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1.1.5 Highly Speculative Modes of Transmission



1.1.5 Highly speculative modes of transmission of HCV

The following are considered highly speculative because there have either been no studies, or conflicting studies. Or there is scientific reason to believe this is not a mode of transmission, but there still is no conclusive study to rule it out.

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1.1.5a Tears, saliva, urine, and other body fluids

“The presence of the RNA in the tear fluid was independent of the severity of the hepatitis and of the viral load as measured by the branched DNA assay...These findings suggest that tear fluid may transmit HCV but the source of HCV RNA in this fluid needs to be better understood.” (Med Virol. 1997 Mar; 51(3):231-3.)

HCV has been found in all body fluids, but not in all patients, and in varying amounts. The question remains as to whether or not the virus can be spread through these fluids. Blood in the fluids can definitely spread the disease, as with saliva from patients with bleeding gums. Another factor may be whether or not there are HCV-receptor cells in the mouth lining, and whether or not the body’s immune system fights off the virus in these quantities. (Oral Dis. 2005 Jul; 11(4):230-5.)

A report suggests that a health care worker contracted HCV and HIV from a patient. The worker had chapped hands, did not use gloves, and was in frequent contact with the patient’s urine and feces. (Am J Infect Control. 2003 May; 31(3):168-75)

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1.1.5b Cat scratches

It is unknown if the hepatitis C virus can be transmitted via cat’s claws if the cat scratches one person and immediately scratches another.

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1.1.5c Mosquitoes

Researchers have determined that the hepatitis C virus is not transmitted by mosquitoes. There is a lack of epidemiological or physical evidence that it is mosquito-borne and experiments to see any HCV replication in mosquito cells have failed.

There are two ways that mosquitoes can transmit illness to humans.

These are “mechanical transmission” in which a small amount of blood may be present on the mosquito’s feeding spike.

This type of transmission does not occur with serious human diseases such as HCV, HBV, or HIV. The second way mosquitoes transmit disease is called “biological” transmission. Studies show that mosquitoes can swallow viruses into their middle gut, but once there the virus dies and is digested in the same way we digest food - by breaking it down using acid.

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1.1.5d Alternative medical procedures

Alternative medical procedures involving invasive medical procedures, particularly those performed in nonmedical settings (i.e., acupuncture), or involving autologous blood (such as the ozone-enrichment of blood) may transmit the hepatitis C virus. (“Transmission of Hepatitis C by Ozone Enrichment of Autologous Blood,” Lancet, 1996; 347:541). A cross sectional survey in Japan found an increased risk of hepatitis C associated with acupuncture (BMJ 2000;320:513, 19 February).

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1.1.5e Household transmission

Household transmission of hepatitis C is rare. It can occur where blood-to-blood contact happens. This could involve a person’s blood spills coming into contact with someone’s open cut, or to a lesser extent, the sharing of razor blades, toothbrushes and sharp personal grooming aids. It is advisable to wipe up blood spills with paper towels and bleach, and to keep razors and toothbrushes separate from those belonging to other family members. Wiping a surface with isopropyl alcohol and leaving it to air dry will also kill the virus. (See 1.1.7c Cleaning Up Blood Spills)

A person can not spread the virus through hugging, touching, sneezing, or coughing, or sharing food, dishes,
or bathrooms.

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1.1.5f Unknown causes

A proportion of HCV infected individuals do not fall into any currently recognized risk group. It is thought that some of these cases may have had exposure to injected drugs or shared cocaine paraphernalia many years ago which they have forgotten or are unwilling to discuss.

It is possible that many persons were infected in the early 50s during mass vaccination programs in schools and camps. As well, programs for the poor often used cost cutting measures which included the recycling of medical devices (syringes, needles) which should have been thrown away.

Furthermore, blood products have been used in the making of many vaccines and in the 50s and 60s these products were not screened for HCV.

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1.1.5g Is HCV anything like HIV?

Both HIV and HCV are RNA viruses. Their genetic code is carried in RNA strands instead of DNA, like some other viruses. HCV is more like HIV than some other forms of hepatitis, but they are from completely different families. They have completely different strategies for replication and for survival.

HIV is a retrovirus, and once the virus is in a human cell it copies itself to DNA and migrates into the cell nucleus and integrates into the host genome and is then copied every time the cell copies its own DNA. Retro means that the virus reverts to a DNA virus once it is in the cell.

Other retro viruses are HTLV viruses like some types of leukemia.

HCV is a flavivirus. It is related to yellow fever and dengue fever viruses. It replicates by making positive and negative RNA strands and does not make DNA or integrate into the host genome.

There are lots of other structural and envelope differences between these two, but the main point is that HIV and HCV are NOT very similar at all—except they both completely screw up the immune system and there is no known cure. (See Double Jeopardy: The HIV/HCV Co-Infection Handbook).

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1.1.4d Hemodialysis

Hepatitis C FAQ

1.1.6 Prevention





 

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