Change in the Distribution Pattern of Dirofilaria immitis in Gran Canaria (Hyperendemic Island) between 1994 and 2020.

Dirofilariosis is a zoonotic disease that mainly affects dogs and cats, with a high risk to public health. The island of Gran Canaria (Spain) has been shown to be a hyperendemic area of infection and, therefore, a model for studying the evolution of the disease. The objective of this study was to track the prevalence and distribution of heartworm in dogs, cats, and residents of Gran Canaria from 1994 to 2020, using published and unpublished data. Blood samples from 5841 dogs, 1203 cats, and 1604 humans were collected in the years analyzed, considering geographical and isoclimatic factors. In 1994, a prevalence of Dirofilaria immitis of 67.02% in dogs was reported, while in 2020 it was 15.81%. In cats, the seroprevalence in 2010 was 33.03%, compared to 17.20% in 2020. The incidence of D. immitis in humans in 2008 was 18.66%, while in 2020 it was 8.27%. For all study groups, temperate cold zone (TC) and temperate mild zone (TM) climates had the highest prevalence. Throughout these 20 years, the prevalence of heartworm disease has decreased. Despite this, it continues to be a hyperendemic island. This study highlights the importance of using the "One Health" perspective and the risks of contagion of the disease.

Association between Thoracic Radiographic Changes and Indicators of Pulmonary Hypertension in Dogs with Heartworm Disease.

Pulmonary hypertension (PH) is a consequence of pulmonary endarteritis during infection with Dirofilaria immitis in dogs. Echocardiography is the technique of choice but is not always accessible to all clinicians. This study aimed to evaluate the association of the radiological findings in dogs with heartworm disease and the presence or absence of echocardiographically characterised PH. The study included 62 heartworm-infected dogs that underwent thoracic radiographs and echocardiography. The studied dogs showed moderate to severe PH when the Right Pulmonary Artery Distensibility (RPAD) Index was <29.5%. The RPAD Index was used for comparison with thoracic radiographs. The Vertebral Heart Size (VHS), right cranial pulmonary artery passing through the fourth rib in the laterolateral projection (CrPA/R4) ratio, and right caudal pulmonary artery to the ninth rib in the dorsoventral projection (CdPA/R9) ratio showed significant differences between dogs with/without PH (p < 0.001). Sensitivity (sen) and specificity (sp) cut-off values were obtained: VHS ≥ 9.53 (sen 93.75%, sp 63.33%); CrPA/R4 ≥ 1.08 (sen 87.5%, sp 70%); and CdPA/R9 ≥ 1.10 (sen 96.88%, sp 76.66%). The CrPA/R4 and CdPA/R9 ratios showed potential as a preliminary screening tool for PH in heartworm-infected dogs, suggesting that they may reliably indicate the presence of PH and guide the decision for further diagnostic testing.

Current State of Canine Heartworm in Portugal.

The favourable geo-climatic conditions in Portugal have made it highly conducive to the development of Dirofilaria immitis in dogs, leading to its identification as an endemic region. This nematode is rapidly spreading across Europe, particularly in northeastern countries. The objective of this study was to provide an updated assessment of the prevalence of this disease in Portuguese dogs, analysing the results in relation to epidemiological and geo-environmental factors, and to identify potential risk factors. A total of 1367 dogs from all continental and insular districts were included in the study and tested for D. immitis antigens. The overall prevalence was found to be 5.9%. It was observed that the disease is spreading northward, with previously unaffected districts now reporting cases, and that the prevalence in coastal districts exceeded that of inland ones. Notably, the Aveiro district exhibited a significant increase in D. immitis prevalence, while in certain districts such as Setúbal, Santarém, Madeira, or Faro, a stabilisation or decrease in prevalence was noted. Furthermore, outdoor and older dogs were found to be at a higher risk of infection. No positive cases were detected in the Azores. Most of the infected dogs were located in areas of high and medium risk of infection. This study underscores the importance of implementing pharmacological prophylaxis, vector control strategies, and public awareness programs to control the spread of this zoonotic disease.

Machine Learning Techniques for Canine Myxomatous Mitral Valve Disease Classification: Integrating Anamnesis, Quality of Life Survey, and Physical Examination.

