Hepatitis

Hepatitis

PKGhatak,MD                                                         

          

                                                 

Yellow Fever is now classified under acute viral hemorrhagic fever but it is viral hepatitis.  The methodology used in the investigation of yellow fever outbreaks opened the doors for all future studies in the epidemiology of viral hepatitis. 

In colonial America, outbreaks of Yellow Fever were frequent.  In 1904 USA took over the construction of the Panama Canal from the French and thousands of US workers went there to work. Over 5000 workers died of yellow fever and malaria during canal construction. Carlos Findlay of Cuba theorized that man to man of yellow fever did not occur and in 1881 he identified a mosquito - Ades egypti, which was responsible for the spread of the disease. Walter Reed confirmed Findlay’s observation and Reed’s research proved that the yellow fever virus infected jungle monkeys and the monkey acted as a natural reservoir of the virus. When men entered their domain, the mosquitoes attacked men and infected mosquitoes transmitted the yellow fever virus to men.  For his work, Carlos Findlay was nominated seven times for the Nobel Prize in Medicine; he, however, did not get the prize. Max Theiler of South Africa won the Nobel Prize in 1951 for discovering an effective vaccine.   

In present days medical journals, you will find discussions on viral hepatitis; they are mostly on hepatitis C (HCV) and occasionally also other forms of viral hepatitis. The cable news and newspapers will whip up your anxiety, from time to time, with reports of outbreaks of a few cases of Infectious Hepatitis, also called HAV or hepatitis A virus infection. Compared with Yellow fever, Infectious Hepatitis is a relatively mild disease and fatality is rare.

The story is quite different in South Asia where Hepatitis A infection is endemic. The poorer the country the more prevalent the disease is and the government statistics are either non-existent or simply unreliable.

Hepatitis A.
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It is transmitted from man to man by the fecal-oral route and is highly contagious.

When a person is infected with the virus, initially he has no symptoms but the virus keeps on multiplying in his body. He sheds the virus in his stool. Contaminated water and food are the primary mode of spread of hepatitis A, sexual contact and sharing needles among IV drug users also spread the disease. Even when patients recover from the infection, they would continue to shed the virus for another 2-3 weeks. In South Asian countries the monsoon rain often inundates the cultivated fields; overflow sewer water also ends up in fields and contaminates the produce. People eating raw vegetables, shellfish, or fresh fruits are infected. The rich and affluent middle class often employ 2 -3 domestic help as cooks, kitchen help, etc., they are poor and live in appalling unsanitary conditions. They have no knowledge of fecal-oral transmission of hepatitis, and hardly ever wash their hands with soap and water after visiting toilets. This mode of spread of a disease is called the fecal-oral route of transmission. You may not know that people working in restaurants in many South Asian countries are not required to carry food-handler certificates. Consequently, you are at risk when you eat out. If you have neglected HAV vaccination, check your vaccine status before you leave home.

Infected people when recovering from HAV infection carry a lifelong immunity; others can protect themselves by taking the HAV vaccine.

Hepatitis B.
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People infected with this virus carry the virus in all of their body fluids including saliva.

Transfusion of contaminated blood or blood products, sharing infected needles and sexual intercourse are the usual modes of transmission of HBV (hepatitis B virus). Late in pregnancy mother may pass the virus to the unborn child and also may infect during childbirth. Breastfeeding does not add any risk.  Since mandatory screening for hepatitis was instituted in donated blood and blood products the HBV by transfusion is nearly eliminated. All newborns are vaccinated for HBV and adults are going to be covered for HBV vaccination by the new health care bill. HBV is still a problem for HIV infected people. The new cases of HBV infection are decreasing rapidly; hopefully, it will be eliminated in the near future.

Hepatitis C.
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It is a blood-borne infection like HVB; however, the virus is less virulent.
The mode of transmission is usually by sharing IV needles and transfusion of contaminated blood and blood products and by sexual contact. Transmission during the perinatal period (late pregnancy and childbirth) is very rare. Breastfeeding does not increase the risk of transmission to a child.

This disease is a major concern of the present time, not because it is a deadly disease, but because the illness is so benign initially that the infected persons may be completely symptom-free. The majority of the infected people will recover spontaneously. Only a minority will have major complications. Carriers of this virus can be identified by antibody testing and polymerase chain reaction (PCR) tests. Several years after the initial infection patients may present with cirrhosis of the liver or cancer of the liver. The treatment of HCV is expensive, requires medication administered by injections or oral antiviral tablets, given over a twelve-week period, in certain cases liver transplant is the only option. Since HBV infection is declining HCV infection has come more and more into focus. There is no vaccine against HCV.

Hepatitis D.
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HDV is a deadly virus but it either co-infects people at the time of HBV infection or infects people who are suffering from HBV disease; by itself, it is unable to infect healthy individuals.

There is no HDV vaccine.

