Bites from the hard tick Amblyomma americanum are associated with a Lyme disease-like illness in the southern United States. To identify possible etiologic agents for this disorder, A. americanum ticks were collected in Missouri, Texas, New Jersey, and New York and examined microscopically. Uncultivable spirochetes were present in approximately 2% of the ticks. Borrelia genus-specific oligonucleotides for the flagellin and 16S rRNA genes were used for amplification of DNA. Products were obtained from ticks containing spirochetes by microscopy but not from spirochete-negative ticks. Sequences of partial genes from spirochetes in Texas and New Jersey ticks differed by only 2 of 641 nucleotides for flagellin and 2 of 1336 nucleotides for 16S rRNA. Phylogenetic analysis showed that the spirochete was a Borrelia species distinct from previously characterized members of this genus, including Borrelia burgdorferi. Gene amplification could be used to detect these spirochetes in ticks and possible mammalian hosts.

Some tick-borne agents may pose yet-unknown public health risks.

Summary From December 2005 through January 2006, the Minnesota Department of Health (MDH) identified four human clinical isolates of Salmonella Typhimurium that were indistinguishable by pulsed‐field gel electrophoresis (PFGE). During routine interviews, three of the cases reported attending the same junior high school and two handled snakes in the science classroom. MDH collected environmental samples from the school’s science classroom for Salmonella culturing; these included environmental samples and frozen vacuum‐packed mice purchased over the internet to feed the classroom snakes. Through PulseNet, a national molecular subtyping surveillance network for enteric bacteria, 21 human S. Typhimurium isolates with indistinguishable PFGE patterns were identified in the United States since December 2005. Each state determined whether these human cases had recent exposure to snakes fed vacuum‐packed rodents. Texas state officials conducted tracebacks of the vacuum‐packed mice and collected samples at the breeding facility. Nineteen of 21 cases were interviewed, and seven reported contact with frozen vacuum‐packed rodents from the same internet‐based supplier in Texas. In Minnesota, the outbreak PFGE subtype of S. Typhimurium was isolated from the snakes, frozen feed rodents, and the classroom environment. Three human cases were identified in Michigan, Pennsylvania, and Wyoming. The outbreak PFGE subtype of S. Typhimurium was isolated from the Pennsylvania case’s frozen rodents and the Michigan case’s pet snake. The outbreak PFGE subtype of S. Typhimurium was also isolated from the supplier’s rodent facility. This was a S. Typhimurium outbreak associated with frozen rodents. Human transmission likely occurred through direct contact with snakes and contaminated environmental surfaces. This report represents the second recent multi‐state salmonellosis outbreak associated with commercially distributed rodents. Stronger oversight of the commercial rodent industry is warranted.

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Pokeweed antiviral protein at a concentration of 3 FM inhibited both the synthesis and release of infectious herpes simplex virus type 1 in cell culture by 90 and 99%, respectively. Addition of pokeweed antiviral protein to Vero cell monolayers before virus infection was 10 to 15% more effective in reducing virus yields than was the simultaneous addition of the antiviral protein with virus inoculum. Viral DNA synthesis was inhibited by 90% in cells which had been exposed to the antiviral protein, whereas cellular DNA synthesis was unaffected. No significant inhibition in the synthesis of the majority of viral infected-cell polypeptides was observed early postinfection (7 h), with the exception of infected cell polypeptides 4 and 41, whose syntheses were reduced by 38 and 25%, respectively. At 9 to 21 h postinfection, however, the synthesis of individual infected cell polypeptides was reduced by 48 to >99%.Pokeweed (Phytolacca americana) antiviral protein (PAP) is a basic protein with a molecular weight of 29,000 (29K) (9). PAP has been shown to inhibit the transmission of several plant viruses (20,22) as well as the multiplication of poliovirus (21), influenza virus (20) and herpes simplex virus (HSV) (1) in cell culture. PAP has also been reported to inhibit eucaryotic protein synthesis in cell-free systems derived from rabbit reticulocytes (13) and in poliovirus-infected HeLa cells (21). This inhibition is due to the enzymatic inactivation of ribosomes, which in turn primarily inhibits the action of elongation factor EF-2 (6, 13). In contrast, PAP causes little cytotoxicity to uninfected cells (11, 21), suggesting that PAP is unable to enter intact, uninfected cells. It has been postulated, therefore, that the antiviral activity of PAP is dependent upon. a virus-cell interaction which facilitates the entry of PAP into the host cell, followed by the inactivation of the ribosomes of the host cell by PAP (21).The results presented in this paper demonstrate that the antiviral activity of PAP against herpes simplex virus is due to a selective inhibition of viral DNA synthesis rather than an enzymatic inactivation of the ribosomes of the host cell. We also present evidence which indicates that (i) PAP inhibits not only the synthesis of infectious virus but also release from the infected cell and (ii) a PAP-cell interaction is an initial step in the antiviral mechanism of PAP, followed by a virus-cell interaction.

