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.

Detection and dynamics of tumor necrosis factor alpha in the diagnosis and treatment of canine heartworm disease.

The aim of this study was to determine the concentration of TNF-alpha (TNF-α) in dogs naturally infected with Dirofilaria immitis (D. immitis) and to assess whether there are any changes in TNF-α concentration and their dependence during therapy for heartworm disease (HWD). For this study, 14 client-owned dogs with HWD were selected. Clinical and parasitological examinations (modified Knott test for circulating microfilariae and SNAP Test IDEXX for circulating D. immitis antigen) had been used for diagnosing D. immitis and HWD. All dogs were treated with an alternative therapy for HWD (oral doxycycline 10 mg/kg b.w., once daily for 6 weeks, then alternately 4 weeks without and 2 weeks with the medication, and oral ivermectin 6-14 µg/kg b.w., every 2 weeks). The dogs blood sera at the moment of HWD diagnosis, during and at the end of therapy were frozen for further quantifying of TNF-α (Canine TNF-alpha ELISA kit, Thermo scientific). At the moment of HWD diagnosis TNF-α was detected in 9 dogs (7.21±12.44 pg/ml). Concentration of TNF-α was not significantly change during the therapy, neither related to the level of D. immitis antigen nor to antigen level changes. The alternative therapy for HWD has no influence on TNF-α concentration dynamics.

Evaluation of coagulation and platelet activation state and function in heartworm-infected dogs.

BACKGROUND: Enhanced platelet responses have been demonstrated in heartworm-infected (HWI) dogs; however, the cause and clinical implications of altered platelet function have not been fully elucidated. OBJECTIVE: This study evaluated platelet function in HWI dogs. METHODS: Anticoagulated whole blood collected from eight HWI and eight uninfected dogs was evaluated using turbidometric platelet aggregometry, a platelet function analyzer (PFA-100), a total thrombus analysis system (T-TAS), tissue factor-activated and tissue plasminogen activator modified thromboelastography (TF- and tPA-TEG), CBC, von Willebrand Factor activity, and fibrinogen concentrations. Platelet activation state and the presence of reticulated platelets were assessed via flow cytometric expression of P-selection (CD-62P) and thiazole orange staining. RESULTS: Platelet aggregation responses to adenosine diphosphate (ADP, 10 µM) or collagen (20 µg/mL), PFA-100 closure times, and T-TAS occlusion times did not differ between groups. TEG values TF-R, tPA-R, TF-K, and TF-LY60 were decreased (P = .025, P = .047, P = .038, P = .025) and TF-MA, tPA-MA, TF-G, tPA-G and TF-alpha angle were increased (P < .04) in HWI dogs. HWI dogs had higher fibrinogen concentrations (465.6 ± 161 mg/dL vs 284.5 ± 38 mg/dL, P = .008) and eosinophil counts (0.686 ± 0.27 × 103/µL vs 0.267 ± 0.20 × 103/µL, P = .003). There was no difference in hematocrit, activation state, or percent of reticulated platelets. Non-activated reticulated platelets exhibited higher CD62P expression compared with mature platelets. CONCLUSIONS: Chronic canine heartworm disease was accompanied by hypercoagulability, hyperfibrinogenemia, and decreased fibrinolysis. Enhanced platelet activation was not identified in this group of HWI dogs.

Subconjunctival Dirofilaria masquerading as nodular scleritis.

A man in his late 50s presented with a gradually enlarging, painless, reddish mass on the white portion of his left eye for 2 weeks. His best-corrected visual acuity was 20/20 in both eyes. Slit-lamp examination showed a congested, nodular, elevated lesion on the temporal bulbar conjunctiva with two pustule-like elevations. Anterior segment optical coherence tomography showed a subconjunctival solid mass rather than an abscess or a cyst. Scleral deroofing was performed and a long thread-like object resembling a dead worm was identified. The worm was removed intact, and its histopathology confirmed the diagnosis of Dirofilaria Peripheral blood smear did not show any microfilariae. No recurrences or new lesions were observed during the follow-up examinations at 1 and 5 months post-surgery. This case highlights the importance of considering a parasitic aetiology in cases of nodular or infectious scleritis.

Can nematode infection cause internal bleeding in dogs? A case of Dirofilaria immitis infection in cavitary fluids.

A 9-year-old dog was presented with weight loss, respiratory effort, and an enlarged abdomen. Imaging studies and exploratory surgery showed pulmonary and splenic masses and bi-cavitary effusion, later classified as hemorrhage. Cytology of the peritoneal and pleural fluids also revealed several microfilariae. Immunologic and molecular analyses confirmed Dirofilaria immitis infection and histopathology of the spleen indicated a cavernous endothelial proliferation with undefined etiology (hemangiosarcoma vs reaction to parasite infestation). The nematode larvae are speculated to have entered body cavities via erratic migration or via hemorrhage and visceral lesions to be related to parasitism. Nematode infection should be considered as a differential diagnosis for internal bleeding of undetermined origin.

