BACKGROUND: We present an extremely rare manifestation of dirofilariasis in the pleural cavity. This is the first human pulmonary dirofilariasis reported in Lithuania; according to our knowledge, only two other patients were documented with this pathology in the world.
METHODS: A 72-year-old woman was admitted to the hospital complaining of dyspnea, left-side chest pain, and a dry cough. She was a retiree living alone in the countryside without domestic pets (sometimes stray dogs appear) or a travel history. A complete blood count was within normal limits, with a CRP level of 16.8 mg/l and D-dimer concentration of 900 µg/l, which raised suspicion of pulmonary embolism. In chest computed tomography angiography, pulmonary embolism was excluded, and only left pleural effusion without abnormal lesions was confirmed. Left thoracocentesis was performed, and the pleural fluid was evaluated as an exudate with a predominance of eosinophils (59%), along with the presence of parasites. These parasites exhibited the morphology of Dirofilaria repens. Oral doxycycline (100 mg, twice daily) and albendazole (400 mg, twice daily) were prescribed for a 14-day course. A month later, there were no pathological findings on the chest X-ray, and the patient no longer had respiratory symptoms. However, the patient presented with an emerged, painful palpable right breastmass, where the rash was previously observed. Ultrasound imaging revealed a 1.5 × 2 cm nodule, which was surgically removed. Parasites consistent with Dirofilaria repens were suspected but not definitively identified. Pharmacological treatment for dirofilariasis was not further prescribed.
CONCLUSIONS: This case encourages doctors to be more vigilant because the patient, who neither travelled nor kept any pets, contracted dirofilariasis. Diagnostic and treatment guidelines are lacking, necessitating further research. Treatment with doxycycline and albendazole yielded positive outcomes, suggesting potential efficacy for dirofilarial pleuritis.

Dirofilariasis is an infection caused by the filarial nematode Dirofilaria. Dirofilaria immitis primarily causes pulmonary dirofilariasis, while subcutaneous dirofilariasis is usually caused by Dirofilaria tenuis and Dirofilaria repens but can rarely be caused by Dirofilaria immitis as well. Here we report a rare case where in a 26-year-old with a history of international travel presented with swelling over the nasal dorsum. Following surgical excision, histopathological examination revealed dirofilariasis. Although uncommon, this zoonosis should be taken into consideration as a differential diagnosis of facial swellings.

Subcutaneous dirofilariasis, caused by the parasitic nematode Dirofilaria repens, is a growing concern in Europe, affecting both dogs and humans. This study focused on D. repens Dr20/22, a protein encoded by an alt (abundant larval transcript) gene family. While well-documented in L3 larvae of other filariae species, this gene family had not been explored in dirofilariasis. The research involved cloning Dr20/22 cDNA, molecular characterization, and evaluating its potential application in the diagnosis of dirofilariasis. Although Real-Time analysis revealed mRNA expression in both adult worms and microfilariae, the native protein remained undetected in lysates from both developmental stages. This suggests the protein\'s specificity for L3 larvae and may be related to a process called SLTS (spliced leader trans-splicing), contributing to stage-specific gene expression. The specificity of the antigen for invasive larvae positions it as a promising early marker for dirofilariasis. However, ELISA tests using sera from infected and uninfected dogs indicated limited diagnostic utility. While further research is required, our findings contribute to a deeper understanding of the molecular and immunological aspects of host-parasite interactions and could offer insights into the parasite\'s strategies for evading the immune system.

Dirofilariasis is an infectious disease caused by species of the Dirofilaria genus. It is manifested by the appearance of a subcutaneous swelling, especially in the eye region. We present the case of a 29-year-old patient who presented with facial asymmetry in the right genian region. Following clinical and paraclinical evaluations, the diagnosis of a parasitic cyst was established in the context of dirofilariasis with Dirofilaria repens (D. repens). Treatment consisted of surgical excision of the formation associated with prophylactic antibiotic medication. Macroscopic analysis of the excision piece revealed a structure that contained a cystic cavity and a filamentous form with a length of approximately 10 mm and a diameter of 1 mm. This is the first case of dirofilariasis located in the genian region reported in Romania. The overview of this pathology is important to raise awareness among physicians about its presence and clinical variations. Understanding such cases helps healthcare professionals enhance diagnostic skills, refine treatment strategies, and provide valuable insights into the prevalence and clinical presentation, fostering early detection and timely intervention. Detailed case reports contribute to the understanding of the disease\'s epidemiology, including risk factors and transmission patterns, which is essential for effective public health strategies.

