Hepatitis B and asymptomatic malaria coinfection in Sub-Saharan African immigrants: epidemiological and clinical features of HBV infection

INTRODUCTION

Here, we conducted an epidemiological study of hepatitis B virus (HBV) mono-infected and asymptomatic malaria/HBV coinfected immigrants and further discussed the possibility of malaria disease modifying the clinical presentation of HBV infection.

METHODS

A total of 195 African immigrants were examined for HBV infection or coinfection with HBV and asymptomatic malaria. HBV infection was diagnosed using serological tests and confirmed by PCR; furthermore, we performed a pan-Plasmodium-specific-nucleic-acid-sequence-based-amplification (NASBA) assay to detect asymptomatic malaria infection. The stage/grade of the liver disease was determined using echotomography and elastometry.

RESULTS

PCR-NASBA results confirmed that 62 of 195 subjects (31.8%) were positive for Plasmodium infection, whereas 41 of 195 subjects (21%) tested positive for HBV chronic hepatitis (HBV-DNA positive). Among the HBV-positive subjects, 26 (63.4%) of them were mono-infected patients (Group A), whereas 15 (36.6%) patients had HBV chronic hepatitis and asymptomatic malaria coinfections (Group B). The HBV-DNA median levels were 1.4×105IU/mL in HBV-mono-infected patients and 2.0×105IU/mL in coinfected patients. Echotomography and hepatic elastometry presented similar findings for both groups of patients.

CONCLUSIONS

Coinfected patients seem to present with the same clinical symptoms of the liver disease as HBV mono-infected patients.

Study of the diagnostic accuracy of microbiological techniques in the diagnosis of malaria in the immigrant population in Madrid

Background

Malaria is currently the most important human parasitic disease in the world responsible for high morbidity and mortality. Appropriate diagnostic methods are essential for early detection. Microscopy examination remains the gold standard, although molecular techniques have higher sensitivity and are very useful in cases of low parasitaemia and mixed infections. The objective of this study was to evaluate a new commercial molecular diagnostic technique.

Methods

A prospective, observational, multicentre study was performed between January 2015 and April 2017. All participants were immigrants from malaria-endemic areas, who were divided into two groups: asymptomatic group and symptomatic. Samples from both groups were evaluated by a rapid diagnostic test (ImmunoQuick^® Malaria + 4 RDT), microscopy examination, and two commercial molecular malaria tests (FTD Malaria and FTD Malaria Differentiation), then compared against an in-house reference PCR technique.

Results

In all, 250 patients were included: 164 (65.6%) in the asymptomatic group, and 86 (34.4%) in the symptomatic group. There were seven cases of asymptomatic parasitaemia (prevalence = 2.8%) that were detected only by molecular methods. In the symptomatic group, there were seven cases of submicroscopic malaria. The main species detected was Plasmodium falciparum (96.6%). The commercial molecular technique had higher sensitivity than the other methods (S = 96%) and a high rate of concordance with the in-house reference PCR technique (Kappa score = 0.93).

Conclusions

The molecular techniques, although slower than microscopy, have adequate diagnostic accuracy and are very useful for the detection of P. falciparum in cases with low parasitaemia.

Significant Decline of Malaria Incidence in Southwest of Iran (2001-2014)

Iran is considered as one of the malaria endemic countries of the Eastern Mediterranean Region (EMR) and is at risk due to neighboring Afghanistan, Pakistan in the east, and Iraq to the west. Therefore the aim of the present investigation is the evaluation of the trend of malaria distribution during the past decade (2001–2014) in Khuzestan province, southwestern Iran. In this retrospective cross-sectional investigation, blood samples were taken from all malaria suspicious cases who were referred to health centers across Khuzestan province. For each positive subject a questionnaire containing demographic information was filled out. Data analysis was performed using SPSS 18. From a total of 541 malaria confirmed cases, 498 (92.05%) were male and 43 (7.95%) were female. The highest number of infections was seen in 2001 with 161 (29.75%) cases and the lowest was in 2014 with 0 (0%). Also, Plasmodium vivax was identified as dominant species in 478 (88.35%) individuals and P. falciparum comprised 63 (11.65%). The highest infection rate was observed in non-Iranian populations with number 459 (84.85%) and imported cases 508 (93.90%). Also, the majority of subjects were over 15 years of age, 458 (84.65%). Due to proximity to endemic countries which has made the malaria campaign difficult, more effort is needed to control the infection in order to achieve malaria elimination.

