Trends in de-lousing of Norwegian farmed salmon from 2000-2019-Consumption of medicines, salmon louse resistance and non-medicinal control methods

The salmon louse Lepeophtheirus salmonis has been a substantial obstacle in Norwegian farming of Atlantic salmon for decades. With a limited selection of available medicines and frequent delousing treatments, resistance has emerged among salmon lice. Surveillance of salmon louse sensitivity has been in place since 2013, and consumption of medicines has been recorded since the early 80’s. The peak year for salmon lice treatments was 2015, when 5.7 times as many tonnes of salmonids were treated compared to harvested. In recent years, non-medicinal methods of delousing farmed fish have been introduced to the industry. By utilizing data on the annual consumption of medicines, annual frequency of medicinal and non-medicinal treatments, the aim of the current study was to describe the causative factors behind salmon lice sensitivity in the years 2000–2019, measured through toxicity tests–bioassays. The sensitivity data from 2000–2012 demonstrate the early emergence of resistance in salmon lice along the Norwegian coast. Reduced sensitivity towards azamethiphos, deltamethrin and emamectin benzoate was evident from 2009, 2009 and 2007, respectively. The annual variation in medicine consumption and frequency of medicinal treatments correlated well with the evolution in salmon louse sensitivity. The patterns are similar, with a relatively small response delay from the decline in the consumption of medicines in Norway (2016 and onward) to the decline in measured resistance among salmon louse (2017 and onward). 2017 was the first year in which non-medicinal treatments outnumbered medicinal delousing treatments as well as the peak year in numbers of cleanerfish deployed. This study highlights the significance of avoiding heavy reliance on a few substance groups to combat ectoparasites, this can be a potent catalyst for resistance evolution. Further, it demonstrates the importance of transparency in the global industry, which enables the industry to learn from poor choices in the past.

Chronic pesticide mixture exposure including paraquat and respiratory outcomes among Colombian farmers

This study explored the potential association between chronic exposure to pesticide mixtures including paraquat and respiratory outcomes among Colombian farmers. Sociodemographic and occupational data, respiratory symptoms and spirometric data were collected. Paraquat in spot urine samples were quantified with solid-phase extraction high-performance liquid chromatography. Multiple Poisson regressions with robust variance were used to determine factors associated with respiratory outcomes. Profiles of pesticide mixtures used were identified among 217 farmworkers, but profenofos and methamidophos-based mixtures were more frequent. Chronic paraquat exposure was slightly associated with self-reported asthma (PR: 1.06; 95% CI 1.00 to 1.13). Different pesticide mixtures were associated with flu, thoracic pain, allergic rhinitis, and obstructive pattern in spirometry. Although acute exposure to paraquat is low among Colombian farmers participating in the study, associations between respiratory outcomes and chronic pesticide mixtures exposure including profenofos, methamidophos or glyphosate require further specific studies.

Relationship between alcohol co-ingestion and outcome in profenofos self-poisoning - A prospective case series

INTRODUCTION

The importance of alcohol co-ingestion for outcome in organophosphorus (OP) insecticide self-poisoning has only been studied for the relatively hydrophilic dimethyl insecticide, dimethoate. We aimed to assess the effect of alcohol in acute poisoning with the lipophilic S-alkyl OP insecticide, profenofos.

METHODOLOGY

Demographic and clinical data, including an alcohol history, were prospectively collected from all cases of acute poisoning with agricultural profenofos EC50 presenting to two Sri Lankan hospitals over seven years.

