Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) outbreaks in nursing homes involving residents who had completed a primary coronavirus disease 2019 (COVID-19) vaccine series-13 US jurisdictions, July-November 2021

Among nursing home outbreaks of coronavirus disease 2019 (COVID-19) with ≥3 breakthrough infections when the predominant severe acute respiratory coronavirus virus 2 (SARS-CoV-2) variant circulating was the SARS-CoV-2 δ (delta) variant, fully vaccinated residents were 28% less likely to be infected than were unvaccinated residents. Once infected, they had approximately half the risk for all-cause hospitalization and all-cause death compared with unvaccinated infected residents.

Outbreaks of SARS-CoV-2 Infections in Nursing Homes during Periods of Delta and Omicron Predominance, United States, July 2021-March 2022

SARS-CoV-2 infections among vaccinated nursing home residents increased after the Omicron variant emerged. Data on booster dose effectiveness in this population are limited. During July 2021-March 2022, nursing home outbreaks in 11 US jurisdictions involving >3 infections within 14 days among residents who had received at least the primary COVID-19 vaccine(s) were monitored. Among 2,188 nursing homes, 1,247 outbreaks were reported in the periods of Delta (n = 356, 29%), mixed Delta/Omicron (n = 354, 28%), and Omicron (n = 536, 43%) predominance. During the Omicron-predominant period, the risk for infection within 14 days of an outbreak start was lower among boosted residents than among residents who had received the primary vaccine series alone (risk ratio [RR] 0.25, 95% CI 0.19-0.33). Once infected, boosted residents were at lower risk for all-cause hospitalization (RR 0.48, 95% CI 0.40-0.49) and death (RR 0.45, 95% CI 0.34-0.59) than primary vaccine-only residents.

Evaluation of a Virtual Training to Enhance Public Health Capacity for COVID-19 Infection Prevention and Control in Nursing Homes

CONTEXT

Between April 2020 and May 2021, the Centers for Disease Control and Prevention (CDC) awarded more than $40 billion to health departments nationwide for COVID-19 prevention and response activities. One of the identified priorities for this investment was improving infection prevention and control (IPC) in nursing homes.

PROGRAM

CDC developed a virtual course to train new and less experienced public health staff in core healthcare IPC principles and in the application of CDC COVID-19 healthcare IPC guidance for nursing homes.

IMPLEMENTATION

From October 2020 to August 2021, the CDC led training sessions for 12 cohorts of public health staff using pretraining reading materials, case-based scenarios, didactic presentations, peer-learning opportunities, and subject matter expert-led discussions. Multiple electronic assessments were distributed to learners over time to measure changes in self-reported knowledge and confidence and to collect feedback on the course. Participating public health programs were also assessed to measure overall course impact.

EVALUATION

Among 182 enrolled learners, 94% completed the training. Most learners were infection preventionists (42%) or epidemiologists (38%), had less than 1 year of experience in their health department role (75%), and had less than 1 year of subject matter experience (54%). After training, learners reported increased knowledge and confidence in applying the CDC COVID-19 healthcare IPC guidance for nursing homes (≥81%) with the greatest increase in performing COVID-19 IPC consultations and assessments (87%). The majority of participating programs agreed that the course provided an overall benefit (88%) and reduced training burden (72%).

DISCUSSION

The CDC's virtual course was effective in increasing public health capacity for COVID-19 healthcare IPC in nursing homes and provides a possible model to increase IPC capacity for other infectious diseases and other healthcare settings. Future virtual healthcare IPC courses could be enhanced by tailoring materials to health department needs, reinforcing training through applied learning experiences, and supporting mechanisms to retain trained staff.

Investigation of a Suspect Severe Acute Respiratory Syndrome Coronavirus-2 and Influenza A Mixed Outbreak: Lessons Learned for Long-Term Care Facilities Nationwide

A suspected outbreak of influenza A and SARS-CoV-2 at a long-term care facility in Los Angeles County was months later, determined to not involve influenza. To prevent inadvertent transmission of infections, facilities should use highly specific influenza diagnostics and follow CDC guidelines that specifically address infection control challenges.

Lack of Serologic Evidence of Infection Among Health Care Personnel and Other Contacts of First 2 Confirmed Patients With COVID-19 in Illinois, 2020

OBJECTIVES

Widespread global transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19), continues. Many questions remain about asymptomatic or atypical infections and transmission dynamics. We used comprehensive contact tracing of the first 2 confirmed patients in Illinois with COVID-19 and serologic SARS-CoV-2 antibody testing to determine whether contacts had evidence of undetected COVID-19.

METHODS

Contacts were eligible for serologic follow-up if previously tested for COVID-19 during an initial investigation or had greater-risk exposures. Contacts completed a standardized questionnaire during the initial investigation. We classified exposure risk as high, medium, or low based on interactions with 2 index patients and use of personal protective equipment (PPE). Serologic testing used a SARS-CoV-2 spike enzyme-linked immunosorbent assay on serum specimens collected from participants approximately 6 weeks after initial exposure to either index patient. The 2 index patients provided serum specimens throughout their illness. We collected data on demographic, exposure, and epidemiologic characteristics.

RESULTS

Of 347 contacts, 110 were eligible for serologic follow-up; 59 (17% of all contacts) enrolled. Of these, 53 (90%) were health care personnel and 6 (10%) were community contacts. Seventeen (29%) reported high-risk exposures, 15 (25%) medium-risk, and 27 (46%) low-risk. No participant had evidence of SARS-CoV-2 antibodies. The 2 index patients had antibodies detected at dilutions >1:6400 within 4 weeks after symptom onset.

CONCLUSIONS

In serologic follow-up of the first 2 known patients in Illinois with COVID-19, we found no secondary transmission among tested contacts. Lack of seroconversion among these contacts adds to our understanding of conditions (ie, use of PPE) under which SARS-CoV-2 infections might not result in transmission and demonstrates that SARS-CoV-2 antibody testing is a useful tool to verify epidemiologic findings.

Clinical and virologic characteristics of the first 12 patients with coronavirus disease 2019 (COVID-19) in the United States

Data on the detailed clinical progression of COVID-19 in conjunction with epidemiological and virological characteristics are limited. In this case series, we describe the first 12 US patients confirmed to have COVID-19 from 20 January to 5 February 2020, including 4 patients described previously^1-3. Respiratory, stool, serum and urine specimens were submitted for SARS-CoV-2 real-time reverse-transcription polymerase chain reaction (rRT-PCR) testing, viral culture and whole genome sequencing. Median age was 53 years (range: 21-68); 8 patients were male. Common symptoms at illness onset were cough (n = 8) and fever (n = 7). Patients had mild to moderately severe illness; seven were hospitalized and demonstrated clinical or laboratory signs of worsening during the second week of illness. No patients required mechanical ventilation and all recovered. All had SARS-CoV-2 RNA detected in respiratory specimens, typically for 2-3 weeks after illness onset. Lowest real-time PCR with reverse transcription cycle threshold values in the upper respiratory tract were often detected in the first week and SARS-CoV-2 was cultured from early respiratory specimens. These data provide insight into the natural history of SARS-CoV-2. Although infectiousness is unclear, highest viral RNA levels were identified in the first week of illness. Clinicians should anticipate that some patients may worsen in the second week of illness.