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.

Prevention of heartworm infection in dogs using a combination of moxidectin, imidacloprid and praziquantel: evidence from a randomized clinical trial.

The aim of this study was to evaluate the efficacy of a topical combination of moxidectin 3.5%, imidacloprid 10% and praziquantel 10% for the prevention of Dirofilaria immitis (Leidy, 1856) infection in dogs. For this purpose, a randomized and controlled clinical trial was conducted between August 2021 and October 2022, in the municipality of Goiana, state of Pernambuco, north-eastern Brazil, where heartworm is highly prevalent. Of the 213 dogs initially sampled (baseline), 68 (31.9%) were positive for adult antigens (SNAP 4Dx Plus, Idexx) and/or microfilariae (modified Knott's test). On day 0, 140 negative dogs were randomly included in the treatment and control groups, 70 animals each. During the study, 60 dogs (34 treated and 26 untreated) were removed for different reasons. At the end of the study (day 360 ± 2), 36 treated and 44 untreated were sampled and included in the efficacy calculation. The efficacy against the development of adults and microfilariae was 84.7%, with only one treated dog being positive for adult antigens but negative for microfilariae. On the other hand, eight untreated dogs were positive for adult antigens and/or microfilariae, resulting in a significant difference in the number of positives between groups (Chi-square test = 4.706, df = 1, P = 0.0301). Remarkably, the efficacy against the appearance of D. immitis microfilariae was 100% (i.e., all treated dogs negative) and three untreated dogs were positive for microfilariae. The topical combination of moxidectin 3.5%, imidacloprid 10% and praziquantel 10% significantly reduced the risk of D. immitis infection in treated dogs as compared with untreated dogs, in a highly endemic area in north-eastern Brazil.

Subcutaneous dirofilariasis in a 25-year-old male patient in Belgium on ultrasonography: a case report.

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. CASE PRESENTATION: 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. CONCLUSION: 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.

Spontaneous pneumothorax in a dog with a history of successfully treated heartworm disease: A case report.

OBJECTIVE: To describe a dog presented with spontaneous pneumothorax secondary to chronic pulmonary changes associated with a history of resolved canine heartworm disease. CASE OR SERIES SUMMARY: A 7-year-old 25.2kg female spayed German Shepherd mix was presented for management of spontaneous pneumothorax. The dog had a history of heartworm disease that underwent therapy prior to adoption, and the dog was heartworm antigen negative (SNAP 4Dx) during hospitalization for the pneumothorax. An exploratory thoracotomy was performed due to an unresolving pneumothorax requiring multiple thoracocenteses. Perioperatively, the lungs did not expand with positive pressure ventilation and diffuse, multifocal to coalescing areas of darkened tissue that were grossly consistent with necrosis and/or hemorrhage were noted. The dog was euthanized intraoperatively due to an assumed poor prognosis. Histopathologic examination findings were consistent with chronic reactive changes related to previous heartworm infection. No neoplastic or infectious etiologies were identified. NEW OR UNIQUE INFORMATION PROVIDED: Spontaneous pneumothorax is a known complication of active heartworm infection. However, this case represents the first report of spontaneous pneumothorax secondary to chronic pulmonary changes caused by resolved heartworm infection.

[A case of pleuropulmonary dirofilariasis caused by Dirofilaria repens. Case report].

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.

Diagnostic Accuracy of a Point-of-Care Immunoassay for Feline Immunodeficiency Virus Antibodies, Feline Leukemia Virus Antigen, and Dirofilaria immitis Antigen.

Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are retroviral infections of cats worldwide whose clinical manifestations range from mild to severe disease. In both cases, infected cats can live a long life with proper care and should be managed to prevent infection of other cats. Dirofilaria immitis, the nematode that causes heartworm disease, can infect cats in any region where dogs are infected. Though cats are more resistant to infection, clinical diseases in the form of heartworm-associated respiratory disease can cause death. Screening for these infectious diseases enables veterinarians to manage their cases and prevent the spread to other cats. We describe the diagnostic accuracy of a point-of-care immunoassay for FIV, FeLV, and heartworm, compared to reference methods commonly available through reference laboratories to the practicing veterinarian. For FIV, we report 100% sensitivity (95% confidence limits (CL): 96.2-100%) and 97.8% specificity (95% CL: 95.4-99.4%). For FeLV, we report 100% sensitivity (95% CL: 97.7-100%) and 99.2% specificity (95% CL: 97.1-99.9%). And for heartworm, we report 90.2% sensitivity (95% CL: 76.9-97.3%) and 100% specificity (95% CL: 98.3-100%). Veterinarians may expect this performance relative to the reference methods they use for confirmatory serological testing.

Dirofilariosis infestation of pectoralis major muscle in Italy, a case report.

