Search Results (42)

Canine dirofilariasis, caused by Dirofilaria immitis and Dirofilaria repens, is an emerging vector-borne disease of increasing veterinary and zoonotic importance. Rapid and species-specific detection is essential for effective clinical management and epidemiological surveillance. This study aimed to develop and diagnostically evaluate two novel species-specific loop-mediated isothermal amplification (LAMP) assays for the direct detection of D. immitis and D. repens in canine whole blood, performed in parallel in separate reactions, with emphasis on simplified and potentially near-point-of-care applicability. Primers targeting mitochondrial COI and NADH gene regions were designed and validated. In silico specificity analysis against 13 filarioid species confirmed the absence of non-specific primer binding. A direct closed-tube LAMP protocol using sodium hydroxide–Chelex-100 lysis was optimized, enabling amplification without conventional DNA extraction while reducing contamination risk and processing time to under 60 min. Relative diagnostic performance was evaluated relative to quantitative real-time PCR (qPCR) results. Using purified DNA, the D. repens assay achieved 100% relative sensitivity and relative specificity, whereas the D. immitis assay showed 94.5% relative sensitivity and 100% specificity. In direct whole-blood assays, relative specificity remained 100% for both targets, while sensitivity decreased to 90.9% for D. immitis and 77.42% for D. repens, with most false-negative reactions associated with high qPCR Ct values (>30). These findings demonstrate that the proposed assays provide a rapid and practical molecular diagnostic approach with potential applicability for point-of-care veterinary testing. Full article

The northward expansion of Dirofilaria spp. is a current medical and veterinary concern. However, it is unclear how far north the parasite has spread in Western Siberia and what species of mosquito can carry and transmit it. This study examined Dirofilaria spp. infection in Aedes mosquitoes in the taiga zone of the Irtysh Basin. The mosquito species were identified based on morphology, and Dirofilaria spp. were identified using PCR. Of the 13 habitats surveyed, 24 of 2205 mosquito samples were infected with D. repens and 1 with Dirofilaria sp. The highest infection rate (~7.6) was recorded in Tobolsk, Tyumen region, at 58.4° N. Mosquito infection was recorded as far north as 61° N in Khanty-Mansiysk. The presence of the infective L3 stage of the parasite was recorded up to 60° N in Bobrovsky. Nine species of mosquitoes were found to be infected with D. repens: Aedes rossicus, Aedes behningi, Aedes cantans, Aedes communis, Aedes cyprius, Aedes euedes, Aedes excrucians, Aedes flavescens, and Aedes sticticus. Two of these species, Ae. behningi and Ae. communis, were competent vectors of the parasite. Thus, D. repens has successfully adapted to the Aedes mosquito in the taiga zone of Siberia. Full article

Dirofilaria repens is the leading cause of subcutaneous (dogs) and subcutaneous/ocular dirofilariosis (humans) in the Old World. Despite its rapid geographical spread, driven by climate change, the emergence of new invasive vectors (Aedes albopictus) and growing interest in its study due to the emergence of new cases in areas previously free of the parasite, amongst other factors, scientific research into this pathogen remains limited. This study provides the first longitudinal bibliometric analysis of global research on D. repens (1955–2025). Data from Web of Science and Scopus were processed using PRISMA and RAMIBS protocols, resulting in a normalized corpus of 624 documents analyzed via science mapping techniques. The field exhibits a sustained annual growth rate of 3.79%, transitioning into an exponential expansion phase in 2011. While Italy retains historical leadership, spatial analysis confirms a research displacement towards Central and Eastern Europe (Germany, Poland). Thematic evolution reveals a structural shift from isolated clinical case reports to a multidisciplinary ecosystem dominated by molecular epidemiology, vector competence, and surveillance. Dirofilaria repens has gone from being a minor and neglected issue to having a significant number of reports and studies subject to interest in addressing the disease that results from its infection in different hosts. However, the intellectual structure exposes an operational fragmentation between clinical medicine and medical entomology. Future research must overcome national silos and integrate reservoir management with vector control, transforming the current reactive approach into a predictive preventive system aligned with the One Health framework. Full article

