Candidatus Dirofilaria hongkongensis as Causative Agent of Human Ocular Filariosis after Travel to India

We report a human case of ocular Dirofilaria infection in a traveler returning to Austria from India. Analysis of mitochondrial sequences identified the worm as Candidatus Dirofilaria hongkongensis, a close relative of Dirofilaria repens, which was only recently described in Hong Kong and proposed as a new species.

Leishmania infantum, Dirofilaria spp. and other endoparasite infections in kennel dogs in central Italy

Prevalence and risk factors of Leishmania infantum, Dirofilaria spp. and other potentially zoonotic or canine-specific endoparasite infections were assessed in 639 kennel dogs from central Italy. To this end, individual blood and fecal samples were examined using parasitological, immunological and molecular techniques. The presence of compatible clinical pictures, as well as age and gender were considered as putative risks factors. To evaluate risk factors, multivariable analysis with logistic regression and univariable analysis with a Chi square test and a Fischer's exact test were performed. Overall, 52.6% of dogs (95% CI 48.6-56.5) were found positive, while 39.6% of dogs (95% CI 35.8-43.5) were infected by potentially zoonotic species. Leishmania infantum and Dirofilaria repens showed prevalences of 2.5% (95% CI 1.5-4.1) and 2.8% (95% CI 1.7-4.5), respectively. The prevalence of cardiorespiratory parasites was 7.8% (95% CI 5.9-10.3) and included the species Angiostrongylus vasorum, Eucoleus aerophilus, Eucoleus boehmi and D. immitis; the latter showed a prevalence of 0.2% (95% CI 0.001-1). Intestinal parasites were significantly prevalent (38.8%, 95% CI 35-42.7) and they consisted mainly of species of major zoonotic concern, including ancylostomatids, Toxocara canis, Giardia duodenalis, Dipylidium caninum, Taeniidae, Strongyloides stercoralis and Cryptosporidium parvum. Endoparasites were significantly prevalent in clinically suspected dogs. Leishmania infantum and cardiorespiratory nematodes were prevalent in older dogs, while intestinal parasites were prevalent in younger dogs. Results show high dog and public health risks in kennels in central Italy, and suggest the need for more effective control measures.

DIROFILARIASIS: CURRENT ASPECTS OF STUDIES

The review touches upon the main directions and some of the most important results of an investigation of dirofilariasis the species of the genus Dirofilaria, their spread, and hosts. It describes cases of human infection with Candidatus Dirofilaria hongkongensis, a study of the prevalence of filariasis using a geographic information system, data on the contamination of Dirofilaria in Europe, and current views on the endosymbiotic relations of Dirofilaria with the Wolbachia bacterium.

[BLOODSUCKING MOSQUITOES (DIPTERA: CULICIDAE) IN, THE TULA REGION ARE POTENTIAL VECTORS OF DIROFILARIAS]

Bloodsucking mosquitoes were collected in Tula and its Region in May to August 2013-2014. The fauna included 17 species from 5 genera in the subfamily Culicinae and Anopheles maculipennis complex in the subsystem Anophelinae. Ochlerotatus cantans was a dominant species in the collections. The dominant species also included Aedes einereus, Ae. vexans, Ae. geniculatus, Och. diantaeus, Och. intrudens, Och. Cataphylla, and Culex pipiens. The possible value of different mosquito species Dirofilaria repens and D. immitis as vectors of dirofilarasis was discussed.

Genetic diversity of Dirofilaria spp. isolated from subcutaneous and ocular lesions of human patients in Ukraine

This short communication describes the phylogenetic analysis of 48 Dirofilaria worms isolated from human patients in Ukraine. 102 cases were both of subcutaneous (47; 46.1%) and ocular (54; 52.9%) locations. Worms from 44 patients (15 subcutaneous and 29 ocular) were subjected to DNA extraction and amplification of a specific fragment of the 12S rRNA subunit, and sequences were used for phylogenetic analysis. Results showed that 13.8% of the ocular cases analyzed at molecular level were caused by Dirofilaria immitis. Very few cases of ocular human dirofilariosis due to D. immitis have been described in the literature to date, majority of them attributed to Dirofilaria repens. Our results show that ocular dirofilariosis cannot be excluded in areas of low endemicity for D. repens were D. immitis is also present.

