Mansonella perstans causing symptomatic hypereosinophilia in a missionary family

Endomyocardial involvement in asymptomatic Latin American migrants with eosinophilia related to helminth infection: A pilot study

BACKGROUND

Hypereosinophilic syndrome can produce cardiac involvement and endomyocardial fibrosis, which have a poor prognosis. However, there is limited information regarding cardiac involvement among migrants from Latin America with eosinophilia related to helminthiasis.

METHODS

We conducted a pilot observational study where an echocardiography was performed on migrants from Latin America with both eosinophilia (>450 cells/μL) and a diagnosis of helminth infection, and on migrants from Latin America without eosinophilia or helminth infection. Microbiological techniques included a stool microscopic examination using the Ritchie's formalin-ether technique, and a specific serology to detect Strongyloides stercoralis antibodies.

RESULTS

37 participants were included, 20 with eosinophilia and 17 without eosinophilia. Twenty (54.1%) were men with a mean age of 41.3 (SD 14.3) years. Helminthic infections diagnosed in the group with eosinophilia were: 17 cases of S. stercoralis infection, 1 case of hookworm infection, and 2 cases of S. stercoralis and hookworm coinfection. Among participants with eosinophilia, echocardiographic findings revealed a greater right ventricle thickness (p = 0.001) and left atrial area and volume index (p = 0.003 and p = 0.004, respectively), while showing a lower left atrial strain (p = 0.006) and E-wave deceleration time (p = 0.008). An increase was shown in both posterior and anterior mitral leaflet thickness (p = 0.0014 and p = 0.004, respectively) when compared with participants without eosinophilia.

CONCLUSIONS

Migrants from Latin America with eosinophilia related to helminthic infections might present incipient echocardiographic alterations suggestive of early diastolic dysfunction, that could be related to eosinophilia-induced changes in the endomyocardium.

Identification and characterisation of Mansonella perstans in the Volta Region of Ghana

Mansonella spp. have been reported to have a wide global distribution. Despite the distribution and co-occurrence with other filarial parasites like Wuchereria bancrofti, Onchocerca volvulus and Loa loa, it is given little attention. There are few surveillance programmes for assessing the distribution of mansonellosis, due to the associated mild to no symptoms experienced by infected people. However, addressing this infection is critical to the onchocerciasis control program as current rapid diagnostic tools targeting O. volvulus have the tendency to cross react with Mansonella species. In this study we identified and characterised M. perstans from five sites in two districts in the Volta Region of Ghana and compared them to samples from other regions. Night blood smears and filter blood blots were obtained from individuals as part of a study on lymphatic filariasis. The Giemsa-stained smears were screened by microscopy for the presence of filarial parasites. Genomic DNA was extracted from blood blots from 39 individuals that were positive for M. perstans and Nested PCR targeting the internal spacer 1 (ITS-1) was conducted. Of these, 30 were sequenced and 24 sequences were kept for further analysis. Phylogenetic analysis of 194 nucleotide positions showed no differences in the samples collected. The similarities suggests that there could be one species in this area. However, more robust studies with larger sample sizes are required to draw such conclusions. We also observed a clustering of the samples from Ghana with reference sequences from Africa and Brazil, suggesting they could be related. This study draws further attention to a neglected infection, presents the first characterisation of M. perstans in Ghana and calls for more population-based studies across different geographical zones to ascertain species variations and disease distribution.

Prevalence and risk factors for blood filariasis among HIV-infected adults in Gabon, Central Africa: a pilot study

BACKGROUND

The level of blood filariasis parasitaemia as well as the frequency of and the relationship between cotrimoxazole prophylaxis (CTX-P), antiretroviral therapy (ART) intake and CD4 cell count among people living with human immunodeficiency virus (PLHIV) in rural areas of Gabon were being studied.

METHODS

Sociodemographic data and recent biological tests of PLHIV and HIV-negative participants were collected. Loa loa and Mansonella perstans microfilaria were detected by direct microscopy examination and leucoconcentration.

