CHAPTER ONE
1.0
INTRODUCTION
Various factors have been identified which play important role in the transmission of
disease agents from one individual to another. These include food, water, air current, direct
contact, contact through items of clothing etc. Furthermore, disease transferred through these
agents may be restricted to very limited locales but may be in some cases result in epidemic
outbreaks (Cooper, 1991).
The possibility that currency notes might act as environmental vehicles for the
transmission of potential pathogenic microorganisms was suggested in 1970s (Abrams &
Waterman, 1972). Globally, money is one of the items most frequently passed from hand to
hand. During its passing, money can get contaminated and may thus play a role in the
transmission of microorganisms to other people (Osim et al., 1996).
Various denomination of the naira notes have been minted by the Central bank of Nigeria
(CBN). They are released to the public, through the Commercial banks. Currently, there are eight
denominations of the naira in note form: N5, N10, N20, N50, N100, N200, N500 and N1000
notes. The N5, N10, N20, N50, N100 and N200 naira notes are the most common and are more
involved daily cash transactions. They are common especially among the populace while the
N500 and N1000 notes are commonly used among the wealthy and in corporate transactions
(Okon et al., 2003). Individuals handling the notes shed some of their body flora on the notes;
leading to the spread of the microorganisms among the handlers. This has been implicated in
serious health hazard such as impairment of lungs function (Osim, 1996). The contamination of
the notes can be traced to dust, soil, water, micro flora of the body of handlers (hand, skin, etc.),
1
for example, money may get contaminated with microorganisms from the respiratory- and
gastro-intestinal tract during counting, the saliva often used when counting the notes(Umeh et
al., 2007).
Money is not usually suitable for the survival of microorganisms, except for some that
are resistant to external conditions and non-resistant forms of spores. In addition, the general
hygiene levels of a community or society may contribute to the amount of microbes found on
coins and notes, and thus the chance of transmission during handling of money. Some money
handling habits such as: keeping naira notes in brassiere, socks and pockets, under the carpet or
rugs and squeezing in the hand frequently introduce microbes to the notes. Citrobacter sp.,
Mycobacterium lapiae, Salmonella sp., Shigella sp., Escherichia coli, Staphylococcus aureus and
Pseudomonas aeroginosa have been isolated from naira notes (Haque, 2003). Most of them are
normal flora of the human skin; however, some e.g. S. aureus and P. aeroginosa can be
opportunistic pathogens. This suggests that the notes could serve as formites for some infectious
agents (Osim, 1996).
In this study dirty naira notes of different denominations were collected and analyzed for
their bacteriological quality as indicated by the kinds of bacteria they harbor.
1.2 AIM AND OBJECTIVES
1.2.1 AIM
The aim of this study is to determine money as a possible vehicle of bacterial infection.
1.2.2 OBJECTIVES
 To determine bacterial types and population on Naira notes.
 To isolate and identify bacterial pathogens on Naira notes.
2
CHAPTER TWO
2.0 LITERATURE REVIEW
Entering the antibiotic era, it was anticipated that morbidity and mortality from infectious
diseases would continue to decrease over time. However, the death rate from infectious diseases
increased by 58% from 1980 to 1992, making it the third leading cause of death in the world by
1992 Furthermore, with the emergence of drug-resistant pathogens, many infections have
become more difficult to treat. (Pinner et al., 1996).
2.1 ROUTES OF TRANSMISSION OF INFECTION
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).
2.2 LIFESPAN OF NAIRA NOTES
According to Central Bank of Nigeria (CBN), the expected lifespan of the Naira notes is
24 months but the mishandling reduces this to less than 6 months. The abused Naira note denotes
the currency, which had been fairly long (not more than 24 months) in circulation, mishandled,
structurally disfigured, literally mutilated and for most of the time they are dirty (Okon et al.,
2003).