Myxomatous mitral valve disease (MMVD) is a prevalent canine cardiac disease typically diagnosed and classified using echocardiography. However, accessibility to this technique can be limited in first-opinion clinics. This study aimed to determine if machine learning techniques can classify MMVD according to the ACVIM classification (B1, B2, C, and D) through a structured anamnesis, quality of life survey, and physical examination. This report encompassed 23 veterinary hospitals and assessed 1011 dogs for MMVD using the FETCH-Q quality of life survey, clinical history, physical examination, and basic echocardiography. Employing a classification tree and a random forest analysis, the complex model accurately identified 96.9% of control group dogs, 49.8% of B1, 62.2% of B2, 77.2% of C, and 7.7% of D cases. To enhance clinical utility, a simplified model grouping B1 and B2 and C and D into categories B and CD improved accuracy rates to 90.8% for stage B, 73.4% for stages CD, and 93.8% for the control group. In conclusion, the current machine-learning technique was able to stage healthy dogs and dogs with MMVD classified into stages B and CD in the majority of dogs using quality of life surveys, medical history, and physical examinations. However, the technique faces difficulties differentiating between stages B1 and B2 and determining between advanced stages of the disease.

Usefulness of Tissue Doppler Imaging for the Evaluation of Pulmonary Hypertension in Canine Heartworm Disease.

BACKGROUND: Dirofilaria immitis is a nematode that produces proliferative pulmonary endarteritis in dogs due to direct contact of the adult parasites with the intima layer of the pulmonary arteries, leading to irreversible severe structural damage and sustained pulmonary hypertension (PH), which can produce severe cardiorespiratory disorders. The purpose of this study was to assess the diagnostic value of the echocardiography tissue Doppler imaging (TDI) in determining the presence of PH in dogs with heartworm disease. METHODS: There were 116 heartworm-infected dogs with PH and 33 healthy dogs included in the study. Based on the right pulmonary artery distensibility index (RPADi) < 29.5%, PH was present in 47.4% of infected dogs. Additionally, the animals were evaluated using other standard alternative echocardiographic measures to estimate PH. Moreover, a total of eight echocardiographic measurements were analysed using the TDI to determine its usefulness in diagnosing PH (E', A', S, E':A', global TDI, HRI-IVCT, HRI-IVRT, R-TEI). RESULTS: The TDI measurements showed significant differences between dogs with and without PH, demonstrating a positive correlation with respect to the RPADi. In addition, cut-off values for the detection of PH with excellent sensitivity and specificity were found for E':A', global TDI, HRI-IVCT, HRI-IVRT and R-TEI. CONCLUSIONS: The TDI mode may be useful as an adjunct diagnostic method for the determination of PH in dogs with Dirofilaria immitis.

Radiographic Left Atrial Size Measurement of Dogs in Different Mitral Valve Disease Stages with Four Different Methods.

The left atrial size increases (LAS) in patients with mitral valve disease (MVD) as the disease progresses. The vertebral left atrial size (VLAS), the modified-vertebral left atrial size (M-VLAS), and the radiographic left atrial dimension (RLAD) are methods reported to assess LAS on dogs' radiographs. All these methods transform the LAS into vertebral units. The thoracic inlet (TI) has been used as a reliable reference point to measure the cardiac silhouette of dogs with MVD in different stages. The objective of this study was to assess the clinical utility of measuring a dog LAS on right thoracic X-rays using the TI as a reference and determine whether it could differentiate dogs in different MVD stages. LAS was divided by the TI to obtain the thoracic inlet left atrial score (TILAS). This was a retrospective observational study including 135 apparently healthy dogs performed to assess their LAS with four different methods: VLAS, M-VLAS, RLAD, and TILAS. Thirty-six dogs from the general population were selected and compared to 100 dogs in different MVD stages. The TILAS was significantly different between the control dogs and MVD dogs, increasing with the disease stage: control dogs 0.51 ± 0.08, B1 0.57 ± 0.14, B2 0.75 ± 0.13, and C 0.84 ± 0.18. VLAS, M-VLAS, and RLAD also increased as the disease progressed, as shown in previous studies. The TILAS accuracy to distinguish MVD dogs with cardiac enlargement was comparable to VLAS, M-VLAS, and RLAD (AUC 0.91 vs. 0.93, 0.90, and 0.94 respectively). A TILAS > 0.8 can identify dogs with cardiac enlargement secondary to MVD.

