A Giant Scrotal Neurofibroma in a Child Masquerading as Filariasis: Uncommon Presentation of a Common Disease.

Neurofibroma of the scrotum is a very uncommon benign neoplasm, specifically when it affects teenagers and is not associated with neurofibromatosis type I. To the best of our knowledge, only a couple of cases of neurofibroma in children have been documented. Here, we report a case study of a 17-year-old boy who had a giant scrotal lump for ten years masquerading clinically as filariasis. A provisional diagnosis of benign nerve sheath neoplasm was made based on cytology findings. The lump was surgically removed from the patient, and a histopathological and immunohistochemistry examination established the diagnosis of neurofibroma. The combined clinical, preoperative cytological, histological, and immunohistochemistry findings were not presented in the literature in any of the formerly documented cases of scrotal neurofibroma. The current case expands the spectrum of differential diagnoses for scrotal tumours that clinicians have previously observed.

Filarial infections compromise influenza vaccination efficacy: Lessons from the mouse.

Helminth parasites infect more than a quarter of the human population and inflict significant changes to the immunological status of their hosts. Several human studies report impaired responses to vaccinations in helminth-infected individuals. Analysing the impact of helminth infections on the efficacy of influenza vaccinations in the mouse system helps to elucidate the underlying immunological processes. Concurrent infection with the parasitic nematode Litomosoides sigmodontis reduced the quantity and quality of antibody responses to vaccination against seasonal influenza in BALB/c and C57BL/6 mice. This led to impaired vaccination-induced protection against challenge infections with the human pathogenic 2009 pandemic H1N1 influenza A virus in helminth-infected mice. Impaired responses were also observed if vaccinations were performed after immune-driven or drug-induced clearance of a previous helminth infection. Mechanistically, the suppression was associated with a systemic and sustained expansion of IL-10-producing CD4+CD49b+LAG-3+ type 1 regulatory T cells and partially abrogated by in vivo blockade of the IL-10 receptor. In summary, these findings raise the concern that individuals in helminth-endemic areas may not always benefit from vaccinations, even in the absence of an acute and diagnosable helminth infection.

Microfilaria in cervicovaginal Pap smears: A common parasite hiding in an unusual site: Short series of four cases with literature review.

In India, filariasis is a severe and significant public health problem. It has been reported to be present in any potential site. However, cervicovaginal Pap smear cytology rarely contains microfilariae despite the widespread occurrence. The occurrence of microfilariae in cervicovaginal smears has seldom been reported, even as an accidental finding. In our retrospective study, four cases of clinically asymptomatic filariasis were diagnosed on a routine cervicovaginal Pap smear from January 2019 to July 2022. All microfilariae were characterized as Wuchereria bancrofti. In the present study, the majority of the cases present vaginal discharge, and the diagnosis was made by cytopathology. Therefore, it is crucial to consider and look for microfilariae in areas where they are not endemic.

Cytological diagnosis of microfilaria coexistent with suspected malignancy of breast and ovary in a young pregnant female.

Filariasis is a major health issue of tropical and subtropical regions and is endemic in India. It is rarely seen in cytological smears, exfoliative scrapings or in effusions. We present the case of a 29-year old female with filaria found on cytological examination of both breast and ovary.

Giraffe skin disease: Clinicopathologic characterization of cutaneous filariasis in the critically endangered Nubian giraffe (Giraffa camelopardalis camelopardalis).

