Characteristics and Severity of Disease among 100 Cases of Imported Malaria Seen at a U.S. University Hospital, 2000-2017

Epidemiological and clinical characteristics of imported falciparum malaria in the Republic of North Macedonia : A 13-year experience

BACKGROUND

Plasmodium falciparum is the leading cause of imported malaria and the most common cause of death in returning travellers.

AIM

To identify the main epidemiological and clinical characteristics of patients with imported falciparum malaria in the Republic of North Macedonia.

MATERIAL AND METHODS

Retrospectively analyzed were the epidemiological and clinical features of 34 patients with imported falciparum malaria who were diagnosed and treated at the university clinic for infectious diseases and febrile conditions in Skopje from 2010 to 2022. Malaria diagnosis was based on the microscopic detection of parasites in thick and thin blood smears.

RESULTS

All patients were male, with a median age of 36 years and a range of 22-60 years. Of the patients 33 (97.1%) acquired the disease in Sub-Saharan Africa. All patients except one stayed in endemic regions for work/business purposes. Chemoprophylaxis was completely applied in 4 (11.8%) patients. The median time of onset between the symptoms and diagnosis was 4 days, with a range of 1-12 days. Prevailing clinical manifestations were fever, chills, and splenomegaly in 100%, 94%, and 68% of patients, respectively. Severe malaria was noticed in 8 (23.5%) patients. In 5 (14.7%) patients the initial parasitemia was higher than 5%. On admission, thrombocytopenia, hyperbilirubinemia, and elevated alanine aminotransferase were registered in 94%, 58%, and 62% of patients, respectively. Out of the 33 patients with adequate follow-up, the outcome was favorable in 31 (93.9%).

CONCLUSION

In every febrile traveller returned from Africa, imported falciparum malaria should be an essential part of differential diagnostic considerations.

Diagnosis, Treatment, and Prevention of Malaria in the US: A Review

IMPORTANCE

Malaria is caused by protozoa parasites of the genus Plasmodium and is diagnosed in approximately 2000 people in the US each year who have returned from visiting regions with endemic malaria. The mortality rate from malaria is approximately 0.3% in the US and 0.26% worldwide.

OBSERVATIONS

In the US, most malaria is diagnosed in people who traveled to an endemic region. More than 80% of people diagnosed with malaria in the US acquired the infection in Africa. Of the approximately 2000 people diagnosed with malaria in the US in 2017, an estimated 82.4% were adults and about 78.6% were Black or African American. Among US residents diagnosed with malaria, 71.7% had not taken malaria chemoprophylaxis during travel. In 2017 in the US, P falciparum was the species diagnosed in approximately 79% of patients, whereas P vivax was diagnosed in an estimated 11.2% of patients. In 2017 in the US, severe malaria, defined as vital organ involvement including shock, pulmonary edema, significant bleeding, seizures, impaired consciousness, and laboratory abnormalities such as kidney impairment, acidosis, anemia, or high parasitemia, occurred in approximately 14% of patients, and an estimated 0.3% of those receiving a diagnosis of malaria in the US died. P falciparum has developed resistance to chloroquine in most regions of the world, including Africa. First-line therapy for P falciparum malaria in the US is combination therapy that includes artemisinin. If P falciparum was acquired in a known chloroquine-sensitive region such as Haiti, chloroquine remains an alternative option. When artemisinin-based combination therapies are not available, atovaquone-proguanil or quinine plus clindamycin is used for chloroquine-resistant malaria. P vivax, P ovale, P malariae, and P knowlesi are typically chloroquine sensitive, and treatment with either artemisinin-based combination therapy or chloroquine for regions with chloroquine-susceptible infections for uncomplicated malaria is recommended. For severe malaria, intravenous artesunate is first-line therapy. Treatment of mild malaria due to a chloroquine-resistant parasite consists of a combination therapy that includes artemisinin or chloroquine for chloroquine-sensitive malaria. P vivax and P ovale require additional therapy with an 8-aminoquinoline to eradicate the liver stage. Several options exist for chemoprophylaxis and selection should be based on patient characteristics and preferences.

CONCLUSIONS AND RELEVANCE

Approximately 2000 cases of malaria are diagnosed each year in the US, most commonly in travelers returning from visiting endemic areas. Prevention and treatment of malaria depend on the species and the drug sensitivity of parasites from the region of acquisition. Intravenous artesunate is first-line therapy for severe malaria.

