Colin Prescott

• PhD
• Professor (Associate) at University of Reading

1. Further to earlier reports in this series, a total of 122 rodent tissue samples were received for DNA sequencing at the laboratories of the Animal and Plant Health Agency (APHA) during the period August 2022 to July 2023. Among these, 22 samples did not yield DNA material that could be sequenced. Of the remaining 100 samples, 95 were of Norway r...

Rice agriculture provides wetlands and complex habitats supporting biodiversity. Wetlands associated with rice agriculture since the 1960s have increased by 32% and now form nearly 12% of wetlands globally at a time when vast areas of natural wetlands are being lost. In this chapter, we set our sights beyond Sustainable Development Goal (SDG) 2 tha...

1. During the period 2009 and 2022, in which these DNA resistance surveys have been conducted, first at the University of Reading and now at the Animal and Plant Health Agency, a total of 489 Norway rat and 129 house mouse tissue samples have been examined and DNA has been extracted from them and sequenced. Among these samples we found that 77.9% o...

The presentation describes the main Norway rat and house mouse resistance mutations and their geographical distributions in the United Kingdom. It introduces the term 'hybrid resistance', describes the biogeographical processes that probably lead to its development and where it is presently found in UK rats and mice. The first occurrence of the 'sp...

Background The house mouse (Mus musculus) is a globally distributed rodent pest species against which anticoagulant rodenticides are widely used for the protection of human and animal health and the conservation of threatened wildlife. Anticoagulant‐resistant house mice have been known for more than half a century. A house mouse strain was develope...

Abstract Background The house mouse (Mus musculus) is a globally distributed rodent pest species against which anticoagulant rodenticides are widely used for the protection of human and animal health and the conservation of threatened wildlife. Anticoagulant-resistant house mice have been known for more than half a century. A house mouse strain was...

Anticoagulant resistance management and house mouse (Mus musculus)

Anticoagulant resistance in the Norway rat IRattus norvegicus)

SUMMARY 1. New resistance data are presented for tissue samples from Norway rats (Rattus norvegicus) and house mice (Mus musculus) collected in the period September 2019 to February 2020. Coronavirus restrictions at the University of Reading prevented laboratory work after that date. Once again, efforts were made to obtain samples in geographical a...

A review of the breeding performance of barn owls from five regions of the UK

Anticoagulant resistance has been present in Norway rats (Rattus norvegicus) in Hampshire and Berkshire for forty years. All first-generation anticoagulants and two of the second generation, bromadiolone and difenacoum, are resisted by rats carrying the L120Q single nucleotide polymorphism (SNP). A regulatory restriction on the use of resistance-br...

Data on the breeding of the barn owl, Tyto alba, in five regions of the UK during the 2018 breeding season

Report describes breeding parameters of the barn owl, Tyto alba, in five regions on UK during the 2018 breeding season.

SUMMARY 1. New resistance data are presented for tissue samples from Norway rats (Rattus norvegicus) and house mice (Mus musculus) collected in the period September 2018 to September 2019. Particular efforts were made to obtain samples in geographical areas in the UK from which none had been collected in the past. 2. A total of 140 Norway rat tiss...

SUMMARY 1. The status of anticoagulant resistance in the UK is unique in several ways. Most importantly, more than fifty years of continuous research into this phenomenon, both in Norway rats and house mice, has provided an extensive platform of knowledge upon which to base practical advice on anticoagulant use and recommendations on resistance ma...

The main differences between this revision and the earlier version are: • this version includes advice after the HSE decision to allow brodifacoum, flocoumafen and difethialone to be used outdoors. • it has some advice to those who are trying to decide between ‘normal’ strength products and the low-strength ones that are coming to the market. • it...

While resistance to anticoagulant rodenticides is known to occur in many European populations of Norway rat and house mouse, to-date no data is available on the occurrence in Ireland of such resistance. No genetic evidence for the occurrence of resistance was found in 65 Norway rat samples analysed, indicative of an absence, or low prevalence, of r...

Control of commensal rodents worldwide relies on the use of rodenticides. In Europe, mostly anticoagulants are available. First generation anticoagulants were developed in the late 1950s’. Their use resulted in the selection of resistant strains of rats and mice. As a consequence, second generation anticoagulants were developed, more potent but als...

Anticoagulant rodenticides are potent vertebrate poisons and can only be used safely in conjunction with a range of necessary risk mitigation measures. Many measures are obvious and widely applied, such as the addition of a human taste deterrent in bait formulations, the collection and safe disposal of poisoned rodents and the use of tamper-resista...