BACKGROUND: Dirofilariasis is a vector-borne disease caused by parasitic nematodes of the genus Dirofilaria spp., considered an emerging concern in both veterinary and human medicine. Climate changes and human activities, such as pet travel, contribute to the spread of diseases to new non-endemic regions. Poland is dominated by subcutaneous dirofilariasis caused by D. repens infections. Cardiopulmonary dirofilariasis, also known as a heartworm disease is much more rare with only single autochthonous cases reported so far. Also, imported infections are observed sporadically in dogs traveling to endemic countries. In this study, we report the first case of a dog in Poland, never having traveled abroad, co-infected with Dirofilaria repens and Dirofilaria immitis.
METHODS: A 14-year-old mixed breed, an intact male dog with fever, lightly pale mucosal membranes, moderate abdominal pain, and a mild cough was presented in a veterinary clinic in Warsaw, Poland. The examination of the blood sample collected for complete morphology and biochemistry revealed the presence of live microfilariae. Presence of the DNA of both microfilariae species was detected using Real-Time PCR with species-specific primers.
CONCLUSIONS: Since the remaining diagnostic methods like Knott\'s test, antigen test or echocardiography did not reveal the presence of D. immitis, we discussed the impact of microfilariae periodicity and low worm burden infections on the limited efficiency of these techniques. We strongly recommend using a mixed diagnostic approach for the most sensitive and specific diagnosis since the ideal diagnostic method does not exist, and several factors may contribute to misdiagnosis. Furthermore, we considered factors that contribute to the uncontrolled spread of dirofilariasis such as climate changes, introduction of new species of mosquitoes competent for the transmission of the disease, and wildlife animals as an important reservoir of this parasitosis. Given that Poland shares borders with countries classified as endemic and pre-endemic for D. immitis, such as Slovakia and Ukraine, it is reasonable to anticipate a rise in autochthonous heartworm infections and shifts in the epidemiological pattern of dirofilariasis in the coming years.

Dirofilaria immitis is a ubiquitous nematode parasite with zoonotic potential, transmitted by mosquitoes, that causes heartworm disease in various animal species. Dogs are the parasite\'s typical final host, and wild carnivores represent the parasite\'s reservoir in nature. Studies on D. immitis infections in wild animals are essential to assess infection pressure for domestic animals, and until now, there has been only one infection case reported in a European badger (Meles meles). The current report describes the first two European badger cases with cardiovascular dirofilariosis in Greece. Two adult male badgers were rescued in Heraklion and Chania, Crete Island, and admitted to \"ANIMA -Wildlife Rehabilitation Centre\" in Athens. The detailed clinical examination revealed that the first badger suffered from severe broncho-pneumonitis while the second one displayed clinical signs associated with severe brain trauma. Blood samples were taken for haematology and biochemistry analyses during their short hospitalisation period. In addition, different routine diagnostic tests were carried out, including heartworm antigen testing (ELISA) and the modified Knott\'s test for microfilariae. Both badgers were positive in both tests. The animals died a few hours after their admission and the detailed necropsies followed, revealed the presence of three parasites in each animal\'s right heart, morphologically identified as adults of D. immitis. These findings add the European badger in the list of additional potential reservoir hosts for D. immitis and highlight the potential role of wildlife for companion animals and human health.

Dirofilaria spp. are vector-borne filarial nematodes that affect a variety of animal species, including humans. Dirofilaria immitis and Dirofilaria repens are the two main zoonotic species, but also other wildlife-associated Dirofilaria species are occasionally reported as causative agents of human dirofilariasis, including Dirofilaria striata, Dirofilaria tenuis, Dirofilaria ursi, Dirofilaria spectans, and Dirofilaria magnilarvata. Since the etiological identity of most of the species mentioned here is arguable, we summarized and critically discussed data concerning infections in humans, focusing on the reliability of Dirofilaria species identification. We advocate the importance of combined morphological and genomic approaches to provide unequivocal evidence for their zoonotic potential and pathogenicity.

