[Morphological and molecular identification of canine filariae in a semi-rural district of the Metropolitan Region in Chile]. / Identificación morfológica y molecular de filarías caninas en una comuna semi-rural de la Región Metropolitana, Chile.

INTRODUCTION: To date, there has been no definitive confirmation of the presence of zoonotic dirofilariasis in dogs in Chile. OBJECTIVES: To study the presence of dirofilarias in blood samples from dogs collected in a semi-rural district near Santiago and to compare their frequency in dogs with and without dermatological manifestations. METHODS: We examined 100 blood samples for dog filariae infections using microscopic methods (modified Knott technique). 50 dogs presented dermatological symptoms or signs compatible with filarial infections and 50 were asymptomatic. ITS-2 and 12s rDNA gene amplification by PCR and sequencing were performed in samples microscopically positive for microfilariae. Results. We observed microfilariae in 22 dogs (22%). Of these, 16/50 (32%) were symptomatic and 6/50 (12%) were asymptomatic (p = 0.02). Morphologically, the majority of micro-filariae were similar to Dirofilaria repens, although many had a bigger size than previously described. Nucleotide sequencing of the amplified genes showed no more than 95% homology with the D. repens sequences available for comparison. D. reconditum and D. dracunculoides infections were also identified. CONCLUSIONS: These features might indicate the presence of new species of Dirofilaria or a D. repens close related variant in Chile.

Identificación morfológica y molecular de filarías caninas en una comuna semi-rural de la Región Metropolitana, Chile / Morphological and molecular identification of canine filariae in a semi-rural district of the Metropolitan Region in Chile

Introduction: To date, there has been no definitive confirmation of the presence of zoonotic dirofilariasis in dogs in Chile. Objectives: To study the presence of dirofilarias in blood samples from dogs collected in a semi-rural district near Santiago and to compare their frequency in dogs with and without dermatological manifestations. Methods: We examined 100 blood samples for dog filariae infections using microscopic methods (modified Knott technique). 50 dogs presented dermatological symptoms or signs compatible with filarial infections and 50 were asymptomatic. ITS-2 and 12s rDNA gene amplification by PCR and sequencing were performed in samples microscopically positive for microfilariae. Results. We observed microfilariae in 22 dogs (22%). Of these, 16/50 (32%) were symptomatic and 6/50 (12%) were asymptomatic (p = 0.02). Morphologically, the majority of micro-filariae were similar to Dirofilaria repens, although many had a bigger size than previously described. Nucleotide sequencing of the amplified genes showed no more than 95% homology with the D. repens sequences available for comparison. D. reconditum and D. dracunculoides infections were also identified. Conclusions: These features might indicate the presence of new species of Dirofilaria or a D. repens close related variant in Chile.

Introducción: A la fecha no hay datos concluyentes en Chile respecto a la presencia de dirofilariasis zoonótica en perros. Objetivos: Identificar la presencia de dirofilarias en sangre de perros de una comuna semi-rural cercana a Santiago y comparar su frecuencia en animales con y sin manifestaciones dermatológicas. Materialy Métodos. Se examinó un frotis sanguíneo de 100 perros en busca de microfilarias mediante observación microscópica (técnica de Knott modificada). Cincuenta perros presentaban síntomas o signos dermatológicos que se han asociado a esta parasitosis y 50 eran asintomáticos. Se amplificaron los genes ITS-2 y 12s ADNr de filarías en las muestras con microfilarias al frotis, secuenciando los fragmentos amplificados. Resultados: Se observaron microfilarias en 22 perros (22%), 16/50 (32%) sintomáticos y 6/50 (12%) asintomáticos (p = 0,02). Morfológicamente, la mayoría de las microfilarias observadas fueron similares a D. repens; sin embargo, una gran proporción mostró un tamaño mayor al descrito para esta especie. Las secuencias nucleotídicas de los genes amplificados mostraron una homología no mayor al 95% con las secuencias de D. repens disponibles para comparación. Se identificaron además dos especies poco patógenas, D. reconditum por morfología y secuenciación genética y D. dracunculoides por morfología. Conclusiones: Los resultados indican la existencia de una nueva especie de Dirofilaria cercanamente relacionada a D. repens o de una variante de esta especie.

