Decreasing intestinal parasites in recent Northern California refugees

Status of zoonotic disease research in refugees, asylum seekers and internally displaced people, globally: A scoping review of forty clinically important zoonotic pathogens

BACKGROUND

At the end of 2022, there were over 108 million forcibly displaced people globally, including refugees, asylum seekers (AS) and internally displaced people (IDPs). Forced migration increases the risk of infectious disease transmission, and zoonotic pathogens account for 61% of emerging and re-emerging infectious diseases. Zoonoses create a high burden of disease and have the potential to cause large-scale outbreaks. This scoping review aimed to assess the state of research on a range of clinically relevant zoonotic pathogens in displaced populations in order to identify the gaps in literature and guide future research.

METHODOLOGY / PRINCIPAL FINDINGS

Literature was systematically searched to identify original research related to 40 selected zoonotic pathogens of interest in refugees, AS and IDPs. We included only peer-reviewed original research in English, with no publication date restrictions. Demographic data, migration pathways, health factors, associated outbreaks, predictive factors and preventative measures were extracted and synthesized. We identified 4,295 articles, of which 347 were included; dates of publications ranged from 1937 to 2022. Refugees were the most common population investigated (75%). Migration pathways of displaced populations increased over time towards a more complex web, involving migration in dual directions. The most frequent pathogen investigated was Schistosoma spp. (n = 99 articles). Disease outbreaks were reported in 46 publications (13.3%), with viruses being the most commonly reported pathogen type. Limited access to hygiene/sanitation, crowding and refugee status were the most commonly discussed predictors of infection. Vaccination/prophylaxis drug administration, surveillance/screening and improved hygiene/sanitation were the most commonly discussed preventative measures.

CONCLUSIONS / SIGNIFICANCE

The current research on zoonoses in displaced populations displays gaps in the spectrum of pathogens studied, as well as in the (sub)populations investigated. Future studies should be more inclusive of One Health approaches to adequately investigate the impact of zoonotic pathogens and identify transmission pathways as a basis for designing interventions for displaced populations.

The impact of neglected tropical diseases on women and girl refugees: A call for increased awareness and strategic intervention

As the number of forcibly displaced women and girls increases, it becomes ever important to recognize the negative health impacts of being displaced. Women and girl refugees are disproportionately affected by sexual and gender-based violence and mental health concerns. In addition to these health concerns in women, crowding and lack of clean water in refugee camps leads to the spread of infectious diseases in general. Neglected tropical diseases (NTDs) are infectious diseases of poverty found in tropical areas, and longstanding infections lead to significant morbidity. Particularly for women, these diseases can impact fertility, chronic disease in pregnancy, and social stigma. Despite being a high-risk group, there are minimal data on the impact of NTDs on the health of Women and girl refugees. Diseases such as schistosomiasis, soil-transmitted helminth infections, strongyloidiasis, and leishmaniasis have all been shown to affect Women and girl refugees, but the majority of these data describe NTDs in this population only after resettlement. Access to medical care with providers that are knowledgeable about NTDs while in situations of displacement as well as after third-country resettlement is crucial to their timely diagnosis and treatment to prevent longstanding sequalae. More studies in this at-risk population are needed to understand the extent of this issue and begin to work towards lasting, equitable healthcare.

Intestinal parasites in stool testing among refugees at a primary care clinic in Toronto, Canada

Background

Enteric parasites are endemic in many of the countries from which refugees originate. Clinical guidelines vary in approaches to screening for and treating intestinal parasites in refugee receiving countries. This study aims to investigate the prevalence and species of intestinal parasites identified in stool ova and parasite (O&P) specimens in a sample of newly arrived refugees in Toronto, Canada.

Methods

We conducted a retrospective chart review of 1042 refugee patients rostered at a specialized primary care clinic in Toronto from December 2011 to September 2016. Patients who completed recommended stool O&P analyses were included. Basic sociodemographic and clinical variables and results of stool O&P were examined.

Results

419 patients (40.2%) had a stool O&P positive for any protozoan or helminth species. Sixty-nine patients (6.6%) had clinically significant parasite species (excluding B hominis, D fragilis, and E dispar, given their lower risk for causing symptoms/complications): 2.3% had clinically significant protozoans and 4.2% had helminths on stool analysis.

Conclusion

Given the relatively low prevalence of clinically significant parasites identified, our findings do not support universal screening for enteric parasites with stool O&P among refugee claimants/asylum seekers. However, stool analysis should be considered in certain clinical situations, as part of a more tailored approach.

