Sunday, August 30, 2015

Jail-house Cough

When the world of somewhat rare infectious diseases collides with prison and inmate issues, it causes an uproar of excitement in my house. Education and advocacy are large themes in my marriage. It's obvious that STEM education is my driving force, but my husband focuses his efforts on issues associated with significantly skewed stigma and underrepresented topics, such as advocacy for mental health patients and inmates. He actually teaches a class on prison issues at UC Berkeley, and leads a volunteer group that takes UC Berkeley students into San Quentin Prison to tutor inmates that are working towards obtaining a GED. Its not uncommon that he will have to cancel volunteer shifts due to prison-wide lockdowns (most often due to fog), but Thursday night's lockdown had us talking.

As I've mentioned before, prisons are an epidemiological hotbed for infectious diseases. Sticking a large number of people in small, confined communal living quarters with inadequate medical care is one of the fastest ways to allow diseases to spread. So, hearing that the lockdown on Thursday and Friday were due to the potential spread of disease, we were not alarmed. When we heard it was Legionnaires' Disease and that one case had been confirmed with 30 other inmates presenting symptoms, we were surprised.

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Image from PrimeWater Membranes


Legionnaires' Disease, or "legionellosis", is a bacterial infection caused by Legionella spp. (most commonly Legionella pneumophila) and leads to the development of atypical pneumonia. Legionnaire's disease is most well known for its debut in 1976, when a L. pneumophila epidemic was traced back to the Philadelphia Convention of the American Legion. More than 30 people died as a result. Yet, L.micdadei had already been isolated from human blood in the mid 1940s. As usual, only a handful of disease nerds care about a disease before an epidemic occurs.

These two, specifically. (Credit: Wikipedia)
 Legionnaire's Disease is spread through droplets of water containing the bacteria, especially in warm environment that cause steam and aerosolization, like showers, hot tubs, wet saunas, humidifiers, and faucets.The CDC also lists "decorative fountains" as a potential source, which, I have to admit, made me laugh. I mean, think about all the major hospitals that have massive decorative fountains in their entrance/courtyards! Double threat!

Legionella spp. have developed a somewhat symbiotic relationship with larger protozoae, such as amoebas, that create large biofilms that can protect the Legionella bacteria. Outbreaks are most common in places that house lots of people for extended periods of time, like hotels, office buildings, retirement homes and convalescent facilities, hospitals, cruise ships, and prisons. Legionella spp. also like to live in wet soils.  Despite the dependency on aerosolization for transmission, Legionnaires' Disease is not spread from person to person. A reservoir, like water or soil, is required for the transmission of the disease.

Amoeba engulfing and releasing bacteria. (Via Pall Corp.)
 If you inhale contaminated water, the bacteria travel through your respiratory tract and into your lungs. This triggers your immune system, and trolling macrophages engulf the bacteria. While engulfing the bacteria through phagocytosis is one method (of many) your immune system uses to identify and destroy invaders, many infectious agents have learned to exploit this mechanism. Once in the macrophage, the bacterium will multiply, causing tons of bacterial cells to explode out of the macrophage and continue spreading the infection throughout your tissues.

While your body is working to fight off the rapidly replicating Legionella bacteria, you'll start to experience symptoms, such as fever, chills, and a cough. Depending on the severity of your infection, you can cough up blood, sputum, or a combination of the two. Chest pains are common, and some people can also experience diarrhea and vomiting. A combination of chest x-rays and bacterial culturing will land you with a diagnosis of Legionnaires' Disease. Since this is mostly rare form of pneumonia, it is incredibly important to get an accurate diagnosis. Since Legionnaires' Disease is caused by a bacterial infection, there are specific antibiotics that can be used to treat your infection. As always, when left untreated, the disease will get significantly worse, and may be fatal. Pneumonia is a significant cause of death for those who have compromised immune systems, and for children without access to medical care.

So, San Quentin Prison has shut off their water supply (with the exclusion of toilets, that have now been deemed okay), but this still raises the question of how extensive the contamination is. If only one person was affected, it may have been an isolated incident from an isolated source. Yet, with 30 potential patients, this is a larger issue that most likely stems from the prison's water source.

Sunday, July 19, 2015

Gendered STEM Stereotypes

Cartoon credit: Laura Grover via Public Radio International

I saw this on my facebook feed the other day, and at first I thought, "oh, just another cartoon about gender gaps and recruiting women and girls into STEM fields..."

