Background: Malaria is a mosquito borne disease caused by parasites of the genus Plasmodium. In 2023, the United States (US) experienced nine cases of autochthonous Plasmodium vivax malaria transmission; seven in Florida, one in Texas, and another in Arkansas. These were the first autochthonous cases since 2003 when a cluster was identified in Florida. The aim of this study was to genetically characterize the implicated P. vivax isolates in order to complement epidemiologic investigations of these cases. Methods: A custom Illumina AmpliSeq sequencing panel capturing 495 amplicons was designed. This panel was used to ascertain whether these 2023 cases were related, and assess if they were associated with a single or separate introduction events. Sequence data were hierarchically clustered and a Naïve Bayes classification approach was used to assign genotypes to a probable geographic origin based on 113 ‘geo-informative’ SNPs captured by the panel. Genotypes associated with the 2023 Arkansas, Texas, and Florida cases were clustered alongside those sequenced from archived blood samples from the 2003 Florida case-patients, a set of reference strains, and other travel-associated specimens. Microsatellite analysis was performed on a subset of samples from these autochthonous cases to complement the AmpliSeq analysis. Findings: The 2023 autochthonous Florida cases were genetically linked as were the 2003 Florida cases. The 2023 and 2003 Florida clusters were genetically distinct, and the two Florida clusters were distinct from the 2023 Texas and Arkansas cases, which were also distinct from each other. These genotypes classified to the Central or South American region using the Naïve Bayes classifier, including those from the 2003 cluster. Interpretation: These data support that at least three distinct P. vivax introduction events in the US in 2023, involving parasites possessing genetic signatures consistent with Central or South America. Funding: This work was supported by the National Center for Emerging and Zoonotic Infectious Diseases at the US Centers for Disease Control and Prevention. © 2025

Travel-related malaria is regularly encountered in the United States, and the U.S. Centers for Disease Control and Prevention (CDC) characterizes Plasmodium falciparum drug-resistance genotypes routinely for travel-related cases. An important aspect of antimalarial drug resistance is understanding its geographic distribution. However, specimens submitted to CDC laboratories may have missing, incomplete, or inaccurate travel data. To complement genotyping for drug-resistance markers Pfcrt, Pfmdr1, Pfk13, Pfdhps, Pfdhfr, and PfcytB at CDC, amplicons of Pfs47 and Pfcpmp are also sequenced as markers of geographic origin. Here, a bi-allele likelihood (BALK) classifier was trained using Pfs47 and Pfcpmp sequences from published P. falciparum genomes of known geographic origin to classify clinical genotypes to a continent. Among P. falciparum-positive blood samples received at CDC for drug-resistance genotyping from 2018 to 2021 (n = 380), 240 included a travel history with the submission materials, though 6 were excluded due to low sequence quality. Classifications obtained for the remaining 234 were compared to their travel histories. Classification results were over 96% congruent with reported travel for clinical samples, and with collection sites for field isolates. Among travel-related samples, only two incongruent results occurred; a specimen submitted citing Costa Rican travel classified to Africa, and a specimen with travel referencing Sierra Leone classified to Asia. Subsequently, the classifier was applied to specimens with unreported travel histories (n = 140; 5 were excluded due to low sequence quality). For the remaining 135 samples, geographic classification data were paired with results generated using CDC's Malaria Resistance Surveillance (MaRS) protocol, which detects single-nucleotide polymorphisms in and generates haplotypes for Pfcrt, Pfmdr1, Pfk13, Pfdhps, Pfdhfr, and PfcytB. Given the importance of understanding the geographic distribution of antimalarial drug resistance, this work will complement domestic surveillance efforts by expanding knowledge on the geographic origin of drug-resistant P. falciparum entering the USA.

We report a fatal case of Lassa fever diagnosed in the United States in a Liberian traveler. We describe infection control protocols and public health response. One contact at high risk became symptomatic, but her samples tested negative for Lassa virus; no secondary cases occurred among health care, family, and community contacts.

