BA 625 Assignment 1-4
Liberty University
Master of Public Health
Health 625
Prevention and Control of Infectious Diseases
STUDYING RISK FACTORS ASSOCIATED WITH HUMAN LEPTOSPIROSIS (Kamath R et al.):
AN ARTICLE REVIEW
IMA STUDENT
ID: XOXOXO
November 4, 2014
Words: 951
Article: Kamath R, Swain S, Nair SN, Pattanshetty S. Studying risk factors associated with human Leptospirosis. J Glob Infect Dis.2014; 6(1): 3–9. doi:10.4103/0974-777X.127941.
I. SUMMARY
The article presents the findings of a matched case-control study conducted to identify the occupational and environmental risk factors of Leptospirosis in India. The study was conducted from April 2012 to August 2012 with a total of 70 cases and 140 sex matched controls belonging to the same neighborhoods as cases.
Data collection on occupational and environmental risk factors was achieved through semi-structured questionnaires and researcher observation.
The study revealed that certain occupational and environmental factors were significantly associated with Leptospirosis and were therefore risk factors for this disease. Of all risk factors, the presence of a wound or cut in the skin while working was found to have the strongest association with Leptospirosis. This was followed by contact with soil contaminated with infected rodent urine. Occupations involving outdoor activities were significant risk factors for Leptospirosis compared to those involving indoor tasks. Other significant risk factors were the presence of drainage or sewage within a 15m radius from the home as well as the ingestion of inadequately cooked or raw vegetables with rat bites.
II. ARTICLE REVIEW
This article review examines the research methodology, study findings as well as the limitations of the study. Findings are analyzed using evidence from similar studies and recommendations are provided to address the identified limitations.
Review of Methodology
The case-control approach was used to determine risk factors of Leptospirosis. While this method is not very rigorous compared to other study designs, it is useful in the study of outbreaks and rare or neglected diseases such as Leptospirosis. This method is also appropriate where the small sample size and inadequate resources limit the use of more rigorous designs.
The control of confounders was achieved by matching cases and controls according to gender, age and geographic location. 1 While researchers identified the three main confounders, confounding by religion was not controlled, in fact majority of participants belonged to one religion. This may have been a result of selecting cases and controls from the same neighborhood. Religion may be a risk factor of Leptospirosis especially if it involves rituals or practices where members come in contact with contaminated rivers, water or soil.
Data collection was done through the use of semi-structured questionnaires and researcher observation. 1 While semi-structured questionnaires allow researchers to obtain substantial information, they are prone to researcher bias during analysis and are therefore less reliable. Data collection through observation introduces bias especially when each observation involves a single researcher. Using more than one researcher for each observation may help minimize bias.
Exposure to risk factors was determined retrospectively thus increasing the possibility of recall bias.
Review of Findings
The study identified the occupational and environmental factors that were significantly associated with Leptospirosis. Of all risk factors identified, the presence of a wound or cut in the skin during work had the strongest association with Leptospirosis.1 A similar observation was made in a systematic review of risk factors of Leptospirosis which indicated that skin wounds were significantly associated with Leptospirosis infection.2 Contact with soil contaminated with rodent urine was also determined to be significantly associated with Leptospirosis infection.1 This is consistent with findings from other studies that have reported an increased incidence of Leptospirosis in individuals who have contact with contaminated soil or mud when farming without protective equipment.2,3,4,
In addition to the two significant findings described above, outdoor activities were significant risk factors for Leptospirosis. Occupations involving contact with mud, water, rivers and domestic animals were significantly associated with Leptospirosis.1 Other studies found that rural based occupations, water recreation activities and outdoor activities such as agriculture, farming and fishing significantly increased exposure to contaminated water and soil thus placing individuals at high risk for Leptospirosis.2, 3,4,5 The risk is even higher for individuals working with wounds or cuts or for those without protective equipment such as gloves and boots.1,2,4
It was further observed that the presence of drainage within a 15m radius from the home significantly contributed to the incidence of Leptospirosis.1 Other studies have linked the presence of stagnant waters and flooding to Leptospirosis infection.2, 4,5,6
Though not reported by previous studies, the ingestion of raw or inadequately cooked vegetables with rodent bites was significantly associated with Leptospirosis.1
A secondary observation made in this study and similar studies was that individuals in the productive age group (21-50 years old) were more likely to be exposed to contaminated water or soil and to subsequently become infected with Leptospirosis.1, 5 These individuals are more likely to be involved in high risk occupations such as agriculture, fishing or farming where they are frequently exposed to contaminated water or soil.6
Recommendations
The study was successful in achieving its objective of identifying the risk factors of Leptospirosis. The following recommendations serve as a guide for future research on this topic.
Since ethical constraints may limit the use of intervention studies, meta-analyses or systematic reviews and cohort studies are useful methodologies for future research. This case-control study can be replicated in different settings using a larger sample. It is important to assign more than one control to each identified case to reduce confounding; controls may come from different geographical locations.
Data requiring observation should be collected by more than one individual in order to minimize bias. Researchers may use a standardized form or checklist to record their observations.
Findings from this study demonstrate the importance of using protective equipment when performing high-risk tasks. This suggests the need for policymakers and Public Health professionals to develop guidelines that protect individuals at high risk for Leptospirosis. Policymakers may consider establishing regular screening and prophylaxis for individuals with high-risk occupations. Health education on environmental sanitation, vector control and personal hygiene is also important to minimize exposure to contaminated water and soil.
References
1. Kamath R, Swain S, Nair SN, Pattanshetty S. Studying risk factors associated with human Leptospirosis. J Glob Infect Dis.2014; 6(1): 3–9. doi:10.4103/0974-777X.127941
2. Sakundarno M, Bertolatti D, Maycock B. et al. Risk factors for Leptospirosis infection in humans and implications for public health intervention in Indonesia and the Asia-Pacific region. Asia Pac J Public Health. 2014;26(1):15-32. doi:10.1177/1010539513498768
3. Rafizah AA, Aziah BD, Azwany YN et al.Risk factors of leptospirosis among febrile hospital admissions in northeastern Malaysia. Prev Med. 2013;57(1):S11-13. doi:10.1016/j.ypmed.2012.12.017
4. Prabhakaran SG, Shanmughapriya S, Dhanapaul S et al. Risk factors associated with rural and urban epidemics of leptospirosis in Tiruchirappalli District of Tamilnadu, India. J Public Health. 2014;22(4):323-333. doi:10.1007/s10389-014-0611-1.
5. Vanasco NB, Schmeling MF, Lottersberger J et al. Clinical characteristics and risk factors of human leptospirosis in Argentina (1999–2005). Acta Trop. 2008;107(3):255-8. doi:10.1016/j.actatropica.2008.06.007
6. Heymann DL. Control of Communicable Diseases Manual. Washington, DC: American Public Health Association; 2008:643-644.