Return to Travel in the Coronavirus Disease 2019 Pandemic Recovery Period and Implications for Imported Malaria: Reinforcing Prevention, Early Diagnosis, and Appropriate Treatment of Malaria.

Return to international travel in the COVID-19 pandemic recovery period is expected to increase the number of patients with imported malaria in the United States (US). Malaria prevention in travelers and preparedness for timely diagnosis and appropriate treatment are key to minimize imported malaria morbidity and mortality. Intravenous artesunate (IVAS) is now available from commercial distributors in the US for the treatment of severe malaria. Hospitals and pharmacists should have a plan for malaria treatment, including stocking artemether-lumefantrine for uncomplicated malaria, and stocking or planning for rapid procurement of IVAS for the treatment of severe malaria.

Post-artesunate Delayed Hemolysis in Patients With Severe Malaria in the United States-April 2019 Through July 2021.

BACKGROUND: Studies have demonstrated the safety and efficacy of intravenous artesunate (IVAS) for treatment of severe malaria in endemic and nonendemic countries. However, post-artesunate delayed hemolysis (PADH) is an increasingly recognized phenomenon after its administration. This study describes the prevalence and outcomes of PADH events among severe malaria cases treated with IVAS in the United States. METHODS: Patients diagnosed with severe malaria and treated with IVAS from April 2019 to July 2021 were included. Demographic, clinical, laboratory, therapeutic, and outcome measures were described using proportions, medians, and interquartile range. Patients reported to experience PADH were compared with those not reported to have PADH, and tests of significance were performed. RESULTS: Of 332 patients included in our analysis, 9 (2.7%) experienced PADH. The majority of infections in both groups were in non-Hispanic Black individuals. Parasite density (11.0% vs 8.0%), admission hemoglobin (11.0 g/dL vs 11.8 g/dL) were similar in the 2 groups. Total bilirubin levels at admission (4.7 mg/dL vs 2.2 mg/dL) and within 8 hours after completion of IVAS (2.6 mg/dL vs 1.2 mg/dL) were notably higher in PADH patients. Cumulative IVAS dose of >9.5 mg/kg and >3 doses of IVAS were risk factors for PADH. The majority (7 of 9) of PADH cases were diagnosed within 2 weeks after initiation of IVAS. Five patients (56%) required blood transfusions, and all recovered without sequelae. CONCLUSIONS: PADH is an uncommon and self-limiting adverse event in many cases; weekly monitoring of hemoglobin and hemolytic markers may identify cases requiring intervention in a timely manner.

Receipt of First and Second Doses of JYNNEOS Vaccine for Prevention of Monkeypox - United States, May 22-October 10, 2022.

Vaccination with JYNNEOS vaccine (Modified Vaccinia Ankara vaccine, Bavarian Nordic) to prevent monkeypox commenced shortly after confirmation of the first monkeypox case in the current outbreak in the United States on May 17, 2022 (1). To date, more than 27,000 cases have been reported across all 50 states, the District of Columbia (DC), and Puerto Rico.* JYNNEOS vaccine is licensed by the Food and Drug Administration (FDA) as a 0.5-mL 2-dose series administered subcutaneously 28 days apart to prevent smallpox and monkeypox infections (2) and has been found to provide protection against monkeypox infection during the current outbreak (3). The U.S. Department of Health and Human Services (HHS) allocated 1.1 million vials of JYNNEOS vaccine from the Strategic National Stockpile, with doses allocated to jurisdictions based on case counts and estimated size of population at risk (4). However, initial vaccine supplies were severely constrained relative to vaccine demand during the expanding outbreak. Some jurisdictions with highest incidence responded by prioritizing first dose administration during May-July (5,6). The FDA emergency use authorization (EUA) of 0.1 mL dosing for intradermal administration of JYNNEOS for persons aged ≥18 years on August 9, 2022, substantially expanded available vaccine supply† (7). The U.S. vaccination strategy focuses primarily on persons with known or presumed exposures to monkeypox (8) or those at high risk for occupational exposure (9). Data on monkeypox vaccine doses administered and reported to CDC by U.S. jurisdictions were analyzed to assess vaccine administration and completion of the 2-dose series. A total of 931,155 doses of JYNNEOS vaccine were administered and reported to the CDC by 55 U.S. jurisdictions during May 22-October 10, 2022. Among persons who received ≥1 dose, 51.4% were non-Hispanic White (White), 22.5% were Hispanic or Latino (Hispanic), and 12.6% were non-Hispanic Black or African American (Black). The percentages of vaccine recipients who were Black (5.6%) and Hispanic (15.5%) during May 22-June 25 increased to 13.3% and 22.7%, respectively, during July 31-October 10. Among 496,888 persons who received a first dose and were eligible for a second dose during the study period, 57.6% received their second dose. Second dose receipt was highest among older adults, White persons, and those residing in the South U.S. Census Bureau Region. Tracking and addressing disparities in vaccination can reduce inequities, and equitable access to and acceptance of vaccine should be an essential factor in planning vaccination programs, events, and strategies. Receipt of both first and second doses is necessary for optimal protection against Monkeypox virus infection.

