RESUMEN
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.
Asunto(s)
Mansonella , Mansoneliasis , Filogenia , Ghana/epidemiología , Mansonella/genética , Mansonella/aislamiento & purificación , Humanos , Mansoneliasis/epidemiología , Mansoneliasis/diagnóstico , Mansoneliasis/parasitología , Animales , Masculino , FemeninoRESUMEN
BACKGROUND: Mansonella perstans is among the most neglected of the neglected tropical diseases and is believed to cause more human infections than any other filarial pathogen in Africa. Based largely upon assumptions of limited infection-associated morbidity, this pathogen remains understudied, and many basic questions pertaining to its pathogenicity, distribution, prevalence, and vector-host relationships remain unanswered. However, in recent years, mounting evidence of the potential for increased Mansonella infection-associated disease has sparked a renewal in research interest. This, in turn, has produced a need for improved diagnostics, capable of providing more accurate pictures of infection prevalence, pathogen distribution, and vector-host interactions. METHODOLOGY/PRINCIPAL FINDINGS: Utilizing a previously described pipeline for the discovery of optimal molecular diagnostic targets, we identified a repetitive DNA sequence, and developed a corresponding assay, which allows for the sensitive and species-specific identification of M. perstans in human blood samples. Testing also demonstrated the ability to utilize this assay for the detection of M. perstans in field-collected mosquito samples. When testing both sample types, our repeat-targeting index assay outperformed a ribosomal sequence-targeting reference assay, facilitating the identification of additional M. perstans-positive samples falsely characterized as "negative" using the less sensitive detection method. CONCLUSIONS/SIGNIFICANCE: Through the development of an assay based upon the systematic identification of an optimal DNA target sequence, our novel diagnostic assay will provide programmatic efforts with a sensitive and specific testing platform that is capable of accurately mapping M. perstans infection and determining prevalence. Furthermore, with the added ability to identify the presence of M. perstans in mosquito samples, this assay will help to define our knowledge of the relationships that exist between this pathogen and the various geographically relevant mosquito species, which have been surmised to represent potential secondary vectors under certain conditions. Detection of M. perstans in mosquitoes will also demonstrate proof-of-concept for the mosquito-based monitoring of filarial pathogens not vectored primarily by mosquitoes, an approach expanding opportunities for integrated surveillance.
Asunto(s)
Culicidae , Mansoneliasis , Parásitos , Animales , Humanos , Mansonella/genética , Mosquitos Vectores , Genómica , Mansoneliasis/diagnóstico , Mansoneliasis/epidemiologíaRESUMEN
OBJECTIVES: Loa loa and Mansonella perstans are two very common filarial species in Africa. Although microscopy is the traditional diagnostic method for human filariasis, several polymerase chain reaction (PCR) methods have emerged as an alternative approach for identifying filarial parasites. The aim of this study is to compare three molecular methods and decide which is the most suitable for diagnosing human loiasis and mansonellosis in non-endemic regions using dried blood spot (DBS) as a medium for sample collection and storage. METHODS: A total of 100 DBS samples, with their corresponding thin and thick blood smears, were selected for this study. Microscopy was used as the reference method to diagnose and calculate the microfilaraemia. Filarial DNA was extracted using the saponin/Chelex method and the DNA isolated was assayed by Filaria-real time-PCR, filaria-nested PCR, and cytochrome oxidase I PCR. All PCR products were subsequently purified and sequenced. The statistical values for each molecular test were calculated and compared. RESULTS: Overall, 64 samples were identified as negative by all tests and a further 36 samples were positive by at least one of the methods used. The sensitivity and specificity were similar for the different molecular methods, all of which demonstrated good agreement with microscopy. CONCLUSIONS: Based on this study, and from a practical point of view (single and short amplification round), the optimal technique for diagnosing filarial infection in non-endemic regions is filaria-real time-PCR, which presents high sensitivity and specificity and is also able to detect a wide range of human filariae.