Live attenuated rubella vectors expressing Plasmodium falciparum circumsporozoite protein (Pf-CSP) provide a novel malaria vaccine platform in the rhesus macaque

There is an urgent need for a malaria vaccine that can prevent severe disease in young children and adults. Despite earlier work showing an immunological mechanism for preventing infection and reducing disease severity, there is currently no reliable vaccine that can provide durable protection. In part, this may reflect a limited number of ways that the host can respond to the NANP repeat sequences of circumsporozoite protein (CSP) in the parasite. In addition, it may reflect antigenic escape by the parasite from protective antibodies. To be successful, a vaccine must protect against repeated exposure to infected mosquitoes in endemic areas. We have created a series of live viral vectors based on the rubella vaccine strain that express multiple tandem repeats of NANP, and we demonstrate immunogenicity in a rhesus macaque model. We tested the vectors in a sequential immunization strategy. In the first step, the animals were primed with CSP-DNA vaccine and boosted with rubella/CSP vectors. In the second step, we gave rubella/CSP vectors again, followed by recombinant CSP protein. Following the second step, antibody titers were comparable to adult exposure to malaria in an endemic area. The antibodies were specific for native CSP protein on sporozoites, and they persisted for at least 1½ years in two out of three macaques. Given the safety profile of rubella vaccine in children, these vectors could be most useful in protecting young children, who are at greatest risk of severe malarial disease.

Ensuring the Safety of Yellow Fever Vaccination in Travelers-The Experience at a Large U.S. Academic Medical Center in Colorado

Background: Yellow fever (YF) virus has the potential to cause fatal outcomes among at-risk individuals visiting endemic areas. Vaccinating travelers who are at risk is necessary to prevent virus-related life-threatening complications. We lack data on the clinical features of persons seeking YF vaccination. We aim to describe the characteristics of a cohort of persons receiving the YF vaccine before travel. Methods: A retrospective analysis of 964 travelers receiving the YF vaccine (Stamaril^®) from Oct 2016 to Jul 2019 was performed at the University of Colorado Hospital, U.S. Percentages, means, and standard deviations were calculated. A multivariate logistic regression model was built to evaluate the association between receiving YF vaccination less than 10 days before departure and visiting friends and relatives (VFR). Results: The average age of the subjects was 39 ± 18 years with a range of nine months to 83 years. Persons who were 60 years of age and older represented 17%. Women consisted of 52%, and most of the travelers were Caucasians (64%). Travelers reported traveling to Africa (57%) or South America (40%). The primary destinations for travelers overall were Kenya (19%), Uganda (11%), and Tanzania (11%) in Africa; and Peru (14%) and Brazil (13%) in South America. The most common reasons for travel included leisure (44%), VFR (18%), and mission trips (10%). Comorbidities included a history of hematologic disorders (4%), HIV infection (2%), and diabetes mellitus (3%). The average duration between vaccine administration and travel was 43 days. Those VFR were two times more likely to receive the YF vaccination <10 days before departure. Conclusions: Identifying the type of travel, itinerary, and underlying medical conditions allows providers to administer the YF vaccine to travelers safely. There is a need to identify strategies to improve the timing of YF vaccination among VFR travelers.

Management of Travel-Related Infectious Diseases in the Emergency Department

Purpose of Review

Emergency physicians generally have limited exposure to internationally acquired illnesses. However, travelers can present quite ill, and delays in recognition and treatment can lead to increased morbidity and mortality. This paper aims to summarize typical presentations of common international diseases and provide the emergency physician with a practical approach based on current guidelines.

Recent Findings

In the treatment of traveler’s diarrhea, azithromycin has become the treatment of choice due to the growing antibiotic resistance. Intravenous artesunate was approved in 2019 under investigational new drug protocol for the treatment of severe malaria, and artemisinin-based combination therapies (ACTs) have become the first-line treatment for most cases of uncomplicated malaria. Since the 2015 outbreak, Zika has become a concern to many travelers, but the current treatment is supportive.

Summary

Clinicians should be aware of a few noteworthy updates in the treatment of internationally acquired illnesses, but more importantly, they must recognize warning signs of severe illness and treat promptly. Future research on workup and disposition could help emergency physicians identify which patients need admission in well-appearing febrile travelers.