Dirofilariosis, a parasitic disease caused by nematodes of the genus Dirofilaria, primarily affects dogs but can also infect other carnivores and, more rarely, humans. In Europe, the most commonly involved species are D. immitis and D. repens, transmitted through the bites of mosquito vectors. This study, conducted in Tulcea County between April and October 2024, aimed to determine the prevalence of D. immitis and D. repens in mosquitoes. A total of 1507 mosquitoes were collected and grouped into 76 pools, and subsequently molecular analysis was carried out using qPCR. The estimated infection rate (EIR) was calculated using statistical methods available in the ‘binGroup’ package in R, which allow the determination of the point estimate and confidence interval (CI) for a single binomial proportion in group testing. The study revealed a high infection rate with D. immitis (48%), while D. repens was identified in only two pools. The species with the highest vector potential was Anopheles maculipennis (PTP = 75%, EIR = 0.1168 with both Dirofilaria species), followed by Aedes vexans. Notably, Aedes albopictus was identified for the first time in Tulcea, and all individuals were positive for D. immitis. Simulations of local thermal conditions using the proposed model show that the favorable time window for mosquitoes will increase until 2100. Our results indicate an established and active transmission cycle of D. immitis in the region, a situation projected to intensify with climate change requiring urgent monitoring. Full article

Human subcutaneous dirofilariasis caused by Dirofilaria repens is an emerging zoonotic parasitic infection increasingly observed in southern Europe. We report a case of a woman from western Sicily, who likely acquired the infection locally through a mosquito bite. The high prevalence of D. repens in the local canine population (up to 20.4%) suggests a role of dogs as a probable reservoir for transmission to humans in the local population. With ultrasound analysis being inconclusive, only after surgical removal was the presence of an adult worm evident, and only after molecular analysis through DNA sequencing of the cytochrome oxidase subunit I gene (COI) could a definitive D. repens infection diagnosis be obtained. This case highlights the need for enhanced vector control, animal health surveillance and public awareness to limit the transmission to humans of D. repens. A correct parasitological diagnosis would be imperative for the recognition of human cases. Full article

We report the first confirmed case of persistent microfilaremia in a human host infected with Dirofilaria repens. A 54-year-old woman from an endemic area in Croatia presented with peripheral eosinophilia and dermatological symptoms. Over four months, microfilariae were repeatedly detected in her blood using thick smears and Knott’s test, and the diagnosis was molecularly confirmed via COI gene sequencing and detection of Wolbachia endosymbionts. This case provides compelling evidence that D. repens can sustain a complete or near-complete life cycle in humans under specific conditions. Our findings have significant implications for clinical diagnostics, One Health surveillance, and public health interventions. Full article

Wild animals often serve as reservoirs for vector-borne zoonoses, which are on the rise worldwide but have not yet been sufficiently researched. Vector-borne zoonoses, such as those caused by Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, and Dirofilaria immitis, are a growing public health concern due to their increasing incidence and broad host range. The aim of this study was to determine the prevalence and risk factors for vector-borne bacterial (borreliosis, anaplasmosis, ehrlichiosis) and parasitic (dirofilariasis) pathogens and to detect some of these pathogens in the red fox (Vulpes vulpes) population in Croatia. A total of 179 blood samples from foxes from nine districts were analysed. The SNAP ^® 4Dx ^® Plus rapid test was used to detect circulating D. immitis antigen and antibodies against B. burgdorferi, A. phagocytophilum/Anaplasma platys, and Ehrlichia canis/Ehrlichia ewingii. Circulating D. immitis antigen was detected in 6.70% of the samples (95% CI: 3.20–10.19%), while antibodies against A. phagocytophilum/A. platys were found in 10.06% (95% CI: 5.8–14.25%). Only one sample was positive for B. burgdorferi, while no antibodies were detected for E. canis/E. ewingii. Spatial analysis revealed statistically significant differences in prevalence by geographical region (district) and age, while no significant correlations were found. In the standard PCR analysis, DNA of D. immitis was not detected in any of the eight positive and eight negative SNAP ^® 4Dx ^® Plus samples. D. repens, A. reconditum, or co-infections were also not detected by PCR. Of the nine samples that tested positive for A. phagocytophilum/A. platys antibodies, four were confirmed to be positive for A. phagocytophilum by nested and semi-nested PCR targeting the 16S rRNA and GroEL genes. Phylogenetic analysis revealed similarities with various European strains, including zoonotic strains. This study is the first molecular detection of A. phagocytophilum from blood samples of red foxes in Croatia. The results show that red foxes are not free from infections such as anaplasmosis and dirofilariasis, emphasising their possible role in the maintenance and transmission of these pathogens in certain regions of Croatia. These results underline the need for further research to better understand the epidemiological importance of red foxes in the spread of vector-borne diseases. Full article