3
2.3 POSSIBLE ROLE OF MONEY IN DISEASE TRANSMISSION
The possibility that money might act as environmental vehicles for the transmission of
potential pathogenic microorganisms was suggested in 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 in hard currency, with lower-denomination notes receiving the most handling
because they are exchanged many times (Gadsby, 1998). Paper currency 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 (Michael, 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 (FSA, 2000). Over the last two decades, the
observed data indicated that simultaneous handling indeed was a cause of sporadic food borneillness and survival of pathogens on currency notes in Turkey (Goktas & Oktay, 1992), United
States (News, 1998; Jiang & Doyle, 1999; Pope et al., 2002), Australia (FSA, 2000), India
(Singh et al., 2002), Egypt (El-Dars & Hassan, 2005), China (Xu etal., 2005), and Myanmar
(Khin New et al., 1989). An aspect of food service that frequently causes comment, 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. Anything that gets on hands can get on money. To
date no outbreak of food borne and other illness have been associated with infection from
money. However evidences for the presence of pathogenic bacteria on currency reinforces the
need for strict adherence to hygienic practices among money handlers who also handle food and
water (Prasai et al., 2008).
4
2.4 AGENTS OF INFECTIOUS DISEASE
Bacterial genera such as Citrobacter sp., Mycobacterium lapiae, Salmonella sp., Shigella
sp., Escherichia coli, Staphylococcus aureus and Pseudomonas aeroginosa have been reported to
be continually shed by convalescing patients during the carrier stage (Haque, 2003). An
assessment of the public health risk associated with the simultaneous handling of food and
money in the food industry in Australia (Brady, 2000) showed the presence of Staphylococci on
the money surface. 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. 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).
Incidentally, abused Naira notes were reported as vehicles of bacterial, mold and other
parasitic infections and agents of cross contamination (Jolaoso, 1991; Awodi et al., 2001; Itoda,
2001). Studies from other parts of world (Shukla, 1980; Oyler et al., 1996; Pachter et al., 1997;
Havas, 2000) have also shown that bank notes revealed the presence of high load of germs,
which could cause tuberculosis, meningitis, pneumonia, tonsillitis, peptic ulcers, genital tract
infections, gastro-intestinal tract infections and lung diseases. Contact with contaminated
currency notes could also cause diarrhoea and urinary tract infections besides skin burn and
septicaemic infections (Siddique, 2003).
Publications regarding the degree to which paper money is contaminated with bacteria
are few (Abrams, 1972; Khin Nwe, et al. 1989; Goktas & Oktay, 1992; Jiang & Doyle, 1999;
5
Michaels, 2002; Pope, 2002; Singh et al., 2002; El-Dars & Hassan, 2005; Xu et al., 2005).
Scientific information on the contamination of money by microbial agents is lacking in most
developing countries. This dearth of information may have contributed to the absence of public
health policies or legislation on currency usage, handling, and circulation in the countries like
United States and Australia have fostered a higher level of public awareness about the potential
for currency contamination by microorganisms (News 1998, Jiang & Doyle 1999, FSA 2000,
Michaels 2002, Pope et al. 2002). 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).
The abused Nigerian currency has become an issue of concern particularly in the recent
times when the CBN embarked on a nationwide enlightenment campaigns aimed at educating the
public on the proper ways of handling the Naira notes (Okon et al., 2003).
In view of the high possibility that bacterial pathogens could be transmitted through
contaminated currency notes, it is important to conduct a microbiological examination to
determining bacterial population and types on money.
6
CHAPTER THREE
3.0 MATERIALS AND METHODS
3.1 MATERIALS
The major material used in this experiment is abused naira note of different
denominations.
3.2 APPARATUS/INSTRUMENTATION
The apparatus used in this experiment were conical flask, 1000 cm3 measuring cylinder
(as a collector), test tubes, beakers, syringe, petri dishes, slant bottle, wire loop, hot plate,
autoclave and incubator respectively.
3.3 METHODS
3.3.1 COLLECTION OF SAMPLES:
A total of 24 samples of Nigerian currency (the Naira), comprising notes in all eight
denominations (Naira 5, 10, 20, 50, 100, 200, 500 and 1000) were investigated. Coins were not
sampled because they are no longer in circulation among the Nigerian general public. The
sample were randomly obtained by purchasing an item or paying for a service using a largedenomination note, thus creating the need for change to be given, in some instance Naira
samples were obtained in exchange for bigger denominations.