[Entomological monitoring of an area to assess Dirofilaria transmission risk]

As the basis for entomological monitoring, the authors first propose to investigate the structure of a season of D. repens invasion transmission in the carrier in relation to the ambient temperature, such as onset of a transmission season, terminaton of mosquito infection, the number of invasion circulations. A calculating procedure has been developed. It is shown that there is a need for entomological monitoring of each specific area irrespective of the latitude to study a risk for local dirofilariasis cases.

[Results of studies of human dirofilariasis in Russia]

Human dirofilariasis is a pressing health problem in Russia. By 2014, there have been as many as 850 Dirofilaria repens-infested people living in 42 subjects of the Russian Federation. One of the favorable factors for circulation and spread of invasion is a temperature of above +20-24 degrees C; when the latter is maintained during at least 20 days there may be 1.-1.5 circulations of invasion in the carrier and a 2.8-fold increase in transmission intensity. The border ofa dirofilariasis area with a temperate climate is southward to 58 degrees N in European Russia and West Siberia and southward to 50 degrees N in the Far East. The conditions in the human body have been found to be more favorable for the development of Dirofilaria than considered before and allow the helminth to achieve sexual maturity and to propagate. If man has microfilaremia, he may be a source of invasion. It is necessary to examine venous blood by the enrichment method and, if possible, polymerase chain reaction and enzyme immunoassay, which make it possible to establish a diagnosis in occult invasion and to identify a pathogen species.

[Procedures for species identification of the nematodes belonging to Dirofilaria genus present in the clinical material isolated from humans]

Procedures for DNA extraction and amplification were modified to allow identification of Dirofilaria nematodes surgically removed from human tissues. Worm samples stored in: ethanol (24 weeks), formalin (46 weeks) or paraffin blocks (25weeks) were examined. Fragments of two ribosomal DNA regions (5.8S-ITS2-28S, 5SrRNA) and mitochondrial cytochrome oxidase subunit I gene were used as diagnostic markers. The highest PCR sensitivity was observed for DNA obtained from the worm preserved in ethanol, while the nucleic acid extracted form the parasite stored in formalin yielded the lowest PCR sensitivity. DNA extraction from the parasite preserved in formalin was more time consuming than DNA extraction from the remaining samples. Furthermore, the amplification of DNA isolated from the formaldehyde preserved worm allowed for identification of the parasite species only when the mitochondrial marker was used in Real Time PCR, and the amount of the obtained product was close to the detection limit. Species identification of the worms stored in the paraffin block and in ethanol was possible with both traditional and Real Time PCR. All analyzed worms were identified as D. repens which confirmed the species identification based on morphological features. The results show that molecular methods are relatively simple to use and suitable for identification ofDirofilaria sp. nematodes present in clinical material. Formalin is not suitable for storing material intended for molecular tests.

Several cases of dirofilariosis accidentally diagnosed in dogs from Poland, including two PCR positive Dirofilaria repens cases

The aim of the present study was a description of several microfilaremia cases diagnosed in dogs from Poland. The study was conducted on cytological samples of pathologic masses and peripheral blood smears taken for diagnostic purposes from dogs showing a various clinical findings. The presence of the parasites in tissue samples was observed in 8 dogs, additionally, in 2 of these dogs PCR analysis of blood samples revealed the presence of D. repens DNA.

[Human dirofilariasis in the Tula region]

The paper describes cases of dirofilariasis in the residents of Tula and the Tula Region. One of the cases does not fit into the traditional concepts. On excising a tumor in an adolescent, two live actively moving nonencapsulated helminths: a male and a female Dirofilaria repens worms were removed, which were identified at the parasitology laboratory, Center of Hygiene and Epidemiology in the Tula Region.

