Dirofilaria immitis and Dirofilaria repens: Investigating the Prevalence of Zoonotic Parasites in Dogs and Humans in a Hyperenzootic Area.

The mosquito-borne zoonotic nematode parasites Dirofilaria immitis and Dirofilaria repens primarily affect dogs. In recent years, their distribution has expanded due to various factors influencing vector-borne pathogens. This study aimed to investigate the comparative prevalence of infection in dogs and humans within a hyperenzootic region of Europe, and to estimate the proportional relationship between infection prevalence in dogs and humans, within the concept of "One Health". To this end, 604 blood samples from dogs and 625 serum samples from humans living in the Thrace region of northeastern Greece were collected. The dog samples were examined for Dirofilaria spp. microfilariae using Kott's test and for D. immitis antigen using a commercial serological test. The human sera were analyzed for both parasites by Western blot. The overall prevalence of infection in dogs was 177 (29.3%), with 173 (28.6%) testing positive for D. immitis and 7 (1.2%) for D. repens, including 6 (1%) cases of mixed infection. Specific IgG antibodies were detected in 42 (6.7%) human samples, with 24 (3.8%) positive for D. immitis and 18 (2.9%) for D. repens. The infection proportion in humans was 23.4% of the corresponding canine infections, indicating a high risk of human infection in this hyperenzootic region.

[Clinical case of dirofiariosis in the practice of otorhinolaryngologist]. / Klinicheskii sluchai dirofilyarioza v praktike vracha-otorinolaringologa.

The article presents the clinical case of a young woman with the dirofilariosis of the nose slope on the right side. This disease is quite rare, and therefore there is a difficulty in setting the correct one. This case is a professional interest both for young doctors and for experienced specialists. Specialists,will be able, if necessary, to correctly diagnose and effectively treat this disease analyzing the given clinical example.

A case of human Dirofilaria repens in Rome, Italy: A clinical and radiological challenge.

Human subcutaneous dirofilariasis caused by Dirofilaria repens is a vectorborne zoonotic disease mostly transmitted from dogs to humans through a mosquito's blood meal. Heartworms replication is amplified by the climate change, the increase of the range of suitable vectors, the facilitation of pet travel and the high rate of undiagnosed dirofilariasis in dogs. We describe a case of a young Romanian woman, resident in Rome for 18 years, that came to our attention for the appearance for five months of a subcutaneous nodule in the left arm. The patient reported that she first felt an insect bite, after which she noticed the onset of an erythematous and itchy wheal in the same skin area, turned into a subcutaneous nodule within a few weeks. The ultrasound examination showed a hypoechoic subcutaneous formation of 1,2 cm in diameter, containing a ribbon-like structure made up of hyperechoic parallel double lines, reminiscent of a warm. Based on this suspicion, we opted for the surgical radicalization of the lesion. The histological examination confirmed the radiological hypothesis of a warm-like foreign body morphologically compatible with Dirofilaria repens. Our experience shows how a clinical nonspecific skin nodular lesion may conceal an unexpected and unsettling diagnosis of subcutaneous Dirofilaria repens.

New cases of human dirofilariosis on the Balkan Peninsula - "Masked intruders" uncovered by a surgeon.

Dirofilaria spp. nematodes are accidental parasites of humans causing mild to serious, superficial or visceral infections. Superficial dirofilariosis is rather common in Europe and is typically manifested as subcutaneous form. Herein we report 46 new cases of human dirofilariosis (19 patients with subcutaneous, 18 patients with ocular, 4 patients wih genital, 2 patients with submucosal, 2 patients with pulmonary and 1 patient with intramuscular form of infection) that were recorded from the beginning of 2015 to May 2021 on the Balkan Peninsula with a goal to update the prevalence of this parasitosis and point out potential problems in diagnosis and treatment. Besides, given the high possibility of misinterpretation as tumor, our second aim was to encourage the inclusion of this pathogen in the differential diagnosis of subcutaneous nodules. Although quite common forms, subcutaneous and ocular dirofilariosis can be very often misdiagnosed in clinical practice due to the absence of specific clinical manifestations. Therefore, raising awareness of clinicians about this zoonosis is needed as well as closer collaboration between physicians and veterinarians.

Human dirofilariosis in the 21st century: A scoping review of clinical cases reported in the literature.