High antibody responses against Plasmodium falciparum in immigrants after extended periods of interrupted exposure to malaria

BACKGROUND

Malaria immunity is commonly believed to wane in the absence of Plasmodium falciparum exposure, based on limited epidemiological data and short-lived antibody responses in some longitudinal studies in endemic areas.

METHODS

A cross-sectional study was conducted among sub-Saharan African adults residing in Spain for 1 up to 38 years (immigrants) with clinical malaria (n=55) or without malaria (n=37), naïve adults (travelers) with a first clinical malaria episode (n=20) and life-long malaria exposed adults from Mozambique (semi-immune adults) without malaria (n=27) or with clinical malaria (n=50). Blood samples were collected and IgG levels against the erythrocytic antigens AMA-1 and MSP-1₄₂ (3D7 and FVO strains), EBA-175 and DBL-α were determined by Luminex. IgG levels against antigens on the surface of infected erythrocytes (IEs) were measured by flow cytometry.

RESULTS

Immigrants without malaria had lower IgG levels than healthy semi-immune adults regardless of the antigen tested (P≤0.026), but no correlation was found between IgG levels and time since migration. Upon reinfection, immigrants with malaria had higher levels of IgG against all antigens than immigrants without malaria. However, the magnitude of the response compared to semi-immune adults with malaria depended on the antigen tested. Thus, immigrants had higher IgG levels against AMA-1 and MSP-1₄₂ (P≤0.015), similar levels against EBA-175 and DBL-α, and lower levels against IEs (P≤0.016). Immigrants had higher IgG levels against all antigens tested compared to travelers (P≤0.001), both with malaria.

CONCLUSIONS

Upon cessation of malaria exposure, IgG responses to malaria-specific antigens were maintained to a large extent, although the conservation and the magnitude of the recall response depended on the nature of the antigen. Studies on immigrant populations can shed light on the factors that determine the duration of malaria specific antibody responses and its effect on protection, with important implications for future vaccine design and public health control measures.

Cytokine profiling in immigrants with clinical malaria after extended periods of interrupted exposure to Plasmodium falciparum

Immunity to malaria is believed to wane with time in the absence of exposure to Plasmodium falciparum infection, but immunoepidemiological data on longevity of immunity remain controversial. We quantified serum cytokines and chemokines by suspension array technology as potential biomarkers for durability of immunity in immigrants with clinical malaria after years without parasite exposure. These were compared to serum/plasma profiles in naïve adults (travelers) and semi-immune adults under continuous exposure, with malaria, along with immigrant and traveler patients without malaria. Immigrants had higher levels of IL-2, IL-5 and IL-8 compared to semi-immune adults with malaria (P≤0.0200). Time since immigration correlated with increased IL-2 (rho=0.2738P=0.0495) and IFN-γ (rho=0.3044P=0.0282). However, immigrants did not show as high IFN-γ concentrations as travelers during a first malaria episode (P<0.0001). Immigrants and travelers with malaria had higher levels of IFN-γ, IL-6, and IL-10 (P<0.0100) than patients with other diseases, and IL-8 and IL-1β were elevated in immigrants with malaria (P<0.0500). Therefore, malaria patients had a characteristic strong pro-inflammatory/Th1 signature. Upon loss of exposure, control of pro-inflammatory responses and tolerance to P. falciparum appeared to be reduced. Understanding the mechanisms to maintain non-pathogenic effector responses is important to develop new malaria control strategies.

