Annals of Tropical Medicine and Public Health
Home About us Ahead Of Print Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online:34
  Print this page  Email this page Small font sizeDefault font sizeIncrease font size
 


 
Table of Contents   
ORIGINAL ARTICLE  
Year : 2011  |  Volume : 4  |  Issue : 2  |  Page : 86-90
Seroprevalence of Hepatitis B, Hepatitis C, and human immunodeficiency virus among healthy voluntary first-time blood donors in Kolkata


Department of Medicine, Institute of Post Graduate Medical Education and Research/SSKM Hospital, West Bengal, Kolkata - 700 020, India

Click here for correspondence address and email

Date of Web Publication8-Oct-2011
 

   Abstract 

Background: Transfusion transmitted infections (TTIs) threaten safety of the recipients and the community as a whole and are a subject of real concern worldwide. Aims and Objectives: To know prevalence of Hepatitis-B (HBV), Hepatitis-C (HCV), and Human immunodeficiency virus (HIV) in voluntary first-time blood donors. Design and Setting: Cross-sectional observational study done in a teaching hospital. Materials and Methods: A total of 3 745 voluntary first-time blood donors were recruited and tested for HBV, HCV, and HIV with Enzyme-linked immunosorbent assay (ELISA). Results and Analysis: Among 3 745 blood donors, majority (90.95%) were male and 18 to 39 years age group. Prevalence of HBV was higher than HCV and HIV. HBV was maximum in 40 to 49 years (2.25%) and 18 to 29 years (1.86%) age group, whereas HCV and HIV were maximum in >50 years age group (0.93% and 1.86%, respectively). HIV positivity showed increasing prevalence with increase in age. Statistical Analysis: Statistical analysis was done using %, Chi square test, and Chi square for trend analysis. Conclusion: Seroprevalence of HBV, HCV, and HIV in voluntary blood donors is high in Kolkata and is high throughout this decade. Prevalence is even higher in other parts of India and Indian subcontinent. As voluntary blood donations are the major source of blood supply, chance of TTIs are very high in this part of the world.

Keywords: Blood Donors, Hepatitis-B, Hepatitis-C, Human Immunodeficiency Virus, Seroprevalence, Transfusion Transmitted Infections

How to cite this article:
Das B K, Gayen B K, Aditya S, Chakrovorty SK, Datta P K, Joseph A. Seroprevalence of Hepatitis B, Hepatitis C, and human immunodeficiency virus among healthy voluntary first-time blood donors in Kolkata. Ann Trop Med Public Health 2011;4:86-90

How to cite this URL:
Das B K, Gayen B K, Aditya S, Chakrovorty SK, Datta P K, Joseph A. Seroprevalence of Hepatitis B, Hepatitis C, and human immunodeficiency virus among healthy voluntary first-time blood donors in Kolkata. Ann Trop Med Public Health [serial online] 2011 [cited 2014 Apr 24];4:86-90. Available from: http://www.atmph.org/text.asp?2011/4/2/86/85758

   Introduction Top


Transfusion transmitted AIDS in mid-1980s raised the question of blood safety. As transfusion of whole blood or its components is an integral part of medical or surgical management and carries the risk of transmitting transfusion transmitted infections (TTIs) like hepatitis, Human immunodeficiency virus (HIV), syphilis, malaria, toxoplasmosis,  Brucellosis More Details, and some other viral infections like cytomegalovirus, Epstein-Barr virus Herpes, and west Nile virus from donors to the recipients, efforts are being made worldwide to provide zero-risk transfusion. Among the TTIs, hepatitis B (HBV), hepatitis C (HCV), and HIV are the most dreadful. It is unlikely that any single test or combination of tests will be 100% effective in detecting window period infections caused by them and repeat donation increases the risk of transfusion transmission as seroconversions assumed to occur at the midpoint between a donor's last seronegative donation and the first seropositive donation. [1] Near about 2 billion people have been infected with HBV and 360 million have chronic infection worldwide and it is the 10 th leading cause of death worldwide causing 500 000 to 1.2 million deaths per year due to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. [2],[3] In Asia and most of Africa, chronic HBV infection is common and in Western countries, the disease is relatively rare. [3] Nearly 3.9 million people are estimated to be infected with HCV, the most common chronic blood-borne infection, leading to 8 000 to 10 000 deaths annually in USA. [4] On top of these two, HIV has become a major problem to mankind and its prevalence and incidence is increasing day by day. At the end of 2007, 33.2 million individuals were living with HIV infection (range: 30.6 - 36.1 million) according to the Joint United Nations Programme on HIV/AIDS (UNAIDS). All of them are causing significant global health problem with serious mortality, morbidity, and financial burden.