RESULTS

Overall, 209 HIV-positive and 148 HIV-negative subjects were enrolled. The overall prevalence of microfilaria was comparable between PLHIV (19.9% [n=41/206]) and HIV-negative participants (14.8% [n=22/148]) (p=0.2). The L. loa infection rate was comparable between HIV-positive (9.2%) and HIV-negative participants (6.8%) (p=0.2), while the M. perstans infection rate was 14-fold higher among PLHIV (p<0.01). L. loa parasitaemia was 6-fold lower in PLHIV receiving CTX-P (median 150 mf/mL [interquartile range {IQR} 125-350]) than in patients without (900 [550-2225]) (p<0.01). Among subjects with a CD4 cell count <200 cells/μL, the prevalence of M. perstans was 7-fold higher than that of L. loa (20.6% vs 2.9%).

CONCLUSIONS

This study suggests a similar exposure to L. loa infection of PLHIV and HIV-negative patients while M. perstans is more frequently found in HIV-positive individuals, notably those with a CD4 count <200 cells/μL.

Imported Infections with Mansonella perstans Nematodes, Italy

These infections should be included in differential diagnoses for patients with eosinophilia from disease-endemic countries.

We report 74 patients in Italy infected with Mansonella perstans nematodes, a poorly described filarial parasite. M. perstans nematodes should be included in the differential diagnosis for patients with eosinophilia from disease-endemic countries. Serologic analysis is useful for screening, and testing for microfilaremia in peripheral blood should be performed for parasite-positive patients.

Geographical distribution and species identification of human filariasis and onchocerciasis in Bioko Island, Equatorial Guinea

Human filariae are vector-borne parasites and the causative agents of various diseases, including human onchocerciasis and lymphatic filariasis. Onchocerciasis causes a spectrum of cutaneous and ophthalmologic manifestations (including blindness) and has long been a major public health problem in Bioko Island (Equatorial Guinea). Bioko Island has been included in the WHO's Onchocerciasis Control Program since 1987. In Bioko Island, the specificity and sensitivity of clinical Onchocerca volvulus diagnosis is key. The objective of this work was to update onchocerciasis elimination progress in Bioko Island, after 18 years of mass ivermectin intervention, and the general filariasis situation through a rapid and accurate molecular method. A cross-sectional study was conducted in Bioko Island from mid-January to mid-February 2014. A total of 543 subjects were included in the study. Whole blood and one skin snip (from lumbar regions) were analysed with a real time PCR assay. Two other skin biopsies were analysed by an expert microscopist. All positive samples were confirmed by sequencing. Traditional microscopic examination of the skin biopsies failed to detect any microfilariae. However, 11 (2.03%) infections were detected using PCR assay, including one O. volvulus, two Mansonella streptocerca, seven Mansonella perstans and one Loa loa infections. PCR assays in blood detected 52 filariae-positive individuals (9.6%) which harboured M. perstans or L. loa. The low prevalence of O. volvulus confirms the success of the Onchocerciasis Control Programme and suggests that Mass Drug Administration in Bioko Island can be interrupted in the near future. The very high prevalence of M. perstans found in skin snips assays raises doubts about the reliability of microscope-based diagnosis of O. volvulus infections.

Mansonellosis: current perspectives

Mansonellosis is a filarial disease caused by three species of filarial (nematode) parasites (Mansonella perstans, Mansonella streptocerca, and Mansonella ozzardi) that use humans as their main definitive hosts. These parasites are transmitted from person to person by bloodsucking females from two families of flies (Diptera). Biting midges (Ceratopogonidae) transmit all three species of Mansonella, but blackflies (Simuliidae) are also known to play a role in the transmission of M. ozzardi in parts of Latin America. M. perstans and M. streptocerca are endemic in western, eastern, and central Africa, and M. perstans is also present in the neotropical region from equatorial Brazil to the Caribbean coast. M. ozzardi has a patchy distribution in Latin America and the Caribbean. Mansonellosis infections are thought to have little pathogenicity and to be almost always asymptomatic, but occasionally causing itching, joint pains, enlarged lymph glands, and vague abdominal symptoms. In Brazil, M. ozzardi infections are also associated with corneal lesions. Diagnosis is usually performed by detecting microfilariae in peripheral blood or skin without any periodicity. There is no standard treatment at present for mansonellosis. The combination therapy of diethylcarbamazine plus mebendazole for M. perstans microfilaremia is presently one of the most widely used, but the use of ivermectin has also been proven to be very effective against microfilariae. Recently, doxycycline has shown excellent efficacy and safety when used as an antimicrobial against endosymbiotic Wolbachia bacteria harbored by some strains of M. perstans and M. ozzardi. Diethylcarbamazine and ivermectin have been used effectively to treat M. streptocerca infection. There are at present no estimates of the disease burden caused by mansonellosis, and thus its importance to many global health professionals and policy makers is presently limited to how it can interfere with diagnostic tools used in modern filarial disease control and elimination programs aimed at other species of filariae.

