Infecting snails

  1. Use a 24-well tissue culture plate if the snails are 12 mm or less. Aliquot 1 mL of pond water into each well. Do this while the liver material is spinning.
  2. Place the snails into individual wells. Mark the lids to keep track of which snail is in each well. This should be done right after you finish layering the volumetric flasks.
  3. Take a 1.0 mL aliquot and put it in a 15 mL conical tube. Remove a 10 μL aliquot of the parasites and place it on a slide. Put it in the -20°C for about 10 seconds, then remove and immediately view under the microscope to count the parasites present. Repeat twice so you get a better idea of how many parasites there are per μL. If there are too many to count, dilute the original 1 mL aliquot with pond water and repeat the counting process.
  4. You want to add 10 parasites per well, so work out the volume you need for each well — for example, if you counted 5 parasites in 10 μL, you need 20 μL per well.
  5. Add the required aliquot of parasites to individual wells containing snails. Try to squirt the parasites right onto the head-foot of the snail.
  6. Let the snails sit with the parasites for 1.5–2 hours. During that time, periodically check that the snails stay within their well and in the pond water.
  7. Afterwards, carefully remove the snails and put them in the appropriate cup in the snail room, containing pond water and lettuce.

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Wear a clean pair of gloves when you return the snails to their cups — you do not want to introduce any parasites to the colonies. Alcohol off your gloves after handling the infected snails and before entering the snail rooms.

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Maintaining schistosome-infected snails

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Avoid contact with parasite-contaminated water. Always have 70% EtOH available. Wear double gloves and a lab coat when entering the infected snail area.

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Move snails to clean cups as needed, and replenish lettuce as needed.

  1. Label the infected snail cups with important information: snail strain, date infected, snail well and plate number, and so on.
  2. Place clean cups in a plastic bin. Put as many cups as you can in the bins, even if you will not use them all — this makes the cups less likely to fall over. Fill the cups with pond water. Add lettuce, and a small piece of styrofoam if you are collecting babies. Optional: add a few pieces of washed coral.
  3. Carefully transfer the infected snails into the clean cups with forceps. If at any point you come into contact with the water, alcohol off your gloved hands. Make sure to place snails in the correct cups. If a snail has visited a different cup, separate the snails and note it in the notebook. Sometimes a snail may crawl up the side of the cup and look dried out — transfer it into its new cup anyway, as it may survive.
  4. After transferring the snails from one bin, place the forceps on paper towel and alcohol off your hands. Put the new bin on the shelf and continue with the next set of snails.
  5. When you're finished transferring all the snails, alcohol off the forceps over paper towel, wipe them, and put the paper towel in the biohazard bucket. Alcohol off your gloved hands.
  6. Place the old cups on the shelf and mark with the date.
  7. Take the cups from the previous change and dump the water into the waste bucket, which contains bleach. Spritz the cups with alcohol and let them sit overnight. After 24 hours, wash with a small amount of soap and rinse well.
  8. Alcohol off your hands after each step. Remove your gloves and lab coat if you leave the infected area, and place the gloves in the biohazard bucket. Once the bucket is full, remove the bag and autoclave it. Put in a new biohazard bag.