The currency sample were
randomly collected from bus conductors, motor-cycle rider, traders, business operators, food
sellers, beggars and other individuals in Maggi market (Sokoto metropolis) and Usmanu Dafodio
University main campus. On the other hand, 2 pieces of fresh Naira mints of each denomination
were also obtained from the Central Bank of Nigeria, Sokoto branch, which served as a control.
7
Samples were collected in sterile leather bags using disposable sterile hand gloves. These were
then labeled and taken to the laboratory for analysis (Baker and Silverton, 1985).
3.3.2 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 CBN, Sokoto branch. 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.
3.4 PREPARATION OF MONEY FOR ANALYSIS:
Each abused Naira note collected was soaked in 100 ml aliquots of sterile buffered (0.1% w/v)
peptone water (oxoid) for 20 minutes at ambient temperature with regular vigorous shaking to
dislodge the cells into suspension (Collins, 1989).
3.5 BACTERIOLOGICAL ANALYSIS
To determine total viable count, The washed water of the soaked notes was serially
diluted (10-1 to 10-4) and the dilution (0.5 ml) of each washing was inoculated (using pour-plate
method) on sterile plates of nutrient (oxoid) agar medium. The plates were incubated at 37ºC for
24 hours.
Representative colonies of bacterial isolates were selected and purified by sub
culturing on selective and enriched media. Pure culture were then characterized and subsequently
identified using Cowan and Steel’s Manual for the identification of Medical Bacteria (Barrow
and Feltham, 1995). Data obtained were subjected to statistical analysis using the Students’ T
8
test (Oyejola, 2004). Morphological characteristics, Gram staining and biochemical test were
used to confirm the bacteria isolated. (Cheesbrough, 2000).
3.6 MEDIA PREPARATION
The media was prepared by dissolving 28g to nutrient agar in one liter of distilled water.
The mixture was dissolved on the hot plate to achieve total dissolution of the nutrient agar. It was
then corked with cotton wool and aluminum foil, and was sterilized in the autoclave at 121oc for
15minutes. The media was allowed to cool to 45oc and was dispensed into different sterile Petri
dish and allowed to solidify (Cowan and Steel, 1974).
3.7 GRAM STAINING
A smear of colonies isolated was made on a glass slide using wire loop. It was dried and heat
fixed. Then, the fixed smear was flooded with crystal violet solution for 30seconds and washed.
This was later tipped off and covered with lugo’s lodine for 60 seconds. This was then washed
off and decolorized with ethanol 70%. The smear was then flooded with safranin solution for 60
seconds and then rinsed with water and air dried (Cowan and Steel, 1974).
3.8 MICROSCOPY
The back of the glass slide was wiped clean and a drop of colourless thick oil (glycerin)
was applied on the smear which was examined microscopically with x100 objectives for the
observation of grams reactions and morphological characteristics of the bacteria cell. Positive
bacteria did not decolourized with ethanol and hence their cells appear purple in colour, while
gram negative cells retained the counter staining colour of safranin and hence appear pink in
colour (Cheesbrough, 2000).
9
3.9 BIOCHEMICAL REACTIONS.
3.9.1 TRIPLE SUGAR IRON (TSI) MEDIUM
About 65g of triple sugar iron was weighted and dissolved in one liter of distilled water; it was
heated on the hot plate to achieved completed dissolution. 10ml of it was transferred into test
tube, the test tube were corked with cotton wool and aluminum foil and then sterilized by
autoclaving at 121 for 15minute (Cowan and Steel, 1974).
