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.

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.

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.

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.

Management and outcome of intracardiac heartworms in dogs.

BACKGROUND: Intracardiac heartworm (IH) disease is a serious condition that can become life threatening if the patient develops caval syndrome. We aim to describe the management and outcome of IH in dogs evaluated by Medvet's New Orleans cardiology service from November 2015 to December 2021. METHODS: Records of 27 dogs with IH were examined retrospectively. Follow-up information was obtained from phone conversations with referring veterinarians and owners. RESULTS: Nine of 27 dogs had a previous diagnosis of heartworm disease and were undergoing "slow kill" treatment; 12/27 dogs' heartworm disease was a new diagnosis, and 6/27 had either scheduled or started adulticide therapy. Nine dogs had heartworm extraction. No dogs died during the heartworm extraction procedure. Four of 9 dogs have died (survival time 1; 676; 1815 and 2184 days). One dog died the day after the procedure secondary to continued respiratory distress; the other three died of non-cardiac causes. Five of nine are alive (median follow-up 1062 (range 648-1831) days. Eleven dogs had IH resolution. In 7/11 this occurred while undergoing stabilization for heartworm extraction. In 4/11 heartworm extraction was not recommended because of low IH burden. All dogs with IH resolution were discharged from the hospital. Four of 11 have died (survival time 6; 22, 58 and 835 days), and 6/11 are alive (median follow-up 523 (range 268-2081) days. One was lost to follow-up after 18 days. Five dogs were medically managed. In one of five dogs, extraction was not recommended because of low IH burden. In four of five extraction was recommended but declined. One of five has died (survival 26 days), and four of five are alive (follow-up 155, 371, 935 and 947 days). Two dogs were killed at the time of diagnosis. Fifteen of 27 dogs were considered to have caval syndrome. CONCLUSION: The results suggest that patients with IH resolution have a good long-term prognosis. Most often IH resolution occurred while the dog was undergoing stabilization for heartworm extraction. When IHs are present, heartworm extraction should still be considered the treatment of choice and recommended as first-line therapy whenever possible.

A case of inguinal hernia associated with atypical Dirofilaria repens infection in a dog.

BACKGROUND: Dirofilaria repens is a filarioid nematode transmitted by mosquitoes. Adult D. repens are typically localized in the subcutaneous tissue of the host, but other, atypical localizations have also been reported. There have been several reports of clinical cases involving an association of parasites and hernias in both animals and humans. However, it is unclear if parasitic infection can act as a triggering factor in the development of hernias. METHODS: A 12-year-old dog was referred to a private veterinarian clinic in Satu Mare, northwestern Romania due to the presence of a swelling in the lateral side of the penis (inguinal area). The dog underwent hernia repair surgery during which four long nematodes were detected in the peritoneal serosa of the inguinal hernial sac. One female specimen was subjected to genomic DNA extraction to confirm species identification, based on amplification and sequencing of a 670-bp fragment of the cytochrome c oxidase subunit 1 (cox1) gene. Treatment with a single dose of imidacloprid 10% + moxidectin 2.5% (Advocate, Bayer AG) was administered. RESULTS: The nematodes were morphologically identified as adult D. repens, and the BLAST analyses revealed a 100% nucleotide similarity to a D. repens sequence isolated from a human case in Czech Republic. CONCLUSIONS: We report a case of an atypical localization of D. repens in the peritoneal cavity of a naturally infected pet dog with inguinal hernia and discuss the associations between hernia and parasitic infections.

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.

Angiogenesis in cardiopulmonary dirofilariosis: does the Wolbachia surface protein have a pro- or anti-angiogenic effect?