India is the second most populous nation in the world. The Indian subcontinent is classified as an intermediate HBV endemic (HBsAg carriage 2-7%) zone and has the second largest global pool of chronic HBV infections. [3] India has a population of more than 1.2 billion with 5.7 (reduced to 2.5) million HIV-, 43 million HBV-, and 15 million HCV-infected persons and the risk of transfusion transmission of these viruses may be alarming due to high seroprevalence of anti-HIV-1, anti-HCV, and HBsAg (0.5%, 0.4%, and 1.4%, respectively) in blood donors. [5]

The aim of our study is to know the prevalence of HBV, HCV, and HIV in otherwise healthy voluntary first-time blood donors in the city of Kolkata, West Bengal. This knowledge might give us the idea of disease burden of the society and the basic epidemiology of these diseases in the community.


   Materials and Methods Top


This cross-sectional observational study was done among healthy voluntary first-time blood donors who attended blood bank or blood donation camps during the period of May 2009 to April 2010.

Inclusion criteria were as follows: (1) subjects of either sex, (2) age group (in years) - 18 to 60, and (3) subjects otherwise healthy for blood donation.

Exclusion criteria were as follows: (1) Subjects refusal, (2) fever at presentation, (3) pyrexia of unknown origin, (4) anorexia, (5) unexplained diarrhea, (6) unexplained weight loss, (7) history of gastrointestinal bleeding, (8) unexplained jaundice in recent past (within 6 month), (9) lymphadenopathy, (10) history of blood transfusion in the past, (11) history of MUSIC (multiple unprotected sexual intercourse), (12) history of IV drug abuse, and (13) history of blood donation in the past.

Procedure

Parameters to be studied were as follows:

  • Presence of HB s Ag in collected blood - with SD HbsAg ELISA 3.0 (STANDARD DIAGNOSTIC, INC).
  • Presence of anti-HCV Antibody in collected blood-tested with third-generation HCV Microlisa ELISA (J. Mitra and Co. Pvt. Ltd.)
  • HIV I and II rapid assay of collected blood with Microlisa ELISA (J. Mitra and Co. Pvt. Ltd.) (Counseled by VCCTC)


Strategy: The cases were identified by single test.

Statistical analysis

Statistical analysis was done using %, Chi square test, and Chi square for trend analysis. P value <0.05 was set as level of significance.


   Results Top


A total of 3 745 voluntary first-time blood donors were studied. Among them, majority, 3 406 (90.95%), were male and only 339 were female (9.05%). Among the three viruses, prevalence wise, HBV outnumbered the other two. Prevalence of HBV was 1.55%, whereas HCV and HIV were 0.35% and 0.32%, respectively. We did not find any statistically significant difference among male and female donors regarding prevalence of any of these three viruses [Table 1]. The study population was divided into four groups according to their age [Table 2] and found that most of the male donors were within 18 to 29 years age group, whereas maximum female donors were within 30 to 39 years age group.
Table 1: Prevalence of HBV, HCV, and HIV among male and female donors

Click here to view
Table 2: Age-wise distribution of male and female and prevalence of HBV, HCV, and HIV

Click here to view


Prevalence of HBV was maximum in 40 to 49 years (2.25%) age group, whereas HCV and HIV were maximum in >50 years age group.

Chi square for trend analysis of HIV positivity showed a statistically significant increasing prevalence with increase in age (Chi square for trend =5.841, P = 0.016). But analysis of HBV and HCV positivity across the age groups showed statistically insignificant trend (Chi square for trend =0.619, P = 0.431 and Chi square for trend =2.961, P = 0.85, respectively).