But, then I realized that a) my disenchanted reaction is a result from the overwhelming amount of media attention that has been dedicated to the subject of women in science lately (always?), and b) this cartoon pissed me off. In the 5+ years that I've been running this blog, I've maybe covered 3 political topics because that's not my main goal. There are enough blogs out there that overlap personal opinions and science or STEM (science, technology, engineering, and math) topics, and really, who cares? But I'm going to talk about the issues of gender in science today, because there are some issues that aren't being discussed by most popular news and media outlets.

Let's address each of my reactions separately, shall we?

a) My disenchanted reaction due to the overwhelming amount of media attention that has been dedicated to women in science:
Everyone is eager to tell you that women are underrepresented in STEM fields. In a lot of places, women are still treated as diversity hires. There are societies for women in science, scholarships given to encourage young women to major in STEM degrees, organizations to help young girls find the path to STEM careers, and Google doodles dedicated to Marie Curie.


I think people love to believe that women are minorities in STEM because everyone hates statistics. I know, I am not a fan of statistics (exception: when you work super hard on some statistical analysis and get really satisfying results), but I can break some recent statistics down for everyone:

According to this economic briefing released in October of 2014 by the Council of Economic Advisers to the President of the United States, women are "now more likely than men to earn a bachelors degree and attend graduate school".

In fact, women 25-34 years old were 21% more likely to graduate from college than men, and 48% more likely to attend graduate school.

Image credit: US News
Speaking of minority populations, I'm happy to report that this trend of women being more likely to attend college and graduate with an undergraduate degree has been shown across Hispanic, Black, Asian, and Caucasian populations.

Statistics associated with women obtaining degrees in STEM fields are EVEN BETTER, according to an NSF study released this year. According to the report:
 "Women have earned 57% of all bachelor's degrees and about half of all science and engineering (S&E) bachelor's degrees since the late 1990s. However, women's level of participation in S&E fields varies, and within fields it tends to be consistent over every degree level. In most fields, the proportion of degrees awarded to women has risen since 1993. The proportion of women is lowest in engineering, computer sciences, and physics. Women earn about one-third of the doctorates in economics and slightly more than one-fourth of doctorates in mathematics and statistics."
 I'm curious, would you have guessed that women earn approximately half of the science and engineering undegraduate degrees conferred in the US?

My point is HELLO WE ARE HERE. WE ARE DOING SCIENCE RIGHT NOW. Women are represented in STEM fields. We are in the lab, in the field, in the workshop, in space, published in leading scientific journals, on computers, on advisory boards, at conferences, and in classrooms and lecture halls. Quite frankly, every time an article comes out about the need to recruit women into STEM, a young girl gets discouraged and decides that science hates women.

Ella Tyree, image credit: cliotropic

Also, every time an article comes out about the need to recruit women into STEM careers, someone of an actually underrepresented population in STEM fields loses hope. Example:
Despite considerable progress over the past two decades, the gap in educational attainment separating underrepresented minorities from whites and Asians remains wide. In general, underrepresented minorities are less likely than whites and Asians to graduate from high school, enroll in college, and earn a college degree. Among underrepresented minorities who do graduate from college, the overall degree patterns are similar to those of whites. Asians are more likely than whites and underrepresented minorities to earn a college degree in a science and engineering (S&E) field. Although whites' share of S&E degrees has declined over the past 2 decades, they continue to earn a majority of degrees in all broad S&E fields.
This example is from the same NSF survey cited above. When I worked for NASA, I worked in a building that was full of white men and women. There were a ton of women (in fact, our lab was 75% women!), but I can't say that I ever interacted with any Black or Hispanic researchers, primary investigators, or division chiefs. When I started working at Stanford, I went weeks until I saw a black person on campus -- not just my building, but on the entire campus. I have other examples, but they all seem redundant. I attended a college where Black students were the majority, yet the halls of the science buildings were mostly white.

If you really want to continue talking about women in science, maybe our attention should be diverted from recruiting and instead, focus on fixing the anti-women culture that surrounds STEM fields. Actually, we shouldn't be recruiting women into fields where a majority of them feel they need to leave because they are repeatedly sexually harassed or verbally discredited. Its not sustainable, and its not safe. We shouldn't have to laugh at things like the #distractinglysexy hashtag. We should laugh because we can laugh at ourselves, not because its an uncomfortable situation that no one really wants to talk about.


b) The above cartoon pissed me off.
When I was a young girl, I played with barbies and cabbage patch dolls. I acted out my ridiculous dreams by "playing Ninja Turtles" with my best friend, a young boy that lived across the street. I was a gymnast and I loved birds. I built furniture while listening to AC/DC with my dad. My favorite color was purple, not pink. As a teen, I found punk rock and would go into mosh pits. I wore men's pants one day and a mini skirt the next. I played water polo on a co-ed team and drew anatomically-correct cadavers in art class. I loved math until I hated it. I helped one of my high school boyfriends work on his '72 chevelle malibu and drove it more than he did. I shaved my legs and armpits, or I didn't. I dyed my hair every color imaginable. I dressed like a pin-up girl sometimes, and other times I'd be mistaken for a man (well, a young man).