We report the case of a 5-year-old boy from a Sri Lankan migrant family in Catania, Italy, diagnosed with a Dirofilaria repens infection in the spermatic cord. The child presented with pain and swelling in the left inguinal area. Initial evaluation suggested orchiepididymitis, which was treated unsuccessfully with amoxicillin/clavulanate and NSAIDs. As symptoms worsened, torsion of the Morgagni hydatid was considered. An exploratory surgery revealed a firm mass in the left spermatic cord. Histopathological examination of the excised lesion showed fragments of a helminth within a granulomatous inflammatory reaction. Subsequent PCR analysis detected D. repens DNA. The patient fully recovered after surgical excision of the mass. Given the increasing incidence of human dirofilariasis, D. repens should be considered in the differential diagnosis of unexplained subcutaneous or inguinal nodules, especially in patients with a relevant travel history. This case highlights the importance of accurate diagnosis to avoid unnecessary invasive procedures or prolonged antimicrobial therapies. It represents one of the youngest pediatric cases with genital involvement reported in Italy, a country that accounts for half of the cases in Europe. Full article

Heartworm disease (Dirofilaria immitis) is an important zoonotic infection of major clinical importance in dogs widespread, and transmitted by culicid vectors. Although D. immitis mostly affects dogs with an overall low incidence, some islands of the Atlantic archipelagos such as the island of Gran Canaria (Canary Islands, Spain) had one of the highest historical prevalence/seroprevalence values in dogs, cats and humans. Molecular tools allow us to perform species identification diagnosis, phylogeographic and population genetics analysis that can provide key information about the factors making the disease still a threat (uncover untreated range of hosts, putative origin, etc.). In this study, we have optimized primers to amplify mitochondrial (COI, 12S) and nuclear (ITS) molecular markers from adult D. immitis worms. The genetic diversity and structure of D. immitis at the global level is limited, especially when compared with results obtained for other species of the same genus, such as D. repens. New minor haplotypes in the mitochondrial COI marker have been identified from adult D. immitis worms from infected dogs from the hyperendemic island of Gran Canaria, suggesting that the disease may have originated locally or may have been introduced from the mainland in historical times and evolved in isolation. To obtain a more complete understanding of its evolutionary history, structure and genomic diversity, comparative studies using next-generation sequencing data from endemic areas are needed, which will help in the long term to implement monitoring and control measures in a given area and to better understand its global phylogeographic history. Full article