Identification and phylogenetic analysis of Dirofilaria ursi (Nematoda: Filarioidea) from Wisconsin black bears (Ursus americanus) and its Wolbachia endosymbiont.

Dirofilaria ursi is a filarial nematode of American black bears (Ursus americanus Pallas, 1780) that is vectored by black flies (Simuliidae) in many parts of the United States. In northwestern Wisconsin, the prevalence of microfilaremic bears during the fall hunting season was 21% (n = 47). Unsheathed blood microfilariae from Wisconsin bears possess characters consistent with the original description of D. ursi, as do adult worms observed histologically and grossly. Immunohistochemistry was used to identify the Wolbachia endosymbiont in the hypodermis and lateral cords of an adult female D. ursi. Amplification of wsp, gatB, coxA, fbpA, and ftsZ bacterial sequences from parasite DNA confirmed the presence of Wolbachia, and molecular phylogenetic analysis of the Wolbachia ftsZ gene groups the endosymbiont with Wolbachia from D. immitis and D. repens. Phylogenetic analysis of D. ursi 5s rDNA sequence confirms the morphological observations grouping this parasite as a member of Dirofilaria, and within the Dirofilaria - Onchocerca clade of filarial nematodes. This is the first report of Wolbachia characterization and molecular phylogeny information for D. ursi.

[Human dirofilariasis: diagnosis and the pattern of pathogen-host relations].

Until recently, there has been no consensus of opinion as to that D.repens females can develop in the accidental host (man). The role of man is regarded as a biological dead end for Dirofilaria that are unable to develop the adult stage; human Dirofilaria migration is considered to be larval by the type of larva migrans. Studying these matters on a specific material of 140 cases of invasion by Dirofilaria that had been eliminated in patients in different seasons and the length of their bodies measured showed that the maximum number (51.4%) was mature females, 120 to 190 mm in size; 35.7 and 12.85% had a length of 70-115 and 40-65 mm, respectively, which corresponds to immature young and juvenile specimens. This suggests that Dirofilaria normally develop and achieve the adult stage in the accidental host. A correlation was found in the sizes of the body and the time of D. repens development. Thus, the human organism is not a biological dead end for Dirofllaria. The migration of adult Dirofilaria should be appraised as the imago-migrans phenomenon: As the particular diagnostic sign, it will aid a physician to establish a correct parasitiological diagnosis at the early stages of the disease. In recent years, there has been new evidence in the diagnosis of dirofilariasis that microfilaria have been detected in the skin tumor puncture specimen and blood of the patients. In this connection, it is conceivable that man may be an actual source of mosquito infection even in the presence and paucity of mature males and females.

Human Dirofilaria repens infection in Serbia.

Human infection by Dirofilaria repens in Serbia has been increasing steadily. The first case was reported in 1971, presented in the form of a single subcutaneous nodule on the back of a young boy. As established by a literature search, eight additional cases were reported until mid-2001. The most frequent site of infection was subcutaneous tissue, with the exception of two cases, in which parasites were found in subconjunctiva and epididymis. Our study, conducted from 2001 to 2008, encompasses 19 new cases. Most of them (63.1%) presented as ocular or periocular infections, in which the parasite was typically found under the conjunctiva. In other cases a parasitic nodule was localized in the temporal region of the head, epididymis, testicle, abdomen, breast or arm. The diagnosis was made by morphological and histological analysis of the extracted intact worms and parasite sections from the tissue. Morphology of the filarial worms was well preserved in more than half of the cases (12/19) and there was never more than one parasite found inside the lesions. Adult worms and immature nematodes were observed in nine and seven cases, respectively. Furthermore, in two cases microfilariae were discovered inside the pseudocoelom, sections of the female reproductive tubes filled with clearly visible larval stages. Dirofilaria repens infection was diagnosed by its morphological features (17/19) or by performing polymerase chain reactions (PCR) using paraffin-embedded tissues (2/19) in the cases where the morphology was insufficient for identification and the parasites had been determined initially as Dirofilaria spp. The amplified 246 bp PCR product showed that the worms were D. repens.

