Post-Lyme Syndrome: The Result of Altered Immunity, not Chronic Infection

One of the controversies in infectious diseases surrounds Lyme Disease. There is a large group of patients who, once adequately treated for the infection, continue to experience symptoms such as chronic pains, malaise, and related complaints. 

Although patients--and some clinicians--attribute this to ongoing replication of Borrelia burgdorferi, there is no evidence that a chronic form of infection amenable to antimicrobial therapy exists. A recent paper has shown that some Borrelia antigens may persist in a mouse model, but that does not mean long term antimicrobial therapy is warranted or beneficial in humans. The IDSA guidelines, which unfortunately continue to spark controversy, reflect this position.

Many infectious disease physicians believe that post-Lyme symptoms are the result of the specific immune constitution of individuals and, as such, prolonged antimicrobial therapy offers no benefit as clinical trials have shown.

A recent study, published in Clinical Infectious Diseases, attempted to assess if there are  immune differences in those that experience chronic Lyme symptoms. One of the fascinating results of this study was that, even prior to treatment, those that develop chronic Lyme symptoms have an altered polarity of their immune system when compared to those who suffer no chronic symptoms. Specifically, elevations of IL-23, a molecule which promotes the proliferation of Th 17 T cells, a specific class of immune cell linked to the development of autoimmune phenomena, were found to be associated with the development of chronic Lyme symptoms. One caveat: the study was conducted in Europe where B.afzelii is the culprit bacteria, which may limit its generalizability to the US setting.

The importance of this study is that it will, hopefully, dissuade those who demand chronic antimicrobial therapy from such requests while, at the same time, point the way towards fruitful areas of research that may yield effective treatment.

Apollo 18: Contagion on the Moon?

The movie Apollo 18, a sci-fi movie that portrays a horrific mission to the moon, addresses some important microbiological and infectious disease matters (albeit in a highly fictionalized manner). In the film, astronauts on a moon mission are infected/infested by an extraterrestrial pathogen.

The scenario of a contagious disease in space raises very difficult questions, some of which have been the subject of actual prior work in this field. Some fascinating questions include:

• Does being in space where sterilized food is consumed change one's microbiome to render one hypersusceptible to infection (either extraterrestrial or upon return to Earth)? The historical answers to this question and the possibility of astronauts being at a risk from a "fatal kiss" are discussed in the book Good Germs, Bad Germs.
• What would be the concept of operations in an extraterresterial infection (see Michael Crichton's The Andromeda Strain)?
• How does one handle a potentially contagious illness in an astronaut in space? 
• Is there bacterial life on other planets, asteroids, etc? Would they resemble earthly extremophile bacteria?

While movies such as this are pure fiction, they do serve to focus attention on the ubiquity of microbes and their ability to infect us in myriad scenarios. 

Starve the Flu, Have a Fever

An interesting new study published in the Proceedings of the Royal Society B (summarized in The New York Times) , using mathematical modeling tools, suggests that medications that reduce fever may amplify the ability of the virus to spread. 

Fever, as unpleasant and disabling as it is, serves two purposes with respect to infectious disease.

1. Usually, microbes are unable to reproduce at the higher temperature that characterizes fever.
2. The unpleasantness of fever often limits social contacts, starving the microbe of new hosts to infect. 

Consequently, when fever is controlled the propensity of the microbe--in this case influenza--is enhanced by 1-5%. Taken at a population level such a minor increment can translate into a substantial number of added cases. 

The results of the study while intriguing and logical, must be placed into context. Fever, though usually benign, can have serious consequences such as febrile seizures in children and increasing the metabolic demand, which could prove dangerous in someone with compromised cardiac or pulmonary function. 

Bottom line: Be cognizant that reducing fever helps the virus but may be a necessary action when the entire context of the patient is taken into account.

Would Penguins Taste like Chicken to Bird Flu?

In the movie Mr. Popper's Penguins there's a scene in which the main character and his family are "rescuing" a group of penguins from the zoo. As they leave, they yell something to the effect of "arctic bird flu infectious disease emergency!" to facilitate their escape. 

While penguins can contract influenza, they are not the main concern with respect to a future bird flu pandemic as their exposure to humans is minimal. 

Currently, mankind is faced with dual threats from avian influenza: H5N1 and H7N9 (though other avian strains have kept into humans). These viruses, contracted by poultry exposure, have extremely high mortality rates but have not been able to spread efficiently between humans--the precondition for a pandemic.

H7N9 has been a relatively new threat that emerged in 2 waves in China (with subsequent cases imported to Taiwan) beginning last year. To date 238 cases have occurred with 57 deaths. This past week, China reported 45 new cases. 

In its latest risk assessment, the WHO anticipates more human cases possibly tied to the celebrations associated with the Chinese Lunar New Year celebrations, which will involve larger scale transportation of poultry. The ability of the virus to gain the ability to spread from human to human is unlikely.

Unfortunate for us, viruses like H7N9 reside in bird species with which humans have regular contact and not penguins--no offense to the natural or Pittsburgh variety. 

Polio Wars: Dying for Vaccination in Pakistan

I discussed, in a prior post, the progress of the global polio eradication effort. Last year marked a major setback in the eradication effort as 9 countries reported 389 cases. Though not even a month old, 2014 has already seen 4 cases occur--all of which are located in the North Waziristan region of Pakistan. 

It is no accident that Pakistan remains the biggest obstacle to polio eradication given the continued murderous violence Taliban Islamists direct at polio vaccinators. Since July of 2012, 33 individuals associated with the vaccination effort have been killed. 

The contrast between those who are working to improve human life by working to eradicate one of mankind's scourges from the planet and those who seek to relegate mankind to a state in which polio is allowed to spread with abandon couldn't be starker.