Climate Change and the Epidemiology of Infectious Diseases in the United States.

The earth is rapidly warming, driven by increasing atmospheric carbon dioxide and other gases that result primarily from fossil fuel combustion. In addition to causing arctic ice melting and extreme weather events, climatologic factors are linked strongly to the transmission of many infectious diseases. Changes in the prevalence of infectious diseases not only reflect the impacts of temperature, humidity, and other weather-related phenomena on pathogens, vectors, and animal hosts but are also part of a complex of social and environmental factors that will be affected by climate change, including land use, migration, and vector control. Vector- and waterborne diseases and coccidioidomycosis are all likely to be affected by a warming planet; there is also potential for climate-driven impacts on emerging infectious diseases and antimicrobial resistance. Additional resources for surveillance and public health activities are urgently needed, as well as systematic education of clinicians on the health impacts of climate change.

Reduction in Clostridium difficile infection rates following a multifacility prevention initiative in Orange County, California: A controlled interrupted time series evaluation.

OBJECTIVE: To evaluate the Orange County Clostridium difficile infection (CDI) prevention collaborative's effect on rates of CDI in acute-care hospitals (ACHs) in Orange County, California. DESIGN: Controlled interrupted time series. METHODS: We convened a CDI prevention collaborative with healthcare facilities in Orange County to reduce CDI incidence in the region. Collaborative participants received onsite infection control and antimicrobial stewardship assessments, interactive learning and discussion sessions, and an interfacility transfer communication improvement initiative during June 2015-June 2016. We used segmented regression to evaluate changes in monthly hospital-onset (HO) and community-onset (CO) CDI rates for ACHs. The baseline period comprised 17 months (January 2014-June 2015) and the follow-up period comprised 28 months (September 2015-December 2017). All 25 Orange County ACHs were included in the CO-CDI model to account for direct and indirect effects of the collaborative. For comparison, we assessed HO-CDI and CO-CDI rates among 27 ACHs in 3 San Francisco Bay Area counties. RESULTS: HO-CDI rates in the 15 participating Orange County ACHs decreased 4% per month (incidence rate ratio [IRR], 0.96; 95% CI, 0.95-0.97; P < .0001) during the follow-up period compared with the baseline period and 3% (IRR, 0.97; 95% CI, 0.95-0.99; P = .002) per month compared to the San Francisco Bay Area nonparticipant ACHs. Orange County CO-CDI rates declined 2% per month (IRR, 0.98; 95% CI, 0.96-1.00; P = .03) between the baseline and follow-up periods. This decline was not statistically different from the San Francisco Bay Area ACHs (IRR, 0.97; 95% CI, 0.95-1.00; P = .09). CONCLUSIONS: Our analysis of ACHs in Orange County provides evidence that coordinated, regional multifacility initiatives can reduce CDI incidence.

Outbreak of Foodborne Botulism Associated With Prepackaged Pouches of Liquid Herbal Tea.

BACKGROUND: In 2017, local public health authorities in California received reports of 2 elderly patients with suspected botulism who knew each other socially. A multijurisdictional investigation was conducted to determine the source. METHODS: Investigators reviewed medical records, interviewed family to establish food and drink histories, and inspected a facility that produced liquid herbal tea. Clinical specimens and product were tested for botulinum neurotoxin (BoNT). RESULTS: A total of 2 confirmed botulism cases were identified with BoNT type A; both were hospitalized, 1 died. Botulism was not suspected until several days after hospital admission. Case-patients ingested single-serving prepackaged liquid herbal tea. Inspection of the tea production facility identified conditions conducive to product contamination with C botulinum and toxin production. Samples of tea tested negative for botulinum toxin. Local and state public health authorities issued alerts and the facility recalled the liquid herbal tea. CONCLUSIONS: Liquid herbal tea prepackaged in sealed pouches was the likely source of this type A botulism outbreak because the 2 cases were linked socially and shared no other foods. This type of product has not previously been described in the foodborne botulism literature. In the absence of known risk factors for botulism at the time of presentation, suspicion based on clinically compatible findings is critical so that and treatment with botulinum antitoxin is not delayed. A coordinated response by public health authorities is necessary in identifying a potential food source, inspecting facilities producing the product, alerting medical providers and the public, and preventing further illness.