   Discussion Top


Human beings are the only reservoir of blood-borne viruses like HBV, HCV, and HIV and are of great concern because of their prolonged viremia and latent or carrier state. They are transmitted parenterally, vertically, or through high-risk sexual behaviors and can cause fatal acute and chronic life-threatening disorders. Blood transfusion is a potentially significant route of transmission of these TTIs. [6],[7] Hence, availability of safe blood for transfusion is a must for the recipients and the community as well and can be achieved by vigorous screening of donors and donated bloods. Blood donors from the community or the replacement donors in hospitals do not fall in the high-risk group like intravenous drug users, professional health workers, or sex workers. So, prevalence of HBV, HCV, and HIV among the healthy blood donors or the replacement donors reflects the disease prevalence in the community. It also estimates the risk of chance of acquisition of these infections during blood transfusion.

In India, carrier rate of HBV is near about 3%, and anti-HCV positivity presents in 1 to 1.5%. [8] There are 3.9 million HIV-positive people in India and more than 29 000 have AIDS. [9] So, the disease burden of these three infections is not negligible. All of them are associated with significant morbidity, mortality, and socioeconomic burden as well. [10] Due to limitation in current blood screening practices in developing countries, donation by such individual is a potential threat to recipients. [11] In India, detection of HBV infection among blood donors is carried out by HBsAg screening, while detection of anti-HBc is rarely done. [12] In West Bengal, mandatory HCV screening started from June 2001.

An increasing prevalence of HBV (1.28 - 1.66%), HCV (0.28 - 0.35%), and HIV (0.23 - 0.35%) was observed in blood donors of Kolkata in 2004 to 2005. [13] In the present study, HBV, HCV, and HIV (1.55%, 0.35%, and 0.32%, respectively) were maintaining nearly the same prevalence even in 2010. Majority of the donors were male (90.95%), similar findings were also found in studies in different parts of India. [14],[15],[16]

Major route of HBV transmission is parenteral and it is most infective among blood-borne viruses and chronic carrier state is associated with chronic liver disease, cirrhosis, and hepatocellular carcinoma. In developed country like USA, the risk of HBV transmission through blood transfusion is 1 : 63 000 units transfused. [1] Seroprevalence of HBV in other Indian studies had shown to range between 1.86 to 4.84%, which was much higher than the prevalence of the present study. [17],[18],[19],[20] An increasing incidence of HBV (2.6% in 2006, 2.67% in 2007, and 3.43% in 2008 and overall - 2.9%) was noted in blood donors of Bhopal. [21]

Voluntary blood donors of Chandigarh had 0.66% seropositivity of HBV. [22] Even the rural population of Ambajogai, India, had very high prevalence of HBV (4.84%), a matter of real concern. [20]

Transmission of HCV is primarily through blood exposure, and majority progresses to chronic infection and chance of cirrhosis and hepatocellular carcinoma is more than HBV. In USA, the risk estimate of HCV transmission is 1 : 103 000 per donor exposure and with mini pool-NAT (Nucleic Acid test) screening, the risk of HCV transmission will be as low as 1 in 2 million. [1],[23] In different Indian studies, HCV seroprevalence ranged between 0.57 to 1.49%, which was much higher than the present study (0.35%). [16],[17],[18],[21],[22]

India is the second largest home of HIV and has witnessed sharp increase in HIV/AIDS cases and transfusion-related HIV/AIDS has gone down from 16% - end November 1994 to 3% - end November 2002 due to compulsory blood screening for HIV for over a decade (national reports). From a window period donor, the risk of acquiring HIV based on HIV antibody testing has been reported to be 1 in 4 93 000 units transfused in the US. [1] The report of National AIDS control organization showed a considerable increase in HIV prevalence in the year 2005 in antenatal clinic (0.5 - 0.84%) and sexually transmitted diseases clinic (0.8 - 2.16%) from the state of West Bengal, whereas adult HIV prevalence in the rest of the country was comparable with the previous years. [24] Seropositivity for HIV (0.32%) in this study was lower than the studies reported from other parts of India. [25],[26],[27] Sonwane et al. showed 2.11% HIV prevalence in rural population of Ambajogai. [20] National data also suggest higher incidence of HIV in Chennai, Maharashtra, and South India. A slow and steady increase of HIV incidence in voluntary blood donors (from 1.6 per 1 000 in 1988-1989 to 3.8 per 1 000 in 1996-1997) was noted in Vellore. [15] An increase in HIV incidence from 0.04 to 0.55% was shown in New Delhi between 1989 and 1995, whereas a decreasing trend of HIV incidence (0.81% in 2006, 0.32% in 2007, and 0.53% in 2008, overall 0.51%) was noted in blood donors of Bhopal. [18],[21] Incidence of HIV (0.16-0.18%) in Kerala remained constant from 1990 to 1999. [16] In Chandigarh, HIV seroprevalence was 0.084%. [22] No voluntary blood donors were found to be HIV positive in Haryana. [28]