Cytokine and antibody responses to Plasmodium falciparum in naïve individuals during a first malaria episode: effect of age and malaria exposure

Age- and exposure-dependent immune responses during a malaria episode may be key to understanding the role of these factors in the acquisition of immunity to malaria. Plasma/serum samples collected from naïve Mozambican children (n=48), European adults (naïve travelers, n=22; expatriates with few prior malaria exposures, n=15) and Mozambican adults with long-life malaria exposure (n=99) during and after a malaria episode were analyzed for IgG against merozoite proteins by Luminex and against infected erythrocytes by flow cytometry. Cytokines and chemokines were analyzed in plasmas/sera by suspension array technology. No differences were detected between children and adults with a primary infection, with the exception of higher IgG levels against 3D7 MSP-1(42) (P=0.030) and a P. falciparum isolate (P=0.002), as well as higher IL-12 (P=0.020) in children compared to other groups. Compared to malaria-exposed adults, children, travelers and expatriates had higher concentrations of IFN-γ (P ≤ 0.0090), IL-2 (P ≤ 0.0379) and IL-8 (P ≤ 0.0233). Children also had higher IL-12 (P=0.0001), IL-4 (P=0.003), IL-1β (P=0.024) and TNF (P=0.006) levels compared to malaria-exposed adults. Although IL-12 was elevated in children, overall the data do not support a role of age in immune responses to a first malaria episode. A T(H)1/pro-inflammatory response was the hallmark of non-immune subjects.

Epidemiology of imported malaria among children and young adults in Barcelona (1990-2008)

Background

Increasing international travel and migration is producing changes in trends in infectious diseases, especially in children from many European cities. The objective of this study was to describe the epidemiology and determine the trends of imported malaria in patients under 20 years old in the city of Barcelona, Spain, during an 18-year period.

Methods

The study included malaria cases that were laboratory confirmed and reported to the malaria register at the Public Health Agency of Barcelona from 1990 to 2008, residing in Barcelona and less than 20 years old. Patients were classified as natives (born in Spain) or immigrants. Differences in the distribution of demographic, clinical characteristics, and incidence per 100,000 person-year evolution were analysed. Natives and immigrants were compared by logistic regression by calculating the odds ratio (OR) with a 95% confidence interval (CI) and Chi-square for a linear trend (p < 0.05).

Results

Of the total 174 cases, 143 (82.1%) were immigrants, 100 (57.5%) were female, 121 (69.5%) Plasmodium falciparum, and 108 (62.1%) were visiting friends and relatives (VFR) as the reason for travel. Among the immigrants, 99 (67.8%) were from Equatorial Guinea. Immigrant cases more frequently travelled to Africa than natives (p = 0.02). The factors associated with imported malaria among immigrant residents was travelling for VFR (OR: 6.2 CI 1.9-20.2) and age 15-19 (OR: 3.7 CI 1-13.3). The incidence increased from 1990 to 1999 (p < 0.001) and decreased from 2000 to 2008 (p = 0.01), although the global linear trend was not statistically significant (p = 0.41). The fatality rate was 0.5%.

Conclusions

The majority of cases of malaria in population less than 20 years in Barcelona were immigrants, travelling to Africa for VFR and Plasmodium falciparum was most frequently detected. The trend analysis of the entire study period did not show a statistically significant decline. It is recommended to be aware of malaria, especially among children of immigrants who travel to their parent's home country for VFR. Better access to pre travel advice should be provided.

[Imported malaria and HIV infection in Madrid. Clinical and epidemiological features]

INTRODUCTION

Few data are available in Spain data on human immunodeficiency virus (HIV) patients coinfected with malaria. This study has aimed to determine the epidemiological and clinical characteristics of imported malaria in patients coinfected with HIV.

PATIENTS AND METHODS

A case-series retrospective study was performed using the patient's medical records. The study population consisted on patients diagnosed with malaria attended in our center from january 1, 2002 to december 31, 2007.

