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PLoS Neglected Tropical Diseases Jan 2016Mansonella perstans is a widespread, but relatively unknown human filarial parasite transmitted by Culicoides biting midges. Although it is found in many parts of...
BACKGROUND
Mansonella perstans is a widespread, but relatively unknown human filarial parasite transmitted by Culicoides biting midges. Although it is found in many parts of sub-Saharan Africa, only few studies have been carried out to deepen the understanding of its ecology, epidemiology, and health consequences. Hence, knowledge about ecological drivers of the vector and parasite distribution, integral to develop spatially explicit models for disease prevention, control, and elimination strategies, is limited.
METHODOLOGY
We analyzed data from a comprehensive nationwide survey of M. perstans infection conducted in 76 schools across Uganda in 2000-2003, to identify environmental drivers. A suite of Bayesian geostatistical regression models was fitted, and the best fitting model based on the deviance information criterion was utilized to predict M. perstans infection risk for all of Uganda. Additionally, we investigated co-infection rates and co-distribution with Wuchereria bancrofti and Plasmodium spp. infections observed at the same survey by mapping geographically overlapping areas.
PRINCIPAL FINDINGS
Several bioclimatic factors were significantly associated with M. perstans infection levels. A spatial Bayesian regression model showed the best fit, with diurnal temperature range, normalized difference vegetation index, and cattle densities identified as significant covariates. This model was employed to predict M. perstans infection risk at non-sampled locations. The level of co-infection with W. bancrofti was low (0.3%), due to limited geographic overlap. However, where the two infections did overlap geographically, a positive association was found.
CONCLUSIONS/SIGNIFICANCE
This study presents the first geostatistical risk map for M. perstans in Uganda. We confirmed a widespread distribution of M. perstans, and identified important potential drivers of risk. The results provide new insight about the ecologic preferences of this otherwise poorly known filarial parasite and its Culicoides vector species in Uganda, which might be relevant for other settings in sub-Saharan Africa.
Topics: Adolescent; Animals; Cattle; Cattle Diseases; Child; Child, Preschool; Ecosystem; Elephantiasis, Filarial; Female; Humans; Malaria; Male; Mansonella; Mansonelliasis; Uganda; Young Adult
PubMed: 26793972
DOI: 10.1371/journal.pntd.0004319 -
The American Journal of Tropical... Apr 2019Infections due to and are common yet elusive neglected filariases. Parasitological cure after treatment is very difficult to assess, as adult parasites are not... (Observational Study)
Observational Study
Infections due to and are common yet elusive neglected filariases. Parasitological cure after treatment is very difficult to assess, as adult parasites are not accessible. Therefore, outside transmission areas, patients require a long follow-up period to ascertain the therapeutic outcome, which is impractical for non-sedentary populations such as migrants. We studied the change over time of microfilaremia, eosinophil counts, and antifilarial antibodies tested with a commercial ELISA test (Bordier Affinity Products, Crissier, Switzerland), in a retrospective cohort of patients with confirmed and infections, to evaluate the role of serology in clinical practice. After treatment, all 22 eligible patients diagnosed in our center between 2015 and 2017 reached amicrofilaremia, with microfilarial counts decreasing sharply within 2 months. Paralleling eosinophil counts, antibodies decreased in all patients, 36% of whom reached sero-reversion or near-sero-reversion in < 20 months. These findings suggest that positive serology is not just residual from a past infection, and may be used for diagnosis even when microfilaremia is negative or cannot be performed. Interestingly, antibodies and eosinophil counts increased following some, but not all, re-treatment courses. If the rise in these parameters reflects death of macrofilariae, caution is required in interpreting high eosinophil counts and antibody titers shortly after treatment, as these may reflect no need for further treatment. To optimize patients' management, it is now pivotal to ascertain the interval between treatment and macrofilarial death and therefore whether re-treatments are required for complete clearance of parasites.
