Nematode Zoonoses - CAPILLARIASIS

AGENT:

The causative agents are Capillaria hepatica (hepatic form), C. philippinensis (intestinal form) and C. aerophila (respiratory form).

RESERVOIR AND INCIDENCE:

C. hepatica and C. aerophila are very rare infections with isolated cases reported from North, Central and South America, Asia, and Europe. C. philippinensis is endemic in certain areas of the Philippines and cases have been reported from Thailand and Japan. Humans are the reservoir for C. philippinensis. With C. hepatica, rodents are the reservoirs. Cats and dogs are the reservoir for C. aerophila. Peromyscus maniculatus (deer mouse) and Clethrionomys gapperi (southern red-backed vole) are the major hosts in North America.

TRANSMISSION:

Humans are infected by eating raw fish containing infective larvae. The worm parasite lives in the intestines of humans and autoinfection occurs. Human feces contain large numbers of ova which contaminate watercourses and infect freshwater fish. Humans may be infected by the ingestion of ova in the soil also.

DISEASE IN ANIMALS:

Infection with C. aerophila causes coughing, sneezing, and nasal discharge in dogs, cats, and foxes. Worms of C. hepatica mature and deposit eggs in liver tissue causing a local chronic inflammatory response in mice and rats.

DISEASE IN MAN:

C. hepatica: acute and subacute hepatitis. The liver lesions consist of enlargements with foci of granulation tissue containing worms and ova.
C. philippinensis: progressive weight and protein loss due to diarrhea and malabsorption. The jejunal villi are obliterated with massive accumulations of worms and ova.
C. aerophila: fever and coughing. Worms present in epithelial lining of respiratory tract causing pneumonitis.

DIAGNOSIS:

Liver or intestinal biopsy, necropsy, clinical signs & symptoms. Fecal exam for ova, larva, or adults.

TREATMENT:

Albendazole, Thiabendazole, Mebendazole.

PREVENTION/CONTROL:

Do not eat uncooked fish and other aquatic animal life in endemic areas. Control rodents and improve hygiene. Prevent pica. Sanitary disposal of feces.