Assessment Heartworm Disease in the Canary Islands (Spain): Risk of Transmission in a Hyperendemic Area by Ecological Niche Modeling and Its Future Projection.

Heartworm disease is a vector-borne zoonotic disease caused by Dirofilaria immitis. The Canary Islands (Spain), geolocated close to the coast of Western Sahara, is an archipelago considered hyperendemic where the average prevalence in domestic dogs is high, heterogeneous, and non-uniform. In addition, Culex theileri has been reported as a vector of the disease on two of the most populated islands. Our aim was to develop a more accurate transmission risk model for dirofilariosis for the Canary Islands. For this purpose, we used different variables related to parasite transmission; the potential distribution of suitable habitats for Culex spp. was calculated using the ecological niche model (ENM) and the potential number of generations of D. immitis. The resulting model was validated with the geolocation of D. immitis-infected dogs from all islands. In addition, the impact of possible future climatic conditions was estimated. There is a risk of transmission on all islands, being high in coastal areas, moderate in midland areas, and minimal in higher altitude areas. Most of the dogs infected with D. immitis were geolocated in areas with a high risk of transmission. In 2080, the percentage of territory that will have been gained by Culex spp. is small (5.02%), although it will occur toward the midlands from coastal areas. This new model provides a high predictive power for the study of cardiopulmonary dirofilariosis in the Canary Islands, as a hyperendemic area of the disease, and can be used as a tool for its prevention and control.

The Thoracic Inlet Length as a Reference Point to Radiographically Assess Cardiac Enlargement in Dogs with Myxomatous Mitral Valve Disease.

The diagnostic value of the vertebral heart size (VHS) in dogs with mitral valve degeneration (MVD) is compromised when middle thoracic vertebral anomalies are present. The objective of this study was to assess the use of the thoracic inlet heart score (TIHS) to identify left heart enlargement (LHE) secondary to MVD. The cardiac silhouette of 50 clinically healthy dogs and 106 MVD dogs in different stages was assessed on a right lateral chest radiograph. The TIHS and VHS value were calculated for each patient and compared. The TIHS was significantly different between the control dogs and the dogs with MMVD, increasing with disease stage, control 2.91 ± 0.23, Stage B1 2.98 ± 0.36, B2 3.25 ± 0.34, and C 3.53 ± 0.36, p < 0.05. A THIS ≥3.3 showed 69% sensitivity and 81% specificity to identify LHE. The TIHS showed moderate correlation with the VHS, LA/Ao, and LVIDDN 0.59, 0.42, and 0.62, respectively. The intraobserver and interobserver agreement were almost perfect, 0.96, and substantial, 0.73. The TIHS method can be used to identify LHE secondary to MMVD on dogs' thoracic radiographs.

Usefulness of NT-proBNP in dogs with heartworm: could this biomarker be useful to evaluate pulmonary hypertension?

BACKGROUND: In recent years, the usefulness of echocardiography and serum biomarkers in the diagnosis of pulmonary hypertension (PH) in dogs with heartworm disease has been studied. Previously, N-terminal pro B-type natriuretic peptide (NT-proBNP) has shown high concentrations in dogs with heart disease and/or PH as well as its usefulness as a prognostic indicator, but it has never been evaluated in the diagnosis and prognosis of PH in dogs with heartworm disease. The aim was to evaluate the serum concentrations of NT-proBNP in dogs infected by Dirofilaria immitis to determine its usefulness as a tool to detect precapillary PH. METHODS: NT-proBNP was determined in 50 heartworm-infected dogs. Presence/absence of PH was determined echocardiographically, using the Right Pulmonary Artery Distensibility Index (RPAD Index) and the systolic flow of tricuspid regurgitation mainly, together with other echocardiographic measurements following the guidelines of the American College of Veterinary Internal Medicine (ACVIM) for the diagnosis of PH. Other epidemiological parameters (breed, age, sex, status: client-owned or shelter dogs) and clinical parameters (microfilaremia, parasite burden, presence of symptoms, body condition) were collected as well. RESULTS: Moderate-severe PH was present in 40% of the dogs (RPAD Index < 29.5%), NT-proBNP concentrations being significantly higher compared with dogs that did not have PH. A cutoff for NT-proBNP of ≥ 1178.45 pmol/l showed a sensitivity of 64.3% and a specificity of 95.5% for the presence of moderate-severe PH. Older dogs and dogs from shelters showed significantly higher NT-proBNP concentrations. Dogs with symptoms and low body condition presented significantly higher NT-proBNP concentrations as well. CONCLUSIONS: The determination of NT-pro-BNP concentration can be a useful tool in the diagnostic work-up of dogs with heartworm disease and associated PH and can help to identify animals in the more advanced stage of this disorder.

