Food contamination and disease transmission

Public Health Significance of Urban Pests 63 Cockroaches 62 Data collected throughout the United States suggest that pesticide applications in schools may produce acute illness among school employees and students Alarcon et al., 2005. The authors indicate that these are “albeit mainly of low severity and with relatively low incidence rates”. Of the 2593 cases of illness examined, about 35 resulted from the insec- ticides. Of the 406 cases with more detailed information, 69 were associated with pes- ticides used in schools. The most common active ingredients reported were diazinon, chlorpyrifos, and malathion.

2.2.2. Allergy and asthma overview

In recent years, cockroach pest management has focused on the association between asthma and the presence of cockroach allergens see Chapter 1 of this report. Educational intervention and attempts to lower the source of cockroach allergens resulted in about a 60 reduction in cockroaches in the intervention group, compared with the non-inter- vention group McConnell et al., 2005. Although allergen loads in bedding were redu- ced by these efforts, kitchen levels remained high. Even low numbers of cockroaches can produce significant amounts of allergen. Over their lifetime, adult female German cockroaches can produce 25 000 to 50 000 units Gore Schal, 2005. In spite of reductions in cockroach numbers, the amount of aller- gen or cockroach dust often remains for longer than 6 months, even with aggressive clea- ning Eggleston, 2003. In summary, best pest management strategies seem to signifi- cantly reduce allergen, but not to below the disease threshold 8 Ug of house dust Katial, 2003. Clearly, additional research and new approaches are needed. Numerous studies have shown the association between and potential significance of cockroaches in lower-income households and asthma among children Brenner, 1995; Baumholtz et al., 1997. Rosenstreich and colleagues 1997 write that “exposure to coc- kroach allergen has an important role in causing morbidity due to asthma among inner city children”.

2.2.3. Food contamination and disease transmission

Cockroaches present a potential health problem to people and their companion animals. Brenner 1995 and Baumholtz and colleagues 1997 have provided extensive reviews of literature on the pathogens associated with cockroaches, including such pathogens as viruses, bacteria, fungi and molds. Table 2.2 is a summary and update of the important pathogenic bacteria, viruses and fungi reported for cockroaches. Fathpour, Emtiazi Ghasemi 2003 collected German, American and brownbanded cockroaches from hospi- tals, houses and poultry sheds in Iran. Of the 80 cockroaches tested, about 70 were contaminated with Salmonella spp., many of which were resistant to antibacterial drugs. Indirectly, cockroaches may affect human health by transmitting disease to agricultural products that ultimately end up in the human food supply. In the past 20 years, the pre- sence of German cockroaches has increased dramatically in Czech and Slovak dairies Stejskal Verner, 1996. Oriental cockroaches have been a problem in pig farms for Bacteria Alcaligenes faecalis Bacillus subtilis Campylobacter enteritis Campylobacter jejuni Clostridium novyi Clostridium perfringens Enterobacter aerogenes Escherichia coli B. orientalis, Auer, Asperger Bauer, 1994; B. germanica, Tarry Lucas, 1977 Klebsiella pneumoniae Listeria monocytogenes B. orientalis, Hechmer van Driesche, 1996 Mycobacterium leprae Nocardia spp. Proteus mirabilis Proteus morganii Proteus rettgeri Proteus vulgaris Pseudomonas aeruginosa Salmonella spp. B. germanica, P. americana, S. longipalpa , Rosenstreich et al., 1997 Salmonella bareilly Salmonella bovismorbificans Salmonella bredeney Salmonella enterica serotype Oranienburg Salmonella enterica serotype Panama Salmonella enteritidis B. orientalis, Auer, Asperger Bauer, 1994 Salmonella newport Salmonella paratyphi B Salmonella typhimurium B. germanica, P. americana, B. orientalis , Zurek Schal, 2004 Serratia marcescens Shigella dysenteriae Staphylococcus aureus B. orientalis, Auer, Asperger Bauer, 1994 Streptococcus faecalis Streptococcus pyogenes Vibrio spp. Yersinia pestis Table 2.2. List of pathogenic microbes isolated from cockroaches Fungi and moulds Alternaria spp. Aspergillus niger Aspergillus flavus Aspergillus fumigatus Candida krusei Candida parapsilosis Candida tropicalis Cephalosporium acremonium Cladosporium spp. Fusarium spp. Geotrichum candidum Mucor spp. Penicillium spp. Rhizopus spp. Trichoderma viride Trichosporon cutaneum Helminths Ancylostoma duodenale Ascaris lumbricoides Ascaris spp. Enterobius vermicularis Hymenolepis spp. Necator americanus Trichuris trichiura Protozoans Entamoeba histolytica Giardia spp. Viruses Poliomyelitis Source: Compiled from Brenner 1995; more recent citations shown in parentheses are included. Public Health Significance of Urban Pests 65 The costs of medical problems associated with cockroaches are difficult to estimate. Asthma affects 15 million Americans, approximately a third being under 8 years of age Benson Marano, 1998. Children allergic to cockroach allergen and exposed to high levels had a 3.4 times higher rate of hospitalization for asthma than other children. This group also had 78 more unscheduled visits to health care providers because of asthma. They also missed significantly more days of school than did other children Rust Reierson, 1991. An estimate of the national economic burden of asthma in the United States in 2000 is US 14.5 billion Krieger et al., 2002. The actual medical and societal costs associated with cockroach-related asthma might be a considerable portion of that cost.

2.3.2. Cost of control and management