Nematospiroides dubius as a vector for Salmonella typhimurium.

Salmonella typhimurium within the 3rd stage larvae of Nematospiroides dubius was shown to infect mice, evidenced by prolonged shedding of salmonellae in the feces. Numbers of S typhimurium needed to infect mice were approximately 1,000- fold less if incorporated within the 3rd-stage larvae of N dubius. Results of these experiments demonstrate that nematode parasites may act as a vector for pathogenic species of enteric bacteria.

An outbreak of bovine cysticercosis in California.

Approximately 4.75% of the animals sent to slaughter from a southern California feedlot during a 9-mo period were found to be infected with the cysticercus of Taenia saginata. An investigation of possible transmission sources revealed that the feedlot was the most likely site of infection. One feedlot worker was found to be infected with T. saginata, and the pen infection patterns and other physical relationships indicated that he was the source of infection. The following recommendations were made: 1) treatment of the infected worker; 2) education of employees as to the mode of transmission and personal hygienic practices; 3) addition of sanitary facilities; 4) maintenance of animal source and destination records; 5) inauguration of a surveillance program to include parasitologic examination of employees prior to employment and periodically thereafter; and 6) restriction of unauthorized personnel from critical areas.

Utilization of propionic acid by the L4 and adult stages of Cooperia punctata (Nematoda: Trichostrongylidae) grown in vitro.

Cultures of Cooperia punctata, a nematode parasitic in cattle, were studied in Ae medium at a pH of 7.2 to 7.3 under air. In fourth and fifth stages of development, they absorbed or otherwise took into their free pool and tissues, carbon derived from 14C-labeled sodium propionate and converted, by pathways not elucidated, a portion of this carbon into protein and lipid fractions. Thirty minutes postincubation in balanced slat solution was adequate to reduce the amount of isotope in the nematode gut to a constant level. Activity from specifically-labeled 14C-propionate was recovered (as glucose pentaacetate) from worm glucose and from CO2 evolved from cultures consisting of L4 and adult stages. Use of propionate by these worms, for whatever metabolic purpose, would result in depriving the ruminant host of some of its necessary glucogenic precursors, and could account for a specific pathogenic mechanism attendant to heavy infections with this parasite.

An epidemic of pediculosis capitis.

An epidemic due to Pediculus humanus capitis occurred in the public schools of Buffalo, New York, in the winter of 1973. A survey at one elementary school showed that 20% of whites and no blacks were infested, and a city-wide prevalence survey during the academic year September 1972 to May 1973 showed that 7.2% of all pupils were infested. An epidemiological investigation showed that sex, age, race, socioeconomic status, crowding, method of closeting garments, and family size influenced the distribution of pediculosis but that hair length apparently was not a factor. Poverty and ignorance appeared to contribute to the persistence of infestation.

Adult heartworms in arteries and veins of a dog.

A 5-year-old terrier-type dog with a 3-week history of progressive lameness, swelling, and pain in the left hindlimb suddenly became paralyzed in the right hindlimb. Because of a poor prognosis, the dog was euthanatized. Necropsy revealed mature heartworms (Dirofilaria immitis) in the femoral arteries as well as in the right side of the heart and pulmonary arteries. Extensive ischemic necrosis in the muscles of the hindlimbs was attributed to occlusion of the femoral arteries by heartworms.

Epidemiology of an outbreak of head lice in Georgia.

An outbreak of head lice infestation (pediculosis) occurred in elementary school children in Barrow County, Georgia, in January 1974. An investigation was initiated to define the magnitude of the outbreak, determine factors that contribute to transmission, and disseminate information on control. All elementary school children in the county were examined for head lice and answered a questionnaire. Fifty-three (3%) of 1,783 white pupils were infested, but none of the 500 black pupils was infested. Distribution of infestation in the white pupils was influenced by grade, bed-sharing, socioeconomic status, infestation of other family members, crowding in the home, and family size; distribution was not influenced by hair length or the sex of the pupil. Recommendations for control based on the results of the investigation included procedures for identifying and processing cases, distributing free pediculicides, continuing surveillance, educating school personnel and parents on how to control the parasite.

Detection of activity for various anthelmintics against in vitro-produced Cooperia punctata.

The in vitro-grown parasitic stages of Cooperia punctata were used to evaluate 28 compounds with different kinds and degrees of in vivo activity. Using presumptive and confirmatory tests, it was possible to establish a group order of in vitro potency that compared favorably with an order based on established in vivo use of these compounds. The procedure lends itself to evaluating activity against a given parasitic growth stage and gives a quantitative estimate (range) of the concentration that produces 50% nematode kill. The system was most successful in detecting compounds with in vivo activity for C punctata, followed in order by compounds active against Cooperia spp, other gastrointestinal nematodes of ruminants, and other nematodes of non-bovine hosts. The procedure showed some differentiation between activity against nematodes versus that against cestodes, trematodes, and arthropods. The system permits considerable flexibility in experimental design, thus making possible the acquisition of the particular information desired. In addition to establishing lethal effects on the nematode, the procedure detected compounds with nematode-anesthetizing effects. The results indicate this in vitro system can be used with some expediency as a preliminary screening method in the search for new anthelmintic compounds.

An epizootic of bovine cysticercosis.

In March, 1973, a large feedlot near Phoenix, AZ, reported an increased incidence of bovine cysticercosis. Approximately 10% of cattle sent to slaughter from January to April, 1973, were infected with the cysticercus stage of Taenia saginata. One employee who worked at the feed mill and loaded hay in the fields was also found to be infected with T saginata. Recommendations for control of similar epizootics included educating employees about mode of transmission and improved personal hygiene, the inauguration of a surveillance program that included examination of employees prior to employment and periodically thereafter, maintenance of animal source and destination records, restriction of unauthorized personnel to critical areas, and periodic microbiologic assay of water supply.