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Issues for Pest Management. Issues for Pest Management. Dr Stephen Battersby President, CIEH. Summary. Health risks from rodents EU & the Biocidal Products Directive (BPD) Resistance & second generation anti-coagulants Other pests, e.g. bedbugs
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Issues for Pest Management Dr Stephen Battersby President, CIEH
Summary • Health risks from rodents • EU & the Biocidal Products Directive (BPD) • Resistance & second generation anti-coagulants • Other pests, e.g. bedbugs • Public sector cuts and pest control services • Climate change and vector control
Rodents and public health • It has been suggested that mice are merely a nuisance pest – that is not so • WHO Publication “Public Health Significance of Urban Pests “ - mice “should be treated as a potential threat to public health” • Rat infestations in urban areas also a symptom of a degraded environment
Summary of diseases associated with rodents (primarily Rattus spp and Mus spp) a Indicates zoonoses of both house mice and Rattus spp.;
Summary of diseases associated with rodents (primarily Rattus spp and Mus spp), 2
Summary of diseases associated with rodents (primarily Rattus spp and Mus spp), 3
Summary of diseases associated with rodents (primarily Rattus spp and Mus spp), 4 b Indicates zoonosis only of house mice Mus musculis
Examples of pathogens that may be transmitted by rodents & risk NB. This is a global assessment. Based on: Meerburg BG, Singleton GR, & Kijlstra A, 2009,Rodent-borne diseases and their risks for public health,Critical Reviews in Microbiology, 2009; 35(3): 221–270
Hantavirus • In Baltimore USA, Hantavirus antibody prevalence rates of 50%+ have been found • (See: Easterbrook JD, Shields, T Klein SL & Glass GE, Vector Borne Zoonotic Dis. 2005 Fall;5(3):296-9: Yanagihara R, Rev Infect Dis 1990 May Jun;12(3):449-57R: and Childs JE, Korch GW, Glass GE, LeDuc JW, Shah KVAm J Epidemiol. 1987 Jul;126(1):55-68. for example) • Humans are the only known disease end point of the infection.
Buenos Aires Study • 10 sites sampled & 151 R.norvegicus trapped • Hantavirus seroprevalence was 11.9% varying between 0% and 26.1% depending on site • Hantavirus infections geographically widespread in city • They have been enzootic for at least 20 years (Cueto GR, Cavio R, Bellomo C, Padula PJ, Suarez OV, 2008, Trop Med & Int Hlth, 13, 1, 46-51.)
Rodents and public health • Strategies to address the risks to public health should be more than “individual treatments” • There is a need for a properly trained and equipped workforce within public authorities to devise and implement coherent pest management strategies • States should also establish more effective surveillance mechanisms
EU & the Biocidal Products Directive (BPD) etc • Process of assessment under BPD • Anti-coagulant rodenticides part of “Product Type 14” comprise 9 of 13 (70%) active substances approved under BPD and represent 90% of products used in practice • Cost and time to secure Annex 1 listing means 80% of active substances in EU in 2002 withdrawn by manufacturers • Moves on further restrictions and use of tamper resistant baitboxes required
Resistance & second generation anti-coagulants • Research to assess the extent of resistance underway in England and Wales • Without changes in approach it will be impossible to control rats with anti-coagulants in some parts of the UK • Restrictions on product approvals hamper control – e.g. Brodifacoum approved for indoor use only • Resistance also has an impact on non-target species and wildlife
Other pests - bedbugs • Bedbug (Cimex lectularius) numbers are increasing sharply • Nuisance and economic problem (especially in hotels) • Feeding at night on sleeping human hosts -itching caused by the bites; possibility of secondary infection are common • Ineffective treatments common • See NPAP Pest control procedures manual – Bedbugs (see http://www.cieh.org/npap)
Cuts and pest control services • NPAP Survey - for all pests, reduction in the overall number of LA.s providing in-house treatments only 89.9%. Provide any service. • Introductions of even token charges for pest control services decrease demand • In 2002 174 respondent LA.s provided free treatments for rats in domestic premises in 2009 it was 112 (- 36%) – figures for mice 121 in 2002 to 71 in 2009(- 41%)
Cuts and pest control services 2 • More LA.s taking enforcement action - less time spent in exploring other environmental health options? • Not necessarily the most cost effective approach • Loss of LA expertise in pest management & reduction in the services which protect some of the most vulnerable groups and those who are least likely to be able to afford to pay for services • Increase in ineffective DIY treatments?
Climate change • Yersinia pestis prevalence in gerbils in Central Asia increases with warmer springs and wetter summers • Possibility of increased tick-borne encephalitis (TBE) in Europe • Mosquito problems spatially and temporally more extensive in warmer climates • Biting insects – non-malarial mosquitoes; increased risk of West Nile Virus? Culex pipiens molestus causes serious biting nuisance.
Climate change • Risk from invasive species such as Aedes albopictus, hasbeen recorded in nine European countries and caused the Chikungunya outbreak in Italy • Malarial mosquito vectors - records of clusters of mosquito borne disease cases near airports - “airport malaria” , however land-use changes may be important factor and risk of malaria seems remote in the British Isles
Climate change and human behaviour • Alien invasive species are a large threat to biodiversity (Mack et al. 2000; IUCN 2008), and the economic damage they cause exceeds 5% of the global gross product (Pimentel 2002). • Synanthropic rats reflect human activity and are one of the most invasive species – will global travel etc increase infections within rodent population? • Human behaviour may also change with climate, bringing closer contact between rats and humans
Climate change and human behaviour.2 • Increased water-use and flooding with sewers running at full capacity – causing rats to abandon sewerage system • Lack of water compromises personal hygiene • Increased outdoor living • More food waste not correctly stored and disposed of (and spoilage) • Doors etc left open compromising “pest proofing” of buildings (dwellings)
Conclusion • A quick run through some issues • Pest management is often the forgotten part of environmental health • Pests can have both direct effects on health including mental health and the quality of life. • Governments need to take better account of pests and public health in policy development