The First time I ever held a snail, my mother immediately handed me soap and disinfectant in an attempt to wash off the bilharzia from my hands. Surprised? Yeah, that’s what I thought. I know there are a lot of people out there like my mother who want to keep snails as pets but are just as scared of  Bilharzia. So, do snails cause bilharzia? 

Snails don’t cause bilharzia but they only host the parasite( Schistosomes) that causes Bilharzia. This is a parasitic worm that attaches itself to freshwater snails. Once it detaches from the snail, it stays in the water until it enters the body through contact with the skin. 

In this article, I discuss the role of snails in the transmission of Bilharzia. I also cover the other parasites that snails carry, how to tell if your snail is unwell, and how to avoid Bilharzia.

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Snails Don’t Cause Bilharzia. But, This is How They Contribute to the Transmission of Bilharzia

Science Direct and Pubmet did in-depth research in 2019, intending to uncover the deep mysteries of  Bilharzia. The research mostly covered the causes of Bilharzia and the areas where Schistosomiasis is prevalent, including the means to eradicate Bilharzia. Did you know scientists that are considering the complete eradication of snails as a preventive measure of snails? Actually, In the near future, snails might be a story of the past. 

For exquisite results, the scientists carefully analysed a total of  273,700 snails from the Bulinus and Biomphalaria. They did this in an attempt to determine the exact cause of Bilharzia, and this is what they found out; Blood flukes of the Schistosoma genus found in snails are what cause Bilharzia. Out of all the trematodes, only 5 of them affect human beings. They include;

• S. Japonicum( Source)
• S. intercalatum ( Source)
• S. Mekongi( Source)
• S. Mansoni( Source)
• S. Japonicum( Source).

These five Bilharzia parasites thrive in two hosts, that is, freshwater snails and mammals. But in this case, I will only focus on how the parasites affect human beings as mammals.

1) Snail Hosts

See, when an infected person poops or pees, they release the fluke’s eggs into the water, through their urine or faeces. It’s in the water that now these eggs become miracidia that hatch to infect the snails.

These tiny parasites will then find their way into the snail, where they develop into adult parasites. The females then begin to multiply, asexually, bringing along baby sporocysts. The baby sporocysts will now reproduce into the same baby parasites. Alternatively, they may mutate into a whole new kind of baby parasite. They more or less, create a whole generation of their own.

2)Mammalian Hosts- Human Beings

Fun fact; did you know the parasites shed their forked tails once they enter the human body?

Once the parasites come in contact with the human skin, the female worms begin to grow until they become egg-laying adults. The eggs then begin to migrate in the human body until they find their way into freshwater bodies. Again, through faeces or urine, and the cycle continues.

In an ideal situation, the trematodes’ eggs should swim through the intestines and come out with the faeces. Yet, sometimes they get trapped in other organs, like the lungs or intestinal lining. 

When this happens, infections occur leading to inflammation in the abdomen and the affected area. The belly usually grows to an immense size. The only reason the parasites infect both human beings and snails is to survive. Turns out, the parasites are not that evil after all. They are only a generation fighting to survive. Even so, Bilharzia is quite a pandemic in some countries.

You must have heard of how much Bilharzia affects developing countries, especially Africa. Right? Well, yes. The rumour is true. In one year alone, you can expect about 250 people million in Africa alone to acquire the disease, with about 780 million people still at risk of getting Bilharzia. Out of this number, 280,000 people don’t make it alive. Sad right? Yes. Bilharzia is quite a blow in Africa ( Source).

Interestingly, scientists rank Bilharzia number two after Malaria out of infections caused by parasites. Although it is prevalent in Africa and developing countries like Asia, you can still find it in other countries considering it’s a water-based illness. That is, if anyone travels to a country with Bilharzia, they can easily carry it to a country without Bilharzia. So, always make sure you take all the necessary precautions.

What Other Diseases Can Snails Carry?

Although Bilharzia is the most common and dreaded infection associated with snails, there are still other potentially dangerous infections that snails carry. The common ones are ;

• Clonorchiasis: This is a parasitic infection where the parasites dwell in the liver, infecting the bile ducts. You will find this disease widespread in China, Japan and Korea( Source).
• Angiostrongyliasis: This condition is also known as rat lungworm. I don’t know if you thought the same after reading this. But, the first time I heard the name rat lungworm, I immediately thought the parasites live in the lungs of worms. Turns out I was right. Like the name, you can expect to find the parasites in the brain and spinal cord of rodents. After which, the parasites find their way into snails after the rodents poop. Although this infection mostly affects rodents, if you eat raw meat from its host( rodents, snails or shrimps), you can get infected.
• Fasciolopsiasis: This intestinal worm found in Southeastern Asia is the greatest fluke among humans. The best way you can avoid it is by cooking sea plants and animals before cooking them( Source). 
• Paragonimiasis: This specific worm attacks the human lungs after eating raw crayfish or crab.  While it’s not a serious infection, once it gets to the nervous system then it becomes life-threatening( Source).

How Can You Determine if Your Snail Has an Infection?

You might notice parasites on the snail, changes in the snail’s shell to form cracks, decreased activity or spots on the body. All these signs can show your snail has an infection but are also signs of other scenarios.  For example, if your snail has decreased activity, it could also mean that your pet has had a long day, right? Not to disappoint you, but, even if you find a parasite on your snail, there isn’t any proven remedy to treat your snail. 

How Can You Avoid Bilharzia?

There isn’t any available vaccine for snail fever. That is why it’s critical to understand the black spots for Bilharzia and take caution to avoid them at all costs.  There is available information to check if the country you are visiting is known to have Bilharzia. That said, developing countries like Asia and Africa are the countries with the most common areas known to have Bilharzia.

If you must visit these areas, observe the following;

• Do not swim, paddle, or wash in freshwater bodies. Ensure the pools you swim in have chlorine treatment. Ocean water is also safe for swimming.
• Ensure you boil drinking water for about 5 minutes. Although parasites do not travel through food, they can still attach to your lips or your mouth 
• Avoid any unprescribed drugs said to prevent or treat Bilharzia. There isn’t any available vaccine for Bilharzia. Additionally, you need laboratory tests to confirm if you have Bilharzia.
• Do not take hotel words as the truth to certify that the water is safe for drinking. Buy water from credited sources to drink instead of tap water. 

Very important : Drying your body with a towel after a dip is not a reliable way to prevent yourself from getting an infection from contaminated water. Still, it’s wise to immediately take a good shower and then seek medical attention. 

How Do You Detect Bilharzia?

If you suspect that you’re infected with Bilharzia, you need to make an appointment with your doctor. They will take a sample of your urine and stool, or both for a lab test.

My Thoughts

Unlike what most people Believe, snails do not actually cause Bilharzia. Instead, the schistosomiasis parasite that uses both humans and snails for survival is what causes bilharzia. Thank you for your time and cheers !