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The epidemiology of rabies in the United States has changed dramatically over the past few decades. Greater than 90% of all animal rabies cases reported annually to the Centers for Disease Control and Prevention now occur in wildlife, whereas before 1960 the majority were domestic animals. The principal rabies reservoirs today are wild carnivores and bats, infected with many different types of rabies virus variants. Annual reporting of human deaths have fallen from more than 100 at the turn of the century to one to six per year, despite major outbreaks of animal rabies in several distinct geographic areas. Most recent human rabies cases acquired in the United States are the result of infection with rabies virus variants associated with bats, although the exact incident leading to exposure has been difficult to define. Many recent deaths have occurred in persons who failed to seek post-exposure treatment, presumably because they did not recognize a risk in the animal contact leading to the infection or failed to recognize that contact had occurred. Although these human rabies deaths are rare, estimated public health costs associated with disease detection, prevention, and control have risen, exceeding millions of dollars each year.

Since 1993, three novel hantaviruses have been identified from the United States of which at least two can cause a severe respiratory disease termed hantavirus pulmonary syndrome (HPS). Rodent reservoirs have been identified for two viruses; Peromyscus maniculatus is the primary host of Muerto Canyon Virus (MCV) in the western United States and genetic analyses have implicated Sigmodon hispidus as the probable host of a hantavirus in Florida. Of 813 P. maniculatus tested in the southwestern United States 30.4% were infected; 12 of 90 (13.3 %) S. hispidus from Florida were infected. The S. hispidus-associated virus has not been isolated in cell culture and its etiologic role in human disease is unproven. The rodent reservoir for the third virus, associated with a fatal case of HPS in Louisiana, is unknown. These viruses are genetically distinct from their old world relatives, and cause a different spectrum of human disease. In the United States, respiratory disease is prominent while renal disease is most often reported from Eurasia. As yet the number of HPS cases occurring annually in the United States is unknown, but since the syndrome was identified in May, 1993, 50 cases have been reported from 15 states with an overall mortality ratio of 60%. The risk to groups occupationally exposed to rodents is being investigated.

Since 1981, an epizootic of raccoon rabies has spread throughout the eastern United States. A concomitant increase in reported rabies cases in skunks has raised concerns that an independent maintenance [...]

In March 2002, typhus fever was diagnosed in two patients residing in West Virginia and Georgia. Both patients were hospitalized with severe febrile illnesses, and both had been recently exposed [...]

Mathematical models have been developed to explore the population dynamics of viral diseases among wildlife. However, assessing the predictions stemming from these models with wildlife databases adequate in size and temporal duration is uncommon. An epizootic of raccoon rabies that began in the mid-Atlantic region of the United States in the late 1970s has developed into one of the largest and most extensive in the history of wildlife rabies. We analyzed the dynamics of local epizootics at the county level by examining a database spanning more than 20 years and including 35,387 rabid raccoons. The size, number, and periodicity of rabies epizootics among raccoons were compared with predictions derived from a susceptible, exposed, infectious, and recovered model of raccoon rabies [Coyne, J., Smith, G. & McAllister, F. E. (1989) Am. J. Vet. Res. 50, 2148-2154]. After our methods for defining epizootics were applied to solutions of the model, the time series revealed recurrent epizootics in some counties, with a median first epizootic period of 48 months. Successive epizootics declined in size and the epizootic period progressively decreased. Our reanalysis of the model predicted the initial-epizootic period of 4-5 years, with a progressive dampening of epizootic size and progressive decrease in epizootic period. The best quantitative agreement between data and model assumed low levels of immunity (1-5%) within raccoon populations, suggesting that raccoons develop little or no rabies immune class. These results encourage the use of data obtained through wildlife surveillance in assessing and refining epidemic models for wildlife diseases.

ABSTRACT: In an in vitro model, 20 condoms containing 0.9 mL of 6.6% (vol/vol) nonoxynol 9 and ten condoms without nonoxynol 9 were tested as physical and chemical barriers against human immunodeficiency virus (HIV). Each condom was mounted on a hollow dildo and placed in a glass cylinder. The HIV inoculum and HIV-free medium were placed on opposite sites of the condom. Intercourse was simulated by pumping the dildo up and down in the cylinder before and after deliberate rupture of the condom. Samples for HIV culture were taken from outside and inside the condom, before and after rupture. After rupture of nonoxynol 9-containing condoms, an outside nonoxynol 9 concentration of 0.25% was reached. No condom without nonoxynol 9 leaked HIV before rupture, but after rupture HIV could be detected in medium outside of seven of ten condoms tested. In none of 20 nonoxynol 9-containing condoms could HIV be detected in outside medium after rupture. Thus, undamaged condoms provide an effective physical barrier against HIV, and nonoxynol 9 may provide an effective chemical barrier as well.