First known person-to-person transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the USA

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first detected in China in December, 2019. In January, 2020, state, local, and federal public health agencies investigated the first case of COVID-19 in Illinois, USA.

METHODS

Patients with confirmed COVID-19 were defined as those with a positive SARS-CoV-2 test. Contacts were people with exposure to a patient with COVID-19 on or after the patient's symptom onset date. Contacts underwent active symptom monitoring for 14 days following their last exposure. Contacts who developed fever, cough, or shortness of breath became persons under investigation and were tested for SARS-CoV-2. A convenience sample of 32 asymptomatic health-care personnel contacts were also tested.

FINDINGS

Patient 1-a woman in her 60s-returned from China in mid-January, 2020. One week later, she was hospitalised with pneumonia and tested positive for SARS-CoV-2. Her husband (Patient 2) did not travel but had frequent close contact with his wife. He was admitted 8 days later and tested positive for SARS-CoV-2. Overall, 372 contacts of both cases were identified; 347 underwent active symptom monitoring, including 152 community contacts and 195 health-care personnel. Of monitored contacts, 43 became persons under investigation, in addition to Patient 2. These 43 persons under investigation and all 32 asymptomatic health-care personnel tested negative for SARS-CoV-2.

INTERPRETATION

Person-to-person transmission of SARS-CoV-2 occurred between two people with prolonged, unprotected exposure while Patient 1 was symptomatic. Despite active symptom monitoring and testing of symptomatic and some asymptomatic contacts, no further transmission was detected.

FUNDING

None.

Differences Among Incidence Rates of Invasive Listeriosis in the U.S. FoodNet Population by Age, Sex, Race/Ethnicity, and Pregnancy Status, 2008-2016

Listeria monocytogenes is a foodborne pathogen that disproportionally affects pregnant females, older adults, and immunocompromised individuals. Using U.S. Foodborne Diseases Active Surveillance Network (FoodNet) surveillance data, we examined listeriosis incidence rates and rate ratios (RRs) by age, sex, race/ethnicity, and pregnancy status across three periods from 2008 to 2016, as recent incidence trends in U.S. subgroups had not been evaluated. The invasive listeriosis annual incidence rate per 100,000 for 2008-2016 was 0.28 cases among the general population (excluding pregnant females), and 3.73 cases among pregnant females. For adults ≥70 years, the annual incidence rate per 100,000 was 1.33 cases. No significant change in estimated listeriosis incidence was found over the 2008-2016 period, except for a small, but significantly lower pregnancy-associated rate in 2011-2013 when compared with 2008-2010. Among the nonpregnancy-associated cases, RRs increased with age from 0.43 (95% confidence interval: 0.25-0.73) for 0- to 14-year olds to 44.9 (33.5-60.0) for ≥85-year olds, compared with 15- to 44-year olds. Males had an incidence of 1.28 (1.12-1.45) times that of females. Compared with non-Hispanic whites, the incidence was 1.57 (1.18-1.20) times higher among non-Hispanic Asians, 1.49 (1.22-1.83) among non-Hispanic blacks, and 1.73 (1.15-2.62) among Hispanics. Among females of childbearing age, non-Hispanic Asian females had 2.72 (1.51-4.89) and Hispanic females 3.13 (2.12-4.89) times higher incidence than non-Hispanic whites. We observed a higher percentage of deaths among older patient groups compared with 15- to 44-year olds. This study is the first characterizing higher RRs for listeriosis in the United States among non-Hispanic blacks and Asians compared with non-Hispanic whites. This information for public health risk managers may spur further research to understand if differences in listeriosis rates relate to differences in consumption patterns of foods with higher contamination levels, food handling practices, comorbidities, immunodeficiencies, health care access, or other factors.

449. Post-Hurricane Maria Surveillance for Infectious Diseases in the Veterans Affairs San Juan Medical Center, Puerto Rico

Background

On September 20, 2017 Category 4 Hurricane Maria made landfall in Puerto Rico (PR), causing widespread flooding, power outages, and lack of water service. Given the potential for infectious disease outbreaks, the Department of Veterans Affairs (VA) and Centers for Disease Control and Prevention established enhanced surveillance to actively monitor priority infections at VA facilities.

Methods

We queried VA data sources from August 27, 2017 to February 3, 2018 (pre-storm dates included to establish baselines). Trends in infectious disease ICD-10 syndrome groupings (respiratory illness/pneumonia, Influenza-like illness (ILI), gastrointestinal illness, conjunctivitis, rash-like Illness, jaundice) as a percent of total emergency department (ED) visits were tracked. The total number of laboratory tests performed, and percent positive per week, for influenza, hepatitis A, dengue (DENV), zika (ZIKV), leptospirosis, and chikungunya (CHIKV) were calculated.

Results

ILI increased from 9.3% to 12.6% during the surveillance period (peak epi week 52: 15.7%) (Figure 1), while other ICD-10–based syndromes remained relatively stable. Weekly influenza testing increased shortly after landfall averaging 105 rapid influenza tests per week (epi weeks 41–4) (Figure 2). Influenza positivity increased in epi weeks 41 and 42 (7%), dropping the following weeks, and peaked at 15% in epi week 2 (Figure 3). Four acute infections were detected: 2 + leptospirosis DNA, 1 + CHIKV RNA, and 1 + Hepatitis A IgM. The remaining 34 positive tests were ZIKV, CHIKV, or DENV IgM positive or equivocal, awaiting confirmation (Figure 3).

Conclusion

We quickly established a simple surveillance system to monitor trends in priority infectious diseases. Increases in ILI, weekly influenza testing volume, and percent positive of influenza tests coincided with onset of influenza season. Diseases of public health importance were identified through laboratory-based surveillance. The impact of Maria on VA healthcare operations, including clinic closures, power outages, and disrupted care seeking patterns limited this system. However, the timeliness and flexibility of this surveillance system provides a model for disease monitoring following future natural disasters.

Disclosures

All authors: No reported disclosures.

Listeriosis Outbreaks Associated with Soft Cheeses, United States, 1998-20141

Since 2006, the number of reported US listeriosis outbreaks associated with cheese made under unsanitary conditions has increased. Two-thirds were linked to Latin-style soft cheese, often affecting pregnant Hispanic women and their newborns. Adherence to pasteurization protocols and sanitation measures to avoid contamination after pasteurization can reduce future outbreaks.

Response to Emergence of Middle East Respiratory Syndrome Coronavirus, Abu Dhabi, United Arab Emirates, 2013-2014

We found that this virus may be detected in mildly ill and asymptomatic case-patients.

In January 2013, several months after Middle East respiratory syndrome coronavirus (MERS-CoV) was first identified in Saudi Arabia, Abu Dhabi, United Arab Emirates, began surveillance for MERS-CoV. We analyzed medical chart and laboratory data collected by the Health Authority–Abu Dhabi during January 2013–May 2014. Using real-time reverse transcription PCR, we tested respiratory tract samples for MERS-CoV and identified 65 case-patients. Of these patients, 23 (35%) were asymptomatic at the time of testing, and 4 (6%) showed positive test results for >3 weeks (1 had severe symptoms and 3 had mild symptoms). We also identified 6 clusters of MERS-CoV cases. This report highlights the potential for virus shedding by mildly ill and asymptomatic case-patients. These findings will be useful for MERS-CoV management and infection prevention strategies.