RESULTS

A total of 484 episodes of malaria, 398 of which were included in this study, were identified. Co-infection with HIV was described in 32 cases. All of them occurred in individuals presumably with some degree of semi-immunity. In the coinfected group, there were 13 cases (40.6%) asymptomatic, whereas this event occurred in 99 cases of patients not coinfected (37.2%) (P=0.707). The greater presence of anemia in co-infected patients (62.5% vs 32.3% in non-coinfected [P=0.001]) stands out.

CONCLUSIONS

In present study, the clinical presentation forms were similar, regardless of the presence or absence of HIV infection. Although the study population does not reflect all possible scenarios of malaria and HIV coinfection, our results indicate the reality of patients attended in the Autonomous Community of Madrid.

[Imported malaria in adults. Clinical, epidemiological and analytical features]

INTRODUCTION

Up to now, the epidemiological and clinical features of imported malaria in Spain have been described in small series from general hospitals. Almost all diagnosis had been made based on symptomatic patients. The aim of this study has been to determine the epidemiological, clinical and laboratorial characteristics of imported malaria in a Reference Unit for Tropical Diseases.

PATIENTS AND METHODS

We performed a cross-sectional, observational and retrospective study. The series consisted of patients diagnosed of malaria who had been attended at the Hospital Carlos III from January 1, 2002 to December 31, 2007.

RESULTS

We identified 484 episodes of malaria, of which 398 cases were included in the analysis. Almost 50% of the patients were natives of endemic areas, while the rest were native-travelers or travelers. Most cases (88-98% according to the group) had not taken malaria chemoprophylaxis correctly when indicated. At the time of diagnosis, 30.4% of patients were asymptomatic and 28.1% of asymptomatic patients had anemia, 19.8% thrombocytopenia, 14% leukopenia, 5% hypocholesterolemia, 5% renal failure and 4.1% hypoglycemia. Low parasitemia was present in 97.5% of asymptomatic individuals compared to 80.5% of the symptomatic patients (P<0.001).

DISCUSSION

Absence of chemoprophylaxis (or poor compliance) is the main reason for malaria in individuals traveling to endemic areas. Malaria must be ruled out in individuals coming from tropical countries with compatible symptoms, and it also should be suspected in certain groups of asymptomatic individuals with abnormal laboratorial parameters.

Malaria chemoprophylaxis recommendations for immigrants to Europe, visiting relatives and friends--a Delphi method study

Background

Numbers of travellers visiting friends and relatives (VFRs) from Europe to malaria endemic countries are increasing and include long-term and second generation immigrants, who represent the major burden of malaria cases imported back into Europe. Most recommendations for malaria chemoprophylaxis lack a solid evidence base, and often fail to address the cultural, social and economic needs of VFRs.

Methods

European travel medicine experts, who are members of TropNetEurop, completed a sequential series of questionnaires according to the Delphi method. This technique aims at evaluating and developing a consensus through repeated iterations of questionnaires. The questionnaires in this study included questions about professional experience with VFRs, controversial issues in malaria prophylaxis, and 16 scenarios exploring indications for prescribing and choice of chemoprophylaxis.

Results

The experience of participants was rather diverse as was their selection of chemoprophylaxis regimen. A significant consensus was observed in only seven of 16 scenarios. The analysis revealed a wide variation in prescribing choices with preferences grouped by region of practice and increased prescribing seen in Northern Europe compared to Central Europe.

Conclusions

Improving the evidence base on efficacy, adherence to chemoprophylaxis and risk of malaria and encouraging discussion among experts, using techniques such as the Delphi method, may reduce the variability in prescription in European travel clinics.

Malaria in paradise: characterization of imported cases in Gran Canaria Island (1993-2006)

BACKGROUND

Spain obtained the official certificate of malaria eradication in 1964. However, imported malaria cases have been increasing during the last few decades in this country. This study aims to describe the clinical and epidemiological features of patients diagnosed with malaria on Gran Canaria Island.

METHODS

A retrospective study was conducted based on case review of all patients diagnosed with malaria microbiologically confirmed from 1993 to 2006, at the three referral teaching hospitals on Gran Canaria Island.

