Viral hepatitis


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Viral hepatitis

  2. 2. Viral hepatitis can be defined as the infection of liver caused by different viral agents.<br />AEITOLOGICAL AGENTS<br />HAV<br />HBV<br />HCV<br />HDV<br />HEV<br />HGV<br />They can be other viruses which can be impliciated in hepatitis such as Cytomegalo virus, Epstein-Barr virus ,rubella virus.<br />VIRAL HEPATITIS<br />
  3. 3. Hepatitis A is caused by hepatitis A virus(HAV).<br />The disease manifest by non-specific symptoms <br />Fever<br />Chills<br />Headache<br />Fatigue<br />Generalized weakness<br />Followed by <br />Anorexia<br />Nausea<br />Vomitting<br />Dark urine<br />jaundice<br />HEPATITIS A<br />
  4. 4. The disease is completely recovered in most of the cases and has mortality rate of 0.1% but patients may be incapaciated for weeks.<br />
  5. 5. AGENT FACTORS<br />Agent-it is an entero-virus(type 72) of picornaviridae family.<br /> it multiplies in hepatocytes.<br /> only one serotype is known.<br />RESISTANCE- The virus is fairly resistant to heat and chemicals.<br /> It can survive for more than 10 weeks in well water, withstand heating of 60deg for more than 1 hour, not affected by chlorination that is employed, formaline is effective .UV rays, boiling for 5 minutes and autoclaving is effective. <br />EPIDEMIOLOGICAL DETERMINANTS<br />
  6. 6. RESERVOIR OF INFECTION<br />Humans are only reservoir.<br />Cases ranges from asymptomatic to severe form.<br />Asymptomatic cases are mainly present in childrens , these cases are responsible for maintaining chain of transmission.<br />No evidence of chronic carrier state.<br />PERIOD OF INFECTIVITY<br />2 week before to one week after onset of jaundice<br />Infectivity falls with onset of jaundice.<br />
  7. 7. INFECTIVE MATERIAL<br />Man’s faecesmainly.<br />Blood, serum and other fluid are infective only during brief period of viraemia.<br />VIRUS EXCRETION<br />It is excreted 2 weeks before onset on jaundice and 1 week thereafter.<br />May also be excreted in urine. <br />
  8. 8. AGE-<br />More frequent among children.<br />But all age groups are susceptible. In young children infection is mild or sub-clinical but severity increases with age.<br />SEX- <br />Both sex are at equal risk.<br />IMMUNITY<br />Immunity after an attack generally lasts for life.<br />Second attack have been reported in 5% of cases.<br />In endemic areas immunity is acquired through sub-clinical infection.<br />Early in the infection IgM antibody appears and lasts for 90 days but later on IgG appears and lasts for years. <br />HOST FACTORS<br />
  9. 9. Cases are seen throughout the year but mostly associated during period of heavy rainfall.<br />Poor sanitation and over-crowding favors spread of infection. <br />ENVIRONMENTAL FACTORS<br />
  10. 10. Faecal-oral route –this the major route of tranmision.<br /> directly- contaminated hands or objects as eating utensils. direct transmission occur under condition of poor sanitation or over-crowding.<br /> indirect- contaminated water, food or milk.<br />Parenteral route – very rare. It is transmitted by blood, blood products or contaminated needles during stage of viraemia.<br />Sexual transmission- seen in homosexual. <br />MODE OF TRANSMISSION<br />
  11. 11. 15-45 Days (usually 25 to 30 days)<br />The length of incubation period depends upon the dose of virus ingested.<br />INCUBATION PERIOD<br />
  12. 12. Demonstration of HAV particles or specific viral antigen in the faeces.<br />Demonstration of a rise in anti-HAV titre.<br />Detection of IgM antibody to HAV in the patient’s serum or IgG antibody to HAV.<br />DIAGNOSIS<br />
  13. 13. Control of reservoir<br />Control of reservoir is difficult<br />Faecal shedding is highest during incubation period and early phase of illness.<br />Occurrence of large number of sub-clinical cases.<br />Absence of specific treatment.<br />Low socio-economic profile of popullation involved.<br /> so notification, complete bed rest and disinfection of faeces and fomites should be done. <br />Prevention and containment<br />
  14. 14. Can be obtained by simple measures as<br />Handwashing<br />Sanitary disposal of excreta will prevent contamination of water, milk ,food.<br />Purification of community water by flocculation, filtration or chlorination.<br />During epidemics people should be advised to boil water before using for drinking purposes. Other control measure can be proper autoclaving of syringes, needles and other instruments. <br />2.Control of transmission<br />
  15. 15. Human immunoglobulin<br />Use of human immunoglobulin prepared from pooled plasma of healthy donor for induction of passive immunity. It is recommended for<br />Susceptible person travelling to highly endemic area.<br />Close personal contact.<br />For control of institutional out-breaks.<br />Dose-3.2-8.0 mg/kg body weight <br />3.Control of susceptible population<br />
  16. 16. Several inactivated and live attenuated vaccine have been developed.<br />Vaccine must commonly used is combination vaccine containing inactivated hepatitis A and recombinant hepatitis B .the combination vaccine is used in 3 dose series ie, 0,1 and 6 month series. <br />4.vaccines<br />