Ecology and epidemiology of raccoon rabies.

Two areas of the United States presently are experiencing epizootics of raccoon rabies, which have been followed by the development of an enzootic state. These include four southeastern and five mid-Atlantic states. Information was obtained from 1,610 raccoons submitted for rabies testing in four of the affected mid-Atlantic states during 1982 and 1983 and from 798 raccoons from Virginia during 1984 and 1985. Analysis of the two sets of data provided an opportunity to characterize certain aspects of the epizootic. Raccoons collected during the day or at dusk and those that behaved abnormally were more likely to be rabid. Many human exposures to raccoons were preventable or may not have necessitated treatment. Eight (3%) of 291 serum samples from raccoons in an epizootic area had titers of antibody to rabies virus (complete neutralization) of greater than or equal to 1:25. Field trials of baiting systems incorporating an oral raccoon rabies vaccine are being conducted in Virginia, Washington, D.C., and Pennsylvania.

Antibodies to arboviruses in an Alaskan population at occupational risk of infection.

A total of 435 United States Geological Survey and United States Forest Service workers in Alaska were studied for serologic evidence of past infections with four arboviruses known or suspected to be human pathogens. Of the personnel tested, 36 (8.3%) had the neutralizing antibody to Jamestown Canyon but not snowshoe hare virus, 6 (1.4%) had the antibody to snowshoe hare but not Jamestown Canyon virus, 53 (12.2%) had the antibody to both viruses, 17 (3.9%) had the antibody to Northway virus, and 15 (3.4%) had the antibody to Klamath virus. The indices most significantly correlated with presence of the Jamestown Canyon and snowshoe hare antibodies were the amount of fieldwork (p less than 0.001 for both antibodies) and the duration of employment by the agencies (p less than 0.0001 for Jamestown Canyon and 0.004 for snowshoe hare). The antibody to the four arboviruses also correlated strongly with a history of travel in certain remote or wilderness areas in Alaska (p values ranged from less than 0.001 to 0.086).

Wildlife rabies: overview of ecology and epidemiology.

One area of increasing importance to rabies research is cooperation between organizations: industry and government, academia and government, and various local and national levels of government. The need for cooperation between countries is also emphasized. Such cooperation could provide more effective and economical rabies control.

Descriptive epidemiology from an epizootic of raccoon rabies in the Middle Atlantic States, 1982-1983.

During 1982 and 1983, the Centers for Disease Control and cooperating Middle Atlantic States and local health departments collected data on 1,610 raccoons that were submitted for rabies testing and on 133 persons who received rabies postexposure prophylaxis as a result of exposure to wild animals. Raccoons were found most commonly in yards and residential areas. Raccoons that were killed by private citizens, animal-control personnel, or dogs had the highest positivity rate (70%), and those that were trapped had the lowest (9%). Raccoons that were found during the day or that exhibited abnormal behavior and those that had interacted with a domestic animal were more likely to be rabid. Examination of the data on human exposure disclosed that many exposures could have been avoided or prevented. Almost 50% of postexposure treatments were administered to persons whose actual risk of exposure was low or nonexistent.

Preexposure immunization with intradermal human diploid cell rabies vaccine. Risks and benefits of primary and booster vaccination.

Intradermal human diploid cell rabies vaccine (ID HDCV) was licensed for preexposure use in the United States on May 30, 1986. We studied the safety and efficacy of this newly approved route and dose of administration. Serologic results were available from 112 (90%) of the 124 persons who participated in an HDCV low-dose preexposure study in which five different ID, intramuscular (IM), and subcutaneous primary immunization regimens were administered. Three 1.0-mL IM doses of vaccine resulted in titers similar to those from three 0.1-mL ID doses when compared 49 days, one year, and two years after primary immunization. Uniformly high postbooster titers occurred in all five groups when ID boosters were administered at one year or two years. Adverse reactions were similar following both ID and IM vaccination. Although ID HDCV can be a cost-effective substitute for IM vaccine, excessive use of unnecessary preexposure booster doses by any route may be inadvisable because of systemic allergic reactions. In addition, poor immune responses to HDCV have been documented in persons vaccinated in some developing countries. This may limit the use of low-dose regimens in some places.

Demonstration of antigenic variation among rabies virus isolates by using monoclonal antibodies to nucleocapsid proteins.