Asunto(s)
Loiasis , Mansoneliasis , Animales , Humanos , Loa/genética , Loiasis/diagnóstico , Loiasis/parasitología , Mansonella/genética , Mansoneliasis/diagnóstico , Mansoneliasis/parasitología , Reacción en Cadena de la PolimerasaRESUMEN
BACKGROUND: Infection with Mansonella perstans is a neglected filariasis, widely distributed in sub-Saharan Africa, characterized by an elusive clinical picture; treatment for mansonellosis is not standardized. This retrospective study aimed to describe the clinical features, treatment schemes and evolution, of a large cohort of imported cases of M. perstans infection seen in four European centres for tropical diseases. METHODS: Mansonella perstans infections, diagnosed by identification of blood microfilariae in migrants, expatriates and travellers, collected between 1994 and 2018, were retrospectively analysed. Data concerning demographics, clinical history and laboratory examinations at diagnosis and at follow-up time points were retrieved. RESULTS: A total of 392 patients were included in the study. Of the 281 patients for whom information on symptoms could be retrieved, 150 (53.4%) reported symptoms, abdominal pain and itching being the most frequent. Positive serology and eosinophilia were present in 84.4% and 66.1%, respectively, of those patients for whom these data were available. Concomitant parasitic infections were reported in 23.5% of patients. Treatment, administered to 325 patients (82.9%), was extremely heterogeneous between and within centres; the most commonly used regimen was mebendazole 100 mg twice a day for 1 month. A total of 256 (65.3%) patients attended a first follow-up, median 3 months (interquartile range 2-12) after the first visit; 83.1% of patients having received treatment based on mebendazole and/or doxycycline, targeting Wolbachia, became amicrofilaremic, 41.1-78.4% of whom within 12 months from single treatment. CONCLUSIONS: Lack of specific symptoms, together with the inconstant positivity of parasitological and antibody-based assays in the infected population, makes the clinical suspicion and screening for mansonellosis particularly difficult. Prospective studies evaluating prevalence of infection in migrants from endemic areas, infection-specific morbidity, presence of Wolbachia endosymbionts in M. perstans populations from different geographical areas and efficacy of treatment regimens are absolutely needed to optimize the clinical management of infection.
Asunto(s)
Mansoneliasis , Wolbachia , Animales , Humanos , Mansonella , Mansoneliasis/diagnóstico , Mansoneliasis/tratamiento farmacológico , Mansoneliasis/epidemiología , Estudios Retrospectivos , Viaje , Mebendazol/uso terapéutico , Estudios Prospectivos , Enfermedad Relacionada con los ViajesRESUMEN
BACKGROUND: Information on human filariasis in international travelers is scarce. We describe the epidemiology, clinical presentation, and outcome of these infections in a reference travel clinic over the past decades. METHODS: We reviewed all cases of filariasis diagnosed at the Institute of Tropical Medicine, Antwerp, Belgium, from 1994 to 2018. Diagnosis was obtained by either parasitological methods (confirmed) or strict clinical case definitions (probable). We assessed the characteristics of cases at diagnosis and response to therapy within 3-12 months. RESULTS: A total of 320 patients (median age: 41 years; 71% males) were diagnosed with 327 filarial infections (Wuchereria bancrofti = 6, Onchocerca volvulus = 33, Loa loa = 150, Mansonella perstans = 130, unspecified species = 8). Diagnosis was confirmed in 213/320 (67%) patients. European long-term travelers accounted for 166 patients (52%) and visitors/migrants from tropical countries for another 110 (34%). Central Africa was the likely region of acquisition for 294 (92%) patients. The number of filariasis cases decreased from 21.5/year on average in the 1990s to 6.3/year in the past decade, when loiasis became predominant. Cases reported symptoms in >80% of all filarial infections but mansonellosis (45/123 single infections; 37%). Lymphatic filariasis and onchocerciasis cases responded well to conventional therapy. However, 30% of patients with loiasis and mansonellosis experienced treatment failure (with diethylcarbamazine and levamisole-mebendazole, respectively). CONCLUSIONS: The burden and species distribution of filariasis in travelers evolved in the past decades. Most presentations were symptomatic. Case management would benefit from more effective therapies for loiasis and mansonellosis.
Asunto(s)
Filariasis Linfática , Loiasis , Mansoneliasis , Migrantes , Medicina Tropical , Adulto , Animales , Bélgica/epidemiología , Filariasis Linfática/epidemiología , Femenino , Humanos , Loiasis/diagnóstico , Loiasis/tratamiento farmacológico , Loiasis/epidemiología , Masculino , Mansoneliasis/diagnóstico , Mansoneliasis/tratamiento farmacológico , Mansoneliasis/epidemiología , Estudios RetrospectivosRESUMEN
Infections with the filarial nematodes Loa loa and Mansonella perstans are among the most neglected filarial infections. L. loa is endemic in 11 countries of Central and West Africa and loiasis is estimated to affect about 20 million people. M. perstans infection is widespread in more than 30 countries of sub-Saharan Africa. Due to the difficulty in diagnosing loiasis and M. perstans mansonellosis on a clinical basis, the diagnosis of infection with L. loa and M. perstans relies on laboratory techniques. Definitive diagnosis is based on the detection, identification, and quantification of circulating microfilariae (mf) by microscopy of concentrated blood. However, this is impractical for screening purposes as it requires expert laboratory personnel, considerable blood manipulation, and is time consuming, especially for the final issue of negative result reports, which are very common in the population visited outside endemic areas. The aim of the current work is the preliminary evaluation of the performance of the in-house real-time PCR described by Ta and colleagues compared to the routine microscopic approach for the screening of filarial infections in the clinical setting outside endemic areas, using samples from patients accessing the dedicated outpatient clinics for migrants and travelers of a reference centre for tropical diseases in Northern Italy.
