The per capita incidence of human Lyme disease in the northeastern United States is more than twice that in the Midwest. However, the prevalence of Borrelia burgdorferi, the bacterium that causes Lyme disease, in the tick vector is nearly identical in the 2 regions. The disparity in human Lyme disease incidence may result from a disparity in the human invasiveness of the bacteria in the Northeast and Midwest caused by fundamentally different evolutionary histories. B. burgdorferi populations in the Northeast and Midwest are geographically isolated, enabling evolutionary divergence in human invasiveness. However, we found that B. burgdorferi populations in the Northeast and Midwest shared a recent common ancestor, which suggests that substantial evolutionary divergence in human invasiveness has not occurred. We propose that differences in either animal ecology or human behavior are the root cause of the differences in human incidence between the 2 regions.

To monitor oseltamivir-resistant influenza viruses A (H1N1) (ORVs) with H275Y in neuraminidase (NA) in Japan during 2 influenza seasons, we analyzed 3,216 clinical samples by NA sequencing and/or NA inhibition assay. The total frequency of ORVs was 2.6% (45/1,734) during the 2007–08 season and 99.7% (1,477/1,482) during the 2008–09 season, indicating a marked increase in ORVs in Japan during 1 influenza season. The NA gene of ORVs in the 2007–08 season fell into 2 distinct lineages by D354G substitution, whereas that of ORVs in the 2008–09 season fell into 1 lineage. NA inhibition assay and M2 sequencing showed that almost all the ORVs were sensitive to zanamivir and amantadine. The hemagglutination inhibition test showed that ORVs were antigenetically similar to the 2008–09 vaccine strain A/Brisbane/59/2007. Our data indicate that the current vaccine or zanamivir and amantadine are effective against recent ORVs, but continuous surveillance remains necessary.

In 2008, a Trichinella spp. outbreak occurred on a small family-owned pig farm in Mecklenburg–Western Pomerania in northeastern Germany. To obtain epidemiologic information on this outbreak, we determined that after 2005 the prevalence of Trichinella spp. in wild boars has increased in this region of Germany. We discuss the potential role of the raccoon dog in the increase in Trichinella spp. prevalence in the sylvatic cycle in this region. We believe that this increase could pose a threat to pigs kept in back yard conditions, and we provide recommendations to ensure public health safety.

To determine the origin of the virus associated with a measles outbreak in Menglian County, Yunnan Province, People’s Republic of China, in 2009, we conducted genetic analyses. Phylogenetic analyses based on nucleoprotein (N) and hemagglutinin (H) gene sequences showed that these Menglian viruses were not closely related to sequences of any World Health Organization (WHO) reference strains representing the 23 currently recognized genotypes. The minimum nucleotide divergence between the Menglian viruses and the most closely related reference strain, genotype D7, was 3.3% for the N gene and 3.0% for the H gene. A search of the databases of GenBank, WHO, and the Health Protection Agency Measles Nucleotide Surveillance showed that the Menglian viruses, together with the 2 older non-Menglian viruses, could be members of a new proposed measles genotype, d11. The new genotype designation will allow for better description of measles transmission patterns, especially in the Southeast Asian and Western Pacific regions.

The emergence and spread of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) has raised public health concern about global control of TB. To estimate the transmission dynamics of MDR and XDR TB, we conducted a DNA fingerprinting analysis of 55 MDR/XDR Mycobacterium tuberculosis strains isolated from TB patients throughout Japan in 2002. Twenty-one (38%) of the strains were classified into 9 clusters with geographic links, which suggests that community transmission of MDR/XDR TB is ongoing. Furthermore, the XDR M. tuberculosis strains were more likely than the non–XDR MDR strains to be clustered (71% vs. 24%; p = 0.003), suggesting that transmission plays a critical role in the new incidence of XDR TB. These findings highlight the difficulty of preventing community transmission of XDR TB by conventional TB control programs and indicate an urgent need for a more appropriate strategy to contain highly developed drug-resistant TB.

To define the prevalence of pilus islet 2 (PI-2)–encoded pili in Streptococcus pneumoniae in a geographically defined area, we examined 590 S. pneumoniae isolates from population-based surveillance of invasive pneumococcal disease in Atlanta, Georgia, USA, 1994–2006. In 2006, PI-2 was present in 21% of all invasive isolates, including serotypes 1 (100%), 7F (89%), 11A (21%), 19A (40%), and 19F (75%). Only serotype 19F is included in the 7-valent pneumococcal conjugate vaccine that is in use worldwide. In 1999, PI-2-containing isolates were of the same serotypes but accounted for only 3.6% of all invasive isolates. The increase of PI-2 in 2006 resulted predominantly from the emergence of serotype 19A isolates of sequence type 320 and the expansion of serotype 7F isolates. The increase in PI-2-containing isolates and the finding that isolates of all identified serotypes expressed highly conserved PI-2 pili supports their potential as a vaccine candidate.

During 2 successive rainy seasons, January 2008 through May 2008 and November 2008 through March 2009, Rift Valley fever virus (RVFV) caused outbreaks in Madagascar. Human and animal infections were confirmed on the northern and southern coasts and in the central highlands. Analysis of partial sequences from RVFV strains showed that all were similar to the strains circulating in Kenya during 2006–2007. A national cross-sectional serologic survey among slaughterhouse workers at high risk showed that RVFV circulation during the 2008 outbreaks included all of the Malagasy regions and that the virus has circulated in at least 92 of Madagascar’s 111 districts. To better predict and respond to RVF outbreaks in Madagascar, further epidemiologic studies are needed, such as RVFV complete genome analysis, ruminant movement mapping, and surveillance implementation.

