The cysteine proteases of Paragonimus westermani metacercariae are involved in metacercarial excystment, host immune modulation, and possibly in tissue penetration. In order to clarify the origin of the enzymes, 28 and 27 kDa cysteine proteases in metacercarial excretory-secretory products were purified through the FPLC system using Mono Q column chromatography. The polyclonal antibodies to the enzymes were produced in BALB/c mice. Immunolocalization studies revealed that both cysteine proteases were distributed at the linings of excretory bladder and excretory concretions of the metacercariae. It was suggested that the excretory epithelium of P. westermani undertake the secretory function of metacercarial cysteine proteases, in addition to its role as a route for eliminating waste products.
Animals ; Chromatography, Liquid ; Computational Biology ; Cysteine Endopeptidases/analysis/isolation & purification/*physiology ; Immunohistochemistry ; Mice ; Mice, Inbred BALB C ; Paragonimus/anatomy & histology/*enzymology ; Support, Non-U.S. Gov't

Paragonimus harinasutai metacercariae were found in a species of freshwater crab, Indochinamon ou, collected in a small stream of Namback District, Luang Prabang Province, Lao PDR. Adult flukes were recovered after experimental infection of the metacercariae to dogs. Metacercariae were round or slightly elliptical, 0.666 x 0.626 mm in average size, and had a thin cyst wall of about 20 microm in thickness, a black excretory bladder, convoluted ceca, and some pinkish materials in the body. Adults were somewhat elongated, 95.2 x 36.5 mm in average size, covered with single-tipped tegumental spines, had a smaller oral sucker than the ventral sucker, a moderately branched ovary, and 5-6 lobulated testes. Eggs were ovoid and bilaterally symmetrical in shape, 79 x 45 microm in average size, and had a uniformly thickened shell. By the present study, it has been confirmed that I. ou is a new second intermediate host for P. harinasutai.
Animals ; Crustacea/*parasitology ; Disease Reservoirs/*parasitology ; Dogs ; Female ; *Host-Parasite Interactions ; Humans ; Laos ; Male ; Paragonimiasis/*parasitology ; Paragonimus/anatomy & histology/*isolation & purification/ultrastructure ; Shellfish/*parasitology

OBJECTIVESTo determine the natural crustacean host, the Paragonimus species, and to investigate the potential host-parasite relationship between Manipur Paragonimus and some of the laboratory animals.

METHODSThe laboratory animals such as puppies, albino rats and Swiss mice were infected orally with metacercariae isolated from the fresh water crabs, Potamiscus manipurensis. The fecal specimens of the experimentally infected animals were examined microscopically for Paragonimus eggs at regular intervals. The animals were autopsied on days 35 to approximately 328 after infection and the isolated worms were flattened between glass slides and fixed in 70% alcohol. The worms were stained with carmine and mounted with Canada balsam for morphological studies. The eggs were collected in 5% formol saline solution for microscopy. The flukes were classified into 4 developmental stages.

RESULTSA total of 11 worms, 5 mature, 5 immature and 1 pre-adult were recovered. The morphological features of the metacercariae, worms and eggs were similar to those of Paragonimus heterotremus.

CONCLUSIONManipur is one of the rare areas in the world where Paragonimus heterotremus is prevalent and the puppies are ideal experimental animal host. This species may be one of the important causes of paragonimiasis in animals and humans in Manipur.

Animals ; Animals, Laboratory ; Brachyura ; parasitology ; Dogs ; parasitology ; Host-Parasite Interactions ; India ; epidemiology ; Lung Diseases, Parasitic ; epidemiology ; parasitology ; Mice ; parasitology ; Paragonimiasis ; epidemiology ; parasitology ; Paragonimus ; anatomy & histology ; isolation & purification ; Rats ; parasitology