Rabies virus isolates from terrestrial animals in six areas of the United States were examined with a panel of monoclonal antibodies to nucleocapsid proteins. Characteristic differences in immunofluorescence reactions permitted the formation of four antigenically distinct reaction groups from the 231 isolates tested. The geographic distribution of these groups corresponded well with separate rabies enzootic areas recognized by surveillance of sylvatic rabies in the United States. Distinctive reaction patterns were also identified for viral proteins from four infected bat species, and identical patterns were found in eight isolated cases of rabies in terrestrial animals. These findings suggest that monoclonal antibodies can be used to study the prevalence, distribution, and transmission of rabies among wildlife species.

Rabies in rodents and lagomorphs in the United States, 1971-1984: increased cases in the woodchuck (Marmota monax) in mid-Atlantic states.

A review of surveillance data on animal rabies from the Centers for Disease Control revealed 104 cases of rabies in rodents and lagomorphs for 1971 through 1984 in the United States; 80% of these were reported between 1980 and 1984. Woodchucks (Marmota monax) accounted for 64% of the cases. Most of the cases of rabies in woodchucks were associated with an epizootic of rabies in raccoons (Procyon lotor) in the mid-Atlantic states. In rabies endemic areas, humans exposed to woodchucks should receive rabies postexposure prophylaxis if the animal is not available for testing. The decision to administer postexposure prophylaxis to humans exposed to other rodents and lagomorphs should take into consideration the epidemiology of rabies in the exposing species.

Surveillance of Rocky Mountain spotted fever in the United States, 1981-1983.

Surveillance of Rocky Mountain spotted fever (RMSF) in the United States has revealed a stable incidence of the disease from 1981 to 1983, with a median of 0.48 cases/100,000 population per year (range, 0.42-0.52). During this three-year period an increase in both the number and the percentage of total cases reported from the West South Central states was observed when compared with previous three-year periods. An expanded case report form, which was introduced in 1981 for use by state health departments, was received for 2,850 (87%) of the 3,294 cases reported in 1981-1983. Of these 2850 cases, 1375 (48%) were laboratory confirmed. Death from RMSF was more common in persons greater than or equal to 30 years of age (case-fatality ratio of 8.4%) than in persons less than 30 years (2.2%, P less than .001). Fatality was also associated with failure to obtain a history of a tick bite within 14 days before onset of illness (P less than .05) and with lack of treatment with tetracycline or chloramphenicol (P less than .01).

Human leukocyte interferon administration to patients with symptomatic and suspected rabies.

Body fluids and brain tissue from rabid human patients have demonstrated only low titers of interferon. Therefore, pharmacokinetic studies of systemically administered and locally injected leukocyte interferon were performed in 2 North American patients with suspected rabies who showed no clinically important side effects of this therapy. Similar therapy was given to 5 patients with symptomatic rabies in Europe and America. Although no prolongation of the clinical course was seen in 3 patients given high-dose intraventricular and systemic therapy, treatment was not initiated until between 8 and 14 days after symptoms were seen. The intraventricular dosage regimen produced cerebrospinal fluid levels that appeared to fall progressively over the 24 hours after injection and demonstrated good but somewhat delayed distribution into the lumbar sac. Titers produced by this therapy were 30- to 10,000-fold higher than those normally observed in this infection, however. In the patients treated at the highest dosage, a diminished and delayed antirabies neutralizing antibody titer was observed, probably a result of the administration of the exogenous interferon.

Antigenic characteristics of isolates associated with a new epizootic of raccoon rabies in the United States.

A panel of 23 monoclonal antibodies to the nucleocapsid protein of rabies virus was used to study the antigenic character of isolates of rabies virus from raccoons in the mid-Atlantic region of the United States. Comparison of the reaction pattern of these isolates with that of isolates of rabies virus collected from areas of major rabies outbreaks (skunk rabies in the midwestern United States, fox rabies in the northeastern United States, and raccoon rabies in the southeastern United States) suggests that this new epizootic originated with the transportation of rabid raccoons from the southeastern United States.

Human rabies in the United States, 1960 to 1979: epidemiology, diagnosis, and prevention.

Thirty-eight cases of human rabies occurred in the United States and its territories from 1960 to 1979. The major source of exposure to rabies has changed from indigenous dogs and cats in the 1940s and 1950s to wild carnivores and bats (11 of the 27 cases with known exposures); unusual exposures (3 cases) and exposures in a foreign country (7 cases) have also become more important. No exposure could be identified for 6 of the 38 cases. Two patients received optimal prophylaxis, 14 suboptimal, and 22 no prophylaxis after exposure. Some cases might have been prevented by an increased awareness of the risks and treatment for exposure to rabies, and use of the new rabies vaccines. The diagnosis was often made late in the clinical course including after death in 8 cases. This delay, in part, resulted from the diversity in the clinical presentation. Rabies should be considered in any case of encephalitis or myelitis. Laboratory confirmation of the diagnosis was often delayed. Testing for serum antibodies was the most reliable test in unvaccinated patients, and isolation of virus was the test most likely to be positive early in the illness.