Topics: Adolescent; Adult; Animals; Antibodies, Helminth; Enzyme-Linked Immunosorbent Assay; Eosinophils; Female; Filaricides; Follow-Up Studies; Humans; Italy; Leukocyte Count; Loa; Loiasis; Longitudinal Studies; Male; Mansonella; Mansonelliasis; Microfilariae; Middle Aged; Retrospective Studies; Young Adult
PubMed: 30693861
DOI: 10.4269/ajtmh.18-0693 -
PLoS Neglected Tropical Diseases Nov 2015Immunochromatographic card test (ICT) is a tool to map the distribution of Wuchereria bancrofti. In areas highly endemic for loaisis in DRC and Cameroon, a relationship...
Cross-Reactivity of Filariais ICT Cards in Areas of Contrasting Endemicity of Loa loa and Mansonella perstans in Cameroon: Implications for Shrinking of the Lymphatic Filariasis Map in the Central African Region.
BACKGROUND
Immunochromatographic card test (ICT) is a tool to map the distribution of Wuchereria bancrofti. In areas highly endemic for loaisis in DRC and Cameroon, a relationship has been envisaged between high L. loa microfilaria (Mf) loads and ICT positivity. However, similar associations have not been demonstrated from other areas with contrasting levels of L. loa endemicity. This study investigated the cross-reactivity of ICT when mapping lymphatic filariasis (LF) in areas with contrasting endemicity levels of loiasis and mansonellosis in Cameroon.
METHODOLOGY/PRINCIPAL FINDINGS
A cross-sectional study to assess the prevalence and intensity of W. bancrofti, L. loa and M. perstans was carried out in 42 villages across three regions (East, North-west and South-west) of the Cameroon rainforest domain. Diurnal blood was collected from participants for the detection of circulating filarial antigen (CFA) by ICT and assessment of Mf using a thick blood smear. Clinical manifestations of LF were also assessed. ICT positives and patients clinically diagnosed with lymphoedema were further subjected to night blood collection for the detection of W. bancrofti Mf. Overall, 2190 individuals took part in the study. Overall, 24 individuals residing in 14 communities were tested positive by ICT, with prevalence rates ranging from 0% in the South-west to 2.1% in the North-west. Lymphoedema were diagnosed in 20 individuals with the majority of cases found in the North-west (11/20), and none of them were tested positive by ICT. No Mf of W. bancrofti were found in the night blood of any individual with a positive ICT result or clinical lymphoedema. Positive ICT results were strongly associated with high L. loa Mf intensity with 21 subjects having more than 8,000 L. loa Mf ml/blood (Odds ratio = 15.4; 95%CI: 6.1-39.0; p < 0.001). Similarly, a strong positive association (Spearman's rho = 0.900; p = 0.037) was observed between the prevalence of L. loa and ICT positivity by area: a rate of 1% or more of positive ICT results was found only in areas with an L. loa Mf prevalence above 15%. In contrast, there was no association between ICT positivity and M. perstans prevalence (Spearman's rho = - 0.200; p = 0.747) and Mf density (Odds ratio = 1.8; 95%CI: 0.8-4.2; p = 0.192).
CONCLUSIONS/SIGNIFICANCE
This study has confirmed the strong association between the ICT positivity and L. loa intensity (Mf/ml of blood) at the individual level. Furthermore, the study has demonstrated that ICT positivity is strongly associated with high L. loa prevalence. These results suggest that the main confounding factor for positive ICT test card results are high levels of L. loa. The findings may indicate that W. bancrofti is much less prevalent in the Central African region where L. loa is highly endemic than previously assumed and accurate re-mapping of the region would be very useful for shrinking of the map of LF distribution.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Antigens, Helminth; Cameroon; Child; Chromatography, Affinity; Cross Reactions; Cross-Sectional Studies; Elephantiasis, Filarial; Female; Humans; Loa; Loiasis; Male; Mansonelliasis; Middle Aged; Parasite Load; Rural Population; Wuchereria bancrofti; Young Adult
PubMed: 26544042
DOI: 10.1371/journal.pntd.0004184 -
Annals of Parasitology 2015The occurrence of Mansonella perstans was studied among people who had resided in Calabar metropolis for at least one year prior to the time of this study, which lasted...