Purpose: Dirofilariasis is a zoonotic infectious disease caused by a species belonging to the Dirofilaria genus. Human dirofilariasis cases have increased in Europe in the last few decades. Dogs and wild canids represent the definitive hosts and principal reservoirs of Dirofilaria repens, while mosquito species are biological vectors. Humans act as accidental hosts, and clinical manifestations depend on the location of the worm in the organs or tissues. We described the first case of ocular dirofilariasis in the Aosta Valley region (Italy). Case description: a 62-year-old Italian woman complained of recurrent ocular redness, pain and discomfort, accompanied by itching and foreign body sensation in the right eye. The slit lamp biomicroscopic examination revealed conjunctival congestion on the temporal region of bulbar conjunctiva, and a long whitish vermiform mobile mass was detected under the conjunctiva. The anterior chamber showed no flare or cells in either eye, and the dilated fundus examination was normal. The worm was immediately surgically removed to prevent further migration, and was diagnosed morphologically and molecularly as D. repens. Following surgical removal, the symptoms resolved completely and rapidly, with no recurrence of ocular symptoms recorded during 12-month follow-up visits. Conclusions: Ocular dirofilariasis can lead to misdiagnosis due to its rare ocular manifestations, and it is considered an emergent zoonosis in European countries. Accurate diagnosis and control of ocular dirofilariasis by D. repens require a multidisciplinary approach under the One Health framework to effectively address this emergent zoonosis. Full article

Heartworm disease—caused by Dirofilaria immitis—is an emerging mosquito-borne zoonotic disease with potentially fatal outcomes in dogs. Due to factors such as climate change, animal importation, and animal transport, the prevalence of the infection has increased in countries in Central and Eastern Europe, where the parasite was not detected before. The first autochthonous case of D. immitis in dogs in Hungary was reported in 2009. This study assessed the prevalence of D. immitis infection and the associated risk factors in domestic dogs in Hungary. A total of 1071 blood samples were collected between March 2023 and February 2024 and were tested using Knott’s test, ELISA, and real-time PCR method. The countrywide prevalence of D. immitis was 17.0%, suggesting a continuous increase in the parasite’s spread compared to the previously reported 11.3% prevalence, with age and spending time outdoors being the main risk factors. These results highlight the ongoing need for preventive measures against heartworm disease. Full article

In June 2024, a 41 year-old woman presented to the infectious diseases outpatient clinic with a left inguinal mass progressing in size. The patient had previously been on vacation in Greece. When a tumor was initially suspected, the mass was surgically removed. Staining with Grocott methenamine silver and Alzian blue were inconspicuous, but histopathologic examination revealed a clear histiocytic demarcation, followed by a confirmation of the suspected diagnosis of dirofilariasis caused by Dirofilaria repens by PCR. Even though still a rare event in Austria, the number of human D. repens cases has been continuously increasing in recent years. This is partly due to the increased spread of the parasite due to climate change and globalization. Full article

Accurate rapid diagnostic tests (RDTs) are needed to diagnose lymphatic filariasis (LF) in global elimination programmes. We evaluated the performance of the new STANDARD Q Filariasis Antigen Test (QFAT) against the Bioline Filariasis Test Strip (FTS) for detecting W. bancrofti antigen (Ag) in laboratory conditions, using serum (n = 195) and plasma (n = 189) from LF-endemic areas (Samoa, American Samoa and Myanmar) and Australian negative controls (n = 46). The prior Ag status of endemic samples (54.9% Ag-positive) was determined by rapid test (ICT or FTS) or Og4C3 ELISA. The proportion of samples testing positive at 10 min was similar for QFAT (44.8%) and FTS (41.3%). Concordance between tests was 93.5% (kappa 0.87, n = 417) at 10 min, and it increased to 98.8% (kappa 0.98) at 24 h. The sensitivities of QFAT and FTS at 10 min compared to the prior results were 92% (95% CI 88.0–96.0) and 86% (95% CI 80.0–90.0), respectively, and they increased to 97% and 99% at 24 h. Specificity was 98% for QFAT and 99% for FTS at 10 min. Both tests showed evidence of cross-reaction with Dirofilaria repens and Onchocerca lupi but not with Acanthochilonema reconditum or Cercopithifilaria bainae. Under laboratory conditions, QFAT is a suitable alternative RDT to FTS. Full article

