Raccoons can be successfully treated with several anthelmintics to kill the adult worms. In the event of the death of the human, larvae can be detected in microscopic sections of the brain, heart, lungs, eyes, and other affected tissues.
In humans, based on the size of the larvae in the skin or eye lesions, cases of Baylisascaris infection can be determined. A Baylisascaris infection is often suspected by the history and clinical signs observed. Larvae and associated lesions in the brain, eyes, and other tissues can be observed on histopathological examination. In intermediate hosts, the disease can be diagnosed after a postmortem examination. Occasionally sub-adult worms are passed in the feces or vomitus. In raccoons, infection with Baylisascaris can be confirmed by recovering and identifying the adult worms (postmortem examination) or by fecal flotation (live animal) to identify characteristic ascarid eggs in the feces. The affected individuals may experience nausea, a lethargic feeling, incoordination, and loss of eyesight. In humans, pathological lesions observed consist of skin irritations (cutaneous larval migrans) and eye and brain tissue damage (visceral larval migrans) due to the random migration of the larvae. As the clinical illness progresses the animal may lose its fear of humans, circle, roll on the ground, fall over, lay on its side, and paddle its feet, become totally recumbent, comatose, and finally die. The affected animal will initially exhibit a head tilt and an inability to walk and/or climb properly. In intermediate hosts unusual behavior is generally observed. If small numbers of larvae are involved in the migration, there may be no clinical signs observed.įatal or severe central nervous system disorders have been documented for mice, gray and fox squirrels, ground squirrels, woodchucks, nutria, beavers, domestic quail, partridges, pigeons, exotic turkeys, emus, captive cockatiels, captive prairie dogs, foxes, armadillos and porcupines. Larvae may also cause eye disorders by migrating through the ocular tissues. This is the result of damage caused to the brain and spinal cord by the larvae. Usually changes in behavior are seen due to central nervous system disorders. Migration of large numbers of larvae may cause liver and lung damage. The animals usually seen with clinical and pathological signs caused by Baylisascaris are the intermediate hosts (mice, woodchucks, squirrels, rabbits, and birds). In heavy infections, intestinal obstructions or a rupture of the intestinal tract may occur, due to the large number of parasites present. In raccoons usually there are no clinical or pathological signs observed. The parasite commonly migrates to the eyes and the brain. In humans, embryonated eggs are ingested, the eggs hatch, and the larvae undergo random migration along the skin and through the viscera. If the intermediate host is eaten by a raccoon, the encysted larvae are released and migrate to the small intestine where they develop into the adult stage. The larvae become encysted in small, fibrous nodules in the affected tissue. The larvae then enter the pulmonary veins, pass into the left side of the heart and are distributed throughout the body especially the head, neck and/or thoracic areas. When an intermediate host is involved, embryonated eggs are ingested, the eggs hatch, the larvae penetrate the intestines and migrate through the liver and the lungs. This may occur via the mother's egg-contaminated body or from the local environment of the den (soil or vegetation). Raccoons, especially young ones, become infected directly by accidental ingestion of these eggs. Naturally infected raccoons shed eggs (millions daily) in their feces and, under adequate temperature and moist conditions, a larvae will develop within the egg (embryonated) and can be infective (2 nd stage larva) in 11-14 days. procyonis can occur either directly or via an intermediate host. There are several intermediate hosts that have been diagnosed as having a Baylisascaris infection: mice, squirrels, rabbits, birds, woodchucks, and chipmunks. In Michigan, the parasite has commonly been seen in raccoons statewide. Prevalence of infections ranges from 3.4% to nearly 100% of all raccoons sampled. procyonis has been reported from numerous states, but probably occurs wherever the raccoon inhabits. They are tan-white in color, cylindrical and taper at both ends. Adult worms measure 15 to 20 cm in length and 1 cm in width. The raccoon roundworm ( Baylisascaris procyonis) is the common large roundworm or ascarid found in the small intestinal tract of raccoons.