Encephalitis is a major cause of death worldwide. Although >100 pathogens have been identified as causative agents, the pathogen is not determined for up to 75% of cases. This diagnostic failure impedes effective treatment and underscores the need for better tools and new approaches for detecting novel pathogens or determining new manifestations of known pathogens. Although astroviruses are commonly associated with gastroenteritis, they have not been associated with central nervous system disease. Using unbiased pyrosequencing, we detected an astrovirus as the causative agent for encephalitis in a 15-year-old boy with agammaglobulinemia; several laboratories had failed to identify the agent. Our findings expand the spectrum of causative agents associated with encephalitis and highlight unbiased molecular technology as a valuable tool for differential diagnosis of unexplained disease.

We report 2 patients with invasive aspergillosis after infection with pandemic (H1N1) 2009. Influenza viruses are known to cause immunologic defects and impair ciliary clearance. These defects, combined with high-dose corticosteroids prescribed during influenza-associated adult respiratory distress syndrome, may be novel risk factors predisposing otherwise immunocompetent patients to invasive aspergillosis.

To determine which organisms most commonly cause infection after natural disasters, we cultured specimens from injured earthquake survivors in Wenchuan, China, 2008. Of 123 cultures, 46 (59%) grew only 1 type of pathogenic bacteria. Smear was more effective than culture for early diagnosis of gas gangrene. Early diagnosis and treatment of wounds are crucial.

To detect orthopoxvirus in the Brazilian Amazon, we conducted a serosurvey of 344 wild animals. Neutralizing antibodies against orthopoxvirus were detected by plaque-reduction neutralizing tests in 84 serum samples. Amplicons from 6 monkey samples were sequenced. These amplicons identified vaccinia virus genetically similar to strains from bovine vaccinia outbreaks in Brazil.

To identify the prevalence and genetic variability of noroviruses in dogs, we tested fecal samples by using reverse transcription–PCR. We found canine norovirus in 40% and 9% of dogs with and without diarrhea, respectively. The virus was genetically unrelated to other noroviruses and constitutes a tentative new genogroup.

To identify sources of transmission for area clusters, in 2007 the Houston Department of Health and Human Services conducted an 8-month study of enhanced surveillance of Salmonella infection. Protocol included patient interviews and linking the results of interviews to clusters of pulsed-field gel electrophoresis patterns detected by the local PulseNet laboratory.

Because bats are associated with emerging zoonoses, identification and characterization of novel viruses from bats is needed. Using a modified rapid determination system for viral RNA/DNA sequences, we identified a novel bat betaherpesvirus 2 not detected by herpesvirus consensus PCR. This modified system is useful for detecting unknown viruses.

Dengue virus type 3 genotype I was detected in Brazil during epidemics in 2002–2004. To confirm this finding, we identified this virus genotype in naturally infected field-caught Aedes aegypti mosquitoes and eggs. Results showed usefulness of virus investigations in vectors as a component of active epidemiologic surveillance.

To determine which respiratory viruses circulate among confined dogs, we analyzed nasal and pharyngeal swab specimens from shelter dogs with acute respiratory disease. An unknown virus was isolated. Monoclonal antibody testing indicated that it was probably a pneumovirus. PCR and sequence analysis indicated that it was closely related to murine pneumovirus.

To investigate a possible role for human rhinovirus C in respiratory exacerbations of children with cystic fibrosis, we conducted microbiologic testing on respiratory specimens from 103 such patients in São Paulo, Brazil, during 2006–2007. A significant association was found between the presence of human rhinovirus C and respiratory exacerbations.

Xenotropic murine leukemia virus–related gammaretrovirus (XMRV) has been recently associated with prostate cancer and chronic fatigue syndrome. To identify nucleic acid sequences, we examined respiratory secretions by using PCR. XMRV-specific sequences were detected in 2%–3% of samples from 168 immunocompetent carriers and ≈10% of samples from 161 immunocompromised patients.

To determine the epidemiology of human herpesvirus type 8 (HHV-8) among non-Amazonian native populations, we conducted a cross-sectional study in Brazil, Bolivia, and Paraquay. Our data show striking ethnic and geographic variations in the distribution of HHV-8 seroprevalences in Amazonian (77%) and non-Amazonian native populations (range 0%–83%).

We isolated arenavirus RNA from white-toothed woodrats (Neotoma leucodon) captured in a region of Mexico in which woodrats are food for humans. Analyses of nucleotide and amino acid sequence data indicated that the woodrats were infected with a novel Tacaribe serocomplex virus, proposed name Real de Catorce virus.

To understand the clinical and epidemiologic characteristics of pandemic (H1N1) 2009 virus infection, we retrospectively reviewed medical records of 237 patients with laboratory-confirmed cases reported in Shanghai, China, during May–July 2009. Surveillance activities effectively contained the outbreak and provided useful epidemiologic data for future strategies.

Klebsiella pneumoniae carbapenemase (KPC) 3–producing Escherichia coli was isolated from a carrier of KPC-3–producing K. pneumoniae. The KPC-3 plasmid was identical in isolates of both species. The patient's gut flora contained a carbapenem-susceptible E. coli strain isogenic with the KPC-3–producing isolate, which suggests horizontal interspecies plasmid transfer.

In an epidemiologic investigation of respiratory infections in Italy, October 2008–September 2009, we tested samples from patients for respiratory viruses. Human enterovirus genotype EV-104 (identified in Switzerland) was found in 3 immunocompromised and 2 immunocompetent patients. EV-104 is closely related to human rhinoviruses; thus, both types of viruses should be sought in respiratory syndromes.