Human dirofilariosis in the Slovak Republic - a case report

The spread of dirofilariosis, as a newly emerging zoonosis, due to global changes has been documented in several Central European countries. In Slovakia, the first autochthonous case of dirofilariosis was recorded in dogs in 2005. The first case of human subcutaneous dirofilariosis caused by Dirofilaria repens was diagnosed in a 60- year-old patient from an area of western Slovakia. We report another case of dirofilariosis in a 37-year-old woman living in the same area of south-western Slovakia. The infection manifested as a painful, inflamed nodule on the back of the left hand, containing an adult parasite. Morphological analysis aroused suspicion of the presence of a filarial worm belonging to the genus Dirofilaria. Subsequent PCR analysis of the DNA identified the parasite as Dirofilaria repens. After removal of the parasite, the subcutaneous nodule completely resolved and the patient was successfully cured.

[Biological characteristics of the causative agent of dirofilariasis in dogs in the Rostov Region]

This paper assesses the trends in the identification of different Dirofilaria species in the Rostov Region and comparatively analyzes the general clinical and biochemical blood indices in dogs with and Without helminthism. Seasonal variations in the invasion and species composition of the parasite have been established. At present, there is a gradual replacement of the species Dirofilaria repens by Dirofilaria immitis in this area. The blood general clinical and biochemical studies in ill dogs with dirofilariasis have ascertained that the pathogenic action on the animals is more pronounced with Dirofilaria immitis being parasitizing and with the mixed invasion of two helminth species.

[The first foci of dirofilariosis of dogs evoked by Dirofilaria repens Railliet et Henry, 1911 in central Poland]

Dirofilariosis is caused by nematodes Dirofilaria repens Railliet et Henry, 1911. This parasitosis is widely distributed in south Europe among dogs, cats and wild carnivorous. It occurs also in Asia and Africa. Adult nematodes D. repens locate in nodules, in subcutaneous or intramuscular connective tissue of dogs. The mosquitoes from genera Anopheles, Aedes and Culex are the intermediate hosts and vectors of mentioned parasites. The finding of 6 adult nematodes belonging to the species D. repens in scrotum under tunica vaginalis, during the castration of the dog, which has never been abroad, tended us to undertake presented studies. In August and September of 2009, 64 genuine dogs age from 1.5 to 12 years originated from 3 kennels in central Poland were examined. Dogs did not show any pathological symptoms of infection. Blood samples were examined for the presence of infection and a number of microfilariae. Species of microfilariae was determined after staining on the basis of morphological characters. In examined blood samples from dogs microfilariae belonging to the species Dirofilaria repens were found. Mean prevalence of infection in all examined kennels was 37.5% and mean intensity 32 microfilariae in 30 microl of blood. Microfilariae of D. immitis were not found in any examined blood samples. The results of presented studies show that native dirofilariosis of dogs caused by D. repens is common in central Poland. The result of our investigations lets us suppose, that the range of occurrence of D. repens will spread significantly towards north Europe.

[Human subcutaneous dirofilariosis due to Dirofilaria repens. A case diagnosed in Strasbourg, France]

We report a case of human dirofilariosis in a 35 year-old man living in Alsace (North-East France), who presented a subcutaneous nodule of the left cheek, strongly simulating an epidermic cyst. Surgical excision and histopathological examination unexpectedly established the diagnosis by the presence of nematode worm sections identified as Dirofilaria (Nochtiella) repens. This patient living in a rural area of Strasbourg spent one week in Toulon, Southern France. This new observation of cutaneous dirofilariosis constitutes the third Alsatian case described in literature, and emphasizes the presence of this parasitic disease in Southern France.

