English

The pintail (Anas acuta) could be the latest addition to wildfowl conservation priorities after new figures from WWT and others show numbers have fallen by more than half since 2006. The findings are published in Waterbirds in the UK, the annual report of the Wetland Bird Survey, which counts all waterbirds on the UK’s major wetlands. Pintail is an elegant dabbling duck much loved by artists, including WWT founder Sir Peter Scott who named his daughter Dafila after its former scientific name. The recorded decline is especially worrying as up to half of all the pintail in northwest Europe rely on the UK’s estuaries and wetlands during winter. WWT’s Head of Species Monitoring, Richard Hearn, said: “Counts like the Wetland Bird Survey are our ‘canary in the cage’. Without them, we wouldn’t spot the risks till it was too late. The decline we’ve seen in pintail is ringing alarm bells. However, further research across its flyway could yet throw up more hopeful news. The key thing is that there’s still time to act.”

If you go down to the woods today, you may not be guaranteed to see too many birds but you could well bump into a census-taking birdwatcher. The Biological Records Centre celebrated its 50th anniversary this summer and citizen science flourishes in Britain as never before. If one needs proof, look no further than the proliferation of published bird atlases, in which every single scrap of data has been sourced from the fields and woods by volunteers and then donated freely to the atlas editors. The resulting books are among the most compelling statements of our nation’s amateur fixation with nature. Individual fieldworkers, monitoring their local birds in selected two-kilometre squares (known in atlas parlance as “tetrads”), have been able, because of new data-processing software, to contribute to the national overview and to the finer-grain regional picture. Between them, the tens of thousands of observers have assembled an astonishing 19 million records. In the process, they have made Britain’s birds the most thoroughly documented avifauna on the planet. Yet the story they reveal is deeply troubling. Never before have we known in so much detail how badly some of our birds are faring. The grey partridge, which was once found nationwide and whose overall numbers were calculated in seven figures, has sunk towards national extinction. Today, there may be fewer than 75,000 pairs and the decline continues.

There are numerous concerns regarding the neurotoxicity of contaminated air inside pressurized aircraft. Neurological symptoms have been seen in many aircrew personnel who have reportedly been exposed to the potentially toxic breathable air in airliners. Symptoms, allegedly contracted by aircrew and passengers, are thought to be caused by a single large exposure or repetitive cumulative low-level exposures to toxic chemicals in the airliner internal air. Genetic variation plays a rôle. We report here the case of a 43-year old airline pilot who presented with neurological deficits and other symptoms. The pilot died without regaining good health. In vivo blood had been collected ante mortem. Analysis of the serum confirmed grossly elevated levels of serum autoantibody biomarkers for neuronal cell degeneration compared with a control group. At autopsy, various tissues underwent histopathological assessment. Brain and spinal tissues exhibited axonal degeneration and demyelination. Peripheral nerves showed T-lymphocyte infiltration and demyelination. T lymphocytes had infiltrated the heart muscle tissue. The post-mortem tests and pathological examination of the nervous system confirm the autoantibody biomarker results. Differential diagnosis showed that the work environment, clinical condition, histopathology and serum biomarkers for nervous system injury are consistent with organophosphate-induced neurotoxicity. The results also showed that exposure to organophosphates rendered the nervous system and heart tissue sensitive and predisposed to further injury.

The objective of the present study was to evaluate immunotoxic effects of imidacloprid in female BALB/c mice. Imidacloprid was administered orally daily at 10, 5, or 2.5 mg/kg over 28 days. Specific parameters of humoral and cellular immune response including hemagglutinating antibody (HA) titer to sheep red blood cells (SRBC; T-dependent antigen), delayed type hypersensitivity (DTH) response to SRBC, and T-lymphocyte proliferation in response to phytohemagglutinin (PHA) were evaluated. The results showed that imidacloprid at high dose, specifically suppressed cell-mediated immune response as was evident from decreased DTH response and decreased stimulation index of T-lymphocytes to PHA. At this dose, there were also prominent histopathological alterations in spleen and liver. Histopathological analysis of footpad sections of mice revealed dose-related suppression of DTH response. Imidacloprid at low dose of 2.5 mg/kg/day did not produce any significant alterations in cellular and humoral immune response and it seemed to be an appropriate dose for assessment of ‘no observable adverse effects level’ for immunotoxicity in BALB/c mice. The results also indicated that imidacloprid has immunosuppressive effects at doses >5 mg/kg, which could potentially be attributed to direct cytotoxic effects of IMD against T cells (particularly TH cells) and that long-term exposure could be detrimental to the immune system.

Neonicotinoids are the most widely used insecticides in the world. They are toxic to most arthropods. They are widely applied as seed dressings because they act systemically, protecting all parts of the crop. Neonicotinoids can persist and accumulate in soils. They leach into waterways. They are found in nectar and pollen of treated crops. Concentrations in soils, waterways, field margin plants, nectar and pollen have commonly been found to be levels sufficient to control crop pests; they commonly exceed the LC50 (the concentration which kills 50% of individuals) for beneficial organisms. There have been many studies in the lab and, increasingly, in combinations of lab and field conditions on the possible impacts of neonicotinoids on both honey bees and bumble bees. They indicate that concentrations in nectar and pollen in crops are not lethal to bees but are sometimes sufficient to reduce their ability to learn, to forage and to find their way back to the hive. There is evidence that they can reduce the survival of colonies. The general conclusion of these studies is that, together with such things as loss of flower-rich habitat and Varroa mite, neonicotinoid use may have caused losses of bee populations. The manufacturers say that only studies carried out entirely in the field are valid. This is a curious reversal of arguments in respect of the impact of organochlorine pesticides on birds in the 1960s, when manufacturers said field studies were of no value and that all effects had to be demonstrated in the lab.