Molecular Epidemiology of Measles in California, United States-2019.

In 2019, the United States (US) experienced the highest number of measles importations and cases in the postelimination era. More than a quarter of imported cases entered the US through California. Measles surveillance efforts in California resulted in the identification of 26 importations, 6 outbreaks, and 72 cases in 2019. Only genotype B3 and D8 measles strains were detected. Genotype-specific differences were noted in the incidence of vaccine failures, hospitalizations, and severe complications among cases. A targeted whole genome sequencing approach provided higher-resolution discrimination between epidemiologically linked and sporadically introduced strains than conventional N450 sequencing. Our report underscores the importance of ensuring appropriate measles vaccination status, especially prior to international travel to measles-endemic regions, and highlights the value of a strong measles surveillance system in minimizing outbreaks and preserving measles elimination status in the US.

Public Health Responses to COVID-19 Outbreaks on Cruise Ships - Worldwide, February-March 2020.

An estimated 30 million passengers are transported on 272 cruise ships worldwide each year* (1). Cruise ships bring diverse populations into proximity for many days, facilitating transmission of respiratory illness (2). SARS-CoV-2, the virus that causes coronavirus disease (COVID-19) was first identified in Wuhan, China, in December 2019 and has since spread worldwide to at least 187 countries and territories. Widespread COVID-19 transmission on cruise ships has been reported as well (3). Passengers on certain cruise ship voyages might be aged ≥65 years, which places them at greater risk for severe consequences of SARS-CoV-2 infection (4). During February-March 2020, COVID-19 outbreaks associated with three cruise ship voyages have caused more than 800 laboratory-confirmed cases among passengers and crew, including 10 deaths. Transmission occurred across multiple voyages of several ships. This report describes public health responses to COVID-19 outbreaks on these ships. COVID-19 on cruise ships poses a risk for rapid spread of disease, causing outbreaks in a vulnerable population, and aggressive efforts are required to contain spread. All persons should defer all cruise travel worldwide during the COVID-19 pandemic.

Pan-viral serology implicates enteroviruses in acute flaccid myelitis.

Since 2012, the United States of America has experienced a biennial spike in pediatric acute flaccid myelitis (AFM)1-6. Epidemiologic evidence suggests non-polio enteroviruses (EVs) are a potential etiology, yet EV RNA is rarely detected in cerebrospinal fluid (CSF)2. CSF from children with AFM (n = 42) and other pediatric neurologic disease controls (n = 58) were investigated for intrathecal antiviral antibodies, using a phage display library expressing 481,966 overlapping peptides derived from all known vertebrate and arboviruses (VirScan). Metagenomic next-generation sequencing (mNGS) of AFM CSF RNA (n = 20 cases) was also performed, both unbiased sequencing and with targeted enrichment for EVs. Using VirScan, the viral family significantly enriched by the CSF of AFM cases relative to controls was Picornaviridae, with the most enriched Picornaviridae peptides belonging to the genus Enterovirus (n = 29/42 cases versus 4/58 controls). EV VP1 ELISA confirmed this finding (n = 22/26 cases versus 7/50 controls). mNGS did not detect additional EV RNA. Despite rare detection of EV RNA, pan-viral serology frequently identified high levels of CSF EV-specific antibodies in AFM compared with controls, providing further evidence for a causal role of non-polio EVs in AFM.

Laboratory Testing for Middle East Respiratory Syndrome Coronavirus, California, USA, 2013-2014.

Since Middle East respiratory syndrome coronavirus (MERS-CoV) first emerged, the California Department of Public Health has coordinated efforts to identify possible cases in travelers to California, USA, from affected areas. During 2013-2014, the department investigated 54 travelers for MERS-CoV; none tested positive, but 32 (62%) of 52 travelers with suspected MERS-CoV had other respiratory viruses.

Missed opportunities for tetanus postexposure prophylaxis--California, January 2008-March 2014.

