and depressed IgG; CORT treatment elevated (mean, 4.26 log 10 PFU/ml) and extended viremia by 2 days, enhanced IgM and IgG, and increased oral virus. The combination of SR and CORT increased the number of chickens that shed oral virus compared to those treated with CORT alone. None of the chickens developed a readily infectious viremia to mosquitoes (none ≥5 log 10 PFU/ml), but viremia in a CORT-exposed chicken was up to 4.95 log 10 PFU/ml. Given that SR is utilized during WNV outbreaks, continued work toward a complete risk assessment of the potential immunotoxic effects of SR is warranted. This would include parameterization of SR exposures with immunological consequences in wild birds using both replicating (in the laboratory) and non-replicating (in the field) antigens. As a start, this study indicates that SR can alter some immunological parameters, but with limited consequences to primary WNV infection outcome, and that elevated CORT mildly enhances SRs immunotoxicity in chickens.
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Synergized Resmethrin and corticosterone alter the chicken's response to west nile virus
Environmental Health Perspectives, 2009Co-Authors: Mark D. Jankowski, J. Christian Franson, Erich Möstl, Warren P. Porter, Erik K. HofmeisterAbstract:Debate concerning arbovirus control strategies remains contentious because concern regarding the relative risk of viral infection and environmental toxicant exposure is high but inadequately characterized. Taking this into account, mosquito control agencies employ aerial insecticides only after arbovirus surveillance data indicate high local mosquito-infection-rates. Successfully mitigating the risk of adult-mosquito-control insecticides ('adulticides') to non-target species such as humans, domestic animals, fish, beneficial insects and wildlife, while increasing their efficacy to reduce arbovirus outbreak intensity requires targeted scientific data from animal toxicity studies and environmental monitoring activities. Wild birds are an important reservoir host for WNv and are potentially exposed to insecticides used for mosquito control. However, no risk assessments have evaluated whether insecticides augment or extend the potential transmissibility of West Nile virus (WNv) in birds. In order to augment existing Resmethrin risk assessments, we aimed to determine whether synergized Resmethrin (SR) may cause chickens to develop an elevated or extended WN viremia and if subacute stress may affect its immunotoxicity. We distributed 40 chickens into four groups then exposed them prior to and during WNv infection with SR (50 {mu}g/l Resmethrin + 150 {mu}g/l piperonyl butoxide) and/or 20 mg/I corticosterone (CORT) in their drinking-water. Corticosterone was given for 10 continuous days and SR was given for 3 alternate days starting the 3rd day of CORT exposure, then chickens were subcutaneously inoculated with WNv on the 5th day of CORT treatment. Compared to controls, CORT treatment extended and elevated viremia, enhanced WNv-specific antibody and increased the percentage of birds that shed oral virus, whereas SR treatment extended viremia, depressed WNv-specific IgG, and increased the percentage of CORT-treated birds that shed oral virus. Corticosterone and SR independently and interactively altered immunity to WNv in chickens. Further characterization of how variations in SR-exposure to and CORT levels in chickens and wild birds relate to laboratory WNv-infection trials is warranted in order to place these findings into an epidemiological context.
Derek W Gammon - One of the best experts on this subject based on the ideXlab platform.
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Public safety aspects of pyrethroid insecticides used in West Nile virus-carrying mosquito control†
Pest management science, 2007Co-Authors: Derek W GammonAbstract:West Nile virus is becoming increasingly prevalent in the USA, causing fever, encephalitis, meningitis and many fatalities. Spread of the disease is reduced by controlling the mosquito vectors by a variety of means, including the use of pyrethroid insecticides, which are currently under scrutiny for potential carcinogenic effects in humans. Pyrethrins and Resmethrin, a pyrethroid, have been shown to cause tumours in rat and mouse models respectively. However, the tumours appear to be caused by liver enzyme induction and hypertrophy rather than genotoxicity, and the results are therefore unlikely to be applicable to humans. Nonetheless, for Resmethrin, the US Environmental Protection Agency (EPA) has concluded that there is a likely risk of carcinogenicity in humans, requiring the manufacturers to provide more detailed data to prove that it can be used safely in vector control. Reproductive toxicity of Resmethrin in the rat is also discussed.