Feline heartworm disease and environmental allergens hypersensitivity: is there a link?

BACKGROUND: Cats can be infected by Dirofilaria immitis, the causative agent of heartworm disease, characterized by respiratory signs, airway hyperreactivity, remodelling and inflammation. Allergy is a multifactorial pathology, and the role of a number of helminth parasites in the development of allergies in humans and other species has been demonstrated in many studies. The aim of the present study was to verify whether cats seropositive for D. immitis present hypersensitivity to some environmental allergens. METHODS: Blood samples were collected from 120 cats and tested for the presence of specific immunoglobulin G antibodies against D. immitis and for hypersensitivity to 20 allergens, using commercial allergen test kits. RESULTS: Of the 120 cats tested, 72 (60.0%) were seropositive for anti-D. immitis IgG and 55 (45.8%) showed clinical signs of heartworm disease of a respiratory nature. The results of testing with the allergen kits showed that 50.8% of cats were seropositive for ≥ 1 allergens, with the most common allergens being Dermatophagoides farinae (25.8%), Dermatophagoides pteronyssinus (20.0%), Malassezia (17.5%) and Ctenocephalides felis (14.2%). The prevalence of allergies was significantly higher-by almost threefold-in cats seropositive for D. immitis (68.1% vs. 25%). There were no significant differences between the prevalence of allergic cats and presence/absence of symptoms, and the results confirmed that symptoms were not a decisive factor for the presence of allergies. The risk for developing allergies was 6.3-fold higher in cats seropositive for D. immitis than in cats that were seronegative, confirming that seropositivity for D. immitis is a risk factor. CONCLUSIONS: Cats with confirmed heartworm can develop serious respiratory signs, potentially leading to progression to permanent lung injury and predisposing cats to hyperresponsive airway disease. Previous studies have shown that seropositivity for D. immitis and Wolbachia is related to the presence of bronchoconstriction and bronchospasm in the affected cat. The results support the suspicion that contact with D. immitis may be a risk factor for the presence of allergies.

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.

Echocardiographic Assessment of the Pulmonary Vein to Pulmonary Artery Ratio in Canine Heartworm Disease.

Background:Dirofilaria immitis produces proliferative pulmonary endarteritis and pulmonary thromboembolism in infected dogs. The pulmonary vascular lesions lead to irreversible and persistent structural damage and, as a consequence, sustained precapillary pulmonary hypertension (PH). The purpose of this study was to assess the diagnostic value of the pulmonary vein to pulmonary artery ratio (PV:PA ratio) to determine moderate or severe PH (>50 mmHg) in dogs with heartworm disease. METHODS: A total of 151 naturally heartworm-infected and 66 healthy dogs were included in the study. The presence/absence of PH was based on the right pulmonary artery distensibility index (RPAD index < 29.5%), and the PV:PA ratio was echocardiographically measured by the time-motion mode (M mode) and two-dimensional mode (2D mode). Other echocardiographic parameters were also assessed (pulmonary trunk to aorta ratio, tricuspid regurgitation pressure gradient, and AT:ET ratio). RESULTS: The results of the PV:PA ratio showed a highly positive correlation between the M and 2D modes (r = 0.928). The PV:PA ratio obtained by the M mode was identified as the strongest predictor for RPAD index (R2 0.628, p < 0.0001) with a good diagnostic accuracy (AUC = 0.99). The results of PV/PA by the 2D mode showed a similar prediction for the RPAD index (R2 0.606, p < 0.0001) with a good diagnostic accuracy (AUC = 0.98). Both of the 2D and M modes' PV:PA ratios decreased significantly with the presence of PH. A cut-off value of ≤0.845 showed high sensitivity and specificity for the M mode (97% and 94%, respectively) and the 2D mode (96% and 93%, respectively). CONCLUSIONS: The PV:PA ratio may be useful as a complementary diagnostic method for the estimation of moderate or severe PH in dogs with heartworm.

