Plant uptake assay to determine bioavailability of inorganic contaminants

A laboratory technique has been developed to rapidly assess the potential uptake of contaminants by plants growing into waste burial sites. A soil-less planting media was used to provide rapid plant growth and reproducible growing conditions. The uptake of contaminants by several plant species grown on uranium mill tailings materials has been examined. The bioavailability of Mo, Se, Cl, and other trace metals in tailings was greater than in a surface soil from a uranium mining area. Significant differences in nutrient and contaminant contents in aboveground biomass were found between species.     

A serologic survey of a population of Georgia dogs for Brucella canis and an evaluation of the slide agglutination test.

In a serologic survey of stray and pet dog populations of Georgia, serums were screened for Brucella canis antibodies, using the slide agglutination test. If results were positive, B canis antibody titers were determined, using the standard tube agglutination test. The stray dogs had significantly (P less than 0.01) higher titers than did the pet dogs. The reactor rate was 58% higher for the slide agglutination test than for the tube agglutination test. The manufacturer's evaluation of the slide agglutination test was based on a comparison of the serologic results of that test with those of the tube agglutination test, using a comparative method that permitted the results to be interpreted as 99% agreement between the 2 tests. Reevaluation of the manufacturer's data by a different method indicated that the slide agglutination test is very accurate when the results are negative (99.7% specific) but less so when the results are positive (62.5% sensitive).     

The role of rodents and other wildlife in the epidemiology of swine toxoplasmosis

Two swine production units and their contiguous wildlife populations were used for this study. These herds were located 7 miles apart in the major swine producing area of south central Georgia. Herd A had a Toxoplasma gondii antibody prevalence of 27.6% in all ages of swine sampled, with an increased incidence of 13.6% over a 5-month period. This herd was maintained under a semi-range condition. The swine in Herd B were maintained exclusively in concrete floored, enclosed buildings. This herd had a 0.85% T. gondii prevalence. Rodents and a few other wildlife and domestic species were trapped in or around both herds. These animals were examined for Toxoplasma antibodies using the same test procedure utilized for swine sera, the indirect immunofluorescent (IIF) test. Additionally, rodent tissues were homogenized and suspensions prepared for interperitoneal (I/P) inoculation into CF₁ laboratory mice.Rodents and wildlife species examined were: Mus musculus, Peromyscus leucopus, Rattus norvegicus, Sigmodon hispidus, Procyon lotor, and Didelphis marsupalis. Feral and domestic animals other than swine that also were tested for the presence of T. gondii antibodies included two cats, two horses, and a dog. The overall prevalence of T. gondii antibodies in all non-porcine species examined was 67% for those animals in and around the premises of Herd A, and 63% for those in and around Herd B.Toxoplasma infectivity of rodents whose tissues were processed and inoculated into laboratory mice correlated well with the results of the IIF test on the serum of these wild rodents. No tachyzoites of T. gondii were found in the peritoneal exudate of laboratory mice post I/P inoculation with wild rodent tissue, with one exception.While there was no significant difference in Toxoplasma infectivity in non-porcine species on these two premises, management practices appeared to be the determining factor in swine infection with T. gondii. Excluding wildlife precluded infection.     

Neurofibrosarcoma and leiomyosarcoma in slaughterhouse broilers

Two uncommon neoplastic lesions--a neurofibrosarcoma and a leiomyosarcoma--were found in 7-week-old slaughterhouse chickens. Grossly, the neoplasms both appeared as locally extensive, nodular lesions that displaced the mesentery and abdominal viscera. Histologically, these tumors were anaplastic and invasive into the surrounding tissues.     

Frequency of Salmonella enteritidis and other salmonellae in the ceca of spent hens at time of slaughter.