1.1 The Government Oversight Group (GOG), chaired by the Health and Safety Executive (HSE), has determined that the work undertaken by Campaign for Responsible Rodenticide Use (CRRU) UK and its stakeholder partners to establish the UK Rodenticide Stewardship Regime has met the government ‘high level principles’ for rodenticide stewardship (GOG 2017...

Abstract The UK Rodenticide Stewardship Regime has been implemented to promote the nation-wide adoption of best practice in rodent pest management, in particular the use of the second-generation anticoagulants (SGARs) by professionals. The main objective of the regime is to minimize exposure of non-target wildlife to these substances and, thereby,...

1. The status of anticoagulant resistance in the UK is unique in several ways. Most importantly, more than fifty years of continuous research into this phenomenon, both in Norway rats and house mice, has provided an extensive platform of knowledge upon which to base practical advice on anticoagulant use and recommendations on resistance management....

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Presentation in Invited Paper Session on Rodents

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1. The UK Rodenticide Stewardship Regime was in place when the first products with ‘stewardship conditions’ labels came to the market in April 2016. This was facilitated by the following actions by six CRRU UK stewardship implementation work groups: i. The Best Practice Work Group (BPWG) published a code of best practice for rodent pest management...

Little is known about native and non-native rodent species interactions in complex tropical agro-ecosystems. We hypothesised that the native non-pest rodent Rattus everetti may be competitively dominant over the invasive pest rodent Rattus tanezumi within agroforests. We tested this experimentally by using pulse removal for three consecutive months...

This updated 2nd edition, two decades after the publication of the first edition, combines information from the latest scientific research on rodent pests and their control. It includes 19 chapters discussing: the natural history of rodents and preadaptations to pestilence; commensal rodents; rodents in agriculture and forestry; rodents as carriers...

Seychelles supports around three million nesting pairs of sooty terns but there have been recent declines and the colonies continue to face actual threats of habitat change and excessive commercial harvesting of their eggs, and potential threats caused by commercial fishing and climate change. A possible method to counter these threats is to re-est...

Context Rattus tanezumi (the Asian house rat) is the principal rodent pest of rice and coconut crops in the Philippines. Little is known about the population and breeding ecology of R. tanezumi in complex agroecosystems; thus, current methods of rodent control may be inappropriate or poorly implemented. Aims To investigate the habitat use, populat...

Context. Rattus tanezumi (the Asian house rat) is the principal rodent pest of rice and coconut crops in the Philippines. Little is known about the population and breeding ecology of R. tanezumi in complex agroecosystems; thus, current methods of rodent control may be inappropriate or poorly implemented. Aims. To investigate the habitat use, popula...

Seychelles supports around three million nesting pairs of sooty terns. However, there have been recent declines and the colonies continue to face ongoing threats from habitat change and excessive commercial harvesting of their eggs, as well as potential threats by commercial fishing and climate change. A possible method to counter these threats is...

Little quantitative information is available on the efficacy of measures to mitigate non-target impacts of the second-generation anticoagulants (SGARS) but four UK monitoring schemes, operated over the last 30 years and each with a different objective, permit some conclusions to be drawn. The Pesticide Usage Survey estimated quantities of anticoagu...

The Biocidal Products Directive (98/8 CE) has been implemented to evaluate the safety and efficacy of products used in households and industry and other buildings to control pests. Rodenticides were the first products to be evaluated and active substances were reviewed, evaluated and eventually registered. In a second step, commercial products were...

Rice crops are globally important for food security, with over 90% of the world's rice produced in Asia. However, in many Asian rice growing areas, water shortages are a major constraint to rice production. To address this issue, management techniques have been developed to produce rice with less water. One such method is Alternate Wetting and Dryi...

Reduction of vegetation height is recommended as a management strategy for controlling rodent pests of rice in Southeast Asia, but there are limited field data to assess its effectiveness. The breeding biology of the main pest species of rodent in the Philippines, Rattus tanezumi, suggests that habitat manipulation in irrigated rice-coconut croppin...

The climatic and geographic range of Asia provides ideal conditions for growing rice. With a growing demand for food security to feed an ever increasing human population, there is growing pressure to increase rice production. Within the Philippines, rice fields cover over 2.6 million ha and provide habitat for at least 50 species of waterbirds. Thu...