I wasn't a stereotypical girl, but to be honest, I don't know many women who ever followed a stereotypical path. Maybe that's because the roles and actions expected of women have changed rapidly with each decade, thanks to our ever growing ability to collectively stand up for the things we don't like. But, really, what does feminine mean anymore? Does it mean pink? Does it mean being a mom? Does it mean working, not working? Does it mean wearing skirts and high heels all the time? Does it mean feeling bad about yourself and your body, or living by the rules of magazines like Cosmopolitan,  or any other magazine that's actually owned and funded by a group of men?

I'm going to have to say I don't actually know, but I do know that my heart didn't always lead me to science. I found it eventually, but I wasn't actively recruited. Science found me. I think that's what really makes me mad about cartoon above, actually. I did like dolls (and no, I never ripped the heads off of any of my barbies), and I also liked to do fun things. I liked to do things that made me feel smart, and challenged what I understood about the world. Science is about exploration, and when you are young, so is playing with dolls! I like science because its gross and beautiful at the same time, which is oddly how being a women makes me feel most of the time. 

The cartoon really makes me mad because I don't see the point in trying to emphasize gender in science. It's an issue if you are harboring an unsafe culture full of harassment, but it shouldn't be an issue when recruiting kids into science. We're hearing about more kids deciding to transition between genders, and who is to say what they'll be interested in doing as adults? No one, because its 2015 and your gender shouldn't define what you can and cannot do.


If we educate girls and boys and everyone in between on an equal level, then people will find their own path. We shouldn't be forcing science, but showing everyone why it is awesome and for everyone. Saying women who aren't stereotypically feminine are better suited for careers in STEM is like saying you have to be quirky, rude, and somewhere "on the spectrum" to be a scientist (like the Big Bang Theory leads many people to believe). Also, can we please talk about other women in science instead of only praising Marie Curie all the time? Yes, she was great, but other women in STEM were/are great too.

I currently work in a lab with two other women. Both of them wear lipstick and dresses all the time. I don't ever, unless its required of me. One of them loves the color pink so much that I ordered her a hot pink ice bucket and tube racks for the lab. She also has a PhD. We both bleach our hair. At NASA, our analytical chemist was (is still) a mom, a runner, and someone who volunteers with her church every weekend. Another chemist at NASA, a researcher with her PhD, looked like a Puerto Rican version of Taylor Swift and ruled everything just the same. Just because I have tattoos, and choose to wear jeans and no makeup every day doesn't mean I'm more or less qualified to be a scientist than any of these other women, or any of the men in STEM fields either.

We all attack our lives differently, and our interests or career choices shouldn't have anything to do with the gender we prefer for ourselves. What should matter is what you bring to the table, or the lab, or the field, or the operating room, or wherever it is that you want to work. Science isn't (always) about putting things in boxes, it's about discovering what makes things unique.

and that's all I have to say about that.

Tuesday, July 7, 2015

Cat! Scratch! Fever! bowwnownow wowww

Sunset and moon over the Atacama desert (photo by me)

I apologize for missing my June update, but I was traveling through Chile. I have to admit, I didn't know that much about Chile before going there. The famous government coup occurred before I was born, and wasn't "resolved" until I was 4. High school history classes in the US don't really pay any attention to Chile whatsoever.

Lincanbur volcano (left) and desert vegitation (photo by me)


My itinerary centered around the northern regions of Chile, specifically the Atacama desert. The Atacama desert is the driest desert in the world, and is known for its abundance of copper and lapiz lazuli, a rare blue stone that you can really only get in Chile and Afghanistan. The Atacama desert is also a great place for meteorites, because the super dry atmosphere preserves them in their natural "space-state" (scientific term), and the flat neutrally-colored desert make them easy to find.

Valle de la Muerte (photo by me)

Disease-wise, Chile's had pretty excellent luck compared to its neighbors of the South American continent. Of course, after booking my flights, the first thing I did was hit the books (err..internet) to look for diseases in Chile. Its winter there right now, so mosquitoes and other disease-spreading insects aren't really an issue until the warm months return. Actually, the Atacama desert environment isn't all that great for mosquitoes, since it's dry and at a higher altitude than they generally enjoy. Sandflies, on the other hand, are the perfect candidates to spread certain infections.