Discrimination between six species of canine microfilariae by a single polymerase chain reaction

Canine dirofilariasis caused by Dirofilaria immitis is usually diagnosed by specific antigen testing and/or identification of microfilariae. However, D. immitis and at least six other filariae can produce canine microfilaremias with negative heartworm antigen tests. Discriminating these can be of clinical importance. To resolve discordant diagnoses by two diagnostic laboratories in an antigen-negative, microfilaremic dog recently imported into the US from Europe we developed a simple molecular method of identifying different microfilariae, and subsequently validated our method against six different filariae known to infect dogs by amplifying ribosomal DNA spacer sequences by polymerase chain reaction using common and species-specific primers, and sequencing the products to confirm the genotype of the filariae. We identified the filaria in this dog as D. repens. This is the first case of D. repens infection in the United States. Additionally, we examined microfilariae from five additional antigen-negative, microfilaremic dogs and successfully identified the infecting parasite in each case. Our diagnoses differed from the initial morphological diagnosis in three of these cases, demonstrating the inaccuracy of morphological diagnosis. In each case, microfilariae identified morphologically as A. reconditum were identified as D. immitis by molecular methods. Finally, we demonstrated that our PCR method should amplify DNA from at least two additional filariae (Onchocerca and Mansonella), suggesting that this method may be suitable for genotyping all members of the family Onchocercidae.

Subtenons infection by dirofilaria repens

Zoonotic filariasis caused by Dirofilaria repens, a parasite of carnivores occurs mainly in countries surrounding Mediterranean region. The infection occurs in and around eye among animal handlers through vector transmission. We are reporting a case of human Dirofilariasis affecting subtenons region in a 63 year-old woman from Coimbatore, South India. The purpose of this article is to review the clinical course and management of ocular Dirofilariasis.

Detection and differentiation of filarial parasites by universal primers and polymerase chain reaction-restriction fragment length polymorphism analysis

Filarial nematode parasites are a serious cause of morbidity in humans and animals. Identification of filarial infection using traditional morphologic criteria can be difficult and lead to misdiagnosis. We report on a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-based method to detect and differentiate a broad range of filarial species in a single PCR. The first internal transcribed spacer 1 (ITS1) along with the flanking 18S and 5.8S ribosomal DNA (rDNA) were isolated and cloned from Wuchereria bancrofti, Brugia malayi, and Brugia pahangi. Sequence analysis identified conserved sites in the 18S and 5.8S rDNA sequence that could be used as universal priming sites to generate ITS1-distinctive PCR products that were useful for distinguishing filariae at the genus level. The addition of a digestion of the ITS1 PCR product with the restriction endonuclease Ase I generated a fragment profile that allowed differentiation down to the species level for W. bancrofti, B. malayi, B. pahangi, Dirofilaria immitis, and D. repens. The PCR-RFLP of ITS1 rDNA will be useful in diagnosing and differentiating filarial parasites in human, animal reservoir hosts, and mosquito vectors in disease-endemic areas.

Dog filariosis in the Lazio region (Central Italy): first report on the presence of Dirofilaria repens

Background

Epidemiological investigations were carried out in the Lazio Region to assess the status of canine filariosis and to evaluate the actual risk for veterinary and medical public health.

Methods

Since August 2001 to June 2003, a total of 972 canine blood samples, collected in public kennels and from private owners animals of the 5 Provinces of the Region, were tested. The presence of filarial parasites was evaluated by microscopy and bio-molecular techniques; the species identification was performed by means of the same diagnostic tools.

Results

A total of 17/972 (1.75%; 95%CI 1.06%–2.85%) blood samples were parasitized by D. repens,13 out them drawn by dogs resident in the Province of Roma, and 4 in the other provinces. Multivariate analysis was performed in order to evaluate the association between filariosis and risk factors. The origin from coastal territories seems to be a significant risk factor to acquire the infection.