RESULTS

One hundred eighty-four episodes in 181 patients were diagnosed, 170 of them were analyzed. Most of them (82%) were travelers. Nearly 15% (14.7%) declared having had some chemoprophylaxis, but only half of them completed the treatment. Twenty cases (10.9%) were diagnosed who had just arrived as immigrants, mainly children. Malaria was acquired in Africa by 94.7% of the cases and Plasmodium falciparum was responsible for the majority of the cases (84.1%). Clinical and epidemiological differences were observed among different groups of patients formed by their origin and travel purposes. At least one indicator of severe malaria was established in 22.9% of the cases. However, global mortality was 3.8%.

CONCLUSIONS

Malaria in Gran Canaria Island is imported from endemic areas, mainly from African countries, observed mostly among young adult males, but clinical and epidemiological features may change among different groups of patients. The number of immigrants diagnosed with malaria is increasing in this area nowadays.

[Imported and non-imported diseases in the immigrant population. A decade of experience from an infectious diseases unit]

INTRODUCTION

Immigration is an inexorable process. Immigrants may suffer infectious diseases commonly seen in our environment, or those more exotic or more prevalent in their own environment.

MATERIAL AND METHODS

A study was performed including all immigrants see in an Infectious Diseases Unit of a general hospital from June 2001 to May 2010.

RESULTS

We studied 1,071 patients from Latin America (n=405, 37.8%), Northern Africa (n=281, 26.2%), Eastern Europe (n=186, 17.4%), sub-Saharan Africa (n=178, 16.6%), and Asia (21, 2.0%). Transmissible infectious diseases were the leading cause of consultation (53.8%), and they were more common among people coming from Northern Africa (61.6%) and Eastern Europe (69.4%) (P=.001). The second reason for consultation was for common infectious diseases (29%). Tropical infectious diseases were diagnosed in 16.4% of the patients, particularly from sub-Saharan Africa (36%), and Latin America (25.9%) (P<.001). The most common diagnoses were latent tuberculous infection (20.8%) [most common in those from Eastern Europe (27.4%) (P=.004)], respiratory tract infection (12.5%), sexually transmitted infections (10.6%) [most common in patients from Northern Africa (17.1%) (P=.004)], chronic hepatitis (10.4%) [most common in patients from Eastern Europe (26.3%) (P<.001) and sub-Saharan Africa (16.9%) (P=.004)], and active tuberculosis (8.7%) [most common in sub-Saharan Africa patients (15.7%) (P=.001)].

CONCLUSIONS

The spectrum of infectious diseases in the immigrant population in our area is broad, and includes a wide variety of tropical and communicable diseases, but also of common infections. While communicable diseases are the leading cause of consultation, common infections constitute an important part of health care activity.

Imported malaria in an area in southern Madrid, 2005-2008

BACKGROUND

In Spain, malaria cases are mostly due to migrants and travellers returning from endemic areas. The objective of this work was to describe the malaria cases diagnosed at the Severo Ochoa University Hospital (HUSO) in Leganés in the south of the Madrid Region from 2005 to 2008.

METHODS

Descriptive retrospective study performed at HUSO. Data sources are registries from the Microbiology Department and malaria cases notified to the Preventive Medicine Department. Analysed parameters were: administrative, demographical, related to the stay at the endemic country, clinical, microbiological diagnosis method, pregnancy, treatment and prophylaxis, co-infections, and days of hospital stay.

