Potential for parasite and bacteria transmission by paper currency in Nigeria.

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 the limited body of literature on microbial contamination of currency notes and to address growing community concerns about the risks associated with microbial contamination and handling of money worldwide.

Methods

Sampling Technique

A total of 500 samples of Nigerian currency (the Naira), comprising notes in all seven denominations ([naira]5, [naira]10, [naira]20, [naira]50, [naira]100, [naira]200, and [naira]500) were investigated. Coins were not sampled because they are no longer in circulation among the Nigerian general public. The investigation was conducted from September 2003 to December 2004. The currency samples were obtained during the two distinct seasons in the country (wet and dry seasons), in two batches (250 notes per batch) from four major cities (Lagos, Onitsha, Enugu, and Abakaliki). The notes came from various sources, including butchers, food sellers, bus conductors, farmers, beggars, roadside mechanics, and banks. The researchers randomly obtained the samples by purchasing an item or paying for a service using a large-denomination note, thus creating the need for change to be given. The change was placed in a sterile polyethylene bag, the bag was sealed, and the sample was taken to the Research Laboratory of the Department of Medical Microbiology/Parasitology at Ebonyi State University Abakaliki for analysis.

Physical Condition of the Currency

The currency notes were in various physical conditions and were categorized as mint, clean, or dirty/mutilated. The term mint describes currency notes that had been newly or recently produced and obtained from banks. These notes were included in the investigation as controls. The term clean describes notes that had a clean appearance without any obvious damage. The term dirty/mutilated describes notes that either were not clearly more than one-half of the original note or were in such condition that the value was questionable, or were damaged, soiled, or held together with bits of sticky tape.

Laboratory Investigation

Bacteriological and parasitological analyses were conducted. The first batch of 250 notes was analyzed for parasites, and the second batch of 250 notes was analyzed for bacteria.

Bacteriological Analysis

Isolation of various bacterial contaminants from the currency notes was performed via standard techniques described previously (Gilchrist, 1993; Singh et al., 2002). Briefly, a sterile, cotton-tipped swab moistened with sterile physiological saline was used to swab both sides of the currency note. The swabs were directly inoculated on blood agar and MacConkey agar. The pairs of inoculated media were incubated aerobically at 35-37[degrees]C for 24 hours and then examined for bacterial growth according to standard protocol described previously (Cheesbrough, 2000). The authors isolated bacteria by assessing colony characteristics and Gram reaction, and by conducting catalase and coagulase tests; hemolysis, sugar fermentation, and other biochemical tests, including tests for indole production, citrate utilization, and urase activity; triple sugar iron (TSI) agar tests (for glucose, sucrose, and lactose fermentation); gas and hydrogen sulfide production tests; and oxidase tests, according to protocols described previously (Cheesbrough). Bacteria were identified but were not quantified.

Parasitological Analysis

Standard concentration techniques for the isolation of enteric parasites were used as described previously (Cheesbrough 1998; WHO, 2003). The swab was made of very light foam material, which was cut into pieces 2 cm x 2 cm, washed with detergent, and sterilized in a dilute solution of sodium hypochlorite. The pieces of foam were then rinsed in water, air-dried, and rinsed in 70 percent alcohol. They were oven-dried and stored in a well-covered container until used. Each piece of foam was moistened with formol-saline solution and used to swab both sides of the currency note. The swab was placed in a capped bottle containing 10 mL of formol-saline solution, and the bottle was shaken vigorously. Thereafter, the swab was pressed against the inner sides of the bottle with a sterile forceps and removed. The solution was poured into a centrifuge tube and centrifuged at 2,000 g for 5 minutes. The supernatant was decanted, and a drop of the sediment was placed on a glass slide, covered with a glass cover slip and examined microscopically for parasite ova. Identification of parasites was made according to standard guidelines (WHO, 2004). Parasites were identified, but were not quantified.

