Emerging human pulmonary dirofilariasis in Hungary: a single center experience.

BACKGROUND: Human pulmonary dirofilariasis (HPD) is rare in Hungary, and it stems from Dirofilaria immitis, mainly transmitted through mosquito bites, with dogs as primary hosts. Despite its prevalence in veterinary settings, human cases are infrequent. Historically, Mediterranean countries report most HPD cases, but sporadic cases occur in temperate European regions. Radiologically, HPD often manifests in a non-specific manner, resembling pulmonary neoplasms, leading to unnecessary surgery and patient distress. METHODS: This study presents a notable case series from Hungary, encompassing a 12-year period, documenting 5 instances of HPD with the aim to provide baseline estimate of occurrence for future comparison. RESULTS: Among the patients studied, all were of middle age (median: 52 years, range: 37-69) and exhibited tumor-like lesions, primarily localized to the right lung, necessitating lobectomy or wedge resection. Histological examination consistently revealed a necrotizing granulomatous response characterized by remnants of helminths, without the presence of ovules. Furthermore, rigorous diagnostic procedures excluded other potential infectious agents through specialized staining techniques. Polymerase chain reaction analysis definitively confirmed the diagnosis of HPD in each case. CONCLUSIONS: This case series highlights HPD as a seldom zoonosis, with a probable escalation in its occurrence within temperate regions. Therefore, clinicians should maintain a heightened awareness of HPD in the differential diagnosis of pulmonary coin lesions. Early recognition and diagnosis are paramount for appropriate management and prevention of potential complications associated with this increasingly recognized infectious entity.

Microfilaruria of Dirofilaria immitis in a dog from Italy.

Dirofilaria immitis is a mosquito-borne nematode-causing canine heartworm disease, with adult worms localized in the pulmonary arteries and right heart. In rare cases, ectopic migration might occur, and adults and blood circulating microfilariae can be found in unusual organs or fluids (e.g., eyes, abdominal cavity, bone marrow, and urine). A 17-year-old mixed-breed female dog was presented in a private veterinary clinic in Italy for hematuria and dysuria. Physical examination showed cardiac mitral murmur with marked respiratory distress and cyanotic mucous membranes after handling. Abdominal ultrasounds revealed a non-specific chronic cystopathy, while the echocardiography showed enlargement of the right heart associated with tricuspid insufficiency and mitral regurgitation, with the presence of an adult filariae in the right ventricular chamber. Circulating microfilariae were observed in the blood smear and molecularly identified as D. immitis. Unusual microfilaruria was detected in the urine sediment. Data presented raise awareness about the occurrence of microfilariae in unusual locations, such as the bladder, suggesting the need of a thorough clinical and laboratory assessment where D. immitis is endemic.

Clinical Characteristics of Human Pulmonary Dirofilariasis in Japan: An Uncommon Differential Diagnosis of a Solitary Pulmonary Nodule.

Human pulmonary dirofilariasis (HPD) is a zoonotic disease caused by Dirofilaria immitis. Most HPD cases are asymptomatic and are either detected during annual health checkups or incidentally identified during the investigation of other diseases, particularly primary or metastatic pulmonary lung cancers. However, the frequency and clinical features of Japanese patients with HPD remain unclear. We analyzed data from the Japanese Medical Abstract Society database and identified 69 cases between 1978 and 2022. The incidence of HPD increased until the 2000s but declined markedly in the 2010s. The incidence is higher in the southwestern region and lower in the northeastern region of Japan. Health checkups are the primary diagnostic opportunities. The Chugoku and Shikoku regions have had high incidence rates per population. The diagnosis of HPD using a noninvasive procedure is typically difficult because of the absence of specific clinical symptoms, and approximately 70% of the cases are detected using video-assisted thoracoscopic surgery. Climate change may increase the incidence of HPD in the northeastern region of Japan, and travel to countries with poor vector control may be a risk factor for HPD transmission. Physicians should consider this parasitic infectious disease when examining patients presenting with solitary lung nodules.

A case of recurrent human Dirofilaria repens infection in Uzbekistan.