Endomyocardial involvement in asymptomatic sub-Saharan immigrants with helminth-related eosinophilia

Background

Among immigrants of sub-Saharan origin, parasitic infection is the leading cause of eosinophilia, which is generally interpreted as a defense mechanism. A side effect of the inflammatory mediators released by eosinophils is damage to host organs, especially the heart. The main objectives of this study were to i) assess cardiac involvement in asymptomatic sub-Saharan immigrants with eosinophilia, ii) relate the presence of lesions with the degree of eosinophilia, and iii) study the relationship between cardiac involvement and the type of causative parasite.

Methodology/Principle findings

In total, the study included 50 black immigrants (37 patients and 13 controls) from sub-Saharan Africa. In all subjects, heart structure and function were evaluated in a blinded manner using Sonos 5500 echocardiographic equipment. The findings were classified and described according to established criteria. The diagnostic criteria for helminthosis were those reported in the literature. Serum eosinophil-derived neurotoxin levels were measured using enzyme-linked immunosorbent assay. A significant association was found between the presence of eosinophilia and structural alterations (mitral valve thickening). However, the lack of an association between the degree of eosinophilia and heart valve disease and the absence of valve involvement in some patients with eosinophilia suggest the role of other factors in the appearance of endocardial lesions. There was also no association between the type of helminth and valve involvement.

Conclusions

We, therefore, suggest that transthoracic echocardiography be performed in every sub-Saharan individual with eosinophilia in order to rule out early heart valve lesions.

Endomyocardial fibrosis is characterized by fibrosis of the apical endocardium of the right ventricle, left ventricle, or both. Epidemiological studies of endomyocardial fibrosis indicate a predominance in tropical regions, with young people and men being affected predominantly. Little is known about the natural history and pathogenic factors of this condition. One of the most important factors is the presence of eosinophilia, which is mainly related to helminth infections. The aim of the study was to evaluate cardiac involvement in patients with absolute eosinophilia. We performed an echocardiographic study in asymptomatic sub-Saharan immigrants with eosinophilia and compared them with a group of control patients from the same region and of the same age. Our results suggest that eosinophilia associated with helminth infection (regardless of the causative microorganism) contributes to the asymptomatic phases of endomyocardial involvement. Treatment of these infections is simple, effective, and economical. Therefore, we suggest that all immigrant patients with eosinophilia undergo etiologic study and causal treatment as well as transthoracic echocardiography in order to rule out early damage.

Epidemiology of Mansonella perstans in the middle belt of Ghana

BACKGROUND

Mansonellosis was first reported in Ghana by Awadzi in the 1990s. Co-infections of Mansonella perstans have also been reported in a small cohort of patients with Buruli ulcer and their contacts. However, no study has assessed the exact prevalence of the disease in a larger study population. This study therefore aimed to find out the prevalence of M. perstans infection in some districts in Ghana and to determine the diversity of Culicoides that could be potential vectors for transmission.

METHODS

From each participant screened in the Asante Akim North (Ashanti Region), Sene West and Atebubu Amantin (Brong Ahafo Region) districts, a total of 70 μl of finger prick blood was collected for assessment of M. perstans microfilariae. Centre for Disease Control (CDC) light traps as well as the Human Landing Catch (HLC) method were used to assess the species diversity of Culicoides present in the study communities.

RESULTS

From 2,247 participants, an overall prevalence of 32% was recorded although up to 75% prevalence was demonstrated in some of the communities. Culicoides inornatipennis was the only species of Culicoides caught with the HLC method. By contrast, C. imicola (47%), C. neavei (25%) and C. schultzei (15%) were caught by the CDC light trap method. A wide diversity of other Culicoides spp. was also identified but correlation was only found between the prevalence of C. inornatipennis and M. perstans during the dry season.