The cost-effectiveness of schistosomiasis screening and treatment among recently resettled refugees to Canada: an economic evaluation

BACKGROUND

Many refugees and asylum seekers from countries where schistosomiasis is endemic are infected with the Schistosoma parasite when they arrive in Canada. We assessed, from a systemic perspective, which of the following management strategies by health care providers is cost-effective: testing for schistosomiasis and treating if the individual is infected, treating presumptively or waiting for symptoms to emerge.

METHODS

We constructed a decision-tree model to examine the cost-effectiveness of 3 management strategies: watchful waiting, screening and treatment, and presumptive treatment. We obtained data for the model from the literature and other sources, to predict deaths and chronic complications caused by schistosomiasis, as well as costs and net monetary benefit.

RESULTS

Presumptive treatment was cost-saving if the prevalence of schistosomiasis in the target population was greater than 2.1%. In our baseline analysis, presumptive treatment was associated with an increase of 0.156 quality-adjusted life years and a cost saving of $405 per person, compared with watchful waiting. It was also more effective and less costly than screening and treatment.

INTERPRETATION

Among recently resettled refugees and asylum claimants in Canada, from countries where schistosomiasis is endemic, presumptive treatment was predicted to be less costly and more effective than watchful waiting or screening and treatment. Our results support a revision of the current Canadian recommendations.

Historical analysis of inverse correlation between soil-transmitted helminthiasis and pancreatic cancer

In this descriptive epidemiological study, the soil-transmitted helminth (STH) burden and pancreatic cancer (PC) mortality rates of different countries and peoples are compared to demonstrate an inverse correlation. Formerly ubiquitous helminth infection possibly played a significant role in defending the human host against PC until the advancement of modern hygiene, with helminth eradication in recent times in developed countries and urban centers. It is posited that a high rate of infection by STH in developing countries and rural areas protects the human host from the development of PC, possibly by immune modulation. This hypothesis is used to explain increased PC rates in minority groups in the United States who had decreased helminth exposure in the late 20th century.

Prevalence of Intestinal Parasites in a Low-Income Texas Community

Strongyloidiasis affects an estimated hundreds of millions of people worldwide, with infection possibly persisting for life without appropriate therapy because of the helminth's unique autoinfection cycle. Like other soil-transmitted helminths, because of the environmental conditions required for the life cycle of Strongyloides stercoralis, this parasite is endemic to tropical, subtropical, and temperate countries and areas with inadequate sanitation infrastructure. Given continued poverty and that nearly one in five American homes are lacking proper sanitation systems, many U.S. regions are at risk for intestinal parasites. A central Texas community was chosen as the study site, given previous reports of widespread sanitation failure, degree of poverty, and community willingness to participate. A total of 92 households were surveyed and residents tested for nine intestinal parasites using a multi-parallel quantitative real-time polymerase chain reaction and ELISA serology. From 43 stool samples, 27 (62.8%) tested positive for Blastocystis spp. and one (2.3%) for Giardia lamblia. From 97 serum samples, Strongyloides serology detected 16 (16.5%) positive individuals. These high rates of heterokont and helminthic laboratory findings in a peri-urban central Texas community suggest several key policy implications, including that strongyloidiasis should be added to the Texas notifiable conditions list, that clinical suspicion for this infection should be heightened in the region, and that residents without access to functioning and sustainable sanitation infrastructure should be provided that access as a basic human right and to promote public health.

Health Status of Asylum Seekers, Spain

The rising rate of conflicts and the unsafe situation caused by reasons of ethnicity, religion, gender, sexual orientation, political opinion, or nationality entail an increase in the number of migratory movements. The goal of this article is to describe the health status of asylum seekers visited in an international health center. We conducted a retrospective study of the asylum seekers visited between July 2013 and June 2016. A total of 303 cases were included. The median age was 28.0 years (interquartile range [IQR]: 21-35), and 203 (67.0%) were men. Of the total, 128 cases (42.2%) were from Asia, 82 (27.1%) from Eastern Europe, 42 (13.9%) from sub-Saharan Africa, 34 (11.2%) from America, and 17 (5.6%) from Maghreb. The majority, 287 (94.7%), were asymptomatic. Seventy of the 303 (23.1%) cases were diagnosed with at least one infection, this being more prevalent in men; migrants from sub-Saharan Africa; and in those who took a land-maritime migratory route. Eight of the 303 (2.6%) cases were referred to the transcultural psychiatric department. Two important challenges of the study were the communication barriers and the legal or social situation that condition the psychological symptoms. In 48 of the 303 (15.8%) cases, there was diagnosed a noncommunicable diseases. The process of care was completed by 82.5%; although 21.9% completed the vaccination for hepatitis B. The asylum seekers in this study were in general healthy young men, although special attention was given to infectious diseases with certain geoepidemiological backgrounds. Unstable living arrangements, linguistic, and cultural barriers could account for the failure of the course of care.