Cardiopulmonary dirofilariosis caused by Dirofilaria immitis produces inflammation, blood vessel obstruction and hypoxia, which are required conditions for the beginning of the process of neovascularization. Since D. immitis harbours intracellular symbiotic Wolbachia bacterium, the global understanding of the angiogenic process requires the analysis of the effect of the parasite molecules, but also that of Wolbachia. Canine primary lung microvascular endothelial cells were treated with the recombinant Wolbachia surface protein (rWSP) and the expression of angiogenic factors like Vascular Endothelial Growth Factor-A (VEGF-A), sFlt, membrane Endoglin (mEndoglin) and soluble Endoglin (sEndoglin), as well as the in vitro formation of pseudocapillaries, were measured. The analyses showed a significant increase in the expression of pro-angiogenic VEGF-A and anti-angiogenic sEndoglin, together with a significant decrease in both pro-angiogenic mEndoglin and pseudocapillary formation, compared to untreated controls. Due to the complexity of the angiogenic process and its relationship with other physiological processes like inflammation and fibrinolysis, these results might suggest that rWSP participate in various mechanisms related to each other and its effects might depend either on the balance between them or on the moment of their occurrence.

Treatment of dogs with severe heartworm disease.

Fortunately, the majority of dogs diagnosed with heartworm infection are asymptomatic (or have only mild symptoms such as intermittent cough) and go through adulticide therapy without complication. Complications occurring with heartworm infection and during its treatment most often directly reflect the pulmonary vascular and parenchymal injury inflicted by Dirofilaria immitis. Clinical signs may include exercise intolerance, frequent cough, hemoptysis, tachypnea, and dyspnea. Severe manifestations such as heart failure and caval syndrome may prove fatal. Acute hypersensitivity reactions after initiation of macrocyclic lactone preventive therapy in microfilaremic dogs or after melarsomine injection during adulticide therapy do occur, but are uncommon. This article reviews complications associated with heartworm infection.

Resolution of caval syndrome during initial hemodynamic stabilization in dogs with heartworm disease.

OBJECTIVE: To report on the spontaneous resolution of caval syndrome in 5 dogs selected for their response to medical stabilization prior to scheduled heartworm extraction. SERIES SUMMARY: Five dogs with heartworm caval syndrome were treated with sildenafil, fluid, and supplemental oxygen therapy. Moreover, 4 of 5 dogs were also administered pimobendan to achieve hemodynamic stabilization in preparation for percutaneous heartworm extraction. Spontaneous heartworm migration back into the pulmonary arteries was detected from 2 h to 5 days after treatment initiation. UNIQUE INFORMATION PROVIDED: Unanticipated spontaneous resolution of caval syndrome was documented in a low number of dogs after initiation of a patient stabilization protocol aiming at improving right ventricular hemodynamics and reducing pulmonary artery pressure prior to scheduled heartworm extraction. At this time, it is unknown if intervention to improve the hemodynamic status of the animal prior to heartworm extraction improves procedure outcome, and which factors contributed to the migration of the heartworms back into the pulmonary arteries in these selected cases. Therefore, this approach cannot be recommended in place of current recommendations for treatment of caval syndrome.

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.

A cardiac and subcutaneous canine dirofilariosis outbreak in a kennel in central France.

Canine dirofilarioses are nematode infections caused by two species of the genus Dirofilaria: D. immitis and D. repens. We describe here an outbreak of D. immitis and D. repens infection in military working dogs (MWDs) housed in a kennel in the Indre department (centre of France). Out of a total of 17 dogs, 6 (35.2%) tested positive for D. immitis, D. repens or both parasites. Infested dogs were treated and prophylactic measures were implemented for the entire kennel staff. To our knowledge, this is the first documented description of an outbreak of canine cardiopulmonary dirofilariasis in the center of France, unlike in the south of this country, where D. immitis and D. repens dirofilariasis are enzootic. In France, as mosquito vectors expand their territory and new non-native vectors are introduced, it is likely that the distribution area of these two diseases of domestic and wild carnivores will be wider and underestimated.