CONCLUSIONS

Here we demonstrate for the first time that M. perstans is highly prevalent in three districts in Ghana. We found a wide spectrum of Culicoides spp. Culicoides inornatipennis was the most anthropophilic and is therefore likely to be the species responsible for transmission of infection but formal proof has yet to be obtained.

TRIAL REGISTRATION

NCT02281643 . Registered October 26, 2014. 'Retrospectively registered'.

TRIAL REGISTRY

ClinicalTrials.gov.

Mansonella, including a Potential New Species, as Common Parasites in Children in Gabon

BACKGROUND

Like other tropical African countries, Gabon is afflicted by many parasitic diseases, including filariases such as loiasis and mansonellosis. This study aimed to assess the prevalence of these two filarial diseases in febrile and afebrile children using quantitative real-time PCR and standard PCR assays coupled with sequencing.

METHODOLOGY/PRINCIPAL FINDINGS

DNA from blood specimens of 1,418 Gabonese children (1,258 febrile and 160 afebrile) were analyzed. Overall, filarial DNA was detected in 95 (6.7%) children, including 67 positive for M. perstans (4.7%), which was the most common. M. perstans was detected in 61/1,258 febrile children (4.8%) and 6/160 afebrile children (3.8%, P = 0.6). Its prevalence increased statistically with age: 3.5%, 7.7% and 10.6% in children aged ≤ 5, 6-10 and 11-15 years, respectively. M. perstans prevalence was significantly higher in Koulamoutou and Lastourville (12% and 10.5%, respectively) than in Franceville and Fougamou (2.6% and 2.4%, respectively). Loa loa was detected in seven febrile children including one co-infection with M. perstans. Finally, 21 filarial DNA positive were negative for M. perstans and Loa loa, but ITS sequencing could be performed for 12 and allowed the identification of a potential new species of Mansonella provisionally called "DEUX". Mansonella sp. "DEUX" was detected only in febrile children.

CONCLUSIONS/SIGNIFICANCE

Further study should be performed to characterize Mansonella sp. "DEUX" and evaluate the clinical significance of mansonellosis in humans.

High Prevalence of Mansonella perstans Filariasis in Rural Senegal

Large parts of African and American countries are colonized by Mansonella, a very common but poorly described filarial nematode. Bloodsucking flies of the genus Culicoides are suspected to be the vector of Mansonella perstans, but no study in Senegal has confirmed that Culicoides can transmit the parasite. Designed specific real-time quantitative polymerase chain reaction (qPCR) can be used to identify microfilaria in stained blood smears. This study was performed in July and December 2010 in the southeastern Senegal, which is known to be endemic for M. perstans. We analyzed 297 blood smears from febrile and afebrile resident people by qPCR. The global prevalence of M. perstans was approximately 14.5% in both febrile and afebrile individuals. The age group of > 30 years had the highest prevalence (22.0%). No Culicoides among 1,159 studied specimens was positive for M. perstans and its vector in Senegal still requires identification.

Influence of Mansonella perstans microfilaraemia on total IgE levels in Gabonese patients co-infected with Loa loa

Mansonella (M.) perstans filariasis is widely found in Africa, including Gabon where Loa loa is also endemic. This study reports the total IgE titres according to different bioclinical forms of single or co-infection with L. loa and M. perstans in 138 patients and 20 healthy controls. The median parasite density was significantly higher in cases of loiasis. IgE titres were higher in patients with microscopic dual-infection and in the group of patients with occult loiasis plus M. perstans microfilaraemia (8425 [5292-20,679]KUI/L and 6304 [1045-10,326]KUI/L, respectively), compared to individuals with either microfilaraemic Loa loa (3368 [1414-7074]KUI/L) or Mansonella (4370 [1478-7334]KUI/L) single infections (p<0.01). IgE levels were positively correlated with M. perstans microfilaraemia (rho=0.27; p<0.01). Compared to single infections, dual M. perstans-L. loa infection induces very high total IgE titres. Studies correlating IgE titres and clinical symptoms are needed to confirm the involvement of this immunoglobulin in the pathological processes during filariasis.