3.9.2 KOSERS CITRATE MEDIUM
About 25g of
sodium citrate, 1.5g of sodium ammonium phosphate, 0.2g 0f mangnessim
sulphate, 1g of potassim dehydrogen and 0.06g of bromothymol blue were dissolved in one litre
of distilled water and heated on the hot plate for complete dissolution. It was dispensed in the test
tube plugged with cotton wool and aluminum foil and sterilized at 121 for 15minuted
(Cheesbrough, 2000)
3.9.3 UREA MEDIUM
About 25.2g of the urea base was weighted and dissolved in one liter of distilled water. The
mixture was heated to achieve total dissolution before it was dispensed in universal bottle and
was autoclave at 121 for 15minutes, 5ml of 40% urea solution was aseptically introduced into the
media. This was allowed to solidly in a slanting position (Cowan and Steel, 1974).
3.9.4 CATALASE TEST
10
This test was carried out mostly on gram-positive cocci to test their ability to produce the
enzyme catalases. In this case, it differentiates between Staphylococcus is catalase positive and
Streptococcus is catalases negative. Catalase test is carried out also in both gram-possitive and
gram negative bacilli and cocci. A colony of culture was emulsified in a drop of hydrogen
peroxide on a clean glass slide. The presence of oxygen bubbles indicates a positive result of a
catalase test while; the absence of oxygen bubbles indicates a negative result of a catalase test
(Cheesbrough, 2000).
3.9.5 COAGULASE TEST
This test is used to differentiate between Staphylococcus aureus from other Stahpylococcus
species, due to their education of the enzyme coagulase by the S. aureus only. A looped of the
isolated was emulsified in a drop of normal saline and a drop of citrated plasma was added and
mixed. The slide was rocked gently for 2 minutes observing for coagulate reaction or dumping
positive isolates gave agglutination reaction with the plasma (Manga and Oyeleke, 2008)
3.9.6 SUGAR FARMENTATION TEST
An old culture was stabbed into a sterile triple sugar ion Agar slant (TSI) in a test tube and
incubated at 37°c for 24hours. It was then observed for glucose, lactose, sucrose, gas production
and motility. In positive test, glucose was indicated by redness of the bottom of the test tube,
while in lactose, the media appeared yellow. For motility in the of stabbation of medium, would
not be sharply define and the rest of the medium would be cloudy. (Cheesbrough, 2000)
11
3.9.7 UREASE TEST
Urease test is applied for bacteria species that can decompose urea by enzymatic reaction to
produce ammonia. After solidification of the urea medium, the inoculums was inoculated into
the slant bottles and incubated at 37°c for 24 hours. Positive test is indicated by purple pink
colour and for negative test there is no change (Cowan and Steel, 1974).
3.9.8 CITRATE TEST
Koser’s citrates medium was inoculated with the isolated and incubated at 37°c for 48hours. It
was examined after two days. The presence of growth lead to increase in pH resulting in the
change in coloure table for positive test and initial green colour for negative test (Cowan and
Steel, 1974).
3.9.9 INDOLE TEST
Colonies were picked and inoculated into the test tube containing the indole medium and finally
incubated at 37°c for 48hours. Sometime 96hours at 37°c may be required. 0.5ml of kovac’s
reagent was added drop wise to the test tubes and was shake gently. This production of indole is
confirmed by the formation of red ring colorations on the surface of the medium, which indicate
positive reaction while; in negative reaction red colorations is not produced. (Cheesbrough,
2000).
3.9.10 HYDROGEN SULPHATE TEST (H2S).
The prepared test medium was used to determine the production of H2S from different test
organisms. Each test organism was inoculated into a test tube stabbing the medium. The test
12
tubes were then incubated for 24hours at 30oc. A black colour along the line of stabbing
indicated a positive reaction (Cowan and Steel, 1974).
3.9.11 METHYL RED (MR) TEST
A heavy inoculums of the test organism was inoculated into MR medium contained in each tube.
The test tubes were incubated at 37oc for 48 hours. After that, 5 drops of methyl red indicator
was added to the incubated test tube. An instant red colour signifies a positive test. The test is use
for bacteria that can decompose urea by enzymatic reaction to produce ammonia (Oyeleke and
Manga 2008).
3.9.12 VOGES PROKAUER (VP) TEST
Heavy inoculums of the test organism was inoculated into VP medium contained in different test
tube. They are then incubated at 37oc for 48 hours. After which 0.5ml of alpha nephtol was
added then follow by 0.5ml of 40 % KOH. It is then agitated and allowed stand for 30 minutes; a
red to pink colour signifies a positive test (Cowan and Steel, 1974).
