Epidemiology of viral hepatitis infection .pptx
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Globally, there’s a huge number of undiagnosed and untreated people living with hepatitis. Deaths from viral hepatitis-related causes are increasing.
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Epidemiology of viral hepatitis infection .pptx
- 1. Epidemiology of intestinal infections Viral hepatitis Dr L Aruna Assistant professor Community medicine Dept
- 2. Intestinal infections • Poliomyelitis • Viral hepatitis • Acute diarrhoeal diseases • Cholera • Typhoid fever • Food poisoning • Amoebiasis • Ascariasis • Hook worm infections • Dracunculiasis 2
- 3. • Which of the Hepatitis B Virus serological marker indicates the first evidence of Hepatitis B infection? • (a) Anti-HBs (b) Anti-HBc (c) HBeAg (d) HBsAg • A mother is HBsAg positive at 32 weeks of pregnancy. What should be given to the newborn to prevent neonatal infection? • (a) Hepatitis B vaccine + Immunoglobulin • (b) Immunoglobulin only • (c) Hepatitis B vaccine only • (d) Immunoglobulin followed by vaccine 1 month later 3
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- 5. World Hepatitis Day 2024 It's time for action • 304 million people are living with chronic hepatitis B and C in 2022 • • Only 45% of babies received the hepatitis B vaccine within 24 hours of birth in 2022 • • 1.3 million people died of chronic hepatitis B and C in 2022 • 5
- 6. Introduction • A liver performs over 500 vital functions every single day to keep us alive, that’s why testing, treating and preventing viral hepatitis is so important. • Globally, there’s a huge number of undiagnosed and untreated people living with hepatitis. • Deaths from viral hepatitis-related causes are increasing. 6
- 7. • 3 500 people die from hepatitis B and C infections every day. That’s around one hepatitis death every 30 seconds. • Over 6 000 people are newly infected with viral hepatitis each day. • So many hepatitis infections – and deaths – can be prevented. 7
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- 12. Viral Hepatitis Clinically similar , but aetiologically & epidemiologically distinct diseases. 5 viruses, transmission through 1. Contaminated food & water: - Hepatitis A & E 2. Through blood & body fluids: - Hepatitis B,C &D 12
- 13. Hepatitis A Infectious hepatitis / epidemic jaundice Global incidence of 1.4 million cases every year Case fatality rate is < 0.1% due to Acute liver failure 1. Areas with high levels of infection: developing countries 2. Areas with intermediate levels of infection: countries with transitional economies 3. Areas with low levels of infection: developed countries 13
- 14. • A major outbreak of hepatitis A (HAV), associated with consumption of raw clams, occurred in Shanghai, China in 1988. Over 300000 cases were reported, of which 47 (0.015%) were fatal. 14
- 15. • India is hyperendemic for HAV infection • Sporadic & epidemics of cases in various cities, residential areas , campuses etc…. • Occurrence of cases: slow / explosive. 15
- 16. Epidemiological determinants • Agent: Enterovirus , picornaviridae family • Resistance: low Ph, heat & chemicals • Formalin acts as an effective disinfectant • inactivated by UV rays, autoclave • Human cases are the only reservoirs • Period of infectivity- 2wks before to 1wk after the onset of jaundice • Infective material : faeces, blood ,serum & other fluids 16
- 17. Host: age, immunity • Environmental factors: • Through out year • Disease trends associated with heavy rainfall • Poor sanitary conditions & overcrowding • Modes of transmission: • Faecal oral route • Parenteral route • Sexual transmission 17
- 18. Incubation period: 10 to 50 days Clinical spectrum: GI symptoms- nausea ,vomiting, anorexia, mild fever & jaundice. Anicteric hepatitis is more common Complete recovery in 98% cases but relapse of symptoms in 3-20%. Diagnosis: 1) LFT : ALT & bilirubin 2) Pathological, epidemiological & clinical findings 3) Lab: HAV particles, viral Ag 4) ELISA: IgM specific anti-HAV antibodies 18
- 19. Prevention & containment 1. Control of reservoir 2. Control of transmission 3. Control of susceptible population Control of reservoir: Strict isolation of cases and bed rest Disinfection with 0.5% sodium hypochlorite 19