Lutzomyia genus Sandfly, responsible for transmitting Bartonellosis and Leishmaniasis.

Bartonellosis is an disease caused by Bartonella baciliformis, and has many manifestations. Oroya Fever, also known as Carrión's disease, is mainly found in Peru, Ecuador and Columbia, but with vector migration, movement and spread of the disease is possible. Some travel books about Chile have warnings about Bartonellosis when traveling to the north.

Oroya Fever occurs when B. baciliformis infects endothelial cells and red blood cells. Acute phase (Carrión's disease) occurs when the infection persists in the bloodstream, causing sustained fever, malaise, hepatomegaly, jaundice, lymphadenopathy, splenomegaly, and severe hemolytic anemia. Fatality rates are high, up to 40% of patients, when acute phase infections go untreated. Risks of fatality increases dramatically by the presence of opportunistic infections, specifically by Salmonella species, as a result of transient immunosuppression.

Chronic phase, or "Verruga Peruana" or "Peruvian Warts", is an eruptive phase that occurs when endothelial cells are involved.  In addition to fever, malaise, arthralgias (joint pain), myalgias (muscle pain), lymphadeopathy (lymph node involvement), hepatomegaly (enlarged liver), and splenomegaly (enlarged spleen), patients develop a cutaneus rash produced by a proliferation of endothelial cells.The cutaneous rash involves raised lesions that can rupture and bleed.

 
Illustration of verruga peruana from 1926, via Sci ELO Peru

Verruga peruana on a child

Cat Scratch Disease, also known as "Cat Scratch Fever", on the other hand, occurs worldwide, and is caused by Bartonella henselae. I couldn't help thinking of Ted Nugent while writing this post. I like to think this song is about Bartonellosis.

Cat Scratch Disease is usually spread by fleas and ticks. Cats, being the scrappy beings that they are, can develop an immunity after being exposed at a young age. Dogs present severe symptoms. Humans are susceptible to Cat Scratch Disease infection if they are scratched by an infected cat or bitten by a flea or tick carrying B. henselae. Antibiotics can successful treat Bartonellosis.

Image "borrowed" from Galaxy Diagnostics Webinars



While I was in Chile, I discovered the abundance of stray animals that inhabit every city. It was really shocking and sad, especially to see so many stray dogs in urban cities. Santiago and San Pedro de Atacama had primarily stray dogs, while Valparaiso had some stray dogs and a TON of stray cats (that could have been outdoor pets without collars...but...). This article from last year claims there are initiatives for mass sterilization of stray dogs to help stop the growth of homeless dog populations in Santiago, but there weren't any signs of progress when I visited last week.

That's all I have for you today. Check back in a few weeks for a new update (I'm going to do two for July since I skimped out on my blogging responsibilities in lieu of vacation!).

Valle de la Luna (photo by me)


Saturday, May 16, 2015

Sentenced to Death by Spores

One of the things I find most irritating about social media is that a lot of people post articles that they either didn't read before linking to them, or when you see them in person, they can't have a follow up conversation about the subject matter. If we aren't exploiting the hyperaccessibility of information with which the internet has graced us, then what's the point? (Don't get me wrong, I love videos of cute animals, too.)

The hot topic this week that was really reminiscent of this personal irritation of mine was the sentencing of Dzhokhar Tsarnaev for his role in bombing the 2013 Boston Marathon finish line. Tsarnaev, only 21, was given the death penalty.

As you can imagine, the internet started to stir with articles about the history of the death penalty in the U.S., and infographics about how the U.S. is the only developed country that still uses the death penalty. I'll admit, the people I associate with tend to lean towards a specific side on the political scale, so I didn't really see anyone posting relief or word art of "JUSTICE" in red, white, and blue. I didn't really go looking for it either.

I couldn't find any word art, but this is clearly the next best thing. Thank you, internet.

I did see a lot of people posting about the broader concept of execution, whether or not it is moral, or representative of justice. Obviously an age-old issue that I'm not really going to discuss in this blog. But, I will ask: if you post these articles, is that enough? I mean, especially for an issue like this, where someone's life is at stake. Is it ok to say you are pro-choice, but to never donate to a clinic that provides full-scale reproductive health services? Are you standing up for what you believe in if you say you love children and want them all to be happy and healthy, but refuse to vaccinate your own child?

