US Air Force  

Air Force Public Health

Total Force Integration

Integrity Service Excellence

USAF -- Public Health Information and Resources

Home ANG Specific Resources Arthropod-Borne Diseases Arthropod Taxonomy CBRNE
Communicable and Pandemic Diseases Deployment Medicine Disease Surveillance Epidemiology
Force Health Management Food-Borne Illnesses Hearing Conservation Helminthology Infectious Diseases Medical Entomology Medical Intelligence Occupational Health Parasitology PDHRA
PH Officer   PH Technician   Travelers' Health Tropical Medicine Zoonotic Diseases
Microsoft Office Tutorials Palm OS Resources
 

Allergic Sensitivities

Arthropod Infestations

Bacterial Diseases

Bites and Scratches

Cestode Zoonoses

Fungal Infections

Nematode Zoonoses

Protozoan Diseases

Rickettsial Diseases

Trematode Zoonosis

Viral Diseases

 		Zoonotic Diseases

Cestode Zoonoses - HYMENOLEPIS DIMINUTA

(Rat Tapeworm Infection)

AGENT:

Hymenolepis diminuta is the common tapeworm of rodents. Size varies from 100-600 mm.

RESERVOIR AND INCIDENCE

Rodents, many arthropods (fleas, beetles, and cockroaches) serve as intermediate hosts.

TRANSMISSION:

Rodents and humans are infected by accidentally swallowing the infected arthropods, usually in cereals or stored products.

DISEASE IN ANIMALS:

Mild catarrhal enteritis with diarrhea occurs if the infection is heavy.

DISEASE IN MAN:

Light infections are generally asymptomatic. Heavy infections may cause diarrhea, abdominal pain, anorexia, vomiting, weight loss, and irritability, particularly in young children.

DIAGNOSIS:

Infections are diagnosed by finding characteristic eggs in feces; proglottids are usually not seen.

TREATMENT:

Niclosamide or praziquantel.

PREVENTION/CONTROL:

Eliminate rodents and insects in facilities.

LIFE CYCLE:

Life cycle of Hymenolepis diminuta

Eggs of Hymenolepis diminuta are passed out in the feces of the infected definitive host (rodents, man) .  The mature eggs are ingested by an intermediate host (various arthropod adults or larvae) , and oncospheres are released from the eggs and penetrate the intestinal wall of the host , which develop into cysticercoid larvae.  Species from the genus Tribolium are common intermediate hosts for H. diminuta.  The cysticercoid larvae persist through the arthropod's morphogenesis to adulthood.  H. diminuta infection is acquired by the mammalian host after ingestion of an intermediate host carrying the cysticercoid larvae .  Humans can be accidentally infected through the ingestion of insects in precooked cereals, or other food items, and directly from the environment (e.g., oral exploration of the environment by children).  After ingestion, the tissue of the infected arthropod is digested releasing the cysticercoid larvae in the stomach and small intestine.  Eversion of the scoleces occurs shortly after the cysticercoid larvae are released.  Using the four suckers on the scolex, the parasite attaches to the small intestine wall.  Maturation of the parasites occurs within 20 days and the adult worms can reach an average of 30 cm in length .  Eggs are released in the small intestine from gravid proglottids that disintegrate after breaking off from the adult worms.  The eggs are expelled to the environment in the mammalian host's feces . (Source CDC)