Transmission of Middle East Respiratory Syndrome Coronavirus Infections in Healthcare Settings, Abu Dhabi

Early detection and adherence to infection prevention recommendations are necessary to avoid transmission.

Middle East respiratory syndrome coronavirus (MERS-CoV) infections sharply increased in the Arabian Peninsula during spring 2014. In Abu Dhabi, United Arab Emirates, these infections occurred primarily among healthcare workers and patients. To identify and describe epidemiologic and clinical characteristics of persons with healthcare-associated infection, we reviewed laboratory-confirmed MERS-CoV cases reported to the Health Authority of Abu Dhabi during January 1, 2013–May 9, 2014. Of 65 case-patients identified with MERS-CoV infection, 27 (42%) had healthcare-associated cases. Epidemiologic and genetic sequencing findings suggest that 3 healthcare clusters of MERS-CoV infection occurred, including 1 that resulted in 20 infected persons in 1 hospital. MERS-CoV in healthcare settings spread predominantly before MERS-CoV infection was diagnosed, underscoring the importance of increasing awareness and infection control measures at first points of entry to healthcare facilities.

Burden of Nursing Home-Onset Clostridium difficile Infection in the United States: Estimates of Incidence and Patient Outcomes

Background.  Approximately 4 million Americans receive nursing home (NH) care annually. Nursing home residents commonly have risk factors for Clostridium difficile infection (CDI), including advanced age and antibiotic exposures. We estimated national incidence of NH-onset (NHO) CDI and patient outcomes. Methods.  We identified NHO-CDI cases from population-based surveillance of 10 geographic areas in the United States. Cases were defined by C difficile-positive stool collected in an NH (or from NH residents in outpatient settings or ≤3 days after hospital admission) without a positive stool in the prior 8 weeks. Medical records were reviewed on a sample of cases. Incidence was estimated using regression models accounting for age and laboratory testing method; sampling weights were applied to estimate hospitalizations, recurrences, and deaths. Results.  A total of 3503 NHO-CDI cases were identified. Among 262 sampled cases, median age was 82 years, 76% received antibiotics in the 12 weeks prior to the C difficile-positive specimen, and 57% were discharged from a hospital in the month before specimen collection. After adjusting for age and testing method, the 2012 national estimate for NHO-CDI incidence was 112 800 cases (95% confidence interval [CI], 93 400-131 800); 31 400 (28%) were hospitalized within 7 days after a positive specimen (95% CI, 25 500-37 300), 20 900 (19%) recurred within 14-60 days (95% CI, 14 600-27 100), and 8700 (8%) died within 30 days (95% CI, 6600-10 700). Conclusions.  Nursing home onset CDI is associated with substantial morbidity and mortality. Strategies focused on infection prevention in NHs and appropriate antibiotic use in both NHs and acute care settings may decrease the burden of NHO CDI.

Evolution of ebola virus disease from exotic infection to global health priority, Liberia, mid-2014

As the disease spread, the scale of the epidemic required a multi-faceted public health response.

Over the span of a few weeks during July and August 2014, events in West Africa changed perceptions of Ebola virus disease (EVD) from an exotic tropical disease to a priority for global health security. We describe observations during that time of a field team from the Centers for Disease Control and Prevention and personnel of the Liberian Ministry of Health and Social Welfare. We outline the early epidemiology of EVD within Liberia, including the practical limitations on surveillance and the effect on the country’s health care system, such as infections among health care workers. During this time, priorities included strengthening EVD surveillance; establishing safe settings for EVD patient care (and considering alternative isolation and care models when Ebola Treatment Units were overwhelmed); improving infection control practices; establishing an incident management system; and working with Liberian airport authorities to implement EVD screening of departing passengers.

Active Tracing and Monitoring of Contacts Associated With the First Cluster of Ebola in the United States

BACKGROUND

Following hospitalization of the first patient with Ebola virus disease diagnosed in the United States on 28 September 2014, contact tracing methods for Ebola were implemented.

OBJECTIVE

To identify, risk-stratify, and monitor contacts of patients with Ebola.

DESIGN

Descriptive investigation.

SETTING

Dallas County, Texas, September to November 2014.

PARTICIPANTS

Contacts of symptomatic patients with Ebola.

MEASUREMENTS

Contact identification, exposure risk classification, symptom development, and Ebola.

RESULTS

The investigation identified 179 contacts, 139 of whom were contacts of the index patient. Of 112 health care personnel (HCP) contacts of the index case, 22 (20%) had known unprotected exposures and 37 (30%) did not have known unprotected exposures but interacted with a patient or contaminated environment on multiple days. Transmission was confirmed in 2 HCP who had substantial interaction with the patient while wearing personal protective equipment. These HCP had 40 additional contacts. Of 20 community contacts of the index patient or the 2 HCP, 4 had high-risk exposures. Movement restrictions were extended to all 179 contacts; 7 contacts were quarantined. Seven percent (14 of 179) of contacts (1 community contact and 13 health care contacts) were evaluated for Ebola during the monitoring period.

LIMITATION

Data cannot be used to infer whether in-person direct active monitoring is superior to active monitoring alone for early detection of symptomatic contacts.

CONCLUSION

Contact tracing and monitoring approaches for Ebola were adapted to account for the evolving understanding of risks for unrecognized HCP transmission. HCP contacts in the United States without known unprotected exposures should be considered as having a low (but not zero) risk for Ebola and should be actively monitored for symptoms. Core challenges of contact tracing for high-consequence communicable diseases included rapid comprehensive contact identification, large-scale direct active monitoring of contacts, large-scale application of movement restrictions, and necessity of humanitarian support services to meet nonclinical needs of contacts.

PRIMARY FUNDING SOURCE

None.

Notes from the field: Adverse events associated with administration of simulation intravenous fluids to patients--United States, 2014

On December 23, 2014, the New York State Department of Health (NYSDOH) was notified of adverse health events in two patients who had been inadvertently administered nonsterile, simulation 0.9% sodium chloride intravenous (IV) fluids at an urgent care facility. Simulation saline is a nonsterile product not meant for human or animal use; it is intended for use by medical trainees practicing IV administration of saline on mannequins or other training devices. Both patients experienced a febrile illness during product administration and were hospitalized; one patient developed sepsis and disseminated intravascular coagulation. Neither patient died. Staff members at the clinic reported having ordered the product through their normal medical supply distributor and not recognizing during administration that it was not intended for human use.

The epidemiology and surveillance workforce among local health departments in California: mutual aid and surge capacity for routine and emergency infectious disease situations

OBJECTIVE

Public health surveillance and epidemiologic investigations are critical public health functions for identifying threats to the health of a community. We conducted a survey of local health departments (LHDs) in California to describe the workforce that supports public health surveillance and epidemiologic functions during routine and emergency infectious disease situations.

METHODS

The target population consisted of the 61 LHDs in California. The online survey instrument was designed to collect information about the workforce involved in key epidemiologic functions. We also examined how the public health workforce increases its epidemiologic capacity during infectious disease emergencies.

RESULTS

Of 61 LHDs in California, 31 (51%) completed the survey. A wide range of job classifications contribute to epidemiologic functions routinely, and LHDs rely on both internal and external sources of epidemiologic surge capacity during infectious disease emergencies. This study found that while 17 (55%) LHDs reported having a mutual aid agreement with at least one other organization for emergency response, only nine (29%) LHDs have a mutual aid agreement specifically for epidemiology and surveillance functions.