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Perspective Public safety aspects of pyrethroid insecticides used in West Nile virus-carrying mosquito control
2007Co-Authors: Derek W GammonAbstract:West Nile virus is becoming increasingly prevalent in the USA, causing fever, encephalitis, meningitis and many fatalities. Spread of the disease is reduced by controlling the mosquito vectors by a variety of means, including the use of pyrethroid insecticides, which are currently under scrutiny for potential carcinogenic effects in humans. Pyrethrins and Resmethrin, a pyrethroid, have been shown to cause tumours in rat and mouse models respectively. However, the tumours appear to be caused by liver enzyme induction and hypertrophy rather than genotoxicity, and the results are therefore unlikely to be applicable to humans. Nonetheless, for Resmethrin, the US Environmental Protection Agency (EPA) has concluded that there is a likely risk of carcinogenicity in humans, requiring the manufacturers to provide more detailed data to prove that it can be used safely in vector control. Reproductive toxicity of Resmethrin in the rat is also discussed. 2007 Society of Chemical Industry
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A dietary risk assessment of the pyrethroid insecticide Resmethrin associated with its use for West Nile Virus mosquito vector control in California.
TheScientificWorldJournal, 2006Co-Authors: Wesley C. Carr, Poorni Iyer, Derek W GammonAbstract:An outbreak of human illnesses associated with West Nile Virus (WNV) occurred in New York City in 1999. Since then, it has gradually spread westwards, reaching northern California for the first time in 2005. WNV is transmitted by several mosquito species and birds serve as the main reservoir. Several control measures have been used, targeting both the aquatic larvae and the adult mosquitoes. In the latter case, roosting birds in trees are sprayed with pyrethroid insecticides because these are highly toxic to mosquitoes, but have low avian toxicity. A request was made to use a Resmethrin-containing insecticide during the month of October 2005 in California. Because Resmethrin was not registered for use on growing crops, concerns were raised about potential crop contamination. Therefore, an expedited dietary risk assessment was conducted on Resmethrin. Developmental toxicity in the rat (NOELs of 25 or 40 mg/kg/day) was used as the acute endpoint and dietary exposure was assessed using the DEEM-FCIDTM computer program. Only crops growing above ground during October were considered. Margins of Safety (MOS) were found to be above 100, the level generally considered to be sufficient to protect public health when using an animal NOEL.
Vivek Pokhrel - One of the best experts on this subject based on the ideXlab platform.
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Effects of truck-mounted, ultra low volume mosquito adulticides on honey bees (Apis mellifera) in a suburban field setting.
PloS one, 2018Co-Authors: Vivek Pokhrel, James A. Ottea, Nicholas Delisi, Robert G. Danka, Todd W. Walker, Kristen B. HealyAbstract:Few studies have examined the impact of mosquito adulticides on honey bees under conditions that reflect actual field exposure. Whereas several studies have evaluated the toxicity of mosquito control products on honey bees, most have been laboratory based and have focused solely on acute mortality as a measure of impact. The goal of this study was to determine effects of routine applications of truck-based ultra-low volume (ULV) mosquito adulticides (i.e., Scourge, Duet, and Deltagard) on honey bees in a suburban setting. The mosquito adulticides used in this study were pyrethroids with active ingredients Resmethrin (Scourge), prallethrin and sumithrin (Duet), and deltamethrin (Deltagard), in which Resmethrin, prallethrin, and sumithrin were synergized with piperonyl butoxide. We measured and compared mortality and detoxification enzyme activities (esterase and glutathione S-transferase) from sentinel beehives within and outside of mosquito control areas. Concurrently, colony health (i.e., number of adult bees, brood quantity and brood quality) was compared throughout the study period. No significant differences were observed in honey bee mortality, colony health or detoxification enzyme activities between treated (five sprayed areas each received one to three insecticide treatment) and control sites (four unsprayed areas that did not receive insecticide treatment) over the seven week study period. However, our laboratory study showed that exposure to Resmethrin, the active ingredient in Scourge, caused significant inhibition of esterase activity compared with the control group. Our findings suggest that proper application of truck based insecticides for mosquito control results in little or no exposure and therefore minimal effects on domestic honey bees.
Marc B Schenker - One of the best experts on this subject based on the ideXlab platform.
