醫(yī)學(xué)微生物學(xué)課件(已改無(wú)錯(cuò)字)
2023-01-18 03:51:24 本頁(yè)面
【正文】 ns of chronic hepatitis B infection may be seen, albeit with a lower frequency . chronic persistent hepatitis, chronic active hepatitis, cirrhosis, and hepatocellular carcinoma 病理 ? HCV不直接殺傷細(xì)胞 ? 病理免疫和細(xì)胞凋亡是造成傷害原因 Transmission of HCV ? Percutaneous ?Intravenous drug abuse ?Transfusion, transplant ?Therapeutic (contaminated equipment, unsafe injection practices) ? Permucosal ?Perinatal ?Sexual Sources of Infection for Persons with Hepatitis C Sexual 15% Other* 5% Unknown 10% Injecting drug use 60% Transfusion 10% (before screening) *Nosoial。 Healthcare work。 Perinatal Source: Centers for Disease Control and Prevention Source: Sentinel Counties, CDC HCV Prevalence by Selected Groups, USA 0 10 20 30 40 50 60 70 80 90Hemophilia Injecting drug users Surgeons, PSWs Hemodialysis Average Percent AntiHCV Positive Gen population adults Military personnel STD clients Pregnant women Prevalence of HCV Infection by Age Gender, 19881994 USA 0123456611 1219 2029 3039 4049 5059 6069 70+Age in YearsPercent AntiHCV PositiveMales Females Source: CDC, NHANES III Total Perinatal Transmission of HCV ? Transmission only from women HCVRNA positive at delivery ? Average rate of infection 6% ? Higher (17%) if woman coinfected with HIV ? No association with ? Delivery method ? Breastfeeding ? Infected infants do well ? Severe hepatitis is rare Household Transmission of HCV ? Rare but not absent ? Could occur through percutaneous/mucosal exposures to blood ? Theoretically through sharing of contaminated personal articles (razors, toothbrushes) ? Contaminated equipment used for home therapies ? Injections* ? Folk remedies *Reported in . Serologic Pattern of Acute HCV Infection with Recovery Symptoms +/ Time after Exposure Titer antiHCV ALT Normal 0 1 2 3 4 5 6 1 2 3 4 Years Months HCV RNA Serologic Pattern of Chronic HCV Infection with Progression Infection Symptoms +/ Time after Exposure Titer antiHCV ALT Normal 0 1 2 3 4 5 6 1 2 3 4 Years Months HCV RNA Laboratory Diagnosis ? HCV antibody generally used to diagnose hepatitis C infection. Not useful in the acute phase as it takes at least 4 weeks after infection before antibody appears. ? HCVRNA various techniques are available . PCR and branched DNA. May be used to diagnose HCV infection in the acute phase. However, its main use is in monitoring the response to antiviral therapy. ? HCVantigen an EIA for HCV antigen is available. It is used in the same capacity as HCVRNA tests but is much easier to carry out. HCV Infection Testing Algorithm for Diagnosis of Asymptomatic Persons EIA for AntiHCV Negative (nonreactive) STOP Positive (repeat reactive) OR RIBA for AntiHCV RTPCR for HCV RNA Negative STOP Additional Laboratory Evaluation (. PCR, ALT) Negative Positive Indeterminate Medical Evaluation Positive Negative PCR, Normal ALT Positive PCR, Abnormal ALT Source: MMWR 1998。47 (No. RR 19) Routine HCV Testing Not Remended (Unless Risk Factor Identified) ? Healthcare, emergency medical, and public safety workers ? Pregnant women ? Household (nonsexual) contacts of HCVpositive persons ? Screening of blood, an, tissue donors ? Highrisk behavior modification ? Blood and body fluid precautions Prevention of Hepatitis C Estimated Incidence of Acute HCV Infection, 19601999 USA 0204060801001201401960 1965 1970 1975 1980 1985 1989 1995 1999YearNew Infections/100,000Decline in transfusion recipients Decline in injection drug users Source: Hepatology 2023。31:77782 Hepatology 1997。26:62S65S Posttransfusion Hepatitis C 0510152025301965 1970 1975 1980 1985 1990 1995 2023Year% of Recipients InfectedAll volunteer donors HBsAg Donor Screening for HIV Risk Factors AntiHIV ALT/AntiHBc AntiHCV Improved HCV Tests Adapted from HJ Alter and Tobler and Busch, Clin Chem 1997 Treatment ? Interferon may b
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