Image courtesy of The New Yorker
I'll admit, standing up for the rights of incarcerated people can be a tricky subject, especially if you don't live near a prison (there are a lot of them, but they tend to usually be in the middle of nowhere), or if you have no knowledge of the legal issues involved. Our society is very quiet when it comes to talking about prisoners, regardless of their sentencing current. But so many of these issues that communities are so polarized about have to do with life versus death.

Photo courtesy of Afro Punk and their coverage of the #ManifestJustice exhibit.
The prison system is a weird in-between. Are you really still living life in prison? Even if you are sentenced to death, you usually aren't executed the very next day, either. I know, you're probably thinking "why is she writing about this? what does this have to do with disease at all?"

The answer to that is EVERYTHING. Most people don't think about how diseases spread rapidly through the prison system, just like they do with agricultural livestock and in refugee camps. Any environment with a lot of living beings in small, enclosed spaces is a hotbed for communicable diseases. Also, many prisons have inadequate health care and clinics to properly serve all of the inmates accordingly.

There's one infectious disease that specifically targets incarcerated people that hasn't received enough attention as it should (I wonder why...): Coccidioidomycosis.

Coccidioidomycosis, or "Valley Fever", is a fungal infection that is really tricky to diagnose, and is often fatal because of that fact. Coccidioides immitis, the causative agent for Coccidioidomycosis, is a soil fungus that loves warm, dry climates because it's spores can be carried far distances by the wind. It's usually found in the southwestern U.S., Mexico, and some parts of South America.

C. immitis spores are carried from dry soil patches, through the air and dust, making it really easy to inhale. Most people inhale these spores and never have any complications or present any symptoms. This is most likely because they were exposed to small amounts of spores that weren't successful at mounting an infection, but it was enough exposure for their immune systems to recognize the treat and prepare a response for future exposures. Some people may also have genes that influence their resistance to Coccidioidomycosis.

Spherules of C. immitis, courtesy of University of Utah School of Medicine.

But some people aren't as lucky. People who have compromised immune systems (HIV/AIDS, autoimmune disease, organ recipients, etc.), people with diabetes, and people who are Black or Filipino are at higher risk for successful infection with complications. Children are at risk, too.

Pulmonary Cavitary Lesions caused by chronic C. immitis infection. Image courtesy of  University of Pittsburgh Department of Pathology.
Symptoms are almost always non-specific, including fatigue, cough, fever, headaches, night sweats, shortness of breath, muscle and joint pain, and rash. Yet, 5-10% of people have severe symptoms, wherein the develop long term respiratory problems due to high fungalemia (which means there's a ton of fungus in your lungs). Approximately 1% of Coccidioidomycosis cases spread to other organ systems, including the central nervous system. This can cause seizures, coma, or death.

Treatment for Coccidioidomycosis involves antifungal medication and symptom-specific management to help ease the illness and stop the spread to other organ systems. As always, treatment depends on how severe the infection is, and what organ systems it is affecting. 

There is a huge problem with inmates getting Coccidioidomysis and not getting proper treatment. Many lawsuits have been filed against the California prison system specifically, because many inmates in the 18+ prisons in the Bakersfield area have contracted Coccidioidomysis, many of which were misdiagnosed or not given proper treatment. California has even dedicated funding to routine inmate screening for Valley Fever.

The dedicated funds for screening came as a result of the lawsuits and the inmates' families advocating for better care. When I say advocating, I'm referring to writing letters to their elected government officials, working with prison system administrators, and encouraging doctors and wardens to listen to the inmates that they care for as a part of their jobs (that are paid for with state taxes)... not posting about it on facebook, per say.

If you want to read a long, drawn out story about Valley Fever, the New York Times published one about a year and a half ago. They even hyphenate "Valley Fever", which is cute?

If you think about a lot of the controversial issues we are constantly arguing about in the U.S., they can all be linked to health and disease in some way. Access to adequate housing reduces the spread of seasonal infections, some parasitic infections, and bacterial infections. Access to proper sanitation reduces the spread of countless infections. Access to education can help limit the spread of all diseases, because sometimes we aren't aware of the risks we are subjecting ourselves to, or ones that may be avoided with some extra steps (hand washing, condom usage, etc.). Access to reproductive rights can help people detect infections or other diseases and get the treatment they need. These are only a few.

What issues are you passionate about?

Sunday, April 19, 2015

Get the Rift of it

Last Friday, I was showing some of the work I've done to my fellow Stanford School of Medicine Pediatrics Department-ites, and no one had heard of the virus I've been working with lately, so I decided to turn it into a blog post!

Heyyyyyy.
Since I've only been with my lab for a short time, I started working on a project that wouldn't take a lot of time to complete (you know, to prove myself to my lab -- "look, I've already finished a project!", ha!) before sinking my metaphorical teeth into some more substantial work. Luckily, it's turned into something I can present and publish.

