Study of Parasitic Pathogens on Nigerian Currency Circulating in Selected Markets in Lafia Metropolis, Nasarawa State, Nigeria

Money is the most widely handled article throughout the world, it goes through clean and dirty hands and can get contaminated with parasites and pathogens. Thus, the study on parasites associated with circulating Naira notes in selected markets in Lafia metropolis, Nasarawa State, Nigeria was carried out from June, 2019 to March, 2020. A total of three hundred and twenty (320) samples of Nigerian Naira notes consisting of forty (40) pieces of each denomination was used for this study. Market samples were collected from food vendors, fish sellers, butchers, hawkers and fruits/vegetable sellers and then screened. Out of the 320 samples examined, 32 (10.00%) were contaminated with parasite species that spread across Ascaris lumbricoides 6 (1.88%), Entamoeba histolytica 7 (2.19%), hookworm 10 (3.13%), Taenia spp. 1 (0.31%) and Trichuris trichiura 8 (2.50%). The mint Naira notes had no parasitic contamination. The level of parasitic contamination of Naira notes in relation to currency sources, and as well as the physical conditions of the notesshowed a very high significant difference (P <0.001). Also, parasitic contamination in relation to Naira notes denominations showed a very high significant difference (P < 0.001). Only the paper notes were contaminated with human pathogenic parasites while polymer notes were parasite free. In conclusion, this is the first study in Lafia, Nasarawa State that showed that the Nigerian currency notes in circulation within the metropolis are contaminated with five parasite species that are known to be pathogenic to humans. Also, the handlers of such Naira notes may possibly stand a chance of being infected with the parasites recorded if their hands are not properly washed and sanitized after transactions.

Introduction seen faded, torn, stapled, cello taped, squeezed and with writings on them. Being the most frequently passed item in the world it should not come as a surprise as these currency notes are usually contaminated with various pathogens and parasitic organisms as it is handled by persons of varying health and hygienic standards and is stored under varying environmental and personal hygienic conditions [11]. Awodi et al. [12] reported that the major source of currency contamination in Nigeria could be as a result of poor or negative money handling practices like spraying during ceremonies, here the notes are sprayed on the celebrant(s) and in the process fall on the ground where a large number of people dancing, step on them with soiled shoes which are often contaminated with parasites or pathogens.
Parasites that have been observed to be contaminants of the naira notes are mainly of faecal origin [12]. Generally, lack of personal hygiene is one of the common ways to contaminate the currency notes with parasitic pathogens. Unhygienic habit such as improperly washing of hands after visiting the toilets as well as the habit of wetting fingers with saliva during money counting to a greater extend leads to the contamination of these currency notes with cysts, eggs and larvae of pathogenic parasites [3][4][5][6][7][8][9][10].
In view of the above, the study aimed at isolating and identifying parasitic pathogens contaminating circulating Nigerian naira notes in selected markets in Lafia metropolis, Nasarawa State, Nigeria.

Study Area
The study was carried out in Lafia metropolis, Nasarawa State,  [14]. Lafia serves as a higher-order city in the provision of consumer goods and other services to the immediate smaller towns that are directly linked to it. A number of banks including first and second generation banks are operational in the city as business activities are high.

Collection of Samples
A total of three hundred and eighty-four (320) samples of Nigerian currency notes consisting of forty-eight (40) pieces of each naira note denominations (₦5, ₦10, ₦20, ₦50, ₦100, ₦200, ₦500, and ₦1000) of both polymer and paper were randomly collected for the purpose of this research from June 2019 to March 2020. Verbal consent of the participants was obtained before the collection and exchange of the notes. Naira notes were collected from two (2) markets (Lafia modern market, and Alamis market) selected within Lafia metropolis. In the market, samples were collected from food vendors, fish sellers, butchers, hawkers, fruits and vegetable sellers. The naira notes were collected aseptically, kept separately in a labelled sterile polythene bags and conveyed to the Department of Zoology laboratory of the Federal University of Lafia for screening. The notes were grouped as follows: Mints, dirty, very dirty and mutilated dirty. The mints notes served as control.

Parasitological Screening
The parasitological screening was carried out according to the methods outlined by Leonard and Olajumoke [7] and Ahmed and Mujittapha [8].