Haiti, a Caribbean country of 10.5 million people, is estimated to have the highest burden of canine-mediated human rabies deaths in the Western Hemisphere, and one of the highest rates of human rabies deaths in the world. Haiti is also the poorest country in the Western Hemisphere and has numerous economic and health priorities that compete for rabies-control resources. As a result, primary rabies-control actions, including canine vaccination programs, surveillance systems for human and animal rabies, and appropriate postbite treatment, have not been fully implemented at a national scale. After the 2010 earthquake that further hindered the development of public health program infrastructure and services, the U.S. Centers for Disease Control and Prevention worked with the Ministry of Public Health and Population and key health development partners (including the Pan-American Health Organization) to provide technical expertise and funding for general disease surveillance systems, laboratory capacity, and selected disease control programs; including rabies. In 2011, a cross-ministerial rabies consortium was convened with participation from multiple international rabies experts to develop a strategy for successful rabies control in Haiti. The consortium focused on seven pillars: 1) enhancement of laboratory diagnostic capacity, 2) development of comprehensive animal surveillance system, 3) development of comprehensive human rabies surveillance system, 4) educational outreach, 5) sustainable human rabies biologics supply, 6) achievement of sustained canine vaccination rates of ≥ 70%, and 7) finalization of a national rabies control strategy. From 2010 until 2015, Haiti has seen improvements in the program infrastructure for canine rabies control. The greatest improvements were seen in the area of animal rabies surveillance, in support of which an internationally recognized rabies laboratory was developed thereby leading to an 18-fold increase in the detection of rabid animals. Canine rabies vaccination practices also improved, from a 2010 level of approximately 12% to a 2015 dog population coverage level estimated to be 45%. Rabies vaccine coverage is still below the goal of 70%, however, the positive trend is encouraging. Gaps exist in the capacity to conduct national surveillance for human rabies cases and access to human rabies vaccine is lacking in many parts of the country. However, control has improved over the past 5 years as a result of the efforts of Haiti's health and agriculture sectors with assistance from multiple international organizations. Haiti is well situated to eliminate canine-mediated human rabies deaths in the near future and should serve as a great example to many developing countries struggling with similar barriers and limitations.

Consumption of drinking water from private vendors has increased considerably in Port-au-Prince, Haiti, in recent decades. A major type of vendor is private kiosks, advertising reverse osmosis-treated water for sale by volume. To describe the scale and geographical distribution of private kiosks in metropolitan Port-au-Prince, an inventory of private kiosks was conducted from July to August 2013. Coordinates of kiosks were recorded with global positioning system units and a brief questionnaire was administered with the operator to document key kiosk characteristics. To assess the quality of water originating from private kiosks, water quality analyses were also conducted on a sample of those inventoried as well as from the major provider company sites. The parameters tested were Escherichia coli, free chlorine residual, pH, turbidity, and total dissolved solids. More than 1,300 kiosks were inventoried, the majority of which were franchises of four large provider companies. Approximately half of kiosks reported opening within 12 months of the date of the inventory. The kiosk treatment chain and sales price was consistent among a majority of the kiosks. Of the 757 kiosks sampled for water quality, 90.9% of samples met World Health Organization (WHO) microbiological guideline at the point of sale for nondetectable E. coli in a 100-mL sample. Of the eight provider company sites tested, all samples met the WHO microbiological guideline. Because of the increasing role of the private sector in drinking water provision in Port-au-Prince and elsewhere in Haiti, this assessment was an important first step for government regulation of this sector.

The American region has pledged to eliminate dog-mediated human rabies by 2015. As part of these efforts, we describe the findings of a desk and field mission review of Haiti's rabies situation by the end of 2013. While government officials recognize the importance of dog-mediated rabies control, and the national rabies plan adequately contemplates the basic capacities to that effect, regular and sufficient implementation, for example, of dog vaccination, is hampered by limited funding. Compounding insufficient funding and human resources, official surveillance figures do not accurately reflect the risk to the population, as evidenced by the large number of rabid dogs detected by focalized and enhanced surveillance activities conducted by the Ministry of Agriculture, Natural Resources and Rural Development (MARNDR) and the Health and Population Ministry (MSPP) with the technical assistance of the United States Centers for Disease Control and Prevention. Although international support is common, either in the form of on-the-ground technical support or donations of immunobiologicals, it is not comprehensive. In addition, there is limited coordination with MARNDR/MSPP and with other actors at the strategic or operational level due to human resources limitations. Given these findings, the 2015 elimination goal in the region is compromised by the situation in Haiti where control of the disease is not yet in sight despite the best efforts of the resolute national officials. More importantly, dog-mediated rabies is still a threat to the Haitian population.

OBJECTIVE: To evaluate four household water treatment (HWT) products currently seeking approval for distribution in Haiti, through the application of a recently-developed national HWT product certification process. METHODS: Four chemical treatment products were evaluated against the certification process validation stage by verifying international product certifications confirming treatment efficacy and reviewing laboratory efficacy data against WHO HWT microbiological performance targets; and against the approval stage by confirming product composition, evaluating treated water chemical content against national and international drinking water quality guidelines and reviewing packaging for dosing ability and usage directions in Creole. RESULTS: None of the four evaluated products fulfilled validation or approval stage requirements. None was certified by an international agency as efficacious for drinking water treatment, and none had data demonstrating its ability to meet WHO HWT performance targets. All product sample compositions differed from labelled composition by >20%, and no packaging included complete usage directions in Creole. CONCLUSIONS: Product manufacturers provided information that was inapplicable, did not demonstrate product efficacy, and was insufficient to ensure safe product use. Capacity building is needed with country regulatory agencies to objectively evaluate HWT products. Products should be internationally assessed against WHO performance targets and also locally approved, considering language, culture and usability, to ensure effective HWT.