CONCLUSIONS

LHDs rely on a diverse workforce to conduct epidemiology and public health surveillance functions, emphasizing the need to identify and describe the types of staff positions that could benefit from public health surveillance and epidemiology training. While some organizations collaborate with external partners to support these functions during an emergency, many LHDs do not rely on mutual aid agreements for epidemiology and surveillance activities.

Ebola virus disease cases among health care workers not working in Ebola treatment units--Liberia, June-August, 2014

West Africa is experiencing the largest Ebola virus disease (Ebola) epidemic in recorded history. Health care workers (HCWs) are at increased risk for Ebola. In Liberia, as of August 14, 2014, a total of 810 cases of Ebola had been reported, including 10 clusters of Ebola cases among HCWs working in facilities that were not Ebola treatment units (non-ETUs). The Liberian Ministry of Health and Social Welfare and CDC investigated these clusters by reviewing surveillance data, interviewing county health officials, HCWs, and contact tracers, and visiting health care facilities. Ninety-seven cases of Ebola (12% of the estimated total) were identified among HCWs; 62 HCW cases (64%) were part of 10 distinct clusters in non-ETU health care facilities, primarily hospitals. Early recognition and diagnosis of Ebola in patients who were the likely source of introduction to the HCWs (i.e., source patients) was missed in four clusters. Inconsistent recognition and triage of cases of Ebola, overcrowding, limitations in layout of physical spaces, lack of training in the use of and adequate supply of personal protective equipment (PPE), and limited supervision to ensure consistent adherence to infection control practices all were observed. Improving infection control infrastructure in non-ETUs is essential for protecting HCWs. Since August, the Liberian Ministry of Health and Social Welfare with a consortium of partners have undertaken collaborative efforts to strengthen infection control infrastructure in non-ETU health facilities.

Developing an incident management system to support Ebola response -- Liberia, July-August 2014

The ongoing Ebola virus disease (Ebola) outbreak in West Africa is the largest and most sustained Ebola epidemic recorded, with 6,574 cases. Among the five affected countries of West Africa (Liberia, Sierra Leone, Guinea, Nigeria, and Senegal), Liberia has had the highest number cases (3,458). This epidemic has severely strained the public health and health care infrastructure of Liberia, has resulted in restrictions in civil liberties, and has disrupted international travel. As part of the initial response, the Liberian Ministry of Health and Social Welfare (MOHSW) developed a national task force and technical expert committee to oversee the management of the Ebola-related activities. During the third week of July 2014, CDC deployed a team of epidemiologists, data management specialists, emergency management specialists, and health communicators to assist MOHSW in its response to the growing Ebola epidemic. One aspect of CDC's response was to work with MOHSW in instituting incident management system (IMS) principles to enhance the organization of the response. This report describes MOHSW's Ebola response structure as of mid-July, the plans made during the initial assessment of the response structure, the implementation of interventions aimed at improving the system, and plans for further development of the response structure for the Ebola epidemic in Liberia.

Cluster of Ebola cases among Liberian and U.S. health care workers in an Ebola treatment unit and adjacent hospital -- Liberia, 2014

The ongoing Ebola virus disease (Ebola) epidemic in West Africa, like previous Ebola outbreaks, has been characterized by amplification in health care settings and increased risk for health care workers (HCWs), who often do not have access to appropriate personal protective equipment. In many locations, Ebola treatment units (ETUs) have been established to optimize care of patients with Ebola while maintaining infection control procedures to prevent transmission of Ebola virus. These ETUs are considered essential to containment of the epidemic. In July 2014, CDC assisted the Ministry of Health and Social Welfare of Liberia in investigating a cluster of five Ebola cases among HCWs who became ill while working in an ETU, an adjacent general hospital, or both. No common source of exposure or chain of transmission was identified. However, multiple opportunities existed for transmission of Ebola virus to HCWs, including exposure to patients with undetected Ebola in the hospital, inadequate use of personal protective equipment during cleaning and disinfection of environmental surfaces in the hospital, and potential transmission from an ill HCW to another HCW. No evidence was found of a previously unrecognized mode of transmission. Prevention recommendations included reinforcement of existing infection control guidance for both ETUs and general medical care settings, including measures to prevent cross-transmission in co-located facilities.

New Delhi metallo-β-lactamase-producing carbapenem-resistant Escherichia coli associated with exposure to duodenoscopes

IMPORTANCE

Carbapenem-resistant Enterobacteriaceae (CRE) producing the New Delhi metallo-β-lactamase (NDM) are rare in the United States, but have the potential to add to the increasing CRE burden. Previous NDM-producing CRE clusters have been attributed to person-to-person transmission in health care facilities.

OBJECTIVE

To identify a source for, and interrupt transmission of, NDM-producing CRE in a northeastern Illinois hospital.

DESIGN, SETTING, AND PARTICIPANTS

Outbreak investigation among 39 case patients at a tertiary care hospital in northeastern Illinois, including a case-control study, infection control assessment, and collection of environmental and device cultures; patient and environmental isolate relatedness was evaluated with pulsed-field gel electrophoresis (PFGE). Following identification of a likely source, targeted patient notification and CRE screening cultures were performed.

MAIN OUTCOMES AND MEASURES

Association between exposure and acquisition of NDM-producing CRE; results of environmental cultures and organism typing.

RESULTS

In total, 39 case patients were identified from January 2013 through December 2013, 35 with duodenoscope exposure in 1 hospital. No lapses in duodenoscope reprocessing were identified; however, NDM-producing Escherichia coli was recovered from a reprocessed duodenoscope and shared more than 92% similarity to all case patient isolates by PFGE. Based on the case-control study, case patients had significantly higher odds of being exposed to a duodenoscope (odds ratio [OR], 78 [95% CI, 6.0-1008], P < .001). After the hospital changed its reprocessing procedure from automated high-level disinfection with ortho-phthalaldehyde to gas sterilization with ethylene oxide, no additional case patients were identified.

CONCLUSIONS AND RELEVANCE

In this investigation, exposure to duodenoscopes with bacterial contamination was associated with apparent transmission of NDM-producing E coli among patients at 1 hospital. Bacterial contamination of duodenoscopes appeared to persist despite the absence of recognized reprocessing lapses. Facilities should be aware of the potential for transmission of bacteria including antimicrobial-resistant organisms via this route and should conduct regular reviews of their duodenoscope reprocessing procedures to ensure optimal manual cleaning and disinfection.

Public health response systems in-action: learning from local health departments' experiences with acute and emergency incidents

As part of their core mission, public health agencies attend to a wide range of disease and health threats, including those that require routine, acute, and emergency responses. While each incident is unique, the number and type of response activities are finite; therefore, through comparative analysis, we can learn about commonalities in the response patterns that could improve predictions and expectations regarding the resources and capabilities required to respond to future acute events. In this study, we interviewed representatives from more than 120 local health departments regarding their recent experiences with real-world acute public health incidents, such as infectious disease outbreaks, severe weather events, chemical spills, and bioterrorism threats. We collected highly structured data on key aspects of the incident and the public health response, particularly focusing on the public health activities initiated and community partners engaged in the response efforts. As a result, we are able to make comparisons across event types, create response profiles, and identify functional and structural response patterns that have import for future public health preparedness and response. Our study contributes to clarifying the complexity of public health response systems and our analysis reveals the ways in which these systems are adaptive to the character of the threat, resulting in differential activation of functions and partners based on the type of incident. Continued and rigorous examination of the experiences of health departments throughout the nation will refine our very understanding of what the public health response system is, will enable the identification of organizational and event inputs to performance, and will allow for the construction of rich, relevant, and practical models of response operations that can be employed to strengthen public health systems.

