Area of exposure and treatment challenges of malaria in Eritrean migrants: a GeoSentinel analysis

Infections with long latency in international refugees, immigrants, and migrants seen at GeoSentinel sites, 2016-2018

BACKGROUND

The continued increase in global migration compels clinicians to be aware of specific health problems faced by refugees, immigrants, and migrants (RIM). This analysis aimed to characterize RIM evaluated at GeoSentinel sites, their migration history, and infectious diseases detected through screening and diagnostic workups.

METHODS

A case report form was used to collect data on demographics, migration route, infectious diseases screened, test results, and primary infectious disease diagnosis for RIM patients seen at GeoSentinel sites. Descriptive statistics were performed.

RESULTS

Between October 2016 and November 2018, 5,319 RIM patients were evaluated at GeoSentinel sites in 19 countries. Africa was the region of birth for 2,436 patients (46 %), followed by the Americas (1,644, 31 %), and Asia (1,098, 21 %). Tuberculosis (TB) was the most common infection screened and reported as positive (853/2,273, 38 % positive by any method). TB, strongyloidiasis, and hepatitis B surface antigen positivity were observed across all migration administrative categories and regions of birth. Chagas disease was reported only among RIM patients from the Americas (393/394, 100 %) and schistosomiasis predominantly in those from Africa (480/510, 94 %). TB infection (694/5,319, 13 %) and Chagas disease (524/5,319, 10 %) were the leading primary infectious disease diagnoses.

CONCLUSIONS

Several infections of long latency (e.g. TB, hepatitis B, and strongyloidiasis) with potential for long-term sequelae were seen among RIM patients across all migration administrative categories and regions of origin. Obtaining detailed epidemiologic information from RIM patients is critical to optimize detection of diseases of individual and public health importance, particularly those with long latency periods.

A Systematic Review of Tropical Disease Prevalence among Migrants

BACKGROUND: Few studies have assessed the burden of tropical diseases among migrants into non-endemic countries. AIM: This study aimed to systematically review the existing data of the prevalence of tropical diseases globally, including neglected tropical diseases globally. MATERIALS AND METHODS: The authors conducted a systematic review reporting prevalence (including seroprevalence) of tropical diseases following the PRISMA guidelines and based on the database from PUBMED, WoS, and PROQUEST. All the identified records were screened according to the inclusion and exclusion criteria. The selected articles’ quality was appraised using the mixed methods appraisal tool to ensure its quality. RESULTS: Overall, 19 studies conducted in 13 countries published between the year 2017–2020 were included in the study. Based on the thematic analysis, two themes (type of organism) and 11 sub-themes (disease) were used. The prevalence of tropical diseases among migrants ranged from 0.2 to 31% for malaria; 3–20% for Chagas Disease; 3.2–3.5% for Giardiasis; 31.7–57.4% for Toxoplasmosis; 0.1–51%, for Schistosomiasis; 0.1–15.8%, for Strongyloidiasis; 0.3–3.8% for Trichuriasis; 0.2–0.9% for Ascariasis; 6.4–9.7% for Toxocariasis; 0.3% for Loiasis; and 0.5% for Filariasis. All migrants warrant thorough screening and testing, based on the country of origin of their last visit. Routine screening and follow-up may reduce the re-emergence of tropical disease in non-endemic countries. CONCLUSION: Multiple approaches in managing social and health issues among migrants are vital to secure healthy labor forces for the country’s economy and development. Public health sectors should implement strategic promotive, preventive, and curative programs targeted to this group.

The primate malaria parasites Plasmodium malariae, Plasmodium brasilianum and Plasmodium ovale spp.: genomic insights into distribution, dispersal and host transitions

During the twentieth century, there was an explosion in understanding of the malaria parasites infecting humans and wild primates. This was built on three main data sources: from detailed descriptive morphology, from observational histories of induced infections in captive primates, syphilis patients, prison inmates and volunteers, and from clinical and epidemiological studies in the field. All three were wholly dependent on parasitological information from blood-film microscopy, and The Primate Malarias” by Coatney and colleagues (1971) provides an overview of this knowledge available at that time. Here, 50 years on, a perspective from the third decade of the twenty-first century is presented on two pairs of primate malaria parasite species. Included is a near-exhaustive summary of the recent and current geographical distribution for each of these four species, and of the underlying molecular and genomic evidence for each. The important role of host transitions in the radiation of Plasmodium spp. is discussed, as are any implications for the desired elimination of all malaria species in human populations. Two important questions are posed, requiring further work on these often ignored taxa. Is Plasmodium brasilianum, circulating among wild simian hosts in the Americas, a distinct species from Plasmodium malariae? Can new insights into the genomic differences between Plasmodium ovale curtisi and Plasmodium ovale wallikeri be linked to any important differences in parasite morphology, cell biology or clinical and epidemiological features?