Nosocomial rabies: investigation of contacts of human rabies cases associated with a corneal transplant.

In October 1978 in Boise, Idaho, a woman died of rabies after receiving a corneal transplant from a man, who in retrospect was also found to have died of rabies. Investigation of 203 contacts of these two patients identified 94 who were felt to have had sufficient risk of exposure to justify being given rabies post-exposure prophylaxis. Nurses, physicians, respiratory therapists, and family members were at greatest risk. We discuss the problems encountered in determining risk of exposure for contacts of humans with rabies.

Surveillance of Rocky Mountain spotted fever, United States, 1981-1983.

The increase in the incidence of RMSF observed in the 1970s appears to have plateaued at a median of 0.49 cases/100,000 for the 6-year period 1978-1983. In 1981-1983, for the first time, Oklahoma had the highest incidence of RMSF in the United States (4.10 cases/100,000/year); increased numbers of cases were also reported from two of the other three West South Central states-Texas and Arkansas. Texas, which reported 217 cases in the 3-year period, had an average incidence of 0.47 cases/100,000/year. This apparent regional increase in RMSF activity may reflect multiple factors, including increased recognition and reporting of cases and environmental factors that may be associated with a true increase in RMSF. Simultaneously, a decrease in the number of cases reported and in the incidence of RMSF have been observed in the South Atlantic states, although these states still account for most (51%) of the cases in the United States. The slight decrease in the case-fatality ratio observed over the last 9 years is unexplained. It may reflect increased awareness of RMSF and result in appropriate and timely treatment. The increasing number and percentage of cases that are laboratory confirmed suggest that the more sensitive and specific laboratory tests now required for serologic confirmation are being more widely used and are contributing to an increased accuracy of reporting of RMSF in this country.(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory illness in conference participants following exposure to rug shampoo.

Persons participating in a conference in a major city motel experienced transient mild respiratory illness associated with their presence in the motel conference rooms. The illness was characterized by coughing, sneezing, sore throat, headache, eye irritation, and other symptoms of exposure to a respiratory irritant. Investigation incriminated a chemical shampoo used to clean the conference room rugs approximately one week earlier. Repeated cleaning of the rugs to remove excess cleaning compound eliminated the problem. Excessive application of the shampoo, coupled with a poorly ventilated environment, apparently produced a chemical concentration sufficient to cause clinical illness.

Q fever control measures: recommendations for research facilities using sheep.

Q fever (Query Fever) is a zoonosis caused by the rickettsia Coxiella burnetii. domestic ungulates such as sheep, cattle, and goats serve as the reservoir of infection for humans and shed the desiccation-resistant organism in urine, feces, milk, and especially in birth products. In humans the illness is generally mild; however, Q fever hepatitis is often seen and Q fever endocarditis is an uncommon, but frequently fatal complication. Q fever long has been recognized as an occupational hazard among persons working with animals or animal products, and in laboratories working with C. burnetii. Recently, Q fever outbreaks have occurred in medical research facilities using sheep as research animals. Recommendations are presented for reducing the risk of exposure to Q fever in persons not working with sheep in research facilities that use sheep. In addition, recommendations are presented for reducing the risk of infection in persons who work with sheep in research facilities.

Infection of Syrian hamsters with lymphocytic choriomeningitis virus: comparison of detection methods.

The prevention of hamster-associated outbreaks of lymphocytic choriomeningitis virus infection in human beings requires rapid and reliable testing of large numbers of hamsters for the infection. To select the most effective test, the antibody response of infected hamsters was determined by the indirect fluorescent antibody and complement-fixation techniques. The indirect fluorescent antibody technique required less than 2 hours to complete, was the first to become positive after infection, and remained positive for at least several months. Infection in hamsters was also readily detected by the inoculation of mice with infected hamster tissues; virus could be isolated from several organs as early as postinoculation day (PID) 3, and all organs tested contained high concentrations of virus by PID 5. After PID 40, virus was detectable only in the kidney; this organ remained positive for over 3 months.