The parasite lives in bowel movements (stool, diarrhea) from infected people and animals.

• It spreads through water—The parasite can live in drinking water or swimming pools. People can get infected when they swallow water that has the parasite in it.
• People who have the infection can spread it if they do not wash their hands after a bowel movement/ using the bathroom. You can get sick if you touch an infected person or change an infected baby's diaper and then not washing your hands afterwards.

Based on CDC guidelines, people with severely weakened immune systems are at risk for more serious disease. Examples of people with weakened immune systems include those with HIV/AIDS; those with inherited diseases that affect the immune system; and cancer and transplant patients who are taking certain immunosuppressive drugs. These individuals may have more severe diarrhea that can persist long enough to become life-threatening.

People with weakened immune systems due to cancer, HIV, immunosuppressive drugs for transplanted organs, inherited diseases such as agammaglobulinemia, or IgA deficiency, are advised to:

• Drink bottled water
• Boil tap water for one minute before consuming
• Filter tap water using a filter labeled to ANSI/NSF 53 or 58 standards, or a filter that is labeled “absolute 1 micron.” (i.e., not Brita-type filters)

You can lower your chances of getting cryptosporidiosis if you do the following:

• Wash your hands with soap and water for at least 15 seconds before eating or handling food, and after going to the bathroom or changing diapers.
• Throw away dirty diapers and animal bowel movements in a closed garbage can away from where you cook and eat.
• At home in the impacted zone, immunocompromised persons should only eat food that is fully cooked and should thoroughly wash vegetables and fruits that are consumed raw with uncontaminated water.
• Do not drink water from streams, lakes, or public swimming pools.

Cryptosporidium levels detected in our water supply indicate a low risk for the general population. This means that for most people with healthy immune systems, the water is still safe to drink.

Losing a lot of fluids from diarrhea can be dangerous—and especially life-threatening in infants. If you are pregnant or a parent and you suspect you or your child are severely dehydrated, or if you have severe or long-lasting diarrhea, you should consult a health care provider.

People with weakened immune systems due to cancer, HIV, immunosuppressive drugs for transplanted organs, inherited diseases such as agammaglobulinemia, or IgA deficiency, are advised to:

• Drink bottled water
• Boil tap water for one minute before consuming
• Filter tap water using a filter labeled to ANSI/NSF 53 or 58 standards, or a filter that is labeled “absolute 1 micron.” (i.e., not Brita-type filters)

You can lower your chances of getting cryptosporidiosis if you do the following:

• Wash your hands with soap and water for at least 15 seconds before eating or handling food, and after going to the bathroom or changing diapers.
• Throw away dirty diapers and animal bowel movements in a closed garbage can away from where you cook and eat.
• At home in the impacted zone, immunocompromised persons should only eat food that is fully cooked and should thoroughly wash vegetables and fruits that are consumed raw with uncontaminated water.
• Do not drink water from streams, lakes, or public swimming pools.
• Cryptosporidium levels detected in our water supply indicate a low risk for the general population. This means that for most people with healthy immune systems, the water is still safe to drink.

In the event of a boil water advisory, CDC provides this guidance for hospitals, healthcare facilities, and nursing homes, this guidance for dialysis centers, and this guidance about safe water use in dialysis. If your facility is located within the affected area, you may want to consider implementing precautions for some or all of your patient population.

For immunocompromised people at risk of crypto, eating at restaurants in the impacted zone comes with some risks. However, if such individuals choose to eat out in the impacted zone, they should only eat at restaurants that are able to provide commercially produced ice, and commercially bottled water or water that’s been disinfected for Crypto by being boiled for 1 minute or distilled and cooled for consumption. Further, whether at home or at a restaurant in the impacted zone, immunocompromised persons should only eat food that is fully cooked and should thoroughly wash vegetables and fruits that are consumed raw with uncontaminated water.

A variety of animals, including dogs, and cats can get infected with cryptosporidiosis. The disease is caused by the ingestion of the parasite through contaminated water, food, or feces. Cryptosporidium infection in dogs and cats is rare, however when infected, pets can carry the parasite without showing any signs of illness. If dogs are affected by the parasite, they will typically have diarrhea. If you suspect that your pet is ill with cryptosporidiosis, seek medical care from a veterinarian. Always pick up your pet’s waste using a disposable bag and throw it in the garbage. Wash your hands with soap and water after contact with or cleaning after your pet.

DPW is required to test the water at the Druid Lake and Ashburton reservoirs each month for the presence of Giardia and Cryptosporidium as part of DPW’s recently modified Administrative Order on Consent between the City of Baltimore and the Environmental Protection Agency (EPA).

Since the amount of Cryptosporidium that was detected in the water was so minimal, independent laboratory analysis could not determine a source.

Samples were collected on September 19, 2023, and the laboratory analysis findings were reported on September 26, 2023.

Laboratory analyses for Giardia and Cryptosporidium take between 5-7 days to complete.

Cryptosporidium is typically tested in raw water (i.e., water that has not yet been treated). There are no state or federal guidelines for testing and/or reporting Cryptosporidium in finished (i.e., treated) water such as at the Druid Lake and Ashburton Reservoirs. Therefore, DPW has been collaborating with the Maryland Department of Environment (MDE), Environmental Protection Agency, and Maryland Department of Health to develop public notification guidelines based on this event and to ensure that the message of water safety is clearly communicated to the public.

Testing began in late-July 2023, and per the terms of the modified Administrative Order on Consent with the EPA, DPW is required to submit its monthly reports to the EPA and MDE by the fifteenth of each month until the underground tank projects are completed. The samples collected as part of the August 2023 report were negative for Cryptosporidium and Giardia at both Druid Lake and Ashburton Reservoirs.

Functional use of the Ashburton tank is scheduled for November 30, 2023. Functional use of the Druid Lake tank is scheduled for December 30, 2023.