- 20. Control of transmission 1. promoting personal & community hygiene: Hand hygiene, prevent contamination of water, food& milk. 2. Safe water supply : 1mg/L residual chlorine for 30 minutes at < 8.5 pH Epidemics: consumption of boiled water ● Complete inactivation of HAV in food can be done by heating at 85°C for at least one minute 20
- 21. Control of susceptible population High risk groups: • Travellers to intermediate & high endemicity areas • People with life long treatment with blood products • Workers in contact with non-human primates • I V drug users • Patients with chronic liver disease Vaccines : • 1. formaldehyde inactivated vaccine: IM , 2 doses • 2. live attenuated vaccines: SC, single dose 21
- 22. Hepatitis B * Serum Hepatitis • Acute: self –limiting disease with 0.5 to 1% case fatality rate • Chronic: active viral replication & hepatocellular injury . • Age acts as a key role in in determining the risk of chronic infection. • Hep B virus can form dangerous alliance with delta virus ,produces virulent hepatitis – widespread threat to world. 22
- 23. Epidemiological factors • Agent: double shelled DNA virus- “DANE particle” • Three morphological forms- . Small spherical ,Tubules • Dane particle- INFECTIOUS • Reservoir of infection: man is the only reservoir. • Infective material : contaminated blood , other body fluids. • Resistance: able to survive up to 7 days on surfaces • Period of communicability : several months 23
- 24. Host factors: Disease outcome depends on the age of the individual , • The younger a person is when infected with the hepatitis B virus, the greater the chance of developing chronic infection. About 9 in 10 infants who become infected go on to develop life-long, chronic infection. The risk goes down as a child gets older. • High risk groups: surgeons, health care professionals , lab personnel • Recipients of blood transfusion, homosexuals , prostitutes, percutaneous drug users , infants of HBV mothers, recipients of organ transplants & immunocompromised individuals . • Serological screening and vaccination of high risk groups – highly recommended. 24
- 25. Hep B & HIV infection : HIV increases the risk of developing HBV – associated liver cirrhosis & hepatocellular carcinoma. Mortality rate increases in HIV positive people with co-infection of HBV , in spite off ARV therapy. Humoral & cellular responses : three Ags 1. Australia Ags - HBsAg 2. core Ags - HBcAg 3. ‘e ‘ Ags- HBeAg They stimulate the production of corresponding antibodies. 25
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- 27. Modes of transmission • Parenteral route: blood & blood products, contaminated needles, pricks of skin, handling of infected blood,surgical &dental procedures, immunization,traditional tattooing , ear& nose piercing, ritual circumcision,accupunture, shared razors,tooth brushes, etc. • Perinatal transmission : from HBV mothers to babies , risk of infection is more unless vaccinated at birth. • Sexual transmission: intimate or sexual contact, • Other routes: horizontal transmission • Incubation period: 30 to 180 days 27
- 28. Clinical picture 1) The clinical picture is complicated by carrier state or pre existing chronic liver disease. 2) In some people , it is inactive and it doe’s not progress to ch.liver disease, 3) In some , progressive liver fibrosis-------cirrhosis with end stage liver disease-----------hepatocellular carcinoma. 4) Host & viral factors especially coinfections with HIV, HCV & Hepatitis D virus & cofactors like alcohol use increase the developing HCC. 28
- 29. Diagnosis: RDTs, EIAs, CLIAs & ECLs 29
- 30. Markers of Hepatitis B infection (in order of appearance in serum): – 30 HBsAg : - Also known as ‘Australia antigen’ - First antigen to appear in serum – ‘first evidence of infection’ - ‘Epidemiological marker of Hepatitis B infection’ HBcAg: - Alone does not appear in serum – HBeAg : - Is a secretory form - ‘Indicates active viral replication’ - ‘Is a marker of infectivity for Hepatitis B’ - Persistence beyond 3 months: Increased likelihood of chronic Hepatitis B – Anti-HBc : - First antibody to appear in serum - IgM Anti-HBc indicates a diagnosis of acute Hepatitis B - IgG Anti-HBc persists indefinitely – Anti-HBe : - Signals ‘stoppage of active viral replication’ - Indicates ‘end of period of infectivity’ – Anti-HBs : - Last antibody to appear in serum - Signals ‘recovery, end of period of communicabilit