TITLE: Un foyer de dirofilariose canine cardiaque et sous-cutanée dans un chenil du centre de la France. ABSTRACT: Les dirofilarioses canines sont des infections à nématodes causée par deux espèces du genre Dirofilaria, D. immitis et D. repens. Nous décrivons ici un foyer d'infection à D. immitis et D. repens chez des chiens militaires hébergés dans un chenil dans le département de l'Indre (centre de la France). Sur un total de 17 chiens, 6 (35,2 %) ont été testés positifs pour D. immitis, pour D. repens ou pour les deux parasites. Les chiens infestés ont été traités et des mesures prophylactiques ont été mises en place pour tout le personnel du chenil. À notre connaissance, il s'agit de la première description documentée d'un foyer de dirofilariose cardiopulmonaire canine dans le centre de la France, contrairement au sud du pays, où les dirofilarioses à D. immitis et D. repens sont enzootiques. En France, à mesure que les moustiques vecteurs élargissent leur territoire et que de nouveaux vecteurs non indigènes sont introduits, il est probable que la zone de distribution de ces deux maladies des carnivores domestiques et sauvages sera plus étendue et sous-estimée.

[Extraction invasive minimale de Dirofilaria immitis chez un chien souffrant d'un syndrome cave supérieur]. / Minimal invasive Extraktion von adulten Dirofilaria immitis bei einem Hund mit Kavalsyndrom.

INTRODUCTION: Caval syndrome due to infection with Dirofilaria (D.) immitis is a life-threatening situation, needing immediate therapeutic intervention. Severe pulmonary hypertension due to dirofilariosis was diagnosed echocardiographically in a 3.6 kg dog with heart failure and moderate hemolytic anemia. A ball of adult worms was visualized in the tricuspid valve area. Using a modified pigtail catheter, these worms were removed under fluoroscopic guidance by a transvenous approach. Already intraoperatively the hemodynamic condition improved. Subsequently, additional routine adulticide treatment was performed without complications. Over the following weeks the severe pulmonary hypertension normalized slowly but steadily. Manual extraction of adult D. immitis can be achieved with relatively simple tools and allows rapid stabilization of a critically sick patient.

INTRODUCTION: Le syndrome cave supérieur dû à une infestation à ­Dirofilaria (D.) immitis est une situation potentiellement mortelle nécessitant un traitement immédiat. Une hypertension pulmonaire sévère due à la dirofilariose a été diagnostiquée par échocardiographie chez un chien de 3,6 kg présentant une insuffisance cardiaque et une anémie hémolytique modérée. Une boule de vers adultes a été visualisée dans la région de la valvule tricuspide. En utilisant un cathéter queue de cochon modifié, ces vers ont été retirés sous guidage fluoroscopique par une approche transveineuse. Déjà durant l'opération, l'état hémodynamique s'est amélioré. Par la suite, un traitement adulticide de routine supplémentaire a été réalisé sans complications. Au cours des semaines suivantes, l'hypertension artérielle pulmonaire sévère s'est normalisée lentement mais régulièrement. L'extraction manuelle de D. immitis adultes peut être réalisée avec des outils relativement simples et permet la stabilisation rapide d'un patient gravement atteint.

Persistence of pulmonary endarteritis in canine heartworm infection 10 months after the eradication of adult parasites of Dirofilaria immitis.

Pulmonary endarteritis caused by Dirofilaria immitis and pulmonary hypertension (PH) are closely linked and the determination of PH could be validated to assess the severity and chronicity of the vascular damage, i.e. by the use of the Right Pulmonary Artery Distensibility (RPAD) Index. The aim was to evaluate the RPAD Index in dogs 10 months after the last dose of adulticide. The study included 23 client-owned dogs with heartworm brought for adulticide treatment. Echocardiographic exam was carried out to estimate worm burden, RPAD Index as well as other routine echocardiographic values on day 0 (diagnosis), day 120 (discharge), and 10 months after the last dose of adulticide. No significant differences were observed in the RPAD Index over time, neither when microfilaremic status and parasite burden were evaluated. An RPAD Index <29% was found in 52.2% of the dogs on day 0, day 120, and 10 months after the last dose of adulticide. Regarding other echocardiographic parameters, only significant differences were observed on tricuspid annular plane systolic excursion (TAPSE) values between day 0:day 120 (p = 0.008), and day 0:end of the study (p = 0.037). There was not significant improvement in pulmonary damage 10 months after the elimination of the parasites (p = 0.296), suggesting that, once the endarteritis has developed, the vascular changes are chronic and may not be reversible. The modifications of the TAPSE value suggest an improvement in the systolic function of the right ventricle after the disappearance of the worms, independently of the presence of PH. The endarteritis causes a decrease in the elasticity in the pulmonary vasculature and an increase in the resistance that, chronically, and depending on the severity, will cause the development of PH and later right heart failure. This complication of the disease is one of the most damaging and frequent, so it is necessary to adequately monitor PH in dogs undergoing adulticide treatment. Furthermore, knowing the pulmonary status could provide valuable information to help provide an objective prognosis and help assess the need to add additional treatments, once the worms have been eliminated.

