5 Diseases That Will Keep You Out Of The Water This Spring Break

Ah, Spring Break is finally upon us...a great time for rafting, surfing, swimming, and rehydrating. Before partaking in all these fun activities, we should remind ourselves about the sinister creatures lurking in waters all around the world just waiting to take us down. These aqueous villains don’t have big teeth and a menacing theme song to make you hydrophobic, but learning about these tiny critters might make you think twice about jumping into the next hot spring you see.

1. Primary amebic meningoencephalitis

Primary amebic meningoencephalitis (or PAM as it is known by those acronym-loving physicians) is caused by an amoeba called Naegleria fowleri. But aren’t amoebas those cute little single-celled organisms that we’ve all spied on through middle school microscopes and laughed at in Far Side comics? Nothing scary there.

This is why Naegleria fowleri should always be referred to as brain-eating amoeba. Yes, BRAIN EATING, as in plowing through your cerebellum like Homer Simpson gorging on a jelly donut. It is the real-life zombie of the parasite world, possessing an insatiable appetite for grey matter.

There’s only one thing the brain-eating amoeba enjoys besides neuronal soup: warm weather. This mind melting nemesis is largely found in still waters in the southern US, but global warming is allowing it to creep up to areas further north. Just one good snort of contaminated water sends this hungry little amoeba to the brain buffet.

This amoeboid parasite is a glutton, and that is its undoing. A smart parasite, like Toxoplasma gondii, goes to sleep in the brain so it won’t kill its host. But Naegleria fowleri goes on a brain devouring binge with no thought to sustainability and literally eats its host to death.

Naegleria fowleri is rather prevalent, but human infection is very rare. The bad news for those who are susceptible is that there is no cure. You will be host to this unwelcome guest for about six days before there isn’t enough brain to support the two of you any longer. So if you can’t resist the urge to go skinny dipping, at least wear some nose plugs.

2. Cryptosporidiosis

Who remembers that childhood classic sung in elementary schools around the world, “When you think your friends are joking, but your pants are brown and soaking…diarrhea, diarrhea!”

If parasites had theme songs, Cryptosporidium would surely claim “The Diarrhea Song”. Sure, Giardia and some other gut pathogens might complain since they are excellent poo liquefiers too, but they’ve never sent an entire city running for the bathrooms at the same time.

In 1993, the single-celled parasite Cryptosporidium brought gastrointestinal misery to over 400,000 people in Milwaukee, overwhelming city hospitals and even killing at least 100 of these unlucky souls. The parasite is a common pathogen in cattle and somehow found its way into the city water supply (in other words, people were drinking water that had cow patties in it).

The Cryptosporidium cysts expelled by infected cattle (or infected people) are very tough, even resistant to chlorine. People can become infected from contaminated water in lakes, pools, or water fountains, or by taking care of infected babies or patients. Once ingested, the cysts break open and the parasites inside invade your intestinal epithelial cells. They steal nutrients from your cells in order to replicate and make more cysts that get back out into the environment after turning your insides into their ultimate water slide.

Cryptosporidium is the microbial equivalent of Turbo-Lax. With no vaccine or effective treatment available, patients just have to stay hydrated, hunker down with plenty of aloe-infused TP, and wait out the unpleasant infection, which can last up to two very long weeks.

3. Cerebral sparganosis

“The magnetic resonance revealed widespread white matter degeneration and cortical atrophy”. If you hear a doctor say that, then there’s a good chance you have a flatworm called Spirometra mansoni in your brain that causes cerebral sparganosis. In everyday language, this means your brain has turned to Swiss cheese.

To be fair, Spirometra mansoni has no desire to infect you, as humans are not the definitive host. It would much rather be left in the water to invade tiny crustaceans, which are then eaten by a second intermediate host (fish, amphibian, or reptile), with the ultimate dream of getting into a dog or cat. But no, you had to take a gulp of water and disrupt this parasite’s travel plans. Since it can’t use you to make eggs and get its offspring back into the environment, the pissed off tapeworm wanders around your body and, in some cases, makes its way to the control center to vent its sexual frustration.

So how do you get these nasty things out of your head? Well, you should probably let a surgeon do it, no matter how good your friend claims to be at that Operation game. Your surgeon will likely use a technique called stereotactic aspiration, which is an innocuous way of saying, “poke a hole in your head and suck the larvae out”.