Malaria Surveillance - United States, 2018.

PROBLEM/CONDITION: Malaria in humans is caused by intraerythrocytic protozoa of the genus Plasmodium. These parasites are transmitted by the bite of an infective female Anopheles species mosquito. Most malaria infections in the United States and its territories occur among persons who have traveled to regions with ongoing malaria transmission. However, among persons who have not traveled out of the country, malaria is occasionally acquired through exposure to infected blood or tissues, congenital transmission, nosocomial exposure, or local mosquitoborne transmission. Malaria surveillance in the United States and its territories provides information on its occurrence (e.g., temporal, geographic, and demographic), guides prevention and treatment recommendations for travelers and patients, and facilitates rapid transmission control measures if locally acquired cases are identified. PERIOD COVERED: This report summarizes confirmed malaria cases in persons with onset of illness in 2018 and trends in previous years. DESCRIPTION OF SYSTEM: Malaria cases diagnosed by blood smear microscopy, polymerase chain reaction, or rapid diagnostic tests are reported to local and state health departments through electronic laboratory reports or by health care providers or laboratory staff members directly reporting to CDC or health departments. Case investigations are conducted by local and state health departments, and reports are transmitted to CDC through the National Malaria Surveillance System (NMSS), the National Notifiable Diseases Surveillance System (NNDSS), or direct CDC clinical consultations. CDC reference laboratories provide diagnostic assistance and conduct antimalarial drug resistance marker testing on blood specimens submitted by health care providers or local or state health departments. This report summarizes data from the integration of all cases from NMSS and NNDSS, CDC clinical consultations, and CDC reference laboratory reports. RESULTS: CDC received reports of 1,823 confirmed malaria cases with onset of symptoms in 2018, including one cryptic case and one case acquired through a bone marrow transplant. The number of cases reported in 2018 is 15.6% fewer than in 2017. The number of cases diagnosed in the United States and its territories has been increasing since the mid-1970s; the number of cases reported in 2017 was the highest since 1972. Of the cases in 2018, a total of 1,519 (85.0%) were imported cases that originated from Africa; 1,061 (69.9%) of the cases from Africa were from West Africa, a similar proportion to what was observed in 2017. Among all cases, P. falciparum accounted for most infections (1,273 [69.8%]), followed by P. vivax (173 [9.5%]), P. ovale (95 [5.2%]), and P. malariae (48 [2.6%]). For the first time since 2008, an imported case of P. knowlesi was identified in the United States and its territories. Infections by two or more species accounted for 17 cases (<1.0%). The infecting species was not reported or was undetermined in 216 cases (11.9%). Most patients (92.6%) had symptom onset <90 days after returning to the United States or its territories from a country with malaria transmission. Of the U.S. civilian patients who reported reason for travel, 77.0% were visiting friends and relatives. Chemoprophylaxis with antimalarial medications are recommended for U.S. residents to prevent malaria while traveling in countries where it is endemic. Fewer U.S. residents with imported malaria reported taking any malaria chemoprophylaxis in 2018 (24.5%) than in 2017 (28.4%), and adherence was poor among those who took chemoprophylaxis. Among the 864 U.S. residents with malaria for whom information on chemoprophylaxis use and travel region were known, 95.0% did not adhere to or did not take a CDC-recommended chemoprophylaxis regimen. Among 683 women with malaria, 19 reported being pregnant. Of these, 11 pregnant women were U.S. residents, and one of whom reported taking chemoprophylaxis to prevent malaria but her adherence to chemoprophylaxis was not reported. Thirty-eight (2.1%) malaria cases occurred among U.S. military personnel in 2018, more than in 2017 (26 [1.2%]). Among all reported malaria cases in 2018, a total of 251 (13.8%) were classified as severe malaria illness, and seven persons died from malaria. In 2018, CDC analyzed 106 P. falciparum-positive and four P. falciparum mixed species specimens for antimalarial resistance markers (although certain loci were untestable in some specimens); identification of genetic polymorphisms associated with resistance to pyrimethamine were found in 99 (98.0%), to sulfadoxine in 49 (49.6%), to chloroquine in 50 (45.5%), and to mefloquine in two (2.0%); no specimens tested contained a marker for atovaquone or artemisinin resistance. INTERPRETATION: The importation of malaria reflects the overall trends in global travel to and from areas where malaria is endemic, and 15.6% fewer cases were imported in 2018 compared with 2017. Of imported cases, 59.3% were among persons who had traveled from West Africa. Among U.S. civilians, visiting friends and relatives was the most common reason for travel (77.1%). PUBLIC HEALTH ACTIONS: The best way for U.S. residents to prevent malaria is to take chemoprophylaxis medication before, during, and after travel to a country where malaria is endemic. Adherence to recommended malaria prevention strategies among U.S. travelers would reduce the number of imported cases. Reported reasons for nonadherence include prematurely stopping after leaving the area where malaria was endemic, forgetting to take the medication, and experiencing a side effect. Health care providers can make travelers aware of the risks posed by malaria and incorporate education to motivate them to be adherent to chemoprophylaxis. Malaria infections can be fatal if not diagnosed and treated promptly with antimalarial medications appropriate for the patient's age, pregnancy status, medical history, the likely country of malaria acquisition, and previous use of antimalarial chemoprophylaxis. Antimalarial use for chemoprophylaxis and treatment should be determined by the CDC guidelines, which are frequently updated. In April 2019, intravenous (IV) artesunate became the first-line medication for treatment of severe malaria in the United States and its territories. Artesunate was approved by the Food and Drug Administration (FDA) in 2020 and is commercially available (Artesunate for Injection) from major U.S. drug distributors (https://amivas.com). Stocking IV artesunate locally allows for immediate treatment of severe malaria once diagnosed and provides patients with the best chance of a complete recovery and no sequelae. With commercial IV artesunate now available, CDC will discontinue distribution of non-FDA-approved IV artesunate under an investigational new drug protocol on September 30, 2022. Detailed recommendations for preventing malaria are online at https://www.cdc.gov/malaria/travelers/drugs.html. Malaria diagnosis and treatment recommendations are also available online at https://www.cdc.gov/malaria/diagnosis_treatment. Health care providers who have sought urgent infectious disease consultation and require additional assistance on diagnosis and treatment of malaria can call the Malaria Hotline 9:00 a.m.-5:00 p.m. Eastern Time, Monday-Friday, at 770-488-7788 or 855-856-4713 or after hours for urgent inquiries at 770-488-7100. Persons submitting malaria case reports (care providers, laboratories, and state and local public health officials) should provide complete information because incomplete reporting compromises case investigations and public health efforts to prevent future infections and examine trends in malaria cases. Molecular surveillance of antimalarial drug resistance markers enables CDC to track, guide treatment, and manage drug resistance in malaria parasites both domestically and globally. A greater proportion of specimens from domestic malaria cases are needed to improve the completeness of antimalarial drug resistance analysis; therefore, CDC requests that blood specimens be submitted for any case of malaria diagnosed in the United States and its territories.

