Beginning in late 2023, Oropouche virus was identified as the cause of large outbreaks in Amazon regions with known endemic transmission and in new areas in South America and the Caribbean. The virus is spread to humans by infected biting midges and some mosquito species. Although infection typically causes a self-limited febrile illness, reports of two deaths in patients with Oropouche virus infection and vertical transmission associated with adverse pregnancy outcomes have raised concerns about the threat of this virus to human health. In addition to approximately 8,000 locally acquired cases in the Americas, travel-associated Oropouche virus disease cases have recently been identified in European travelers returning from Cuba and Brazil. As of August 16, 2024, a total of 21 Oropouche virus disease cases were identified among U.S. travelers returning from Cuba. Most patients initially experienced fever, myalgia, and headache, often with other symptoms including arthralgia, diarrhea, nausea or vomiting, and rash. At least three patients had recurrent symptoms after the initial illness, a common characteristic of Oropouche virus disease. Clinicians and public health jurisdictions should be aware of the occurrence of Oropouche virus disease in U.S. travelers and request testing for suspected cases. Travelers should prevent insect bites when traveling, and pregnant persons should consider deferring travel to areas experiencing outbreaks of Oropouche virus disease.

West Nile virus (WNV) is the most common domestic arbovirus in the United States. During 2018, WNV was transmitted through solid organ transplantation to 2 recipients who had neuroinvasive disease develop. Because of increased illness and death in transplant recipients, organ procurement organizations should consider screening during region-specific WNV transmission months.

BACKGROUND: Lyme disease incidence is increasing, despite current prevention options. New Lyme disease vaccine candidates are in development, however, investigation of the acceptability of a Lyme disease vaccine among potential consumers is needed prior to any vaccine coming to market. We conducted a population-based, cross-sectional study to estimate willingness to receive a potential Lyme disease vaccine and factors associated with willingness. METHODS: The web-based survey was administered to a random sample of Connecticut, Maryland, Minnesota, and New York residents June-July 2018. Survey-weighted descriptive statistics were conducted to estimate the proportion willing to receive a potential Lyme disease vaccine. Multivariable multinomial logistic regression models were used to quantify the association of sociodemographic characteristics and Lyme disease vaccine attitudes with willingness to be vaccinated. RESULTS: Surveys were completed by 3313 respondents (6% response rate). We estimated that 64% of residents were willing to receive a Lyme disease vaccine, while 30% were uncertain and 7% were unwilling. Compared to those who were willing, those who were uncertain were more likely to be parents, adults 45-65 years old, non-White, have less than a bachelor's degree, or have safety concerns about a potential Lyme disease vaccine. Those who were unwilling were also more likely to be non-White, have less than a bachelor's degree, or have safety concerns about a potential Lyme disease vaccine. In addition, the unwilling had low confidence in vaccines in general, had low perceived risk of contracting Lyme disease, and said they would not be influenced by a positive recommendation from a healthcare provider. DISCUSSION: Overall, willingness to receive a Lyme disease vaccine was high. Effective communication by clinicians regarding safety and other vaccine parameters to those groups who are uncertain will be critical for increasing vaccine uptake and reducing Lyme disease incidence.

BACKGROUND: Tick-borne encephalitis (TBE) is an arboviral disease that is focally endemic in parts of Europe and Asia. TBE cases among US travellers are rare, with previous reports of only six cases among civilian travellers through 2009 and nine military-related cases through 2020. A TBE vaccine was licenced in the USA in August 2021. Understanding TBE epidemiology and risks among US travellers can help with the counselling of travellers going to TBE-endemic areas. METHODS: Diagnostic testing for TBE in the USA is typically performed at the Centers for Disease Control and Prevention (CDC) because no commercial testing is available. Diagnostic testing for TBE at CDC since 2010 was reviewed. For individuals with evidence of TBE virus infection, information was gathered on demographics, clinical presentations and risk factors for infection. RESULTS: From 2010-20, six patients with TBE were identified. Cases occurred among both paediatric and adult travellers and all were male. Patients were diagnosed with meningitis (n = 2) or encephalitis (n = 4); none died. Cases had travelled to various countries in Europe or Russia. Three cases reported visiting friends or relatives. Activities reported included hiking, camping, trail running, or working outdoors, and two cases had a recognized tick bite. CONCLUSIONS: TBE cases among US travellers are uncommon, with these six cases being the only known TBE cases among civilian travellers during this 11-year period. Nonetheless, given potential disease severity, pre-travel counselling for travellers to TBE-endemic areas should include information on measures to reduce the risk for TBE and other tick-borne diseases, including possible TBE vaccine use if a traveller's itinerary puts them at higher risk for infection. Clinicians should consider the diagnosis of TBE in a patient with a neurologic or febrile illness recently returned from a TBE-endemic country, particularly if a tick bite or possible tick exposure is reported.

