A health warning has been issued by the Forestry Commission of Scotland and England over the recent invasion of toxic caterpillars known as the oak processionary moth (OPM).

OPM caterpillars were spotted emerging from eggs in mid-April, with the largest infestations occurring in and around Greater London. Originating in southern Europe, these caterpillars are not native to England, but were accidentally imported in 2005.

The OPM caterpillar has over 62,000 long, white hairs on its body that contain thaumetopoein, an irritating protein that can trigger mild to serious allergic reactions, asthma attacks, breathing difficulties, skin rashes, and vomiting in humans. These hairs can be released as a defense mechanism, and the protein contained within can remain active for up to five years. As such, people are wondering what kind of public health threat this invasive species actually poses.

The biggest concern is the potential for airborne transmission of the hairs before and after these species have completed a full lifecycle. More specifically, airborne transmission poses an increased risk to asthma sufferers, a population estimated by GlobalData epidemiologists to be approximately 10 million in the UK. These individuals can experience a fatal asthmatic attack if exposed. While the Forestry Commission will continue treating trees with biopesticides until early June and manually destroy larger nests, the dispersal of OPM caterpillar hairs continues to be a cause for concern.

By July or August, the caterpillars will have morphed into full-grown moths and die within two days. However, spikes in OPM-related morbidity may continue to be observed as a result of exposure to the toxic caterpillar hairs. Although this is not a major epidemic, the public should remain vigilant of infestation hotspots when venturing outdoors, and public health agencies should continue to monitor OPM-related cases and treat affected areas to contain the current outbreak.

For more insight and data, visit the GlobalData Report Store – Hospital Management is part of GlobalData Plc.

Related Reports

GlobalData (2014). EpiCast Report: Asthma – Epidemiology Forecast to 2023, September 2014, GDHCER024-14