RESULTS

Of 1859 patients with acute OP insecticide self-poisoning, 243 (13.1%) reported ingestion of profenofos (male 182/243, 74.9%). Alcohol co-ingestion was reported by 64/243 (26.3%). All patients reporting alcohol co-ingestion were male (64/64 [100%] vs 118/179 [65.9%] not reporting alcohol ingestion, p<0.001). More patients reporting alcohol co-ingestion died (10/64 [15.6%] vs 10/179 [5.6%]; p = 0.013) and required intubation (13/64 [20.3%] vs 16/179 [8.9%], p = 0.016) compared to those who did not co-ingest alcohol. Using multi-logistic regression, controlling for the estimated dose ingested, age (OR 11.1 [2.5 to 48.9] for age > 35 years vs ≤35 years) and alcohol co-ingestion (OR 3.1 [1.2 to 7.9]) were independently associated with increased risk of death. Increased risk of intubation was independently associated with age (OR 3.2 [1.6 to 6.6] for age > 35 years vs ≤35 years) and alcohol co-ingestion (OR 3.2 [1.6 to 6.4]).

CONCLUSION

A history of alcohol co-ingestion, as well as older age, is independently associated with worse outcome in patients' self-poisoned with profenofos.

[Studying chronic effects caused by alkaline products of from bituminous-salt masses obtained through destruction of sarin, soman and RVX]

The authors summarized study results on chronic effects caused by products of leaching from bituminous-salt masses obtained through destruction of sarin, soman and RVX. State of experimental rats was evaluated with integral informative tests (physiologic, biochemical, hematologic and morphologic) presenting changes in objective health parameters and revealing every disorder in organs and systems functioning.

Impact of triazophos insecticide on paddy soil environment

A laboratory incubation study was carried out to elucidate the dynamic response of insecticide (triazophos) on a paddy field soil health under controlled moisture (flooded soil) and temperature (25 degrees C). The insecticide was applied at five levels that were 0.0 (control), 0.5 field rate (FR), 1.0 FR, 5.0 FR, and 10.0 FR, where FR was 1500 ml/hm2, and the parameters were studied at 1, 4, 7, 14, and 21 days after treatments' addition. The electron transport system (ETS)/dehydrogenase activity exhibited a negative correlation with insecticide concentrations, and the activity affected adversely as the concentration increased. The higher doses of 5 and 10 field rates significantly reduced the ETS activity, while lower rates failed to produce any significant inhibiting effect against the control. The toxicity of insecticide decreased towards decreasing the ETS activity with the advancement of incubation period. The insecticide caused an improvement in the soil phenol content and it increased with increasing concentration of insecticide. The insecticide incorporation applied at various concentrations did not produce any significant change in soil protein content and it remained stable throughout the incubation period of 21-days. The response of biomass phospholipid content was nearly similar to ETS activity. The phospholipid content was decreased with the addition of insecticide and the toxicity was in the order: 10 FR (field rate) > 5 FR > 1.0 FR > 0.5 FR > control and it also decreased with incubation period.

Elucidation of tumor-promoting potential of a combination pesticide by short-term, in vivo bioassay

The use of combination pesticide (profenofos 40% + cypermethrin 4% EC) is on the rise in India and elsewhere. Cypermethrin is reported to be a tumor promoter, but its tumor-promoting potential along with profenofos is yet to be studied. A short-term, in vivo test for detection of a tumor promoter is cost-effective, saves time, and requires fewer animals than conventional methods. We report on a short-term test based on mechanisms of significant importance in tumor promotion. In this study, we have tested the tumor-promoting potential of a combination pesticide containing profenofos 40% and cypermethrin 4% EC in Wistar rats. Although cypermethrin has been reported as a tumor promoter, our study shows that the combination pesticide containing profenofos 40% and cypermethrin 4% EC is not a tumor promoter.