13
CHAPTER FOUR
4.0 RESULT
Most of the notes were wrinkled and dirty; Out of the 26 currency notes on which bacteriological
analysis was conducted, 24 (92.3%) were found contaminated with various kinds of pathogenic
bacteria. Out of these 18 notes, bacterial concentration was found high on 10 notes (38.5%)
which were dirty /mutilated compared to 12 other notes (46.2%) that were categorized as clean.
No bacteria were found on the 2 notes considered as mint. The physical conditions of the various
notes are shown in Table 1. The bacterial counts were generally high: ranging from 2.0 × 103 to
1.0 × 104 cfu/cm2. The N20 and the N100 notes harbour the highest bacterial load (average of 1.0
× 104 cfu/cm2) while N5 notes had the least (2.0 × 103 cfu/cm2). Table 2 shows the average
bacterial counts obtained for each of the notes. Some bacteria are Gram positive while some are
Gram negative with various shapes. Microscopic identification of the bacteria isolate by using
gram stain reaction is shown in table 3. Table 4 shows the Biochemical test of bacteria
characterization,
eight
bacterial
species:
Escherichia
coli,
Staphylococcus
aureus,
Staphylococcus epidermidis, Streptococcus pyogenes, Enterobacter arogenes, Pseudomonas
aeroginosa and Bacillus subtilis were isolated. Bacteria isolated from different denominations of
the abused Naira notes are shown in Table 5. Figure 1 shows the occurence of the bacterial
isolates. Streptococcus pyogenes was the least encountered (4.2%) while S. aureus was the most
encountered (25%), while Figure 2 shows the level of bacterial contamination based on different
notes type.
14
Table 1.
Shows the physical conditions of a sample of each denominations. The result shows how
clean, dirty/mutilated and abused the notes were. The term clean describes notes that had a clean
appearance without any obvious damage. The term dirty/wrinkled 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.
15
Table 1. Physical conditions of a sample of each Naira denominations.
Denominations (Naira)
Condition
Mint
Clean and neat
5
Fairly clean and wrinkle
10
Dirty, wrinkle and odorous
20
Dirty, toured, wrinkle and odorous
50
Dirty and wrinkle
100
Dirty, wrinkle and odorous
200
Fairly dirty, wrinkle and odorous
500
Fairly dirty and wrinkle
1000
Fairly dirty and wrinkle
16
Table 2.
Shows the average bacterial count of different denominations. The result shows that the
bacterial counts were generally high: ranging from 2.0 × 103 to 1.0 × 104 cfu/cm2. The N20 and
the N100 notes harbour the highest bacterial load (average of 1.0 × 104 cfu/cm2) while N5 notes
had the least (2.0 × 103 cfu/cm2)
17
Table 2. Average bacterial count of different denominations.
Bacterial count ( cfu/cm3 )
Denominations (Naira)
5
2.0×103
10
4.0×103
20
1.0×104
50
4.0×103
100
1.0×104
200
4.0×103
500
6.0×103
1000
4.0×103
18
Table 3.
Shows the microscopic Identification of the bacteria isolate by using gram stain Reaction.
The result shows the microscopic arrangement and the shape (morphological structure) of every
isolate which are categorized to eight (8) and their reaction toward grams staining.
19
Table 3. Microscopic Identification of the bacteria isolate by using gram stain Reaction.
Sample of
the isolate used
Microscopic arrangement
and shape of the isolate
Gram Reaction
A
Long rod disperse
+
B
Cocci in chain
+
C
Cocci in chain
+
D
Cocci in pair
+
E
Cocci in chain
–
F
Long rod in chain
–
G
Cocci in chain
–
Key: + = Positive;
- = Negative.
20
Table 4.
Shows the biochemical test of bacterial characterization. The result showed the ability
and inability of these bacterial to catalyze on certain substrate. Some bacteria are Gram positive
while some are Gram negative with various shapes. There bacteria are identified isolates that
occur on money.