Dirofilaria repens is a zoonotic mosquito-borne filarioid that parasitizes in the subcutaneous tissues of carnivores, that has been incriminated in the great majority of human dirofilariasis cases reported throughout the Old World. From the Republic of Uzbekistan, recent data showed that this parasite is endemic in domestic and wild carnivores. In contrast, information regarding human infection is scarce and mostly outdated, with a single case report being published during the last decades. The present paper reports a case of recurrent autochthonous infection with D. repens in a patient living in the rural area of the Sirdaryo Region of Uzbekistan and having no international travel history. The first diagnosis was in 2019, when the patient presented with what was suspected to be a tumour of the left breast. Three years later, in 2022, she presented for a consultation after experiencing redness, occasional swelling and persistent itching in the umbilical region of the abdomen. The ultrasound indicated the presence of a living, motile nematode. Following anthelmintic therapy, the parasite was surgically removed and identified as a female D. repens. The present report highlights the possibility of human re-infection with D. repens and further underlines the necessity of raising public awareness and implementing of solid control strategies in carnivores.

Dirofilarial nodule as a differential diagnosis for subcutaneous lumps in children.

PURPOSE: Subcutaneous nodules in children are commonly caused by pilomatrixoma, dermoid cysts, soft tissue tumors, etc. Parasitic infections are reported to cause subcutaneous nodules and are infrequently described, mostly in the adult literature. We aim to describe the clinicopathological features of subcutaneous lumps caused by dirofilarial infestation in children in an endemic country. METHODS: A retrospective analysis was performed of all patients presenting with the above condition to Lady Ridgeway Hospital from 2018 to 2022 and their relevant details were captured in a proforma. RESULTS: There were 55 patients with a male to female ratio of 2:1. The mean age at presentation was 50 months (7-156 months). The mean duration was 97 days (1-820 days). The common sites involved were scrotum (30.9%), back (14.5%), abdominal wall (102.7%) and face (10.9%). The majority had a painless nodule (70.9%), while ten (18.2%) had features of acute inflammation. Thirty (55.5%) had preoperative ultrasonography which showed features of parasitic nodules in 26 (47.3%). Parasite was demonstrated in histopathological analysis only in 30 patients (54.5%). CONCLUSION: Dirofilarial nodule should be considered in the differential diagnosis of subcutaneous lumps in children, especially in the endemic areas.

First case of ocular dirofilariosis in Bulgaria caused by gravid female Dirofilaria repens.

Dirofilariosis caused by Dirofilaria (Nochtiella) repens is recorded sporadically among people in Europe, Asia and Africa. Still a worldwide controversy exist upon human parasite hosting. Herein, the first case of ocular dirofilariosis in Bulgaria caused by gravid female is presented. A single nematode was removed from the eye of the 76- year-old patient in the course of cataract surgery. Microscopic examination of the histological slides revealed microfilariae in the parasite's uterus, but not in the blood. Knott's method for detection of microfilariae in the peripheral blood was negative and the rest of laboratory blood and biochemical tests were within reference limits. A comprehensive review of the etiology, pathogenesis and clinical presentation of Dirofilaria repens infection is also highlighted.

Live Intraoral Dirofilaria repens of Lower Lip Mimicking Mucocele-First Reported Case from Croatia.

Dirofilariasis is an endemic infestation in tropical and subtropical countries caused by about 40 different species. It rarely occurs in the oral cavity and is mostly presented as mucosal and submucosal nodules. Differential diagnoses include lipoma, mucocele, and pleomorphic adenoma. We report a rare case of oral dirofilariasis mimicking mucocele in a 41-year-old male patient from Croatia without an epidemiological history of travelling outside the country. He came in because of non-painful lower lip swelling that had lasted for two months. The parasite was surgically removed from the lesion. This is the first reported case of oral dirofilariasis in Croatia. It is important to point out this rare diagnosis in order to make dentists aware of the possibility of the presence of such an infestation in common lesions of the oral mucosa.

New cases of human dirofilariosis on the Balkan Peninsula - "Masked intruders" uncovered by a surgeon.