Different Asian countries had reported seropositivity in blood donors. Prevalence of HBV, HCV and HIV in North Pakistan was 0.82%, 2.46%, and zero% in voluntary nonremunerated blood donors. [29] Central Saudi Arabia had reported 1.5%, 0.4%, nd zero% HBV, HCV and retroviral infections with a tendency to increase with increase of age. [30] In Bangladesh, 1.39% were found positive for HBV, 0.024% were positive for anti-HCV, and 0.008% were positive for HIV in voluntary blood donors. [31] In Kathmandu, Nepal, seroprevalence of HIV, HBV, and HCV were observed to be 0.12%, 0.47%, and 0.64%, respectively. [32] Abdul Mujeeb et al. showed HBV, HCV, and HIV seroprevalence of 2.21%,0.5%, and zero% among college-going first-time blood donors in Pakistan. [33]

Developed countries like USA had reduced the risk of HIV-1, HCV to less than 1 per million through expanded donor screening criteria and through improvements and expansions of blood testing (Including minipool NAT) and achieved it at a cost exceeding $2 million and a cost-effectiveness far beyond accepted limits at $1.5 to $4 million per quality-adjusted life-year. [34] But the scenario is totally different in developing group of countries (DGCs) and least developed countries (LDCs) where usually insufficient and inadequate preparatory testing is a major weakness of safe blood supply. Only 66% of DGCs and 46% of LDCs screen all blood donations for HIV; 72% DGCs and 35% LDCs test all donations for HBV, and 71% and 48% for syphilis, despite improvements between 1988 and 1992, and are vulnerable of acquiring TTIs through blood transfusion. [35]


   Conclusion Top


Developing and least developed countries have their own limitations like poverty, poor education, ignorance, false belief, lack of uniform policy and policy implementation, and many others. Blood transfusion is a life-saving procedure and safety of blood and blood products are of utmost importance. Seroprevalence of HBV, HCV, and HIV in voluntary blood donors is high in this part of the globe. As NAT is costly and not cost effective, the safety of blood and blood products and reduction of TTIs in developing and least developed countries are in big question. It may be possible through proper donor selection and education, uniform implementation of laboratory screening tests and adequate supply of blood through voluntary blood donations along with restriction of repeat donation within short interval.

 
   References Top

1.Schreiber GB, Busch MP, Kleinman SH, Korelitz JJ. The risk of transfusion-transmitted viral infections. N Engl J Med 1996;334:1685-90.  Back to cited text no. 1
[PUBMED]  [FULLTEXT]  
2.Shepard CW, Simard EP, Finelli L, Fiore AE, Bell BP. Hepatitis B virus infection: Epidemiology and vaccination. Epidemiol Rev 2006;28:112-25.  Back to cited text no. 2
[PUBMED]  [FULLTEXT]  
3.Lavanchy D. Hepatitis B virus epidemiology, disease burden, treatment, and current and emerging prevention and control measures: A review. J Viral Hepat 2004,11:97-107.  Back to cited text no. 3
[PUBMED]  [FULLTEXT]  
4.Gasiorowicz M, Hurrie M, Russel A, Hoxie N, Vegeront J. Epidemiologic trends in infection, mortality and transplants related to hepatitis C in Wisconsin. WMJ 2006;105:34-9.  Back to cited text no. 4
    
5.Nancy Singh. NAT: Safe Blood, Safe India. Available from: http://www.expresshealthcare.in/200810/knowledge02.shtml.[Last cited on 2010, Jun 14].  Back to cited text no. 5
    
6.Irshad M, Peter S. Spectrum of viral hepatitis in thalassemic children receiving multiple blood transfusions. Indian J Gastroenterol 2002;21:183-4.  Back to cited text no. 6
[PUBMED]    
7.Mollah AH, Nahar N, Siddique MA, Anwar KS, Hassan T, Azam MG. Common Transfusion-transmitted Infectious Agents among Thalassaemic Children in Bangladesh. J Health Popul Nutr 2003;21:67-71.  Back to cited text no. 7
[PUBMED]    
8.Acharya SK. Hepatology in India. Sailing without a mast. Trop Gastroenterol 1999;20:145.  Back to cited text no. 8
[PUBMED]    
9.Sentinel Surveillance report. New Delhi: National AIDS control Organisation. 2001.  Back to cited text no. 9
    