The occurrence of Mansonella perstans was studied among people who had resided in Calabar metropolis for at least one year prior to the time of this study, which lasted from February to August, 2011. One thousand residents, comprising 530 males and 470 females, with an age range of 4 to 59 years, participated in the study, after an informed consent. Two millilitres of venous blood were collected at day time into EDTA bottles. The blood samples were processed by diluting 1ml of blood in 9 mls of 1% formalin and centrifuging the preparation at 3,000 revolutions per minute for 5 minutes. Deposits were left as blood smears on clean slides and after air-drying, were stained with 3% Giemsa solution for microscopy. Overall, the prevalence of Mansonella perstans was 2% (20 vs 1,000). The prevalence of the parasite among the females was 2.1% (10 vs 470) and males 1.9% (10 vs 530). Microfilaraemia only occurred among subjects aged between 25 and 45 years. The results of this study suggest that loiasis, which earned Calabar an unenviable mention in early medical literature, is no longer very prevalent in the area. Instead, a low prevalence of mansonelliasis occurs, in tandem with the existence of sparse farmlands of banana and plantain. Old stems of these crops provide suitable habitats for Culicoides species, which transmit Mansonella perstans.
Topics: Adolescent; Adult; Animals; Child; Child, Preschool; Female; Humans; Male; Mansonella; Mansonelliasis; Middle Aged; Nigeria; Young Adult
PubMed: 25911033
DOI: No ID Found -
Germs Dec 2016is a human filarial parasite transmitted by biting midges (Diptera: Ceratopogonidae) belonging to the genus and it is widely spread in sub-Saharan Africa. While most...
INTRODUCTION
is a human filarial parasite transmitted by biting midges (Diptera: Ceratopogonidae) belonging to the genus and it is widely spread in sub-Saharan Africa. While most cases are asymptomatic, mansonelliasis can be associated with angioedema, arthralgia, swellings, pain in the scrotum or in serous cavities such as the pleura, the peritoneum, the pericardium, etc. Mansonelliasis can be really hard to treat, but it has been shown that an intensive treatment using albendazole can clear the parasite.
CASE REPORT
Here we describe a case of a 16 months-old malnourished child with pneumonia due to in the east of the Democratic Republic of Congo.
CONCLUSION
Although our investigations confirmed infection, this case shows that it is very difficult to come to a conclusive diagnosis.
PubMed: 28053918
DOI: 10.11599/germs.2016.1101 -
BMC Infectious Diseases Jun 2016Human dirofilariosis is still a little known infection even in endemic areas. Dirofilariosis is zoonotic infection usually abortive in humans; instead, we report a very...
BACKGROUND
Human dirofilariosis is still a little known infection even in endemic areas. Dirofilariosis is zoonotic infection usually abortive in humans; instead, we report a very rare case (the 4th in the world), the first in Italy, in which at least two infective larvae became mature adults that mated and produced active microfilariae even though they did not reach peripheral blood.
CASE PRESENTATION
A 30-year-old Italian woman presented with a transient oedematous swelling on the left abdominal wall with a creeping eruption followed by the occurrence of a subcutaneous nodular painless mass in the iliac region. One month later, a similar temporary swelling appeared on the contralateral inguinal region associated with intermittent joint discomfort in both knees. The patient had recently travelled abroad, therefore many possible diagnoses were to be ruled out. Routine laboratory investigations revealed eosinophilia. An ultrasound examination of the iliac swelling evidenced a well-defined cyst with a big filamentous formation in continuous movement. A fine-needle aspiration of the lesion was performed for parasitological, cytological and histological exams. The prompt microscopic examination of the aspired material showed the presence of numerous microfilariae that were initially morphologically attributed to Mansonella ozzardi. Subsequently, the revision of the Giemsa stained film and molecular analyses of the biological material, allowed to identify Dirofilaria repens as etiological agent of infection.