Anticoagulants rodenticides have already known for over half a century, as effective and safe method of rodent control. However, discovered in 1958 anticoagulant resistance has given us a very important problem for their future long-term use. Laboratory tests provide the main method for identification the different types of anticoagulant resistance...

BACKGROUND: The tyrosine to cysteine amino acid substitution at location 139 of the vkorc1 protein (i.e. tyrosine139cysteine or Y139C) is the most widespread anticoagulant resistance mutation in Norway rats (Rattus norvegicus Berk.) in Europe. Field trials were conducted to determine the incidence of the Y139C mutation at two rat-infested farms in...

Context Rattus tanezumi is a serious crop pest within the island of Luzon, Philippines. In intensive flood-irrigated rice field ecosystems of Luzon, female R. tanezumi are known to primarily nest within the tillers of ripening rice fields and along the banks of irrigation canals. The nesting habits of R. tanezumi in complex rice–coconut cropping sy...

Post-registration impacts of pesticides in the UK are monitored by the Wildlife Incident Investigation Scheme (WIIS) [1]. The scheme has been operated by government scientists since 1985 and, since 1993, reports have been published with information on individual incidents. Incidents involving both wildlife and companion animals are recorded. Verteb...

The use of potent anticogulant rodenticide ‘resistance-breakers’ is avoided due to their higher toxicity and potential to be more hazardous in the environment [6]. However, in areas where practitioners seek to control resistant rodent infestations, their use may pose less of a risk than applications of ineffective baits. Compounds to which rodents...

Anticoagulant rodenticide (AR) resistance in Norway rat populations has been a problem for fifty years, however its impact on non-target species, particularly predatory and scavenging animals has received little attention. Field trials were conducted on farms in Germany and England where resistance to anticoagulant rodenticides had been confirmed....

In the UK, Campylobacter spp. and Lymphocytic Choriomeningitis Virus (LCMV), an Old World arenavirus, cause two zoonoses of concern that may be transmissible from rodents to humans and livestock. The aims of this preliminary investigation were to examine the occurrence of Campylobacter spp. and LCMV in Norway rats Rattus norvegicus on UK farms and...

In the UK, Campylobacter spp. and Lymphocytic Choriomeningitis Virus (LCMV), an Old World arenavirus, cause two zoonoses of concern that may be transmissible from rodents to humans and livestock. The aims of this preliminary investigation were to examine the occurrence of Campylobacter spp. and LCMV in Norway rats Rattus norvegicus on UK farms and...

Anticoagulant rodenticide (AR) resistance in Norway rat populations has been a problem for fifty years, however its impact on non-target species, particularly predatory and scavenging animals has received little attention. Field trials were conducted on farms in Germany and England where resistance to anticoagulant rodenticides had been confirmed....

In the lowland agro-forest of the Sierra Madre Biodiversity Corridor (SMBC), it is considered that a native rodent species, Rattus everetti is competitively dominant over an invasive pest species, Rattus tanezumi. The main aim of this study was to assess the response of R. tanezumi following short term removal of R. everetti. We tested this experim...

The University of Reading has conducted some preliminary work on the prevalence of Campylobacter spp., Salmonella spp. and Arenavirus in Norway rats trapped from farms and semi-urban areas in central southern England. Campylobacter is the cause of a notificable disease in the UK, with 57,772 cases reported for England and Wales in 2009. Transmissio...

A survey of the knowledge, attitudes and practices (KAP) of 100 rice farmers and 50 coconut farmers was conducted in the coastal lowland agro-ecosystems of the Sierra Madre Biodiversity Corridor, Luzon, Philippines to identify current rodent management practices and to understand the extent of rat damage and the attitudes of farmers to community ac...

A sample of 10 Norway rats (Rattus norvegicus) was taken for DNA resistance testing from an agricultural site in Kent where applications of the anticoagulant rodenticide bromadiolone had been unsuccessful. All animals tested were homozygous for the single nucleotide VKORC1 polymorphism tyrosine139phenylalanine, or Y139F. This is a common resistance...

We compared the quantity of wheat bait consumed by Norway rats (Rattus norvegicus) from: (i) wooden bait trays, made as safe as possible from non-target animals using materials available at trial sites, and (ii) three different, proprietary tamper-resistant rat bait boxes. A balanced Latin square experimental design was used to overcome operational...

This paper presents a reappraisal of the blood clotting response (BCR) tests for anticoagulant rodenticides, and proposes a standardised methodology for identifying and quantifying physiological resistance in populations of rodent species. The standardisation is based on the International Normalised Ratio, which is standardised against a WHO intern...