Parasitic stool testing in newly arrived refugees in Calgary, Alta

OBJECTIVE

To determine the prevalence of intestinal parasites and rates of stool testing compliance, as well as associated patient characteristics, among newly arrived refugees at the Mosaic Refugee Health Clinic in Calgary, Alta.

DESIGN

Retrospective chart review.

SETTING

Primary care clinic for refugee patients.

PARTICIPANTS

A total of 1390 new refugee patients at the clinic from May 1, 2011, to June 30, 2013.

MAIN OUTCOME MEASURES

Stool ova and parasite test completion and proportion of positive test results.

RESULTS

Of 1390 patients, 74.1% (95% CI 71.7% to 76.4%) completed at least 1 stool ova and parasite test. Among those completing tests, 29.7% (95% CI 26.9% to 32.6%) had at least 1 positive result. Patients aged 6 to 18 years were more likely to have positive test results (38.5%, 95% CI 32.2% to 45.0%) than patients aged 19 to 39 were, as were those last residing in Asia (36.4%, 95% CI 30.4% to 42.8%) or sub-Saharan Africa (30.9%, 95% CI 26.8% to 35.1%), compared with those arriving from the Middle East. Giardia lamblia, Blastocystis hominis, Dientamoeba fragilis, and Entamoeba histolytica or Entamoeba dispar were the most prevalent parasites. If B hominis and D fragilis are excluded because of their lower potential to cause harm, the overall prevalence was 16.3%.

CONCLUSION

Given the high compliance of patients submitting stool ova and parasite tests and a high prevalence of positive test results in some refugee groups, targeted screening should be considered in newly arrived refugees at greater risk of intestinal parasites.

Economic Analysis of the Impact of Overseas and Domestic Treatment and Screening Options for Intestinal Helminth Infection among US-Bound Refugees from Asia

BACKGROUND

Many U.S.-bound refugees travel from countries where intestinal parasites (hookworm, Trichuris trichuria, Ascaris lumbricoides, and Strongyloides stercoralis) are endemic. These infections are rare in the United States and may be underdiagnosed or misdiagnosed, leading to potentially serious consequences. This evaluation examined the costs and benefits of combinations of overseas presumptive treatment of parasitic diseases vs. domestic screening/treating vs. no program.

METHODS

An economic decision tree model terminating in Markov processes was developed to estimate the cost and health impacts of four interventions on an annual cohort of 27,700 U.S.-bound Asian refugees: 1) "No Program," 2) U.S. "Domestic Screening and Treatment," 3) "Overseas Albendazole and Ivermectin" presumptive treatment, and 4) "Overseas Albendazole and Domestic Screening for Strongyloides". Markov transition state models were used to estimate long-term effects of parasitic infections. Health outcome measures (four parasites) included outpatient cases, hospitalizations, deaths, life years, and quality-adjusted life years (QALYs).

RESULTS

The "No Program" option is the least expensive ($165,923 per cohort) and least effective option (145 outpatient cases, 4.0 hospitalizations, and 0.67 deaths discounted over a 60-year period for a one-year cohort). The "Overseas Albendazole and Ivermectin" option ($418,824) is less expensive than "Domestic Screening and Treatment" ($3,832,572) or "Overseas Albendazole and Domestic Screening for Strongyloides" ($2,182,483). According to the model outcomes, the most effective treatment option is "Overseas Albendazole and Ivermectin," which reduces outpatient cases, deaths and hospitalization by around 80% at an estimated net cost of $458,718 per death averted, or $2,219/$24,036 per QALY/life year gained relative to "No Program".

DISCUSSION

Overseas presumptive treatment for U.S.-bound refugees is a cost-effective intervention that is less expensive and at least as effective as domestic screening and treatment programs. The addition of ivermectin to albendazole reduces the prevalence of chronic strongyloidiasis and the probability of rare, but potentially fatal, disseminated strongyloidiasis.