21
Table 4. Biochemical test for identification of bacterial
Sample Ca
Co
La
Gl
Su
H 2S
Gas Mo
A
+
-
+
+
+
B
+
-
+
+
+
C
+
+
+
+
D
+
-
-
+
E
+
+
+
+
+
+
-
+
+
F
-
-
+
+
+
-
-
+
G
+
-
-
+
-
-
-
+
-
In
Ur MR
VP Ci
Organism
+
+
-
-
-
+
+
Bacillus subtilis
-
+
-
-
-
+
-
+
Streptococcus progenes
+
-
-
-
-
+
-
+
-
Staphylococcus aeureus
+
-
+
-
+
+
-
+
- Staphylococcus epidermidis
+
+
-
-
-
+
-
-
-
+
Pseudomonas aeroginosa
-
+
Enterobacter aerogenes
+
-
Escherichia coli
Key: Ca = Catalase; Co = Coagulase; La = Lactaose fermentation; Gl = Glucose; Su = Sucrose;
Mo=Motility; In = Indole; Ur = Urease; MR = Methyl Red Test; VP = Voges Prokauer
Test; + = positive; - = Negative.
22
Table 5.
Shows the bacterial isolated from Naira notes in circulation in Sokoto. This table shows
the type and numbers of isolate from each denomination both in figure and in percentages. Out
of 24 (excluding the 2 mints), 22 Naira notes were found to be contaminated by one bacterial or
the other. N20 and N100 notes harbour the highest bacterial load 5(22.7%) while N5 notes had
the least 1(4.6%).
23
Table 5. The bacterial isolated from Naira notes in circulation in Sokoto.
Naira No.
Note Sampled
Escherichia Staphylococcus Staphylococcus Streptococcus Enterobacter Pseudomonas Bacillus
coli
aureus
epidermidis
progenies
aerogenes
aeroginosa
sutilis
Total
5
3
0(0)
0(0)
0(0)
0(0)
1(33.3)
0(0)
0(0)
1(4.6)
10
3
0(0)
1(33.3)
0(0)
0(0)
0(0)
0(0)
1(33.3)
2(9.1)
20
3
1(33.3)
1(33.3)
0(0)
1(33.3)
0(0)
2(66.7)
0(0)
5(22.7)
50
3
0(0)
0(0)
1(33.3)
0(0)
0(0)
0(0)
1(33.3)
2(9.1)
100
3
1(33.3)
2(66.7)
1(33.3)
0(0)
0(0)
0(0)
1(33.3)
5(22.7)
200
3
1(33.3)
0(0)
0(0)
0(0)
0(0)
1(33.3)
0(0)
2(9.1)
500
3
0(0)
2(66.7)
0(0)
0(0)
0(0)
0(0)
1(33.3)
3(13.6)
1000
3
0(0)
0(0)
1(33.3)
0(0)
1(33.3)
0(0)
0(0)
2(9.1)
Total
24
3(12.5)
6(25)
3(12.5)
1(4.2)
2(8.3)
3(12.5)
4(16.7)
22(100)
24
Figure 1.
Shows the occurrences of bacterial isolates. It characterized the Prevalence of bacteria
isolated from different denominations (n = 24) of the abused Naira notes. Streptococcus
pyogenes was the least encountered (4.2%) while S. aureus was the most encountered (25%).
25
Figure 1. The occurrences of bacterial isolates.
30
25
% Prevalence
20
15
10
Series 1
5
0
Bacteria isolates
26
Figure 2. Shows the level of bacterial contamination on different type of notes i.e polymer note
and paper note. There is high concentration of bacteria on paper notes as compare with the
polymer notes.
27
Figure 2. bacterial contamination on different type of notes.
45%
polymer notes
paper notes
55%
Fig. 2; level of bacterial contamination based on different notes type
28
CHAPTER FIVE
5.1 DISCUSSION
The isolation of bacterial agents from currency notes in the study reported here confirmed that
money might be a vector playing an important role in the transmission of bacterial infection 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).