4. Candiru

Our next water dwelling devil is called candiru and it is the star of every man’s nightmare. Candiru is also known as the vampire fish, which is an awesome nickname, but what this toothpick-shaped catfish is purported to do is not cool, bro. Not cool at all. Any guesses?

The slender shape of candiru has gracefully evolved to fit in-between the gills of other fish, where this vampire draws its blood meal. Unfortunately, it is also perfectly suited to tunnel its way into a man’s urethra. Even worse, the victim can’t simply pull the fish out because candiru projects spikes that firmly implant its body into the urethra wall. The only options for slaying this vampire include amputation or expensive surgery, so best wear a condom when swimming with the vampire fishes.

If you’re thinking that it seems quite improbable that an eel-like catfish can hit such a small target, you’re probably right. There are reports that vampire fish can follow urine streams like a yellow-brick road, but this claim was tested experimentally and proven to be a myth. The few reported cases of candiru infiltrating urethras are not without controversy, so you probably only have to fear candiru in your nightmares.

5. Mycobacteriosis

By now you probably won’t be setting foot near lakes, rivers, or even mud puddles ever again. You’ve resigned yourself to just sit at home and take your mind off these terrors by gazing into your tranquil aquarium. Ah, what danger could come of that?

Mycobacteriosis! Otherwise known as fish-handler’s disease or aquarium granuloma, mycobacteriosis is one of the unspoken hazards of maintaining an aquarium. Think about it for a minute. Fish eat. Fish pee. Fish poop. And you haven’t changed the water in three, maybe four, months! That poor fish is swimming in a cauldron of bacteria, including a variety called Mycobacteria. Some species of Mycobacteria cause such lovely diseases as tuberculosis and leprosy, but the one in fish tanks is usually Mycobacteria marinum. If you stick your hand in the water to play tag with Nemo or set up his new SpongeBob pineapple house, Mycobacteria marinum can enter your body through an open wound on your skin.

Like other Mycobacteria, the infection is very stubborn and lasts a long time even with antibiotic treatment. You may also be left with ugly scars and/or arthritis to serve as a permanent reminder that you need to change the water in your fishy friend’s tank frequently. In some cases, especially immunocompromised people, infection with Mycobacteria marinum has resulted in amputation or even death. So ditch the aquarium now and just install a fish tank screensaver on your computer desktop.

Contributed by:  Bill Sullivan
Swim with Bill on Twitter.


The original version of this article appeared on BuzzFeed Community.



Bauer IL (2013). Candiru--a little fish with bad habits: need travel health professionals worry? A review. Journal of travel medicine, 20 (2), 119-24 PMID: 23464720

Lead: Breaking Down The Bridges Of Life For Centuries

In February of 2015, after months of seeing her children randomly lose hair and complain of stomachaches and other symptoms, LeeAnne Walters finally had the water in her house tested by city officials. As she feared, the results were not good. Lead levels showed a content of 104 parts per billion, nearly 7 times the EPA limit for lead in drinking water. In April she would go on to discover that all four of her children had lead in their blood, and that her son Gavin was actually poisoned by this heavy metal.

The Walters are one of the many families in Flint, Michigan suffering the consequences of the lead poisoning epidemic that resulted from city officials switching the source of city water from Lake Huron to the Flint River. We now know that the corrosive nature of Flint River water leached the lead from aging city pipes; what started as a cost saving measure resulted in nearly tripling the percentage of Flint children having elevated lead blood levels.

Repeated exposure to lead can cause diverse symptoms including abdominal pain, headaches, memory loss, weigh loss, and anemia. Children are particularly susceptible to the ill effects of lead toxicity, which can result in developmental delays and learning disabilities among other long-term, irreversible health issues. Thus, despite the change back to Lake Huron water in October, this man-made disaster will be affecting the residents of Flint for decades to come. Thanks to recent national press attention, the events that led to this water crisis as well as its health-related consequences are well known to most.

The weight equivalent of only ~1/16^th teaspoon of salt in lead in the bloodstream of an adult sets off alarms of concern - but what is it about lead that makes it so toxic? What does lead do at the cellular and molecular level that contributes to such widespread and profound effects in the human body?

Mark Nowlin / The Seattle Times

Lead typically enters the body through either ingestion or inhalation of lead particles that contaminate water, food, or the environment. In the United States, up to 20% of the half a million children living with lead poisoning were exposed through the drinking of contaminated water. Once ingested, lead is absorbed through the gastro-intestinal (GI) system, a process that is greatly influenced by age:  while only 10% of lead ingested by adults is absorbed, up to half of that ingested by young children will be absorbed. In addition, diet and nutritional health play a role on absorption levels. Low calorie intake, vitamin, and iron deficiency, as well as a high-fat diet, have all been correlated with enhanced absorption of lead, which contributes to the higher prevalence of lead poisoning among children from economically depressed regions such as Flint, Michigan.

