Research Article

Risk Factors of Leptospirosis in Rice Cultivators as Compared to non Rice Cultivators in Punjab, Pakistan

Muhammad Athar Khan1, Muhammad Zahid Latif2*, Syed Amir Gilani3 and Ifrah Bukhari4

1Director University Institute of Public Health, The University of Lahore, Pakistan; 2Director, Department of Medical Education, Associate Professor of Community Medicine, Azra Naheed Medical College, The Superior University, Lahore, Pakistan; 3Dean, Faculty of Allied Health Sciences, The University of Lahore, Pakistan; 4Institute of Administrative Sciences University of Punjab, Lahore, Pakistan.

Received | March 22, 2017; Accepted | January 10, 2018; Published | December 24, 2017

*Correspondence | Dr. Muhammad Zahid Latif, Associate Professor of Community Medicine/ Director, DME, Azra Naheed Medical College, Lahore, The Superior University, Pakistan; Email: [email protected]

Citation | Khan, M.A., M.Z. Latif, S.A. Gilani and I. Bukhari. 2017. Risk Factors of Leptospirosis in Rice Cultivators as Compared to non Rice Cultivators in Punjab, Pakistan. Annals of King Edward Medical University, 23(4): 536-539.

DOI | http://dx.doi.org/10.21649/journal.akemu/2017/23.4.536.539

Keywords | Leptospirosis, Zoonotic diseases, Rice cultivators, Odds ratio, Seropositivity, Punjab

Introduction

Leptospirosis is a global zoonotic infectious disease having alarming public health concerns (1). The disease is caused by different types of Leptospira. Due to the complimentary circumstances Leptospirosisis more common in the developing countries(2). Wild and domestic animals serve as the reservoirs. This infection is transmitted through the urine of the animals and contaminate water and soil. The contaminated soil and water transmit infection of Leptospirosis to human beings (3).

Generally this is an occupation related disease and the victims belong to animal slaughtering, owners of pet shops, farm workers, handlers of meat, sewerage and agriculture workers (4). Leptospirosis affect multiple organs in human body and may lead to myocarditis, renal failure, respiratory distress and hypotension (5). This disease is an emerging infectious problem in many developing countries and is often endemic (6).

The dissemination of the organisms to human beings is also considered from the Rice field water mixed with the infected urine of rat(7). The organism penetrate the human host from the broken mucosa or skin and may lead to bacteremia/ septicemia. It multiplies mainly in the central nervous system, liver or kidneys. The organism persist in the kidney tubules and infective bacteria is shed in the urine. The disease is characterized by high grade fever, headache, arthralgia, myalgia, meningitis followed by jaundice and renal failure(8). Leptospira infection may remain asymptomatic or symptomatic depending upon the infecting type of the organism(9).

The workers of rice cultivation are exposed to water in the rice field which may be infected with the urine of rat. Due to this exposure these workers are at higher risk of disease development as compared to non cultivators of rice. Keeping in view the above mentioned scenario this study was planned and conducted to find out the strength of association of disease development among the rice cultivators and non cultivators.The objective was to quantify the risk factor of Leptospirosis in rice cultivators as compared to non rice cultivators in Punjab, Pakistan.

Materials and Method

After the approval of institutional ethical review board (IERB), 250 subjects were selected for this comparative cross sectional study, from five different rice growing districts of Punjab including Sahiwal, Okara, Narowal, Gujranwala and Sheikhupura. The farmers cultivating rice were included in the study where as the farmers not cultivating rice were excluded from the study. Multiple stage probability technique was used for sampling. In the first stage one union council was selected from district randomly. In the second stage, 25 subjects involved in rice cultivation from the last 10 years were selected from each union council. Similarly 25 subjects who never worked in the rice paddy field were also randomly selected from each union council as controls. This resulted in a total 125 adult males working in the rice paddy fields and matched 125 adult males who never worked in the rice paddy fields. A sample of 5 ml blood was drawn from each study subject through the adoption of standard procedure.Each serum sample was tested against each of the five antigens against the serovars i.e.’ Leptospirain terrogans varcanicola, grippotyphosa, hardgo, icterohaemorrhagiae and Pomona by the slide macro agglutination test (SMAT) as described by Lysons. The results were interpreted as negative in the absence of no agglutination, followed by mild agglutination and strong agglutination. The seropositive and seronegative results were compared and odds ratio was calculated to find out the strength of association among the exposed and non exposed.

Results

A total of 250 subjects were included in the study. Out of these, 125 subjects were exposed to the rice paddy water where as 125 were not exposed to rice paddy water. These study subjects were selected from five different rice cultivating districts of Punjab. The results of seropositivity and seronegativity among the exposed and non exposed are presented in Table 1. The cumulative seropositivity among the exposed is (83.2%) as compared to (42%) among the non exposed to rice paddy field water. The calculated cumulative odds ratio is 6.7 which represent a strong association of the risk for the development of disease among the exposed than the non exposed subjects. The seropositivity among the exposed is highest in Gujranwala district (92%) as compared to Okara (88%), Sahiwal (84%), Sheikhupura (83.2%) and Narowal (72%),

Table 1: Comparative seropositivity in rice cultivators and non rice cultivators of five districts in Punjab.

respectively. Similarly the calculated odds ratio reflect a very strong association among the exposed to rice paddy workers in Sheikhupura 16, Gujranwala 14.6, Okara 7.9 as compared toNarowal 3.9 and Sahiwal 3.5, respectively (Figure 1).

Discussion

Leptospirosis is a public health zoonotic disease which is widely present in tropical and sub tropical areas globally. It is a water borne problem prevalent in humid and hot climate of developing countries like Pakistan(10), (11). The contamination of water with the urine of rats, domestic and wild animals attributes to the burden of this disease (12). The cultivators or the workers of rice field paddy water usually stand for many hours in water for the implantation of rice in the mud field. This exposure of several hours is a strong risk factor among the exposed individuals for the development of disease. This case control study was planned and conducted to quantify this risk factor of Leptospirosis in rice cultivators as compared to non rice cultivatorsin Punjab, Pakistan. The quantification of the risk factor and its strength of association is presented in the forms of odds ratio. The results presented in Table 1 (odds ratio= 6.7) represent that there is a strong contribution of rice cultivation as a risk factor for Leptospirosis. These results are consistent with the finding of another study conducted by Syed Muhammad Ali in South West Iran which concluded that the farmers of rice cultivation are more significantly infected with Leptospirosis as compared to other residents of the rural areas (13). Similarly, it was found in another study in Srilanka that the rice farming activities are the strongest exposure risk factor associated with Leptospirosis(14).

Conclusion

Leptospirosis is a public health zoonotic disease which is widely present in tropical and sub tropical areas. This study concludes that there is a strong association of rice cultivation with Leptospirosis. It is recommended that rice cultivators should protect their body parts with gloves or boots as prevention is the most appropriate way to control any disease.

Authors Contribution

Muhammad Athar Khan: Research design, article review, corrections and finalization.

Muhammad Zahid Latif: Review of literature, article writing and data analysis.

Syed Amir Gilani: Data collection and data analysis.

Ifrah Bukhari: Data entry and analysis.

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