So, let's talk about Rift Valley Fever!

The Great Rift Valley is a massive crack in the earth's crust (a.k.a. - "rift") that basically splits Kenya in two, from north to south. Rumor has it that the Great Rift Valley was discovered by a woman, but no one believed her.

In 1910, Kenya's Rift Valley region started seeing cases of pregnant livestock spontaneously aborting their offspring. This disease was the start of a long history with Rift Valley Fever Virus (RVFV), a Phlebovirus of the Bunyaviridae family. RVFV was eventually identified as a zoonotic agent, infecting people with contact with infected livestock. Mosquitoes were eventually identified as the vector for RVFV when incidence spiked after rainy seasons, as flooding increases potential breeding areas for mosquitoes.

Cows in Kenya - photo from Wildlife Direct
RVFV infections has been restricted to the African continent, primarily in western Africa, with a small outbreak reported in Egypt in 1977. In 2000, an RVFV outbreak was reported in Saudi Arabia and Yemen. The spread is usually a result of trading infected livestock and/or climate conditions that support the migration of mosquito populations.


RVFV is an enveloped, single-stranded RNA virus. The RVFV genome is divided into 3 segments of differing sizes (small, medium, and large), all of which are circularized. Host cells targeted during infection include macrophages, hepatocytes, and endothelial cells.

A computer modeled 3D structure of RVFV - image from Dr. Juha Huiskonen
Pathophysiology of RVFV in humans includes the standard headache, high fever, weakness, back pain, fatigue, and dizziness. Most people with these flu-like symptoms recover in about a week, and that's it. In severe cases, though, patients can develop encephalitis, retinitis, and hemorrhagic fever.

Given the severe affects on livestock reproductive viability, RVFV outbreaks can have devastating affects on the economy. Not only can you lose a large amount of your livestock population through death of the infected animal, and future generations by abortion, but once infected animals are identified, you are banned from trading livestock for an extended period of time. This process has been very effective in containing RVFV to the continent, but not all infected animals present symptoms prior to trade or breeding. With a large enough outbreak, severe economic collapse could follow.
An unfortunate casualty - Image from The Travel Doctor
There is a vaccine available to herders, but it can also cause the vaccinated animal to spontaneously abort developing offspring, although at a lower rate. Yet, it's difficult to convince herders to vaccinate their animals if they are (maybe) damned if they do and (likely) damned if they don't. There are also models that have successfully predicted RVFV outbreaks in the past.

The United States Department of Agriculture (USDA) has listed RVFV as a major threat to the U.S. because of the large economic dependency we have on livestock. Even though the virus has only started to leave Africa, the U.S. does have the vectors to support spread to North America.

Saturday, March 21, 2015

Taenia solium and the leaky brain cyst

For my other blog (warning: not a scientific blog), I wrote a little thing about why Spring is one of my favorite seasons (I mean, second to Autumn of course!) because it brings an abundance of cute baby animals to the world. One of my absolute favorites is the pig! Domesticated, wild, big, small, it doesn't matter.

Image from Daily Mail.
So, in honor of all the piglets being born this season, let's talk about a classic parasite with some new research twists. Taenia solium is a type of tapeworm that is specifically linked to pigs. T. solium is related to the "beef tapeworm of man" (Taenia saginatum, tapeworm associated with cows), but can cause some much more severe symptoms.

T. saginatum scolex imaged using electron microscopy. Image taken from the internet.
T. saginatum, the beef worm, is what everyone thinks of when they think "tapeworm": adult worms have a head, neck, and proglottids, and causes intestinal obstruction and discomfort. Oh, and it can live inside of you for up to 25 years!

In order to get your own tapeworm infection, all you have to do is consume poorly cooked beef which contains T. saginatum eggs. When the eggs "hatch", oncospheres (infective larva) migrate to the small intestine, where they will take 3 months to mature into an adult worm. Adult worms are typically 2 to 10 meters in length. Usually only one worm is found, unless you've consumed a heavily contaminated piece of meat or ate fecal matter that's full of gravid proglottids (the end pieces of the tapeworm). Fun fact: eggs can survive for months once they've left the body. Beware of old poop!