Local Public Health System Response to the Tsunami Threat in Coastal California following the Tōhoku Earthquake

Background On Friday March 11, 2011 a 9.0 magnitude earthquake triggered a tsunami off the eastern coast of Japan, resulting in thousands of lives lost and billions of dollars in damage around the Pacific Rim. The tsunami first reached the California coast on Friday, March 11th, causing more than $70 million in damage and at least one death. While the tsunami's impact on California pales in comparison to the destruction caused in Japan and other areas of the Pacific, the event tested emergency responders' ability to rapidly communicate and coordinate a response to a potential threat. Methods To evaluate the local public health system emergency response to the tsunami threat in California, we surveyed all local public health, emergency medical services (EMS), and emergency management agencies in coastal or floodplain counties about several domains related to the tsunami threat in California, including: (1) the extent to which their community was affected by the tsunami, (2) when and how they received notification of the event, (3) which public health response activities were carried out to address the tsunami threat in their community, and (4) which organizations contributed to the response. Public health activities were characterized using the Centers for Disease Control and Prevention (CDC) Public Health Preparedness Capabilities (PHEP) framework. Findings The tsunami's impact on coastal communities in California ranged widely, both in terms of the economic consequences and the response activities. Based on estimates from the National Oceanic and Atmospheric Administration (NOAA), ten jurisdictions in California reported tsunami-related damage, which ranged from $15,000 to $35 million. Respondents first became aware of the tsunami threat in California between the hours of 10:00pm Pacific Standard Time (PST) on Thursday March 10th and 2:00pm PST on Friday March 11th, a range of 16 hours, with notification occurring through both formal and informal channels. In response to this threat, the activities most commonly reported by the local government agencies included in this study were: emergency public information and warning, emergency operations coordination, and inter-organizational information sharing, which were reported by 86%, 75%, and 65% of all respondents, respectively. When looking at the distribution of responsibility, emergency management agencies were the most likely to report assuming a lead role in these common activities as well as those related to evacuation and community recovery. While activated less frequently, public health agencies carried out emergency response functions related to surveillance and epidemiology, environmental health, and mental health/psychological support. Both local public health and EMS agencies took part in mass care and medical material management activities. A large network of organizations contributed to response activities, with emergency management, law enforcement, fire, public health, public works, EMS, and media cited by more than half of respondents. Conclusions In response to the tsunami threat in California, we found that emergency management agencies assumed a lead role in the local response efforts. While public health and medical agencies played a supporting role in the response, they uniquely contributed to a number of specific activities. If the response to the recent tsunami is any indication, these support activities can be anticipated in planning for future events with similar characteristics to the tsunami threat. Additionally, we found that many respondents first learned of the tsunami through the media, rather than through rapid notification systems, which suggests that government agencies must continue to develop and maintain the ability to rapidly aggregate and analyze information in order to provide accurate assessments and guidance to a potentially well-informed public.

CITATION

Hunter JC, Crawley AW, Petrie M, Yang JE, Aragón TJ. Local Public Health System Response to the Tsunami Threat in Coastal California following the Tōhoku Earthquake. PLoS Currents Disasters. 2012 Jul 16.

Public health management of antiviral drugs during the 2009 H1N1 influenza pandemic: a survey of local health departments in California

BACKGROUND

The large-scale deployment of antiviral drugs from the Strategic National Stockpile during the 2009 H1N1 influenza response provides a unique opportunity to study local public health implementation of the medical countermeasure dispensing capability in a prolonged event of national significance. This study aims to describe the range of methods used by local health departments (LHDs) in California to manage antiviral activities and to gain a better understanding of the related challenges experienced by health departments and their community partners.

METHODS

This research employed a mixed-methods approach. First, a multi-disciplinary focus group of pandemic influenza planners from key stakeholder groups in California was convened in order to generate ideas and identify critical themes related to the local implementation of antiviral activities during the H1N1 influenza response. These qualitative data informed the development of a web-based survey, which was distributed to all 61 LHDs in California for the purpose of assessing the experiences of a representative sample of local health agencies in a large region.

RESULTS

Forty-four LHDs participated in this study, representing 72% of the local public health agencies in California. While most communities dispensed a modest number of publicly purchased antivirals, LHDs nevertheless drew on their previous work and engaged in a number of antiviral activities, including: acquiring, allocating, distributing, dispensing, tracking, developing guidance, and communicating to the public and clinical community. LHDs also identified specific antiviral challenges presented by the H1N1 pandemic, including: reconciling multiple sources and versions of antiviral guidance, determining appropriate uses and recipients of publicly purchased antivirals, and staffing shortages.

CONCLUSIONS

The 2009 H1N1 influenza pandemic presented an unusual opportunity to learn about the role of local public health in the management of antiviral response activities during a real public health emergency. Results of this study offer an important descriptive account of LHD management of publicly purchased antivirals, and provide practitioners, policy makers, and academics with a practice-based assessment of these events. The issues raised and the challenges faced by LHDs should be leveraged to inform public health planning for future pandemics and other emergency events that require medical countermeasure dispensing activities.

At the crossroads: development and evaluation of a dementia caregiver group intervention to assist in driving cessation

Deciding when an individual with dementia must reduce or stop driving can be a stressful issue for family caregivers. The purpose of this study was to develop a group intervention to assist these caregivers with driving issues and to provide a preliminary evaluation of the comparative effectiveness of this At the Crossroads intervention. Participants were randomized to one of three arms: (1) active intervention (four 2-hour manualized educational/support group meetings; n = 31); (2) written materials only (participants received written materials after a pretest; n = 23); and (3)control (participants received written materials after a posttest; n = 12).Participants were administered a battery of self-report and interview-based questionnaires at baseline and again 2 months later. At follow-up, the active intervention group scored significantly better than both other groups on key outcome variables, including self-efficacy, communication, and preparedness. The At the Crossroads caregiver intervention appears to effectively provide education and support needed for caregivers to address driving-related issues with their loved ones.

Impaired osteoinduction in a rat model for chronic alcohol abuse

Alcohol abuse is a risk factor for bone fractures. Following a fracture, alcoholics have a higher risk for impaired fracture healing. However, the specific alcohol-induced defect(s) in bone healing are not known. Alcohol is a potent inhibitor of bone formation during bone growth and turnover. Thus, the purpose of this study was to determine the effects of alcohol consumption on induction of new bone formation. Demineralized allogeneic bone matrix (DABM) cylinders were used to model osteoinduction in a rat model for chronic alcohol abuse. DABM cylinders, prepared from femurs and tibiae of rats fed a normal diet, were implanted into sexually mature male rats adapted to alcohol (ethanol contributed 35% of caloric intake) or control liquid diets. Food intake in the control rats was restricted to match food intake of alcohol-fed animals. The implants were recovered 6 weeks later and analyzed by histology, muCT and chemical analysis. Histological evaluation revealed a robust osteoinductive response, resulting in mature bone ossicle formation, in DABM implants in rats fed the control diet. Alcohol consumption affected bone mass and architecture of the DABM implants but not volumetric density or mineral composition. Specifically, alcohol consumption resulted in significant decreases in DABM-induced bone volume, bone volume/mg original cylinder weight, connectivity density, trabecular number and thickness, ash weight and % ash weight. There were no changes in mineral (ash) density nor in the relative amounts of calcium, magnesium, iron, selenium and zinc (microg/mg ash), indicating that alcohol consumption did not impair mineralization. Taken together, these results show that alcohol abuse resulted in decreased bone formation within the DABM implant. We conclude that reduced osteoinduction may contribute to impaired bone healing in alcoholics.