The health status of northern Omo State Farm workers exposed to chlorpyrifos and profenofos

The health effects of organophosphorus (OP) pesticides on cholinesterase (ChE) activities were assessed among 81 pest control workers from Northern Omo State Farm (Ethiopia), following the occupational use of Chlorpyrifos 25 and 48% ULV and Profenifos 250 EC/ULV. Plasma ChE (PChE) and erythrocyte ChE (AChE) activities were determined electrometrically before and after pesticide exposure. Plasma alkaline phosphatase (AP) and glutamic pyruvic transaminase (GPT) values were estimated colorimetrically. Risk factors of pesticide poisoning and related occupational factors were assessed following the WHO recommendations. The mean PChE and AChE activities determined after pesticide exposures were significantly lower than the pre-exposure values (P < 0.05); 16% and 40% of the pest control workers had PChE and AChE levels below 50% of the pre-exposure values, respectively. The mean plasma AP and GPT values were found to be within the recommended normal limits. No significant difference in either of the ChE activities was observed between the spray men and the pest assessors, although the former were believed to have frequent contact with the concentrated OP formulations. Risk factors of pesticide poisoning such as workers ignorance about the toxicity of pesticides, poor personal hygiene and total absence or improper use of personal protective devices were prevalent. Measures that should be considered to minimize the problem in the farm population are recommended.

Mortality following cotton defoliation: San Joaquin Valley, California, 1970-1990

A proportional mortality study comparing the cotton-growing areas of the San Joaquin Valley with the rest of the State of California was performed by the Office of Environmental Health Hazard Assessment as a continuation of earlier studies related to mercaptan-releasing pesticides. This mortality study found a pattern of increased proportion of "respiratory causes" mortality (ICD codes 460-519), statistically significant at less than the .05 probability level, for 15 of 21 years between 1970 and 1990, for the time period during and immediately following cotton defoliation. Defoliants which have the potential to produce acute symptoms include DEF and Folex, both of which release odorous butyl mercaptan gas as a degradation product. This paper tests the hypothesis that exposure to cotton defoliant breakdown products may be associated with a disproportionate increase in mortality. Prediction of the mortality proportions by pounds of DEF and Folex used was not statistically significant in the unadjusted models or in models adjusted for air pollution variables. One air pollution adjustment factor, total suspended particulates, was a statistically significant independent mortality proportion predictor. This finding suggests that total suspended particulates, not defoliants, may be related to mortality differentials during defoliation season. Possible confounding by demographic variation of the counties was not controlled in the analysis.

Acute health effects from community exposure to N-propyl mercaptan from an ethoprop (Mocap)-treated potato field in Siskiyou County, California

A 145-acre potato field adjacent to Dorris, California, was treated with ethoprop (Mocap) to control nematodes. Ethoprop releases n-propyl mercaptan, a highly odorous and volatile gas, as a degradation product of the pesticide. An epidemiological investigation was undertaken by the California Department of Health Services because community residents sought medical attention for odor-related illness. Elevated health effects were found among those who reported smelling a strong odor (n-propyl mercaptan has a characteristic onion-like odor). In a logistic regression analysis, the most highly elevated 6-wk health effect incidence risks, expressed as odds ratios (ORs) adjusted for age, sex, and current cigarette smoking status, were for headache (OR = 5.08), diarrhea (OR = 3.80), runny nose (OR = 5.31), sore throat (OR = 3.58), burning/itching eyes (OR = 5.64), fever (OR = 3.59), hay fever attacks (OR = 3.50), and asthma attacks (OR = 6.0). Based upon these elevated health effects, it is recommended that human exposures to n-propyl mercaptan be minimized to the extent practicable.

Presumptive organophosphate-induced delayed neurotoxicity in a paralyzed bull

A case of presumptive organophosphate-induced delayed neurotoxicity in a bull is described. All signs were referable to a focal cervical or diffuse spinal cord lesion. These included recumbency with severe symmetrical paresis of all 4 limbs, the hind limb involvement being greater than the forelimbs. CSF analysis was normal. The bull was killed and necropsied. There were no gross CNS lesions. Histopathologic finds are characterized and their resemblance to lesions observed in delayed neurotoxicity caused by organophosphate compounds is discussed. The bull had been treated with organophosphate insecticide (famphur) 43 days prior to the onset of signs.