BACKGROUND: Subcutaneous dirofilariasis is a parasitic zoonosis commonly described in Canidae but rarely seen in humans. Most physicians are unfamiliar with this disease, especially in nonendemic areas, which can lead to medication error and diagnostic and treatment delay. To the best of our knowledge, no previous case of subcutaneous dirofilariasis preoperatively diagnosed on ultrasound has been described in Western Europe.
METHODS: A 25-year-old Belgian male patient presented with a subcutaneous nodule in the epigastric region. Ultrasound investigation showed a typical cystic lesion with an internal serpiginous structure with echogenic lines, and there was active twirling movement of this serpentine structure during investigation, pathognomonic for subcutaneous dirofilariasis. Surgical extirpation was performed, and the diagnosis was histopathologically confirmed.
CONCLUSIONS: Subcutaneous dirofilariasis has a characteristic appearance on ultrasound but is not well known in nonendemic areas, often leading to diagnostic delay and initial incorrect treatment. More knowledge of this disease and of its characteristic ultrasound appearance will hopefully lead to better patient care.

The differential diagnosis of neoplasms of various localizations is the primary task in clinical practice of all physicians. We present a description of the case of invasion with Dirofilaria repens in the lung of a 68-year-old patient. In 2016 the patient was diagnosed with cancer of the left kidney and underwent a left-sided nephrectomy. During the dynamic observation in 2019, a lump was found in the left lung, which was regarded as a metastasis. An atypical SIX resection of the left lung was performed. Microscopy of the removed lump revealed the presence of a nematode of the genus Dirofilaria, presumably D. repens. The species identity of D. repens was confirmed by polymerase chain reaction using species-specific primers. It is known that the morphological identification of parasites up to the species in the surgical material presents certain difficulties and requires high professional training of the researcher. Therefore, the diagnosis of dirofilariasis in atypical localizations of nematodes in the human body is of great importance in the differentiation of malignant and benign formations, and the use of the polymerase chain reaction method can significantly increase the accuracy in establishing the final diagnosis.
В клинической практике дифференциальная диагностика новообразований различной локализации является первостепенной задачей врачей всех специальностей. В настоящем исследовании представлено описание случая паразитирования в легком Dirofilaria repens. В 2016 г. у пациента диагностирован рак левой почки и выполнена левосторонняя нефрэктомия. При динамическом наблюдении в 2019 г. в левом легком обнаружен метастаз. Выполнена резекция легкого. В удаленном образовании обнаружена нематода рода Dirofilaria. Методом полимеразной цепной реакции установлен вид паразита – D. repens. Морфологическая идентификация гельминтов в операционном материале часто представляет определенные трудности и требует высокой профессиональной подготовки специалиста; использование метода полимеразной цепной реакции позволяет точно определить видовую принадлежность паразита.

Dirofilaria repens is a paradigmatic example of an emerging vector-borne pathogen (VBP) in both human and veterinary fields. The spatial expansion and the increasing zoonotic impact of this VBP can be related to several drivers including the genetic structure of parasite populations. Italy is one of the European countries traditionally endemic with the highest incidence of canine and human cases of subcutaneous dirofilariosis. The present study aimed to assess the genetic identity and variability of D. repens isolates of human and canine origin from areas of Central Italy, compared with those isolated from different areas of Europe by sequence analysis of mtDNA genes (i.e., 12 S rDNA and cox1). A total of twenty isolates of D. repens were obtained from biopsies of subcutaneous and ocular cases of dirofilariosis occurring in 10 dogs and 10 humans. The sequence analysis of 12 S rDNA showed that all the sequences obtained clustered as a monophyletic group with a strong nodal support, indicating that all sequence types represented D. repens. The cox1 and the 12 S sequence analysis did not show host-related polymorphisms between human and dog-derived specimens. The sequence analysis of cox1 was performed including 8 additional sequences previously obtained from human and canine isolates in the same areas. Out of the 28 sequences analyzed, 20 were grouped in a haplogroup comprising 15 haplotypes (i.e., DR1, DR2, DR4, DR5, DR7, DR8, DR10-DR18), 2 sequences matched to DR9, reported for the first time in Italy, and 6 showed peculiar polymorphisms that were not previously described. The results obtained have implications for a better understanding of the epidemiology and phylogeography of this emerging vector-borne zoonotic parasite.