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Thanks for the Plague, California!

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black_death

Because if hiding dead bodies isn’t a conspiracy, we don’t know what is.The bubonic plague (and its’ siblings, the septicemic and pneumonic plagues) is alive and well in the Western United States.  In fact, in the most plague-stricken region in the United States (Northern New Mexico) several cases pop up every year.  Even with modern antibiotics, nearly 1 in 6 plague patients will die – which is still better than no treatment at all, since some forms are 99% fatal if untreated.

Thanks to horizontal gene transfers and other mechanisms, soon antibiotics may not even help: one recently isolated strain of the plague was found to be resistant to eight antibiotics, including all of the three primary treatments for plague.  Even more disturbing, a Nevada woman who eventually died was treated for a bacterial infection in early 2017 that was resistant to every antibiotic available in the United States.  Yersinia pestis typically hides out in long-term environmental reservoirs, which may provide more opportunities for horizontal gene transfer and makes eradication of the plague almost impossible in the Western U.S. (or other countries).  This makes the average 10 to 20 annual cases in the U.S. largely unavoidable.cycleThe plague is not native to U.S. soil and its’ presence here was neither inevitable nor even especially difficult to avoid.  The plague made landfall in San Francisco’s Chinatown, where deaths started occurring around 1900.  Under the direction of the governor of California, Henry Gage, the bodies of plague victims were hidden for at least two years.  In fact, over 100 deaths were concealed, and newspapers reported that the plague “Did not, nor ever did exist in California.”  The San Francisco Examiner even ran an article :Why San Francisco is Plague-Proof.”

Why hide such a deadly disease from the public?  Greed, pure and simple: Gage and his officials feared the loss of revenue during quarantine, and an even more significant loss of revenue if consumers stopped buying California produce, which was by then a burgeoning $25 million dollar industry.  Despite the attempts by the governor to silence the medical community and corrupt the media, a handful of champions of public health eventually succeeded in ridding the city of the plague.  Two of the city’s most prominent physicians, Wilfred H. Kellogg and Joseph Kinyoun, Chief Bacteriologist and Chief Quarantine Officer,  made valiant efforts to protect the public welfare that did not immediately come to fruition.  After discovering Yersinia pestis in the blood and lymph smears from infected corpses, these doctors made recommendations to contain the outbreak.  The response from California State officials was swift and merciless:  the doctors were fired and massive, devastating smear campaigns were launched against them in the local media.

Still, by 1903 the political tide started to turn against the Governor, and after repeated outbreaks in 1906 and 1908, the plague was eradicated from the city of San Francisco.  The same newspapers that had denied that the Black Death had ever descended on San Francisco now gleefully declared that it had been eradicated.

Unfortunately, while the cleanup-up was a win for San Francisco, lasting damage had been done to the Western United States.  Local populations of mammals, including rats and squirrels had already been infected within the first several years due to the critical delays in treating and containing the outbreak.  Over half of all plague related deaths in the United States now take place in a region that had nothing to do with the introduction of the disease.  Free-ranging animals have spread the disease, until at last, it found its’ greatest permanent reservoir in the United States: The Gunnison and black-tailed prairie dogs of northern Arizona, New Mexico, southern Colorado and Utah.

These regions overlap with the distribution of plague hotspots in the United States, and not just for humans either: over 90% of the inhabitants of an infected prairie dog town will usually die in a single outbreak.  Fleas jump from their dying hosts in favor of dogs (who seem to be plague-resistant) and enter homes where they kill both humans and cats (who seem to be especially vulnerable).  Thus, Henry Gage’s legacy repeats itself, claiming more lives every year, and reminding us that the consequences of inaction during a pandemic are severe, while the consequences of actions taken to deliver misinformation during a pandemic are abominable.

[2] Tansy, T. Plague in San Francisco: Rats, Racism and Reform.  2019  Nature. https://www.nature.com/articles/d41586-019-01239-x.

[3] Plague Ecology and Transmission. United States Center for Disease Control (CDC) webpage.  See infographic, vide supra. https://www.cdc.gov/plague/transmission/index.html.

Anti-Vaxxers a Top Health Threat

By | Blog

A new threat to the health and safety of children has recently begun to take center stage: diseases that were once thought eradicated have reemerged into public consciousness.  These diseases have been aided and abetted by the irresponsible and dangerous behavior of people opposed to vaccines, otherwise known as anti-vaxxers. Read More

Toxoplasma Gondii: The Brain Hitchhiker

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kitty3Toxoplasmosis is a widely known disease that results from infection with the Toxoplasma gondii parasite, one of the world’s most common parasites. Infection usually occurs by eating undercooked contaminated meat, exposure from infected cat feces, or mother-to-child transmission during pregnancy.  Estimates suggest that about 1/3 of the entire human population of the Western world is harboring the parasite in the form of “benign cysts” concentrated mostly in the brain.