Conclusion

This is the first report of canine filariosis in the Lazio Region, where D. repens was before reported only in foxes. The risk of human zoonotic infection is stressed, and the absence of other filarial species is discussed

First finding of Dirofilaria repens in a natural population of Aedes albopictus

The invasive mosquito Aedes albopictus (Skuse) (Diptera: Culicidae) has become widespread in Italy during the past decade. Also Italy has foci of canine filariasis caused by Dirofilaria (Spirurida: Onchocercidae), due to subcutaneous D. repens Railliet & Henry as well as the dog heartworm D. immitis (Leidy) transmitted by various vector mosquitoes (Diptera: Culicidae). In 2002, at Fiumicino, west of Rome (Lazio Region), 17% of dogs were found to have D. repens microfilariae in peripheral blood. To evaluate the role of Ae. albopictus as a vector of Dirofilaria in this area, female mosquitoes were collected daily, June-October 2002, landing on dog or human bait in a rural house at Focene. Mosquitoes were maintained at 27 degrees C and 70% RH for 6 days, to allow development or purging of filaria larvae, then identified and frozen for subsequent molecular assay with filaria-specific ribosomal S2-S16 primers. To distinguish specimens harbouring infective L3 Dirofilaria larvae, DNA was extracted separately from the mosquito abdomen and head-thorax. Dirofilaria species were identified by sequencing, confirmed by polymerase chain reaction of positive specimens using primers specific for D. immitis and D. repens. Dirofilaria DNA was detected in 3/154 (2%) of Ae. albopictus females examined: D. repens DNA in head-thorax and abdomen of one collected 27th July; D. immitis in the abdomen of one collected 24th September; DNA of both D. immitis and D. repens in the head-thorax of one collected 11th October 2002. Thus Ae. albopictus is a potential vector of both Dirofilarias in Italy, representing risks for veterinary and human health.

Intra-oral Dirofilaria repens infection: report of seven cases

Cutaneous dirofilariasis usually affects animals such as cats and dogs which are known to be the natural host of Dirofilaria. Dirofilariasis displays a worldwide distribution. Certain geographic regions account for the majority of reported cases. South-eastern United States, Australia and Europe have been identified as endemic regions (1, 2). However, new endemic areas are arising with increased awareness in African and Asian regions. Out of about 40 different species of Dirofilaria only a few species are commonly known to infect man, namely Dirofilaria immitus, D. tenices and D. repens. Human infection occurs when a human becomes a blood meal of an infected arthropod vector and on accidental entering of the worm. Rarely this zoonotic infection affects the oral mucosa (3). Man is the dead end of this parasite. Since the human body is an abnormal environment for the parasite, the development of the larvae is inhibited by means of retardation of sexual maturity. Lesions are presented as single non-tender subcutaneous nodules, and most patients are asymptomatic. Diagnosis is established by H&E sections prepared from excised nodules. In a majority of the cases, only a single worm either a male or a female could be identified. The worm is usually dead and degenerated with a massive inflammatory cell infiltration. Seven new cases presented as intra-oral nodules with their clinicopathological correlation are discussed.

Human dirofilariasis of the buccal mucosa: a case report

Human dirofilariasis is a helminthic zoonosis that is common in some parts of the world. A sporadic case of dirofilariasis affecting the buccal mucosa has been reported in a non-endemic area of southern China. Clinical findings, diagnosis, pathogenesis and management are discussed. This is the fourth case of human dirofilariasis involving the oral mucosa reported in world literature.

Genotypic assignment of infection by Dirofilaria repens

Dirofilariasis is a parasitic disease, which if treated inappropriately due to misdiagnosis, can cause unwanted complications particularly when the infection is located in the breast. The numerous obstacles that can cause misdiagnosis of dirofilariases by standard morphological procedures prompted the development of a Dirofilaria repens-specific direct polymerase chain reaction (PCR)-based diagnostic approach using freshly infected dog blood. Reliable amplification of nematode DNA from formalin-fixed infected human specimens by this method is only possible from relatively fresh biological material, preserved in the fixative for up to 20 days. We report here our first case of dirofilariasis since the development of PCR genotyping, where the pathogen was morphologically unrecognizable and the diagnosis was based exclusively on DNA amplification. We complete our methodological contribution to the clinical laboratory diagnosis of dirofilariasis by presenting two more cases, where the primary genotypic assignment of infection by D. repens was further confirmed by conventional morphological means.