Estrogen deficiency decreases ischemic tolerance in the aged rat heart: roles of PKCδ, PKCε, Akt, and GSK3β

The mechanisms underlying the age-dependent reversal of female cardioprotection are poorly understood and complicated by findings that estrogen replacement is ineffective at reducing cardiovascular mortality in postmenopausal women. Although several protective signals have been identified in young animals, including PKC and Akt, how these signals are affected by age, estrogen deficiency, and ischemia-reperfusion (I/R) remains unknown. To determine the independent and combined effects of age and estrogen deficiency on I/R injury and downstream PKC-Akt signaling, adult and aged female F344 rats ( n = 12/age) with ovaries intact or ovariectomy (Ovx) were subjected to I/R using Langendorff perfusion (31-min global-ischemia). Changes in cytosolic (s), nuclear (n), mitochondrial (m) PKC (δ, ε) levels, and changes in total Akt and mGSK-3β phosphorylation after I/R were assessed by Western blot analysis. Senescence increased infarct size 50% in ovary-intact females ( P < 0.05), whereas no differences in LV functional recovery or estradiol levels were observed. Ovx reduced functional recovery to a greater extent in aged compared with adult rats ( P < 0.05). In aged (vs. adult), levels of m- and nPKC(-δ, -ε) were markedly decreased, whereas mGSK3β levels were increased ( P < 0.05). Ovx led to greater levels of sPKC(-δ, -ε) independent of age ( P < 0.05). I/R reduced p-Akt(Ser473) levels by 57% and increased mGSK-3β accumulation 1.77-fold ( P < 0.05) in aged, ovary-intact females. These data suggest, for the first time, that estrogen alone cannot protect the aged female myocardium from I/R damage and that age- and estrogen-dependent alterations in PKC, Akt, and GSK-3β signaling may contribute to loss of ischemic tolerance.

The antidepressant-like effects of neurokinin NK1 receptor antagonists in a gerbil tail suspension test

Recent clinical evidence supports the potential of neurokinin NK1 receptor antagonists as novel antidepressant drugs. A number of NK1 antagonists have reduced affinity for rat and mouse NK1 receptors compared to human, making it difficult to test for efficacy in traditional animal models. NK1 antagonists, in general, have similar affinity at gerbil and human NK1 receptors. The aims of these studies were first, to validate the gerbil tail suspension test, a test used frequently to demonstrate antidepressant drug efficacy in mice, and second, to determine whether the test could be used to demonstrate the antidepressant potential of NK1 antagonists. Immobility time was reduced by oral administration of the antidepressants imipramine (3-30 mg/kg), desipramine (1-30 mg/kg), amitriptyline (30 mg/kg), fluoxetine (1-30 mg/kg), paroxetine (3-10 mg/kg), citalopram (0.1-3 mg/kg), sertraline (1-30 mg/kg), venlafaxine (1-30 mg/kg) and nefazodone (100 mg/kg). Furthermore, oral administration of the NK1 antagonists MK-869 (10 mg/kg), L-742694 (10 mg/kg), L-733060 (10 mg/kg), CP-99994 (30 mg/kg), and CP-122721 (3-30 mg/kg) reduced immobility time. Diazepam (1-10 mg/kg), chlordiazepoxide (1-10 mg/kg), buspirone (3-30 mg/kg), FG-7142 (1-30 mg/kg), and haloperidol (1-10 mg/kg) did not reduce immobility. Amphetamine (0.3-10 mg/kg) and atropine (0.3-10 mg/kg) reduced immobility, suggesting susceptibility to false positives, e.g. compounds that affect locomotion. Compounds were therefore tested in a gerbil locomotor activity (LMA) test to ensure that the antidepressant-like effects were not secondary to effects on activity. Antidepressant drugs and NK1 antagonists had no effect on LMA at doses that reduced immobility, whereas amphetamine and atropine induced marked hyperactivity. These studies support both the utility of gerbils in behavioral pharmacology and the antidepressant potential of selective NK1 antagonists.

Differential pattern of expression of voltage-gated sodium channel genes following ischemic brain injury in rats

This study investigated the effects of brain ischemia on sodium channel gene (NaCh) expression in rats. Using quantitative RT-PCR, our findings demonstrated the expression ratio of NaCh genes in normal rat brain to be Na(v)1.1 > Na(v)1.8 > Na(v)1.3 > Na(v)1.7 (rBI > PN3 > rBIII > PN1). In contrast, brain injury caused by middle cerebral artery occlusion (MCAo) for 2 h followed by reperfusion significantly down-regulated Na(v)1.3 and Na(v)1.7 genes in both injured and contralateral hemispheres; whereas the Na(v)1.8 gene was down regulated in only the injured hemisphere (though only acutely at 2 or 2-6 h post-MCAo). However, the time-course of NaCh gene expression revealed a significant down-regulation of Na(v)1.1 only in the ischemic hemisphere beginning 6 h post-MCAo and measured out to 48 h post-MCAo. In a separate preliminary study Na(v)1.2 (rBII) gene was found to be expressed at levels greater than that of Na(v)1.1 in normal rats and was significantly down regulated at 24 h post-MCAo). Our findings document, for the first time, quantitative and relative changes in the expression of various NaCh genes following ischemic brain injury and suggest that the Na(v)1.1 sodium channel gene may play a key role in ischemic injury/recovery.

Regulation of Na+ channel distribution in the nervous system

An important aspect of Na+ channel regulation is their distribution on neuronal membranes within the nervous system. The complexity of this process is brought by the molecular diversity of Na+ channels and differential regulation of their distribution. In addition, Na+ channel localization is a highly dynamic process depending on the status of the cell in vitro, and (patho)physiological condition of the organism in vivo. Nonetheless, the pharmacological manipulation of Na+ channel distribution should be possible and will hopefully bring safer and more-potent medicines in the future.

Contribution of alpha(2) receptor subtypes to nerve injury-induced pain and its regulation by dexmedetomidine

There is evidence that noradrenaline contributes to the development and maintenance of neuropathic pain produced by trauma to a peripheral nerve. It is, however, unclear which subtype(s) of alpha adrenergic receptors (AR) may be involved. In addition to pro-nociceptive actions of AR stimulation, alpha(2) AR agonists produce antinociceptive effects. Here we studied the contribution of the alpha(2) AR subtypes, alpha(2A), alpha(2B) and alpha(2C) to the development of neuropathic pain. We also examined the antinociceptive effect produced by the alpha(2) AR agonist dexmedetomidine in nerve-injured mice. The studies were performed in mice that carry either a point (alpha(2A)) or a null (alpha(2B) and alpha(2C)) mutation in the gene encoding the alpha(2) AR. To induce a neuropathic pain condition, we partially ligated the sciatic nerve and measured changes in thermal and mechanical sensitivity. Baseline mechanical and thermal withdrawal thresholds were similar in all mutant and wild-type mice; and, after peripheral nerve injury, all mice developed comparable hypersensitivity (allodynia) to thermal and mechanical stimulation. Dexmedetomidine reversed the allodynia at a low dose (3 microg kg(-1), s.c.) and produced antinociceptive effects at higher doses (10 - 30 microg kg(-1)) in all groups except in alpha(2A) AR mutant mice. The effect of dexmedetomidine was reversed by intrathecal, but not systemic, injection of the alpha(2) AR antagonist RS 42206. These results suggest that neither alpha(2A), alpha(2B) nor alpha(2C) AR is required for the development of neuropathic pain after peripheral nerve injury, however, the spinal alpha(2A) AR is essential for the antinociceptive effects of dexmedetomidine.