Entomological measures have long served as proxies for human risk of Lyme disease (LD) and other tickborne diseases (TBDs) in endemic areas of the United States, despite conflicting results regarding the correlation between these measures and human disease outcomes. Using data from a previous TBD intervention study in Connecticut, Maryland and New York, we evaluated whether human-tick encounters can serve as an accurate proxy for risk of TBDs in areas where LD and other Ixodes scapularis-transmitted infections are common. Among 2,590 households consisting of 4,210 individuals, experiencing a tick encounter was associated with an increased risk of both self-reported (RR = 3.17, 95% CI: 2.05, 4.91) and verified TBD (RR = 2.60, 95% CI: 1.39, 4.84) at the household level. Household characteristics associated with experiencing any tick encounter were residence in Connecticut (aOR = 1.86, 95% CI: 1.38, 2.51) or New York (aOR = 1.66, 95% CI: 1.25, 2.22), head of household having a graduate level education (aOR = 1.46, 95% CI: 1.04, 2.08), owning a pet (aOR = 1.80, 95% CI: 1.46, 2.23) and a property size of 2 acres or larger (aOR = 2.30, 95% CI: 1.42, 3.70). Results for individual characteristics were similar to those for households. Future prevention studies in LD endemic areas should consider using human-tick encounters as a robust proxy for TBD risk.

BACKGROUND: The clinical findings among children with postnatally acquired Zika virus disease are not well characterized. We describe and compare clinical signs and symptoms for children aged <18 years. METHODS: Zika virus disease cases were included if they met the national surveillance case definition, had illness onset in 2016 or 2017, resided in a participating state, and were reported to CDC. Pediatric cases were aged <18 years; congenital and perinatal infections were excluded. Pediatric cases were matched to adult cases (1849 years). Clinical information was compared between younger and older pediatric cases and between children and adults. RESULTS: A total of 141 pediatric Zika virus disease cases were identified; none experienced neurologic disease. Overall, 28 (20%) were treated in an emergency department, 1 (<1%) was hospitalized; none died. Of the four primary clinical signs and symptoms associated with Zika virus disease, 133 (94%) children had rash, 104 (74%) fever, 67 (48%) arthralgia, and 51 (36%) conjunctivitis. Fever, arthralgia, and myalgia were more common in older children (1217 years) than younger children (111 years). Arthralgia, arthritis, edema, and myalgia were more common in adults compared to children. CONCLUSIONS: This report supports previous findings that Zika virus disease is generally mild in children. The most common symptoms are similar to other childhood infections, and clinical findings and outcomes are similar to those in adults. Healthcare providers should consider a diagnosis of Zika virus infection in children with fever, rash, arthralgia, or conjunctivitis, who reside in or have traveled to an area where Zika virus transmission is occurring.