The Thoracic Inlet Heart Size, a New Approach to Radiographic Cardiac Measurement.

In 1995, the Vertebral Heart Size (VHS) method for measuring the cardiac silhouette on thoracic radiographs was published, becoming a quantifiable and objective reference way of assessing the heart size. Since then, many studies have showed that VHS is influenced by breed variations, vertebral malformations, reference points selection, and short and long axes dimensions conversion into vertebral units. The Thoracic Inlet Heart Size (TIHS) normalizes heart size to body size using the thoracic inlet length. The lengths of the long and short axes of the heart of 144 clinically normal dogs were measured on right lateral thoracic radiographs. The sum of both measures was indexed to the thoracic inlet length. For comparison, dogs of the most represented breeds in our hospital were selected to measure their heart size using the TIHS protocol. The mean TIHS value for the population studied was 2.86 ± 0.27, and 90% of dogs had a TIHS value of less than 3.25. There was no difference in TIHS between male and female, and between small and large dogs (p-value < 0.01). There was no difference in the TIHS value between Yorkshire Terrier, Chihuahua, and Labrador retriever breeds, and between each of those three breeds and the general population. The TIHS is a simple, straightforward and accurate way to measure heart size.

Right Ventricle Strain Assessed by 2-Dimensional Speckle Tracking Echocardiography (2D-STE) to Evaluate Pulmonary Hypertension in Dogs with Dirofilaria immitis.

Echocardiographic assessment of the right ventricle is helpful for analysing the pathophysiology of heartworm disease and detecting pulmonary hypertension (PH) in dogs. In veterinary cardiology, the study of myocardial deformation using two-dimensional speckle tracking (2D-STE) echocardiography has become increasingly acknowledged as useful for quantifying right ventricular function. The aim of this study was to evaluate the usefulness of myocardial deformation strain of the right ventricular free wall (FWS), global deformation strain of the right ventricle, including the interventricular septum (GS), and tissue motion annular displacement of the tricuspid valve (TMAD) in a cohort of dogs with heartworm (Dirofilaria immitis) disease and to determine cut-off values for detecting the presence of PH. Out of the 93 dogs tested, 71% were diagnosed with heartworm infection. PH was identified in 41% of the infected dogs following the American College of Veterinary Internal Medicine (ACVIM) guidelines, based on the peak tricuspid regurgitation velocity to calculate the tricuspid regurgitation pressure gradient (TRPG), while other routine measurements were used, including the right pulmonary artery distensibility index (RPADi). The 2D-STE mode measurements were determined using Right Ventricular Automated Function Imaging (RV AFI®) software. The statistical analysis showed significant differences in the studied parameters among dogs with and without PH. Additionally, sensitivity (sen) and specificity (sp) cut-off values were obtained (GS ≥ -21.25%, sen 96%, sp 86.4%; FWS ≥ -21.95%, sen 92.56%, sp 95.5%; TMAD ≤ 0.85 cm, sen 70.4%, sp 83.3%). These results demonstrated that GS, FWS, and TMAD could be used as supplementary and alternative variables to conventional echocardiographic measurements when detecting PH in dogs with heartworm disease.

Decision making under uncertainty in the diagnosis and management of Alzheimer's Disease in primary care: A study protocol applying concepts from neuroeconomics.