Differential distribution of the tetrodotoxin-sensitive rPN4/NaCh6/Scn8a sodium channel in the nervous system

Voltage-gated sodium channels underlie the generation of action potentials in excitable cells. Various sodium channel isoforms have been cloned, functionally expressed and distinguished on the basis of their biophysical properties or differential sensitivity to tetrodotoxin (TTX). In the present study, we have investigated the immunolocalization of the TTX-sensitive sodium channel, rPN4/NaCh6/Scn8a, in discrete areas of the rat nervous system. Thus, in naïve animals, PN4 was abundantly expressed in brain, spinal cord, dorsal root ganglia (DRG) and peripheral nerve. The presence of PN4 at the nodes of Ranvier in the sciatic nerve suggests the importance of this sodium channel in peripheral nerve conduction. In addition, the pattern of PN4 immunolabeling was determined in DRG, spinal cord and sciatic nerve in rats subjected to chronic constriction nerve injury (CCI).

Ions in the fire: recent ion-channel research and approaches to pain therapy

Ion channels form a diverse and sophisticated collection of membrane-bound proteins. They are influenced by many endogenous compounds and physiological stimuli and modulate neuronal activity. It is thus not surprising that they provide attractive targets for the design of novel therapeutics. In this article, recent ion channel research and its relevance to modulation of sensory transmission is assessed. In pain research, specific blockade or activation of ion channels has long been considered a desired route for identification of analgesics. Historically, this has proven difficult to attain due to the incidence of side-effects associated with most ion-channel modulators. The recent discovery of several novel classes of ion channels, each of which has a specific distribution and role in sensory processing and nociception, has provided a plethora of targets for pharmaceutical intervention with the promise of an improved therapeutic index.

A comparison of the potential role of the tetrodotoxin-insensitive sodium channels, PN3/SNS and NaN/SNS2, in rat models of chronic pain

Alterations in sodium channel expression and function have been suggested as a key molecular event underlying the abnormal processing of pain after peripheral nerve or tissue injury. Although the relative contribution of individual sodium channel subtypes to this process is unclear, the biophysical properties of the tetrodotoxin-resistant current, mediated, at least in part, by the sodium channel PN3 (SNS), suggests that it may play a specialized, pathophysiological role in the sustained, repetitive firing of the peripheral neuron after injury. Moreover, this hypothesis is supported by evidence demonstrating that selective "knock-down" of PN3 protein in the dorsal root ganglion with specific antisense oligodeoxynucleotides prevents hyperalgesia and allodynia caused by either chronic nerve or tissue injury. In contrast, knock-down of NaN/SNS2 protein, a sodium channel that may be a second possible candidate for the tetrodotoxin-resistant current, appears to have no effect on nerve injury-induced behavioral responses. These data suggest that relief from chronic inflammatory or neuropathic pain might be achieved by selective blockade or inhibition of PN3 expression. In light of the restricted distribution of PN3 to sensory neurons, such an approach might offer effective pain relief without a significant side-effect liability.

RESEARCH: Prospects for Preservation and Restoration of Riparian Forests in the Sacramento Valley, California, USA

/ This GIS-based study analyzes the distribution and management of woody riparian vegetation in California's Sacramento Valley and discusses the prospects for its conservation. Although forests were the predominant floodplain vegetation prior to extensive settlement, only 3.3% of floodplain was covered by forest in the late 1980s. This remaining forest was fragmented into 2607 patches with an average area of 3.1 ha. Only 180 patches were >10 ha, with three patches >100 ha. Despite over two decades of conservation efforts, these forests are essentially unpreserved: Only 14.5% of extant forests are in public ownership or on land managed primarily for biological conservation. Some privately owned forests represent opportunities for preservation, but owing to their small size and scattered distribution, reforestation would be necessary to obtain a high cover of forest over large areas. Additionally, high property values, existing land uses, and regulated hydrology constrain conservation efforts. As a consequence of these constraints, and current distribution and ownership patterns, preservation or restoration of substantial areas of riparian forest would be extremely expensive and would divert conservation resources from other habitats in this rapidly developing state. Therefore, efforts to conserve these forests should satisfy two criteria: (1) that the specific goals are attainable with available funding and existing human uses, and (2) funding the effort will result in more effective regional conservation than would funding the conservation of other habitats.KEY WORDS: Central Valley; Conservation; Floodplains; Geographic information systems; Riparian vegetationhttp://link.springer-ny.com/link/service/journals/00267/bibs/24n1p65.html

Cervical spine tomography with an angiographic C-arm

Phantom studies were performed to develop a technique for linear tomography of the craniocervical junction with a digital fluoroscopic angiographic C-arm unit. Section thicknesses were similar to those used at conventional tomography, and the radiation dose was lower. C-arm tomography was possible with a 6-second exposure and a 40 degrees arc. C-arm tomography is a practical method for decreasing patient turnaround time.

Immunocytochemical localization of P2X3 purinoceptors in sensory neurons in naive rats and following neuropathic injury

P2X3 purinoceptor cellular distribution was studied in rat sensory neurons in naive animals and following peripheral nerve injury using immunohistochemical methods. Specific antiserum was raised in rabbits and characterized by Western blot, absorption assays and labeling of recombinant receptors. In naive animals, P2X3 immunoreactivity was present predominantly in a subpopulation of small-diameter sensory neurons in dorsal root ganglia. In the spinal cord, immunoreactivity was observed in the superficial laminae of the dorsal horn. Following a chronic constriction injury to the sciatic nerve, the number of P2X3 positive small and medium diameter neurons increased in dorsal root ganglia when compared with sham-operated animals. In addition, the spinal cord immunoreactivity increased in magnitude on the side ipsilateral to the ligated nerve, consistent with up-regulation of receptors in presynaptic terminals of the primary sensory neurons.