Giraffe skin disease (GSD) is an emerging disease of free-ranging giraffe recognized in the last 25 years in several species, including the critically endangered Nubian giraffe (Giraffa camelopardalis camelopardalis) of Uganda. Identifying the cause of GSD and understanding its impact on health were deemed paramount to supporting these vulnerable populations. Sixty-four giraffes were immobilized in Murchison Falls National Park, Uganda, from 2017 to 2019, and GSD lesions were opportunistically biopsied. Fifty-five giraffes (86%) had GSD lesions on the neck, axilla, chest, and cranial trunk. Lesions were categorized into early, intermediary, and dormant stages based on gross and histological characteristics. Early lesions were smaller, crusted nodules with eosinophilic and pyogranulomatous dermatitis and furunculosis. Intermediary lesions were thick plaques of proliferative and fissured hyperkeratosis and acanthosis with dense dermal granulation tissue and severe eosinophilic and granulomatous dermatitis. Lesions appeared to resolve to dormancy, with dormant lesions consisting of hairless plaques of hyperkeratosis with dermal scarring and residual inflammation. The periphery of early and intermediary lesions included follicular granulomas containing adult filarid nematodes, with myriad encysted microfilariae in the superficial dermis. Stage L3 larvae were common in early and intermediary lesions, and dormant lesions had remnant encysted microfilariae with no adult or stage L3 larvae. Nematodes were morphologically and genetically novel with close identity to Stephanofilaria spp. and Brugia malayi, which cause infectious filariasis. Identification of potential insect vectors, long-term monitoring of GSD lesions, and evaluating response to therapy is ongoing in the efforts to help conserve the Nubian giraffe.

Cytological diagnosis of microfilariae in clinically unsuspected cases: A retrospective review of 12 cases.

BACKGROUND: Filariasis is a major health problem in India. Despite the high prevalence, microfilariae are rarely found in cytology smears. Most of the cases are incidentally found, solely or in association with other pathologies. AIMS AND OBJECTIVES: This study was undertaken to analyse the prevalence and cytological findings of cases of incidentally found microfilariae in cytology smears (fine needle aspiration cytology [FNAC]/exfoliative cytology) from different parts of the body. MATERIALS AND METHODS: This was a retrospective study over 3 years, in which cases of microfilariae in aspirates from swelling of different locations, body fluids, and pap smears were reviewed, and the clinicopathological data analysed. RESULTS AND ANALYSIS: Out of 11 530 cases of FNAC, 8700 cases of fluid cytology, and 9000 of conventional cervicovaginal smears, 12 cases (0.04%) of incidental findings of microfilariae were documented in cytology smears. The cases were diagnosed from lymph node (one case), hand (one case), scrotal area (one case), axilla (one case), breast (one case), subcutaneous tissue (three cases), urine (three cases), and Pap smear (one case). We found eosinophilia in one case (8.3%) of filarial lesions. We found two cases of incidental findings of microfilariae in association with malignant lesions. CONCLUSION: Cytology smear examination can play an important role in diagnosing occult filariasis in clinically unsuspected cases in association with other pathologies.

Filariasis presenting as isolated pleural effusion: A case report and mini review.

Isolated pleural effusion is a rare manifestation of filariasis that mimics tuberculosis, especially in endemic regions. We describe a case of lymphocytic and exudative pleural effusion showing microfilaria on pleural fluid cytology. A retrospective review of all cases of filarial pleural effusion reported after 2000 was conducted to evaluate the association between filariasis and pleural effusion as well as to screen the features that can help in accurate detection of these patients. The analysis suggested a causal association between the parasite and the development of pleural effusion with a high sensitivity of pleural fluid cytology for diagnosis.

Filariasis mamaria: a propósito de un caso / Breast filariasis: case report

INTRODUCCIÓN: La filariasis con afectación mamaria es una enfermedad endémica de áreas tropicales y subtropicales de África, Asia, el Pacífico y América, que afecta a unos 120 millones de personas. Aunque es una patología rara en España, dado el aumento de pacientes procedentes de dichos países, debemos conocerla para saber diagnosticarla y tratarla adecuadamente. OBJETIVO DE REPORTAR EL CASO: Dar a conocer la filariasis con afectación mamaria, sus manifestaciones clínicas y radiológicas principales, a través de un caso clínico de nuestras consultas de ginecología. DESCRIPCIÓN DEL CASO: Paciente de 43 años, procedente de Guinea Ecuatorial que acude a la consulta de Ginecología por mastalgia bilateral y aumento del volumen de las mamas de semanas de evolución. La exploración es anodina por lo que se solicita mamografía bilateral en la que describen calcificaciones compatibles con filariasis. A pesar de que el resto de pruebas fueron negativas, dada la alta sospecha clínica y radiológica se diagnosticó de filariasis mamaria. CONCLUSIONES: A pesar de la actual campaña mundial para eliminar la filariasis, el aumento de migración global incrementa la probabilidad de padecer casos importados de filariasis mamaria. Por tanto, el conocimiento de las diferentes parasitosis es imprescindible para realizar un buen diagnóstico diferencial con otras entidades clínicamente similares, e instaurar el tratamiento más adecuado.