Statistical Analysis

Differences between proportions were assessed by Chi-square analysis. Statistical significance was set at .05.

Results

Of the 250 currency notes on which parasitological analysis was conducted, 54 (21.6 percent [95 percent CI: 16.50-26.70]) were contaminated with enteric-parasite ova. A total of 13 (22.8 percent) of the 57 clean notes and 41 (30.6 percent) of the 134 dirty/mutilated notes were contaminated with parasites. Bacteriological analysis indicated that 133 (53.2 percent, [95 percent CI: 47.02-57.39]) of the second batch of 250 notes were contaminated with bacteria: 37 (52.9 percent) of the 70 clean notes and 96 (73.8 percent) of the 130 dirty/mutilated notes. Neither parasite ova nor bacteria were found on the mint notes (Table 1). Parasites isolated from the currency notes included Ascaris lumbricoides (8.0 percent), Enterobius vermicularis (6.8 percent), Trichuris trichiura (2.8 percent), and Taenia species (4.0 percent). Bacteria isolated from the notes were Streptococcus species (21.6 percent), Staphylococcus species (12.8 percent), Escherichia coli (13.2 percent), and Bacillus species (5.6 percent).

Contamination was related to denomination of currency. Contamination with parasites was most prevalent among [naira]100 notes (30.0 percent) and [naira]5 notes (27.3 percent) and less prevalent among [naira]50 notes (9.0 percent). None of the [naira]500 notes had any parasite contamination. The association between parasite contamination and denomination of currency was not statistically significant, however ([chi square] = 5.13, df = 6, p > .05) (Table 2). Contamination with bacteria was most prevalent among the [naira]5 notes (62.2 percent) and least prevalent among the [naira]500 notes (32.0 percent). The association between bacterial contamination and denomination of currency also was not statistically significant ([chi square] = 10.30, df = 6, p > .05) (Table 2).

Contamination was also related to the physical condition of the currency; parasite contamination was most prevalent among dirty/mutilated notes, at 30.6 percent, while 22.8 percent of the clean notes had parasite contamination. There was a statistically significant association between parasite contamination and physical condition of the currency ([chi square] = 25.932, df = 2, p < .05) (Table 2). The dirty/mutilated notes also had the highest prevalence of bacterial contamination (73.8 percent). Among the clean notes, 52.9 percent were contaminated with bacteria. Chi-square analysis indicated a statistically significant association between bacterial contamination and currency condition ([chi square] = 79.030, df = 2, p < .05) (Table 2).

Parasite contamination was most prevalent among currency notes obtained from butchers (40.0 percent [95 percent CI: 24.82-55.18]), next most prevalent among notes obtained from farmers (35.7 percent [95 percent CI: 17.95-53.45]) and beggars (34.4 percent [95 percent CI: 17.94-50.81]), and least prevalent among notes obtained from roadside mechanics (12.1 percent). The association between parasite contamination and currency source was statistically significant ([chi square] = 33.285, df = 6, p < .05) (Table 3). Bacteriological analysis found a high prevalence of contamination, with the highest prevalence observed among currency notes obtained from beggars (84.8 percent [95 percent CI: 72.55-97.05]), butchers (78.0 percent [95 percent CI: 65.32-90.68]), and food sellers (62.1 percent [95 percent CI: 44.44-79.76]). Notes from farmers had the lowest prevalence of bacterial contamination (50.0 percent). Neither parasite nor bacterial contamination was observed on notes from banks. Statistical analysis also showed a significant association between prevalence of bacterial contamination and currency source ([chi square] = 82.499, df = 6, p < .05) (Table 3).

Discussion

The isolation of bacterial and parasitic agents from currency notes in the study reported here confirmed that currency might be a vector playing an important role in the transmission of pathogenic microorganisms, as well as in the spread of drug-resistant strains in the community. Bacterial agents that can contaminate currency notes--for example, some strains of Streptococcus and Staphylococcus--are known to have developed resistance to conventional antibiotics (WHO, 2000). This situation is more pronounced in developing countries, including Nigeria, where inadequate health services, inadequate drug supplies, non-adherence to treatment strategies, and dubious drug quality all favor the emergence of microbial resistance.

