Prevention of the spread of rabies to wildlife by oral vaccination of raccoons in Massachusetts.

OBJECTIVE: To evaluate the use of bait containing rabies vaccine to create a barrier of rabies-vaccinated raccoons in Massachusetts and to determine the effectiveness of various bait distribution strategies in halting the spread of rabies. DESIGN: Prospective study. SAMPLE POPULATION: Free-ranging raccoons. PROCEDURE: Baits were distributed twice yearly in a 207-km2 (80-mi2) area in the vicinity of the Cape Cod Canal. Bait density and distribution strategy varied among 3 treatment areas. Raccoons were caught in live traps after bait distribution and anesthetized; blood samples were obtained to measure serum antibody titers to rabies virus. Vaccination rates were determined by the percentage of captured raccoons with antibody titers to rabies virus > or = 1:5. In addition, raccoons with clinical signs of illness inside the vaccination zone and adjacent areas were euthanatized and submitted for rabies testing. RESULTS: The percentage of vaccinated raccoons differed significantly among the following 3 areas with various bait densities: high-density area with uniform bait distribution (103 baits/km2 [267 baits/mi2]) = 37%; low-density area with additional targeted bait distribution (93 baits/km2 [240 baits/mi2]) = 67%; and, high-density area with additional targeted bait distribution (135 baits/km2 [350 baits/mi2]) = 77%. Nineteen animals with rabies (15 raccoons, 3 skunks, 1 cat) were reported in the area just outside of the vaccination zone, but only 1 raccoon with rabies was reported from inside the vaccination zone. CLINICAL IMPLICATIONS: In this suburban study area, an approximate vaccination rate of 63% was sufficient to halt the spread of rabies in free-ranging raccoons. Compared with uniform bait distribution, targeting raccoon habitats increased vaccination rates.

A dose response study of hepatitis A vaccine in healthy adults who are > or = 30 years old and weigh > or = 77 kg.

The dose response relationship of 25-, 50-, and 100-U doses of an inactivated hepatitis A vaccine was examined in 358-seronegative volunteers in a 2-dose schedule. The 50-U and 100-U groups had statistically significantly higher seroconversion rates than the 25-U group at weeks 2, 4, 8, and 24. Seroconversion was statistically significantly greater for the 100-U compared with the 25- and 50-U doses 2 weeks after the first injection but was not significantly different by 4 weeks after the first injection in the 50- and 100-U dose groups. After 2 injections, all subjects in all groups seroconverted. The vaccine was well tolerated at all dosage levels.

Antibodies to Borrelia burgdorferi in New England horses: serologic survey.

Twelve of 50 randomly selected horses from areas endemic for Borrelia burgdorferi had indirect fluorescent antibody titers of 1:8 to 1:2,048 against B burgdorferi. One of 50 horses from nonendemic areas had a titer of 1:8. This difference in the number of horses seropositive for B burgdorferi (P less than 0.002) and our finding that seropositive horses did not have agglutinating antibodies against potentially cross-reacting Leptospira spp indicated that horses in endemic areas were exposed to B burgdorferi and that the spirochete induced an antibody response in the horses.

Fatal pancarditis in a patient with coexistent Lyme disease and babesiosis. Demonstration of spirochetes in the myocardium.

A 66-year-old man developed fever, chills, myalgias, three erythematous skin lesions, and transient left eyelid lag. Because of persistent fever, he was hospitalized 4 weeks after the onset of disease; a peripheral blood smear showed Babesia microti in 3% of his erythrocytes. Eighteen hours later, he died unexpectedly. Autopsy showed pancarditis with a diffuse lymphoplasmacytic infiltrate, and spirochetes were found in the myocardium. Antibody titers to both the Lyme disease spirochete Borrelia burgdorferi and Babesia microti were elevated. The finding of spirochetes in the myocardium and the elevated antibody titers to Borrelia burgdorferi suggest that the patient died from cardiac involvement of Lyme disease.

Ocular toxocariasis presenting as leukocoria in a patient with low ELISA titer to Toxocara canis.

A 4-year-old white female presented with leukocoria of the right eye. White punctate lesions were observed posterior to the retrolental membrane, which suggested retinoblastoma of some examiners. A full history, physical examination, ultrasonography, and CT scan failed to rule the diagnosis of retinoblastoma in or out. A serum ELISA titer was 1:4, which was considered nondiagnostic. Examination of the enucleated eye revealed a midsegment of the second stage larva of Toxocara canis. The strengths and weaknesses of various diagnostic modalities used to differentiate leukocoria caused by retinoblastoma and T canis are discussed.

Visceral larva migrans and eosinophilia in an emotionally disturbed child.

Visceral larva migrans, Entamoeba coli, evidence of latent toxoplasmosis and a history of plumbism were found in an emotionally disturbed, retarded child. Patients with pica should be screened for parasitism and other diseases transmitted orally.

Eastern equine encephalitis in Massachusetts, 1957-1976. A prospective study centered upon analyses of mosquitoes.

Reappearance of eastern equine encephalitis (EEE) in Massachusetts residents in the 1970's provided an opportunity to assess the predictive value of data on rainfall, EEE in horses, and carriage of EEE virus (EEEV) by mosquitoes, factors which had been studied annually since the last EEE outbreak in 1955-1956. The cycle of multiple cases during 1973-1975 started in a second consecutive year of rainfall that exceeded the annual mean by more than 20 cm, conditions recapitulating the 1955-1956 experience. In 1973, widespread EEE fatalities in horses presaged human cases, another recapitulation of the 1955-1956 experience. However, in 1974, when horses were immunized extensively, no equine cases were seen even though three human fatalities occurred. An unseasonably early appearance of EEEV in mosquitoes was the only basis upon which the threat to humans could have been recognized. These changes in the recognition and distribution of EEEV activity from season to season illustrate the difficulty in making rational decisions regarding widespread aerial insecticide applications for mosquito control.

Experimental alimentary infection of anole lizards (Anolis carolinensis) with Mycobacterium ulcerans.

Pathogenic Mycobacterium ulcerans were recovered from the stool of anole lizards up to 11 days after inoculation by stomach tube. M. ulcerans was isolated from the liver of 3 of 20 lizards and acid fast bacteria were seen in the mucosa of intrahepatic bile ducts in 2 of these 10 weeks post-inoculation. These results provide equivocal support for our hypothesis that herpetofauna are a reservoir of infection with M. ulcerans.

Experimental infection of anole lizards (Anolis carolinensis) with Mycobacterium ulcerans by the subcutaneous route.

To test whether herpetofauna could be a laboratory model for Mycobacterium ulcerans, 21 anole lizards were inoculated subcutaneously with viable M. ulcerans, 21 with autoclaved organisms, and 14 with an aqueous solution of 0.01% Tween 80. M. ulcerans was recovered in culture from the slowly progressive lesions which developed at the inoculation site in lizards receiving the viable bacteria. Progressive lesions did not occur in the two control groups. Three patterns of inflammatory response to viable M. ulcerans were observed: 14 lizards developed a diffuse, granulomatous reaction in which acid fast bacilli (AFB) were predominantly intracellular; 1 developed focal, encapsulated granulomas; 5 developed a diffuse, necrotizing granulomatous response in which most AFB were extracellular--similar to the characteristic lesion found in human infections.