Potential for parasite and bacteria transmission by paper currency in Nigeria.(INTERNATIONAL PERSPECTIVES)

Introduction

A classic characteristic of human parasitic and bacterial agents is the evolution of routes for transmission to susceptible hosts. The environment plays a critical role in transmission to humans, with many environmental materials serving as vehicles (Anderson & May, 1991; Struthers & Westran, 2003). Microbial contaminants may be transmitted either directly, through hand-to-hand contact, or indirectly, via food or other inanimate objects. These routes of transmission are of great importance in the health of many populations in developing countries, where the frequency of infection is a general indication of local hygiene and environmental sanitation levels (Cooper, 1991).

The possibility that currency notes might act as environmental vehicles for the transmission of potential pathogenic microorganisms was suggested in the 1970s (Abrams & Waterman, 1972). Paper currency is widely exchanged for goods and services in countries worldwide. It is used for every type of commerce, from buying milk at a local store to trafficking in sex and drugs. All this trade is hard on currency, with lower-denomination notes receiving the most handling because they are exchanged many times (Gadsby, 1998). Although paper currency is made to take abuse (up to 4,000 folds in each direction) in most parts of the world, including in Nigeria (where paper currency is a rugged mix of 75 percent cotton and 25 percent linen), it lasts less than a few years in circulation (Gadsby, 1998). The average U.S. dollar, for instance--like most currency notes worldwide--lasts a mere 18 months (Gadsby). Paper currency also provides a large surface area as a breeding ground for pathogens (Podhajny, 2004).

Money on which pathogenic microorganisms might survive represents an often overlooked reservoir for enteric disease (Michaels, 2002). In most parts of the developed world, there is a popular belief that the simultaneous handling of food and money contributes to the incidence of food-related public health incidents (Food Science Australia [FSA], 2000). Over the last two decades, data indicating that simultaneous handling could indeed be a cause of sporadic foodborne-illness cases have accumulated from studies of the microbial status and survival of pathogens on coins and currency notes in Turkey (Goktas & Oktay, 1992); the United States (Dow Jones News, 1998; Jiang & Doyle, 1999; Pope, Ender, Woelk, Koroscil, & Koroscil, 2002); Australia (FSA, 2000); India (Singh, Thakur, Kalpana, & Goel, 2002); Egypt (El-Dars & Hasssan, 2005); China (Xu, Moore, & Millar, 2005); and Rangoon, Myanmar (Khin, Phyu, Aung, & Aye, 1989).

An investigation that was reported in 1997 and that involved swabbing and culturing from various coins and paper money collected at random from doctors, laboratory staff, and other employees at a New York hospital resulted in the recovery of many pathogenic microorganisms (Dow Jones News, 1998; FSA, 2000). The possibility of currency contamination with microorganisms has also been observed among food handlers. An assessment of the public health risk associated with the simultaneous handling of food and money in the food industry in Australia (Brady & Kelly, 2000) analyzed money handled by people who were also food handlers for the presence and levels of microorganisms. In the study, the presence of coagulase-positive staphylococci on the money surface was confirmed. This suggested that without hygienic intervention, human occupational activities, especially those involving simultaneous money handling, could introduce the risk of cross-contamination to foods (FSA, 2000). With a number of infectious intestinal diseases, a low dose of the infectious agent is capable of causing illness; therefore, failure of food service workers to adequately sanitize hands or use food-handling tools (tongs, spoons, utensils or bakery/serving papers) between the handling of money and the serving of food could put food service patrons at risk (Michaels, 2002).

Oddly, publications regarding the degree to which paper money is contaminated with bacteria are few and far between, as the authors found when they conducted a Medline search in December 2005 (Abrams & Waterman, 1972; El-Dars & Hassan, 2005; Goktas & Oktay, 1992; Jiang & Doyle, 1999; Khin et al., 1989; Michaels, 2002; Pope et al., 2002; Singh et al., 2002; Xu et al., 2005). Furthermore, the search found no documented study of the parasitological status of currency notes (as of December 2005). Scientific information on the contamination of money by microbial agents is also lacking in most developing countries in sub-Saharan Africa, including Nigeria. This dearth of information may have contributed to the absence of public health policies or legislation on currency usage, handling, and circulation in many parts of Africa. Although the studies done in the United States and Australia have had no major impact on policies or legislation on currency handling and circulation in those countries, they have fostered a higher level of public awareness about the potential for currency contamination by microorganisms (Dow Jones News, 1998; FSA, 2000; Michaels; Jiang & Doyle; Pope et al.). In the United States, a whole division of the Department of Treasury deals with what is termed "mutilated currency," and the department Web site boasts many examples of beleaguered, burned, buried, water-damaged money (Siddique, 2003).

An aspect of food service that frequently causes comment, particularly among enlightened consumers, is the way a food handler prepares the food, takes money for the purchase, returns change to the customer, and then prepares food for the next customer. This pattern is most noticeable in sandwich bar operations, but is by no means restricted to outlets of that type. Anything that gets on hands can get on money. The study reported here, therefore, was designed to add to …