Asunto(s)
Loiasis/diagnóstico , Mansoneliasis/diagnóstico , Microscopía/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Adulto , Animales , Femenino , Humanos , Masculino , Microfilarias/aislamiento & purificación , Estudios RetrospectivosRESUMEN
We reviewed Giemsa-stained thick blood smears, obtained through the national malaria surveillance program in the Amazon region of Ecuador, by light microscopy for Mansonella spp. microfilariae. Of 2,756 slides examined, 566 (20.5%) were positive. Nested PCR confirmed that the microfilariae were those of M. ozzardi nematodes, indicating that this parasite is endemic to this region.
Asunto(s)
Mansonella , Mansoneliasis/epidemiología , Mansoneliasis/parasitología , Animales , Ecuador/epidemiología , Femenino , Geografía Médica , Humanos , Masculino , Mansonella/genética , Mansonella/aislamiento & purificación , Mansoneliasis/diagnóstico , Reacción en Cadena de la Polimerasa , Prevalencia , Vigilancia en Salud PúblicaRESUMEN
Mansonelliasis is a widespread yet neglected tropical infection of humans in Africa and South America caused by the filarial nematodes, Mansonella perstans, M. ozzardi, M. rodhaini and M. streptocerca. Clinical symptoms are non-distinct and diagnosis mainly relies on the detection of microfilariae in skin or blood. Species-specific DNA repeat sequences have been used as highly sensitive biomarkers for filarial nematodes. We have developed a bioinformatic pipeline to mine Illumina reads obtained from sequencing M. perstans and M. ozzardi genomic DNA for new repeat biomarker candidates which were used to develop loop-mediated isothermal amplification (LAMP) diagnostic tests. The M. perstans assay based on the Mp419 repeat has a limit of detection of 0.1 pg, equivalent of 1/1000th of a microfilaria, while the M. ozzardi assay based on the Mo2 repeat can detect as little as 0.01 pg. Both LAMP tests possess remarkable species-specificity as they did not amplify non-target DNAs from closely related filarial species, human or vectors. We show that both assays perform successfully on infected human samples. Additionally, we demonstrate the suitability of Mp419 to detect M. perstans infection in Culicoides midges. These new tools are field deployable and suitable for the surveillance of these understudied filarial infections.
Asunto(s)
Marcadores Genéticos , Mansonella/genética , Mansoneliasis/diagnóstico , Secuencias Repetitivas de Ácidos Nucleicos , Análisis de Secuencia de ADN/métodos , África , Animales , Simulación por Computador , ADN Protozoario/genética , Pruebas Diagnósticas de Rutina , Femenino , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Masculino , Mansonella/aislamiento & purificación , Técnicas de Diagnóstico Molecular , Enfermedades Desatendidas/diagnóstico , Técnicas de Amplificación de Ácido Nucleico , Sensibilidad y Especificidad , América del SurRESUMEN
Infections due to Loa loa and Mansonella perstans 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 L. loa and M. perstans 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.