Escherichia coli, Enterobacter spp and Staphylococcus epidermidis are usually nonpathogenic
but some strains can cause serious food poisoning in humans and urinary tract infections.
Similarly, S. epidermidis is usually non-pathogenic but it is an important cause of infection in
patients whose immune system is compromised. Other bacteria are pathogenic that can cause
various diseases ranging from opportunistic infections in skin and other tissues to pneumonia and
Toxic Shock Syndrome (TSS). Among the pathogenic bacteria isolated, E. aerogenes is a
nosocomial and pathogenic bacterium that causes opportunistic infections in skin and other
tissues.
S. aureus can cause a range of illnesses from minor skin infections, such as pimples, impetigo
boils, and abscesses, to life-threatening diseases, such as pneumonia, meningitis, osteomyelitis
endocarditic, TSS and septicemia.
The study revealed prevalence of bacteria in paper notes which was not unexpected. Pope
and co-worker (2002) demonstrated in their study in western Ohio that bacteria were capable of
29
growing on currency notes. 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).
This study revealed a significant association between bacterial contamination and the
condition of the currency, with higher rates of bacterial 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 1991, Gwatkin 2000). Risk of infection is increased several fold 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.
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
30
Nigeria 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
could elevate their contributory role in transmission of some pathogens, thereby constituting
potential public health hazard. Different species of bacteria isolated on this study are similar to
those studied by Khin Nwe and co-workers (1989) in Rangoon, Myanmar; Goktas and Oktay
(1992) in Turkey; and Pope and co-workers (2002) in Ohio. All of these researchers strongly
suggested that money plays a role in the transmission of potentially harmful bacteria agents.
Bacteria isolated in those studies, such as coagulase-negative Staphylococcus, alpha-hemolytic
Streptococcus, Enterobacter species, non-aeruginosa species of Pseudomonas, Bacillus species
and Escherichia spp, do not typically cause infections in healthy people rather they have been
known to cause significant infections in those with depressed immune systems, including those
infected with HIV, undergoing cancer chemotherapy, or taking other medications that depress
the immune system. Those bacteria may also cause infection in hospitalized patients (Emori &
Gaynes 1993).
The study reported here found relatively more prevalence of bacteria among lowerdenomination 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) reported that a foreign bank wins business by guaranteeing its customers with a
31
steady supply of fresh, new currency notes. This practice may not guarantee the absence of
microbial contamination, but it could minimize the risk of currency-associated infection.
A significant association was established between contamination and sources of currency
(Conductors, Butchers, food sellers and banks in this study), with the highest levels of
contamination found among currency notes from conductors of minibuses, followed by butchers
to food sellers. Khin and co-authors (1989) isolated high levels of enteric pathogens from papermoney samples obtained from butchers and fish mongers in a local market in Sokoto. 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 countries, are witnessing an influx of child labors. Most of these
individuals searching for the unskilled job especially hanging on the doors of buses and live
under severely unhygienic conditions, appear sick, and sometimes have putrefying sores on their
bodies. It was not surprising that money obtained from them were highly contaminated.
Inability to quantify the cell numbers of the bacterial agents and failure to take into
account the possible presence of other categories of potential pathogens, such as viruses and
fungi that might contaminate currency notes are some of the limitations observed in this study,
which may be the work for future research. Furthermore, we could not confirm that the identified
pathogens could be transmitted from person to person because of the exchange of money. We
could only recommend that the paper notes used in this country are more vulnerable for the
transmission of bacterial diseases and more complex study be undertaken, using molecular
biology tools, to achieve and confirm their level of vulnerability.
32
5.1 CONCLUSIONS
The results of the study reported here suggest that money might be a possible vehicle of
bacterial infection especially the paper currency. There is high acceptability of polymer notes as
compare with the paper notes.
5.2 RECOMMENDATION
Handling of money deserves special attention. 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 pathogens. 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 2000). Other
recommendations are the washing hands thoroughly by food handlers, whether at a restaurant or
at home; after handling currency and before handling food, 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, we recommend that similar studies on the microbial contamination of
33
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.
34
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