Epidermal tumors of rainbow smelt with associated virus.

Epithelial tumors of the skin occurred in landlocked populations of rainbow smelt (Osmerus mordax) in several lakes in New Hampshire (USA) during the spawning runs. Histologically, these were noninvasive epithelial cell lesions. Herpesvirus-like particles could be seen in the nucleus and cytoplasm. The lesions occurred in both males and females. Prevalence which varied annually, was as high as 30%.

Variation in composition of media and reagents used in the preparation of cell cultures from human and other animal tissues: Dulbecco's, Earle's, and Hanks' balanced salt solutions.

When comparison was made of directions given for three salt solutions commonly used in cell culture preparations and identified as Dulbecco's, Earle's, and Hanks', variations in composition were found. Some significantly alter the suitability of the materials for the intended use. Other differences may have less effect. This brief review reveals a tendency among researchers to follow procedures obtained from colleagues for the preparation of laboratory reagents and media, to cite the original publication rather than their colleagues' work as the source of the information, and to fail to compare the two for differences. Some failures in cell culture propagation may be attributed to similar instances with other published but incorrectly cited work. Tables are provided that facilitate comparison of the correct original formulations with variants from selected published sources.

Survival of duck plague virus in water from Lake Andes National Wildlife Refuge, South Dakota.

An isolant of duck plague herpesvirus from the Lake Andes Refuge outbreak was seeded in raw and filter-decontaminated water from two locations on the refuge, held at 4 C, and assayed for infectivity intermittently over a period of 2 mo. From an initial level of about 10(5) PFU per ml, infectivity in the filtered samples uniformly dropped to about 10(4) PFU per ml. Infectivity in the raw samples declined much more rapidly; infectious virus remaining at the end of 2 mo (ca. 10(1) PFU per ml) was only about 0.01% of that originally seeded.

Fine structure of an unidentified protozoon in the epithelium of rainbow trout exposed to water with Myxosoma cerebralis.

An intracellular protozoon was discovered in the epithelium of young rainbow trout (Salmo gairdneri) exposed for as short a time as 1 hr to water known to contain infective stages of Myxosoma cerebralis. Light- and electron-microscopic examination of this tissue revealed what appeared to be a proliferative stage (presumptive schizont) of a sporozoon; other possible stages in the life cycle were also observed. The relationship of this unidentified protozoon of M. cerebralis remains unresolved.

Duck viral enteritis: a comparison of replication by CCL-141 and primary cultures of duck embryo fibroblasts.

Cultures of primary cells and a line of fibroblast-like cells from the Pekin duck were both compared for their replication of the herpesvirus of duck viral enteritis. The two kinds of cells were equally accurate for quantifying virus upon isolation. Also, one-step growth curves showed that in both kinds of cultures new virus appeared by the 18th hour and that infectivity peaked at about 36 hours. Primary cultures yielded about 5.6 times as much virus as did the cell line, though plaques were more easily discerned in the latter. Because of availability, uniformity, and their known health history, CCL-141 cells offer some advantages for work with the agent of duck viral enteritis.

Morphogenesis of marek's disease virus in feather follicle epithelium.

Three evaluative systems, immunodiffusion, fluorescent antibody (FA), and electron microscopy (EM), were used to follow the morphogenesis of Marek's disease virus in inoculated chickens. Of the three, EM and FA were the most sensitive in detecting early stages of infection. Virus particles were found in skin biopsy specimens as early as 12 days post inoculation. Immature naked particles appeared first in the nucleus; later particles were enveloped in the cytoplasm and enclosed in cytoplasmic inclusion bodies. No evidence for continued virus replication was seen in feather follicles after an initial burst of heavy virus production, which lasted several weeks. Residual virus, however, was found occasionally in cytoplasmic inclusion bodies within keratinized material near the feathers. This was believed to contribute to the long-term shedding of infectious virus into the environment.