INTRODUCTION: Breast filariasis is an endemic disease from tropical and subtropical areas of Africa, Asia, the Pacific and America affecting about 120 million people. Although it is a rare pathology in Spain, given the increase in patients from the referred countries, we must be aware of it in order to know how to diagnose and treat it properly. OBJECTIVE OF REPORTING THE CASE: To raise awareness of filariasis with breast involvement and its main clinical and radiological manifestations, through a clinical case of our gynecology consultations. CASE REPORT: 43-year-old patient from Equatorial Guinea who comes to the Gynecology consultation for bilateral mastalgia and breast enlargement of weeks of evolution. The examination is anodyne, so bilateral mammography is requested in wich calcifications compatible with filariasis are described. Despite the rest of the tests are negative, given the high clinical and radiological suspicion, the diagnosis of breast filariasis is made. CONCLUSIONS: Despite the current worldwide campaign to eliminate filariasis, the increase in global migration enhances the probability of suffering from imported cases of breast filariasis Therefore, the knowledge of the different parasitoses is essential to make a correct differential diagnosis with other clinically similar entities, and to establish the most appropriate treatment.

Microfilaria-dependent thoracic pathology associated with eosinophilic and fibrotic polyps in filaria-infected rodents.

BACKGROUND: Pulmonary manifestations are regularly reported in both human and animal filariasis. In human filariasis, the main known lung manifestations are the tropical pulmonary eosinophilia syndrome. Its duration and severity are correlated with the presence of microfilariae. Litomosoides sigmodontis is a filarial parasite residing in the pleural cavity of rodents. This model is widely used to understand the immune mechanisms that are established during infection and for the screening of therapeutic molecules. Some pulmonary manifestations during the patent phase of infection with L. sigmodontis have been described in different rodent hosts more or less permissive to infection. METHODS: Here, the permissive Mongolian gerbil (Meriones unguiculatus) was infected with L. sigmodontis. Prevalence and density of microfilariae and adult parasites were evaluated. Lungs were analyzed for pathological signatures using immunohistochemistry and 3D imaging techniques (two-photon and light sheet microscopy). RESULTS: Microfilaremia in gerbils was correlated with parasite load, as amicrofilaremic individuals had fewer parasites in their pleural cavities. Fibrotic polypoid structures were observed on both pleurae of infected gerbils. Polyps were of variable size and developed from the visceral mesothelium over the entire pleura. The larger polyps were vascularized and strongly infiltrated by immune cells such as eosinophils, macrophages or lymphocytes. The formation of these structures was induced by the presence of adult filariae since small and rare polyps were observed before patency, but they were exacerbated by the presence of gravid females and microfilariae. CONCLUSIONS: Altogether, these data emphasize the role of host-specific factors in the pathogenesis of filarial infections.

Diethylcarbamazine activates TRP channels including TRP-2 in filaria, Brugia malayi.

Diethylcarbamazine is an important classic drug used for prevention and treatment of lymphatic filariasis and loiasis, diseases caused by filarial nematodes. Despite many studies, its site of action has not been established. Until now, the consensus has been that diethylcarbamazine works by activating host immune systems, not by a direct action on the parasites. Here we show that low concentrations of diethylcarbamazine have direct and rapid (<30 s) temporary spastic paralyzing effects on the parasites that lasts around 4 h, which is produced by diethylcarbamazine opening TRP channels in muscle of Brugia malayi involving TRP-2 (TRPC-like channel subunits). GON-2 and CED-11, TRPM-like channel subunits, also contributed to diethylcarbamazine responses. Opening of these TRP channels produces contraction and subsequent activation of calcium-dependent SLO-1K channels. Recovery from the temporary paralysis is consistent with inactivation of TRP channels. Our observations elucidate mechanisms for the rapid onset and short-lasting therapeutic actions of diethylcarbamazine.

