A case of locally acquired (autochthonous) mosquito-transmitted Plasmodium vivax malaria was diagnosed in Arkansas in September 2023. This represents the 10th autochthonous case identified nationally in 2023, after 20 years without recorded local mosquitoborne malaria transmission in the United States. The public health response included case investigation, active case surveillance, mosquito surveillance and control, assessment of medical countermeasures, and clinical and public outreach. Prompt diagnosis and appropriate treatment of malaria can improve clinical outcomes and, in addition to vector control, minimize risk for local transmission. Clinicians should consider malaria among patients who have traveled to countries where malaria is endemic, or with unexplained fever regardless of travel history. Although the risk for autochthonous malaria in the United States remains very low, its reemergence highlights the importance of vectorborne disease preparedness and response. Examples of such efforts include improving awareness among clinicians, access to diagnostics and antimalarial medications, and capacity for mosquito surveillance and control. Collaboration and communication among CDC, health departments, local jurisdictions, clinicians, hospitals, laboratories, and the public can support rapid malaria diagnosis, prevention, and control. Before traveling internationally to areas where malaria is endemic, travelers should consult with their health care provider regarding recommended malaria prevention measures, including chemoprophylaxis and precautions to avoid mosquito bites, to reduce both personal and community risk.

We investigated an outbreak initially attributed to norovirus; however, Clostridium perfringens toxicoinfection was subsequently confirmed. C. perfringens is an underrecognized but frequently observed cause of foodborne disease outbreaks. This investigation illustrates the importance of considering epidemiologic and laboratory data together when evaluating potential etiologies that might require unique control measures.

During December 2009, over 200 individuals reported gastrointestinal symptoms after dining at a North Carolina restaurant. An outbreak investigation included a case-control study of restaurant patrons, a secondary household transmission study, environmental assessment of the restaurant facilities and operations, and laboratory analysis of stool and food samples. Illness was primarily associated with consumption of steamed oysters (odds ratio 12, 95% confidence interval 4.8-28) and 20% (8/41 households) reported secondary cases, with a secondary attack rate of 14% among the 70 susceptible household contacts. Norovirus RNA was detected in 3/5 stool specimens from ill patrons; sequencing of RT-PCR products from two of these specimens identified identical genogroup II genotype 12 sequences. Final cooked temperatures of the steamed oysters were generally inadequate to inactivate norovirus, ranging from 21 degrees C to 74 degrees C. Undercooked contaminated oysters pose a similar risk for norovirus illness as raw oysters and household contacts are at risk for secondary infection.

Choropleth maps are commonly used in cancer reports and community discussions about cancer rates. Cancer registries increasingly use geographic information system techniques. The Centers for Disease Control and Prevention's Division of Cancer Prevention and Control convened a Map Work Group to help guide application of geographic information systems mapping techniques and to promote choropleth mapping of data from central cancer registries supported by the National Program of Cancer Registries, especially for planning and evaluation of comprehensive cancer control programs. In this 2-part series in this issue of Preventing Chronic Disease, we answer frequently asked questions about choropleth map design to display cancer incidence data. We recommend that future initiatives consider more advanced mapping, spatial analysis, and spatial statistics techniques, and include usability testing with representatives of state and local programs and other cancer prevention partners.

Choropleth maps are commonly used in cancer reports and community discussions about cancer rates. Cancer registries increasingly use geographic information system techniques. The Centers for Disease Control and Prevention's Division of Cancer Prevention and Control convened a Map Work Group to help guide application of geographic information system mapping techniques and to promote choropleth mapping of data from central cancer registries supported by the National Program of Cancer Registries, especially for comprehensive cancer control planning and evaluation purposes. In this 2-part series, we answer frequently asked questions about choropleth map design to display cancer incidence data. We recommend that future initiatives consider more advanced mapping, spatial analysis, and spatial statistics techniques and include usability testing with representatives of state and local programs and other cancer prevention partners.