Entourage: Concretizing the Disease Dynamics in Concurrent Sexual Networks

A diagram showing how  concurrent sexual relationships foster the spread of HIV

Last night I watched the movie Entourage, which is based upon the HBO television program of the same name in which the exploits of a rising Hollywood star and his hometown "entourage" are detailed.

I didn't expect to find an important infectious disease topic in the movie but I am always on the look-out and--sort of fitting for a Hollywood star-focused movie--concurrent sexual networks came up when one character is put in a dilemma when his two concurrent sexual partners find out about each other and one of whom reveals she has a sexually transmitted infection which is assumed to be genital herpes.

Concurrent sexual networks are a pattern of sexual contacts that involve having more than one sexual partner at a time, as opposed to the serial monogamous relationships. While the number of total sexual partners over a specific period of time may be equivalent between an individual in serially monogamous relationships and one who is concurrent sexual relationships, the infectious disease implications are very different. 

Concurrent sexual relationships dramatically increase the ability of a sexually transmitted infection to find new hosts, especially if the other partner also is involved in another concurrent sexual relationship. Amplification of spread is much more easily achieved in such a scenario.

It was study of the explosive nature of the HIV epidemic in Africa that really concretized the importance of concurrent sexual relationships and informed the "zero grazing" campaigns.

While a zero grazing policy may be anathema to the Hollywood elite depicted in the movie, it is fuel for the sexually transmitted infection fire. 

MERS Storms the Korean Peninsula

As the outbreak of MERS cases in South Korea continues it appears that what is responsible for the 30--2 of which have been fatal and one of which was imported to China--is a combination of lax infection control coupled with a possible super-spreader event. This camel and bat-linked coronavirus, which has killed about 36% of the 1200 people it has infected thus far, has now been reported in 16 nations (including the US for those of you who have forgotten). 

To recap the events: mid-May a man who traveled to the MERS epicenter, the Middle East, returned to South Korea and was subsequently diagnosed with MERS. Being the 1st MERS case in South Korea and with a consequent delay in diagnosis patient's who were co-located were exposed and infected (primary transmission) then went on to infect others (secondary tranmission) who then went on to infect others (tertiary transmission, which has been confirmed in 2 cases).

This cluster, which is exclusively hospital-based thus far, has vaulted South Korea to the #3 MERS country, behind Saudi Arabia and the UAE.  Such a cluster reinforces the need for meticulous infectious control when dealing with a respiratory virus like MERS that has proven adept at exploiting lapses in infection control. South Korean authorities have since apologized for their handling of the initial stages of this outbreak which have led to over 1300 people being monitored after contact with case patients. 

Also, the index patient is responsible for infected at least 11 (maybe 22) other individuals (Ro = 11 - 22) clearly putting this man in the category of a super-spreader as his disproportionate contagiousness has clearly fueled this outbreak (similar to what occurred with the related SARS in 2003).

These events have, understandably, provoked fear in the South Korean populace and have prompted school closures as well as a travel alert in Taiwan. 

It is important to remember, at this stage, that no community transmission has occurred in South Korea and, though it is a possibility, swift action on the part of public health authorities can extinguish the outbreak. What also must be emphasized to clinicians world-wide is that MERS (and other infectious diseases) can appear anywhere and, to paraphrase Louis Pasteur, prepared minds are the ones that are lucky enough to discover them before too much damage is done. 

Could it Be "Lime's"? Lyme Disease & Some Thoughts on Diagnosis

One of the benefits (or drawbacks) of practicing medicine in Western Pennsylvania is that we're in the middle of an area in which Lyme Disease is highly prevalent. This prevalence has caused the general public to be very aware of Lyme Disease (or, as they call it, "Lime's Disease"--a phrase that instantly makes me cringe both for the mispronunciation and for the abyss I am about to descend). Such an awareness, in many ways, has mixed results. On the one hand, an informed patient is unequivocally better than one who is not: it can make diagnosis and treatment much easier as well as help with public health messaging regarding  precautions needed to take to avoid ticks. However, the general public is often unable to sift through all the misinformation about Lyme that exists and understand when it is truly a possibility and when it is arbitrary to suggest its involvement in an illness (let alone responsible for "chronic" symptoms).  I recently was asked to test for Lyme disease in a person with stroke symptoms.