BACKGROUND: Transfusion-transmitted malaria (TTM) is a rare occurrence with serious consequences for the recipient. A case study is presented as an example of best practices for conducting a TTM investigation. CASE REPORT: A 15-year-old male with a history of sickle cell disease developed fever after a blood transfusion. He was diagnosed with Plasmodium falciparum malaria and was successfully treated. The American Red Cross, New York State Department of Health, and the Centers for Disease Control and Prevention investigated the eight donors who provided components to the transfusion. The investigation to identify a malaria-positive donor included trace back of donors, serologic methods to identify donor(s) with a history of malaria exposure, polymerase chain reaction (PCR) testing, microsatellite analysis to identify the parasite in a donor and match its genotype to the parasite in the recipient, and reinterview of all donors to clarify malaria risk factors. RESULTS: One donor had evidence of infection with P. falciparum by PCR, elevated antibody titers, and previously undisclosed malaria risk factors. Reinterview revealed that the donor immigrated to the United States from Togo just short of 3 years before the blood donation. The donor was treated for asymptomatic low parasitemia infection. CONCLUSION: This investigation used standard procedures for investigating TTM but also demonstrated the importance of applying sensitive laboratory techniques to identify the infected donor, especially a donor with asymptomatic infection with low parasitemia. Repeat interview of all donors identified as having contributed to the transfused component provides complementary epidemiologic information to confirm the infected donor.

The value of using diagnostic codes in Lyme disease (LD) surveillance in highly endemic states has not been well studied. Surveys of healthcare facilities in Maryland (MD) and New York (NY) regarding coding practices were conducted to evaluate the feasibility of using diagnostic codes as a potential method for LD surveillance. Most respondents indicated that their practice utilized electronic medical records (53%) and processed medical/billing claims electronically (74%). Most facilities were able to search office visits associated with specific ICD-9-CM and CPT codes (74% and 73%, respectively); no discernible differences existed between the healthcare facilities in both states. These codes were most commonly assigned by the practitioner (82%), and approximately 70% of respondents indicated that these codes were later validated by administrative staff. These results provide evidence for the possibility of using diagnostic codes in LD surveillance. However, the utility of these codes as an alternative to traditional LD surveillance requires further evaluation.

BACKGROUND: In collaboration with state, tribal, local, and territorial health departments, CDC established the U.S. Zika Pregnancy Registry (USZPR) in early 2016 to monitor pregnant women with laboratory evidence of possible recent Zika virus infection and their infants. METHODS: This report includes an analysis of completed pregnancies (which include live births and pregnancy losses, regardless of gestational age) in the 50 U.S. states and the District of Columbia (DC) with laboratory evidence of possible recent Zika virus infection reported to the USZPR from January 15 to December 27, 2016. Birth defects potentially associated with Zika virus infection during pregnancy include brain abnormalities and/or microcephaly, eye abnormalities, other consequences of central nervous system dysfunction, and neural tube defects and other early brain malformations. RESULTS: During the analysis period, 1,297 pregnant women in 44 states were reported to the USZPR. Zika virus-associated birth defects were reported for 51 (5%) of the 972 fetuses/infants from completed pregnancies with laboratory evidence of possible recent Zika virus infection (95% confidence interval [CI] = 4%-7%); the proportion was higher when restricted to pregnancies with laboratory-confirmed Zika virus infection (24/250 completed pregnancies [10%, 95% CI = 7%-14%]). Birth defects were reported in 15% (95% CI = 8%-26%) of fetuses/infants of completed pregnancies with confirmed Zika virus infection in the first trimester. Among 895 liveborn infants from pregnancies with possible recent Zika virus infection, postnatal neuroimaging was reported for 221 (25%), and Zika virus testing of at least one infant specimen was reported for 585 (65%). CONCLUSIONS AND IMPLICATIONS FOR PUBLIC HEALTH PRACTICE: These findings highlight why pregnant women should avoid Zika virus exposure. Because the full clinical spectrum of congenital Zika virus infection is not yet known, all infants born to women with laboratory evidence of possible recent Zika virus infection during pregnancy should receive postnatal neuroimaging and Zika virus testing in addition to a comprehensive newborn physical exam and hearing screen. Identification and follow-up care of infants born to women with laboratory evidence of possible recent Zika virus infection during pregnancy and infants with possible congenital Zika virus infection can ensure that appropriate clinical services are available.

We report on 9 cases of male-to-female sexual transmission of Zika virus in the United States occurring January-April 2016. This report summarizes new information about both timing of exposure and symptoms of sexually transmitted Zika virus disease, and results of semen testing for Zika virus from 2 male travelers.