Dirofilaria spp. nematodes are accidental parasites of humans causing mild to serious, superficial or visceral infections. Superficial dirofilariosis is rather common in Europe and is typically manifested as subcutaneous form. Herein we report 46 new cases of human dirofilariosis (19 patients with subcutaneous, 18 patients with ocular, 4 patients wih genital, 2 patients with submucosal, 2 patients with pulmonary and 1 patient with intramuscular form of infection) that were recorded from the beginning of 2015 to May 2021 on the Balkan Peninsula with a goal to update the prevalence of this parasitosis and point out potential problems in diagnosis and treatment. Besides, given the high possibility of misinterpretation as tumor, our second aim was to encourage the inclusion of this pathogen in the differential diagnosis of subcutaneous nodules. Although quite common forms, subcutaneous and ocular dirofilariosis can be very often misdiagnosed in clinical practice due to the absence of specific clinical manifestations. Therefore, raising awareness of clinicians about this zoonosis is needed as well as closer collaboration between physicians and veterinarians.

Human dirofilariosis in the 21st century: A scoping review of clinical cases reported in the literature.

Human dirofilariosis is a clinical entity caused by infection with nematode species of the genus Dirofilaria. The traditional picture depicts the disease as a sporadic event associated with the presence of a single immature worm causing a nodular lesion. With the aim to reassess this paradigm, establishing a more accurate picture of the disease and homogenize criteria, a scoping review was conducted by searching, screening and analysing published clinical cases of human dirofilariosis worldwide during the 21st century. After extracting data from 305 publications containing 576 case reports, results showed that human dirofilariosis is currently caused by five Dirofilaria species (mainly D. repens). Maturation was not uncommon, since 42.95% of the parasites recovered were described as mature worms, most of them females, 26.42% of which contained micofilariae in the uterus. Moreover, six microfilaremic cases have been described. The predominant clinical manifestation was the presence of a worm encapsulated within a nodule, but there is a considerable variety of accompanying symptoms depending on anatomical location and type of dirofilariosis. Parasites/nodules were found in 71 different anatomical locations, being the traditional nomenclature of human dirofilariosis unable to properly cover this complex situation. Delay in seeking medical assistance (patient perception) and the frequency of wrong clinical suspicions (doctor knowledge), strongly influenced clinical management. The initial suspicion in cases of subcutaneous and pulmonary dirofilariosis is predominantly a tumour, while in the ocular dirofilariosis a parasite (but not directly Dirofilaria) is mostly suspected. Surgery is usually applied, regardless of the use of non-invasive techniques during preoperative management and although its use is still limited, molecular approach is the most accurate technique to establish a species-level diagnosis. Accurate epidemiological, parasitological and clinical information while handling and reporting human clinical cases is a need for physicians and researchers to improve and standardize the clinical management of human dirofilariosis.

A rare clinical presentation of human Dirofilaria repens infection as a pseudo-tumour of the epididymis - Case Report.

Introduction. Epididymal dirofilariasis is one of the unusual manifestations of this zoonosis. In Slovakia, this is the third case out of 20 Dirofilaria repens infected patients in whom the worm (the parasite) was identified in the epididymis. The patient felt a painless tumour about 2 cm in size on the left testicle. During ultrasound examination, the radiologist observed a cyst containing a live worm within the epididymis. After mechanical stimulation, the movement characteristic for filarial worms (´filarial dance sign´) appeared. An orchiectomy was performed at the Department of Urology in the University Hospital in Kosice. Histopathology confirmed a parasitic cyst with a worm, and based on characteristic morphological features, the parasite was identified as Dirofilaria repens. Objective. The aim of case report is to alert physicians to the possibility dirofilarial infection of the epididymis, where tumors and cystic structures often occur and to present clinical signs of the disease.

Unusual feline Dirofilaria immitis infection: a case report.