Because Lyme disease has various stages and varied symptoms, many people have heard anecdotes about someone they know with mysterious symptoms that were eventually found to be due to Lyme disease. However, what must be kept in mind is that though there are rare cases of many conditions that have been shown to be the result of Lyme disease, they are a rarity and testing for Lyme disease in the absence of a real suspicion of a role for Lyme can lead one down the wrong path. It must be remembered that at least 10% of people with positive Lyme results have had asymptomatic infections and a positive antibody test will be meaningless if just tested as part of a "shotgun" approach to diagnosis.  

Chances are that any given person's stroke is caused, not by Lyme, but by atherosclerosis--indeed a major study on this topic said Lyme testing added "little value". The same is true is for the myriad other conditions that often get blamed on Lyme. This is not to say that Lyme isn't capable of being behind someone's nebulous symptoms, just that many people (physicians included) seize on Lyme when they're looking for a quick and easy answer.

Return to Sender: The Biosafety of Unknowingly Shipping Live Anthrax

The NY Post front page during the 2001 anthrax attacks

A couple of things to note regarding the mistaken shipment of live anthrax spores from Dugway Proving Grounds in Utah:

• The biggest concern, to me, is that there was a failure to know what was being shipped. Live anthrax spores can be shipped, but must be done in a proper fashion to prevent package damage as well as to assure that those who receive it are prepared (e.g. vaccinated, appropriate lab setting)
• Why did irradiation fail in this setting?

I don't believe anyone will be sickened by this lapse (those exposed who were not vaccinated are received post-exposure prophylaxis) but it is concerning chiefly because there clearly is a biosafety problem that remains at the nation's labs and each lapse, when it is splashed across the front pages, alarms the public who understandably may begin to question what is very vital research.  

Meticulous biosafety at government labs tasked with doing such important research is essential given that the FBI's (somewhat disputed) conclusions regarding the source of the anthrax employed during the Amerithrax attacks (see an interesting new twist on this here). 

Lassa Fever Slithers Through Ebola Monitors

By now, most people know of the imported, and ultimately fatal, Lassa Fever case in New Jersey in a traveler from Liberia. This isn't a cause for panic and we've dealt with Lassa importations several times before and though there are many overlapping symptoms between Ebola and Lassa, Lassa is unequivocally more benign.

To me the most fascinating aspect of this case is how this man's travel history was not fully known to treating clinicians in the state in which Kaci Hickox was unjustifiably quarantined during the height of the Ebola hysteria. There's a great New York Times piece on this part of the story. A few important timeline highlights:

• The man arrived at JFK airport on May 17 from Liberia via Morocco (presumably passing exit screening in Liberia)
• He deplaned and was not febrile during his entry screen at JFK
• His case was passed off to local health officials in New Jersey for active monitoring
• The man developed fever and sore throat prompting a visit to an emergency department where he was treated and released on May 18. 
• He was unable to be contacted by health department officials on May 18
• He was reached on May 20 and May 21 and was apparently without fever
• He represented with worsened symptoms on May 22 and was admitted
• He died on May 25

There are important implications that arise from the New York Times piece that include:

• Did the health department in New Jersey know of the patient's visit to the hospital on May 18 at any time prior to his readmission?
• How are hospitals to know and have situational awareness of who is under active monitoring if the patient doesn't volunteer that information? 
• All public health response systems require cooperation from the public for optimal function

These events should prompt a re-examing of the current system and emphasize the importance of emphasizing a travel history be taken in all patients with infectious syndromes whether they may have come from Lassa-laden West Africa or Legionnaire's Disease laden Pittsburgh. 

In a more stigmatizing and prejudicial time, bells were unfortunately tied around lepers to warn others of their approach. Such an approach was and is unnecessary for a better alarm bell is simply taking the travel history.