Background: The current management of patients with Dementia, primarily with Alzheimer's Disease (AD) is rapidly evolving. However, limited information is available about the current gaps and decision-making in primary care. Objectives: To evaluate factors associated with gaps, risk preferences regarding diagnostic and therapeutic choices in the management of patients with AD by primary care physicians (PCP) from across Canada. Methods: We propose a non-interventional, cross-sectional pilot study involving 120 primary care physicians referred from the College of Family Physicians of Canada to assess diagnostic and therapeutic decisions in the management of ten simulated AD-related case-scenarios commonly encountered in clinical practice. We initially describe the current landscape and gaps regarding diagnostic and therapeutic challenges in the management of patients with AD in primary care. Then, we provide concepts from behavioral economics and neuroeconomics applied to medical decision-making. Specifically, we include standardized tests to measure risk aversion, physicians' reactions to uncertainty, and questions related to risk preferences in different domains. Finally, we summarize the protocol to be implemented to address our goals. The primary study outcome is the proportion of participants that elect to defer initial investigations to the specialist and the associated factors. Secondary outcomes include the proportion of PCP willing to order cerebral spinal fluid studies, PET scans, or initiate treatment according to the simulated case-scenarios. The study will be conducted in English and French. Conclusions: The study findings will contribute a better understanding of relevant factors associated with diagnostic and therapeutic decisions of PCP in the management of AD, identifying participant's preferences and evaluating the role of behavioral aspects such tolerance to uncertainty, aversion to ambiguity, and therapeutic inertia.

Comprehensive Map of Canine Angiostrongylosis in Dogs in Spain.

Canine angiostrongylosis is an emerging disease caused by Angiostrongylus vasorum, mainly affecting wild carnivores and dogs. In Spain, there are studies reporting infections in foxes, wolves, and badgers in different regions of the country. However, there are hardly any publications on its prevalence in dogs. The aim of this study was to complete and update the epidemiologic map of A. vasorum in dogs in Spain. A total of 5619 canine blood samples from all autonomous cities and provinces of Spain were collected and tested for the presence of circulating A. vasorum antigens. The overall apparent prevalence of canine A. vasorum infection in Spain was 1.39%. No significant differences were found for sex or age, but significant differences between outdoor and indoor/outdoor dogs were found. A high prevalence was also observed in the northern third of the country, where an oceanic climate prevails, being humid and rainy and where abundant vegetation can be found, thus favoring the proliferation of intermediate hosts. The results suggest that A. vasorum canine infections are heterogeneously present in a large part of the territory, demonstrating its expansion throughout the country, and therefore, awareness and prevention campaigns for this disease should be promoted.

Evaluation of Pulmonary Hypertension in Dogs with Heartworm Disease Using the Computed Tomographic Pulmonary Trunk to Aorta Diameter Ratio.

Dirofilaria immitis causes proliferative pulmonary endoarteritis that leads to the appearance of chronic precapillary pulmonary hypertension (PH) in dogs. Pulmonary trunk to aorta ratio (PT:Ao ratio) obtained by computed tomography (CT) was studied and the quantitative measure of the diameters of the pulmonary trunk (PT), the descending thoracic aorta (DAo) and ascending thoracic aorta (AAo) were evaluated for the determination of the presence of moderate to severe PH in 59 dogs. The diagnosis of PH was echocardiographically determined, based on the determination of the right pulmonary artery distensibility (RPAD) index (<29.5%), and compared with other parameters for estimating PH. The results showed a very high concordance: 0.976 (p-value 0.000) between the two CT methods (PT:DAo and PT:AAo) with an excellent intraclass correlation coefficient > 0.95. Moreover, cut-off values of ≥1.111 for PT:DAo, and ≥1.057 for PT:AAo were determined for dogs with an RPAD index < 29.5%, which suggests a cut-off value between healthy dogs and the presence of PH. As has been previously published, The PT:Ao ratios did not determine the presence of mild PH, so the measurements cannot be considered useful for the early diagnosis of PH in dogs with heartworm.

What Has Happened to Heartworm Disease in Europe in the Last 10 Years?

Heartworm disease caused by Dirofilaria immitis is a vector-borne disease that affects canids and felids, both domestic and wild, throughout the world. It is a chronic disease which causes vascular damage in pulmonary arteries, and in advanced stages, the presence of pulmonary hypertension and right-sided congestive heart failure can be evidenced. Moreover, pulmonary thromboembolism is caused by the death of the worms, which can be lethal for the infected animal. Furthermore, it is the causative agent of human pulmonary dirofilariosis, being a zoonotic disease. The aim of this review was to update the current epidemiological situation of heartworm in Europe in dogs, cats, wild animals, and vectors insects, and to analyse the factors that may have contributed to the continuous spread of the disease in the last decade (2012-2021). In Europe, the disease has extended to eastern countries, being currently endemic in countries where previously only isolated or imported cases were reported. Furthermore, its prevalence has continued to increase in southern countries, traditionally endemic. This distribution trends and changes are influenced by several factors which are discussed in this review, such as the climate changes, presence of vectors in new areas, the appearance of new competent vector species in the continent, increased movement of pets that travelled to or originated from endemic countries, the urbanisation of rural areas leading to the formation of so-called "heat islands", or the creation of extensive areas of irrigated crops. The continuous expansion of D. immitis must be monitored, and measures adapted to the situation of each country must be carried out for adequate control.