Imported malaria in Switzerland, (1990-2019): A retrospective analysis

BACKGROUND

Malaria is a life-threatening, mosquito-borne parasitic disease, caused by Plasmodium spp. It is a major public health issue. Malaria in Switzerland is primarily "imported" by infected international travellers, migrants, and asylum-seekers.

METHOD

We investigated the epidemiology and characteristics of imported malaria in Switzerland in the period between 1990 and 2019 using data from the Swiss Federal Office of Public Health (BAG). We also obtained traveller statistics from the World Tourism Organization (UNWTO).

RESULTS

During the last thirty years a total of 8'439 malaria cases and 52 deaths were reported in Switzerland. The main origin of infection was West Africa, followed by Central Africa and East Africa. The profile of malaria in migrants in Switzerland has changed, reflecting variation in migrant flows. The estimated risk of malaria in travellers sank significantly over the time frame of the study (p < 0.001, 95% CI -0.076 to -0.043).

CONCLUSIONS

Travel medicine should focus on West Africa, the main source of malaria in Switzerland. Despite most cases and all but one death being caused by Plasmodium falciparum, Plasmodium vivax remains a threat for travellers and is associated with complex prevention and therapy regimens. Public health authorities need to pre-empt the need for malaria screening, prevention and treatment based on the profile of migrant waves from malaria endemic areas including Eritrea and Afghanistan arriving in Europe.

Risk factors for and management of metronidazole-refractory giardiasis in international travellers: A retrospective analysis

BACKGROUND

Giardia lamblia is a common cause of diarrhoea in returning travellers. Failure of the recommended first-line treatment, metronidazole, has frequently been observed. Recommendations for treatment of metronidazole-refractory giardiasis lack clarity and evidence.

METHODS

We conducted a retrospective data analysis of returned travellers with confirmed giardiasis at the Bernhard-Nocht-Clinic in Hamburg, Germany, between 2007 and 2016.

RESULTS

We identified 339 cases of giardiasis, mostly acquired in South Asia (n = 157). 308 patients received metronidazole as first-line treatment, leading to treatment failure in 93 cases. Statistical analysis suggested by far the highest risk of metronidazole treatment failure for travellers returning from South Asia (Odds Ratio 8.73). Second-line therapy consisted of various different therapy regimens. Combination therapy as second-line treatment seemed to be more effective than monotherapy. A repeat course of metronidazole proved to be futile.

CONCLUSION

This study reveals a strikingly low effectiveness of metronidazole, especially in patients returning from South Asia. Second-line treatment showed inconsistency of regimens and yielded unsatisfactory results. These findings require reconsideration of treatment strategies for giardiasis. Large prospective trials are urgently needed to assess new first-line treatment options and to help implement advice for effective, agreed second-line treatment strategies. Translational projects should be created to link the understanding of resistance mechanisms with epidemiological data and clinical outcome.

Travel-related infections presenting in Europe: A 20-year analysis of EuroTravNet surveillance data

Background

Disease epidemiology of (re-)emerging infectious diseases is changing rapidly, rendering surveillance of travel-associated illness important.

Methods

We evaluated travel-related illness encountered at EuroTravNet clinics, the European surveillance sub-network of GeoSentinel, between March 1, 1998 and March 31, 2018.

