Seasonal and yearly population dynamics of two exotic helminths, Camallanus coti (Nematoda) and Bothriocephalus acheilognathi (Cestoda), parasitizing exotic fishes in Waianu Stream, O'ahu, Hawaii.

Exotic poeciliid fishes introduced into Hawaiian freshwaters are responsible for the introduction of several exotic parasites, of which the most important are Camallanus cotti and Bothriocephalus acheilognathi in terms of potential disease threat to native stream fishes. This roundworm and tapeworm are the most prevalent and abundant freshwater fish helminths in Hawaiian streams. This study examined the seasonal and yearly population structure of C. cotti and B. acheilognathi to determine if the tropical Hawaiian environment characterized by low climatic variability permits continuous opportunities for parasite transmission regardless of time of year. Camallanus cotti displayed seasonal differences in prevalence and mean abundance, whereas B. acheilognathi did not. Camallanus cotti prevalence and mean abundance were higher in the Hawaiian summer (47.7%, 0.79) than in winter (25.8%, 0.36). A seasonal relationship of C. cotti levels is likely explained by extensive rains associated with the Hawaiian winter season, which may act to decrease parasite transmission by flushing infected poeciliid hosts, intermediate copepod hosts, and possibly free-living infective worm stages downstream. Bothriocephalus acheilognathi displayed low prevalence and mean abundance in both summer (4.0%, 0.06) and winter (6.5%, 0.07), and it may be difficult to detect seasonal changes due to these low levels. Camallanus cotti prevalence and mean abundance remained relatively constant from the summer of 1995 to the summer of 1999, indicating that levels of this roundworm are stable in Waianu Stream. Whereas B. acheilognathi prevalence and mean abundance were low during the summer of 1995 and the summer of 1997, a dramatic peak in prevalence and mean abundance was observed in the summer of 1998 (41.2%, 1.06), with levels decreasing sharply in the summer of 1999 (4.4%, 0.07). It appears that B. acheilognathi also is present in stable populations at low levels, even though levels rose sharply during a single year.

The development of Procamallanus (Spirocamallanus) neocaballeroi (Nematoda: Camallanidae), a parasite of Astyanax fasciatus (Pisces) in Mexico.

The development of the nematode Procamallanus (Spirocamallanus) neocaballeroi (Caballero-Deloya, 1977), an intestinal parasite of the characid fish, Astyanax fasciatus (Cuvier) in Mexico, was studied in the experimental copepod intermediate host, Mesocyclops sp. After the copepod's ingestion of free first-stage larvae of the nematode, these penetrate into the haemocoel of the intermediate host; they moult twice (on the 3rd and 4-5th day p.i. at 21-22 degrees C) before they attain the third, infective stage. The third-stage larva already possesses the large buccal capsule subdivided into an anterior broad portion with eight spiral thickenings (as observed in lateral view) and a narrow posterior portion, and its tail tip bears three conical processes. The definitive host acquires infection by feeding on infected copepods; in the intestine of this fish, the nematode larvae undergo two more moults (on the 10th and 14-15th day p.i. at 25-32 degrees C) before attaining their maturity. The prepatent period is approximately two months.

Procamallanus diacanthum n. sp from the intestine of marine fish johnius diacanthus, India

Se describe una nueva especie de nematode de la familia camallanidae railliet et Henry, 1915 del intestino del pez de mar johnius diacanthus (lacépede) de la costa de kalingapatnam. Estos ejemplares no concuerdan con la descripción de las especies del género descritas hasta ahora. Por lo tanto, una descripción detallada y posición taxonómica se dan en este artículo. La nueva especie se caracteriza por sus medidas corporales, estructura de los engrosamientos espirales, posición del anillo nervioso y poro excretorio, ausencia de gubernaculum, número y disposición de las papilas caudales, largo de las espículas y del extremo terminal de la cola. Así, puede ser considerado una nueva especie, procamallanus diacanthum

Description of a new species of the genus camallanus Railliet et Henry 1915 from freshwater fish barbus ticto from Krishna River, Andhra Pradesh India

Se describe una nueva especie de un nematode de la familia camallanidae railliet et Henry, 1915 del ovario del pez de agua dulce barbus (Puntius) ticto (Günther). La descripción se basa en dos ejemplares machos y dos ejemplares hembras, de un gran número de huéspedes examinados. Los ejemplares no concuerdan con descripciones de especies conocidas del género camallanus, en consecuencia, una nueva especie camallanus praveeni ha sido nominada para ubicar los presentes ejemplares. La nueva especie podría ser distinguida por las medidas del cuerpo, la naturaleza de los tridentes, posición del anillo nervioso y del poro excretorio, posición y largo de las espículas, número y posición de las papilas caudales posición de la vulva y forma de extremo de la cola

Seasonal dynamics of Camallanus anabantis infections in the climbing perch, Anabas testudineus, from the freshwater swamps near Kalyani town, West Bengal, India.

The seasonal changes of the nematode Camallanus anabantis Pearse, 1933, in the climbing perch (Anabas testudineus) from the freshwater swamps near Kalyani town, West Bengal, India were studied during the period from February 1988 to August 1989. The nematode exhibited a one-year cycle. Larvated females occurred in the fishes from October to February at a water temperature of 12 degrees-29 degrees C. New infection of fishes occurred from February to May and occasionally in September. The fourth-stage larvae, the males, and the young females (without eggs), although irregularly, were found present throughout the year. Egg-laden females occurred in the fishes in August, October to February, and March.

Identification and characterization of the proteolytic enzymes in the developmental stages of the eel-pathogenic nematode Anguillicola crassus.

The proteolytic activities of homogenates prepared from the second larva (L2) and the third larva (L3) as well as the adult stage of the eel-pathogenic nematode Anguillicola crassus were examined using hemoglobin, azocoll, elastin-orcein, and keratin azure as substrates. Whole bodies of L2 larvae, the anterior third of the bodies of L3 larvae, and the anterior fifth of the bodies of adults were studied. Extracts of L2 contained a trypsin-like proteinase exhibiting a molecular weight of 38,000 Da on gelatin-substrate gel electrophoresis. The proteinase showed a pH optimum at 8 and activity against azocoll and keratin. An apparent molecular weight of 25,000 Da was determined for the trypsin-like proteinase of the L3. This enzyme possessed collagenolytic, keratinolytic and slight elastinolytic activity at an optimal pH of 8. Samples of adults contained an aspartyl proteinase with a molecular weight of 90,000 Da. When hemoglobin was used as the substrate, the enzyme displayed optimal activity at pH 5. It was concluded that the proteinases of the larval stages are penetration enzymes, whereas that of the adult stage is a digestive enzyme.