Many wealthy developed countries have exclusively focused efforts on fighting diseases within their own borders, while failing to help eliminate the diseases globally. After proliferating elsewhere, many bacteria, viruses, and parasites mutate, become drug resistant, and venture back to wealthy countries via modern transportation and especially via money, which now travels along social and economic networks globally (Spivack, 2005; WHO, 2000).

The study revealed a higher prevalence of bacteria than of parasite contamination (53.2 percent versus 21.6 percent), a finding that was not unexpected. Pope and co-authors (2002) have demonstrated in their study in western Ohio that bacteria are capable of growing on currency notes. Enteric parasites do not possess this capability. In addition, the relative abundance of the resident or normal skin flora, as well as transient bacteria that may be found on the skin, could enhance an easy transfer to inanimate objects like currency notes (Goktas & Oktay, 1992; Noble, 1993; Pope et al.). Consequently, the handling of paper currency deserves special attention. The results of the study reported here confirm how important it is for food handlers, whether at a restaurant or at home, to always wash their hands thoroughly after handling currency and before handling food.

A significant association was found between parasite/bacteria contamination and the condition of the currency (p < .05), with higher rates of both bacteria and parasite contamination on the dirty/mutilated notes. This finding has very important health and economic implications, especially in underdeveloped and developing tropical nations of the world and particularly in Asia and Africa (Siddique, 2003). The climatic and environmental conditions of the tropics favor the thriving of many pathogenic microorganisms, and in the face of underdevelopment, inadequate water and sanitation, crowded living conditions, lack of access to health care, and low levels of education, a greater proportion of the populace, particularly the poor, become highly susceptible to infection and disease (Anderson & May, 1991; Gwatkin & Guillot, 2000). Thus the risk of infection is increased severalfold when objects that change hands at a high frequency, such as currency notes, are contaminated with microbes. The risk is by no means restricted to residents of the country in question; it might even be greater for expatriates, tourists, and visitors from other countries, who may not be immune to the pathogens (Siddique).

In the study reported here, a random approach was adopted for currency sampling; whatever money was provided was collected. The implication is that the majority of the people are exposed to dirty notes. In Nigeria, poor-currency-handling culture is widespread, and there is indiscriminate abuse of currency notes. A great majority of the populace does not carry money in wallets, and squeezing of currency notes is a common occurrence. Women, especially among the unenlightened, often place money underneath their brassieres, while men place theirs in their socks. These activities not only enhance currency contamination but may also increase the risk of infection from contaminated notes. The situation is further compounded by the inability of the Nigerian government to consistently withdraw old, worn-out, and mutilated notes from circulation. The presence of damaged currency notes and the failure to consistently withdraw them from circulation are common phenomena in many parts of Africa and Asia (Gadsby, 1998; Podhajny, 2004). The persistence of damaged or terribly mutilated notes in active circulation (some so damaged that they can no longer be stuck together) could elevate their contributory role in transmission of some pathogens, thereby constituting potential public health hazard.

Interestingly, the ova of A. lumbricoides, E. vermicularis, T. trichiura, and Taenia species were isolated from the currency notes. Their presence on objects that frequently change hands is known to be a reflection of poor local environmental sanitation and personal hygiene (Hotez, Silva, Brooker, & Bethony, 2003). These conditions are typical of most tropical and subtropical regions of the world, where up to 15 percent of the host population harbor approximately 70 percent of the worm population and serve as major source of environmental contamination (Bundy, 1995). Handling money is like shaking hands with somebody, so improvement of personal hygiene and the cultivation of regular, scrupulous handwashing cannot be overemphasized.