culturing the Lyme disease spirochete Borrelia burgdorferi in 1985. This organism was subsequently isolated from blood, cerebrospinal fluid, joint fluid, skin, bone, and autopsy tissues from humans. Fluorescent-antibody tests with murine monoclonal antibodies confirmed that seven of these isolates were B. burgdorferi and that two others belonged to the genus Borrelia. Lyme disease, first recognized in 1975, is a tick-borne infection that can result in long-term rheumatologic or neurologic disorders. A spirochete isolated from Ixodes dammini in 1982 was later found to be the etiologic agent of the illness (6, 16). Since then, this bacterium, called Borrelia burgdorferi, has been detected in tissue specimens from patients who were diagnosed clinically as having Lyme disease (4, 5, 8, 9, 16). These specimens include blood, cerebrospinal fluid (CSF), joint fluids, and skin tissues. At the Texas Department of Health, we began culturing for B. burgdorferi during the spring of 1985. Blood, CSF, joint fluids, bone scrapings, autopsy tissues, and skin tissues from patients whose physicians suspected Lyme disease were submitted to our laboratory. These specimens were placed in modified BSK II medium in an attempt to isolate B. burgdorferi (1). Our findings are reported here. MATERIALS AND METHODS Specimens were collected by physicians and shipped overnight to the Texas Department of Health Laboratory in Austin. Blood, CSF, and joint fluids were sent either on wet or dry ice; skin and autopsy tissues were shipped in approximately 1 ml of either brain heart infusion or thioglycolate medium; and bone scrapings (from the right wrist of the patient) were placed directly into BSK II medium by the physician.

Between 1990 and 1992, ticks from eight Texas parks were collected and analyzed to determine the prevalence of spirochete-infected ticks. Borrelia spirochetes were detected in 1.03% of 5,141 Amblyomma americanum (L.) adults examined, a species Texas residents often encounter. No spirochetes were observed in the other tick species tested.

Since the first reported case in 1941, Rocky Mountain spotted fever in humans has been reported from many areas of Texas, with two major foci, one located in the north-central region and the other in the eastern region of the state. During the period 1979-1988, 421 cases of RMSF were reported, reaching 108 cases in 1983 and declining in subsequent years. Statewide surveillance programs to detect spotted fever group rickettsiae in tick populations were initiated in 1976. In recent years, the SFG infectivity rates in these tick species have included Dermacentor variabilis, 5.2%; Amblyomma americanum, 7.1%; Rhipicephalus sanguineus, 2.9%; and Ixodes scapularis, 10.2%. Further determination of involved rickettsial species and pathogenicity is needed, as many of these specimens are collected from humans and during epidemiological investigations. Various foci of murine typhus occur in Texas. During 1979-1988, 400 human cases were reported. The majority of cases occurred in people who resided in south Texas. Several investigations have shown a possible link between typhus infections and exposure to Ctenocephalides felis. Other rickettsial infections currently reported in Texas include Q fever and ehrlichiosis.