Importance: Understanding the risk of birth defects associated with Zika virus infection during pregnancy may help guide communication, prevention, and planning efforts. In the absence of Zika virus, microcephaly occurs in approximately 7 per 10000 live births. Objective: To estimate the preliminary proportion of fetuses or infants with birth defects after maternal Zika virus infection by trimester of infection and maternal symptoms. Design, Setting, and Participants: Completed pregnancies with maternal, fetal, or infant laboratory evidence of possible recent Zika virus infection and outcomes reported in the continental United States and Hawaii from January 15 to September 22, 2016, in the US Zika Pregnancy Registry, a collaboration between the CDC and state and local health departments. Exposures: Laboratory evidence of possible recent Zika virus infection in a maternal, placental, fetal, or infant sample. Main Outcomes and Measures: Birth defects potentially Zika associated: brain abnormalities with or without microcephaly, neural tube defects and other early brain malformations, eye abnormalities, and other central nervous system consequences. Results: Among 442 completed pregnancies in women (median age, 28 years; range, 15-50 years) with laboratory evidence of possible recent Zika virus infection, birth defects potentially related to Zika virus were identified in 26 (6%; 95% CI, 4%-8%) fetuses or infants. There were 21 infants with birth defects among 395 live births and 5 fetuses with birth defects among 47 pregnancy losses. Birth defects were reported for 16 of 271 (6%; 95% CI, 4%-9%) pregnant asymptomatic women and 10 of 167 (6%; 95% CI, 3%-11%) symptomatic pregnant women. Of the 26 affected fetuses or infants, 4 had microcephaly and no reported neuroimaging, 14 had microcephaly and brain abnormalities, and 4 had brain abnormalities without microcephaly; reported brain abnormalities included intracranial calcifications, corpus callosum abnormalities, abnormal cortical formation, cerebral atrophy, ventriculomegaly, hydrocephaly, and cerebellar abnormalities. Infants with microcephaly (18/442) represent 4% of completed pregnancies. Birth defects were reported in 9 of 85 (11%; 95% CI, 6%-19%) completed pregnancies with maternal symptoms or exposure exclusively in the first trimester (or first trimester and periconceptional period), with no reports of birth defects among fetuses or infants with prenatal exposure to Zika virus infection only in the second or third trimesters. Conclusions and Relevance: Among pregnant women in the United States with completed pregnancies and laboratory evidence of possible recent Zika infection, 6% of fetuses or infants had evidence of Zika-associated birth defects, primarily brain abnormalities and microcephaly, whereas among women with first-trimester Zika infection, 11% of fetuses or infants had evidence of Zika-associated birth defects. These findings support the importance of screening pregnant women for Zika virus exposure.

OBJECTIVE: Zika virus infection during pregnancy is a cause of microcephaly and other fetal brain abnormalities. Reports indicate that the duration of detectable viral RNA in serum after symptom onset is brief. In a recent case report involving a severely affected fetus, Zika virus RNA was detected in maternal serum 10 weeks after symptom onset, longer than the duration of RNA detection in serum previously reported. This report summarizes the clinical and laboratory characteristics of pregnant women with prolonged detection of Zika virus RNA in serum that were reported to the U.S. Zika Pregnancy Registry. METHODS: Data were obtained from the U.S. Zika Pregnancy Registry, an enhanced surveillance system of pregnant women with laboratory evidence of confirmed or possible Zika virus infection. For this case series, we defined prolonged detection of Zika virus RNA as Zika virus RNA detection in serum by real-time reverse transcription-polymerase chain reaction (RT-PCR) 14 or more days after symptom onset or, for women not reporting signs or symptoms consistent with Zika virus disease (asymptomatic), 21 or more days after last possible exposure to Zika virus. RESULTS: Prolonged Zika virus RNA detection in serum was identified in four symptomatic pregnant women up to 46 days after symptom onset and in one asymptomatic pregnant woman 53 days postexposure. Among the five pregnancies, one pregnancy had evidence of fetal Zika virus infection confirmed by histopathologic examination of fetal tissue, three pregnancies resulted in live births of apparently healthy neonates with no reported abnormalities, and one pregnancy is ongoing. CONCLUSION: Zika virus RNA was detected in the serum of five pregnant women beyond the previously estimated timeframe. Additional real-time RT-PCR testing of pregnant women might provide more data about prolonged detection of Zika virus RNA and the possible diagnostic, epidemiologic, and clinical implications for pregnant women.

