Emergence of eastern encephalitis in Massachusetts.

The 20th century emergence in Massachusetts of zoonotic eastern encephalitis was interpreted in terms of recorded environmental change. The main mosquito vector of the infection, Cs. melanura, appears to have been scarce in eastern North America before the 1930s.

The emergence of Lyme disease and human babesiosis in a changing environment.

This pattern of spread of Lyme disease and its vectors in the northeastern United States and Europe derives from the recent proliferation of deer, and the abundance of deer derives from the process of reforestation now taking place throughout the North Temperate Zone of the world. Residential development seems to favor small tree-enclosed meadows interspersed with strips of woodland, a "patchiness" much prized by deer, mice, and humans. As a result, increasingly large numbers of people live where risk of Lyme disease and babesiosis is intense.

Generation of inositol phosphates in bitter taste transduction.

It is probable that there is a diversity of mechanisms involved in the transduction of bitter taste. One of these mechanisms uses the second messengers, inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). Partial membrane preparations from circumvallate and foliate taste regions of mice tongues responded to the addition of known bitter taste stimuli by increasing the amount of inositol phosphates produced after 30 s incubation.

Detection of Borrelia burgdorferi DNA in museum specimens of Peromyscus leucopus.

To determine whether Borrelia burgdorferi was enzootic within the United States at the beginning of the 20th century, ear skin samples taken from museum specimens of the white-footed mouse (Peromyscus leucopus) were examined for evidence of spirochetal DNA. In total, 280 samples from mice collected between 1870 and 1919 were analyzed by a nested polymerase chain reaction protocol. Of these, 2 specimens from the vicinity of Dennis, Massachusetts, during 1894 were reproducibly positive for B.

Amplifying role of edible dormice in Lyme disease transmission in central Europe.

To determine whether the presence of edible dormice (Glis glis) amplifies the risk of human infection by the Lyme disease spirochete (Borrelia burgdorferi), the capacity of dormice as reservoir hosts was compared with that of other potential reservoirs in a central European site where risk of human infection is intense. Dormice appeared to be more heavily infested by subadult vector wood ticks (Ixodes ricinus) than were other reservoir hosts. Although their spirochete competence was similar to other reservoir hosts, field-derived dormice infected more ticks than did other rodents in the site, because nymphal ticks most readily feed on them.

Cultivation and phylogenetic characterization of a newly recognized human pathogenic protozoan.

An intraerythrocytic protozoan (WA1) recently isolated from a patient in Washington State was shown to be morphologically identical to Babesia microti but biologically and genetically distinct. Continuous growth of WA1 was established in stationary erythrocyte cultures. Hybridization of a chemiluminescent Babesia-specific DNA probe to Southern blots of restriction enzyme-digested genomic DNA showed that WA1 could be distinguished from other Babesia species that were antigenically cross-reactive (Babesia gibsoni and babesial parasites from desert bighorn sheep, Ovis canadensis nelsoni) or known to infect humans (B.

Diagnosis of babesiosis: evaluation of a serologic test for the detection of Babesia microti antibody.

To assess the possibility of standardization of a commonly used indirect immunofluorescent antibody (IFA) test for detection of Babesia microti antibody in human sera, the results from four reference laboratories were compared. Patients with babesiosis from southern New England (n = 25) and subjects with no history of babesiosis from southern New England (n = 55) and Iceland (n = 50) were enrolled in the study. Anti-Babesia antibody titers were determined in a blinded fashion by IFA test.

Transmission of the agent of Lyme disease on a subtropical island.

To determine whether the agent of Lyme disease (Borrelia burgdorferi) perpetuates on a subtropical island, we recorded prevalence of spirochetal infection in Ixodes ricinus ticks collected on Madeira Island and identified local reservoir hosts of both pathogen and vector tick. Spirochetes infect at least 1.3% of the nymphal ticks collected in a particular site.

Incorporation of body components of diverse microorganisms by larval mosquitoes.

A pulse-purge schedule of exposure to labeled microorganisms was used to compare their digestibility by larval mosquitoes. Larvae were placed for an hour in suspensions of diverse axenically grown microorganisms that had been labeled with radioactive carbon (in the form of glucose or glycine). The guts of these mosquitoes were then purged with nonlabeled Sephadex particles for 30 min, and retained radioactivity was measured.

Accelerated transmission of Lyme disease spirochetes by partially fed vector ticks.

To determine how rapidly Lyme disease spirochetes (Borrelia burgdorferi) can be transmitted by partially fed vector ticks (Ixodes dammini), attached nymphs were removed from their hosts at various intervals post-attachment and subsequently permitted to re-feed to repletion on noninfected mice. We confirm previous reports that ticks deposit Lyme disease spirochetes in the skin of their hosts mainly after 2 days of attachment. Those that have been removed from a host within this interval can reattach and commence feeding.

Topical prophylaxis for Lyme disease after tick bite in a rodent model.