Taeniasis life cycle for T. saginatum and T. solium, via the CDC

Patients infected with a beef tapeworm (clinically described as "Taeniasis") may complain of non-specific abdominal symptoms, such as nausea, general pain and discomfort, or weight fluctuations. I say weight fluctuations because most people experience extreme weight loss (often misdiagnosed as anorexia), especially those affected in developing countries (where these parasites are most prevalent), but there have been a number of people who have infected themselves, by choice, and have reported it being "no big deal" or that they gained weight (see my favorite example: Michael Mosley of the BBC News). So, while most people experience weight loss, I suppose you could say that depends on your socioeconomic status, and whether or not you've had a choice to become infected.

T. solium life cycle from the Food and Agriculture Organization of the United Nations (fao.org)
T. solium can also cause all the same intestinal symptoms, and can live out a life cycle similar to that of T. saginatum. But, in some cases, T. solium can cause something called Neurocysticercosis (cue scary music). T. solium's life cycle and pathophysiology usually looks very similar to that of T. saginatum, only with smaller worms (4-7 meters in length). Neurocysticercosis occurs when you've ingested the eggs directly, such as ingesting contaminated feces. This happens to pigs when their food is contaminated with human feces (pretty ironic, right?).

T. solium scolex. Image from UNAM.
The consumed eggs hatch in the small intestines and the oncospheres are released. Oncospheres penetrate the intestinal mucosa and make their way to the blood. Once in the blood, they travel throughout the body and migrate to different tissues, where they will mature into cysticeri. The cysticeri really like skeletal and cardiac muscle, subcutaneous tissue, and lungs, but they can also get lodged in the central nervous system (CNS), including the brain and the cerebral ventricles. Once the cysticeri have chosen a tissue which to lodge themselves, they become calcified granulomas.


T. solium adhering to the epithelial cells of the intestine. Image from UNAM.
The most common location for cysticercosis to occur is the cerebral hemispheres, at the gray-white matter junction, but they can also be found in the cerebellum, the brainstem, the subarachnoid space, the basal cisterns, and the spine.

T. solium cysts in a human brain. Image from Discover Magazine.
 Obviously, having a 1-2 cm cyst calcifying in your brain will cause some damage. Neurocysticercosis is one of the leading causes of epilepsy in developing countries. It can also cause severe headaches, hydrocephaly and eosinophilic meningitis.

The National Institute of Allergy and Infectious Disease (NIAID) just released an article about the treatment-induced inflammatory response in pigs with neurocysticercosis. The current treatment of Praziquantel is apparently causing inflammation, blood vessel leakage, and damage to the blood-brain barrier. This means that new drugs need to be developed that can reduce inflammation at the site of the cyst(s) while maintaining the integrity and functionality of the blood-brain barrier and blood vessels.

Photo of the surface of the brain of a pig treated with the antiparasitic drug praziquantel showing blue-dyed (blue arrows) and clear (white arrows) cysts. The blue dye indicates disruptions in the blood-brain barrier. Image from NIAID/
Dr. Cristina Guerra-Giraldez.
This research only focuses on pig subjects, and has not yet been performed on humans infected with neurocysticercosis.


Want to avoid tapeworms and neurocysticercosis? The best way to do that is either to avoid eating meat, or to make sure your meat is cooked properly. Cooking meat properly is the best way to inactivate or kill most infectious diseases associated with meat consumption.

One of the major reasons diseases are so rampant in livestock is because a lot of treatments (mainly antibiotics) are used as prophylactics instead of at the onset of infection and symptom presentation. Animals that are raised in small, confined areas are more likely to be exposed to illnesses. When you are raising animals on a large scale and rely on them for income (whether through livestock trade, meat or dairy production), it can be really scary when one of your animals gets an infection, because you risk losing some of your income. It's obviously unethical to sell/trade sick animals, but it happens all the time, and is one of the main causes for the spread of disease to other regions. When prophylactic treatments are used, resistant infections are more likely to occur, which is an even larger problem (as I'm sure you can imagine).

Even if the meat you consume came from a healthy cow/pig/lamb/goat/chicken/turkey/etc., it might have been slaughtered in the same environment as a sick animal, which still puts you at risk. So, if you have a tendency to order your meat "rare", be sure you know the risks associated with that choice.