Evaluation of acute phase proteins, adiponectin and endothelin-1 to determine vascular damage in dogs with heartworm disease (Dirofilaria immitis), before and after adulticide treatment.

Previous studies have shown the existence of an acute phase response in dogs with heartworm (Dirofilaria immitis), probably caused by the vascular inflammation that occurs during the pathogenesis of this disease. In addition, it has been seen that this acute phase response persists after finishing treatment, especially in dogs with pulmonary hypertension (PH). Furthermore, echocardiographic studies have shown that PH and endarteritis appear to persist for at least 10 months after completion of adulticide treatment, suggesting that the vascular changes in these dogs may not be reversible. Therefore, the objective of this study was to evaluate the serum concentrations of different positive acute phase proteins (APP) [C reactive-protein (CRP), haptoglobin and ferritin] and negative APP (albumin and paraoxonase-1 (PON-1)), and the usefulness of the endothelin-1 (ET-1) and adiponectin, in dogs infected by D. immitis to evaluate their usefulness as diagnostic biomarkers of vascular damage and PH and their progression throughout therapy up to 7 months after the end of adulticide treatment. Twenty-five heartworm-infected dogs received adulticide treatment, and serum measurements were performed on the day of diagnosis (day 0), day of discharge (day 90), and 6 months after discharge (day 270). In addition, presence or absence of PH was also echocardiographically determined using the Right Pulmonary Artery Distensibility Index. PH was present in 44% of the dogs on day 0 and day 90, and in 48% of dogs on day 270. Alterations were observed in the concentrations of all APP throughout the study, persisting the alterations in PON-1 and ferritin on day 270. Depending on the presence or absence of PH, CRP showed significant differences throughout the study, as did ET-1. On the other hand, adiponectin did not show variations throughout the study, so it did not seem a useful marker in this disease. These results could reflect the possible persistence of vascular inflammation up to 7 months after finishing treatment, whether or not there was PH, and consolidate the study of APP as useful markers in heartworm disease. Moreover, persistent PH could be the consequent clinical manifestation in dogs with more severe vascular alterations so the study of APP, especially CRP, and ET-1 could be especially advantageous in these patients in the early evaluation of the disease, as well as for the determination of disease severity, monitoring therapeutic responses, and predicting outcomes.

Seroprevalence of Feline Heartworm in Spain: Completing the Epidemiological Puzzle of a Neglected Disease in the Cat.

Feline heartworm is a vector-borne zoonotic disease caused by Dirofilaria immitis. It is a cosmopolitan disease that is continuously expanding. Spain is considered an endemic country; however, although there are many published studies in dogs, feline heartworm has been poorly studied in this country. Thus, the objective was to analyze the exposure to D. immitis throughout Spain to complete the epidemiological map in the feline species. For this, 6,588 feline serum samples were analyzed for the presence of D. immitis antigens and antibodies against D. immitis and Wolbachia. The results were analyzed according to sex, age, breed, habitat, origin (owned or shelter cats), presence of clinical signs, use of preventive, location and climatology. The results showed a prevalence of 0.5% and a seroprevalence of 9.4%. The highest antibody seroprevalences were reported in the Canary Islands and the Balearic Islands (19.2 and 16%, respectively), as well as in the autonomous communities located on the Mediterranean coast (9.2-11.2%). Seropositive cats were found in both indoor and outdoor cats, and from 6 months of age. Furthermore, only 5.8% of cats received regular prophylactic treatment. The results show that feline dirofilariasis is widely distributed throughout the national territory and corroborate that, where infected dogs are present, there are cats exposed to the parasite. It is necessary to implement efficient awareness and prophylaxis measures to control the incidence and expansion of feline heartworm in Spain.