House S7EP07 “A Pox on our House”
Wow! Two infectious disease premises two weeks running! The premise here from the Fox.com House site: a 200-year old jar from a shipwreck breaks in the hands of teenage girl’s hands. She then exhibits the signs and symptoms of smallpox, and it’s off to the hospital. This prompts the Centers for Disease Control to get involved, who of course come into conflict with our team of intrepid heroes. The TV promo spots for the episode show House breaking quarantine to get access to the patient, putting himself into mortal danger. Will he be OK, or will the show be called “Wilson, MD” next week as we change to a new Point-Of-View character?
Smallpox, also known as variola virus, is member of the viral family poxviridae, a group of double stranded DNA viruses according to the Baltimore classification scheme. Poxviruses are enveloped viruses, which means that the virus is surrounded by a lipid containing membrane formed as the virus is synthesized and released by an infected cell. If we recall back to our chapter on microbial control, we were presented with a chart which showed the relative susceptibility of various pathogens to physical and chemical control methods. What is typically observed is that viruses show a range of susceptibilities to control measures, and that viruses possessing an envelope are typically significantly more fragile than non-enveloped viruses. That is, an enveloped viruses will persist in the environment for a shorter period of time than a non-enveloped virus. According to this article obtained by searching Pubmed, a 99 percent decrease in virus titer (a measure of the amount of infectious virus particles) was observed under experimental conditions over a 10 year period. And the Wikipedia summary states:
The lipid bilayer envelope of these viruses is relatively sensitive to desiccation, heat and detergents, therefore these viruses are easier to sterilize than non-enveloped viruses, have limited survival outside host environments, and typically must transfer directly from host to host.
Worldwide outbreaks in smallpox free regions throughout the middle of the 20th century were invariably epidemiologically traced to individuals who had brought the pathogen and the disease from areas where the disease remained endemic prior to its eradication.
Recall the premise of the episode: a 200-year old jar from a shipwreck, with viable variola major virus particles. What this means is that effectively the premise in this episode is extremely far fetched. So prior to watching the episode, my B.S. meter is pretty far off the scale.
UPDATE 8:55 PM Monday: Final Diagnosis Rickettsialpox. Wow! This is really timely after today’s lecture. Rickettsialpox is a disease transmitted by the bacterium Rickettsia akari, a member of the group of the Rickettias described today, of which the major disease presented in class was Rocky Mountain Spotted Fever. Rickettsialpox is described as a relatively benign disease with a 2 to 3 week course if untreated, and is readily treated with an antibiotic such as doxycycline. Like RMSF, rickettsialpox requires an arthropod vector for transmission, and is NOT a directly communicable disease. Wikipedia notes that there have been no known deaths from rickettsialpox. My final verdict: Bogus!