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pyrethroids in house dust from the homes of farm worker families in the micasa study
Environment International, 2013Co-Authors: Kelly J Trunnelle, Deborah H Bennett, Daniel J Tancredi, Maria T Stoecklinmarois, Tamara E Hennessyburt, Bruce D Hammock, Marc B SchenkerAbstract:article Indoorpesticide exposureisa growing concern,particularlyfor pyrethroids,a commonly used class of pesticides. Pyrethroid concentrations may be especially high in homes of immigrant farm worker families, who often live in close proximity to agricultural fields and are faced with poor housing conditions, potentially causing high pest infestation and pesticide use. We investigate levels of pyrethroids in the house dust of farm worker family homes in a study of mothers and children living in Mendota, CA, within the population-based Mexican Immigra- tiontoCalifornia:AgriculturalSafetyandAcculturation(MICASA)Study.Wepresentpesticideusedataandlevels of pyrethroid pesticides in indoor dust collected in 2009 as measured by questionnaires and a GC/MS analysis of the pyrethroids cis -a ndtrans-permethrin, cypermethrin, deltamethrin, esfenvalerate and Resmethrin in single dust samples collected from 55 households. Cis -a ndtrans-permethrin had the highest detection frequencies at 67%, with median concentrations of 244 and 172 ng/g dust, respectively. Cypermethrin was detected in 52% of the homes and had a median concentration of 186 ng/g dust. Esfenvalerate, Resmethrin and deltamethrin were detected in less than half the samples. We compared the pyrethroid concentrations found in our study to other studies looking at both rural and urban homes and daycares. Lower detection frequencies and/or lower median concentrations of cis -a ndtrans-permethrin and cypermethrin were observed in our study as compared to those studies. However, deltamethrin, esfenvalerate and Resmethrin were detected more frequently in the house dust from our study than in the other studies. Because households whose children had higher urinary pyrethroid metabolite levels were more likely to be analyzed in this study, a positive bias in our estimates of household pyrethroid levels may be expected. A positive association was observed with reported outdoor pesticide use and cypermethrin levels found in the indoor dust samples (rs = 0.28, p = 0.0450). There was also a positive association seen with summed pyrethroid levels inhouse dust and the results of a pesticide inventory conducted by field staff (rs =0 .32,p = 0.018), a potentially useful predictor of pesticide exposure in farm worker family homes. Further research is warranted to fully investigate the utility of such a measure.
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pyrethroids in house dust from the homes of farm worker families in the micasa study
Environment International, 2013Co-Authors: Kelly J Trunnelle, Deborah H Bennett, Daniel J Tancredi, Maria T Stoecklinmarois, Tamara E Hennessyburt, Bruce D Hammock, Shirley J Gee, Marc B SchenkerAbstract:article Indoorpesticide exposureisa growing concern,particularlyfor pyrethroids,a commonly used class of pesticides. Pyrethroid concentrations may be especially high in homes of immigrant farm worker families, who often live in close proximity to agricultural fields and are faced with poor housing conditions, potentially causing high pest infestation and pesticide use. We investigate levels of pyrethroids in the house dust of farm worker family homes in a study of mothers and children living in Mendota, CA, within the population-based Mexican Immigra- tiontoCalifornia:AgriculturalSafetyandAcculturation(MICASA)Study.Wepresentpesticideusedataandlevels of pyrethroid pesticides in indoor dust collected in 2009 as measured by questionnaires and a GC/MS analysis of the pyrethroids cis -a ndtrans-permethrin, cypermethrin, deltamethrin, esfenvalerate and Resmethrin in single dust samples collected from 55 households. Cis -a ndtrans-permethrin had the highest detection frequencies at 67%, with median concentrations of 244 and 172 ng/g dust, respectively. Cypermethrin was detected in 52% of the homes and had a median concentration of 186 ng/g dust. Esfenvalerate, Resmethrin and deltamethrin were detected in less than half the samples. We compared the pyrethroid concentrations found in our study to other studies looking at both rural and urban homes and daycares. Lower detection frequencies and/or lower median concentrations of cis -a ndtrans-permethrin and cypermethrin were observed in our study as compared to those studies. However, deltamethrin, esfenvalerate and Resmethrin were detected more frequently in the house dust from our study than in the other studies. Because households whose children had higher urinary pyrethroid metabolite levels were more likely to be analyzed in this study, a positive bias in our estimates of household pyrethroid levels may be expected. A positive association was observed with reported outdoor pesticide use and cypermethrin levels found in the indoor dust samples (rs = 0.28, p = 0.0450). There was also a positive association seen with summed pyrethroid levels inhouse dust and the results of a pesticide inventory conducted by field staff (rs =0 .32,p = 0.018), a potentially useful predictor of pesticide exposure in farm worker family homes. Further research is warranted to fully investigate the utility of such a measure.