To determine whether infection with the Lyme disease spirochete (Borrelia burgdorferi) can be aborted by topical application of antibiotic to the site of tick attachment, individual infected nymphal deer ticks (Ixodes dammini) were permitted to feed on the ears of mice, and various antibiotics were applied to the feeding site at intervals after the replete infecting tick had detached. Infection in each mouse was determined by serology and by xenodiagnosis at 4 weeks after the bite of the infected tick. None of these mice became infected when antibiotic was topically applied to the site of tick attachment within 2 days after the spirochete-infected ticks had detached.

Norway rats as reservoir hosts for Lyme disease spirochetes on Monhegan Island, Maine.

To determine whether the agent of Lyme disease, Borrelia burgdorferi, may be maintained in the absence of its usual white-footed mouse reservoir host, Ixodes dammini ticks from an island where mice are absent were examined. Prevalence of spirochetal infection was described for ticks removed from mammals, birds, and vegetation on Monhegan Island, Maine. Forty percent of adult I.

Protein analysis of human von Ebner saliva and a method for its collection from the foliate papillae.

The lingual serous glands of von Ebner are located close to the foliate and circumvallate papillae. Saliva secreted by these glands provides the immediate environment of the taste buds, and it has been hypothesized that it modulates taste perception. The purpose of this study was to develop a technique for collection of unstimulated and stimulated saliva from human von Ebner glands.

Protection against antigenically variable Borrelia burgdorferi conferred by recombinant vaccines.

Due to local variation in the antigenicity of the agent of Lyme disease (Borrelia burgdorferi), a vaccine derived from any one isolate of this spirochete may fail to protect against the heterogeneous population of organisms that may be present in an enzootic focus. Accordingly, we determined whether antigenically variable spirochetes delivered by naturally infected ticks, collected from a site where transmission is intense, may fail to infect mice actively immunized with recombinant glutathione transferase outer surface fusion proteins A or B (OspA and OspB). Virtually all mice vaccinated by either immunogen appeared not to become infected, as determined by culture or histopathology of their tissues.

Rapid dissemination by the agent of Lyme disease in hosts that permit fulminating infection.

We determined whether the agent of Lyme disease (Borrelia burgdorferi) disseminates more rapidly following deposition in hosts that permit fulminating infection than in hosts in which infection is relatively benign. Thus, individual infected nymphal deer ticks (Ixodes dammini) were permitted to engorge on the ears of C3H mice, and the site of attachment was excised at intervals thereafter. Infection in each mouse was determined by serology and by examining previously noninfected ticks that had engorged on these mice.

Diversionary role of hoofed game in the transmission of Lyme disease spirochetes.

To determine whether the presence of ungulates may inhibit transmission of the agent of Lyme disease (Borrelia burgdorferi) while promoting the abundance of its European vector tick (Ixodes ricinus), we compared the feeding density of subadult ticks on roe deer (Capreolus capreolus), red deer (Cervus elaphus), fallow deer (Dama dama), and wild sheep (Ovis ammon) near Berlin and in Brandenburg State, Germany. The prevalence of spirochetal infection in these ticks was compared with that in ticks swept from nearby vegetation. Spirochetes are present in nearly one-fifth of nonfed, questing nymphal and adult wood ticks in the region.

Standardization of medium for culturing Lyme disease spirochetes.

To standardize the procedure for isolating and culturing Lyme disease spirochetes, we modified the composition of the medium generally used for this purpose (BSK-II) and developed a system for its distribution. This medium contains no gelatin or agarose, and various components are used in proportions that differ from those in BSK-II. Each of the major proteinacious components was screened by substitution in samples of the complete product.

Reservoir competence of white-footed mice for Babesia microti.

Although the white-footed mouse, Peromyscus leucopus Rafinesque, has been incriminated as the main reservoir of the agent of human babesiosis, Babesia microti Franca, a quantitative demonstration of reservoir competence has not been presented. Mice captured within an intensely zoonotic site served as host for laboratory-reared larval Ixodes dammini Spielman, Clifford, Piesman, and Corwin, and the resulting nymphal ticks were assayed for evidence of salivary gland infection by the piroplasm. Solely 25% of the mice were patently parasitemic on thin blood smears, but virtually all mice infected ticks with B.

Reduced abundance of immature Ixodes dammini (Acari: Ixodidae) following incremental removal of deer.

The abundance of immature Ixodes dammini Spielman, Clifford, Piesman & Corwin was monitored for 9 yr (1983-1991) before and during the controlled, limited hunting of white-tailed deer, Odocoileus virginianus (Zimmerman), at a coastal Massachusetts site. Deer abundance was reduced from an estimated 350 during 1985 to approximately 60 during 1991. Although annual fluctuations were large, mean larval I.

Perireceptor events in taste.

The microenvironment at chemical receptor sites is important for ligand-receptor interaction as it can influence the entry, residence time or exit of odorant and sapid molecules. The perireceptor milieu at apical taste cell microvilli consists of taste pore mucus and secretions from salivary glands. The majority of taste buds are sheltered in epithelial folds of the foliate and circumvallate papillae where saliva is provided predominantly by the lingual von Ebner's glands (VEGs).