USE OF A POINT OF CARE TEST TO DETERMINE THE PREVALENCE OF ANTIBODIES TO TOXOPLASMA GONDII IN BLACK BEARS FROM NORTH CAROLINA AND PENNSYLVANIA.

Toxoplasma gondii is an important protozoan parasite of humans and animals throughout the world. Black bears are among the animals with the highest seroprevalence of T. gondii in the United States. A rapid point of care (POC) test is commercially available to detect antibodies to T. gondii in humans. We evaluated the utility of the POC test to detect anti-T. gondii antibodies in 100 wild black bears from North Carolina (n = 50) and Pennsylvania (n = 50). In a blind study, sera were tested by the POC test, and results were compared to the modified agglutination test (MAT). Overall, anti-T. gondii antibodies were detected in 76% (76/100) black bears by both MAT and POC tests. One false positive and one false negative result in the POC test were obtained in bears from Pennsylvania. The sensitivity and specificity of the POC test were both 99% when compared to the MAT. Results from our study indicate the POC test could be a useful screening tool for serological surveillance of T. gondii in black bears.

GAMOGONY OF SARCOCYSTIS STRIXI IN MAMMALIAN CELL CULTURES.

We are interested in the disease ecology of Sarcocystis species that infect birds of prey as definitive and intermediate hosts. The present study was done to test our hypothesis that a laboratory model can be developed for sarcocystis infection in mammals using gamma interferon gene knockout (KO) mice as a source of Sarcocystis strixi bradyzoites and mammalian cell cultures as a source of sporulated S. strixi oocysts. Sporocysts of S. strixi from a naturally infected barred owl (Strix varia) were fed to KO mice to produce sarcocysts, and the enclosed bradyzoites were obtained by acid-pepsin digestion of abdominal and thigh muscles. Bradyzoites, metrocytes, and an unusual spherical stage were seen in digest before the inoculation of host cells. The spherical stages stained dark with Giemsa stain, but no nucleus was observed, and they were seen free and associated with the concave portion of some bradyzoites. Examination of infected cell cultures demonstrated that macrogamonts and microgamonts were present at 24 hr post-inoculation. Since sporulated oocysts were not observed, we had to reject our current hypothesis.

Prevalence of Sarcocysts in the Muscles of Raptors from a Rehabilitation Center in North Carolina.

The life cycle of Sarcocystis species is heteroxenous (2-host), with carnivores being the definitive host and herbivores serving as intermediate hosts in predator-prey relationships. Raptors (eagles, hawks, falcons, and owls) are apex predators and are not consumed routinely by other carnivores, making the occurrence of sarcocysts in their muscles unusual. Recent reports of sarcocysts in eagles and owls with Sarcocystis encephalitis suggests that this condition may be becoming more frequent, and Sarcocystis falcatula has been implicated as the agent of encephalitis in golden ( Aquila chrysaetos) and bald eagles ( Haliaeetus leucocephalus) as well as great horned owls ( Bubo virginianus). The present study was done to determine the prevalence of sarcocysts of Sarcocystis species in the muscles of raptors from the southeastern United States. Pectoral and heart muscle from 204 raptor patients from the Carolina Raptor Center, Huntersville, North Carolina were tested for the presence of Sarcocystis species using histology. Only a few sarcocysts were seen in sections of pectoral muscle from 39 of 204 raptors (19.1%) and heart muscle from 9 that also had sarcocysts in their pectoral muscle. Two structural types of sarcocysts, thin-walled (1 µm; 62%) or thick-walled (>2 µm, 38%), were seen. Statistical analysis of raptor age and gender was done by Fisher's exact test on samples from raptors with 20 or more samples per group. The prevalence of sarcocysts by age (2 yr or more) was significant for red-shouldered hawks ( Buteo lineatus) ( P = 0.022) and Cooper's hawks ( Accipiter cooperii) ( P = 0.028). Sarcocyst prevalence in male raptors from these groups evaluated statistically were always less than in females. Prevalence in female red-tailed hawks ( Buteo jamaicensis) (42.1%) was significantly greater than in males (6.7%) using Fisher's exact test ( P = 0.047). Examination of case histories from the 39 sarcocyst-positive raptors did not reveal an association with sarcocysts in raptor pectoral or heart muscle and in a diagnosis of encephalitis. Additional studies are needed to determine the epidemiology and relationships of Sarcocystis spp. that use raptors as intermediate hosts and the importance of Sarcocystis spp. in the overall wellbeing of raptors in their natural environments.

Prevalence of antibodies against visceralizing Leishmania spp. in brown rats from Grenada, West Indies.

BACKGROUND AND AIM: Leishmania spp. are known to cause disease in man and animals. Rats are considered important reservoir hosts and transmission takes place through the bite of female sand fly, Phlebotomus spp. To the best of our knowledge, there is no published information on Leishmania infection in rats in Grenada. This study was conducted to estimate the antibodies for visceralizing Leishmania spp. (VL) in rats (Rattus norvegicus) from Grenada. MATERIALS AND METHODS: A total of 146 brown rats (R. norvegicus) were trapped live from two parishes (St. George and St. David) in Grenada. Following anesthesia, blood was collected from the heart through thoracic puncture. The serum was collected after the centrifugation of blood. Serum was tested for antibodies to VL. with a commercially available immunochromatographic dipstick test which is licensed for use in animals and humans. RESULTS: The seroprevalence of antibodies against Leishmania spp. was found in 34 of 146 rats (23.3%; CI 95% from 16.70 to 30.99). No significant differences were found between sexes and young or adults. The prevalence between parishes (St. George and St. David) was also not significant. CONCLUSION: The results show that rats (R. norvegicus) in Grenada are exposed to Leishmania spp. The rats could play an important role in the transmission of leishmaniasis to humans and other animals in Grenada.

Flotation of Toxocara canis Eggs in Commercial Bleach and Effects of Bleach Treatment Times on Larval Development in These Eggs.

Toxocara canis is a common intestinal nematode of young dogs. Puppies contaminate the environment with large numbers of eggs that can embryonate and become infective in less than a month. Embryonated eggs are infectious for humans and other paratenic hosts. Most T. canis infections in humans are asymptomatic; however, migration of T. canis larvae in the eye and in the central nervous system can result in vision loss, blindness, and even death. The eggs of T. canis are highly resistant to harsh environmental conditions and routinely used chemical disinfectants. The objective of this study was to evaluate the effects of full-strength commercial bleach (5.25% sodium hypochlorite solution) treatment on development of T. canis eggs and to report our serendipitous finding that T. canis eggs in dog feces can float in passive fecal flotation tests using bleach. We also demonstrated that T. canis eggs could be identified using the McMaster's fecal eggs counting test using 100% bleach. Toxocara canis eggs collected from the feces of naturally infected 4-8 wk old puppies were treated with full-strength bleach (5.25% sodium hypochlorite solution) for 15 min, 30 min, 60 min, and 120 min; washed free of bleach smell by centrifugation; and resuspended in 0.1 N sulfuric acid solution to undergo larval development at room temperature for 18 days after exposure to bleach. Motile larvae were observed in T. canis eggs in all groups treated for 15-120 min and eggs continuously exposed to bleach for 18 days. Our results indicate that bleach may not be an appropriate disinfectant for dog kennels, cages, or laboratory utensils and work surfaces. Toxocara canis eggs are resistant to bleach treatment and continue to pose a risk for canine and human infections. Further study is needed to find the most appropriate methods for disinfection and removal of eggs to reduce the risk of transmission of this parasite.