Human dirofilariosis is a clinical entity caused by infection with nematode species of the genus Dirofilaria. The traditional picture depicts the disease as a sporadic event associated with the presence of a single immature worm causing a nodular lesion. With the aim to reassess this paradigm, establishing a more accurate picture of the disease and homogenize criteria, a scoping review was conducted by searching, screening and analysing published clinical cases of human dirofilariosis worldwide during the 21st century. After extracting data from 305 publications containing 576 case reports, results showed that human dirofilariosis is currently caused by five Dirofilaria species (mainly D. repens). Maturation was not uncommon, since 42.95% of the parasites recovered were described as mature worms, most of them females, 26.42% of which contained micofilariae in the uterus. Moreover, six microfilaremic cases have been described. The predominant clinical manifestation was the presence of a worm encapsulated within a nodule, but there is a considerable variety of accompanying symptoms depending on anatomical location and type of dirofilariosis. Parasites/nodules were found in 71 different anatomical locations, being the traditional nomenclature of human dirofilariosis unable to properly cover this complex situation. Delay in seeking medical assistance (patient perception) and the frequency of wrong clinical suspicions (doctor knowledge), strongly influenced clinical management. The initial suspicion in cases of subcutaneous and pulmonary dirofilariosis is predominantly a tumour, while in the ocular dirofilariosis a parasite (but not directly Dirofilaria) is mostly suspected. Surgery is usually applied, regardless of the use of non-invasive techniques during preoperative management and although its use is still limited, molecular approach is the most accurate technique to establish a species-level diagnosis. Accurate epidemiological, parasitological and clinical information while handling and reporting human clinical cases is a need for physicians and researchers to improve and standardize the clinical management of human dirofilariosis.

Dirofilaria immitis Could Be a Risk Factor for the Development of Allergic Diseases in Humans.

The Canary Islands are hyperendemic for canine heartworm and the risk of zoonotic infection is high. Additionally, there is evidence of development of allergies due to nematode infections in animals and humans. Since the population of the Canary Islands presents high prevalence of allergic comorbidities, and previous studies have shown a possible relationship between allergies and seropositivity to heartworm, the aim was to evaluate whether exposure to heartworm may contribute to the development of allergies in the human population. First, an epidemiological study was conducted on 248 owners of dogs with/without heartworm infection in the Canary Islands. Secondly, a serological analysis of the presence of total IgE and specific IgE against heartworm was conducted in 66 samples of inhabitants of the Canary Islands. The survey showed that allergic owners had heartworm-positive dogs more frequently (p < 0.01). Of the analyzed human samples, 43.9% were seropositive to heartworm and Wolbachia. Total IgE concentrations were increased in 34.5% seropositive samples and 8.1% seronegative samples. Specific IgE against heartworm was only found in human seropositive samples (17.2%). Contact with heartworm may be a risk factor for the development of allergic diseases, although further studies to elucidate the relationship between heartworm and allergies should be carried out.

Human seroprevalence data indicate other factors than climatic conditions influencing dirofilariosis transmission in the Russian Federation.

The species of the genus Dirofilaria are filarial parasites causing zoonotic infections in humans with an increasing incidence in temperate and tropical areas of the world. Due to its classification as a vector-borne disease, the most important factors influencing dirofilariosis transmission are those related to climate, such as temperature and humidity. However, other factors linked with human behaviour can influence the distribution of the parasite. Although the Russian Federation could be considered as a non-suitable area for Dirofilaria spp. transmission due to its climatic conditions, one third of the human cases of dirofilariosis have been declared in this country. Here, seroepidemiological data on human dirofilariosis for five different regions distributed throughout the Russian Federation (Rostov, Moscow, Ekaterinburg, Yakutia and Khabarovsk) were obtained. A total of 940 serum samples from totally random donors living in these areas were analysed by enzyme-linked immunosorbent assay for the detection of anti-Dirofilaria immitis immunoglobulin G antibodies. Similar seroprevalence data ranging from 3.41% in Yakutia to 6.95% in Khabarovsk, with no significant correlation with climatic data of yearly average temperature and rainfall from these regions were found. These results suggest that other factors probably related to human behaviour, and not only climatic conditions, might be facilitating the spread of human dirofilariosis in these areas.

Current Situation of the Presence of Dirofilaria immitis in Dogs and Humans in Bucaramanga, Colombia.