Asunto(s)
Anticuerpos Antihelmínticos/sangre , Loiasis/sangre , Mansoneliasis/sangre , Adolescente , Adulto , Animales , Ensayo de Inmunoadsorción Enzimática , Eosinófilos , Femenino , Filaricidas/uso terapéutico , Estudios de Seguimiento , Humanos , Italia , Recuento de Leucocitos , Loa , Loiasis/diagnóstico , Loiasis/tratamiento farmacológico , Estudios Longitudinales , Masculino , Mansonella , Mansoneliasis/diagnóstico , Mansoneliasis/tratamiento farmacológico , Microfilarias/aislamiento & purificación , Persona de Mediana Edad , Estudios Retrospectivos , Adulto JovenRESUMEN
BACKGROUND The human filarial worm Mansonella ozzardi is highly endemic in the large tributaries of the Amazon River. This infection is still highly neglected and can be falsely negative when microfilariae levels are low. OBJECTIVES This study investigated the frequency of individuals with M. ozzardi in riverine communities in Coari municipality, Brazilian Amazon. METHODS Different diagnostic methods including polymerase chain reaction (PCR), blood polycarbonate membrane filtration (PCMF), Knott's method (Knott), digital thick blood smears (DTBS) and venous thick blood smears (VTBS) were used to compare sensitivity and specificity among the methods. Data were analysed using PCMF and Bayesian latent class models (BLCM) as the gold standard. We used BLCM to calculate the prevalence of mansonelliasis based on the results of five diagnostic methods. FINDINGS The prevalence of mansonelliasis was 35.4% by PCMF and 30.1% by BLCM. PCR and Knott methods both possessed high sensitivity. Sensitivity relative to PCMF was 98.5% [95% confidence interval (CI): 92.0 - 99.7] for PCR and 83.5% (95% CI: 72.9 - 90.5) for Knott. Sensitivity derived by BLCM was 100% (95% CI 93.7 - 100) for PCMF, 100% (95% CI: 93.7 - 100) for PCR and 98.3% (95% CI: 90.6 - 99.9) for Knott. The odds ratio of being diagnosed as microfilaremic increased with age but did not differ between genders. Microfilariae loads were higher in subjects aged 30 - 45 and 45 - 60 years. MAIN CONCLUSIONS PCMF and PCR were the best methods to assess the prevalence of mansonelliasis in our samples. As such, using these methods could lead to higher prevalence of mansonelliasis in this region than the most commonly used method (i.e., thick blood smears).
Asunto(s)
Humanos , Cemento de Policarboxilato , Mansonella/genética , Mansoneliasis/diagnóstico , Población Rural , Brasil/epidemiología , Valor Predictivo de las Pruebas , Teorema de BayesRESUMEN
BACKGROUND: The human filarial worm Mansonella ozzardi is highly endemic in the large tributaries of the Amazon River. This infection is still highly neglected and can be falsely negative when microfilariae levels are low. OBJECTIVES: This study investigated the frequency of individuals with M. ozzardi in riverine communities in Coari municipality, Brazilian Amazon. METHODS: Different diagnostic methods including polymerase chain reaction (PCR), blood polycarbonate membrane filtration (PCMF), Knott's method (Knott), digital thick blood smears (DTBS) and venous thick blood smears (VTBS) were used to compare sensitivity and specificity among the methods. Data were analysed using PCMF and Bayesian latent class models (BLCM) as the gold standard. We used BLCM to calculate the prevalence of mansonelliasis based on the results of five diagnostic methods. FINDINGS: The prevalence of mansonelliasis was 35.4% by PCMF and 30.1% by BLCM. PCR and Knott methods both possessed high sensitivity. Sensitivity relative to PCMF was 98.5% [95% confidence interval (CI): 92.0 - 99.7] for PCR and 83.5% (95% CI: 72.9 - 90.5) for Knott. Sensitivity derived by BLCM was 100% (95% CI 93.7 - 100) for PCMF, 100% (95% CI: 93.7 - 100) for PCR and 98.3% (95% CI: 90.6 - 99.9) for Knott. The odds ratio of being diagnosed as microfilaremic increased with age but did not differ between genders. Microfilariae loads were higher in subjects aged 30 - 45 and 45 - 60 years. MAIN CONCLUSIONS: PCMF and PCR were the best methods to assess the prevalence of mansonelliasis in our samples. As such, using these methods could lead to higher prevalence of mansonelliasis in this region than the most commonly used method (i.e., thick blood smears).
Asunto(s)
Mansonella/genética , Mansoneliasis/diagnóstico , Adolescente , Adulto , Anciano , Animales , Teorema de Bayes , Brasil/epidemiología , Niño , Femenino , Filtración , Humanos , Masculino , Mansonella/aislamiento & purificación , Mansoneliasis/epidemiología , Persona de Mediana Edad , Cemento de Policarboxilato , Reacción en Cadena de la Polimerasa , Valor Predictivo de las Pruebas , Población Rural , Sensibilidad y Especificidad , Manejo de Especímenes , Adulto JovenRESUMEN
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.