Eosinophil-Mediated Immune Control of Adult Filarial Nematode Infection Can Proceed in the Absence of IL-4 Receptor Signaling.

Helminth infections are accompanied by eosinophilia in parasitized tissues. Eosinophils are effectors of immunity to tissue helminths. We previously reported that in the context of experimental filarial nematode infection, optimum tissue eosinophil recruitment was coordinated by local macrophage populations following IL-4R-dependent in situ proliferation and alternative activation. However, in the current study, we identify that control of chronic adult filarial worm infection is evident in IL-4Rα-deficient (IL-4Rα-/-) mice, whereby the majority of infections do not achieve patency. An associated residual eosinophilia was apparent in infected IL-4Rα-/- mice. By treating IL-4Rα-/- mice serially with anti-CCR3 Ab or introducing a compound deficiency in CCR3 within IL-4Rα-/- mice, residual eosinophilia was ablated, and susceptibility to chronic adult Brugia malayi infection was established, promoting a functional role for CCR3-dependent eosinophil influx in immune control in the absence of IL-4/IL-13-dependent immune mechanisms. We investigated additional cytokine signals involved in residual eosinophilia in the absence IL-4Rα signaling and defined that IL-4Rα-/-/IL-5-/- double-knockout mice displayed significant eosinophil deficiency compared with IL-4Rα-/- mice and were susceptible to chronic fecund adult filarial infections. Contrastingly, there was no evidence that either IL-4R-dependent or IL-4R-independent/CCR3/IL-5-dependent immunity influenced B. malayi microfilarial loads in the blood. Our data demonstrate multiplicity of Th2-cytokine control of eosinophil tissue recruitment during chronic filarial infection and that IL-4R-independent/IL-5- and CCR3-dependent pathways are sufficient to control filarial adult infection via an eosinophil-dependent effector response prior to patency.

Pancytopenia: a rare cause for a common presentation.

Filariasis is a major public health hazard in tropical and subtropical countries and is endemic among the Indian population. Asymptomatic microfilariaemia, elephantiasis, acute adenolymphangitis, hydrocoele and chronic lymphatic disease are its common manifestations. We hereby report a case of microfilaria found in the bone marrow presenting as pancytopenia. There was no classical feature of elephantiasis or lymphoedema present.

Space occupying lesion of brain: An unusual site for a common infection.

Filariasis is a public health menace and is a cause for concern due to its endemicity in tropical and subtropical countries of Africa, Asia, and Western Pacific. Even in endemic areas, it is rare to find filariasis in fluid specimens especially cerebrospinal fluid. Herein, we report a case of unsuspected filarial parasitic infection in an adult male admitted as a case of space occupying lesion in brain with suspicion of lymphoma/granulomatous disease on the basis of clinicoradiological details. To the best of our knowledge, such an extensive brain involvement by filariasis has not been reported before.

Chronic infection with a tissue-invasive helminth attenuates sublethal anaphylaxis and reduces granularity and number of mast cells.

BACKGROUND: Immunoglobulin E (IgE)-mediated anaphylaxis is a potentially fatal condition in which allergy effector cells rapidly discharge pre-formed inflammatory mediators. Treatments that address the immune component of allergic anaphylaxis are inadequate. Helminths have been previously shown to suppress effector cell function; however, their ability to treat pre-existing allergy remains unclear. OBJECTIVE: To evaluate the ability of chronic helminth infection to protect against anaphylaxis in previously sensitized mice. METHODS: A sublethal model of anaphylaxis was used, in which BALB/c mice were sensitized by three intraperitoneal (i.p.) injections of OVA/alum. Temperature drop was then monitored after systemic OVA challenge in uninfected mice and in mice infected chronically with Litomosoides sigmodontis, a tissue-invasive filarial nematode. RESULTS: Litomosoides sigmodontis-infected mice exhibited significantly lower serum levels of mMCP-1 and were less hypothermic at 30-minute post-challenge compared to uninfected OVA-challenged controls. Characterization of anaphylaxis revealed that FcԑR1 and mast cells were required for hypothermia and elevated serum mMCP-1. OVA-IgE and OVA-IgG1 serum levels were not significantly altered by L sigmodontis infection, and experiments with IL-10-/- mice demonstrated that IL-10 was not required for protection against anaphylaxis. However, peritoneal mast cell numbers were significantly lower in infected mice, and those that were present exhibited decreased granularity by flow cytometry and marked depletion of intracytoplasmic granules by light microscopy. Mast cells from infected mice had lower expression of the activation markers CD200R and CD63 and contained significantly lower basal stores of histamine. CONCLUSIONS: Chronic L sigmodontis infection protects against anaphylaxis, likely due to reduction in mast cell numbers and depletion of pre-formed inflammatory mediators in remaining mast cells.