After absorption, lead enters the blood, where it is mostly associated with red blood cells (RBCs). One of the effects of lead is to weaken the membrane of cells leading to their rupture. In the context of RBCs, this results in a process known as hemolysis and contributes to the anemia often associated with lead poisoning. Another key effect of lead that contributes to anemia is the inhibition of enzymes responsible for making heme, a critical component of many proteins including hemoglobin. Unregulated inhibition of enzymes, like that caused by lead, generates an excess of reactive oxygen species (ROS), which in turn can disrupt nearly all components and functions of any cell. Unfortunately, not only does lead produce this so-called “oxidative stress”, but it also inhibits the antioxidant proteins and other molecules our cells would normally use to protect themselves. The net result is a perfect storm of damage and lack of protective mechanisms that spells the ultimate demise of the cell.

Interestingly, while the blood lead level is what health professionals use to monitor exposure, only a small fraction of the total lead burden in the body is found in the blood. A significant amount of lead accumulates in soft tissue organs such as liver, lungs, kidneys, and importantly the brain. Indeed, one of the primary targets of lead toxicity, especially in children, is the central nervous system. The adverse effect of lead in neurons is again a combination of ROS production and inhibition of antioxidants, plus the disruption of proteins responsible for neural functions such as the release of neurotransmitters. Nonetheless, nearly 90% of lead retained by adults and 75% of that retained by children ultimately ends up in the bones and teeth. It actually takes up to 30 years to eliminate half of the lead that enters the bone, and bone-to-blood transfer of lead, which increases during pregnancy, menopause, and aging, can serve as a source of lead toxicity long after initial exposure.

Lead’s uncanny ability to inhibit such a broad range of enzymes is due to its high affinity for sulfhydryl (sulfur and hydrogen) groups, including those attached to carbon, which are known as thiols. A biologically important thiol is the side chain of the amino acid cysteine, one of the 21 building blocks that make up proteins. Because two thiol groups can react with each other to form disulfide bonds, cysteines in different parts of a protein - or even in different proteins altogether - can bind to one another. The ability to form these disulfide bridges makes cysteine a very special amino acid that contributes to a protein’s structure, stability, function, and ability to interact with other proteins.

Disrupting and remaking disulfide bridges between proteins is the basis of chemicals used by hairdressers to straighten and curl up hair.

By strongly interacting with thiols, lead can break disulfide bridges and ruin the structure and function of enzymes, sometimes permanently. The ubiquitous presence of thiols in proteins and their importance to function is what allows lead to affect such a broad range of cells, organs, and processes. Another chemical property of lead that contributes to its toxicity is its divalency (ability to make two bonds). Once inside of cells, lead can take the place of biologically important divalent ions such as calcium and magnesium with dire consequences. Calcium, in particular, plays an important role as a signaling molecule and therefore its level inside of the cell is tightly regulated. When lead levels are high, it can activate proteins and processes, such as neurotransmitter and hormonal release, which are normally controlled by calcium fluxes.

Lead has been intrinsically interconnected with human history. Ancient civilizations considered it the father of metals and the Romans laced their wine and aqueducts with it. Soft, highly malleable, and with a low melting point, lead is in many ways an ideal material. But its more pernicious character as a poison has also been recognized for centuries. There is no known safe level of lead and its effects are widespread, long lasting, and unpredictable. While the pharmacokinetics, mechanism of toxicity, and chemical properties of lead are fascinating, they are insignificant and almost irrelevant in the context of the human cost lead poisoning has inflicted throughout history and continues to inflict. LeeAnne Walters’ son Gavin and the many other afflicted children from Flint, Michigan are unfortunately the latest to pay the price.

Contributed by:  Gustavo Arrizabalaga, Ph.D.

Follow Gustavo on Twitter.

References and resources:

http://emedicine.medscape.com/article/2060369-overview

http://www.cdc.gov/nceh/lead/

http://michiganradio.org/post/timeline-heres-how-flint-water-crisis-unfolded#stream/0

Flora G, Gupta D, & Tiwari A (2012). Toxicity of lead: A review with recent updates. Interdisciplinary toxicology, 5 (2), 47-58 PMID: 23118587