Indochinamon ou (Crustacea: Potamidae) as a New Second Intermediate Host for Paragonimus harinasutai in Luang Prabang Province, Lao PDR

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.

Excretory bladder: the source of cysteine proteases in Paragonimus westermani metacercariae

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.

Scanning electron microscopy of newly excysted metacercariae of Paragonimus westermani-like, Nakhon Nayok, Thailand.

Scanning electron microscope (SEM) observation of surface structure was done on newly excysted metacercariae of Paragonimus westermani-like (Nakhon Nayok, Thailand). The surface of the body was covered with numerous single-pointed tegumentary spines, large dome-shaped papillae, small one with a pit, and small one with a smooth surface were situated around the suckers. There were 27 to 30 of the small dome-shaped papillae with a pit around the oral sucker and 10 to 13 of the small ones with a smooth surface around the ventral sucker. The present report is the new record of excysted metacercariae of P. westermani-like (Nakhon Nayok, Thailand) by SEM.

A case of paragonimiasis in a civet cat with a new Paragonimus sub species in Manipur, India.

A case of paragonimiasis in a civet cat with a new Paragonimus sub species in Manipur, India.

La válidez del nombre específico en Paragonimus peruvianus Miyazaki, Ibañez y Miranda, 1969 / Validity of the species name in Paragonimus peruvianus Miyazaki, Ibáñez and Miranda, 1969

Con el propósito de restituir el nombre específico de Paragonimus peruvianus que había sido retirado por Miyazaki en 1980 y considerado como sinónimo de P. mexicanus, se ha efectuado un estudio comparativo de los caracteres morfológicos de los parásitos adultos intrapulmonares, de las redias, cercarias y de los huevos. Los especímenes adultos difieren en la forma y tamaño de los testículos, vesícula seminal, espermateca, canal de Laurer. Las cercarias se distinguen por el número de disposición de las glándulas de penetración internas y externas y por la presencia de pseudoventosa en P. mexicanus más no en P. peruvianus. Las redias se diferencian por el tamaño del cuerpo y el diámetro de la farínge. Y los huevos por su longitud y por la rugosidad de su superficie. Tales diferencias morfológicas permiten asegurar que P. peruvianus y P. mexicanus son especies diferentes

The route of migration of Paragonimus siamensis Miyazaki & Wykoff, 1965 in the white rat.

After they were ingested, the metacercariae of Paragonimus siamensis excysted in the stomach, penetrated through the stomach wall and the first 3 centimetres of small intestinal wall into the abdominal cavity, then penetrated into abdominal muscle. The worms stayed in abdominal muscle for about one week, then appeared again in the abdominal cavity before entering the pleural cavity and lungs; they also appeared in thoracic muscle, diaphragm, liver, and muscle of foreleg. The worm's size increased steadily until worm reaches sexual maturity then body size increased slowly. Genital primordia could be recognized at one week, of the reproductive system vitellaria were the last to appear at week 5, and eggs were first seen in the 7-week-old worms.

Experimental infection of Oncomelania quadrasi with Paragonimus ohirai.

Two hundred Oncomelania quadrasi collected from Leyte, Philippines were exposed to infection with Paragonimus ohirai, a rodent type lung fluke. In a group, each snail was exposed individually to 10 miracidia hatched from eggs which were brought from Japan to the Philippines. In another group, 100 snails were placed in a Petri dish and P. ohirai miracidia were added to provide 10 per snail. The observations were made each successive week after exposure. All the snails examined were positive for the larvae of P. ohirai. Nine-ten weeks after exposure, many cercariae were recognized. It was proved that O. quadrasi is highly susceptible to P. ohirai.