Tetanus is an acute and sometimes fatal disease characterized by sudden muscle contractions. The number of tetanus cases reported annually in the United States has declined significantly since the 1930s and 1940s as a result of the introduction of tetanus vaccines. However, sporadic cases continue to occur in persons who are not up-to-date with tetanus toxoid-containing vaccinations (TT) and do not receive appropriate postexposure prophylaxis (PEP). To assess the extent of these cases, the California Department of Public Health reviewed all tetanus cases reported during January 2008-March 2014. A total of 21 tetanus patients were reported; five (24%) died. An average of three cases were reported each year during 2008-2013; the average annual incidence among patients aged ≥65 years (0.23 cases per 1 million population) was twice that among patients aged 21-64 years (0.10 cases per 1 million population). Of 16 patients with an acute injury before illness and diagnosis, nine (56%) sought medical care, and two (22%) of the nine received appropriate PEP. Although tetanus is rare, it is a life-threatening disease that is preventable. Health care providers should ensure that their patients are up-to-date with TT vaccination and provide appropriate postexposure prophylaxis for patients with wounds.

Acute flaccid paralysis with anterior myelitis - California, June 2012-June 2014.

In August 2012, the California Department of Public Health (CDPH) was contacted by a San Francisco Bay area clinician who requested poliovirus testing for an unvaccinated man aged 29 years with acute flaccid paralysis (AFP) associated with anterior myelitis (i.e., evidence of inflammation of the spinal cord involving the grey matter including anterior horn cell bodies) and no history of international travel during the month before symptom onset. Within 2 weeks, CDPH had received reports of two additional cases of AFP with anterior myelitis of unknown etiology. Testing at CDPH's Viral and Rickettsial Disease Laboratory for stool, nasopharyngeal swab, and cerebrospinal fluid (CSF) did not detect the presence of an enterovirus (EV), the genus of the family Picornaviridae that includes poliovirus. Additional laboratory testing for infectious diseases conducted at the CDPH Viral and Rickettsial Disease Laboratory did not identify a causative agent to explain the observed clinical syndrome reported among the patients. To identify other cases of AFP with anterior myelitis and elucidate possible common etiologies, CDPH posted alerts in official communications for California local health departments during December 2012, July 2013, and February 2014. Reports of cases of neurologic illness received by CDPH were investigated throughout this period, and clinicians were encouraged to submit clinical samples for testing. A total of 23 cases of AFP with anterior myelitis of unknown etiology were identified. Epidemiologic and laboratory investigation did not identify poliovirus infection as a possible cause for the observed cases. No common etiology was identified to explain the reported cases, although EV-D68 was identified in upper respiratory tract specimens of two patients. EV infection, including poliovirus infection, should be considered in the differential diagnosis in cases of AFP with anterior myelitis and testing performed per CDC guidelines.

Fatal transplant-associated west nile virus encephalitis and public health investigation-california, 2010.

BACKGROUND: In December 2010, a case of West Nile virus (WNV) encephalitis occurring in a kidney recipient shortly after organ transplantation was identified. METHODS: A public health investigation was initiated to determine the likely route of transmission, detect potential WNV infections among recipients from the same organ donor, and remove any potentially infected blood products or tissues. Available serum, cerebrospinal fluid, and urine samples from the organ donor and recipients were tested for WNV infection by nucleic acid testing and serology. RESULTS: Two additional recipients from the same organ donor were identified, their clinical and exposure histories were reviewed, and samples were obtained. WNV RNA was retrospectively detected in the organ donor's serum. After transplantation, the left kidney recipient had serologic and molecular evidence of WNV infection and the right kidney recipient had prolonged but clinically inapparent WNV viremia. The liver recipient showed no clinical signs of infection but had flavivirus IgG antibodies; however, insufficient samples were available to determine the timing of infection. No remaining infectious products or tissues were identified. CONCLUSIONS: Clinicians should suspect WNV as a cause of encephalitis in organ transplant recipients and report cases to public health departments for prompt investigation of the source of infection. Increased use of molecular testing and retaining pretransplantation sera may improve the ability to detect and diagnose transplant-associated WNV infection in organ transplant recipients.

Use of intravenous peramivir for treatment of severe influenza A(H1N1)pdm09.