Abstract: Zoonotic dirofilariasis infestation, caused by Dirofilaria Repens, is described worldwide in different countries. A 31-years-old male patient presented thoracic muscle pain after growth of an ovoidal undefine cyst in left parasternal region. Patient reported several contacts with different species of animals for a familiar activity. In absence of blood inflammatory indices and systemic symptoms, imaging studies showed a suspected muscle cyst infection. Surgical excision was performed and microbiology confirmed parasite nature. Dirofilaria Repens, probably adult female, was identified. Treatment resulted to be definitive and any other clinical and surgical approach was needed. Healing time was uneventful and follow-up showed no further systemic relapses. The case highlights the effectiveness of surgical treatment in this subcutaneous infestation for an increasing number of human cases reported in endemic areas such as Central Italy.

Unusual cause of unilateral facial oedema: intramuscular dirofilariasis.

INTRODUCTION: Unilateral facial oedema may occur due to inflammatory, infective, or cystic pathology; patients often seek medical help at an early stage. CASE REPORT: We report one such case caused mimicking a parotid abscess, caused by dirofilariasis. CONCLUSION: Dirofilariasis is an emerging zoonosis and should be considered a differential diagnosis of atypical facial swelling. It is equally important for clinicians, radiologists, and pathologists to be familiar with the diagnostic characteristics to avoid misdiagnosis.

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.

Albuminuria and proteinuria in dogs infected with Dirofilaria repens: A cross-sectional study.

BACKGROUND: It is unknown whether Dirofilaria repens is capable of causing similar glomerular lesions, as does Dirofilaria immitis. OBJECTIVE: To determine whether D. repens infection could cause albuminuria or proteinuria. ANIMALS: Sixty-five clinically healthy laboratory beagle dogs. METHODS: In this cross-sectional study, dogs were tested for D. repens infection (modified Knott test, PCR test, D. immitis antigen test) and were grouped as "D. repens infected" or "control" dogs. Urinary albumin-to-creatinine ratio (UAC) and urinary protein-to-creatinine ratio (UPC) were measured from samples taken by cystocentesis. RESULTS: Forty-three (26 infected, 17 control) dogs were included in the final study group. UAC but not UPC level was significantly higher in the infected group (UAC median 12.5; range, 0-700 mg/g and UPC median 0.15; range, 0.06-1.06) than in the control group (UAC median 6.3; range, 0-28 mg/g and UPC median 0.13; range, 0.05-0.64; P = .02 and P = .65). Overt proteinuria (UPC > 0.5) was present in 6/26 (23%) of the infected dogs and 1/17 (6%) of the control dogs. Albuminuria (UAC > 19 mg/g) was detected in 9/26 (35%) dogs in the infected group, and 2/17 dogs (12%) in the control group. CONCLUSIONS AND CLINICAL IMPORTANCE: D. repens might cause similar glomerular lesions to those caused by D. immitis.

Involvement of the excretory/secretory and surface-associated antigens of Dirofilaria immitis adult worms in the angiogenic response in an in-vitro endothelial cell model.

Angiogenesis is a process by which new vessels are formed from pre-existing ones when the physiological conditions of the vascular endothelium are altered. Heartworm disease, caused by Dirofilaria immitis, causes changes in the vascular endothelium of the pulmonary arteries due to obstruction, friction, and hypoxia. The aim of this study was to analyze whether the excretory/secretory and surface-associated antigens of adult worms interact and modulates the angiogenic mechanism, viable cell number and cell migration, as well as the formation of pseudo-capillaries. Cultures of human vascular endothelial cells (HUVECs) stimulated with excretory/secretory antigens (DiES), surface-associated antigens (Cut) from D. immitis adult worms, VEFG-A (Vascular Endothelial Growth Factor A), as well as DiES+VEFG-A and Cut+VEFG-A were used. The production of VEFG-A and other proangiogenic [soluble VEFGR-2 (sVEFGR-2), membrane Endoglin (mEndoglin)] and antiangiogenic [VEFGR-1/soluble Flt (sFlt), soluble Endoglin (sEndoglin)] molecules was assessed using commercial ELISA kits. Cell viability was analyzed by live cell count and cytotoxicity assays by a commercial kit. In addition, viable cell number by MTT-based assay, cell migration by wound-healing assay carrying out scratched wounds, and the capacity of pseudo-capillary formation to analyze cell connections and cell groups in Matrigel cell cultures, were evaluated. In all cases, non­stimulated cultures were used as controls. DiES+VEFG-A and Cut+VEFG-A significantly increased the production of VEFG-A and sVEFGR-2, and only Cut+VEFG-A significantly increased the production of VEFGR-1/sFlt compared to other groups and non-stimulated cultures. Moreover, only DiES+VEFG-A produced a significant increase in viable cell number and significant decrease cell migration, as well as in the organization and number of cell connections. Excretory/secretory and surface-associated antigens of adult D. immitis activated the angiogenic mechanism by mainly stimulating the synthesis of proangiogenic factors, and only excretory/secretory antigens increased viable cell number, activated cell migration and the formation of pseudo-capillaries. These processes could lead to vascular endothelial remodeling of the infected host and favor the long-term survival of the parasite.