Hepatitis B Virus Mutant Infections in Hemodialysis Patients: A Case Series.

RATIONALE & OBJECTIVE: Hepatitis B virus (HBV) transmission in hemodialysis units has become a rare event since implementation of hemodialysis-specific infection control guidelines: performing hemodialysis for hepatitis B surface antigen (HBsAg)-positive patients in an HBV isolation room, vaccinating HBV-susceptible (HBV surface antibody and HBsAg negative) patients, and monthly HBsAg testing in HBV-susceptible patients. Mutations in HBsAg can result in false-negative HBsAg results, leading to failure to identify HBsAg seroconversion from negative to positive. We describe 4 unique cases of HBsAg seroconversion caused by mutant HBV infection or reactivation in hemodialysis patients. STUDY DESIGN: Following identification of a possible HBsAg seroconversion and mutant HBV infection, public health investigations were launched to conduct further HBV testing of case patients and potentially exposed patients. A case patient was defined as a hemodialysis patient with suspected mutant HBV infection because of false-negative HBsAg testing results. Confirmed case patients had HBV DNA sequences demonstrating S-gene mutations. SETTING & PARTICIPANTS: Case patients and patients potentially exposed to the case patient in the respective hemodialysis units in multiple US states. RESULTS: 4 cases of mutant HBV infection in hemodialysis patients were identified; 3 cases were confirmed using molecular sequencing. Failure of some HBsAg testing platforms to detect HBV mutations led to delays in applying HBV isolation procedures. Testing of potentially exposed patients did not identify secondary transmissions. LIMITATIONS: Lack of access to information on past HBsAg testing platforms and results led to challenges in ascertaining when HBsAg seroconversion occurred and identifying and testing all potentially exposed patients. CONCLUSIONS: Mutant HBV infections should be suspected in patients who test HBsAg negative and concurrently test positive for HBV DNA at high levels. Dialysis providers should consider using HBsAg assays that can also detect mutant HBV strains for routine HBV testing.

Clinical Characteristics of Measles in Previously Vaccinated and Unvaccinated Patients in California.

Background: Measles vaccine failure was first described in 1972. Over the next 20 years, vaccine failure was extensively studied, but during the last 25 years few investigations have been performed. We describe the clinical characteristics of measles in previously vaccinated and unvaccinated patients in California. Methods: All confirmed measles cases reported to the California Department of Public Health from 1 January 2000 through 31 December 2015 were reviewed. Clinical characteristics (rates of hospitalization, cough, coryza, conjunctivitis, and fever) were compared between the previously unvaccinated, those who had had 1 dose of vaccine, and those who had had ≥2 doses of measles vaccine. Results: There were 232 confirmed measles cases in whom vaccination status was verified; 80% were unvaccinated, 9% had had 1 dose of measles vaccine, and 11% had had ≥2 doses of measles vaccine. Subjects who had had ≥2 doses of measles vaccine had lower rates of hospitalization, cough, coryza, conjunctivitis, and fever than subjects who had 1 dose of measles vaccine or who were unimmunized. Conclusions: Vaccine failure measles cases were less ill than cases that occurred in unvaccinated patients. Nevertheless, these cases still required the same amount of public health effort in tracing contacts as in cases who were unvaccinated.

Outbreak of Serogroup C Meningococcal Disease Primarily Affecting Men Who Have Sex with Men - Southern California, 2016.

During March 4-August 11, 2016, 25 outbreak-associated cases of meningococcal disease, including two deaths (8% case-fatality ratio), were reported in Southern California. Twenty-four of the cases were caused by serogroup C Neisseria meningitidis (NmC) and one by N. meningitidis with an undetermined serogroup (Figure). On June 24, 2016, in response to this increase in NmC cases, primarily among men who have sex with men (MSM) in Los Angeles County, the city of Long Beach, and Orange County, the California Department of Public Health (CDPH) issued a press release and health advisory, declaring an outbreak of NmC in Southern California (1).

Just when you think you know someone: the evolving epidemiologies of measles and pertussis.