[The first autochthonous case of subcutaneous dirofilariosis in Austria]. / Der erste autochthone Fall einer subkutanen Dirofilariose in Osterreich.

Dirofilaria repens, a common parasite of carnivore mammals, is transmitted by mosquitos and may also infect humans accidentally causing a subcutaneous dirofilariosis. Autochthonous infections of dogs, foxes or cats with D. repens has not been found in Austria so far; however, 12 cases of imported subcutaneous dirofilariosis in man were noticed between 1981 and 2005. The recent case report deals with the 13(th) human case, which has to be considered as the first autochthonously acquired in Austria.

Three new cases of human infection with Dirofilaria repens, one pulmonary and two subcutaneous, in the Egyptian governorate of Assiut.

Human dirofilariasis caused by Dirofilaria repens is a parasitic infection, currently considered to be an emerging zoonosis, that has been observed in many areas of the Old World. Dogs are the main 'reservoir' host. In humans, D. repens can cause inflammatory nodules, most commonly in the subcutaneous tissues or in the subconjunctival space. Lung involvement, which is the most common of the non-cutaneous and non-ocular manifestations, is frequently mis-diagnosed as a primary or metastatic lung tumour. Two new subcutaneous cases and one new pulmonary case, all observed in the Egyptian governorate of Assiut, are described here. This represents the first report of human pulmonary dirofilariasis caused by D. repens on the African continent. All the worms collected from the cases, including a living worm from the left lung of the pulmonary case, were identified morphologically, and the identity of the lung parasite was confirmed by PCR.

[Human dirofilariasis: 3 cases in the south of France]. / Dirofilariose humaine: 3 cas autochtones dans le sud de la France.

INTRODUCTION: Dirofilariasis is a zoonosis usually found in dogs and cats. It is rare in humans, who are dead-end hosts for the parasite. CASES: We report 3 cases of subcutaneous dirofilariasis due to Dirofilaria repens, contracted in the south of France (Alpes-Maritimes and Corsica). In the first two cases, the dirofilariasis manifested as lymph node enlargement; in the third case, lung disease suggested a systemic diffusion of microfilariae. DISCUSSION: Dirofilaria repens dirofilariasis is due to the transmission of microfilariae by some mosquito bites (Aedes, Culex, Anopheles, Mansonia, Psorophora and Taeniorhynchus). Usually only one larva develops, producing an immature adult worm inside a node. Ultrasound examination may suggest the parasitic origin of the lesion. It is treated surgically, by excision, without chemotherapy. Very rarely, an adult worm may mature and produce systemic diffusion of microfilariae. The nodule in the third case contained a gravid adult female worm but we found no microfilariae. Dirofilariosis can present problems in diagnosis and treatment. It must be considered in patients with an isolated nodule.

Subcutaneous dirofilariasis caused by Dirofilaria repens.

Human dirofilariasis caused by Dirofilaria repens D. repens is a common zoonosis in the Mediterranean countries and parts of South Asia. During the last decade, it has been reported from countries previously considered non-endemic. This is likely due to the increased awareness regarding Dirofilaria infection. In some such cases however, dirofilariasis correlated with the travel of the patient to the endemic areas. We present the case of a Saudi male who had D. repens infection in the subcutaneous tissues of the forearm. The patient had traveled to Iraq, Syria, United Arab Emirates and Kuwait in the last 2 years. However, the known Dirofilaria endemic countries were not visited. Any prior occurrence of the human dirofilariasis in the Kingdom of Saudi Arabia is not documented. Lack of epidemiological studies or incidence reports in the Arabian region precludes any factual evaluation of Dirofilaria prevalence, which requires increased awareness amongst health workers regarding its potential occurrence in the native population.

