William M. Stauffer

Entamoeba histolytica: an update

Purpose of review Over the past decade, since it was formally recognized that Entamoeba histolytica and Entamoeba dispar were two distinct species, studies in this field have made dramatic in-roads into the understanding of E. histolytica and the pathogenesis of invasive amoebiasis. Over the same period it has also become clear that the true incidence of E. histolytica infection, particularly in vulnerable populations such as low socioeconomic children, is exceedingly high. Understanding the epidemiology, pathophysiology, and the molecular and genetic biology of the organism will not only lead to improved diagnostic and treatment options but, ultimately, to the development of a safe and efficacious vaccine. Recent findings The recent advances in the genetic and molecular sciences have increased our understanding of the mechanisms that make E. histolytica unique among enteric protozoa in causing invasive disease. In addition, host factors, which predispose individuals or populations to infection or disease, are beginning to be elucidated. New diagnostic tools specific to E. histolytica are being exploited by clinicians and researchers to identify and treat patients as well as to add to the knowledge of the epidemiology and natural history of this infection. The ultimate goal - eradication of disease - is theoretically feasible since humans and primates are the only reservoirs of E. histolytica. Many talented and dedicated individuals are pursuing the development of an effective and safe amoebiasis vaccine. Summary E. histolytica remains an important pathogen in many populations of the world and although there has been substantial progress into understanding the disease major challenges still exist.

Illness in Children After International Travel: Analysis From the GeoSentinel Surveillance Network

OBJECTIVE: By using a large, multicenter database, we investigated the characteristics and morbidities of 1591 children returning from 218 global destinations and presenting for care in 19 countries. METHODS: Data reported to the GeoSentinel Surveillance Network between January 1997 and November 2007 were analyzed, to assess demographic features, travel characteristics, and clinical diagnoses of ill pediatric travelers. Data were compared between children and adults and among 3 pediatric age groups (0–5 years, 6–11 years, and 12–17 years). RESULTS: Children were predominantly tourist travelers returning from Asia, sub-Saharan Africa, or Latin America. Compared with adults, children disproportionately presented within 7 days after return, required hospitalization, lacked pretravel health advice, and had traveled for the purpose of visiting friends and relatives. Diarrhea (28%), dermatologic conditions (25%), systemic febrile illnesses (23%), and respiratory disorders (11%) accounted for the majority of diagnoses reported for children. No fatalities were reported. Diarrhea occurred disproportionately among children after exposure to the Middle East/North Africa, dermatologic conditions after exposure to Latin America, systemic febrile illnesses after exposure to sub-Saharan Africa or Asia, and respiratory disorders after exposure to Europe or North America. The proportionate morbidity rates of travel-associated diseases differed among the pediatric age groups and between children and adults. CONCLUSIONS: The health care utilization patterns before and after travel and the profiles of travel-associated health problems differed between children and adults. Health professionals providing pretravel advice need to consider destination- and age-specific susceptibility to travel-related morbidities and develop prevention strategies accordingly.

Diagnostic Performance of Rapid Diagnostic Tests versus Blood Smears for Malaria in US Clinical Practice

BACKGROUND Approximately 4 million US travelers to developing countries are ill enough to seek health care, with 1500 malaria cases reported in the United States annually. The diagnosis of malaria is frequently delayed because of the time required to prepare malaria blood films and lack of technical expertise. An easy, reliable rapid diagnostic test (RDT) with high sensitivity and negative predictive value (NPV), particularly for Plasmodium falciparum, would be clinically useful. The objective of this study was to determine the diagnostic performance of a RDT approved by the US Food and Drug Administration compared with traditional thick and thin blood smears for malaria diagnosis. METHODS This prospective study tested 852 consecutive blood samples that underwent thick and thin smears and blinded malaria RDTs at 3 hospital laboratories during 2003-2006. Polymerase chain reaction verified positive test results and discordant results. RESULTS Malaria was noted in 95 (11%) of the 852 samples. The RDT had superior performance than the standard Giemsa thick blood smear (p = .003). The RDTs sensitivity for all malaria was 97% (92 of 95 samples), compared with 85% (81 of 95) for the blood smear, and the RDT had a superior NPV of 99.6%, compared with 98.2% for the blood smear (p = .001). The P. falciparum performance was excellent, with 100% rapid test sensitivity, compared with only 88% (65 of 74) by blood smear (p = .003). CONCLUSIONS This operational study demonstrates that the US Food and Drug Administration-approved RDT for malaria is superior to a single set of blood smears performed under routine US clinical laboratory conditions. The most valuable clinical role of the RDT is in the rapid diagnosis or the exclusion of P. falciparum malaria, which is particularly useful in outpatient settings when evaluating febrile travelers.