Cats are less susceptible to Dirofilaria immitis infection than dogs. Although rare, the feline disease can be fatal even with low parasitic loads. The infection is often asymptomatic or has non-specific symptoms that are mainly associated with the death of immature worms. Microfilaremia is rare and transient. Normally, microfilaremia, when present, lasts for not more than 33 days. This study describes a feline case presenting with non-specific clinical signs and prolonged microfilaremia. Case: a random bred cat infected by feline leukemia virus (FeLV) that was found to be microfilaremic by chance. The infection was detected by the presence of microfilariae in a blood smear and was confirmed by antigen test (SNAP Feline Triple Test, Idexx®) and echocardiogram.

Pseudo-Tumor of the Epididymis, a Rare Clinical Presentation of Human Dirofilaria repens Infection: a Report of Autochthonous Case of Dirofilariasis in Southwestern Slovakia.

PURPOSE: Dirofilariasis caused by the filarial nematode Dirofilaria repens is mainly a disease of dogs and other carnivores. Also, humans can be accidentally infected with this parasite. The infective third-stage filariform larvae are transmitted by various species of mosquitoes. Until this day, a total of 17 human cases caused by D. repens have been diagnosed in Slovakia, 11 subcutaneous, 4 ocular, 1 pulmonary and 1 in the epididymis. The aim of this report was to describe an unusual clinical case of dirofilariasis of the scrotum. METHODS: Extirpated worm was subjected to the molecular and histological identification. PCR for the amplification of cytochrome oxidase subunit 1 (CO1) was performed using specific D. repens primer pair. RESULTS: Here we document the 13th case of human dirofilariasis in a 46-year-old man from southwestern Slovakia. Very rare in humans, genital involvement manifests itself as pseudotumor nodule affecting the epididymis. The patient consulted a general practitioner due to a palpable subcutaneous lump in the scrotum. Routine laboratory analysis revealed blood eosinophilia (16.6%). The ultrasound examination was indicated, and subsequently, surgical excision of the right epididymal nodule was performed. On the basis of histological microscopic examination and PCR-based detection, the helminth was identified as Dirofilaria repens. This represents the ninth case of autochthonous dirofilariasis in Slovakia. CONCLUSIONS: The majority of D. repens infections were recorded in southwestern regions of Slovak Republic, which are considered to be endemic areas for canine dirofilariasis. Our described patient also comes from southwestern part of Slovakia (Topolníky, Dunajská Streda region).

Unusual feline Dirofilaria immitis infection: a case report / Infecção incomum por Dirofilaria immitis em felino: relato de caso

Abstract Cats are less susceptible to Dirofilaria immitis infection than dogs. Although rare, the feline disease can be fatal even with low parasitic loads. The infection is often asymptomatic or has non-specific symptoms that are mainly associated with the death of immature worms. Microfilaremia is rare and transient. Normally, microfilaremia, when present, lasts for not more than 33 days. This study describes a feline case presenting with non-specific clinical signs and prolonged microfilaremia. Case: a random bred cat infected by feline leukemia virus (FeLV) that was found to be microfilaremic by chance. The infection was detected by the presence of microfilariae in a blood smear and was confirmed by antigen test (SNAP Feline Triple Test, Idexx®) and echocardiogram.

Resumo Gatos são menos susceptíveis à infecção por Dirofilaria immitis do que cães. Apesar de rara, a doença nos gatos pode ser fatal mesmo com baixas cargas parasitárias. Muitas vezes, a doença é assintomática ou apresenta sintomas inespecíficos, principalmente associados com a morte de formas parasitárias imaturas. Microfilaremia é rara e transitória. Normalmente, quando ocorre microfilaremia, ela permanece por, no máximo, 33 dias. Este estudo descreve o caso de um felino que apresentava sinais inespecíficos e microfilaremia prolongada: um gato sem raça definida, portador de infecção pelo vírus da leucemia felina (FeLV) que foi diagnosticado como microfilaremico ao acaso. A infecção foi detectada pela presença de microfilárias em esfregaço sanguíneo e, posteriormente, confirmada pelo teste de antígenos (SNAP Feline Triple Test, Idexx®) e por ecocardiograma.

Human case of subcutaneous nodule because of a novel genetic variation of Dirofilaria sp.