Edited to add:
I want to be clear that, even though I'm vegan, I believe choosing to be vegan is a very personal choice and no one should ever be bullied in to it. But, I also feel the need to add some information about the environmental impacts of eating meat to this post, since we are talking about risks associated with consuming meat. Considering the risks to yourself is very important, so you can actively minimize your risk of getting an infection or other serious health disparity (mostly through the long-term, excessive meat consumption),  but considering the long-term risks for the environment (ie- everyone on earth) is also really important. Here are some articles that you might want to consider reading before making a definitive decision about your dietary habits:

The Triple Whopper Environmental Impact of Global Meat Production: TIME

How does meat in the diet take an environmental toll?: Scientific American

Giving up beef will reduce carbon footprint more than cars, says expert: The Guardian

2500 gallons all wet?: EarthSave


Saturday, February 28, 2015

Toxoplasmosis

I was inspired to write this entry because I have a number of friends who have recently crossed over into that place in your life where you suddenly want tons of kids. Some of them have just recently birthed their first child (congrats to you), and some are just starting to feel that warm glow of constant nausea that will stick with them for the next few months. This is an awkward time for me, personally, because I fall into the category of "never, no, not interested" when it comes to babies. I've always kind of been that way, and yes, I fully acknowledge that my feelings could change in the future. I also want to point out that it would be fine if my feelings didn't change, because it's not an obligation that all women have (to have children, that is). I should also say that I like kids, and I think that they are amazing little creatures.

I wanted to bring this up for two reasons:
1. being pregnant has to do with the parasite I'm going to discuss later in this post, and
2. the Washington Post published an article about Eugenie Clark, who just passed away on Wednesday. The article is a great little summary of her life, but this is one of the most important parts (in my opinion):
"Professors at Columbia University told her it would be a waste of their time to admit her to their graduate program because she’d end up as a housewife..."
 Granted, this was in the 50s, but it struck me to see that so boldly stated. I've had mentors make comments like that to me within the last FIVE YEARS. While it's really important to state that women like Eugenie Clark have paved the way for women scientists, we still have a lot of work to do. I've had a lot of really incredible mentors, but it's hard to move past comments that one or two bad apples may have made, especially in such early and exploratory years of my career. If we strip away all the statistics about women and minority populations in science/STEM, we can still come to the same conclusion about comments that assumingly discourage someone from doing what they want to do with their lives: it's mean. It's really mean to do that to another human being, no matter what population they do or do not fit into.

I know that was more into my personal life that I usually divulge, but that article really inspired me.

So, back to my friends and their pregnancies!
A majority of my friends that are getting pregnant/having babies also have cats. I know, I know, you know where I'm going with this because its old news and everyone should already know about it. Well, not everyone does.

Toxoplasma gondii. Image from National Geographic.

Toxoplasma gondii is a parasite that can infect all warm-blooded animals and birds (as intermediate hosts), but is primarily centered around the definitive host: cats. Actually, over 200 mammalian species can act as an intermediate host for T. gondii, which makes the prevalence in humans pretty high.

As you can see below in this terrifyingly hilarious life cycle image (thanks, internet), the life cycle of T. gondii (sexual development) is completed in the intestines of a cat (even if it is a cross-eyed Halloween caricature of a cat like the one in this image).

Image discovered somewhere online, although I couldn't find a clear source which to give credit. Sorry.
Infection in humans is usually asymptomatic, meaning a non-infective (dormant, non-pathogenic) stage of T. gondii could be in you right now, and for most of your life without you even knowing! Most infections are triggered by a state of immunodeficiency. There have been some studies that have looked at the possible correlation between T. gondii infection and schizophrenia (a few years ago, you may have seen a bunch of sarcastic articles about how your cat is trying to control your mind, etc.). If you do develop acute Toxoplasmosis, you'll usually only experience non-specific symptoms, such as malaise, fever, and other flu-like symptoms that can resolve themselves within a few weeks or months. A lot of times, Toxoplasmosis isn't diagnosed correctly because proper diagnosis is really dependent on the organ system that is infected (heart, eyes, brain, etc.), and depends on the pathology lab to identify the organism in your tissue samples.

The biggest issue with Toxoplasmosis comes when you are pregnant, because it can cause spontaneous abortion, or if you carry to term, can be passed congenitally causing hydrocephaly, mental retardation, cerebral calcification, and chorioretinitis.

If you are pregnant and have an indoor/outdoor cat that uses a litter box in your house, I'd suggest avoiding any contact with it for the time being. You can be exposed to infectious fecal particles while emptying the litter box, that can be ingested accidentally. I'm not really sure why you wouldn't wash your hands thoroughly after handling an animals wastes, but that might be another thing you'd want to start doing, especially now that you are pregnant and all.

 Another fun thing about T. gondii is that you can become infected through organ transplantation! Organ recipients can get Toxoplasmosis from the new organ, or from self-activation (if you've already been infected with a dormant, non-pathogenic stage, but go into immunodeficiency after surgery). This is pretty rare, but it is possible.


Here's a picture of my cat, Milo (aka "Beef"), who usually helps me write these blog posts, and made it known that she does not appreciate this particular entry.