Histochemical differentiation of Dirofilaria immitis, Dirofilaria repens and Acanthocheilonema dracunculoides microfilariae by staining with a commercial kit, Leucognost-SP

The diagnosis of canine heartworm infection is based upon the presence of circulating Dirofilaria immitis microfilariae or on techniques for the detection of serum antibodies or antigens. In the first of these, discrimination between D. immitis, D. repens and Acanthocheilonema dracunculoides microfilariae is based upon the acid phosphatase histochemical stain. In this paper, we propose an alternative technique for histochemical staining using a commercial kit test of naphthol-AS-OL (Leucognost-SP). This offers the advantages of speed and simplicity as compared to the standard Barka procedure.

Human dirofilariasis due to Dirofilaria (Nochtiella) repens: an update of world literature from 1995 to 2000

Following on from their review of 1995 (Pampiglione et al.), the authors present an update of human cases of dirofilariasis due to Dirofilaria (Nochtiella) repens (Nematoda, Filarioidea, Onchocercidae) reported in the world literature. Cases of the parasitosis published from 1995 to 2000 are reported country by country. The essential data are presented in tabular form and the clinical, parasitological, histopathological, epidemiological features are analysed. 372 new cases spread over 25 countries are thus added to the list published in 1995. The countries most affected are Italy, Sri Lanka, some republics of the ex-Soviet Union. The age of the patients varied from 4 months to 100 years, the majority being in their 40s. There was virtually no difference in incidence between sexes. The parasite appeared most frequently in the upper half of the body, particularly in the head and ocular region and also in the upper limbs. Cases of visceral involvement are also reported. Of the various forms of human dirofilariasis, that due to D. (N.) repens is confirmed to be the most important as regards not only the number of subjects affected and the wide geographical distribution but also the variety of organs involved, notably the lungs, the male genitals and the female breast, invariably leading to a wrong diagnosis of malignant tumour. In man, the zoonosis may be described as emerging: whereas until the middle of the last century only a few dozen cases were reported, in the last 50 years the number has gradually increased to reach the present 782.

Serological assays on eight cases of human dirofilariasis identified by morphology and DNA diagnostics

Specimens of Dirofilaria sp. removed from eight Italian patients were identified as D. repens by morphology and confirmed as such by a PCR-based method of DNA analysis. Blood samples were also drawn from the patients so that two serological tests (ELISA and western blot), one based on the recognition of molecular markers recently identified in the somatic antigenic complex of D. repens, could be evaluated. The antigenic complex used in the ELISA only gave a weak sensitivity. However, the western-blot assays, based on the polypeptide molecular markers, were found to have greater sensitivity and should be useful in detecting human cases of dirofilariasis.

The species of the genus Dirofilaria, Railliet & Henry, 1911

Some authors divide the genus Dirofilaria into two subgenera. The subgenus Dirofilaria consists of 5 apparently valid species (D. ailure, D. freitasi, D. immitis, D. lutrae, D. spectans) and 7 species of questionable validity (D. fausti, D. indica, D. louisianensis, D. magalhaesi, D. nasuae, D. pongoi, D. spirocauda). The subgenus Nochtiella consists of 22 apparently valid species (D. acutiuscula, D. bonnei, D. cancrivori, D. corynodes, D. genettae, D. granulosa, D. incrassata, D. linstowi, D. macacae, D. macrodemos, D. magnilarvatum, D. minor, D. pagumae, D. panamensis, D. repens, D. sachsi, D. striata, D. subdermata, D. sudanensis, D. tawila, D. tenuis, D. ursi) and 8 species of questionable validity (D. aethiops, D. andersoni, D. conjunctivae, D. desportesi, D. hystrix, D. schoutedeni, D. spinosa, D. subcutanea). Actually, 10 species of the genus Dirofilaria (D. asymmetrica, D. digitala, D. kuelzii, D. ochmanni, D. pauliani, D. roemeri, D. scapiceps, D. timidi, D. uniformis, D. websteri) are attributed to other genus.

