Reply To: A Hello to Virology
The important findings:
1. That it is possible by subcutaneous injection of blood, or derivatives of blood, from a dengue patient to transmit the disease to a healthy non-immune, and from this case in a similar way to derive a series of experimental cases. In the present communication the original virus obtained from a natural case has been passed successively through four “generations” of artificial cases, with a doubtful positive case in the fifth “generation.”
2. That the virus under certain conditions may be passed through a Pasteur-Chamberland F. filter which at the same time is keeping back ordinary organisms (staphylococci, colon bacilli).
3. That the virus does not appear to be specially contained in any one element of the blood. Carefully washed corpuscles, citrated plasma, and serum free from corpuscles all contain the virus. It is not absolutely certain, however, in the case of serum that the virus may not obtain access to this by the breaking up of corpuscles.
4. That the virus is resistant to conditions outside the body for several days (99 hours).
5. That in the blood of the dengue patient the virus was present in one case 18 hours after the onset. in one case 67 hours and in another as late as 90 hours, whilst several cases show it to have been present at 57 hours and less after the onset. It was not found in a case 130 hours after the onset.
6. That the incubation period, while variable and not shorter than 41 days, is usually from 6 to 8 days, but may be as long as 15 days.
7. That immunity may be present to injection 229 days after the onset of a previous
attack of dengue.
So, again, the virus can pass through filters which stop bacteria. Also, it appears to pervade the constituents of the blood, but appears to only remain for a finite time after infection, after which immunity is established for some time.
So, again, the virus can pass through filters which stop bacteria. Also, it appears to pervade the constituents of the blood, but appears to only remain for a finite time after infection, after which immunity is established for some time.
But what of the particles?
The first reference I found to the viral particles (virions) themselves was in a paper from 1952:
“Research on Dengue During WWII”
https://www.ajtmh.org/view/journals/tpmd/1/1/article-p30.xml