Epidemiology of concomitant infection due to Loa loa and Mansonella perstans in Gabon

BACKGROUND

The filarial parasites Loa loa and Mansonnella perstans are endemic in the central and western African forest block. Loa loa is pathogenic and represents a major obstacle to the control of co-endemic filariae because its treatment can cause fatal complications such as encephalitis.

METHODOLOGY/PRINCIPAL FINDINGS

4392 individuals aged over 15 years were studied both by direct examination and a concentration technique. The overall prevalence rates were 22.4% for Loa loa microfilaremia, 10.2% for M. perstans microfilaremia, and 3.2% for mixed infection. The prevalence of both filariae was higher in the forest ecosystem than in savannah and lakeland (p<0.0001). The intensity of microfilariae (mf) was also higher in the forest ecosystem for both parasites. The prevalence and intensity of microfilaria were both influenced by age and gender. Correlations were found between the prevalence and intensity of Loa loa microfilariae (r = 0.215 p = 0.036), and between the prevalence of Loa loa and the prevalence of individuals with microfilaria >8000 mf/ml (r = 0.624; p<0.0001) and microfilariae >30 000 mf/ml (r = 0.319, p = 0.002). In contrast, the prevalence of pruritis and Calabar swellings correlated negatively with the prevalence of Loa loa microfilaria (r = -0.219, p = 0.032; r = -0.220; p = 0.031, respectively). Pruritis, Calabar swellings and eye worm were not associated with L. loa mf intensity (r = -0.144, p = 0.162; r-0.061, p = 0.558; and r = 0.051, p = 0.624, respectively), or with the prevalence or intensity of M. perstans microfilariae.

CONCLUSIONS/SIGNIFICANCE

This map of the distribution of filariae in Gabon should prove helpful for control programs. Our findings confirm the spatial uniformity of the relationship between parasitological indices. Clinical manifestations point to a relationship between filariae and allergy.

Mansonella perstans filariasis in Africa

Mansonella perstans is a vector-borne human filarial nematode, transmitted by tiny blood-sucking flies (biting midges). It is widespread in many parts of Sub-Saharan Africa and also occurs in parts of Central and South America. Despite the commonness of this parasite very few studies have been carried out on its epidemiology and on the morbidity resulting from it, and only few thorough drug trials have been conducted to look for effective and suitable drugs and drug regimens for treatment and control. Here, we review currently available knowledge on M. perstans infections in Africa, including documented aspects of biology, vectors, transmission, diagnosis, epidemiology, morbidity and treatment. It is concluded that there is an urgent need for more research on this widespread but greatly neglected infection in order to properly assess its public health significance and as a background for identifying and recommending optimal means and strategies for treatment and control.

[Filarial infestation in patients emanating from endemic area. 14 cases series presentation]

INTRODUCTION

The migration causes the emergence of new diseases in our environment. One of them is the filariosis which, due to the biologic cycle peculiarity, it's weird its appearance in pediatrics. This studio accomplishes a review of all the filariosis cases diagnosed the last years in an Unit specialized in Tropical Pediatrics Diseases.

MATERIAL AND METHODS

Retrospective analysis comprising 14 patients than were diagnosed with filariosis from 1995 to 2007 in the Pediatrics Unit of Carlos III Hospital (Madrid). They have been analyzed several variables to cope with clinic-epidemiological, therapeutics and evolutional characteristics.

RESULTS

All patients in the study came from Equatorial Guinea, their ages were between 3 and 15 years old. The isolated species were: 6 cases with O. volvulus, 8 with M. perstans and 2 with Loa-loa. The pruritus was the main symptom in the 71% of the cases. The eosinophilia was detected in the 78% of the patients, and the Loa-loa was the specie with higher figures. The 85% of the patients showed co-parasitation, being the intestinal the most frequent. The diagnostics was established by epidermic biopsy, microfilaremia detection, direct visualization and serology. The utilized drugs were: Mebendazole for the cases with M. perstans and Ivermectin or Dietylcarbamazine for the rest of the species. One child showed mixed filariosis. The cure was successful in the 8 cases that could be followed up.

CONCLUSIONS

We consider essential to execute a filariosis screening to every patient emanating from endemic area, especially to those with eosinophilia. The diagnostic in the childhood, even though it's difficult, it allows the prevention of the disease development, serious complications as blindness and break the parasite life cycle.