The cardiopulmonary dirofilariosis caused by Dirofilaria immitis, is a vector-borne infection, which can be transmitted to humans. The main hosts are both domestic and wild canids. This species mainly occurs in tropical and subtropical climates, and temperature and humidity are the main factors that favor the presence and proliferation of culicid mosquitoes as vectors of the disease. There are few reports of cardiopulmonary dirofilariosis in dogs and humans in Colombia, a region with favorable climatic conditions which favors the presence of mosquitoes that act as vectors of the disease. Therefore, this study aimed to examine its current prevalence in dogs and the risk of human exposure to the disease in Bucaramanga, one of the most populated areas in Colombia located at the center of the country. Furthermore, its demographic and environmental characteristics could be useful as a study model for other similar locations and neighboring countries. Serum samples from 351 dogs and 506 humans from the Bucaramanga Metropolitan area were analyzed. All dog samples were analyzed by Knott's technique and tested with a commercial immunochromatographic to detect the presence of circulating antigens of D. immitis. Human samples were analyzed using a non-commercial ELISA test kit to detect IgG against the somatic antigens of adult D. immitis and Wolbachia. Positive results were further confirmed using western blot analysis. Thirty-eight dogs tested positive with a overall prevalence of 10.82%. Of these dogs, 18 showed D. immitis microfilariae, being 5.12% of the total population. The overall seroprevalence in humans was 6.71%; seroprevalence was significantly higher in individuals aged 16-34 years-old and in women than in men. To our knowledge, this study describes seropositivity to D. immitis for the first time in a Colombian human population located in the same area as that of dogs infected with D. immitis, which represents a potential threat to public health. In humans, age and gender can be considered risk factors for exposure to D. immitis.

Prevalence of canine and human dirofilariosis in Puebla, Mexico.

The objective of this work was to determine the risk of exposure to Dirofilaria immitis in the stray dog population and people living in the metropolitan area of Puebla City, Mexico, using serologic methods. A total of 283 blood salmples were collected from dogs and 254 salmples from people. The canine samples were analyzed using a commercial kit to detect D. immitis antigens and the Knott test to detect microfilariae. Human samples were analyzed by ELISAs to detect antibodies against D. immitis and Wolbachia anti-WSP, as well as Western blot to identify specific bands of the parasite in the adult antigenic extract of D. immitis. Positive results were represented on a GIS map that included layers with geoenvironmental information relevant to parasite transmission in the study area. The prevalence of D. immitis in the canine stray population was 2.12 %, with positive cases found in individuals aged 1-10 years. Human seroprevalence was established at 5.11 %, with women and men similarly affected. By age, a significantly higher seroprevalence was observed in younger individuals (<18 years) than in the rest of the population. The geolocation of the results showed that positive cases were found in the environment (within 2 km) of potentially favorable areas for mosquito breeding. The importance of human influence in the creation and maintenance of favorable conditions for the transmission of canine and human dirofilariosis within an urban area is highlighted, both by the lack of environmental sanitation and by the absence of measures to limit or eliminate the canine reservoir population.

Subcutaneous Human Dirofilariosis By D. Repens In South Italy: A Case Report.

Human dirofilariosis is a zoonosis caused by different Dirofilaria species: D. repens, D. immitis, D. tenuis and D. ursi, thin nematodes belonging to the Onchocercidae family, whose larval stages are generally found in the natural (felines and canids) or accidental (human) definitive host. In Europe, human infection is rare, even in areas considered endemic such as Spain or Italy. In this paper we describe the case of an 82-year-old woman living in Modugno (Bari municipality), who came to our observation for a subcutaneous nodule on her right thigh that had appeared in the previous two weeks and gradually became necrotic. The woman lived in an apartment with a dog. An adult worm, white, thin, about 140 mm long, came out of the necrotic area spontaneously. After microscopic examination, the worm was identified as D. repens. In Apulia, a South-Italy region, human dirofilariosis is a rare disease and since 1885 only 11 cases have been reported. In recent years we have witnessed an increase in the number of diseases transmitted by vectors at all latitudes, and in our region an increase in the Aedes albopticus population has been reported, so it is reasonable to expect an increase in dirofilariosis cases in humans.

Human dirofilariosis of buccal mucosa - First molecularly confirmed case and literature review.

When presented in unusual manner, human dirofilariosis is hard to recognize and often leads to misdiagnosis and unjustified use of various medications. Herein, we report a rare case of Dirofilaria infection localized in buccal mucosa. A 45-year-old male, residing in the Central Serbia, developed striking edema of buccal mucosa followed by leucocytosis, with both neutrophylia and eosinophylia. Thirty days after first symptoms occurred, nodule was formed along the lateral edge of right maxilla. Therefore, patient underwent surgical extirpation and subsequent histopathological analysis of the specimen revealed the presence of a nematode. Based on morphological characteristics of detected parasite, the diagnosis of submucosal Dirofilaria repens-like infection was made. The diagnosis was confirmed, being the first case in the world analyzed by molecular methods. So far, only 13 such cases have been reported worldwide and our paper brings attention to rare form of this zoonosis and updates the data about human dirofilariosis in buccal mucosa.