- 31. • Persistent carrier state in Hepatitis B: Presence of HBsAg for > 6 months • Carrier rate of HBsAg in Indian population: 5% (general population) – 10% (hospital staff) • Mother to child transmission (MTCT) of HBV: – In presence of HBeAg: 90% – In presence of HBsAg: 20% • Antibody in serum after successful, vaccination against HBV: Anti-HBs • Most sensitive marker of HBV viral replication and infectivity: HBV DNA 31
- 32. Prevention containment • Hepatitis B vaccine : plasma derived , monovalent or fixed combination, • Dose – adults 10to 20 mgs 0,1,6 months, • NIS: BIRTH DOSE , followed by 6,10,14 wks • Hepatitis B Immunoglobulins (HBIG): for immediate protection- 1.surgeons, nurses & lab personnel • 2.newborn infants of carrier mothers • 3.LIVER transplantation • 4. sexual contacts of acute Hepatitis B pts 32
- 33. Passive- active immunization: • This combined procedure • 1. for prophylaxis to persons accidental exposure to blood contain Hep B virus. • 2. for prevention of carrier rate in newborns of carrier mothers • Other measures: • all blood donors should be screened for HBV • ADEQUATE STERLIZATION OF ALL THE ISTRUMENTS • Carriers should not be share razors , tooth brushes, • Carriers should follow barrier method for contraception 33
- 34. Prevention and Control measures • Safe sexual practices , Use of Condoms • Safe hygiene practices (not sharing shaving blades) • Safe blood transfusion and injections • Health care personnel to practice proper “Universal safety precautions” and correct disinfection procedures • Biomedical waste management as per laid down guidelines 34
- 35. Hepatitis C - Epidemiology • “non A, non B hepatitis”. • HCV is one of the major cause of acute hepatitis and chronic liver disease, including cirrhosis and liver cancer . • No vaccine available to prevent HCV • Globally , 3-4 million new cases every year, • 110 million people with HCV, • @ 4Lacs deaths, • 23 lacs people were co-infected with HCV&HIV 35
- 36. Agent: RNA virus, genus Hepacivirus in the family Flaviviridae. Host : high risk people - recipients of blood transfusions, healthcare and laboratory personnel, homosexuals, prostitutes, percutaneous drug abuser, infants of HCV carrier mothers. Modes of transmission: sexual contact, contaminated with infectious blood & blood products , organ donation, needles, newborn of HCV carrier mother. Incubation period : 14 days to 180 days 36
- 37. Clinical features: 60-80% are asymptomatic & only 15-30% are symptomatic ( jaundice). Clinical picture is similar to other viral hepatitis Distinct feature of HCV infection is that about 80% of newly infected patients progress to develop chronic infection Cirrhosis develops in about 10% to 20% of persons with chronic infection & liver cancer develops in 1% to 5% of persons with chronic infection over a period of 20 to 30 years. Most patients suffering from liver cancer who do not have hepatitis B virus infection have evidence of HCV infection.. 37
- 38. Diagnosis • Enzyme Immunosorbant Assays (EIA) for the detection of HCV specific antibodies. EIAs can detect more than 95% of chronically infected patients but can detect only 50% to 70% of acute infections. • A Recombinant Immunoblot Assay (RIBA) identifies antibodies which react with individual HCV antigens is often used as a supplemental test for confirmation of a positive EIA result. • PCR can be utilized for confirmation , as well as for assessing the effectiveness of antiviral therapy. • A positive result indicates the presence of active infection and a potential for spread of the infection and or/the development of chronic liver disease 38
- 39. Prevention and Control of Hep C • There is no vaccine against HCV. • Screening and testing of blood and organ donors. • Virus inactivation of plasma derived products. • Implementation and maintenance of infection control practices in health care settings, including appropriate sterilization of medical and dental equipment. • Promotion of behaviour change among the general public and health care workers to reduce overuse of injections and to use safe injection practices; and risk reduction counselling for persons with high-risk drug and sexual practices 39