Screening of international immigrants, refugees, and adoptees

Frequently clinicians are faced with screening and providing preventive care to immigrants, refugees, and international adoptees. Evidence-based medicine on which to base screening protocols for these populations is lacking. It is important to review all health and vaccination records of the patient. In addition to acute symptoms, one should inquire about the symptoms of diseases prevalent in the country of origin or transit (e.g., hematuria). Many unexpected pathologic conditions may be detected by a thorough physical examination. If a reliable immunization record is presented, one need not repeat the vaccines or check titers. Remaining vaccines should be administered according to ACIP guidelines, except for certain populations (e.g., adoptees). Routine laboratory screening tests should include CBC with differential, stool for ova and parasites, urinalysis, general chemistry profile, serology for hepatitis B, and tests for HIV and syphilis. A tuberculin skin test should be performed on all immigrants, and a chest radiograph should be obtained for any patient with symptoms or a positive PPD. Lead level, hepatitis C, and TSH should be obtained for all children and most adoptees. In addition, special screening tests (e.g., for malaria, hepatitis C, and STIs) may be indicated in high-risk populations. A more organized screening system that emphasizes evidence-based and population-specific screening protocols and better communication between international, federal, state, and local levels is needed in the United States.

Multicenter Study To Evaluate the OptiMAL Test for Rapid Diagnosis of Malaria in U.S. Hospitals

ABSTRACT More than 1,000 cases of malaria are diagnosed each year in the United States. Reported numbers, however, may be artificially low because many clinicians fail to consider the diagnosis on presentation, U.S. hospital laboratory technologists have very limited experience in detecting and identifying malaria parasites, and reporting of malaria to state health departments is sporadic in many states. In this study, a rapid malaria diagnostic test, the OptiMAL test (DiaMed; under license from Flow Inc., Portland, Oreg.) was evaluated in six U.S. hospitals and compared with results of microscopy. The OptiMAL test is a 15-min rapid immunochromatographic test that both identifies and differentiates Plasmodium falciparum from non-P. falciparum malaria parasites on the basis of the detection of parasite lactate dehydrogenase in a drop of patient blood. A total of 216 specimens from patients suspected of having malaria were tested. Results indicated that 43 samples (20%) were positive for malaria parasites by microscopy (32 P. falciparum, 11 non-P. falciparum) while 42 (19%) were positive by OptiMAL (31 P. falciparum, 11 non-P. falciparum). The sensitivity of the OptiMAL test was 98%; its specificity was 100%, with positive and negative predictive values of 100 and 99%, respectively. Participating hospital physicians and laboratory directors independently reported that the OptiMAL rapid malaria test was accurate, easy to use, and well accepted by those working in their diagnostic laboratories. The overall conclusion was that integration of the OptiMAL rapid malaria test into the U.S. health care infrastructure would provide an important and easy-to-use tool for the timely diagnosis of malaria.

High-Cost Generic Drugs — Implications for Patients and Policymakers

Some older generic drugs have become very expensive, owing to factors including drug shortages, supply disruptions, and consolidations in the generic-drug industry. But generics manufacturers that legally obtain a market monopoly can also unilaterally raise prices.