[Dirofilariasis in the head and neck region. Case report]. / A dirofilariosis ­ fonalféreg-fertozés ­ ritka esete fej-nyak sebészeti területen.

Dirofilariasis refers to an infection caused by a specific parasitic roundworm. Dirofilaria repens - transmitted by mosquito bites - accounts for most human cases. The parasite forms a subcutaneous mass called cutaneous dirofilariasis near the original site of intrusion. The incidence of human infections shows an increasing tendency. We report a case of a 35-year-old woman presenting with three-week history of a painful swelling in the temporal region. The initial diagnostic work-up revealed a roundworm embedded in the subcutaneous fat tissue and temporal muscle. Differential diagnosis included erysipelas, herpes zoster, temporal arteritis. The final diagnosis of helminthiasis was established by ultrasound examination. A multidisciplinary consultation including infectious diseases specialist suggested surgical removal of the lesion. The microbiological examination of the specimen confirmed the presence of a female Dirofilaria repens. Orv Hetil. 2018; 159(45): 1844-1847.

Seroepidemiological survey of human exposure to Dirofilaria spp. in Romania and Moldova.

The present study aimed to evaluate the extent of Dirofilaria immitis and D. repens exposure in humans from eastern and southern areas of Romania and central Moldova by serological methods. The serological screening was performed on a total of 450 serum samples (187 from Romania and 263 from Moldova). The sera were collected using a convenience sampling with the help of physicians from the hospitals of the study areas. All samples were analysed by a non-commercial ELISA test for the detection of IgG antibodies against adult somatic antigens of D. immitis and D. repens. The results showed a total of 49 (10.9%; 95% CI = 8.3-14.1%) individuals from Romania and Moldova with a positive response to IgG antibodies against both adult somatic antigens of D. immitis and D. repens. Specifically, 48 (10.7%; 95% CI = 8.0-14.0%) patients were positive for IgG-antibodies against adult somatic antigens of D. immitis, one (0.2%; 95% CI = 0.4-1.2%) against D. repens antigens, and four (0.9%; 95% CI = 0.4-3.3%). were positive for antigens of both parasites. At country level, out of 187 samples from Romania, 13 (6.9%; 95% CI = 4.1-11.5%) were positive for anti-D. immitis IgG with high exposure in the southern part of the country (Bucharest). Of the 263 people from Moldova, 36 (13.7%; 95% CI = 10.0-18.4%) were positive for D. immitis antigens from which three (1.1%, 95% CI = 0.4-3.3%) were positive for the antibodies against antigens of both parasites. Only one sample was found positive for anti-D. repens IgG. Positive IgG-ELISA results were confirmed by Western blot analysis. In addition, for further confirmation, a complementary ELISA was performed for anti-WSP IgG antibodies against Wolbachia endosymbionts. Our findings showed a noticeable exposure of humans from Romania and Moldova to Dirofilaria parasites. Serology can be useful for indicating exposure to Dirofilaria spp. in a healthy population in order to obtain useful data on the epidemiological scenario of human dirofilariosis in Eastern Europe.

Human Dirofilaria repens infections diagnosed in Slovakia in the last 10 years (2007-2017).

Human dirofilariosis is currently considered to be an emerging zoonosis of Central Europe with climate change and globalization playing a key role in its spreading. Additionally, the occurrence of Dirofilaria spp. is strongly subject to a certain number of microfilaremic dogs and the presence of the mosquito vectors. Both conditions are fulfilled in Slovakia. The first human case of autochthonous dirofilariosis in Slovakia was diagnosed in 2007, 2 years after the infection had been observed in the Slovak dog population. Since then, a total of 12 human cases caused by Dirofilaria repens have been registered at the Institute of Parasitology, Slovak Academy of Sciences, 7 subcutaneous, 4 ocular and 1 pulmonary; however, it is likely that some cases remain undiagnosed, seeing that this infection is still missed by physicians. Of the patients 9 were male and 3 were female and their age varied between 15 and 72 years (mean 49 years). The majority of those affected came from the southern regions of the country, bordering Austria and Hungary, which are considered to be endemic areas for canine dirofilariosis. In this paper all published and unpublished cases are reviewed, with a special emphasis on the rare pulmonary form of D. repens infection.