CONCLUSIONS
We report of a case in whom microfilariae were detected in fine-needle aspirate of subcutaneous node, without evidence of microfilaraemia, and the infection failed to become fully patent. Therefore we confirm that complete development and fertilization of D. repens worms in human hosts may occur, at variance with what is commonly believed, that Dirofilaria worms cannot fully develop in humans.
Topics: Adult; Animals; Biopsy, Fine-Needle; Diagnosis, Differential; Dirofilaria repens; Dirofilariasis; Female; Humans; Italy; Lymph Nodes; Mansonella; Mansonelliasis; Microfilariae; Needles; Polymerase Chain Reaction
PubMed: 27266512
DOI: 10.1186/s12879-016-1582-3 -
PLoS Neglected Tropical Diseases May 2017
Topics: Adult; Albendazole; Animals; Anthelmintics; Doxycycline; Drug Therapy, Combination; Female; Humans; Ivermectin; Male; Mansonella; Mansonelliasis; Middle Aged; Prednisolone; Travel
PubMed: 28542192
DOI: 10.1371/journal.pntd.0005452 -
Parasites & Vectors May 2015Mansonella ozzardi is a poorly understood human filarial parasite with a broad distribution throughout Latin America. Most of what is known about its parasitism has come... (Comparative Study)
Comparative Study
A field trial of a PCR-based Mansonella ozzardi diagnosis assay detects high-levels of submicroscopic M. ozzardi infections in both venous blood samples and FTA card dried blood spots.
BACKGROUND
Mansonella ozzardi is a poorly understood human filarial parasite with a broad distribution throughout Latin America. Most of what is known about its parasitism has come from epidemiological studies that have estimated parasite incidence using light microscopy. Light microscopy can, however, miss lighter, submicroscopic, infections. In this study we have compared M. ozzardi incidence estimates made using light microscopy, with estimates made using PCR.
METHODS
214 DNA extracts made from Large Volume Venous Blood Samples (LVVBS) were taken from volunteers from two study sites in the Rio Solimões region: Codajás [n = 109] and Tefé [n = 105] and were subsequently assayed for M. ozzardi parasitism using a diagnostic PCR (Mo-dPCR). Peripheral finger-prick blood samples were taken from the same individuals and used for microscopic examination. Finger-prick blood, taken from individuals from Tefé, was also used for the creation of FTAcard dried blood spots (DBS) that were subsequently subjected to Mo-dPCR.
RESULTS
Overall M. ozzardi incidence estimates made with LVVBS PCRs were 1.8 times higher than those made using microscopy (44.9% [96/214] compared with 24.3% [52/214]) and 1.5 times higher than the PCR estimates made from FTAcard DBS (48/105 versus 31/105). PCR-based detection of FTAcard DBS proved 1.3 times more sensitive at diagnosing infections from peripheral blood samples than light microscopy did: detecting 24/105 compared with 31/105. PCR of LVVBS reported the fewest number of false negatives, detecting: 44 of 52 (84.6%) individuals diagnosed by microscopy; 27 of 31 (87.1%) of those diagnosed positive from DBSs and 17 out of 18 (94.4%) of those diagnosed as positive by both alternative methodologies.
CONCLUSIONS
In this study, Mo-dPCR of LVVBS was by far the most sensitive method of detecting M. ozzardi infections and detected submicroscopic infections. Mo-dPCR FTAcard DBS also provided a more sensitive test for M. ozzardi diagnosis than light microscopy based diagnosis did and thus in settings where only finger-prick assays can be carried-out, it may be a more reliable method of detection. Most existing M. ozzardi incidence estimates, which are often based on light microscope diagnosis, are likely to dramatically underestimate true M. ozzardi parasitism incidence levels.
