Stability testing of dried Plasmodium falciparum positive quality control samples for malaria rapid diagnostic tests in Liberia and Benin.

BACKGROUND: Malaria rapid diagnostic tests (RDTs) are largely responsible for the gains made in the proportion of malaria cases confirmed with a parasitological test. However, quality assurance programs to support their use remain a challenge. A dried tube specimen (DTS) method was developed that showed potential for use as a stable source of quality control (QC) sample for RDTs and for use in external quality assessments or proficiency testing (PT). DTS was further assessed with focus on sample stability under field settings in Benin and Liberia. METHODS: DTS were prepared using Plasmodium falciparum 3D7 or W2 strains at concentrations of 1000, 500 or 0 parasites/µL and tested for baseline reactivity at the Centers for Disease Control and Prevention, Atlanta before shipping. In Benin and Liberia, DTS were stored under refrigeration in a reference laboratory (RL) or in health centres under ambient temperatures. Seven rounds of testing were performed at 4-week intervals during which DTS were tested on RDTs stored at the RL or at health centres. Observed DTS reactivity at the RL and health centres were compared to expected reactivity to determine DTS stability. DTS were also assembled into a PT panel and tested by health facility staff at the mid and end time-points of the study. Daily maximum and minimum storage temperatures for RDTs and DTS were recorded. RESULTS: In Benin, DTS, irrespective of storage conditions, produced the expected reactivity at all time points. However, evidence of degradation was observed at weeks 20 and 24 for DTS stored at ambient temperatures at the health centres and not those stored under refrigeration at the RL. In Liberia, sample degradation was observed starting at week 8 especially among DTS stored at the health facilities. The degradation was associated with prolonged storage of DTS under ambient temperature prior to study commencement and less than optimal storage temperatures at the RL. Use of DTS in a PT enabled identification of health worker errors in performing the tests. CONCLUSION: DTS is a feasible tool for use as QC material and for PT under field conditions. Long-term (> 5 months) storage of DTS requires refrigeration.

Medical tourism.

Searches of the literature or Internet using the term "medical tourism" produce two sets of articles: travel for the purpose of delivering health care or travel for the purpose of seeking health care. The first usage primarily appears in the medical literature and is beyond the scope of this article, which focuses on travel to seek health care. Still, there are some aspects these two topics have in common: both are affected by ease and speed of international travel and communication associated with globalization, and both raise questions about continuity of care as well as issues related to cultural, language, and legal differences; both also raise questions about ethics. This article describes some of the motivating factors, contributing elements, and challenges in elucidating trends, as well as implications for clinicians who provide pretravel advice and those who care for ill returning travelers.

Hepatitis A among international adoptees and their contacts.

We identified 27 cases of hepatitis A among international adoptees (5 persons), their direct or indirect contacts (20 persons), and unvaccinated travelers to the adoptees' countries (2 persons). Most cases occurred among nontraveling contacts of adoptees, suggesting the need to extend prevention guidelines to include hepatitis A vaccination for at-risk nontravelers.

Travel recommendations for older adults.

Older age is an important factor in preparing travelers owing not only to physiologic changes and the increased probability of underlying medical conditions and prescription medications but also to immune status with regard to naturally acquired immunity versus immunization for vaccine-preventable diseases. Cardiovascular events (including myocardial infarctions and cerebrovascular accidents) account for most deaths abroad, followed by injuries. To plan for healthy travel, international travelers should be advised to seek care at least 4 to 6 weeks before departure. Travel medicine is a dynamic field because conditions worldwide are subject to rapid change. Clinicians must maintain a current base of knowledge if they will be regularly advising travelers or must set a threshold for referral to a travel medicine specialist.