Asunto(s)
Anticuerpos Antihelmínticos/sangre , Eosinofilia/diagnóstico , Mansonella/inmunología , Mansoneliasis/diagnóstico , Mansoneliasis/parasitología , Adolescente , Adulto , África del Sur del Sahara , Anciano , Animales , Niño , Preescolar , Diagnóstico Diferencial , Emigrantes e Inmigrantes , Eosinofilia/patología , Femenino , Humanos , Italia , Masculino , Mansonella/aislamiento & purificación , Mansoneliasis/inmunología , Mansoneliasis/patología , Persona de Mediana Edad , Estudios Retrospectivos , ViajeAsunto(s)
Dirofilariasis/diagnóstico , Ursidae/parasitología , Animales , Dirofilaria/clasificación , Dirofilaria/aislamiento & purificación , Dirofilariasis/sangre , Dirofilariasis/patología , Mansonella/clasificación , Mansoneliasis/diagnóstico , Mansoneliasis/veterinaria , Tipificación Molecular , Ursidae/sangreAsunto(s)
Síndrome del Túnel Carpiano/etiología , Coriorretinitis/etiología , Dermatitis/etiología , Emigración e Inmigración , Filariasis/complicaciones , Prurito/etiología , Viaje , Adulto , África , Anciano , Estudios de Cohortes , Femenino , Filariasis/diagnóstico , Filariasis/fisiopatología , Francia , Humanos , Loiasis/complicaciones , Loiasis/diagnóstico , Loiasis/fisiopatología , Masculino , Mansoneliasis/complicaciones , Mansoneliasis/diagnóstico , Mansoneliasis/fisiopatología , Persona de Mediana Edad , Oncocercosis/complicaciones , Oncocercosis/diagnóstico , Oncocercosis/fisiopatología , Estudios Retrospectivos , Adulto JovenRESUMEN
Mansonella ozzardi (Nematoda: Onchocercidae) is an understudied filarial nematode, originally described by Patrick Manson in 1897, that can be transmitted by two families of dipteran vectors, biting midges (most of them members of the genus Culicoides) and black flies (genus Simulium). With a patchy geographic distribution from southern Mexico to northwestern Argentina, human infection with M. ozzardi is highly prevalent in some of the Caribbean islands, along riverine communities in the Amazon Basin, and on both sides of the border between Bolivia and Argentina. There is no clinical entity unequivocally associated with M. ozzardi infection, although fever, arthralgia, headache, cold lower extremities, and itchy cutaneous rashes are occasionally mentioned in case report series. More recently, ocular manifestations (especially keratitis) have been associated with mansonelliasis, opening an important area of investigation. Here, we briefly review the biology, epidemiology, pathogenesis, and clinical aspects of M. ozzardi infection and point to some existing knowledge gaps, aiming to stimulate a research agenda to help filling them.
Asunto(s)
Mansonella , Mansoneliasis/epidemiología , Mansoneliasis/parasitología , Enfermedades Desatendidas/epidemiología , Enfermedades Desatendidas/parasitología , Animales , Antihelmínticos/farmacología , Antihelmínticos/uso terapéutico , Vectores Artrópodos/clasificación , Vectores Artrópodos/parasitología , Humanos , Mansonella/efectos de los fármacos , Mansonella/crecimiento & desarrollo , Mansonella/aislamiento & purificación , Mansonella/fisiología , Mansoneliasis/diagnóstico , Mansoneliasis/terapia , Enfermedades Desatendidas/diagnóstico , Enfermedades Desatendidas/terapia , PrevalenciaRESUMEN
Mansonellosis is endemic in several regions of Africa, the Caribbean, and Latin America. Mansonella ozzardi and Mansonella perstans have been reported in Latin America, including the Amazon region. A morphological and molecular microfilariae study was performed in Pauini (Brazil). Blood samples were collected from 40 individuals, and were analyzed by Giemsa-stained blood film and by two different nested polymerase chain reactions which detect internal transcribed spacer-1 and the major sperm protein gene. By microscopy, 14 of 40 were positive: 11 as M. ozzardi and three as M. perstans-like infections. Both molecular methods detected 19 positive cases as M. ozzardi, including those 14 individuals detected by microscopy, without detectable genetic differences among any of the 19 positive samples. Molecular techniques showed an improvement of mansonellosis diagnosis and may become an effective tool to evaluate the present status of M. ozzardi and M. perstans in Latin America.
Asunto(s)
Mansonella , Mansoneliasis/parasitología , Microfilarias , Animales , Brasil/epidemiología , Humanos , Mansonella/genética , Mansonella/ultraestructura , Mansoneliasis/diagnóstico , Mansoneliasis/epidemiología , Microfilarias/genética , Microfilarias/ultraestructura , Microscopía , Filogenia , Reacción en Cadena de la PolimerasaRESUMEN
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.