Contagion and Consequences

• Infected raccoons shed B. procyonis eggs in their feces. The eggs become infective after three to four weeks in the environment, according to PetEducation.com. Intermediate hosts such as mice, squirrels, birds and dogs accidentally ingest the infected eggs directly or indirectly by grooming their feathers or fur. Healthy dogs and other animals can also get infected by eating infected hosts. As larvae migrate, they grow larger, causing extensive mechanical damage and strong inflammatory response. PetEducation.com states that about 5 to 7 percent of larvae migrate to the brain.
  
  

Symptoms and Signs

• Larvae migrating through a dog's body organs produce symptoms such as fever, enlarged liver and respiratory problems. If larvae migrate to the eyes, a dog exhibits photophobia (light sensitivity) and vision loss. According to Michigan's Department of Natural Resources and Environment, non-raccoon hosts initially exhibit a head tilt and inability to walk properly or climb. As illness progresses, wildlife lose their fear of humans. Dogs and other animals circle, roll on the ground, fall over, lie on their sides paddling their feet, become totally recumbent, comatose and die.
  
  

Diagnosis

• Ophthalmologic examination reveals larvae in the retina of the dog's eye. According to PetEducation.com, diagnosis is also made through history, clinical signs and serologic (blood serum) testing. Raccoon roundworms are also detected by PCR (polymerase chain reaction) tests wherein nucleic acid, DNA or RNA are isolated and amplified. Zoologix, a California molecular diagnostic testing company for animals, states, "With this more advanced approach, preventive screening and environmental surveys are possible, enabling identification of animal carriers and even contaminated soils."
  
  

Prevention

• Because raccoon roundworm is so dangerous and has no cure, prevention is the only method of fighting the disease. Dogs should not be allowed to roam in rural or city areas known to be frequented by raccoons. They should be closely monitored to prevent their coming in contact, or even eating, infected hosts such as squirrels, other rodents and birds. Because B. procyonis eggs are highly resistant to common disinfectants, including bleach, a dog's kennel areas, if suspected of contamination, should be treated by professionals with a 50/50 solution of xylene and ethanol. Larger kennel areas are best decontaminated by a portable propane torch, according to PetEducation.com.
  
  

Expert Insight

• PetEducation.com states, "Remember that the eggs must be in the environment three to four weeks before they are infective. So, fresh raccoon feces do not contain infective eggs. Infective eggs are found in fecal matter that is already disintegrating and may be less obvious in the environment. Like eggs of the roundworms of cats and dogs, B. procyonis eggs can survive for years in the environment." Because of this, it's best to keep a close eye on dogs even when raccoons aren't known to currently frequent the area.