Spectrum of Illness in International Migrants Seen at GeoSentinel Clinics in 1997–2009, Part 2: Migrants Resettled Internationally and Evaluated for Specific Health Concerns

BACKGROUND Increasing international migration may challenge healthcare providers unfamiliar with acute and long latency infections and diseases common in this population. This study defines health conditions encountered in a large heterogenous group of migrants. METHODS Migrants seen at GeoSentinel clinics for any reason, other than those seen at clinics only providing comprehensive protocol-based health screening soon after arrival, were included. Proportionate morbidity for syndromes and diagnoses by country or region of origin were determined and compared. RESULTS A total of 7629 migrants from 153 countries were seen at 41 GeoSentinel clinics in 19 countries. Most (59%) were adults aged 19-39 years; 11% were children. Most (58%) were seen >1 year after arrival; 27% were seen after >5 years. The most common diagnoses were latent tuberculosis (22%), viral hepatitis (17%), active tuberculosis (10%), human immunodeficiency virus (HIV)/AIDS (7%), malaria (7%), schistosomiasis (6%), and strongyloidiasis (5%); 5% were reported healthy. Twenty percent were hospitalized (24% for active tuberculosis and 21% for febrile illness [83% due to malaria]), and 13 died. Tuberculosis diagnoses and HIV/AIDS were reported from all regions, strongyloidiasis from most regions, and chronic hepatitis B virus (HBV) particularly in Asian immigrants. Regional diagnoses included schistosomiasis (Africa) and Chagas disease (Americas). CONCLUSIONS Eliciting a migration history is important at every encounter; migrant patients may have acute illness or chronic conditions related to exposure in their country of origin. Early detection and treatment, particularly for diagnoses related to tuberculosis, HBV, Strongyloides, and schistosomiasis, may improve outcomes. Policy makers should consider expansion of refugee screening programs to include all migrants.

Possible Autochthonous Malaria from Marseille to Minneapolis

We report 2 cases of Plasmodium falciparum malaria in southern France in a French woman and an American man of Togolese origin who reported no recent travel to malaria-endemic countries. Both infections occurred after a stay near Marseille, which raises the possibility of autochthonous transmission. Entomologic and genotypic investigations are described.

Profile of illness in Syrian refugees: A GeoSentinel analysis, 2013 to 2015

Screening of 488 Syrian unaccompanied minor refugees (< 18 years-old) in Berlin showed low prevalence of intestinal parasites (Giardia, 7%), positive schistosomiasis serology (1.4%) and absence of hepatitis B. Among 44 ill adult Syrian refugees examined at GeoSentinel clinics worldwide, cutaneous leishmaniasis affected one in three patients; other noteworthy infections were active tuberculosis (11%) and chronic hepatitis B or C (9%). These data can contribute to evidence-based guidelines for infectious disease screening of Syrian refugees.

Albendazole Therapy and Enteric Parasites in United States–Bound Refugees

BACKGROUND Beginning on May 1, 1999, the Centers for Disease Control and Prevention (CDC) recommended presumptive treatment of refugees for intestinal parasites with a single dose of albendazole (600 mg), administered overseas before departure for the United States. METHODS We conducted a retrospective cohort study involving 26,956 African and Southeast Asian refugees who were screened by means of microscopical examination of stool specimens for intestinal parasites on resettlement in Minnesota between 1993 and 2007. Adjusted prevalence ratios for intestinal nematodes, schistosoma species, giardia, and entamoeba were calculated among refugees who migrated before versus those who migrated after the CDC recommendation of presumptive predeparture albendazole treatment. RESULTS Among 4370 untreated refugees, 20.8% had at least one stool nematode, most commonly hookworm (in 9.2%). Among 22,586 albendazole-treated refugees, only 4.7% had one or more nematodes, most commonly trichuris (in 3.9%). After adjustment for sex, age, and region, albendazole-treated refugees were less likely than untreated refugees to have any nematodes (prevalence ratio, 0.19), ascaris (prevalence ratio, 0.06), hookworm (prevalence ratio, 0.07), or trichuris (prevalence ratio, 0.27) but were not less likely to have giardia or entamoeba. Schistosoma ova were identified exclusively among African refugees and were less prevalent among those treated with albendazole (prevalence ratio, 0.60). After implementation of the albendazole protocol, the most common pathogens among 17,011 African refugees were giardia (in 5.7%), trichuris (in 5.0%), and schistosoma (in 1.8%); among 5575 Southeast Asian refugees, only giardia remained highly prevalent (present in 17.2%). No serious adverse events associated with albendazole use were reported. CONCLUSIONS Presumptive albendazole therapy administered overseas before departure for the United States was associated with a decrease in the prevalence of intestinal nematodes among newly arrived African and Southeast Asian refugees.