Statistical Analysis
Data obtained were analysed using R Console software (Version 3.2.2). Pearson's Chi-square test was used to compare prevalence rate between species of parasites. Also, prevalence of parasites in relation to currency denominations, currency sources and as well as the physical conditions of the currency was compared using Pearson's Chi-square test. Level of significance was set at P < 0.05.

Prevalence of Parasites in Relation to Currency Physical Conditions
From (Table 2), no parasites were found to contaminate the mint (control) Naira notes. However, very dirty Naira notes had the highest parasitic contamination of 13 (16.25%) followed by the mutilated dirty notes 11 (13.75%) and dirty naira notes 8 (10.00%). Therefore, there was a high significant difference (χ² = 15.312, df = 3, P = 0.001568) in the parasitic contamination of Naira notes in relation to physical conditions.

Prevalence of Parasites in Relation to Currency Sources
Naira notes collected from butchers had the highest prevalence of parasitic contamination 11 (17.19%) followed by food vendors 9 (14.06%), fish sellers 8 (12.50%) hawkers 3 (4.69%) while those from fruits and vegetable sellers 1 (1.56%) had the least parasitic contamination (Table 4). Therefore, there was a high significant difference (χ² = 17.386, df = 4, P = 0.001626) in the level of contamination of the Naira notes in relation to currency sources. the Naira currency notes probably due to high chances of the notes falling on the ground surface and as well as the possibility of users using soiled hands to handle these notes. Correspondingly, studies on parasites, cyst and egg on the Nigerian currency by Ombugadu et al. [20] indicated that hookworm was the most prevalent parasites screened from currency notes sourced within Keffi metropolis, Nasarawa State.
The very dirty notes were the most contaminated with parasites probably due to the fact that they had been in circulation for long and exchanged hands more frequently thus exposed to contamination. This agrees with findings of Ahmed and Mujittapha [7], Simon-oke and Ajileye [19] and Ombugadu et al. [20] who reported that the very dirty notes collected from Katsina, Akure and Keffi metropolis were the most contaminated with parasites.
However, this is contrary to the finding of George and Ifenyinwa [21] in a study in Akure metropolis who reported that the dirty notes were the most contaminated with parasitic contaminants.
The ₦100 denomination notes were the most contaminated with parasites possibly due to the fact that it is commonly at the reach of most people at the lower income group in the populace than the ₦1000-notes. This implies that the ₦100 denomination passes more hands and gets contaminated in the process than the ₦1000 notes which is not handled by many people. This finding is in agreement with the reports of earlier works of Leonard and Olajumoke [8] and Simon-oke and Ajileye [19] who found that the ₦100 notes carried more contaminants. On the other hand, the present observation does not agree with the finding of Ahmed and Mujittapha [7] who noted that the ₦200 denomination notes were the most contaminated.
From this study, it was observed that a number of the paper notes were contaminated with parasites whereas the polymer notes were parasite free. This may be as a result of the rough surface of the paper notes which probably promotes a good attachment area for the parasites whereas polymer notes has a smooth and slippery surface which will not support adherence of the parasites. El-Dars and Hassan [22] had opined that paper notes which are made of 75% cotton and 25% linen offer large surface area for pathogen attachment. Also, Dehghani et al. [23] reported that the degree of contamination is dependent on the texture of the currency. Similarly, this observation is in agreement with Leonard and Olajumoke [8] who recorded parasites on paper notes while none was found on polymer notes screened. On the contrary, the findings of Ahmed and Mujittapha [7], Ombugadu et al. [20] and Simon-oke and Ajileye [19] recorded high parasites prevalence in polymer notes.

Conclusion
Findings from this study have shown that circulating Naira notes in Lafia metropolis were contaminated irrespective of currency sources and notes types. With the exception of mints, the physical conditions of all other Naira notes accommodate parasites on them. Paper notes harbor parasites while no polymer note was contaminated. The ₦100 notes were the most contaminated denomination of the Naira notes screened. It is therefore recommended that public health education and awareness campaign to the populace of Lafia metropolis should be carried out focusing on the health benefits of good personal hygiene and the high possibility of acquiring infections while handling Naira notes. Also, the change of paper notes denominations (₦100, ₦200, ₦500, ₦1000) into polymer notes will drastically reduce the prevalence rate of parasites in Naira notes. Food vendors should have separate cashier that strictly handle collection of funds so as to reduce chances of the falling off of parasites into food being served to consumers in the process of collection of Naira notes if the individual dishing out the food is simultaneously the cashier.