Advances in the identification of Dirofilaria repens and Dirofilaria immitis by a PCR-based approach

The differential epidemiology of D. repens and D. immitis is still poorly understood due to the lack of a diagnostic method which would make possible the routine identification of these parasites as developing larvae either in the vector or in unsuitable hosts, including man. The PCR-based method here described allows: i) the unambiguous identification of mature and immature adult worms in bioptic material, of microfilariae in blood samples and of developing larvae in mosquito vectors; ii) the analysis of samples stored either dry or in various preservation media, with the exception of formalin. The high specificity and sensitivity of the diagnosis improve the perspectives for comparative epidemiological investigations on D. repens and D. immitis in areas where the two nematodes are sympatric.

[Imported parasites in dogs: Dirofilaria repens and Dipetalonema reconditum]

Between June 1993 and May 1996 infections with filariae were diagnosed in 80 dogs. Five animals were infected with Dirofilaria repens and three other dogs with Dipetalonema reconditum. One of the D. reconditum positive dogs was also infected with Dirofilaria immitis. An epidemiological analysis of the cases was possible for three D. repens and two D. reconditum infected dogs. Two of the dogs with D. repens infections had been imported from Italy or Greece, the third dog had been taken by its owner to Hungary and former Yugoslavia. The dogs infected with D. reconditum were imported from Corse or Spain. Regarding the other 72 dogs with filariae, 45 animals were infected with D. immitis. For 27 dogs being negative in the D. immitis ELISA, microfilariae have been demonstrated. However, a histochemical species differentiation of the microfilariae was not possible because fresh blood smears were not available.

[Subcutaneous human dirofilariasis]

After a short review of the literature, starting from the last decades of the past century, the current classification of the Dirofilaria genus is shown with its two subgenera: D. immitis and D. nochtiella (repens, tenuis and ursi). The first case of subcutaneous and pulmonary dirofilariasis caused in Italy by D. repens is then shown as well as a research on dog populations in which D. immitis is prevalent. The fact that D. immitis has not yet been isolated in humans, in Italy, is probably due to D. repens vectors being more anthropophile. Finally, the latest cases of dirofilariasis from D. repens reported in Italy are taken into consideration along with the one isolated by the Authors, complete with illustrations. The case presented has been diagnosed on the basis of the histological examination carried out on a soft nodule detected in the right pectoral region; furthermore, eosinophilia and an elevated value PRIST were present.

Human dirofilariasis due to Dirofilaria (Nochtiella) repens: a review of world literature

For some Dirofilaria spp. of zoonotic importance, such as D.immitis, D.tenuis, D.ursi, reviews of human cases were often published. For D. repens there is no published information giving a picture of the importance of the problem and of the geographical distribution of the parasite in the world. From a study of the international literature and from direct experience (our workgroup observed 75 cases in Italy) we have ascertained that the condition associated with D. repens is the most frequent and the most widely distributed in the world, of the dirofilariases of medical relevance: comprehensively 397 cases were recorded in 30 countries, exclusively in the Old World, with endemic foci in Southern and Eastern Europe, Asia Minor, Central Asia and Sri Lanka. Apparently, the most affected country is Italy with a total of 168 cases. The most common localisations are the subcutaneous (normally nodular) and the submucosal (nodular or not). The most affected areas are the head, the thoracic wall and the upper limbs. However, 15 cases with internal localisations are recorded (9 of them being pulmonary) which were always diagnosed erroneously as malignant neoplasiae. Clinical diagnosis for the other localisations was also generally wrong with the exception of the subconjunctival cases, where because of the transparency of the bulbar conjunctiva, it is possible to see the parasite directly. The correct diagnosis is usually histological, based on the identification of the nematode using the morphological characters of the species to differentiate it from the other dirofilariae or other erratic nematodes. It is possible that the zoonosis in man is more frequent than shown by the literature: many cases are not diagnosed, viz. not published, others recover spontaneously without medical intervention.