Of all the intestinal helminths isolated, A. lumbricoides occurred with the highest frequency. One possible reason for this is the resilience of the ova. It is well established that the infective stages of A. lumbricoides, the embryonated eggs, have enormous capacity for withstanding the environmental extremes of urban environments (Hotez et al., 2003). Furthermore, A. lumbricoides eggs are coated with a mucopolysaccharide that renders them adhesive to a wide variety of environmental surfaces; this feature accounts for their adhesiveness to everything from door handles to dust, fruits and vegetables, paper money, and coins (Crompton, 1989; Kagei, 1983).

Streptococcus species, Staphylococcus species, E. coli, and Bacillus species were isolated from the notes studied. This result is similar to those of studies by Khin and co-authors (1989) in Rangoon, Myanmar; Goktas and Oktay (1992) in Turkey; and Pope and co-authors (2002) in Ohio, all of which strongly suggested that money plays a role in the transmission of antibiotic-resistant and potentially harmful bacterial agents. The bacteria isolated in those studies, such as coagulase-negative Staphylococcus, alpha-hemolytic Streptococcus, Enterobacter species, Acinetobacter species, non-aeruginosa species of Pseudomonas, Bacillus species, Alcaligenes species, diphtheroids, and Escherichia vulneris, do not typically cause infections in healthy people. These bacteria have, however, been known to cause significant infections in those with depressed immune systems, including those infected with HIV, those undergoing cancer chemotherapy, or those taking other medications that depress the immune system. Those bacteria may also cause infection in hospitalized patients (Emori & Gaynes, 1993; American Society for Microbiology, 2001).

The study reported here found no significant association (p > .05) between contamination with parasites or bacteria and denomination of currency, although contamination was relatively more prevalent among lower-denomination notes, presumably as a result of a higher rate of handling and hand-to-hand exchange (Gadsby, 1998). The results did not suggest that any one denomination was particularly susceptible to or protected against contamination, since pathogens were found on all denominations of the currency notes and were absent only on the mint notes from banks. Siddique (2003) reports that in Bangladesh, a foreign bank wins business by guaranteeing its customers a steady supply of fresh, new currency notes. This practice may not guarantee absence of microbial contamination, but it could minimize the risk of currency-associated infection.

A significant association (p < .05) was established between contamination and sources of currency, with the highest levels of contamination found among currency notes from beggars and butchers. Khin and co-authors (1989) isolated high levels of enteric pathogens from paper-money samples obtained from butchers and fish mongers in a local market in Rangoon, Myanmar. In most developing countries, including Nigeria, sanitation facilities at slaughterhouses and meat markets are grossly inadequate, resulting in very poor environmental sanitation, thus enhancing cross-contamination from simultaneous handling of money and animal products. Major cities in Nigeria, as in other developing tropical countries, are witnessing an influx of street beggars. Most of these individuals live under severely unhygienic conditions, appear sick, and sometimes have putrefying sores on their bodies. It was not surprising that currency notes obtained from them were highly contaminated.

A major drawback of the study was the authors' inability to quantify the cell numbers of the bacterial agents and the density of the parasites on the currency notes. This undertaking is advocated for future studies. Another limitation of the study was its failure to take into account the possible presence of other categories of potential pathogens, such as viruses and fungi, that might contaminate currency notes. Future studies addressing pathogens of these types are advocated. It is worth noting that in this investigation, the authors were not able to adequately prove that the identified pathogens could be transmitted from person to person during the exchange of paper currency. The authors recommend that a more complex study be undertaken, using molecular-biology tools, to achieve this goal.

In conclusion, the results of the study reported here support previous work on contamination of currency by pathogenic microorganisms (Goktas & Oktay, 1992; Khin et al., 1989; Pope et al., 2002) and suggest that paper currency might be contaminated not only with bacteria but also with enteric parasites, especially in the tropics. The practice of licking or applying saliva to the fingers while counting paper money is worth mentioning as an important potential route of exposure to bacteria and enteric parasites.