A new blood clotting response test was used to determine the susceptibility, to coumatetralyl and bromadiolone, of laboratory strains of Norway rat from Germany and the UK (Hampshire), and wild rats trapped on farms in Wales (UK) and Westphalia (Germany). Resistance factors were calculated in relation to the CD strain of Norway rat. An outbred stra...

We investigated the relationship between the severity and incidence of resistance among Norway rats (Rattus norvegicus) on a farm in Wales and the subsequent outcome of a practical rodent control operation. Bromadiolone resistance factors were estimated for rats trapped on the farm using the blood clotting response test, and were found to be 2 to 3...

We investigated the species diversity and habitat use of rodents in the Ifugao Rice Terraces (IRT), Luzon, Philippines, as a first step in their assessment either as pest species of rice or as potential non-target species of rodent control practice. Trapping was carried out in caneland and forest habitats adjacent to rice cropland using trap lines...

The efficacy of a 0.025% warfarin formulation against the lesser bandicoot rat (Bandicola bengalensis) was evaluated in groundnut and wheat crops in district Chakwal of the Pothwar Plateau, Pakistan. The baiting was started at early flowering stages of the respective crops using a broken rice formula (with additives) by placing bait stations near a...

Anticoagulant compounds, i.e., derivatives of either 4-hydroxycoumarin (e.g., warfarin, bromadiolone) or indane-1,3-dione (e.g., diphacinone, chlorophacinone), have been in worldwide use as rodenticides for >50 years. These compounds inhibit blood coagulation by repression of the vitamin K reductase reaction (VKOR). Anticoagulant-resistant rodent p...

The European Commission’s Biocidal Products Directive (Council Directive 98/8 EC), known as the BPD, is the largest regulatory exercise ever to affect the urban pest control industry. Although focussed in the European Union its impact is global because any company selling pest control products in the EU must follow its principles. All active substa...

Warfarin is a first generation anticoagulant that relies on multiple feeding events to achieve lethality in susceptible rodents. For the Bandicoot rat, warfarin susceptibility baselines were established using the lethal feeding period (LFP) test methodology. Against a 0.003% warfarin formulation, LFP50 values of 2 and 4 days, and LFP99 values of 16...

Blood clotting response (BCR) resistance tests are available for a number of anticoagulant rodenticides. However, during the development of these tests many of the test parameters have been changed, making meaningful comparisons between results difficult. It was recognised that a standard methodology was urgently required for future BCR resistance...

Resistance baselines were obtained for the first generation anticoagulant rodenticides chlorophacinone and diphacinone using laboratory, caesarian-derived Norway rats (Rattus norvegicus) as the susceptible strain and the blood clotting response test method. The ED99 estimates for a quantal response were: chlorophacinone, males 0.86 mg kg−1, females...

Rats and mice have traditionally been considered one of the most important pests of sugarcane. However, "control" campaigns are rarely specific to the target species, and can have an affect on local wildlife, in particular nonpest rodent species. The objective of this study was to distinguish between rodent species that are pests and those that are...

A wild house mouse (Mus domesticus) population originally trapped near Reading, Berkshire, United Kingdom, and maintained as a colony in the laboratory, was subjected to the discriminating feeding period of the warfarin resistance test, as used by Wallace and MacSwiney (1976) and derived from the work of Rowe and Redfern (1964). Eighty percent of t...

For the first time, it has been unequivocally shown that multiple-feed second-generation anticoagulant rodenticides were ineffective against a population of rats in N.W. Berkshire, UK because of an unusually high prevalence and high degree of resistance. Use of the non-anticoagulant rodenticide calciferol led to a substantial reduction in the popul...

Warfarin resistance was first discovered among Norway rat (Rattus norvegicus) populations in Scotland in 1958 and further reports of resistance, both in this species and in others, soon followed from other parts of Europe and the United States. Researchers quickly defined the practical impact of these resistance phenomena and developed robust metho...

Rodenticides with delayed action are generally more effective than fast-acting compounds because of the phenomenon of bait shyness. Calciferols have a stop-feed effect quite soon after dosing, and physiological effects are measurable within one day of dosing. We investigated whether bait shyness might result from these fairly rapid effects in the l...

Cost effective methods are now available to identify physiological resistance in wild populations of Norway rat and House mice that are proving difficult to control. The new molecular methodology is a significant development for resistance management.