Enhancement of Campylobacter jejuni virulence by serial passage in chicks.

Four isolates of Campylobacter jejuni were studied to determine changes in virulence following six serial passages in chicks. Chicks that received invasive isolates exhibited diarrhea and depressed weight gain. Immature mice were used to assess virulence of the passaged isolates of C. jejuni. Nine-day-old mice infected with passaged isolates showed lethargy, dehydration, depression, decreased weight gain, and occult blood in feces. Mouse pups inoculated with the third and sixth chick passage levels of an invasive isolate showed significant depression in mean daily weight gain and elevated mortality compared with controls and subjects inoculated with unpassaged isolates. This study demonstrated enhancement of virulence in a C. jejuni isolate following chick passage. In contrast, three other passaged isolates failed to show any consistent increase in virulence.

A descriptive study of dairy goat predation in Louisiana.

Questionnaires concerning herd size, housing and management, and previous instances of predation were mailed to 124 goat owners in Louisiana. Postcards were mailed over a period of one year on a monthly basis, to the 84 individuals who responded to this questionnaire. Owners were asked to indicate whether they had seen predators on their property and whether any goats were injured or killed by the predators. Upon receipt of any postcard with a "yes" answer to either of these questions, a telephone interview was conducted to determine the exact circumstances of predator experience. The interview format included time, physical circumstances, and detailed questions about the actions of the predator and the goats. In 85% of the cases, the predators sighted were reported as dogs, and most of these were thought to be pets, rather than wild. Instances of attacks occurred most frequently during periods of reduced light. No clear seasonal pattern of attacks emerged. Four management factors were associated with a reduction in number of attacks; penning the goats at night, use of a night light, proximity of the herd to an occupied residence, and presence of a dog.

Evaluation of the origin of Mycobacterium leprae infections in the wild armadillo, Dasypus novemcinctus.

An enzyme-linked immunosorbent assay (ELISA) using the phenolic glycolipid-1 (PGL-1) antigen of Mycobacterium leprae and cross-reactive antisera specific for human IgM was developed to detect IgM antibodies to M. leprae in the nine-banded armadillo (Dasypus novemcinctus). Statistical definitions for positive and negative interpretations in the ELISA were developed by screening animals recently captured and experimentally inoculated with M. leprae. The ELISA was shown to have high sensitivity and specificity. Modern day armadillos of central Louisiana were observed to have a PGL-1 antibody prevalence rate as high as 20%, and a clinical disease rate as high as 5%. A retrospective serological survey of 182 armadillos taken in the years 1960-1964 and predating the use of armadillos in leprosy research was used to evaluate the 1968 environmental contamination hypothesis for the origin of M. leprae infections in the wild armadillo. Antibodies to the apparently species-specific PGL-1 antigen were detected in 17 of the samples taken in 1960-1964. Absorption with whole M. leprae, M. intracellulare, M. terrae, M. rhodesiae, M. scrofulaceum, M. diernhoferi, M. kansasii, M. phlei, M. avium, BCG, and 2 new armadillo-derived mycobacterial species showed these antibody reactions to be specific for PGL-1. Apparently, M. leprae was enzootic in armadillos as early as 1961, and original infection of these animals could not have occurred in 1968.

Visceral larva migrans: a risk assessment in Baton Rouge, Louisiana.

Visceral larva migrans, VLM, is a disease of young children. Due to lack of awareness of the disease as well as its non-specific symptomology, a survey of the potential risk of acquiring the disease was conducted in the Baton Rouge, Louisiana area. The greatest number of dogs showing positive results to tests for the presence of the eggs of Toxocara canis were those less than one year of age. Very few of the soil samples collected from twenty different parks/playgrounds were found to contain eggs of T. canis. A higher percentage of soil samples from individual yards proved to be contaminated with the eggs of the parasite. Even though the incidence of VLM in Baton Rouge is reported to be quite low, the potential for the infection certainly is present. Veterinarians must be prepared to take a leading role in the education of their clients as to the potential of the disease for the children associated with new puppies, and the measures parents can take to reduce the exposure potential.

Leprosy in sub-human primates: potential risk for transfer of M. leprae to humans.

