Hepatitis Community Medicine HBV Public health sig HBV is 100 times more infectious than HIV. >350 million chronically infected worldwide. >1 million people die annually of HBV- related chronic liver disease. Established cause of chronic hepatitis & cirrhosis. Human carcinogen (cause of up to 80% of hepatocellular carcinomas). Highest incidence in Africa & Asia (occur in infancy & childhood). G/D High (>8%): 45% of global Intermediate (2%- 7%): 43% of Low (<2%): 12% of global population global Population: population: Prevalence Causative agent Lifetime risk of infection >60% Early childhood infections common HBc Ag Hbs Ag HBe Ag Lifetime risk of infection 20% - 60% Infections occur in all age group HBV, DNA virus, has 3 antigens Core antigen not detected in the blood. Outer lipoprotein coat. 4 subtypes & vary geographically. Appears at onset of disease. Lifetime risk of Infection <20% Most infections occur in adult risk groups. Associated with HBV replication & high infectivity. Resistance Survive outside the body at least 7days. Cases: clinical & subclinical Carriers (HBs Ag +ve): Reservoir 1. Incubatory, convalescent & healthy. 2. 6-10% of infected adults & 90% of infected infants become chronic carriers. Exit Blood & serum (highest concentration of virus). All tissue fluids: vaginal discharge, semen, saliva, tears, urine, feces & breast milk. Period of HBs Ag positives are potentially infectious. communicability From late I.P throughout convalescent stage for years and may persist for life. Portal of entry Percutaneous & Permucosal. Percutaneous (Parenteral) Through all types of injection (IV, & SC), infected needles in injecting drug abusers, blood transfusion, needle sticks, haemodialysis, acupuncture, or any injury from sharp instrument soiled by infected blood Mode of Invasive medical or dental procedures transmission Sharing razors or toothbrushes. Sexual transmission: Heterosexual or homosexual. Peri anal transmission Most infections occur intra- partum due to leak of maternal blood to baby circulation. Transmission through placenta or breast milk is rare. Risk of transmission affected by HBe Ag status of mother: If mother +ve for HBsAg & HbeAg: 70%- 90% of infants infected ; (90% become chronically infected). If +ve for HBsAg only: 5%- 20% of infants infected ; (90% become chronically infected) IP 6 weeks 6 months
Susceptibility CP Complication Diagnosis General Prevention Specific prevention Age Immunity High risk groups Disease is asymptomatic (an- icteric)& mild in children & infants. Infection gives lifelong immunity in those who do not become chronic carriers. Vaccination gives high protective value (5-7 years). HCWs exposed to blood, blood product or accidental needle sticks. IV drug abusers & Infants of infected mothers. Haemodialysis patients & patient subjected to repeated blood or transfusion. Homosexual, bisexual & Heterosexual partners of infected persons. 50% of infections asymptomatic. 3 stages as hepatitis A with 3 differences: 1. Fever mild or absent & icteric stage more often occurs. 2. Fulminating fatal case of acute hepatic necrosis. 3. Chronicity. Acute atrophy, recurrent hepatitis, cirrhosis & HCC 1. Acute hepatitis B: q Suspected case: C/P described in HAV. q Confirmed case: +ve IgM anti- HBc + HBV DNA in serum. 2. Serology: determines whether acute or chronic General prevention of parenteral transmission Drug use Stop illegal drugs Avoid sharing drug injection equipment with others. Medical procedure Blood banks strategies: Good selection of blood donors : should be free from HbsAg). Exclusion of & those with past history of hepatitis & addicts. Dentists & other healthcare professionals: 1. Standard hygienic precautions. Acupuncture Sanitary precaution during tattooing Prevention of Perinatal transmission: combined seroprophylaxis & vaccination to infants. Safer sex practices: use of condoms (does not provide 100% protection). Health Education : about source of infection, mode of transmission & preventive measures. Vaccination Nature 2 types of inactivated vaccines: 1. Plasma derived: prepared from plasma of HBsAg positive carriers. 2. Yeast recombinant. Efficacy 95% for 5 7 years, also its prevent complications Dose 1 ml l.m injection in the deltoid region at 0, 1 & 6 months respectively. Indications Compulsory in Egypt: 3 doses l.m each 0.5 ml in the 2 nd, 4 th, 6 th months baby. High risk groups: contacts, international travelers to endemic areas. HIHT Complications Allergic reactions to vaccine components as yeast, latex, aluminum, formaldehyde & thimerosal. Post- vaccination testing: 1-2 months after 3rd vaccine dose. A protective antibody response is 10 miu/ml. Non- responders should be vaccinated at 0, 1 & 6 months.