Circulating and bone marrow myeloid cells containing Leishmania amastigotes in a case of advanced canine leishmaniosis.

A 5-y-old male Poodle mix was presented with intermittent vomiting, anorexia, and weight loss. Physical examination revealed emaciation, lethargy, dehydration, hypothermia, respiratory distress, and splenomegaly. Based on clinicopathologic, serologic, and parasitologic findings, diagnoses of severe leishmaniosis and dirofilariasis were made. Extracellular, intraneutrophilic, and intramonocytic Leishmania amastigotes were observed on blood smear and buffy coat smear examination. In blood smears, 0.2% of neutrophils were observed to be infected; in buffy coat smears, 0.5% of neutrophils and 0.1% of monocytes were found to be infected. Leishmania amastigotes were also found engulfed by eosinophils and neutrophil precursors in bone marrow aspiration cytology. The detection of Leishmania amastigotes in blood smears is rare, and the clinical significance is uncertain. In circulating blood, Leishmania amastigotes are primarily found phagocytized by neutrophils. Although debatable, there is growing evidence that neutrophils are used as carriers enabling the "silent entry" of the protozoa into macrophages ("Trojan horse" theory). To date, cytologic screening of blood smears for the diagnosis of canine leishmaniosis is not a routine practice. Clinical pathologists and practitioners should be aware that Leishmania amastigotes may be present in neutrophils and less frequently monocytes during blood smear evaluation; neutrophil precursors and eosinophils may also be parasitized in bone marrow specimens.

Human pulmonary dirofilariasis with secondary myocarditis.

Dirofilariasis is a little-known zoonosis, with dogs and cats as definitive hosts. It is caused by nematodes and transmitted by mosquito bites. We report the case of a 67-year-old man with a consumptive syndrome with two subpleural pulmonary opacities. A transthoracic lung biopsy revealed a Dirofilaria worm. Myocardial nuclear magnetic resonance (NMR) demonstrated dilated cardiomyopathy after myocarditis related to dirofilariasis. Human infection is rare and occurs accidentally. The most common radiological alteration is a mainly subpleural coin lesion. Dirofilariasis is a neglected emergent disease and knowledge about it is important for differential diagnoses from neoplastic pulmonary nodules.

Human pulmonary dirofilariasis with secondary myocarditis

Abstract Dirofilariasis is a little-known zoonosis, with dogs and cats as definitive hosts. It is caused by nematodes and transmitted by mosquito bites. We report the case of a 67-year-old man with a consumptive syndrome with two subpleural pulmonary opacities. A transthoracic lung biopsy revealed a Dirofilaria worm. Myocardial nuclear magnetic resonance (NMR) demonstrated dilated cardiomyopathy after myocarditis related to dirofilariasis. Human infection is rare and occurs accidentally. The most common radiological alteration is a mainly subpleural coin lesion. Dirofilariasis is a neglected emergent disease and knowledge about it is important for differential diagnoses from neoplastic pulmonary nodules.

Multidetector computed tomographic pulmonary angiography in a cat with fatal heartworm disease.

A 17-month-old neutered male domestic shorthair cat was referred for a computed tomographic (CT) study of the thorax due to respiratory distress. Multidetector CT angiography showed a multifocal interstitial ground glass opacity, tortuous and blunted pulmonary arteries consistent with thromboembolism with perivascular lung infiltration and hypoventilation in multiple lung lobes. A blood antigen test was positive for Dirofilaria immitis. The cat's clinical condition rapidly declined and the owners elected euthanasia. The histopathologic examination confirmed heartworm disease with parasitic pulmonary thromboembolism.