10.Kleiman SH, Kuhns MC, Todd DS, Glyn SA, McNamara A, DiMarco A, et al. Frequency of HBV DNA in US blood donors testing positive for the presence of anti-HBc: Implications for transfusion and donor screening. Transfusion 2003;43:696-704.  Back to cited text no. 10
    
11.Wienberger KM, Bauer T, Bohm S, Jilg W. High genetic variability of the group-specific a-determinant of hepatitis B virus surface antigen (HbSAg) and the corresponding fragment of the viral polymerase in chronic virus carriers lacking detectable HbSAg in serum. J Gen Virol 2000;81:1165-74.  Back to cited text no. 11
    
12.Chattopadhyay S, Rao S, das BC, Sing NP, Kar P. Pervalence of transfusion transmitted virus infection in patients on maintenance hemodialysis from New Delhi, India. Hemodial Int 2005;9:362-66.  Back to cited text no. 12
    
13.Bhattacharya P, Chandra PK, Datta S, Banerjee A, Chakraborty S, Rajendran K, et al. Significant increase in HBV, HCV, HIV and syphilis infections among blood donors in West Bengal, Eastern India 2004-2005: Exploratory screening reveals high frequency of occult HBV infection. World J Gastroenterol 2007;13:3730-33.  Back to cited text no. 13
[PUBMED]  [FULLTEXT]  
14.Rao P, Annapurna K. HIV status of blood donors and patients admitted in KEM Hospital Pune. Indian J Hemat Blood Transf 1994;12:174-6.  Back to cited text no. 14
    
15.Rose D, Sudarsanam A, Padankatti T, Babu PG, John TJ. Increasing prevalence of HIV antibody among blood donors monitored over 9 years in one blood bank. Indian J Med Res 1998;108:42-4.  Back to cited text no. 15
    
16.Mathai J, Sulochana PV, Satyabhama S, Nair PK, Sivakumar S. Profile of transfusion transmissible infections and associated risk factors among blood donors of Kerala. Indian J Pathol Microbiol 2002;45:319-22.  Back to cited text no. 16
[PUBMED]  Medknow Journal  
17.Shrikrishna A, Sitalakshmi S, Prema Damodar S. How safe are our safe donors? Indian J Pathol Microbiol 1999;42:411-6.  Back to cited text no. 17
    
18.Nanu A Sharma SP, Chatterjee K, Jyoti P. Markers for transfusion-transmissible infections in north Indian voluntary and replacement blood donors: Prevalence and trends 1989-1996.Vox Sang1997;73:70-3.  Back to cited text no. 18
    
19.Garg S, Mathur DR, Garg DK. Comparison of seropositivity of HIV, HBV, HCV and syphilis in replacement and voluntary blood donors in western India. Indian J Pathol Microbiol 2001;44:409-12.  Back to cited text no. 19
[PUBMED]  Medknow Journal  
20.Sonwane BR, Birare SD, Kulkarni PV. Prevalence of seroreactivity among blood donors in rural population. Indian J Med Sci 2003;57:405-7.  Back to cited text no. 20
[PUBMED]  Medknow Journal  
21.Sawke N, Sawke GK, Chawla S. Seroprevalence of Common Transfusion - Transmitted infections among Blood Donors. People's Journal of Scientific Research. 2010;3(1):5-8.  Back to cited text no. 21
    
22.Gupta N, Kumar V, Kaur A. Seroprevalence of HIV, HBV, HCV and syphilis in voluntary blood donors. Indian J Med Sci 2004;58:255-7.  Back to cited text no. 22
[PUBMED]  Medknow Journal  
23.Busch MP, Glynn SA, Stramer SL, Strong DM, Caglioti S, Wright DJ, et al. A new strategy for estimating risks of transfusion-transmitted viral infections based on rates of detection of recently infected donors. Transfusion 2005;45:254-64.  Back to cited text no. 23
[PUBMED]  [FULLTEXT]  
24.National AIDS control Organization. Available from: URL http://www.nacoonline.org.[Last cited on 2010, Jun 14].  Back to cited text no. 24
    