Serological diagnosis of subcutaneous dirofilariosis

We present serological evidence that Dirofilaria immitis was the causative agent of subcutaneous nodules in two patients. ELISA and enzyme-linked immunoblot analysis showed that the two human sera had a reactivity pattern similar to that of D. immitis rabbit immune serum. The reaction pattern of the human sera was very different to that of Dirofilaria repens rabbit immune serum. In the light of our findings, the traditional view that subcutaneous filarial nodules are due to D. repens has to be revised.

Zoonotic filaria of possible American origin in Italy

From a 31 year old man, resident in Monfalcone (Venezia Giulia) a nodule in the right temporal region was surgically removed in January 1992 containing a filiform living nematode. On the basis of the morphological characters, the nematode proved to be Dirofilaria sp. subgenus Nochtiella but the exact species was not possible to define. The medical history indicated that the patient had spent the last summer in Florida.

Dirofilariasis in Kuwait: first report of human infection due to Dirofilaria repens in the Arabian Gulf

Zoonotic dirofilariasis has been reported sporadically from many areas of the world but thus far, there are no such reports from the Arabian Peninsula. We present the first report of human dirofilariasis from this region in the Middle East and discuss the significance of the finding. A fixed, elongated mass in the abdominal wall of a 50-year-old Kuwaiti man was excised and a worm was identified in an abscess in tissue sections. The location of the nodule in subcutaneous tissue, the diameter of the worm in section, the multilayered cuticle with fine longitudinal ridges on the external layer, prominent internal cuticular ridges, and abundant somatic muscles suggested the diagnosis of the worm as Dirofilaria (Nochetiella) repens, a natural parasite of dogs and cats in Asia, Africa, and Europe.

Human subcutaneous dirofilariasis caused by Dirofilaria repens in Ibiza, Spain

A case of human subcutaneous dirofilariasis contracted in Ibiza, Spain is reported. An incomplete nematode extracted from the eyelid of a woman patient was identified on the basis of its anatomic and histologic characteristics as a nongravid adult female of the species Dirofilaria repens. The subcutaneous location of the worm, together with the epidemiologic data, support this finding.

Genetic characterization of Dirofilaria repens and D. immitis by electrophoretic analysis of gene-enzyme systems

A multilocus genetic analysis based on protein electrophoresis was carried out on 39 adult specimens of Dirofilaria repens and 31 of D. immitis. Seventeen enzymatic loci provided reliable electrophoretic patterns which were compared in the two species. All loci except one were monomorphic. Fixed alternative allozymes were found at 13 loci while only 3 loci shared apparently the same allozyme in the two species. The polymorphic locus, Pgm, also showed alternative allozymes. This remarkably high genetic divergence, which presumably reflects a very old speciation process, allows an easy characterization of D. repens and D. immitis and supports their classification in the subgenera Nochtiella and Dirofilaria, respectively.

[The third case of dirofilariasis conjunctivae in Turkey]

An Immature female Dirofilaria (Nochtiella) conjunctivae has been obtained from a nodule located in fifth finger of right foot of a 8 years-old girl.

Filaria conjunctivae

A conjunctival neoformation, excised in a 44-year-old healthy Italian man, was histologically diagnosed as Dirofilaria conjunctivae, which is probably Dirofilaria repens, a natural parasite found in dogs of European countries. This parasite rarely infests man in subcutaneous tissues, palpebral, orbital or conjunctival regions. In this case, as in those described by others, the vector remained unknown.

Identification of some common infective filarial larvae in Malaysia

Infective larvae of Wuchereria, Brugia, Breinlia, Dirofilaria and Setaria species from an experimental vector, Aedes togoi, are compared. The distinctive bubble-like caudal papillae of Wuchereria bancrofti are readily distinguishable from the protuberant ones of Brugia spp; the 'ear-like' papillae of Breinlia are distinct from the 'knob-like' ones of Dirofilaria or the 'thorn-like' terminal papilla of Setaria.