Dirofilaria immitis and Angiostrongylus vasorum are major parasitic nematodes of dogs. Many environmental and phenological changes have recently modified their geographic patterns in many countries; thus, this study has updated the distribution of D. immitis and A. vasorum in dog populations of selected regions of Central and Southern Italy. Also, collateral data on other endoparasites affecting the study population have been collected. Blood and fecal samples collected from 2000 dogs were tested using Knott’s test and copromicroscopy (i.e., Baermann’s and fecal flotation tests), respectively. Binomial logistic regression was performed to evaluate statistically significant associations between positivity for D. immitis and/or A. vasorum and potential risk factors. Overall, 35 (1.7%) and 62 (3.1%) dogs were positive for microfilariae of D. immitis and first stage larvae (L1) of A. vasorum, respectively, while 3 (0.1%) were co-infected by both nematodes. Microfilariae of Dirofilaria repens were found in 148 (7.4%) dogs, while at the flotation, eggs of Ancylostomatidae, Trichuris vulpis, and ascarids were found in the feces of 323 (16.5%), 249 (12.4%), and 172 (8.6%), dogs, respectively. Overall, 217 (10.8%) and 44 (2.2%) dogs were positive for eggs of Capillaria aerophila and Capillaria boehmi. The presence of cardiorespiratory clinical signs or non-specific signs, history of travel, and an age of >4 years old were significantly associated with positivity for D. immitis, while A. vasorum was significantly recorded in dogs with cardiorespiratory signs, or with a history of mollusk ingestion or permanent outdoor housing. These results confirm that D. immitis is enzootic in the investigated regions of Central and Southern Italy, even where it was rare/undetected until recently. Indeed, although some dogs positive for D. immitis had a history of travel in enzootic areas, the majority of them were never moved, indicating that they acquired the parasite in the region where they live. Additionally, A. vasorum is stably enzootic in the study areas, as also are other extraintestinal nematodes (i.e., D. repens and C. aerophila) that are more frequently detected today than in the past. A high level of vigilance and routine parasitological screening are necessary, considering the high prevalence of intestinal parasites in owned dogs that are also co-infected by respiratory parasites. The implementation of chemoprevention against D. immitis in dogs living in the examined area should be encouraged. Full article

Dirofilariosis, a mosquito-borne disease caused by Dirofilaria immitis and Dirofilaria repens, affects canids, felids and occasionally humans. Recent evidence suggests that D. immitis prevalence is rising in the canine populations in several areas of Brazil, even those historically considered to be non-endemic, highlighting the need for ongoing surveillance. However, prevalence studies are frequently based on inference from single diagnostic methods, and it is acknowledged that this may lead to biases and an underestimation of the disease situation. Thus, this cross-sectional study aimed to assess the prevalence of Dirofilaria spp. infection in dogs and cats across suburban and urban areas in Rio de Janeiro, Brazil. The investigation was conducted using a multi-diagnostic approach with binomial generalised linear models (GLMs) applied to investigate the association between the occurrence of infection and potential disease determinants. Blood samples from 497 dogs and 107 cats, collected at a veterinary mobile neutering unit, underwent parasitological, serological and molecular testing to detect Dirofilaria spp. infections. Among the dog samples, an overall 7.44% tested positive for D. immitis infection, while D. repens was not detected. In contrast, no cat samples tested positive for either parasite species. Prevalence was notably higher in suburban areas (14.47%) than in the urban area of Rio de Janeiro (6.17%) (p = 0.003). Dogs aged over two years had a higher risk of being infected (p < 0.001), while features such as breed, sex, size, coat type, use of macrocyclic lactones or access to outdoor spaces were not found to be predictive factors. This study reinforces the evidence that the prevalence of D. immitis is increasing in areas previously considered to have low prevalence or to be non-endemic. It also suggests that environmental and socioeconomic factors may play a key role in determining the current epidemiological status of this parasite. These findings highlight the need for increased monitoring in high-risk areas, targeted prevention and public awareness to address this emerging One Health concern. Full article