Findings

103,739 ill travellers were evaluated, including 11,239 (10.8%) migrants, 89,620 (86.4%) patients seen post-travel, and 2,880 (2.8%) during and after travel. Despite increasing numbers of patient encounters over 20 years, the regions of exposure by year of clinic visits have remained stable. In 5-year increments, greater proportions of patients were migrants or visiting friends and relatives (VFR); business travel-associated illness remained stable; tourism-related illness decreased. Falciparum malaria was amongst the most-frequently diagnosed illnesses with 5,254 cases (5.1% of all patients) and the most-frequent cause of death (risk ratio versus all other illnesses 2.5:1). Animal exposures requiring rabies post-exposure prophylaxis increased from 0.7% (1998–2002) to 3.6% (2013–2018). The proportion of patients with seasonal influenza increased from zero in 1998–2002 to 0.9% in 2013–2018. There were 44 cases of viral haemorrhagic fever, most during the past five years. Arboviral infection numbers increased significantly as did the range of presenting arboviral diseases, dengue and chikungunya diagnoses increased by 2.6% and 1%, respectively.

Interpretation

Travel medicine must adapt to serve the changing profile of travellers, with an increase in migrants and persons visiting relatives and friends and the strong emergence of vector-borne diseases, with potential for further local transmission in Europe.

Funding

This project was supported by a cooperative agreement (U50CK00189) between the Centers for Disease Control and Prevention to the International Society of Travel Medicine (ISTM) and funding from the ISTM and the Public Health Agency of Canada.

GeoSentinel: past, present and future†

RATIONALE FOR REVIEW

In response to increased concerns about emerging infectious diseases, GeoSentinel, the Global Surveillance Network of the International Society of Travel Medicine in partnership with the US Centers for Disease Control and Prevention (CDC), was established in 1995 in order to serve as a global provider-based emerging infections sentinel network, conduct surveillance for travel-related infections and communicate and assist global public health responses. This review summarizes the history, past achievements and future directions of the GeoSentinel Network.

KEY FINDINGS

Funded by the US CDC in 1996, GeoSentinel has grown from a group of eight US-based travel and tropical medicine centers to a global network, which currently consists of 68 sites in 28 countries. GeoSentinel has provided important contributions that have enhanced the ability to use destination-specific differences to guide diagnosis and treatment of returning travelers, migrants and refugees. During the last two decades, GeoSentinel has identified a number of sentinel infectious disease events including previously unrecognized outbreaks and occurrence of diseases in locations thought not to harbor certain infectious agents. GeoSentinel has also provided useful insight into illnesses affecting different traveling populations such as migrants, business travelers and students, while characterizing in greater detail the epidemiology of infectious diseases such as typhoid fever, leishmaniasis and Zika virus disease.

CONCLUSIONS

Surveillance of travel- and migration-related infectious diseases has been the main focus of GeoSentinel for the last 25 years. However, GeoSentinel is now evolving into a network that will conduct both research and surveillance. The large number of participating sites and excellent geographic coverage for identification of both common and illnesses in individuals who have traversed international borders uniquely position GeoSentinel to make important contributions of travel-related infectious diseases in the years to come.

Prevalence and pattern of waterborne parasitic infections in eastern Africa: A systematic scoping review

Waterborne parasitic diseases form one of common and important public health and economic problems in low- and middle-income countries, though little is known on the burden and patterns of these diseases in most regions. This systematic scoping review informs on the prevalence and pattern of waterborne parasitic infections in eastern Africa from 1st of January 1941 to 31st of December 2019. The review found limited number of published studies on waterborne parasitic diseases, though 13 of the 15 studied countries in eastern Africa provided one or more published report(s) totalling 47 reports. Focus of studies was mainly on schistosomiasis where 44.8% of the 47 retrieved studies reported it. Other frequently reported diseases were giardiasis (23.4% of reports), soil-transmitted helminths (23.4%) and amoebiasis (21.3%). Rarely reported diseases were malaria, cryptosporidiosis, isosporiasis, dracunculiasis and trichomoniasis. Based on parasitological examinations, schistosomiasis prevalence ranged from 17 to 33% in Burundi, 1.9 to 73.9% in Ethiopia, 2.1 to 18% in Kenya, 7.2 to 88.6% in Uganda, 22.9 to 86.3% in Tanzania, 27.2 to 65.8% in Somalia, 15 to >50% in Mauritius, 2.4% in Eritrea and 5.0 to 93.7% in Madagascar. Amoebiasis prevalence was 4.6–15,3% (Ethiopia), 5.9–58.3% (Kenya), 54.5% (Rwanda), 0.7–2.7% (Sudan), 19.93% (Uganda) and 4.5–5.0% (Seychelles). Giardiasis prevalence was 0.6–55.0% (Ethiopia), 16.6% (Kenya), 3.6% (Rwanda), 21.1% (Sudan), 40.7% (Uganda), 45.0% (Eritrea) and 3.3–6.0% (Seychelles). Soil-transmitted helminths prevalence was 41.7–52.4% (Ethiopia), 32.4–40.7% (Kenya), 9997 cases (Rwanda), 85.0% (Somalia), 4.7% (Madagascar) and 1.1–84% (Seychelles), Ascaris lumbricoides, Trichuris trichiura and hookworms were the most common helminths detected. Malaria prevalence was 2.9–4.31% (Ethiopia), an annual episode of 9 million people (Sudan), 13.0% (Tanzania), 146 hospital cases (Madagascar), 1.4–2.0% (Seychelles) and <5.0% in Djibouti. It is also observed that >50% of the populations in eastern Africa region lack improved drinking water sources or sanitation facilities. This may account for the observed high prevalence of the diseases. The author also suggests likely underestimation of the prevalence as most waterborne parasitic diseases are neglected and cases likely only recorded and left unpublished in health facilities. Thus for a thorough mapping of burdens of these diseases, grey literature, including hospital records must be reviewed while interventions focusing on improved water and sanitation are likely to reduce the burden considerably.

