Your Friendly Neighborhood Live Vaccine

A really intriguing study suggesting a non-specific general health effect of live vaccines was just published in JAMA. 

The study compared a half million children immunized with the MMR vaccine as their most recent vaccine compared to DTap-IPV-HiB. The hypothesis tested was that MMR, with its live components, would have a non-specific immune enhancing effect due to greater immune stimulation than with the killed vaccine. To assess this the incidence of hospitalization for any infection was determined.

The researchers found a statistically protective effect (IRR 0.86) with those who received MMR as their most recent vaccine.

What this study may have uncovered is a non-specific immune boosting effect of live vaccines. If true, it may mean that live vaccines should be placed in the immunization schedule at the times most opportune to provent childhood morbidity, as suggested by an accompanying editorial.

Further, the animus that the anti-vaccine movement has against live vaccines has again shown to be completely unfounded and not reality based. 

Rat Bite Fever, Buyer Beware

A fatal--and rare--infection that killed a San Diego boy reinforces an important fact about infectious diseases: they are often zoonotic. A zoonotic infection is one that arises from a species jump. HIV is a zoonosis from chimpanzees, rabies is a zoonosis from dogs, and in this case, Rat Bite Fever is a zoonosis from rats. 

Rat Bite Fever is a rare illness caused by a bacterium known as Streptobacillus monilliformis and it is fatal in about 20% of cases. Plain penicillin is all that is needed to abort the infection, if the disease is recognized. 

Rats carry the bacteria without symptoms so it's not obvious if a rat is infected or not. As such, caution is advised when handling rats (use gloves), especially in those with an immunocompromising condition. 

This fatal case has sparked a lawsuit against Petco but I can't imagine they are unequivocally to blame for this tragic occurrence. 

Ghostbuster For Life

Although I had no personal connection with Harold Ramis, his recent death from autoimmune vasculitis is tragic to me. Mr. Ramis' work in Ghostbusters and Ghostbusters II affected me in an unequivocally positive manner. 

As a child growing up in a region rightly dominated with the likes of Terry Bradshaw, Franco Harris, Lynn Swann, Roberto Clemente, Willie Stargell, and Mario Lemieux, I longed to find heroes to whom I could fully relate. Of course Jonas Salk, Andrew Carnegie, Henry Frick, and George Westinghouse were also figures who loomed large, they were, however, from prior eras or not readily available. 

Onto the scene came Ghostbusters in 1984. While the premise of grown men fighting ghosts might seem silly, it was the romanticism of the movie that irrevocably captured me as 9 year old child. 

Scientists saving the world by using their extreme intelligence to face the unknown was something that totally captivated me. This was a world I wanted to (and want to) live in. I can remember scouring college catalogues looking for a "parapsychology" major. Even today, when I hear songs from the movie I can't help but feel admiration for the fictional heroes of the film (embarrassing confession: I get very psyched up when Bobby Brown sings "You try to mess with my boys, that's not legal" in the theme from Ghostbusters II)

In many ways, I believe my passion for infectious disease was--in some small part--motivated by a love for the movie. While microbes are real entities, battling them can be thought of in a similar vein as the travails of the Ghostbusters. 

As an infectious disease physician facing much less daunting tasks than the end of the world, I think of myself, perhaps foolishly, as being in the spirit of Dr. Egon Spengler, Dr. Peter Venkman, Dr. Ray Stanz, and Winston Zeddemore (paradoxically actor Ernie Hudson actually has a PhD). And, when I don my Ghostbusters t-shirts or my white coat--a few degrees less powerful and cool than a proton pack--I feel a kinship with 4 heroic characters that will be with me always. 

Polio-like Illness in California?

A few points regarding the cases of paralysis linked to enterovirus 68 in California:

--Enteroviruses are a large group of viruses that cause diseases ranging from the common cold to paralysis

--Polio itself is an enterovirus and in an era in which polio is almost eradicated, it is not surprising to see another enterovirus causing paralytic illness

--These cases are a rare manifestation of a rare virus

Overall, the identification of these cases is important because it illustrates the benefit of surveillance in combating infectious diseases. Future work should focus on understanding the true burden of this disease and determining what percentage of illness proceeds to paralysis.

I'm supposed to discuss all this on John Seigenthaler's show shortly. 

Lurking in Tap Water

An interesting case I was involved with over the past week illustrates the ubiquity of microorganisms and their ability exploit to any weakness to cause infection.

A guy falls off a ladder, tears his meniscus, and has surgery. Pretty routine until he develops a cystic mass at the surgical site. It's excised and grows Mycobacterium kansasii, a bacterium which is related to tuberculosis and merits aggressive treatment. 

How does one get such an organism at a routine surgical site? Tap water.

Of course, not everyone's wound gets infected by this relatively rare bacterium so there is likely a large amount of host susceptibility at play. In fact, M.kansasii really gained prominence during the early years of the HIV/AIDS pandemic. While untreated HIV/AIDS causes catastrophic immune collapse, subtle alterations in an individual's immune repertoire are likely all that is needed when a the bacterium comes into contact with a hospitable wound.

The fact that such a pathogen flourishes in tap water reinforces the fact that we live in a world populated by microbes and that sterility is only relative. So, when a new mother lunges after her toddler when he drops his binky so she can wash it in the sink her activity just replaces one set of microbes with another.