A study was conducted to determine the frequency of Salmonella enteritidis (SE) and other Salmonella serovars in the cecal contents of spent laying hens at a hen-processing plant in the southeastern United States over a 4 1/2-month period, from October 1990 through February 1991. A total of 1920 pooled cecal samples (three ceca per sample) from 38 flocks representing 23 producers were obtained and tested for the presence of SE and other Salmonella serovars. A total of 359 samples (18.7%) from 37 of the 38 flocks (97.4%) showed characteristic reactions for salmonellae on triple sugar iron agar (TSIA) slants. Twenty-nine of the 359 Salmonella-positive samples (8.1%) were Group D-positive, all of which were found to be SE on further serotyping. The SE-positive samples were from seven of the 38 flocks (18.4%); four flocks originated from the USDA/APHIS-designated Northern Region of the United States, and three were from the Southeastern Region. Serotyping of the 330 TSIA-positive Group-D negative Salmonella revealed 37 different serovars. S. heidelberg, the predominant serovar, was identified in 49.1% of these isolates.     

Effects of vaccine route and dosage on protection from rabies after intracerebral challenge in mice

OBJECTIVE: To evaluate the effect of various routes of administration and number of doses of 3 commercially produced rabies vaccines on serum antibody responses and protection in mice challenged by intracerebral injection with fixed-strain rabies virus. ANIMALS: 2,213 mice. PROCEDURE: Inactivated, adjuvanted rabies vaccines were administered to mice in either 2, 1, or 0 (control) doses via IP, IM, and SC routes, and mice were challenged intracerebrally with fixed-strain rabies virus. RESULTS: Vaccination route and dose number significantly influenced serum antibody responses and protection from rabies virus challenge, independent of vaccine strain origin and mouse strain, although mouse age significantly affected results. Extended challenge studies revealed that IM vaccination of mice resulted in the highest serum neutralizing antibody responses and protection levels equivalent to IP vaccination. Even multiple doses administered SC (a vaccination route used in dogs) resulted in poor serum anti-rabies neutralizing antibody responses in mice and were far less protective than other routes. CONCLUSIONS AND CLINICAL RELEVANCE: Findings suggest possible improvements for the current rabies vaccine potency test in mice by using 1 dose, the IM route, and a delayed time of challenge. These modifications would more closely model vaccination practices in target species and yield more accurate information regarding primary immunogenicity of a vaccine.     

Coxiella burnetii (Q fever) in Rattus norvegicus and Rattus rattus at livestock farms and urban locations in the Netherlands; could Rattus spp. represent reservoirs for (re)introduction?

The Q fever outbreak in the Netherlands in 2007-2010 prompted government interventions to reduce the human incidence by reduction of Q fever shedding at dairy goat farms. Mandatory hygiene measures were taken, including the control of animal reservoirs. It has been postulated that brown rats, through their commensal nature, form an important factor in the persistent dissemination of endemic circulating Coxiella burnetii in nature to domestic animals, livestock and humans. Here, the occurrence of C. burnetii in rats captured at different types of location during the Q fever outbreak in the Netherlands, viz. urban areas, nature areas and various types of farm has been determined. This is a first step towards the elucidation of the reservoir status of rats in veterinary and human Q fever epidemiology. C. burnetii DNA was detected in the spleen of 4.9% of the brown rats (Rattus norvegicus) and 3.0% of the black rats (Rattus rattus). Evidence for C. burnetii infection was also found in liver, kidney, lung and intestinal tissue but not in heart, brain and pancreas. C. burnetii IgGs were detected in 15.8% of the brown rats. Positive rats were collected at goat, pig, cattle and poultry farms, and urban locations; including locations outside the designated 5km "increased-risk" zones around bulk milk positive goat farms. The percentage of rat-positive locations was the highest for goat farms (50%) and cattle farms (14.3%). The presence of actively infected rats outside the lambing season and at multiple environmental settings including urban locations might suggest that rats are not merely a spill-over host due to infection by a contaminated environment but might represent true reservoirs, capable of independent maintenance of C. burnetii infection cycles and thereby contributing to spread and transmission of the pathogen. If frequent (re)introduction of C. burnetii to small ruminant farms can be caused by rats as maintenance reservoirs, mandatory wildlife control and lifelong vaccination of herds will be necessary.