Strategies to reduce the contamination of currency, especially where environmental conditions favor the abundance of many pathogens, are recommended. Such strategies could include the introduction of plastic currency, which can be washed easily, as was done in Australia (the first country to do so) in 1988 (Brady & Kelly, 2000; Science Notes, 2000). Other recommendations are the regular disinfection of currency deposited in banks and post offices by ultraviolet light or formalin vapors (Singh et al., 2002), regular withdrawal of damaged notes by federal authorities, and, most important, the improvement of personal hygiene. Spivack (2005) has noted the possibility of terrorists contaminating banknotes with pathogens and then putting those notes back into circulation. Regular microbial testing of currency notes and establishment of a method for large-scale replacement of contaminated notes are recommended by Spivack along with other public health measures. Finally, the authors recommend that similar studies on the microbial contamination of currency be undertaken in other countries to enrich the global information bank on the subject; the issue is becoming a major public health concern worldwide.

Corresponding Author: C.J. Uneke, Lecturer II/Coordinator of Research in Parasitology, Ebonyi State University, Department of Medical Microbiology/Parasitology, Faculty of Clinical Medicine, College of Health Sciences, KM 7 Abakaliki-Enugu Express Way, Abakaliki, PMB 053 Nigeria. E-mail: [e-mail].

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Although most of the information presented in the Journal refers to situations within the United States, environmental health and protection know no boundaries. The Journal periodically runs International Perspectives to ensure that issues relevant to our international constituency, representing over 60 countries worldwide, are addressed. Our goal is to raise diverse issues of interest to all our readers, irrespective of origin.

C.J. Uneke, M.Sc.

O. Ogbu, M.Sc., Ph.D.

TABLE 1 Parasite and Bacteria Contamination of Notes in Relation to
Physical Condition of Currency Notes

                                       Currency Condition
                            Mint          Clean         Dirty/Mutilated
                            Number (%)    Number (%)    Number (%)
Pathogens                   Contaminated  Contaminated  Contaminated

Parasites                   (N = 59)      (N = 57)      (N = 134)
  Ascaris lumbricoides      0 (0.0)        6 (10.5)     14 (10.4)
  Enterobius verniculiaris  0 (0.0)        3 (5.3)      14 (10.4)
  Trichuris trichura        0 (0.0)        3 (5.3)       7 (5.2)
  Taenia species            0 (0.0)        1 (1.8)       6 (4.5)
  Total                     0 (0.0)       13(22.8)      41 (30.6)
Bacteria                    (N = 50)      (N = 70)      (N = 130)
  Streptococcus species     0 (0.0)       17 (24.3)     37 (28.5)
  Staphylococcus species    0 (0.0)        9 (12.9)     23 (17.7)
  E. coli                   0 (0.0)        7 (10.0)     26 (20.0)
  Bacillus species          0 (0.0)        4 (5.7)      10 (7.7)
  Total                     0 (0.0)       37 (52.9)     96 (73.8)

                                   Currency Condition
                            Total
                            Number (%)    95% Confidence
Pathogens                   Contaminated  Interval

Parasites                   (N = 250)
  Ascaris lumbricoides       20 (8.0)      4.64-11.36
  Enterobius verniculiaris   17 (6.8)      3.68-9.92
  Trichuris trichura         10 (4.0)      1.51-6.43
  Taenia species              7 (2.8)      2.16-3.44
  Total                      54 (21.6)    16.50-26.70
Bacteria                    (N = 250)
  Streptococcus species      54 (21.6)    16.50-26.70
  Staphylococcus species     32 (12.8)     8.66-16.94
  E. coli                    33 (13.2)     9.00-17.40
  Bacillus species           14 (5.6)      2.75-8.45
  Total                     133 (53.2)    47.02-59.39

TABLE 2 Parasite and Bacteria Contamination of Notes in Relation to
Currency Denomination

                              Denomination
                  N500            N200             N100
             EX (a)  CON (b)  EX (a)  CON (b)  EX (a)  CON (b)