25.Ramanamma MV, Rfamani TV. A Preliminary report on the seroprevalence of HIV-2 in Vishakapatnam. Indian J Med Microbiol 1994;12:212-5.  Back to cited text no. 25
    
26.Tallore SS, Shahapurkar A, Krishan BV. Prevalence of HIV infection among blood donors in North Karnataka. Indian J Med Microbiol 1997;15:123-5.  Back to cited text no. 26
    
27.Panda M, Kar K. HIV, hepatitis B and C infection status of the blood donors in a blood bank of a tertiary health care centre of Orissa. Indian J Public Health 2008;52(1):43-44  Back to cited text no. 27
    
28.Arora D, Arora B, Khetarpal A. Seroprevalence of HIV, HBV, HCV and syphilis in blood donors in Southern Haryana. IJPM 2010;53:308-9.  Back to cited text no. 28
    
29.Asif N, Khokhar N, Ilahi F. Seroprevalence of HBV, HCV and HIV infection among voluntary non remunerated and replacement donors in Northern Pakistan. Pak J Med Sci 2004;20:24-8.  Back to cited text no. 29
    
30.El-Hazmi MM. Prevalence of HBV, HCV, HIV-1, 2 and HTLV-I/II infections among blood donors in a teaching hospital in the Central region of Saudi Arabia. Saudi Med J 2004;25:26-33.  Back to cited text no. 30
[PUBMED]    
31.Ahmed MU, Begum HA, Hossain T, Chakraborty P. Incidence of Common Transfusion Transmitted Diseases Among Blood Donors; Journal of Armed Forces Medical college, Bangladesh. 2009; 5 (1):4-6.  Back to cited text no. 31
    
32.Shrestha AC, Ghimire P, Tiwari BR, Rajkarnikar M. Transfusion-transmissible infections among blood donors in Kathmandu, Nepal. J Infect Dev Ctries 2009;3:794-7.  Back to cited text no. 32
[PUBMED]  [FULLTEXT]  
33.Abdul Mujeeb S, Aamir K, Mehmood K. Seroprevalence of HBV, HCV and HIV infections among college going first time voluntary blood donors. J Pak Med Assoc 2000;50:269-70.  Back to cited text no. 33
[PUBMED]    
34.Jackson BR, Busch MP, Stramer SL, AuBuchon JP. The cost-effectiveness of NAT for HIV, HCV, and HBV in whole-blood donations. Transfusion 2003;43:721-9.  Back to cited text no. 34
[PUBMED]  [FULLTEXT]  
35.Gibbs WN, Corcoran P. Blood Safety in Developing Countries. Vox Sanguinis 2009;67:4377-81.  Back to cited text no. 35
    

Top
Correspondence Address:
B K Das
P-34, K B Roy Garden, Garia Station Road, Kolkata-700 084, West Bengal
India
Login to access the Email id


DOI: 10.4103/1755-6783.85758

Get Permissions




 
 
    Tables

  [Table 1], [Table 2]

This article has been cited by
1 Sero-epidemiology of Hepatitis B surface antigenaemia among adult Nigerians with clinical features of liver diseases attending a primary-care clinic in a resource-constrained setting of eastern Nigeria
Iloh, G.U.P. and Ikwudinma, A.O.
North American Journal of Medical Sciences. 2013; 5(4): 293-300
[Pubmed]
2 result 1 Document Seroprevalenceof HBs ag and HCV in healthy blood donors at a tertiary care hospital in India
Bhardwaj, K., Prasad, K.M., Bhardwaj, R., Bhardwaj, B.L.
Research Journal of Pharmaceutical, Biological and Chemical Sciences. 2013;
[Pubmed]
3 Viral Hepatitis in India
Abraham, P.
Clinics in Laboratory Medicine. 2012; 32(2): 159-174
[Pubmed]



 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *


    Abstract
   Introduction
    Materials and Me...
   Results
   Discussion
   Conclusion
    References
    Article Tables

 Article Access Statistics
    Viewed2310    
    Printed115    
    Emailed0    
    PDF Downloaded4    
    Comments [Add]    
    Cited by others 3    

Recommend this journal