Retrospective data analyses of social and environmental determinants of malaria control for elimination prospects in Eritrea

Background

The present study focuses on both long- and short-term malaria transmission in Eritrea and investigates the risk factors. Annual aggregates of information on malaria cases, deaths, diagnostics and control interventions from 2001 to 2008 and monthly reported data from 2009 to 2017 were obtained from the National Malaria Control Programme. We used a generalized linear regression model to examine the associations among total malaria cases, death, insecticide-treated net coverage, indoor residual spraying and climatic parameters.

Results

Reduction in malaria mortality is demonstrated by the milestone margins of over 97% by the end of 2017. Malaria incidence likewise declined during the period (from 33 to 5 per 1000 population), representing a reduction of about 86% (R² = 0.3) slightly less than the decline in mortality. The distribution of insecticide treated nets generally declined between 2001 and 2014 (R² = 0.16) before increasing from 2015 to 2017, while the number of people protected by indoor residual spraying slightly increased (R² = 0.27). Higher rainfall was significantly associated with an increased number of malaria cases. The covariates rainfall and temperature are a better pair than IRS and LLIN to predict incidences. On the other hand, IRS and LLIN is a more significant pair to predict mortality cases.

Conclusions

While Eritrea has made significant progress towards malaria elimination, this progress should be maintained and further improved. Distribution, coverage and utilization of malaria control and elimination tools should be optimized and sustained to safeguard the gains made. Additionally, consistent annual performance evaluation of malaria indicators would ensure a continuous learning process from gains/threats of epidemics and resurgence in regions already earmarked for elimination.

Imported Malaria in Countries where Malaria Is Not Endemic: a Comparison of Semi-immune and Nonimmune Travelers

The continuous increase in long-distance travel and recent large migratory movements have changed the epidemiological characteristics of imported malaria in countries where malaria is not endemic (here termed non-malaria-endemic countries). While malaria was primarily imported to nonendemic countries by returning travelers, the proportion of immigrants from malaria-endemic regions and travelers visiting friends and relatives (VFRs) in malaria-endemic countries has continued to increase. VFRs and immigrants from malaria-endemic countries now make up the majority of malaria patients in many nonendemic countries. Importantly, this group is characterized by various degrees of semi-immunity to malaria, resulting from repeated exposure to infection and a gradual decline of protection as a result of prolonged residence in non-malaria-endemic regions. Most studies indicate an effect of naturally acquired immunity in VFRs, leading to differences in the parasitological features, clinical manifestation, and odds for severe malaria and clinical complications between immune VFRs and nonimmune returning travelers. There are no valid data indicating evidence for differing algorithms for chemoprophylaxis or antimalarial treatment in semi-immune versus nonimmune malaria patients. So far, no robust biomarkers exist that properly reflect anti-parasite or clinical immunity. Until they are found, researchers should rigorously stratify their study results using surrogate markers, such as duration of time spent outside a malaria-endemic country.