BACKGROUND: In the northeastern United States, tickborne diseases are a major public health concern. In controlled studies, a single springtime application of acaricide has been shown to kill between 68 and 100% of ticks. Although public health authorities recommend use of acaricides to control tick populations in yards, the effectiveness of these pesticides to prevent tick bites or human tickborne diseases is unknown. METHODS: We conducted a 2-year, randomized, double-blinded, placebo-controlled trial among 2,727 households in three Northeastern states. Households received a single springtime barrier application of bifenthrin or water according to recommended practices. Tick drags were conducted 3-4 weeks post-treatment on 10% of properties. Information on human-tick encounters and tickborne diseases was collected through monthly surveys; reports of illness were validated by medical record review. RESULTS: Although abundance of questing ticks was significantly lower (63%) on acaricide-treated properties, there was no difference between treatment groups in human-tick encounters, self-reported or medical record-validated tickborne diseases. CONCLUSIONS: Used as recommended, acaricide barrier sprays do not significantly reduce household risk of tick exposure or tickborne disease. Measures for preventing tickborne diseases should be evaluated against human outcomes to confirm effectiveness.

Large commercial laboratories in the United States were surveyed regarding the number of specimens tested for eight tickborne diseases in 2008. Seven large commercial laboratories reported testing a total of 2,927,881 specimens nationally (including Lyme disease). Of these, 495,585 specimens (17%) were tested for tickborne diseases other than Lyme disease. In addition to large commercial laboratories, another 1051 smaller commercial, hospital, and government laboratories in four states (CT, MD, MN, and NY) were surveyed regarding tickborne disease testing frequency, practices, and results. Ninety-two of these reported testing a total of 10,091 specimens for four tickborne diseases other than Lyme disease. We estimate the cost of laboratory diagnostic testing for non-Lyme disease tickborne diseases in 2008 to be $9.6 million. These data provide a baseline to evaluate trends in tickborne disease test utilization and insight into the burden of these diseases.

Ixodes scapularis, commonly known as the blacklegged tick, is responsible for transmitting Lyme disease (caused by Borrelia burgdorferi), the most common vector-borne disease in the United States (Centers for Disease Control and Prevention 2014). The blacklegged tick can also transmit Anaplasma phagocytophilum (the etiologic agent of human granulocytic anaplasmosis), Babesia microti (the causative agent of babesiosis), Borrelia miyamotoi (a relapsing fever Borrelia), and deer tick virus. In the northeastern U.S., the highest risk of exposure to the blacklegged tick is likely peridomestic, due to fragmented forest landscapes and other land-use characteristics, as well as the intrusion of humans into prime habitat for blacklegged ticks and their hosts (Falco and Fish 1988, Maupin et al. 1991, Nicholson and Mather 1996, Brownstein et al. 2005). Despite this, most reports of tick abundance and infection rates focus primarily on ticks collected from public lands and forested research sites (Aliota et al. 2014, Barbour et al. 2009, Diuk-Wasser et al. 2012, Hersh et al. 2014, Keesing et al. 2014). | We collected ticks from residential properties in Lyme disease-endemic areas and determined infection rates for nymphal I. scapularis as part of a two-year, multi-site tickborne disease intervention study involving the Centers for Disease Control and Prevention (CDC) and the Emerging Infections Programs in Connecticut (CT), Maryland (MD) and New York (NY). Here, we present tick densities and infection rates for B. burgdorferi, A. phagocytophilum, and B. microti from nymphal I. scapularis, reflecting peridomestic exposure to these pathogens.