PURPOSE OF REVIEW: The epidemiologic patterns of measles and pertussis continue to evolve in the United States. Recent studies have provided important insights which impact the public health response to these diseases. RECENT FINDINGS: An increase in imported cases has led to increased reports of measles disease in the United States. The burden of pertussis disease is shifting to schoolchildren who have received only acellular vaccinations as part of their childhood series. SUMMARY: Routine childhood vaccinations protect against these diseases, but have limitations which should be recognized. Medical providers and public health practitioners will need to work together to ensure that patients are educated about the importance of vaccines, and that these vaccines are available to those who need them.

Self-immunization with live attenuated influenza vaccine in a mass vaccination clinic.

OBJECTIVE: An influenza pandemic may demand that a large number of influenza immunizations be rapidly given with limited resources. This study tested the utility and practicality of self-immunization with live attenuated influenza intranasal vaccine in a mass vaccination event. METHODS: The self-immunization clinic model was evaluated in a three-tiered fashion using student, first responder, and open community events. RESULTS: A single nurse was easily able to direct 89 people through the process of self-administration of the vaccine in a three-hour first-responder event and 122 people in a three-hour open community event. 96% of participants believed that they had performed the self-administration correctly, and the same percentage reported that they would like to receive influenza immunization by self-vaccination in the future. CONCLUSIONS: The self-immunization clinic is a practical and potentially useful model in an influenza pandemic setting.

Granulomatous pleuritis caused by histoplasmosis in a healthy child.

Pneumonia with pleuritis is a rare presentation of histoplasmosis infection. We present a 12-year old previously healthy boy in whom histoplasmosis presented with pleuritis, confirmed by detection of antigen in empyema fluid.

Culture negative endocarditis caused by Bartonella henselae in a child with congenital heart disease.

A 9-year-old white male with congenital aortic and subaortic stenosis palliated by the Ross-Konno procedure presented with culture-negative endocarditis. Serologic studies and polymerase chain reaction testing of resected homograft valvular tissue provided evidence of Bartonella henselae as the etiology. B. henselae can cause endocarditis in children, particularly those with underlying valvular disease. Serologic testing for B. henselae should be considered in children with culture-negative endocarditis.

Clinical and epidemiological aspects of rotavirus infection.

Rotavirus is a major worldwide cause of infant morbidity and mortality, and disease burden in the US is substantial. Vaccination is the only practical way to gain control over rotavirus disease. Prevention through the universal use of improved live oral vaccines is on the horizon.

Host cell lipids control cholesteryl ester synthesis and storage in intracellular Toxoplasma.

The intracellular protozoan Toxoplasma gondii lacks a de novo mechanism for cholesterol synthesis and therefore must scavenge this essential lipid from the host environment. In this study, we demonstrated that T. gondii diverts cholesterol from low-density lipoproteins for cholesteryl ester synthesis and storage in lipid bodies. We identified and characterized two isoforms of acyl-CoA:cholesterol acyltransferase (ACAT)-related enzymes, designated TgACAT1alpha and TgACAT1beta in T. gondii. Both proteins are coexpressed in the parasite, localized to the endoplasmic reticulum and participate in cholesteryl ester synthesis. In contrast to mammalian ACAT, TgACAT1alpha and TgACAT1beta preferentially incorporate palmitate into cholesteryl esters and present a broad sterol substrate affinity. Mammalian ACAT-deficient cells transfected with either TgACAT1alpha or TgACAT1beta are restored in their capability of cholesterol esterification. TgACAT1alpha produces steryl esters and forms lipid bodies after transformation in a Saccharomyces cerevisiae mutant strain lacking neutral lipids. In addition to their role as ACAT substrates, host fatty acids and low-density lipoproteins directly serve as Toxoplasma ACAT activators by stimulating cholesteryl ester synthesis and lipid droplet biogenesis. Free fatty acids significantly increase TgACAT1alpha mRNA levels. Selected cholesterol esterification inhibitors impair parasite growth by rapid disruption of plasma membrane. Altogether, these studies indicate that host lipids govern neutral lipid synthesis in Toxoplasma and that interference with mechanisms of host lipid storage is detrimental to parasite survival in mammalian cells.