Real-Time CDC Consultation during the COVID-19 Pandemic-United States, March-July, 2020.

CONTEXT: In response to the COVID-19 pandemic, the Centers for Disease Prevention and Control (CDC) clinicians provided real-time telephone consultation to healthcare providers, public health practitioners, and health department personnel. OBJECTIVE: To describe the demographic and public health characteristics of inquiries, trends, and correlation of inquiries with national COVID-19 case reports. We summarize the results of real-time CDC clinician consultation service provided during 11 March to 31 July 2020 to understand the impact and utility of this service by CDC for the COVID-19 pandemic emergency response and for future outbreak responses. DESIGN: Clinicians documented inquiries received including information about the call source, population for which guidance was sought, and a detailed description of the inquiry and resolution. Descriptive analyses were conducted, with a focus on characteristics of callers as well as public health and clinical content of inquiries. SETTING: Real-time telephone consultations with CDC Clinicians in Atlanta, GA. PARTICIPANTS: Health care providers and public health professionals who called CDC with COVID-19 related inquiries from throughout the United States. MAIN OUTCOME MEASURES: Characteristics of inquiries including topic of inquiry, inquiry population, resolution, and demographic information. RESULTS: A total of 3154 COVID-19 related telephone inquiries were answered in real-time. More than half (62.0%) of inquiries came from frontline healthcare providers and clinical sites, followed by 14.1% from state and local health departments. The majority of inquiries focused on issues involving healthcare workers (27.7%) and interpretation or application of CDC's COVID-19 guidance (44%). CONCLUSION: The COVID-19 pandemic resulted in a substantial number of inquiries to CDC, with the large majority originating from the frontline clinical and public health workforce. Analysis of inquiries suggests that the ongoing focus on refining COVID-19 guidance documents is warranted, which facilitates bidirectional feedback between the public, medical professionals, and public health authorities.

Safety and Effectiveness of Intravenous Artesunate for Treatment of Severe Malaria in the United States-April 2019 Through December 2020.

BACKGROUND: Severe malaria can be deadly and requires treatment with intravenous artesunate (IVAS). The Centers for Disease Control and Prevention provided IVAS starting 1 April 2019 for all patients with severe malaria in the United States. This study describes the safety and effectiveness of IVAS in these patients. METHODS: Patients meeting criteria for severe malaria April 2019-December 2020 who received IVAS were included. Demographic, clinical, laboratory, adverse event, and outcome information were collected. Clinical presentation, time to reach 1% and 0% parasitemia, adverse events, and death were described using proportions, medians, interquartile range (IQR), and tests of significance for differences in proportions. RESULTS: Of 280 patients included, the majority were male (61.4%), Black (75.0%), with a median age of 35 years (IQR: 15.8-53.9). Most had Plasmodium falciparum (83.6%) with median parasitemia of 8.0% (IQR: 4.6-13.2). Of 170 patients with information, 159 (93.5%) reached ≤1% parasitemia by the third IVAS dose with a median time of 17.6 hours (IQR: 10.8-28.8), and 0% parasitemia in a median of 37.2 hours (IQR 27.2-55.2). Patients with parasite densities >10% and those requiring adjunct therapy had significantly higher parasite clearance times. Adverse events associated with IVAS were reported in 4.8% (n = 13 of 271). Eight patients had post-artesunate delayed hemolysis that resolved. There were 5 (1.8%) deaths, all attributable to severe malaria. CONCLUSIONS: IVAS is a safe and effective drug for the treatment of severe malaria in the United States; timely administration can be lifesaving.

Malaria Surveillance - United States, 2017.

