A Tale of Two Valleys: Disparity in Sin Nombre Virus Antibody Reactivity Between Neighboring Mojave Desert Communities.

INTRODUCTION: Hantaviruses are a group of globally distributed rodent-associated viruses, some of which are responsible for human morbidity and mortality. Sin Nombre orthohantavirus, a particularly virulent species of hantavirus associated with Peromyscus spp. mice, is actively monitored by the Department of Public Health in California (CDPH). Recently, CDPH documented high (40%) seroprevalence in a potentially novel reservoir species, the cactus mouse (Peromyscus eremicus) in Death Valley National Park. METHODS: This study was performed in the extremely isolated Mojave Desert Amargosa River valley region of southeastern Inyo County, California, 105 km from Death Valley, approximately over the same time interval as the CDPH work in Death Valley (between 2011 and 2016). Similar rodent species were captured as in Death Valley and were tested for select hantaviruses using serology and RT-PCR to assess risk to human health and the conservation of the endemic endangered Amargosa vole. RESULTS: Among 192 rodents tested, including 56 Peromyscus spp., only one seropositive harvest mouse (Reithrodontomys megalotis) was detected. DISCUSSION: These data highlight the heterogeneity in the prevalence of hantavirus infection even among nearby desert communities and suggest that further studies of hantavirus persistence in desert environments are needed to more accurately inform the risks to public health and wildlife conservation.

Novel Focus of Sin Nombre Virus in Peromyscus eremicus Mice, Death Valley National Park, California, USA.

The deer mouse (Peromyscus maniculatus) is the primary reservoir for Sin Nombre virus (SNV) in the western United States. Rodent surveillance for hantavirus in Death Valley National Park, California, USA, revealed cactus mice (P. eremicus) as a possible focal reservoir for SNV in this location. We identified SNV antibodies in 40% of cactus mice sampled.

Assessing prevention measures and Sin Nombre hantavirus seroprevalence among workers at Yosemite National Park.

BACKGROUND: During 2012, a total of 10 overnight visitors to Yosemite National Park (Yosemite) became infected with a hantavirus (Sin Nombre virus [SNV]); three died. SNV infections have been identified among persons with occupational exposure to deer mice (Peromyscus maniculatus). METHODS: We assessed SNV infection prevalence, work and living environments, mice exposures, and SNV prevention training, knowledge, and practices among workers of two major employers at Yosemite during September-October, 2012 by voluntary blood testing and a questionnaire. RESULTS: One of 526 participants had evidence of previous SNV infection. Participants reported frequently observing rodent infestations at work and home and not always following prescribed safety practices for tasks, including infestation cleanup. CONCLUSION: Although participants had multiple exposures to deer mice, we did not find evidence of widespread SNV infections. Nevertheless, employees working around deer mice should receive appropriate training and consistently follow prevention policies for high-risk activities.

A cloud-compatible bioinformatics pipeline for ultrarapid pathogen identification from next-generation sequencing of clinical samples.

Unbiased next-generation sequencing (NGS) approaches enable comprehensive pathogen detection in the clinical microbiology laboratory and have numerous applications for public health surveillance, outbreak investigation, and the diagnosis of infectious diseases. However, practical deployment of the technology is hindered by the bioinformatics challenge of analyzing results accurately and in a clinically relevant timeframe. Here we describe SURPI ("sequence-based ultrarapid pathogen identification"), a computational pipeline for pathogen identification from complex metagenomic NGS data generated from clinical samples, and demonstrate use of the pipeline in the analysis of 237 clinical samples comprising more than 1.1 billion sequences. Deployable on both cloud-based and standalone servers, SURPI leverages two state-of-the-art aligners for accelerated analyses, SNAP and RAPSearch, which are as accurate as existing bioinformatics tools but orders of magnitude faster in performance. In fast mode, SURPI detects viruses and bacteria by scanning data sets of 7-500 million reads in 11 min to 5 h, while in comprehensive mode, all known microorganisms are identified, followed by de novo assembly and protein homology searches for divergent viruses in 50 min to 16 h. SURPI has also directly contributed to real-time microbial diagnosis in acutely ill patients, underscoring its potential key role in the development of unbiased NGS-based clinical assays in infectious diseases that demand rapid turnaround times.

Hantavirus infections among overnight visitors to Yosemite National Park, California, USA, 2012.

In summer 2012, an outbreak of hantavirus infections occurred among overnight visitors to Yosemite National Park in California, USA. An investigation encompassing clinical, epidemiologic, laboratory, and environmental factors identified 10 cases among residents of 3 states. Eight case-patients experienced hantavirus pulmonary syndrome, of whom 5 required intensive care with ventilatory support and 3 died. Staying overnight in a signature tent cabin (9 case-patients) was significantly associated with becoming infected with hantavirus (p<0.001). Rodent nests and tunnels were observed in the foam insulation of the cabin walls. Rodent trapping in the implicated area resulted in high trap success rate (51%), and antibodies reactive to Sin Nombre virus were detected in 10 (14%) of 73 captured deer mice. All signature tent cabins were closed and subsequently dismantled. Continuous public awareness and rodent control and exclusion are key measures in minimizing the risk for hantavirus infection in areas inhabited by deer mice.

Exposure to rodents and rodent-borne viruses among persons with elevated occupational risk.

Persons who have frequent contact with rodents as part of their occupation may be at increased risk of exposure to rodent-borne viruses such as Sin Nombre virus (SNV), the agent of hantavirus pulmonary syndrome, and Whitewater Arroyo virus (WWA), a New World arenavirus. Eighty-one persons with possible occupational exposure to rodents completed questionnaires and provided specimens for serologic testing. Seventy-two participants reported handling rodents as part of their job. The mean total number of rodents handled during participants' careers was approximately 2200. IgG antibody to lymphocytic choriomeningitis virus was detected in serum from one (1.2%) participant. IgG antibody to SNV, WWA, and Amapari viruses was not detected in any of the serum specimens. Despite considerable exposure to rodents, participants did not have significant serological evidence of exposure to rodent-borne viruses.

High incidence of HIV-1 in South Africa using a standardized algorithm for recent HIV seroconversion.

Southern Africa has among the highest rates of HIV-1 infection in the world as judged by cross-sectional HIV-1 prevalence surveys carried out among women attending antenatal clinics. Incidence rates, which provide information on the number of new cases of infection, are more informative of the current state of the epidemic than estimates of prevalence, which provide information on the rates averaged over some previous time. Cohort studies to measure incidence rates are expensive and difficult to carry out, however, and few have been done in Africa. A recently developed standardized algorithm for recent HIV-1 seroconversion (STARHS) based on a sensitive/less-sensitive enzyme-linked immunosorbent assay was used to determine the incidence of HIV-1 subtype C infection among women attending public sector antenatal clinics in Hlabisa, a rural district in KwaZulu-Natal, South Africa. The STAHRS results were confirmed by using a mathematic model to obtain an independent estimate of the age-specific incidence rates from the age-specific prevalence data. The data reveal extraordinarily high HIV-1 incidence rates in South Africa. In 1999, the annual incidence of HIV-1 among susceptible women aged 15 to 49 years standardized to the age distribution of adult women in Hlabisa was 17%. Incidence peaked among 22-year-old women at 24% per year. The HIV-1 incidence rates provide valuable additional information indicating that new infections are continuing unabated and that the HIV-1 epidemic is still growing in rural South Africa.