Hepatitis E.
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This virus is a waterborne disease and spreads by contaminated drinking water. It is rarely transmitted from person to person. It infects younger adults in general, often those immune to HAV. It is suspected that pigs are the natural reservoir of this virus.

Vaccine for Hepatitis E is available only in China.

Hepatitis F.
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This virus may cause hepatitis in rhesus monkeys but has not been proven to cause any human disease. This virus is delisted as a cause of human viral hepatitis.

Hepatitis G.
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This is also known as GBV-C, named after G. Baker. It is an infectious virus to humans but probably does not cause human illness. It is transmitted by oral route and sexual contacts in HIV infected people.

It is thought that co-infection with the BG-C virus may actually slow the progression of HIV infection.

Several other viruses may also damage the liver, but the liver is not their primary target; and will not be discussed here.

Hepatitis means inflammation of the liver, not necessarily infection only. Many other agents including poisons, drugs, parasites, and our own misdirected immune system may seriously damage the liver.

Let us look at this aspect a bit closely:

1. Lupus hepatitis: (SLE) For some poorly understood reasons, some individuals may start directing the body's defense system against their own normal tissues and organs. In SLE liver damage is a significant finding.

2. Poisoning: By consuming poisonous mushrooms many people may end up in acute liver failure. Habitual drinking of African bush tea, a known hepatic poison, may lead to serious liver problems. Industrial poisoning by Carbon tetrachloride, a dry-cleaning agent, is a well-known hepatotoxin; so also, many other deadly gases are used in warfare. Suicidal attempts with ingestion of Copper Sulfate is common in some Asia countries, hepatic narcosis is not unusual in many such cases. Chronic Iron overload (in Hemochromatosis, repeated Red Cell transfusions) may lead to hepatic cirrhosis and liver cancer. A high dose of Paracetamol (Tylenol) may cause Liver failure.

3. Drug reaction: Many medications have significant adverse effects on the liver, and may produce reversible or irreversible damage to the liver. Some of the drugs are listed here.

Anti-Cholesterol: - Ezetimide, Statins.Fenofibrate, Gemfibrozil

Anti-TB: - Isoniazide, Refampin, Pyrazinamide,

Antibiotics: - Tetracycles, Oxycyclins, Chloramphenicol, Telithromycin, Trovafloxacin, Sulfanomide, Nitrofurantoin,  

Anti-Retroviral: - Abacavir, Nevirapine, Tipranivir,

Anti-Seizure-: Carbamazipine, Valproic acid, Phenytoin, Lamotrigine, Felbamate

Vitamins: - Vitamin A, Niacin

Ant- Diabetic: - Troglitazone, Pioglitazone, Rosiglitazone

Antifungal: - Ketokenazole, Itracoazole, Voriconazole

Antidepressant: - Duloxatine, Premoline, Nefazodone

Arthritis: - Aspirin, Declofenec, Rofecoxib. Leflonamide, Bromofenac, Benoxaprofen, Methtrexate, Phenylbutazone, Parafon forte.

Anti-Parkinson: - Methyldopa, Tolcapone

Anti- Cancer: Flutamide, Interferon beta1b, Imuran, Imatinib, Isotretinoin

Anesthetic: - Halothane

Acne: - Isotretinoin

Heart: - quinidine, Amiodarone

Asthma: - Zileuton, Zafirlukast,

Alzheimer’s disease: - Tacrine

Hyperthyroid: - Propylthiouracil, Methimazole

Diuretic: - Tienic Acid.

4. Parasitic diseases: Liver flukes (schistosomiasis) infect men when they eat uncooked fish. A bite of sand fly spreads Leishmaniasis (Kalazar). It is a chronic debilitating disease with hepatic enlargement. Amoebic liver abscess by Entamoeba histolytica in tropical countries is not uncommon. Humans acquire amoebic infection via the fecal-oral route and from the gut the ameba travels to the liver via the portal vein. By eating improperly cooked pork men acquire Echinococcus infection and may develop multi-loculated Hydratic cysts in the liver. Mosquitoes transmit Malaria. There are several families of malaria parasites; in some chronic stages of malaria, liver enlargement and dysfunction are common.

5. Leptospirosis: Liver necrosis is a common finding in its hepatic form. The disease spreads via the contamination of water by rats’ urine.

6. Q Fever: Drinking milk contaminated with   Rickettsia may cause serious liver damage.

7. Fungal infection: In disseminated Histoplasmosis liver damage is inevitable.

8. Bacterial infection of the liver is very unusual; however, an infection may spread to the liver from infected gallstones and bile ducts.

9. Alcohol: It is a curse of our civilization. So many people are addicted to this potent liver poison and heading for chronic liver diseases and serious health & social consequences. Alcoholics are less likely to recover when they contract other forms of hepatitis.

This is not a complete list. But if you are reading it, please pay attention and do not get into trouble.

 

edited 2020

 

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