PROBLEM/CONDITION: Malaria in humans is caused by intraerythrocytic protozoa of the genus Plasmodium. These parasites are transmitted by the bite of an infective female Anopheles species mosquito. The majority of malaria infections in the United States occur among persons who have traveled to regions with ongoing malaria transmission. However, malaria is occasionally acquired by persons who have not traveled out of the country through exposure to infected blood products, congenital transmission, nosocomial exposure, or local mosquitoborne transmission. Malaria surveillance in the United States is conducted to provide information on its occurrence (e.g., temporal, geographic, and demographic), guide prevention and treatment recommendations for travelers and patients, and facilitate rapid transmission control measures if locally acquired cases are identified. PERIOD COVERED: This report summarizes confirmed malaria cases in persons with onset of illness in 2017 and trends in previous years. DESCRIPTION OF SYSTEM: Malaria cases diagnosed by blood film microscopy, polymerase chain reaction, or rapid diagnostic tests are reported to local and state health departments through electronic laboratory reports or by health care providers or laboratory staff members. Case investigations are conducted by local and state health departments, and reports are transmitted to CDC through the National Malaria Surveillance System (NMSS), the National Notifiable Diseases Surveillance System (NNDSS), or direct CDC consultations. CDC reference laboratories provide diagnostic assistance and conduct antimalarial drug resistance marker testing on blood samples submitted by health care providers or local or state health departments. This report summarizes data from the integration of all cases from NMSS and NNDSS, CDC reference laboratory reports, and CDC clinical consultations. RESULTS: CDC received reports of 2,161 confirmed malaria cases with onset of symptoms in 2017, including two congenital cases, three cryptic cases, and two cases acquired through blood transfusion. The number of malaria cases diagnosed in the United States has been increasing since the mid-1970s; in 2017, the number of cases reported was the highest in 45 years, surpassing the previous peak of 2,078 confirmed cases reported in 2016. Of the cases in 2017, a total of 1,819 (86.1%) were imported cases that originated from Africa; 1,216 (66.9%) of these came from West Africa. The overall proportion of imported cases originating from West Africa was greater in 2017 (57.6%) than in 2016 (51.6%). Among all cases, P. falciparum accounted for the majority of infections (1,523 [70.5%]), followed by P. vivax (216 [10.0%]), P. ovale (119 [5.5%]), and P. malariae (55 [2.6%]). Infections by two or more species accounted for 22 cases (1.0%). The infecting species was not reported or was undetermined in 226 cases (10.5%). CDC provided diagnostic assistance for 9.5% of confirmed cases and tested 8.0% of specimens with P. falciparum infections for antimalarial resistance markers. Most patients (94.8%) had symptom onset <90 days after returning to the United States from a country with malaria transmission. Of the U.S. civilian patients who reported reason for travel, 73.1% were visiting friends and relatives. The proportion of U.S. residents with malaria who reported taking any chemoprophylaxis in 2017 (28.4%) was similar to that in 2016 (26.4%), and adherence was poor among those who took chemoprophylaxis. Among the 996 U.S. residents with malaria for whom information on chemoprophylaxis use and travel region were known, 93.3% did not adhere to or did not take a CDC-recommended chemoprophylaxis regimen. Among 805 women with malaria, 27 reported being pregnant. Of these, 10 pregnant women were U.S. residents, and none reported taking chemoprophylaxis to prevent malaria. A total of 26 (1.2%) malaria cases occurred among U.S. military personnel in 2017, fewer than in 2016 (41 [2.0%]). Among all reported cases in 2017, a total of 312 (14.4%) were classified as severe malaria illnesses, and seven persons died. In 2017, CDC analyzed 117 P. falciparum-positive and six P. falciparum mixed-species samples for antimalarial resistance markers (although certain loci were untestable in some samples); identification of genetic polymorphisms associated with resistance to pyrimethamine