Dientamoeba fragilis, One of the Neglected Intestinal Protozoa

Dientamoeba fragilis is a single-celled protozoan, closely related to the trichomonads. Reported worldwide as causing human gastrointestinal symptoms, D. fragilis is very common and is second only to Blastocystis spp. Dientamoebiasis equals or exceeds the incidence of giardiasis. This minireview includes diagnostic options, clinical relevance, therapy, an animal model, the confirmed cyst stage, and sequencing data. The development of a rodent model, fulfilling Koch's postulates, and the confirmation of a cyst stage have clarified transmission routes, including fecal-oral transmission. The prevalence of D. fragilis varies between 0% to over 82%; results depend on the geographic location, group studied, and diagnostic methods used.

Surveillance for parasites in unaccompanied minor refugees migrating to Germany in 2015

In 2015, most of the refugees arriving in Germany originated from countries with poor hygienic and sanitary conditions. Stool samples of 1,230 minor refugees unaccompanied by adults were investigated for possible parasites. Giardia lamblia was by far the most frequently detected parasite (n=165); all other parasites were considerably less frequent and encountered in the following order: Hymenolepis nana (n=23), Entamoeba histolytica (n=17), Trichuris trichiura (n=8), and Blastocystis hominis (n=1). Ascaris lumbricoides was not detected among any of the screened refugees. Considerable differences in prevalence rates in refugees originating from different countries could be observed.

Infectious Diseases in Sub-Saharan Immigrants to Spain

Immigrants may be carriers of infectious diseases because of the prevalence of these diseases in their country of origin, exposure during migration, or conditions during resettlement, with this prevalence being particularly high in sub-Saharan Africans. We performed a retrospective review of 180 sub-Saharan immigrants screened for infectious diseases at an International Health Center from January 2009 to December 2012. At least one pathogenic infectious disease was diagnosed in 72.8% patients: 60.6% latent tuberculosis infection, 36.8% intestinal parasites (intestinal protozoa or helminths), 28.1% helminths, 14.8% hepatitis B surface antigen positive, 1.2% anti-hepatitis C virus positive, 1.2% human immunodeficiency virus-positive, and 1.2% malaria. Coinfections were present in 28.4%. There was significant association between eosinophilia (absolute count or percentage) or hyper-IgE and the presence of helminths (P< 0.001). Relative eosinophilia and hyper-IgE were better indicators of helminth infection than absolute eosinophilia, particularly for schistosomiasis and strongyloidiasis. We found a high prevalence of infectious diseases in sub-Saharan immigrants, which could lead to severe health problems (in the absence of prompt treatment), representing a high cost to the public health system and possible transmission in the host country. Accurate screening and tailored protocols for infectious diseases are recommended in sub-Saharan immigrants.

Diabetes and Cardiovascular Disease Risk in Cambodian Refugees

To determine rates of diabetes, hypertension, and hyperlipidemia in Cambodian refugees, and to assess the proportion whose conditions are satisfactorily managed in comparison to the general population. Self-report and laboratory/physical health assessment data obtained from a household probability sample of U.S.-residing Cambodian refugees (N = 331) in 2010-2011 were compared to a probability sample of the adult U.S. population (N = 6,360) from the 2009-2010 National Health and Nutrition Examination Survey. Prevalence of diabetes, hypertension and hyperlipidemia in Cambodian refugees greatly exceeded rates found in the age- and gender-adjusted U.S.

POPULATION

Cambodian refugees with diagnosed hypertension or hyperlipidemia were less likely than their counterparts in the general U.S. population to have blood pressure and total cholesterol within recommended levels. Increased attention should be paid to prevention and management of diabetes and cardiovascular disease risk factors in the Cambodian refugee community. Research is needed to determine whether this pattern extends to other refugee groups.

Assessing enteric helminths in refugees, asylum seekers and new migrants

Currently there are 59.5million people forcibly displaced worldwide as a result of conflict, human rights violations, generalised violence or persecution. Of these, 19.5million are refugees and 1.8million are asylum seekers. Each year Australia accepts 13750 refugees through the offshore Humanitarian program, and in 2016 that number will almost double with the addition of 12000 refugees from Syria and Iraq. Many refugees have complex medical needs and have reached Australia after a difficult journey, often involving time in refugee camps and exposure to traumatic events including physical hardship and illness. Refugees often come from parts of the world where parasitic and tropical infectious diseases are prevalent and untreated. This article provides a review of enteric helminth infections in refugees, including asylum seekers and those from a refugee-like background.