Parasites, by condition of notes
Mint          5        0       7        0       7        0
                      (0.0)            (0.0)            (0.0)
Clean         3        0       6        2       8        3
                      (0.0)           (40.0)           (37.5)
Dirty/        2        0       7        2      15        6
  mutilated           (0.0)           (28.6)           (40.0)
Total        10        0      20        4      30        9
                      (0.0)           (20.0)           (30.0)

Bacteria, by condition of notes
Mint          5        0       5        0       5        0
                      (0.0)            (0.0)            (0.0)
Clean        10        2      10        4      10        5
                     (20.0)           (40.0)           (50.0)
Dirty/       10        6      10        6      10        6
  mutilated          (60.0)           (60.0)           (60.0)
Total        25        8      25       10      25       11
                     (32.0)           (40.0)           (44.0)

                              Denomination
             N50              N20              N10
             EX (a)  CON (b)  EX (a)  CON (b)  EX (a)  CON (b)

Parasites, by condition of notes
Mint         10        0      10        0      10        0
                      (0.0)            (0.0)            (0.0)
Clean        10        4      10        4      10        1
                     (40.0)           (40.0)           (10.0)
Dirty/       20        8      25        5      30        7
  mutilated          (40.0)           (20.0)           (23.3)
Total        40       12      45        6      50        8
                      (9.0)           (13.3)           (16.0)

Bacteria, by condition of notes
Mint          5        0      10        0      10        0
                      (0.0)            (0.0)            (0.0)
Clean        10        6      10        6      10        7
                     (60.0)           (60.0)           (70.0)
Dirty/       25       18      25       19      25       20
  mutilated          (72.0)           (76.0)           (80.0)
Total        40       24      45       25      45       27
                     (60.0)           (55.6)           (60.0)

                   Denomination
             N5               Total
             EX (a)  CON (b)  EX (a)  CON (b)

Parasites, by condition of notes
Mint         10        0       59       0
                      (0.0)            (0.0)
Clean        10        2       57      13
                     (20.0)           (22.8)
Dirty/       35       13      134      41
  mutilated          (37.1)           (30.6)
Total        55       15      250      54
                     (27.3)           (21.6)

Bacteria, by condition of notes
Mint         10        0       50       0
                      (0.0)            (0.0)
Clean        10        7       70      37
                     (70.0)           (52.9)
Dirty/       25       21      130      96
  mutilated          (84.0)           (73.8)
Total        45       28      250     133
                     (62.2)           (53.2)

(a) EX = number examined.
(b) CON = number contaminated (percentage given in parentheses).

TABLE 3 Parasite and Bacteria Contamination of Notes in Relation to
Currency Sources

Currency                      Parasite Contamination
Source              EX (a)  CON (b)    95% Confidence Interval

Butchers             40     16 (40.0)  24.82-55.18
Farmers              28     10 (35.7)  17.95-53.45
Beggars              32     11 (34.4)  17.95-50.86
Food sellers         27      7 (26.0)   9.46-42.555
Bus conductors       31      6 (19.1)   5.26-32.93
Roadside mechanics   33      4 (12.1)   0.97-23.23
Banks                59      0 (0.0)   --
Total               250     54 (26.1)  16.50-26.70

Currency                      Bacteria Contamination
Source              EX (a)  CON (b)      95% Confidence Interval

Butchers             41      32 (78.0)   65.32-90.68
Farmers              30      15 (50.0)   32.11-67.89
Beggars              33      28 (84.8)   72.55-97.05
Food sellers         29      18 (62.1)   44.44-79.76
Bus conductors       33      19 (57.6)   40.74-74.46
Roadside mechanics   34      21 (61.8)   45.47-78.13
Banks                50       0 (0.0)    --
Total               250     133 (53.20)  47.02-59.39

(a) EX = number examined.
(b) CON = number contaminated (percentage given in parentheses).