Isolated Epitrochlear Filarial Lymphadenopathy: Cytomorphological Diagnosis of an Unusual Presentation.

Filariasis is a major public health problem in tropical countries like India. Despite the large number of people at risk, detection of eggs with or without larva (microfilaria) on fine-needle aspiration cytology is very unusual, especially in an uncommon site or incidentally detected in clinically unsuspected cases of filariasis with the absence of microfilariae in the peripheral blood. A 19-year-old male presented with swelling over medial aspect of left arm (just above the elbow), with no other specific signs and symptoms. Fine needle aspiration cytology revealed an adult gravid female filarial worm in a background of reactive lymphoid cells and lymphohistiocytic clusters. We report a case with elaborate fine needle aspiration cytology findings of filarial worm infestation with unusual presentation of isolated epitrochlear lymph node involvement in a clinically unsuspected case and recommend clinicians and pathologists to consider a high index of suspicion for such infections at uncommon sites especially in endemic territories, as early diagnosis and treatment prevent the more severe manifestations of disease.

Helminth-induced Th2 cell dysfunction is distinct from exhaustion and is maintained in the absence of antigen.

T cell-intrinsic regulation, such as anergy, adaptive tolerance and exhaustion, is central to immune regulation. In contrast to Type 1 and Type 17 settings, knowledge of the intrinsic fate and function of Th2 cells in chronic Type 2 immune responses is lacking. We previously showed that Th2 cells develop a PD-1/PD-L2-dependent intrinsically hypo-responsive phenotype during infection with the filarial nematode Litomosoides sigmodontis, denoted by impaired functionality and parasite killing. This study aimed to elucidate the transcriptional changes underlying Th2 cell-intrinsic hypo-responsiveness, and whether it represents a unique and stable state of Th2 cell differentiation. We demonstrated that intrinsically hypo-responsive Th2 cells isolated from L. sigmodontis infected mice stably retained their dysfunctional Th2 phenotype upon transfer to naïve recipients, and had a divergent transcriptional profile to classical Th2 cells isolated prior to hypo-responsiveness and from mice exposed to acute Type 2 stimuli. Hypo-responsive Th2 cells displayed a distinct transcriptional profile to exhausted CD4+ T cells, but upregulated Blimp-1 and the anergy/regulatory-associated transcription factors Egr2 and c-Maf, and shared characteristics with tolerised T cells. Hypo-responsive Th2 cells increased mRNA expression of the soluble regulatory factors Fgl2, Cd38, Spp1, Areg, Metrnl, Lgals3, and Csf1, and a subset developed a T-bet+IFN-γ+ Th2/Th1 hybrid phenotype, indicating that they were not functionally inert. Contrasting with their lost ability to produce Th2 cytokines, hypo-responsive Th2 cells gained IL-21 production and IL-21R blockade enhanced resistance to L. sigmodontis. IL-21R blockade also increased the proportion of CD19+PNA+ germinal centre B cells and serum levels of parasite specific IgG1. This indicates a novel regulatory role for IL-21 during filarial infection, both in controlling protection and B cell responses. Thus, Th2 cell-intrinsic hypo-responsiveness is a distinct and stable state of Th2 cell differentiation associated with a switch from a classically active IL-4+IL-5+ Th2 phenotype, to a non-classical dysfunctional and potentially regulatory IL-21+Egr2+c-Maf+Blimp-1+IL-4loIL-5loT-bet+IFN-γ+ Th2 phenotype. This divergence towards alternate Th2 phenotypes during chronicity has broad implications for the outcomes and treatment of chronic Type 2-related infections and diseases.

