Zoonoses are infectious diseases that can be transmitted from animals to humans or from humans to animals. Transmission most commonly occurs between humans and pets or farm animals.
The list of zoonoses which involve household pets is extensive and here are a few more common ones: Rabies, Leptospirosis, intestinal parasites, Toxoplasmosis and Cat Scratch Fever.
Dogs become infected with Leptospires when contaminated water or urine comes in contact with scratches in their skin, and also through consuming reproductive secretions, or infected tissues. The disease progresses quickly causing fever, joint pain, weight loss, and generalized illness. The organism then becomes established in the kidneys where it multiplies, eventually leading to kidney failure. Depending on the type of leptospire involved, other organ failure (especially liver) can be expected as well.
It is a serious life threatening disease. The urine from infected animals will contaminate the environment, particularly the soil and water, where the bacteria can survive for months. People become infected by coming in contact with bacteria shed by infected animals, especially if there are minor scratches in their skin. Infection can also occur through mucous membranes (eyes, mouth) or by drinking contaminated water.
To help prevent Leptospirosis infection keep your dog vaccinated against Leptospirosis. The vaccine does not provide 100% protection but offers significant immunity. It is important to get your pet vaccinated again even if it gets leptospirosis because it can still get infected with a different strain of leptospires. Also, keep rodent problems under control. Rodents can carry and spread the bacteria that causes this disease.
ROUNDWORMS (dogs and cats)
Roundworms are very prevalent intestinal parasites in cats and dogs. Cats and dogs become infected from the environment, through nursing, or by ingesting infected prey, or from their infected mothers during pregnancy. The roundworm egg is passed into the host's feces and has the ability to remain infective for months to years and survive very harsh environments (even MN winters!). Once ingested, the infective egg will become a larva and migrate through the host's internal tissues, such as the lungs or the liver. Eventually, it returns to the intestines as an adult, and the cycle starts over.
Clinical signs are usually related to GI upset with diarrhea and vomiting, and young pets are more severely affected.
The canine roundworm, is the predominant cause of a serious condition called "visceral larva migrans" in humans. Most victims are children. The infection happens by accidental consumption of eggs in soil, followed by a the larva's migration through the human tissue (classically to the eye), where it dies, and generates an extreme inflammatory reaction. If the worm dies within the human eye, permanent partial blindness usually results.
It is important for parents to be aware of this hazard. Proper hygiene, (hand-washing, regular cleaning of the yard, and leash laws) will reduce the chance of infection. Monthly pet deworming will reduce environmental contamination. Cats should be kept away from children's sandboxes where Toxocara felis eggs can contaminate the play area. Monthly heartworm prevention will reduce the infection in dogs.