were found in 108 (97.3%), to sulfadoxine in 77 (69.4%), to chloroquine in 38 (33.3%), to mefloquine in three (2.7%), and to atovaquone in three (2.7%); no specimens tested contained a marker for artemisinin resistance. The data completeness of key variables (species, country of acquisition, and resident status) was lower in 2017 (74.4%) than in 2016 (79.4%). INTERPRETATION: The number of reported malaria cases in 2017 continued a decades-long increasing trend, and for the second year in a row the highest number of cases since 1971 have been reported. Despite progress in malaria control in recent years, the disease remains endemic in many areas globally. The importation of malaria reflects the overall increase in global travel to and from these areas. Fifty-six percent of all cases were among persons who had traveled from West Africa, and among U.S. civilians, visiting friends and relatives was the most common reason for travel (73.1%). Frequent international travel combined with the inadequate use of prevention measures by travelers resulted in the highest number of imported malaria cases detected in the United States in 4 decades. PUBLIC HEALTH ACTIONS: The best way to prevent malaria is to take chemoprophylaxis medication during travel to a country where malaria is endemic. Adherence to recommended malaria prevention strategies among U.S. travelers would reduce the numbers of imported cases; reasons for nonadherence include prematurely stopping after leaving the area where malaria was endemic, forgetting to take the medication, and experiencing a side effect. Travelers might not understand the risk that malaria poses to them; thus, health care providers should incorporate risk education to motivate travelers to be adherent to chemoprophylaxis. Malaria infections can be fatal if not diagnosed and treated promptly with antimalarial medications appropriate for the patient's age, medical history, the likely country of malaria acquisition, and previous use of antimalarial chemoprophylaxis. Antimalarial use for chemoprophylaxis and treatment should be informed by the most recent guidelines, which are frequently updated. In 2018, two formulations of tafenoquine (i.e., Arakoda and Krintafel) were approved by the Food and Drug Administration (FDA) for use in the United States. Arakoda was approved for use by adults for chemoprophylaxis; the regimen requires a predeparture loading dose, taking the medication weekly during travel, and a short course posttravel. The Arakoda chemoprophylaxis regimen is shorter than alternative regimens, which could possibly improve adherence. This medication also might prevent relapses. Krintafel was approved for radical cure of P. vivax infections in those aged >16 years and should be co-administered with chloroquine (https://www.cdc.gov/malaria/new_info/2020/tafenoquine_2020.html). In April 2019, intravenous artesunate became the first-line medication for treatment of severe malaria in the United States. Artesunate was recently FDA approved but is not yet commercially available. The drug can be obtained from CDC under an investigational new drug protocol. Detailed recommendations for preventing malaria are available to the general public at the CDC website (https://www.cdc.gov/malaria/travelers/drugs.html). Health care providers should consult the CDC Guidelines for Treatment of Malaria in the United States and contact the CDC's Malaria Hotline for case management advice when needed. Malaria treatment recommendations are available online (https://www.cdc.gov/malaria/diagnosis_treatment) and from the Malaria Hotline (770-488-7788 or toll-free 855-856-4713). Persons submitting malaria case reports (care providers, laboratories, and state and local public health officials) should provide complete information because incomplete reporting compromises case investigations and efforts to prevent infections and examine trends in malaria cases. Molecular surveillance of antimalarial drug resistance markers (https://www.cdc.gov/malaria/features/ars.html) enables CDC to track, guide treatment, and manage drug resistance in malaria parasites both domestically and internationally. More samples are needed to improve the completeness of antimalarial drug resistance analysis; therefore, CDC requests that blood specimens be submitted for any case of malaria diagnosed in the United States.

Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity.

BACKGROUND: Long-lasting insecticidal nets (LLINs) are the primary malaria prevention and control intervention in many parts of sub-Saharan Africa. While LLINs are expected to last at least 3 years under normal use conditions, they can lose effectiveness because they fall out of use, are discarded, repurposed, physically damaged, or lose insecticidal activity. The contributions of these different interrelated factors to durability of nets and their protection against malaria have been unclear. METHODS: Starting in 2009, LLIN durability studies were conducted in seven countries in Africa over 5 years. WHO-recommended measures of attrition, LLIN use, insecticidal activity, and physical integrity were recorded for eight different net brands. These data were combined with analyses of experimental hut data on feeding inhibition and killing effects of LLINs on both susceptible and pyrethroid resistant malaria vectors to estimate the protection against malaria transmission-in terms of vectorial capacity (VC)-provided by each net cohort over time. Impact on VC was then compared in hypothetical scenarios where one durability outcome measure was set at the best possible level while keeping the others at the observed levels. RESULTS: There was more variability in decay of protection over time by country than by net brand for three measures of durability (ratios of variance components 4.6, 4.4, and 1.8 times for LLIN survival, use, and integrity, respectively). In some countries, LLIN attrition was slow, but use declined rapidly. Non-use of LLINs generally had more effect on LLIN impact on VC than did attrition, hole formation, or insecticide loss. CONCLUSIONS: There is much more variation in LLIN durability among countries than among net brands. Low levels of use may have a larger impact on effectiveness than does variation in attrition or LLIN degradation. The estimated entomological effects of chemical decay are relatively small, with physical decay probably more important as a driver of attrition and non-use than as a direct cause of loss of effect. Efforts to maximize LLIN impact in operational settings should focus on increasing LLIN usage, including through improvements in LLIN physical integrity. Further research is needed to understand household decisions related to LLIN use, including the influence of net durability and the presence of other nets in the household.

Malaria in the pregnant traveler.

Pregnant travelers face numerous risks, notably increased susceptibility to or severity of multiple infections, including malaria. Because pregnant women residing in areas non-endemic for malaria are unlikely to have protective immunity, travel to endemic areas poses risk of severe illness and pregnancy complications, such as low birthweight and fetal loss. If travel to malaria-endemic areas cannot be avoided, preventive measures are critical. However, malaria chemoprophylaxis in pregnancy can be challenging, since commonly used regimens have varying levels of safety data and national guidelines differ. Furthermore, although chloroquine and mefloquine have wide acceptance for use in pregnancy, regional malaria resistance and non-pregnancy contraindications limit their use. Mosquito repellents, including N,N-diethyl-m-toluamide (DEET) and permethrin treatment of clothing, are considered safe in pregnancy and important to prevent malaria as well as other arthropod-borne infections such as Zika virus infection. Pregnant travelers at risk for malaria exposure should be advised to seek medical attention immediately if any symptoms of illness, particularly fever, develop.