Rare association of microfilaria with poorly differentiated mucin-secreting metastatic carcinoma in liver aspirate cytology.

Filariasis, a neglected tropical disease (NTD), is mainly caused by nematodes-Wuchereria bancrofti, Brugia malayi and B. timori Apart from profoundly disabling and disfiguring major clinical manifestations-lymphoedema, elephantiasis and hydrocoele-asymptomatic microfilaremia is common in endemic areas. Despite this, it is very rare to detect microfilariae in body fluids or aspirates. As per the literature search, this is the third case documenting incidental detection of microfilariae with metastatic deposits in the liver aspirate. Here, a 35-year-old man underwent image-guided fine-needle aspiration cytology of liver nodule. Liver aspirate cytology revealed poorly differentiated mucin-secreting metastatic carcinoma and coincidental presence of microfilariae of W. bancrofti Recently, microfilaria has frequently been found to be associated with the debilitated, immunocompromised condition and various neoplasm/cancer/malignancy. Hence, meticulous investigation should be undertaken to search for hidden pathology, whenever microfilariae are detected; and to deeply scrutinise aspirates for such parasites always, especially in endemic regions.

IL-4 receptor dependent expansion of lung CD169+ macrophages in microfilaria-driven inflammation.

Lung disease is regularly reported in human filarial infections but the molecular pathogenesis of pulmonary filariasis is poorly understood. We used Litomosoides sigmodontis, a rodent filaria residing in the pleural cavity responsible for pleural inflammation, to model responses to human filarial infections and probe the mechanisms. Wild-type and Th2-deficient mice (ΔdblGata1 and Il-4receptor(r)a-/-/IL-5-/-) were infected with L. sigmodontis. Survival and growth of adult filariae and prevalence and density of microfilariae were evaluated. Cells and cytokines in the pleural cavity and bronchoalveolar space were characterized by imaging, flow cytometry and ELISA. Inflammatory pathways were evaluated by transcriptomic microarrays and lungs were isolated and analyzed for histopathological signatures. 40% of WT mice were amicrofilaremic whereas almost all mutant mice display blood microfilaremia. Microfilariae induced pleural, bronchoalveolar and lung-tissue inflammation associated with an increase in bronchoalveolar eosinophils and perivascular macrophages, production of mucus, visceral pleura alterations and fibrosis. Inflammation and pathology were decreased in Th2-deficient mice. An IL-4R-dependent increase of CD169 was observed on pleural and bronchoalveolar macrophages in microfilaremic mice. CD169+ tissue-resident macrophages were identified in the lungs with specific localizations. Strikingly, CD169+ macrophages increased significantly in the perivascular area in microfilaremic mice. These data describe lung inflammation and pathology in chronic filariasis and emphasize the role of Th2 responses according to the presence of microfilariae. It is also the first report implicating CD169+ lung macrophages in response to a Nematode infection.

Microfilaria and Strongyloides larva diagnosed in cerebrospinal fluid and ascitic fluid, respectively: Approach to their morphology on cytology.

Filariasis and Strongyloidiasis are two endemic parasitic infections seen in any tropical country. Filariasis, commonly caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori is seen often in peripheral blood and lymphoid tissue. But it can be isolated from wide variety of soft tissue sites in the body like soft tissue lumps, breast, thyroid, body fluids. Strongyloides stercoralis, a helminthic infection, usually affects the respiratory and gastrointestinal (GI) tract, and frequently picked up in GI biopsies. However, in cases of hyper infection and patients with altered immunity, it can be isolated from other rare sites like body fluid samples. Accurate morphological Identification and confirmation are important for specific management. We report a case of microfilaria isolated from cerebrospinal fluid and a case of Strongyloides larva isolated from ascitic fluid in clinically unsuspected cases of these two parasitic infestations. We have also added a brief discussion on morphological differences between the two larval forms.