RESULTS

Fifty-seven patients diagnosed with malaria were studied. Case distribution per year was 13 in 2005, 15 in 2006, 15 in 2007 and 14 in 2008. Thirty-three patients were female (57.9%) and 24 male (42.1%). Mean age was 27.8 years. Most of the malaria cases were acquired in Nigeria (49.1%) and Equatorial Guinea (32.7%). 29.1% of the patients were immigrants who had arrived recently, and 61.8% acquired malaria when travelling to their countries of origin to visit friends and relatives (VFR). Majority of cases were diagnosed between June and September. Microscopy was positive in 39 cases (68.4%) immunochromatography in 42 (73.7%) and PCR in the 55 cases where performed. Plasmodium falciparum was responsible for 94.7% of the cases. The more frequent symptoms were fever (77.2%), followed by headache and gastrointestinal symptoms (33.3%). Nine cases needed hospital admittance, a pregnant woman, three children, four VFR and an African tourist, but all evolved favourably. Chemoprophylaxis data was known from 55 patients. It was taken correctly in one case (1.8%), in five (9.1%) the prophylaxis was improper while the others 49 (89.1%) cases had not followed any anti-malarial prophylaxis.

CONCLUSIONS

Children, pregnant women and the VFR have the highest risk to present severe malaria and to need hospital admittance. Another important risk factor for acquiring malaria is incorrect prophylaxis. The first place for malaria acquisition was Nigeria and the main species causing malaria was P. falciparum.

Imported malaria among African immigrants: is there still a relationship between developed countries and their ex-colonies?

Background

The objective of this study was to compare cases of imported malaria originating from the Spanish ex-colony of Equatorial Guinea (EG) with those originating from the rest of Africa (RA).

Methods

All the African cases detected in Barcelona between 1989 and 2007 were investigated in a retrospective analysis. Clinical-epidemiological variables such as sex, age, visiting friends and relatives (VFR), species, hospital admission and chemo-prophylaxis were compared. Data were analysed by logistic regression, calculating the Odds Ratio (OR) and 95% Confidence Intervals (95% CI).

Results

Of the 489 African patients, 279 (57,1%) had been born in EG and 210 (42,9%) in the rest of Africa. The cumulative incidence of imported malaria among those from EG was 179.6 per thousand inhabitants, while in those from the RA it was 33.7 per thousand (p < 0.001). Compliance with chemoprophylaxis (CP) was very low, but there were no differences between the two groups. Comparing those from EG to those from RA, the former were characterized by having more patients in the visiting friends and relatives (VFR) category, and more individuals younger than 15 years or older than 37 years, and more women. They also visited a traveller's health centre more often, had fewer hospital admissions and were less likely to reside in the inner city.

Conclusion

Cases of imported malaria originating in Africa, are more likely to come from the Spanish ex-colony of EG, and VFR are more likely to be affected. It is recommended that developed countries promote prevention programmes, such as CP advice directed at African immigrants, and develop programmes of cooperation against malaria in their ex-colonies.

Prevalence of Plasmodium spp. in malaria asymptomatic African migrants assessed by nucleic acid sequence based amplification

Background

Malaria is one of the most important infectious diseases in the world. Although most cases are found distributed in the tropical regions of Africa, Asia, Central and South Americas, there is in Europe a significant increase in the number of imported cases in non-endemic countries, in particular due to the higher mobility in today's society.

Methods

The prevalence of a possible asymptomatic infection with Plasmodium species was assessed using Nucleic Acid Sequence Based Amplification (NASBA) assays on clinical samples collected from 195 study cases with no clinical signs related to malaria and coming from sub-Saharan African regions to Southern Italy. In addition, base-line demographic, clinical and socio-economic information was collected from study participants who also underwent a full clinical examination.

Results

Sixty-two study subjects (31.8%) were found positive for Plasmodium using a pan Plasmodium specific NASBA which can detect all four Plasmodium species causing human disease, based on the small subunit 18S rRNA gene (18S NASBA). Twenty-four samples (38%) of the 62 18S NASBA positive study cases were found positive with a Pfs25 mRNA NASBA, which is specific for the detection of gametocytes of Plasmodium falciparum. A statistically significant association was observed between 18S NASBA positivity and splenomegaly, hepatomegaly and leukopaenia and country of origin.

Conclusion

This study showed that a substantial proportion of people originating from malaria endemic countries harbor malaria parasites in their blood. If transmission conditions are available, they could potentially be a reservoir. Thefore, health authorities should pay special attention to the health of this potential risk group and aim to improve their health conditions.