Twenty six owned monkeys were examined in Andhra Pradesh, India during the period May-July, 1982. The prevalence rate among humans in daily contact with these monkeys was 98.6/1000. None of the monkeys examined had any evidence of current infection with M. leprae but six were in daily contact with individuals who had leprosy. All six of these monkeys were used for begging and had daily physical contact with large numbers of people, particularly children.

Prevalence of Mycoplasma and Chlamydia in the nasal flora of dairy calves.

Nasal swabs from dairy calves in 20 selected herds were collected once in each of three sampling periods in one year and cultured for mycoplasmas and chlamydiae. Seventy-seven of 411 calves (19%) and 16 of 20 herds (80%) were positive for mycoplasmas at least once throughout the year, and all of 378 calves sampled from the 20 herds were negative for chlamydiae. Thirty-one percent of the isolates were Mycoplasma bovirhinis; other species isolated less frequently were Mycoplasma bovis, Mycoplasma arginini, and Acholeplasma laidlawaii. There was no evidence of respiratory tract disease at the time of sampling in calves studied.

Prevalence of bovine herpesvirus-1, bovine oral diarrhea, parainfluenza-3, bovine adenoviruses-3 and -7, and goat respiratory syncytial viral antibodies in goats.

Sera from healthy goats were collected during October 1979 through October 1980. These sera were tested for bovine herpesvirus-1 (BHV-1), bovine viral diarrhea virus (BVDV), parainfluenza-3 (PI-3) virus, bovine adenoviruses (BAV) -3 and -7, and goat respiratory syncytial virus (GRSV) antibodies by microtitration virus-neutralization test. The number of herds with seropositive goats for each virus were: 5/38 (13.2%) for BHV-1; 9/38 (23.7%) for BVDV; 8/38 (21.1%) for PI-3 virus; 1/38 (2.6%) for BAV-3; 15/38 (39.5%) for BAV-7; and 26/34 (76.5%) for GRSV. Seropositive rates for each virus for the individual goats tested were: 6/502 (1.2%) for BHV-1; 9/498 (1.8%) for BVDV; 49/458 (10.75) for PI-3 virus; 1/487 (0.025) for BAV-3; 40/448 (8.9%) for BAV-7; and 166/332 (50.0%) for GRSV.

The need for integrated control programs for zoonoses affecting livestock.

Prior to recognition of etiologic agents of zoonoses (infections transmitted between animals and man), physicians encountered these illnesses in man and veterinarians observed them in animals. As the agents were identified, interspecies relationships (and spread) became evident and control programs evolved without consideration of cost-effectiveness. Today, the public demands efficient use of financial resources. Human health as well as economic losses are concerns of animal health agencies. Zoonoses affecting livestock, though not major priorities among public health agencies, cannot be ignored. It seems economical, therefore, to combine the efforts of these agencies in zoonoses control. This would benefit human health by reducing the animal reservoirs and the livestock industry will benefit by lowered production costs.

Interfacing professional training in health maintenance and preventive medicine.

Because of emerging economic realities of the latter half of this century, the practice of preventive medicine, as opposed to curative medicine, is becoming essential in developed and developing countries. This holds true in veterinary medicine as well as in human medicine, and as we become increasingly aware of this fact, we also recognize the increasing interdependence of both fields. To determine the extent to which veterinarians are prepared to deal with this change in emphasis, two surveys have been prepared; one directed to various specialty groups within the profession and the other directed to schools of veterinary medicine. The first survey was designed to identify areas in which veterinarians felt their training had been deficient relative to decision making in applied preventive medicine. The second survey queried the schools to determine what changes had been made in their curricula to remedy these inadequacies.

Development of a health and safety program at the Louisiana State University School of Veterinary Medicine.

An accident prevention and zoonotic disease control program at the School of Veterinary Medicine, Louisiana State University, was developed by a Health and Safety Committee comprised of members from all instructional departments. The program incorporated safety educational input during the basic, preclinical, and clinical years; a standardized accident reporting procedure; rabies vaccination, with serologic evaluation; a blood serum bank; and recommendations for future control procedures.