Infectious Diseases & Urbanization in Developing Countries

Opeyemi S. OdewalePhD Student

Walden UniversityPUBH

Instructor: Dr. Rubin HowardSpring 2011

Overview

• Status of global waterborne infectious disease

• Waterborne pathogens

• Study focus: Hepatitis E Virus (HEV)

• Study focus: Developing countries ( India, Mexico & Nigeria)

• HEV health impact

• Need for concerns

• Prophylaxis & Vaccine

• Global Integration

• Reference (s)

Status of global waterborne infectious disease

Per year more than 3.4 million people die as a result of water related diseases, making it the leading cause of disease and death around the world ( WHO, 2005)

Image by Berto Garcia

 Image by Humanitarian and Development Partnership

 Eliminating disease and death due to unclean water and poor sanitation would reap billions of dollars in health and productivity gains; estimation indicates that for every dollar spent, there would be an economic return of between $3 and $34 ( WHO, 2005)

Waterborne pathogensStudy focus: Hepatitis E Virus (HEV)

Images CDC

Image World Hunger: Georgia State University

Hepatitis E Virus (enteric transmitted non-A, non-B hepatitis) StatusMicrobiology

• 27-34 nm, non-enveloped virions

• Single-stranded RNA genome: approximately 7.2 Kb,

• positive polarity, with 5’-cap

• Genus Hepevirus

• Family Hepeviridae Genotypes

• – Gt 1, 2: Only human infection

• – Gt 3, 4: Both humans and animalsClinical Presentation

• Acute hepatitis

• Sporadic hepatitis Transmitted person-to-person fecal-oral route

CDC, 2010

Hepatitis E Status

Genotype (Gt) geographical distribution :•Gt 1 and 2: epidemic strains causing human infection •Gt 3 and 4: zoonotic strains isolated from humans and a variety of animals

Pelosi & Clarke, 2008

Hepatitis E Status - Outbreak

Developing countries associated with HEV

• Study Focus:– India ( Asia)– Nigeria (Africa)– Mexico (North America)

Statistics of HEV -India

•Population growth rate is 1.41% ranking 93rd in the world •29.5% population in urban setting • 1955-1956 30 000 cases were reported in New Delhi•1997- 52 000 cases were reported in Kashmir

WHO, 2010

Statistics of Hepatitis E -Mexico

•Population growth rate is 1.1% ranking 106th in the world •77.2 % of population live in urban setting •1986 Genotype 2 outbreak•1988- 1989 4000 cases

Statistics of HEV -Nigeria

•Population growth rate is 1.94% ranking 59th in the world •48.4 of population in urban setting•1986 Genotype 2 sporadic infection outbreak in Port Harcourt

Health Impact – General Population

• Affects predominantly young adults

• Leading cause of acute viral hepatitis in South Asia, Africa, Middle East

• Mortality in general population 1-4%

• Causes substantial morbidity and mortality in older men

WHO, 2010

Health impact of HEV- Pregnancy

• Mortality in pregnant women ~20%

• Hepatitis and mortality in pregnant women during epidemics (10-20%) in 3rd trimester

• Causes intrauterine infection, prenatal morbidity and mortality

• Maternal death can occur due to encephalopathy, haemorrhagic diathesis or renal failure

• Cope, 2010 

Health Impact -Global transportation

Image Craig Mackintosh

Need for concern•Relatively new virus •Under diagnosed•Misdiagnosed •Globalization•Poor prognosis associated with pre-existing liver disease

Prophylaxis & Vaccine

Recombinant HEV vaccine has shownefficacy tailored to women. It boostersresponse following 3 doses, which indicates development in immunological memory

Wai Kuo Shih (2010)

Global Integration

Organization(s)

CDC

United Nation

UK- Health

Protection Agency

WHO

Reference• Alirol, E. Getaz, L. Stoll, B Chappuis, F.  Loutan, L (2011). Urbanisation and infectious diseases in a globalised world. The Lancet

Infectious Diseases, Volume 11, Issue 2, Pages 131 – 141

• CDC, (2010). Waterborne definition. www.cdc.gov/ncphi/disss/nndss/casedef/waterbornecurrent ( Retrieved 22-04-2011)

• Virginia Bioinformatics Institute(2011). Hepatitis E Virus. http://ci.vbi.vt.edu/pathinfo/pathogens/HEV.html (Retrieved 22-04-2011) 

• Aggarwal, R. Nanda, C.S. Wiersma, S. (2010). Global Prevalence of Hepatitis E Virus Infection and Suceptibility: A Systematic

Review. Department of Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India and World

Health Organization, Geneva, Switzerland  

• Cope, A. (2010). What Happened to Hepatitis E? Sheffield Teaching Hospitals

• Dalton, H.R. Bendall,R, Ijaz, S. BanKs, M (2008). Hepatitis E: an emerging infection in developed countries. The Lancet Infectious

Diseases, Volume 8, Issue 11, Pages 698 – 709 

• Wai Kuo Shih, J. (2010). Efficacy, Immunogenicity and Safety of a Recombinant Hepatitis E Vaccine. National Institute of

Diagnostics and Vaccine Development infectious diseases, Xiamen University, Seoul, Korea

• Myint, K. S.A. ( 2008). Hepatitis E : a neglect threat. Department of Virology, Armed Forces Research Institute of Medical Sciences,

Trans R Soc Trop Med Hyg 102:211-2

• Pelosi, E. Clarke, I., (2008). Hepatitis E: a complex and global disease. Emerging Health Threats Journal

• World Health Organizations (2005 & 2011). WHO: Waterborne Disease is World's Leading Killer. http://www.voanews.com. Voice of

America (Retrieved 28-04-2011)