The parasite can form cysts anywhere almost: hearts, lungs and eyeballs are common hiding places, but the brain is the preferred hangout for this organism.  If you are a cat lover, chances are high you are already infected, courtesy of your cat.  Cat brains are a natural repository for the adult protists, which reproduce inside our feline friends and spread from cat feces.  This is not to say that won’t infect any warm-blooded animal that they are capable of, but the only hosts truly necessary for their continued survival are felids, according to the CDC website.  Once infected, they usually infect you for your entire lifespan, mostly asymptomatically.toxo

The most interesting thing about the infection, though, is that the cysts hijack our brains, producing subtle but measurable and influences on behavior.  Scientists have suspected that the success of Toxoplasma is due in part to its’ ability to change rats and mice behavior, and causing them to stop fearing cats.

In a now famous study, it was demonstrated that mice, which have a morbid fear of cats and a strong fear reaction to cat odor, tend to lose that fear and unequivocally show a preference for cat odor after being infected with the parasite.

Mice aren’t the only ones whose brains can be hijacked, though: there’s a good chance that the parasite in your head may be at least partly responsible for the shots you call, too.  A growing body of research indicates that the manipulation theory, as it is called in medical and biological journals, extends to human in several ways.  Latent toxoplasmosis in humans has been associated with serious neurological disorders, including schizophrenia, intermittent explosive (rage) disorder and suicide.

In addition, research shows infection by Toxoplasma gondii, directly affects the production of dopamine, a key chemical messenger in the brain.  Dopamine is a natural chemical which relays messages in the brain controlling aspects of movement, cognition and behaviour. It helps control the brain’s reward and pleasure centres and regulates emotional responses such as fear. The presence of a certain kind of dopamine receptor is also associated with sensation-seeking, whereas dopamine deficiency in humans results in Parkinson’s disease.

Infection changes the way that your brain processes information, slowing reaction times (more traffic accidents) and changing your preferences for a great many things, from risk aversion to tidiness to extraversion.  The effects of Toxoplasma infection on an individual depend on genetics, with some genotypes immune to infection and less likely to experience effects, and gender.  To take one example, the effect on personality has been summed up after analyzing multiple studies, each with well over a hundred (and often several hundred) subjects.

According to Effects of Toxoplasma on Human Behavior, significant differences in personality factors were found between Toxoplasma-infected and -uninfected subjects in 9 of 11 studies, and these differences were not the same for men and women. After using the Bonferroni correction for multiple tests, the personality of infected men showed lower rule consciousness and higher vigilance. Thus, the men were more likely to disregard rules and were more expedient, suspicious, jealous, and dogmatic. The personality of infected women, by contrast, showed higher warmth, suggesting that they were more warm hearted, outgoing, conscientious, persistent, and moralistic.

Even sexual characteristics and preferences might be affected.  In one photograph study, men who harbor infections are consistently rated as being more dominant and masculine looking then men who don’t have infections – on the basis of photographs alone.  Toxoplasma increases expression of the genes coding for testosterone in men, and the effect is large enough to be seen by the naked eye and borne out by physical measurements, including a noticeable 3 cm boost in average height.

Although the mechanisms by which this parasite seems to influence its’ hosts are still being elucidated, its’ clear that it touches our lives in ways we never before imagined.  How much of “them” is really “us”?

Anti-Cancer Gut Bacteria

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The human microbiome is the subject of a burgeoning field of research.  The effect of gut microflora, and especially bacteria, has in the last few years been linked to anxiety, depression, gastrointestinal and autoimmune diseases, and numerous other disorders. Read More

New Genetic Test for Antimicrobial Resistance

By | disease, research, antibiotic

how-bacteria-work-360x240You’ve most likely taken an antibiotic at least once in your lifetime. From treatments for painful strep throat or ear infections as a child, to burning urinary tract infections or itchy skin infections, antibiotics are one of the most highly utilized and important medication classes we have.  Soon, your doctor may have a new weapon in their arsenal to diagnose and target treatment:  scientists at American University have developed a rapid, highly sensitive genetic test to determine whether bacteria carry a gene that causes resistance to two common antibiotics. Their research, published in BMC Infectious Diseases, demonstrated that the new test works as accurately as culture-based methods but gives results in minutes, not hours or days.

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