CIDRAP - Finding of H5N1 in blood raises safety concerns

[KC]

Given the previous report of H5N1 RNA in blood, the virus's presence in blood "is not a new concept," he added. "But I believe this is the first time someone has taken the extra step and successfully cultured live virus out, or shown that there's live virus in the blood."

"The question is whether it's present when a patient is symptomatic or convalescent."

Similar questions arose with West Nile virus, which turned out to be detectable in blood before and for a while after symptoms, he added.

There should be a concern about vectors such as mosquitoes, ticks, deer flies, and horse flies. These vectors have been shown to be efficient in spreading several different forms of virus and bacteria. Two common vector borne illnesses from mosquitoes that come to mind are Chikungunya and West Nile Virus.

---------------------------------------------------------------
> From the CDC regarding West Nile Virus:

How Does West Nile Virus Spread?

- Infected Mosquitoes. Most often, WNV is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread WNV to humans and other animals when they bite.

- Transfusions, Transplants, and Mother-to-Child. In a very small number of cases, WNV also has been spread through blood transfusions, organ transplants, breastfeeding and even during pregnancy from mother to baby.

- Not through touching. WNV is not spread through casual contact such as touching or kissing a person with the virus.
------------------------------------------------------------------

The information and research on West Nile Virus was kick started when the disease entered the United States. The current research on how West Nile Virus spreads looks very similiar to current HIV spread without the mosquito vector or sexual contact links.

There are some researchers who think the widespread HIV and AIDS problem in Africa is contributed to by vectors, while the United States has ruled out this possibility. There are also some researchers who are considering whether such diseases as Chikungunya and West Nile Virus could be spread by sexual contact.

All of these ideas are plausible. More research is needed as the viruses emerge and change.

[Shannon Bennett]

Re: CIDRAP - Finding of H5N1 in blood raises safety concerns

I'd like to ask a question here. If the virus is circulating in the blood, doesn't that mean it is able to find cells throughout the body to infect? If this virus has now managed to shift its preference to lower temperatures (as repoted in todays news), doesn't this then open the doors to many other parts of the body being ovewhelmed with the virus? Maybe I should back up a bit. If this virus, like the virus in 1918, was able to infect both the upper and lower lungs and airways, isn't the movement of the virus through the bloodstream a way to facilitate this infection?

[KC]

Re: CIDRAP - Finding of H5N1 in blood raises safety concerns

Pretty scary thought Shannon. I don't know if anyone knows the answers yet or ever will. More research is needed.

The 1918 virus was very hemorrhagic in nature. Dr. Taubenberger was the first person I know of who actually began studying the past rigorously to find the answers. Back then, it was H1N1 due to his research. I believe the best web source for the 1918 pandemic has been compiled here.

Reports of the emerging H5N1 having the same characteristics... ie. multi-system organ failure in some cases... is something to be looked at.

I would like to know what the viral load was in the patients that were sampled. If they were not highly viremic and just circulating a small amount of virus in the blood, I would be less concerned (I am not a professional and just my honest opinion).

If the patients were highly viremic, I would be concerned about vectors enhancing the spread. I would also be concerned with the potential spread of the virus through non-traditional means such as blood transfusions, organ transplants, mothers milk, child birth, and possibly even sexual intercourse.

I would also like to know more about the NA antigen. It seems most of the research over the years has been concentrated on the HA antigen. Also, lots of research has concentrated on only one virus or family of viruses; Very little has been studied on the interaction between various virus families, bacterias, or mycosis'.

[AlaskaDenise]

Re: CIDRAP - Finding of H5N1 in blood raises safety concerns

It appears to me that this is a repeat of 1918's ability to circulate in blood. It's just using a different technique. In 1918, it was plasminogen (blood enzyme) binding due to the NA deletion that caused the HA to cleave anywhere blood circulated.

I have assumed (please someone correct me, if I'm wrong) that the multi-amino-acids at the HA cleavage also allowed many substances (those umbiquous proteases) to cleave the HA, then allowing the virus to circulate and infect different organs.

Are any of the umbiquous proteases in the blood?

I understood the point of Kawaoka's study on upper/lower lung replication was that it was dependent on it's RBS ability.

I was reading about the importance of the neuraminidase somewhere (cannot find it), and it mentioned that the NA action here was a strong "scrubbing" of the sialic acid on ciliated cells in the epithelium, which set the stage for a secondary bacterial pneumonia. It mentioned that the fluid in this process allowed infections to travel easily in this area. I wonder if that would apply to the H5N1 also - giving it an additional method of spread in that respiratory area.

I really have looked for that paper & can't find it. Maybe someone else has that reference - it's a good paper.

.

[AlaskaDenise]

Re: CIDRAP - Finding of H5N1 in blood raises safety concerns

Strong scrubbing issue:

is it possible that the "strong" scrubbing action is due to:

high cleavability = high viral load = high NA sialic acid scrubbing incidence???

If that were true, then the need for anti-virals might be reduced by using HA "blockers." (stretching out a scarce resource)

.