Specific prevention Control Treatment Seroprophylaxis: HSI contains anti HBs (0.06 ml/kg) as soon as possible after exposure. Indications: Ø PEP alone or combined with vaccination. Ø Risk of infection from needle stick contaminated with HB+ve blood ranges from 6% - 30% Reduced by 80% with 2 HB1G doses, 1 immediately after exposure & other 1 month later. Combination of vaccine and immunoglobulins Exposure Management Perinatal Percutaneous or Per mucosal Sexual contact Household contact one dose of HBIG + vaccine. HBIG ± vaccine (depending on vaccination status). acute exposure: HBIG + vaccine chronic exposure: Vaccine. acute exposure: HBIG + vaccine. chronic exposure: Vaccine. Cases Contacts Ø Early case finding. Enlistment. Ø Notification: to LHO. Surveillance: Ø Segregation with standard precautions to for early case & carrier finding by serology for prevent exposure to blood & body fluids. HBs Ag. Ø Disinfection: Combination of vaccination & Igs (at the Concurrent: of blood previous table). contaminated articles & fomites. Terminal: using chlorine solution. Epidemic measures 1. Strict precautions in blood banks. 3. Health education of public. 2. Survey studies for additional cases. 4. Mass vaccination. For acute HB: no specific treatment. For chronic HB: antiviral drugs & alpha interferon to stop virus replication.
Public health significance Causative agent Reservoir Exit Period of communicability MOT IP High risk groups Clinical picture Diagnosis Prevention HCV Public health significance: q Worldwide ( 3% of population live with HCV), 4 times higher than people live with HIV. q Clinical risk to medical profession. q Financial risk to health organizations & society due high treatment costs. q Established cause of chronic hepatitis, cirrhosis & HCC q High prevalence in Egypt (10-15%) & High annual mortality (45.8 0/00). q High prevalence in Lower Egypt, lower in Upper Egypt & low in cities. q Transmission through parenteral anti- schistosomal therapy may explain high prevalence. q After cessation of PAT (mid- 1980s), large reservoir of chronic infections provided continued transmission through other routes of exposure HCV (RNA), 11 genotypes, subtypes (a. b, c etc) & 100 distinct strains. In Egypt (genotype 4a). Mutates rapidly to escape host immune responses. Survive outside body for 16 hours up to 4 days. Inactivated by lipid solvents or detergents In - apparent disease in 75% of infection (Cases less severe than HBV& Carriers are usually temporary). blood & blood products during period of HCV positivity(+ve HCV RNA & anti- HCV). As hepatitis B Mainly by blood & blood products, infected needles & syringes. Low sexual & perinatal transmission. 5 to 10 weeks HCWs (risk from needle stick is 3%). I V drug abusers & Infants of HC +ve mothers (6% vertical transmission rate). Haemodialysis patients & patient subjected to repeated blood or transfusion. Homosexual, bisexual & Heterosexual partners of infected persons. Acute infection Chronic infection Usually asymptomatic (occasionally malaise/ jaundice). 20 % recovery & 80% remain chronically infected. Suspected case Compatible with clinical description No symptoms (majority). Progressive liver damage over next 20 years: Cirrhosis (16%), HCC (1-2% of those with cirrhosis). Standard case definition Primary and secondary prevention is same as HBV Confirmed case Laboratory confirmed (+ve anti- HCV).
Control PEP Treatment S/E IFN Tertiary prevention Case Contacts Epidemic measure 1. Early case finding. 2. Notification. 3. Segregation: As B 4. Disinfection: As B 5. Treatment: 1. Enlistment. 2. Early case & carrier finding by serology for HCV. 3. Investigation of contacts & source of infection. 4. PEP Same as HBV but no vaccine Test source for anti- HCV. Test HCW if source anti - HCV +ve. Anti- HCV & ALT at baseline & 4-6 months later. For earlier diagnosis, HCV RNA at 4-6 weeks. Medical evaluation & management. Interferon + Ribavirin: (teratogenic & cause haemolytic anaemia). Autoimmune: (hypothyroidism & DM). Alopecia. Neuropsychiatric: (depression, insomnia & irritability). Haematologic: (leucopoenia & thrombocytopenia). Constitutional: (fever, rigors, arthralgia, myalgia & fatigue). Ocular. Weight loss. Management of Complications : cirrhosis, liver cell failure, bleeding oesophogeal varices, complications encephalopathy or HCC. Patients with decompensated liver disease may be considered but Recurrence of HCV infection > 90% in liver grafts. Liver Level of viraemia increases dramatically with post- transplant Transplantation immunosuppression Poor survival rates. High morbidity & mortality among donors from liver affection.