Salmonella Hadar linked to two distinct transmission vehicles highlights challenges to enteric disease outbreak investigations.

In 2020, an outbreak of Salmonella Hadar illnesses was linked to contact with non-commercial, privately owned (backyard) poultry including live chickens, turkeys, and ducks, resulting in 848 illnesses. From late 2020 to 2021, this Salmonella Hadar strain caused an outbreak that was linked to ground turkey consumption. Core genome multilocus sequence typing (cgMLST) analysis determined that the Salmonella Hadar isolates detected during the outbreak linked to backyard poultry and the outbreak linked to ground turkey were closely related genetically (within 0-16 alleles). Epidemiological and traceback investigations were unable to determine how Salmonella Hadar detected in backyard poultry and ground turkey were linked, despite this genetic relatedness. Enhanced molecular characterization methods, such as analysis of the pangenome of Salmonella isolates, might be necessary to understand the relationship between these two outbreaks. Similarly, enhanced data collection during outbreak investigations and further research could potentially aid in determining whether these transmission vehicles are truly linked by a common source and what reservoirs exist across the poultry industries that allow Salmonella Hadar to persist. Further work combining epidemiological data collection, more detailed traceback information, and genomic analysis tools will be important for monitoring and investigating future enteric disease outbreaks.

Tick-borne encephalitis among US travellers, 2010-20.

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.

Cluster of human Salmonella Guinea infections: Reported reptile exposures and associated opportunities for infection prevention - Ohio, 2019-2020.

A cluster of five human Salmonella Guinea cases was identified among Ohio residents through core genome multilocus sequence typing of clinical isolates. An investigation was conducted to characterize illnesses and identify common exposures. Four patients were aged ≤5 years and three of four patients with information available regarding exposure to animals reported prior exposure to bearded dragons. Practices that potentially increased the risk for Salmonella transmission from reptiles to humans included allowing pet reptiles to roam freely in the home, cleaning reptile habitats indoors, and kissing reptiles. These findings prompted a multistate investigation that resulted in the identification of additional closely related Salmonella Guinea isolates from patients across multiple states. The investigation of cases in Ohio and information shared by other states indicated the potential association between human Salmonella Guinea infections and reptiles, particularly bearded dragons. To prevent Salmonella transmission from reptiles, continued educational efforts should address pet owners and focus on specific reptile ownership practices.

West Nile Virus Transmission by Solid Organ Transplantation and Considerations for Organ Donor Screening Practices, United States.

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.

Investigation of Acute Flaccid Paralysis Reported with La Crosse Virus Infection, Ohio, USA, 2008-2014.

Infection with La Crosse virus can cause meningoencephalitis, but it is not known to cause acute flaccid paralysis (AFP). During 2008-2014, nine confirmed or probable La Crosse virus disease cases with possible AFP were reported in Ohio, USA. After an epidemiologic and clinical investigation, we determined no patients truly had AFP.

Notes from the field: multistate outbreak of human salmonella infections linked to live poultry from a mail-order hatchery in Ohio--February-October 2014.

In early 2014, five clusters of human Salmonella infections were identified through PulseNet, the national molecular subtyping network for foodborne disease surveillance. Many ill persons in each of these clusters reported contact with live poultry, primarily chicks and ducklings, from a single mail-order hatchery; therefore, the clusters were merged into a single investigation. During February 3-October 14, 2014, a total of 363 persons infected with outbreak strains of Salmonella serotypes Infantis, Newport, and Hadar were reported from 43 states and Puerto Rico, making it the largest live poultry-associated salmonellosis outbreak reported in the United States.

Multistate outbreak of human Salmonella infections linked to live poultry from a mail-order hatchery in Ohio--March-September 2013.

In early 2013, four clusters of human Salmonella infections were identified through PulseNet, the national molecular subtyping network for foodborne bacteria. Many of the ill persons in these four clusters reported contact with live poultry, primarily chicks and ducklings, from a single mail-order hatchery; therefore, these investigations were merged. During March 4-October 9, 2013, a total of 158 persons infected with outbreak strains of Salmonella serotypes Infantis, Lille, Newport, and Mbandaka were reported from 30 states.

Prolonged university outbreak of meningococcal disease associated with a serogroup B strain rarely seen in the United States.

BACKGROUND: College students living in residential halls are at increased risk of meningococcal disease. Unlike that for serogroups prevented by quadrivalent meningococcal vaccines, public health response to outbreaks of serogroup B meningococcal disease is limited by lack of a US licensed vaccine. METHODS: In March 2010, we investigated a prolonged outbreak of serogroup B disease associated with a university. In addition to case ascertainment, molecular typing of isolates was performed to characterize the outbreak. We conducted a matched case-control study to examine risk factors for serogroup B disease. Five controls per case, matched by college year, were randomly selected. Participants completed a risk factor questionnaire. Data were analyzed using conditional logistic regression. RESULTS: Between January 2008 and November 2010, we identified 13 meningococcal disease cases (7 confirmed, 4 probable, and 2 suspected) involving 10 university students and 3 university-linked persons. One student died. Ten cases were determined to be serogroup B. Isolates from 6 confirmed cases had an indistinguishable pulsed-field gel electrophoresis pattern and belonged to sequence type 269, clonal complex 269. Factors significantly associated with disease were Greek society membership (matched odds ratio [mOR], 15.0; P = .03), >1 kissing partner (mOR, 13.66; P = .03), and attending bars (mOR, 8.06; P = .04). CONCLUSIONS: The outbreak was associated with a novel serogroup B strain (CC269) and risk factors were indicative of increased social mixing. Control measures were appropriate but limited by lack of vaccine. Understanding serogroup B transmission in college and other settings will help inform use of serogroup B vaccines currently under consideration for licensure.