Characterization of the analgesic and anti-inflammatory activities of ketorolac and its enantiomers in the rat

The marked analgesic efficacy of ketorolac in humans, relative to other nonsteroidal anti-inflammatory drugs (NSAIDs), has lead to speculation as to whether additional non-NSAID mechanism(s) contribute to its analgesic actions. To evaluate this possibility, we characterized (R,S)-ketorolac's pharmacological properties in vivo and in vitro using the nonselective cyclooxygenase (COX) inhibitors [indomethacin (INDO) and diclofenac sodium (DS)] as well as the selective COX-2 inhibitor, celecoxib, as references. The potency of racemic (R,S)-ketorolac was similar in tests of acetic acid-induced writhing, carrageenan-induced paw hyperalgesia, and carrageenan-induced edema formation in rats; ID50 values = 0.24, 0. 29, and 0.08 mg/kg, respectively. (R,S)-ketorolac's actions were stereospecific, with (S)-ketorolac possessing the biological activity of the racemate in the above tests. The analgesic potencies for (R,S)-, (S)-, and (R)-ketorolac, INDO, and DS were highly correlated with their anti-inflammatory potencies, suggesting a common mechanism. (R,S)-ketorolac was significantly more potent than INDO or DS in vivo. Neither difference in relative potency of COX inhibition for (R,S)-ketorolac over INDO and DS nor activity of (S)-ketorolac at a number of other enzymes, channels, or receptors could account for the differences in observed potency. The distribution coefficient for (R,S)-ketorolac was approximately 30-fold less than for DS or INDO, indicating that (R,S)-ketorolac is much less lipophilic than these NSAIDs. Therefore, the physicochemical and pharmacokinetics properties of (R,S)-ketorolac may optimize the concentrations of (S)-ketorolac at its biological target(s), resulting in greater efficacy and potency in vivo.

Functional analysis of a voltage-gated sodium channel and its splice variant from rat dorsal root ganglia

Neurons of the dorsal root ganglia (DRG) express a diversity of voltage-gated sodium channels. From rat DRG we have cloned and functionally expressed a tetrodotoxin-sensitive sodium channel alpha subunit, NaCh6/Scn8a/rPN4, and a splice variant, rPN4a. Primary structure analysis shows NaCh6/Scn8a/rPN4 to be highly homologous (99%) to NaCh6 and most likely represents the same transcript. The splice variation in rPN4a is homologous in sequence and location to that of rat brain I. Tissue distribution analyzed by RT-PCR showed NaCh6/Scn8a/rPN4 to be expressed at its highest levels in rat brain, at moderate levels in spinal cord, and at lower levels in DRG, nodose ganglia, and superior cervical ganglia and to be absent from sciatic nerve, heart, and skeletal muscle. In contrast, rPN4a shows no expression in brain and low-level expression in spinal cord, whereas in DRG its expression is comparable to that of NaCh6/Scn8a/rPN4. Functional analysis of these channels expressed in Xenopus oocytes showed that NaCh6/Scn8a/rPN4 and rPN4a exhibited similar properties, with V(1/2) approximately -100 mV for steady-state inactivation and V(1/2) approximately -40 mV for activation. rPN4a recovered from inactivation significantly faster than NaCh6/Scn8a/rPN4. NaCh6/Scn8a/rPN4 was inhibited by tetrodotoxin with an IC50 approximately 1 nM. Coexpression of the beta1 subunit accelerated inactivation kinetics, but the beta2 subunit was without effect.

Characterization of prostanoid receptor-evoked responses in rat sensory neurones

1. Prostanoid receptor-mediated sensitization, or excitation, of sensory nerve fibres contributes to the generation of hyperalgesia. To characterize the prostanoid receptors present on sensory neurones, biochemical assays were performed on primary cultures of adult rat dorsal root ganglia (DRG) and the F-11 (embryonic rat DRG x neuroblastoma hybrid) cell line. 2. In DRG cultures, the IP receptor agonists, cicaprost and carbaprostacyclin (cPGI2) stimulated cyclic AMP accumulation. Prostaglandin E2 (PGE2) also increased cyclic AMP levels, but to a lesser extent, while carbocyclic thromboxane A2 (cTxA2), PGD2 and PGF2alpha had negligible effects. The rank order of agonist potency was cicaprost>PGE2=BMY45778=cPGI2=PGI2. In the F-11 cells, the rank order of agonist potency for the stimulation of cyclic AMP accumulation was: cicaprost>iloprost=cPGI2=PGI2=BMY45778>PGE2=cTXA2++ +. In DRG cultures, cicaprost induced significantly more accumulation of inositol phosphates than PGE2. 3. To examine the effects of prostanoids on C-fibre activity, extracellular recordings of d.c. potentials from the rat isolated vagus nerve were made with the 'grease-gap' technique. PGI2 (0.1 nM-10 microM) produced the largest depolarizations of the nerve. The rank order of agonist potency was: PGI2=cPGI2=PGE1>cTXA2>PGE2=PGD2=TXB2>PGF2alpha. 4. Prior depolarization of nerves with either forskolin (10 microM) or phorbol dibutyrate (1 microM) alone significantly reduced the response to PGI2 (10 microM), while simultaneous application of both forskolin and phorbol dibutyrate attenuated PGI2 responses almost completely. 5. Putative EP1 and/or TP receptor-selective antagonists had no effect on the responses to PGI2, cPGI2 or PGE2 in the three preparations studied. 6. Collectively, these data are consistent with a positive coupling of IP receptors to both adenylyl cyclase and phospholipase C in sensory neurones. These findings suggest that IP receptors play a major role in the sensitization of rat sensory neurones.

The role of IP prostanoid receptors in inflammatory pain

Prostanoid receptor-mediated sensitization of sensory nerve fibres is a key contributor to the generation of hyperalgesia. It is generally thought that prostaglandin (PG) E2 is the principal pro-inflammatory prostanoid. Consequently, prostanoid EP receptors on sensory neurones have been identified as potential therapeutic targets. However, IP prostanoid receptors are also present on sensory neurones, and recent data from transgenic mice lacking the IP receptor demonstrate its importance in the induction of oedema and pain behaviour. PGI2, the primary endogenous agonist for the IP receptor, is rapidly produced following tissue injury or inflammation; thus, it may be of equal, or greater, importance than PGE2 during episodes of inflammatory pain. In this review, Keith Bley, John Hunter, Richard Eglen and Jacqueline Smith compare the roles of EP and IP receptors in nociception and suggest that the IP receptor constitutes a novel target for anti-nociceptive agents.

Distribution of the tetrodotoxin-resistant sodium channel PN3 in rat sensory neurons in normal and neuropathic conditions

The novel sodium channel PN3/alpha-SNS, which was cloned from a rat dorsal root ganglion (DRG) cDNA library, is expressed predominantly in small sensory neurons and may contribute to the tetrodotoxin-resistant (TTXR) sodium current that is believed to be associated with central sensitization in chronic neuropathic pain states. To assess further the role of PN3, we have used electrophysiological, in situ hybridization and immunohistochemical methods to monitor changes in TTXR sodium current and the distribution of PN3 in normal and peripheral nerve-injured rats. (1) Whole-cell patch-clamp recordings showed that there were no significant changes in the TTXR and TTX-sensitive sodium current densities of small DRG neurons after chronic constriction injury (CCI) of the sciatic nerve. (2) Additionally, in situ hybridization showed that there was no change in the expression of PN3 mRNA in the DRG up to 14 d after CCI. PN3 mRNA was not detected in sections of brain and spinal cord taken from either normal or nerve-injured rats. (3) In contrast, immunohistochemical studies showed that major changes in the subcellular distribution of PN3 protein were caused by either CCI or complete transection of the sciatic nerve. The intensity of PN3 immunolabeling decreased in small DRG neurons and increased in sciatic nerve axons at the site of injury. The alteration in immunolabeling was attributed to translocation of presynthesized, intracellularly located PN3 protein from neuronal somata to peripheral axons, with subsequent accumulation at the site of injury. The specific subcellular redistribution of PN3 after peripheral nerve injury may be an important factor in establishing peripheral nerve hyperexcitability and resultant neuropathic pain.