Cost of health-related conditions

Public Health Significance of Urban Pests 163

5.6. Impact of poverty and lifestyle on risk of infestation

While today’s standard of living minimizes flea-vectored diseases in most European and North American communities, some population subsets experience chronic or sporadic disease outbreaks, requiring the involvement of public health personnel. Substandard housing, lack of appropriate veterinary care for domestic and feral dogs and cats, and other neighbourhood attributes predispose such communities as Native American reser- vations, inner-city apartments and homeless populations to flea exposure and the resul- tant transmission of disease. For such populations, pest control may not be economically feasible.

5.7. Flea management

As with most pests, the management of flea problems involves sanitation, source reduc- tion and exclusion. There are few biological control options for fleas, so pesticides play a major role in flea suppression Hinkle, Rust Reierson, 1997. Habitat manipulation focuses on creating an environment that is inhospitable to flea hosts, thus eliminating the vertebrate and its ectoparasitic load from proximity to people. The first priority is to identify the pest, because suppression strategies differ among flea species – for example, developing a control strategy for the cat flea is vastly different from dealing with discovery of a chigoe flea Tunga penetrans. Most cat flea control calls to pest control firms are from residences, not businesses, although an occasional infestation may occur in a warehouse or other structure where wildlife or feral animals reside. Flea management in and around man-made structures lends itself well to the concept of urban IPM Rust, 2005. Developing an integrated flea control programme necessitates understanding flea biology, population assessment techniques, mechanical control sys- tems, biological control, IGRs and traditional insecticide treatments Hinkle 2003. Once flea numbers have been reduced, environmental modification to exclude wildlife and feral animals from the area prevents flea reinfestation. Similarly, removing pet food at night avoids luring raccoons, opossums and other flea hosts onto properties where they share their fleas with pets, and covering openings to crawl spaces excludes animals from denning beneath the structure. New pesticidal products formulated to be used on the host have increased pet-owner compliance, due to enhanced efficacy, long-term activity and ease of application Rust, 2005. Therefore, cat flea control has shifted to reliance on these host-directed products, in conjunction with ancillary environmental treatments. Similarly, developing strategies to eliminate rodents from neighbourhoods will simulta- neously eliminate their flea populations, along with the pathogens they transmit. Again, the fleas should be identified, to ascertain the most likely hosts as well as their potential Fleas 162 flea-suppression efforts. For instance, the Vector-Borne Disease Section of the Division of Communicable Disease Control of the California Department of Health Services monitors campgrounds where plague is enzootic – that is, infecting animals in a parti- cular geographic area – and provides flea and rodent inspections and suppression Gerry et al., 2005. Annual surveillance costs for a typical California campground are estimated at US 7920 Kimsey et al., 1985; all estimates are adjusted for inflation. In years with epizootic episodes, control costs are estimated at US 63890, while the total cost – inclu- ding lost revenue, assuming the park must be closed for two months – is US 241540 Kimsey et al., 1985. Obviously this not only affects the economy of the park, but also affects the economy of the local area. These cost estimates do not take into account either the direct or indirect impacts of a human plague case and its public relations implications on regional tourism. As with most urban pests, construction practices that deny pests entry and establishment not only are more cost effective, but are also more dependable and long lasting. Also, retrofitting buildings and post-construction remediation are more expensive and are sel- dom completely satisfactory.

5.5.2. Cost of health-related conditions

While fleabites cause discomfort, they are not treated as medical conditions and people typically initiate palliative care using over-the-counter medications. When flea-allergic animals suffer unremitting dermatitis, however, veterinary intervention is necessary. This usually entails anti-pruritic medications and desensitization therapy, costs of which can be substantial. In some parts of the United States, over half the annual income of veterinary clinics is attri- butable to flea and tick product sales Scheidt, 1988, amounting to about US 1.7billion a decade ago Hinkle, 1997. The monthly cost of host-targeted products, such as pills or spot-ons topical ectoparasiticides applied in small volumes to the skin, averages US 10 per animal, considering only charges for the product. The worldwide market for ecto- parasite control products ectoparasiticides was estimated at about €1.1 billion, with the United States accounting for 67 of this market and western Europe 20 Krämer Mencke, 2001. Pet owners spend substantial sums about US1.12 billion in 1997 for FAD treatments about US 938 million, tapeworm prophylaxis and treatment about US 184 million and other flea-related problems Hinkle, 1997. The cost of a non-fatal human plague case was estimated to be about US 19761 adjus- ted for inflation; Kimsey et al., 1985, but increases in health care costs in the United States in the past two decades probably make this estimate low. As the vast majority of murine typhus cases are mild and go undiagnosed, there are no published estimates of their treatment costs. Individuals in whom disease is more severe often must be hospitalized for about a week, with attendant charges for such items as supportive care, laboratory tests, X-rays, antibiotic therapy and pharmaceuticals D.H. Walker, University of Texas Medical Branch, Galveston, TX, personal communication, 2006. Public Health Significance of Urban Pests 165 ted with fleas and only 10 of rural opossums carrying fleas Dryden et al., 1995. Rodent-proofing buildings and landscape modifications should be implemented to ensure the habitat is unsuitable for rodents and their fleas. Exclusion measures and sanitation practices prevent rats and other small mammals from dwelling near or entering buil- dings. By denying them food, water and harbourage, rodents and their ectoparasites can be eliminated from a neighbourhood.

5.7.3. Flea exclusion and physical removal