Oral antiviral agents to treat influenza are challenging to administer in the intensive care unit (ICU). We describe 57 critically ill patients treated with the investigational intravenous neuraminidase inhibitor drug peramivir for influenza A (H1N1)pdm09 [pH1N1]. Most received late peramivir treatment following clinical deterioration in the ICU on enterically-administered oseltamivir therapy. The median age was 40 years (range 5 months-81 years). Common clinical complications included pneumonia or acute respiratory distress syndrome requiring mechanical ventilation (54; 95%), sepsis requiring vasopressor support (34/53; 64%), acute renal failure requiring hemodialysis (19/53; 36%) and secondary bacterial infection (14; 25%). Over half (29; 51%) died. When comparing the 57 peramivir-treated cases with 1627 critically ill cases who did not receive peramivir, peramivir recipients were more likely to be diagnosed with pneumonia/acute respiratory distress syndrome (p = 0.0002) or sepsis (p = <0.0001), require mechanical ventilation (p = <0.0001) or die (p = <0.0001). The high mortality could be due to the pre-existing clinical severity of cases prior to request for peramivir, but also raises questions about peramivir safety and effectiveness in hospitalized and critically ill patients. The use of peramivir merits further study in randomized controlled trials, or by use of methods such as propensity scoring and matching, to assess clinical effectiveness and safety.

Treatment with neuraminidase inhibitors for critically ill patients with influenza A (H1N1)pdm09.

BACKGROUND: Neuraminidase inhibitor (NAI) antiviral drugs can shorten the duration of uncomplicated influenza when administered early (<48 hours after illness onset) to otherwise healthy outpatients, but the optimal timing of effective therapy for critically ill patients is not well established. METHODS: We analyzed California surveillance data to characterize the outcomes of patients in intensive care units (ICUs) treated with NAIs for influenza A(H1N1)pdm09 (pH1N1). Demographic and clinical data were abstracted from medical records, using standardized case report forms. RESULTS: From 3 April 2009 through 10 August 2010, 1950 pH1N1 cases hospitalized in ICUs were reported. Of 1859 (95%) with information available, 1676 (90%) received NAI treatment, and 183 (10%) did not. The median age was 37 years (range, 1 week-93 years), 1473 (79%) had ≥1 comorbidity, and 492 (26%) died. The median time from symptom onset to starting NAI treatment was 4 days (range, 0-52 days). NAI treatment was associated with survival: 107 of 183 untreated case patients (58%) survived, compared with 1260 of 1676 treated case patients (75%; P ≤ .0001). There was a trend toward improved survival for those treated earliest (P < .0001). Treatment initiated within 5 days after symptom onset was associated with improved survival compared to those never treated (P < .05). CONCLUSIONS: NAI treatment of critically ill pH1N1 patients improves survival. While earlier treatment conveyed the most benefit, patients who started treatment up to 5 days after symptom onset also were more likely to survive. Further research is needed about whether starting NAI treatment >5 days after symptom onset may also convey benefit.

Infants hospitalized in intensive care units with 2009 H1N1 influenza infection, California, 2009-2010.

BACKGROUND: The 2009 H1N1 influenza virus emerged in April 2009 and primarily affected children and young adults. Few reports describe 2009 H1N1 influenza infection in infants. This report describes the clinical and epidemiologic features of 2009 H1N1 influenza in critically ill infants younger than 1 year of age. METHODS: Laboratory-confirmed cases were reported to the California Department of Public Health as part of public health surveillance for 2009 H1N1 influenza. Data were collected using standardized report forms and medical-chart abstractions. RESULTS: From April 23, 2009 through May 1, 2010, 82 cases of infants hospitalized in the intensive care unit with 2009 H1N1 influenza were reported in California. Medical charts were available for 77 of the infants, whose median age was 109 days (range: 1-361 days). Twenty-seven (35%) infants had a gestational age of 36 weeks or less. More than half (46; 60%) of the infants had at least 1 reported chronic medical condition. Thirty-five (45%) infants required mechanical ventilation; 7 (9%) died. Five infants were hospitalized since birth and acquired influenza infection during their admission; 2 (40%) of these infants died. CONCLUSIONS: Infants who are premature or with chronic conditions seem to be at increased risk for developing severe 2009 H1N1 influenza infection. We encourage clinicians to maintain high suspicion for influenza in infants when influenza viruses are circulating. Vaccination should be encouraged among contacts of infants <6 months of age, who are too young to be immunized or treated with licensed antivirals. Infection control measures should also be implemented in hospital settings to reduce nosocomial transmission.