- 40. Hepatitis D is a defective single-stranded RNA virus, • It requires HBV to replicate. HDV infection can be acquired either as a co-infection with HBV or as a Superinfection of persons with chronic HBV infection. • Epidemiology: corresponds to prevalence of chronic HBV infection; • Agent : The hepatitis delta virus - RNA virus, • Host : Intravenous drug users , Promiscuous homosexual and heterosexual groups. ● People exposed to unscreened blood or blood products such haemophiliacs, persons with clotting factor disorders. 40
- 41. • Modes of Transmission : Transmission is similar to that of HBV • Incubation Period : The incubation is period similar to HBV infection 30 to 180 days • prevention of HDV superinfection depends primarily on education to reduce risk behaviours 41
- 42. Hepatitis E • Enterically transmitted non-A non-B (HNANB), • Epidemiology. Every year, ≈20 million HEV infections occur globally; ≈3.3 million cases are symptomatic hepatitis E, ≈70,000 deaths occur. • Mode of transmission: food –borne , blood transfusion, mother to baby • Incubation period of HEV infection : 2–9 wks • The spectrum of illness ranges from asymptomatic to severe disease resulting in fulminant hepatitis and death. • For most people, hepatitis E is a mild, self-limited disease. 42
- 43. • Signs and symptoms of acute hepatitis E include abdominal pain, anorexia, fever, jaundice, and lethargy, • Pregnant people with HEV-1 infection, especially those infected during the third trimester, might present with or progress to fulminant liver failure and death, and are at risk for spontaneous abortion and premature delivery. 43
- 44. good personal hygiene, high quality standards for public water supplies and proper disposal of sanitary waste are the mainstay of prevention and control of infective hepatitis Water should be preferably boiled during an outbreak. Sanitation should be kept at a very high level. Methods of proper disposal of human wastes and strict anti-fly measures should be reinforced. Particularly cooks and housewives must be persuaded to wash their hands with soap and water after defaecation and before handling or consuming food. 44
- 45. Hepatitis G – RNA virus • Incubation period ranges from 30-120 days. • Mode of transmission : sexual contact or vertical transmission from mother to child. It is often detected in patients who received multiple blood transfusion or in hemodialysis patients & IV drug users. • It produces a persistent infection in a high proportion of persons with or without acute hepatitis or hepatitis -related chronic liver disease . • no vaccine or treatment of HGV, • Prevention : avoiding high RISK behavior 45
- 46. 46 Thank you
Editor's Notes
- Geographical areas
- Slow: few months, explosive: common source – faecal contamination of drinking water
- SAFE water supply : destruction of virus
- fulminant liver disease , Hepatitis A vaccine is preferable compare to Ig(Human immunoglobulin)
- Acute: inflammation & hepatocellular necrosis. Chronic : persistent HBV infection with /out viral replication
- 50 times more when compare to general population, twice with that of other physicians. Age plays a role in whether hepatitis B will become chronic.
- Blood transfusion , dialysis, , children born to mothers who are HBeAg – positive become chronically infected
- It shows diversity in disease spectrum
- is a viral infection of the liver which was initially referred to as parenterally transmitted , until identification of the causative agent in 1989
- The clinical illness in persons with acute hepatitis C is similar to that observed in hepatitis of other viral etiologies and the diagnosis of hepatitis C can only be made with appropriate serologic testing.
- Research is in progress but due to high mutability of the HCV genome, possibility of development of vaccine in the foreseeable future seems remote. Hence in the absence of a vaccine, all precautions to prevent infection must be taken including
- it requires the helper function of hbv, it requires the helper function of
- single stranded RNA virus which belongs to the flavivirus family. however it has shown high sensitivity to interferon but most cases relapsed after completion of treatment, prevention relies on avoiding any possible contact with contaminated blood. Drug users should not share needles, syringes, or other equipment.