A 75-year-old man presented with a 1-cm large elastic soft subcutaneous nodule on the left side of the umbilicus, which when excised showed presence of a helminthic form within the granulomatous lesions. Morphologically, the helminth was considered to be of the genus Dirofilaria, and the patient showed increased serum antibody titer against canine filaria. The partial DNA sequence of the mitochondrial 12S rRNA gene locus of this clinical isolate showed the highest nucleotide identity (89.6%) with Dirofilaria repens; however, the phylogenetic analysis addressed the haplotype and Dirofilaria ursi as outgroups of the clusters of D. repens and Dirofilaria immitis, which are the causal agents of most human dirofilariasis. As like bear filaria D. ursi, a wide variety of other carnivore-parasitizing filaria species have rarely been reported in humans. The newly detected genetic haplotype in this case may correspond to one of these species of Dirofilaria, though the genetic references are not available thus far.

Rare cause of floaters: A motile live worm in vitreous cavity.

Ocular filariasis commonly presents as subconjunctival or eyelid nodules. We report a rare case of a live, motile worm causing floaters. The worm was isolated from the vitreous cavity and revealed to be Dirofilaria repens. Correct recognition of the worm is necessary as human dirofilariasis does not present as microfilaremia and does not require systemic therapy; in contrast to other causes of ocular filariasis, which require systemic therapy. As ophthalmologist may be the first physician to encounter such patients, a high index of suspicion is required for timely and adequate management.

Subconjunctival Dirofilariasis Presenting as Orbital Cellulitis.

Human ocular Dirofilariasis is a relatively rare, zoonotic disease, caused by a filarial nematode, Dirofilaria repens. This parasitic infestation usually presents as a subconjunctival nodule with hyperemia. The authors present a case of subconjunctival dirofilariasis in a 91-year-old gentleman, who presented with manifestations of orbital cellulitis. The live worm was surgically removed and identified to be D. repens.

The Diversity of Human Dirofilariasis in Western Sri Lanka.

BACKGROUND: Human dirofilariasis is an emerging zoonosis in many countries. Dirofilariasis caused by Dirofilaria repens may present with diverse clinical manifestations in humans due to aberrant localization of worm lesions causing diagnostic dilemmas. The aim of this retrospective study was to describe and update the demography and clinical spectrum of human dirofilariasis in western Sri Lanka. Nematode or nematode fragments isolated from excision biopsies that were confirmed as D. repens at the Department of Parasitology, Faculty of Medicine, University of Kelaniya, Sri Lanka, between 2012 and 2018 were included. Data on age, gender, and clinical details were obtained from case files. Identity of worms was established by morphometry and cuticle characteristics on wet-mount preparation. Specimens from unusual case presentations were further analyzed by PCR with specific primers for internal transcribed spacer region 2 (ITS2) of the ribosomal DNA. RESULTS: Sixteen nematode specimens isolated from subconjunctiva (n=2), subcutaneous (n=13) and intramuscular (n=1) locations were identified as D. repens by morphometry (average length 11.5 cm) and the characteristic longitudinal striations on cuticle visualized by microscopy. The age distribution of cases ranged from 1 to 65 years with a mean of 21.5. Females were more frequently affected (n=10, 62.5%) and worm locations were commonest in the orbital region (5/16) and scrotum (3/16). Imaging techniques were of use in detecting infections in deeper tissue levels. PCR analysis of DNA extracted from a worm in an intramuscular granuloma of the temporal region elicited the expected band at 484bp for D. repens. CONCLUSIONS: Human dirofilariasis is on an upward trend in incidence. Imaging techniques were of use in clinical diagnosis and molecular speciation in establishing the species identity in unusual case presentations. We suggest a more conservative approach in the management of human dirofilariasis and recommend a one health approach for control.

Encapsulated living worms due to periorbital dirofilariasis: detection with high-resolution sonography.

Sonography (US) is commonly required when a superficial lump appears. We present the case of a patient for whom US was highly suggestive of living worms causing a recurrent periorbital mass. After surgery, the final diagnosis was a nodule composed of dirofilariasis larva.