Topics: Animals; Blood; Dried Blood Spot Testing; Humans; Mansonella; Mansonelliasis; Microscopy; Polymerase Chain Reaction
PubMed: 25990611
DOI: 10.1186/s13071-015-0889-z -
Revista Peruana de Medicina... 2015To determine the frequency, clinical features, and factors associated with M. ozzardi infection in volunteers of a malaria screening campaign in the district of Alto...
OBJECTIVES
To determine the frequency, clinical features, and factors associated with M. ozzardi infection in volunteers of a malaria screening campaign in the district of Alto Nanay in the Amazon jungle of Peru.
MATERIALS AND METHODS
A descriptive, analytical and cross-sectional study was performed. The participants were interviewed and examined by a physician and the data were recorded in a medical record. The diagnosis of M. ozzardi infection was performed using the method of thick blood smear and film.
RESULTS
The frequency of mansonelosis in this population was 47.8% (95% CI: 39.1 to 56.6). Through bivariate analysis we found that the report of decreased visual acuity or blurred vision and presence of subcutaneous tumors were the signs and symptoms statistically associated with the infection of microfilariae (p<0.05). Logistic regression found statistical association for residency in localities of the Pintuyacu or Alto Nanay rivers, employment in places far from the town center, the presence of subcutaneous tumors and skin thickening (p<0.05).
CONCLUSIONS
There was a high number of mansonelosis by M. ozzardi in the district of Alto Nanay which was significantly related to working outside the town center, residing in the area of the Pintuyacu River, and skin lesions.
Topics: Adolescent; Adult; Child; Child, Preschool; Cross-Sectional Studies; Female; Humans; Malaria; Male; Mansonelliasis; Middle Aged; Peru; Rivers; Volunteers; Young Adult
PubMed: 26338385
DOI: No ID Found -
The American Journal of Tropical... Jun 2016The study of the interactions among parasites within their hosts is crucial to the understanding of epidemiology of disease and for the design of effective control...
The study of the interactions among parasites within their hosts is crucial to the understanding of epidemiology of disease and for the design of effective control strategies. We have conducted an assessment of infections with Loa loa, Mansonella perstans, Wuchereria bancrofti, and Plasmodium falciparum in eastern Cameroon using a highly sensitive and specific quantitative polymerase chain reaction assay using archived dried whole blood spots. The resident population (N = 1,085) was parasitized with M. perstans (76%), L. loa (39%), and P. falciparum (33%), but not with W. bancrofti Compared with single infections (40.1%), coinfection was more common (48.8%): 21.0% had L. loa-M. perstans (Ll(+)/Mp(+)/Pf(-)), 2.7% had L. loa-P. falciparum (Ll(+)/Pf(+)/Mp(-)), 15.1% had M. perstans-P. falciparum (Mp(+)/Pf(+)/Ll(-)), and 10.0% had L. loa-M. perstans-P. falciparum (Ll(+)/Mp(+)/Pf(+)). Interestingly, those with all three infections (Ll(+)/Mp(+)/Pf(+)) had significantly higher L. loa microfilaria (mf) counts than either single Ll(+) (P = 0.004) or double Ll(+)/Mp(+) (P = 0.024) infected individuals. Of those infected with L. loa, the mean estimated counts of L. loa mf varied based on location and were positively correlated with estimated intensities of M. perstans mf. Finally, at a community level, heavy L. loa infections were concentrated in a few individuals whereby they were likely the major reservoir for infection.
Topics: Adolescent; Adult; Aged; Animals; Cameroon; Endemic Diseases; Female; Humans; Loa; Loiasis; Malaria, Falciparum; Male; Mansonella; Mansonelliasis; Middle Aged; Molecular Epidemiology; Plasmodium falciparum; Prevalence; Young Adult
PubMed: 27044568
DOI: 10.4269/ajtmh.15-0746