Jamestown Canyon virus (JCV) is a mosquito-borne orthobunyavirus in the California serogroup that can cause an acute febrile illness, meningitis, or meningoencephalitis. We describe epidemiologic and clinical features for JCV disease cases occurring in the United States during 2000-2013. A case of JCV disease was defined as an acute illness in a person with laboratory evidence of a recent JCV infection. During 2000-2013, we identified 31 cases of JCV disease in residents of 13 states. The median age was 48 years (range, 10-69) and 21 (68%) were male. Eleven (35%) case patients had meningoencephalitis, 6 (19%) meningitis, 7 (23%) fever without neurologic involvement, and 7 (23%) had an unknown clinical syndrome. Fifteen (48%) were hospitalized and there were no deaths. Health-care providers and public health officials should consider JCV disease in the differential diagnoses of viral meningitis and encephalitis, obtain appropriate specimens for testing, and report cases to public health authorities.

On December 13, 2013, MMWR published a report describing three cases of sudden cardiac death associated with Lyme carditis. State public health departments and CDC conducted a follow-up investigation to determine 1) whether carditis was disproportionately common among certain demographic groups of patients diagnosed with Lyme disease, 2) the frequency of death among patients diagnosed with Lyme disease and Lyme carditis, and 3) whether any additional deaths potentially attributable to Lyme carditis could be identified. Lyme disease cases are reported to CDC through the Nationally Notifiable Disease Surveillance System; reporting of clinical features, including Lyme carditis, is optional. For surveillance purposes, Lyme carditis is defined as acute second-degree or third-degree atrioventricular conduction block accompanying a diagnosis of Lyme disease. During 2001-2010, a total of 256,373 Lyme disease case reports were submitted to CDC, of which 174,385 (68%) included clinical information. Among these, 1,876 (1.1%) were identified as cases of Lyme carditis. Median age of patients with Lyme carditis was 43 years (range = 1-99 years); 1,209 (65%) of the patients were male, which is disproportionately larger than the male proportion among patients with other clinical manifestations (p<0.001). Of cases with this information available, 69% were diagnosed during the months of June-August, and 42% patients had an accompanying erythema migrans, a characteristic rash. Relative to patients aged 55-59 years, carditis was more common among men aged 20-39 years, women aged 25-29 years, and persons aged ≥75 years.

BACKGROUND: Laboratory testing is helpful when evaluating patients with suspected Lyme disease (LD). A two-tiered antibody testing approach is recommended, but single-tier and non-validated tests are also used. We conducted a survey of large commercial laboratories in the United States to assess laboratory practices. We used these data to estimate the cost of testing and number of infections among patients from whom specimens were submitted. METHODS: Large commercial laboratories were asked to report the type and volume of testing conducted nationwide in 2008, as well as the percent of positive tests for four LD endemic states. The total direct cost of testing was calculated for each test type. These data and test-specific performance parameters available in published literature were used to estimate the number of infections among source patients. RESULTS: Seven participating laboratories performed approximately 3.4 million LD tests on approximately 2.4 million specimens nationwide at an estimated cost of $492 million. Two-tiered testing accounted for at least 62% of assays performed; alternative testing accounted for less than 3% of assays. The estimated frequency of infection among patients from whom specimens were submitted ranged from 10% to 18.5%. Applied to the total numbers of specimens, this yielded an estimated 240,000 to 444,000 infected source patients in 2008. DISCUSSION: LD testing is common and costly, with most testing in accordance with diagnostic recommendations. These results highlight the importance of considering clinical and exposure history when interpreting laboratory results for diagnostic and surveillance purposes.

Sylvatic typhus is an infrequent, potentially life-threatening emerging zoonotic disease. In January of 2009, the New York State Department of Health was notified of a familial cluster of two suspected cases. Due to the paucity of typhus cases in New York, epidemiologic and environmental investigations were conducted to establish rickettsial etiology and determine potential sources of infection. Patients presented with symptoms consistent with typhus, and serologic testing of each patient confirmed infection with typhus group rickettsiae. Serologic analysis of blood obtained from southern flying squirrels (Glaucomys volans) captured from the attic crawlspace above an enclosed front porch of the cases' residence indicated evidence of infection with Rickettsia prowazekii, with 100% seroprevalence (n=11). Both patients reported spending significant time on the porch and hearing animal activity above the ceiling prior to onset of illness, implicating these flying squirrels as the likely source of infection.