Dirofilarial infection presenting as a facial mass: case report of an emerging zoonosis.

Dirofilariasis is a parasitic infection caused by nematodes. Human infection remains rare but is increasing in scope, particularly in endemic areas. Dirofilariasis typically presents as a subcutaneous mass or with pulmonary nodules. Here, we present the case of a 73-year-old woman whose asymptomatic facial mass was caused by dirofilarial infection. The pathophysiology, diagnosis, and treatment of dirofilariasis of the head and neck will be discussed. In endemic areas, dirofilariasis must be considered in the differential diagnosis of facial masses.

New human Dirofilarioses in Hungary.

About ten cases of filariosis have recently been recorded in the Hungarian medical literature, six of them caused by Dirofilaria repens. Dirofilaria repensis a mosquito-transmitted filaroid worm in the subcutaneous tissue of dogs and cats in the temperate areas of the Old World. It accidentally infects man, too, and can remain unidentified due to physicians, poor knowledge of the parasite. In the last two years six new Dirofilaria repensinfections have been found in various parts of the country: five localised dermally and one in the deep tissues. Two of the cases might have been acquired in Italy during summer travels. Four patients, however, have never been abroad, these cases must be considered autochtonous infections. The thickness of the multilayered cuticle of the worm, diameter of the body and the size, form and number of the longitudinal ridges on its surface are used in the histological diagnosis of the the parasite.

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.

Pitfalls and difficulties in histological diagnosis of human dirofilariasis due to Dirofilaria (Nochtiella) repens.

The authors have conducted a histologic study of over 90 cases of Dirofilaria infection in man due to Dirofilaria repens, the most extensive study of its kind in the world. On the basis of their findings, they illustrate the diagnostic difficulties that may arise when regressive phenomena render the parasite's morphologic characteristics largely or completely unrecognizable. These phenomena are due to the death of the filaria inside the inflammatory nodule weeks or months prior to surgical removal, and to the consequent invasion of inflammatory cells. They start at the nematode's natural orifices (mouth, vulva, anus, cloaca) and gradually spread throughout its body. In cases of difficult diagnosis, therefore, it is recommended that the nodule be sectioned at different points comprising caudal, cephalic and middle body aspects, so as to reveal the few morphologic features that are still recognizable and which may afford a correct diagnosis. The authors present examples of histologic sections in color plates in which the nematode was in an excellent state of preservation and others illustrating the full range of regressive phenomena, from slight to total disintegration of the bodily structure.

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.

Human dirofilariasis caused by Dirofilaria (Nochtiella) repens in Sri Lanka.

Human dirofilariasis due to Dirofilaria (Nochtiella) repens is a common zoonotic infection in Sri Lanka. Todate 70 cases are on record, and they include 3 expatriates from Russia, England and Korea, who were undoubtedly infected in Sri Lanka. Around 30-60% of dogs are infected with D. repens in various parts of the country and the mosquito vectors are Aedes aegypti, Armigeres subalbatus, Mansonia uniformis and M. annulifera. Unlike in other countries of the old world infection is most common in children under the age of 9 years, the youngest being 4 months old and the scrotum, penis and perianal regions of male children appear to be frequent sites for the worms. Dirofilaria (Dirofilaria) immitis is not present in Sri Lanka though it is present in neighbouring countries like India, and Malaysia.

[Human dirofilariasis in Sardinia: 4 new cases. Review of published cases]. / Dirofilariasi umana in Sardegna: 4 nuovi casi. Revisione dei casi pubblicati.

Four new cases of Human Dirofilariasis in Sardinia are described: I subconjunctival and 3 subcutaneous. The patients were men in 3 cases and woman in the other one. The age of the subjects varied from 35 to 58 years. The parasite, Dirofilaria repens, was in all the cases a female. From the review of the literature only 3 other cases were reported in the island. Due to the diffuse presence of both the causal agent, D. repens, in dogs and many species of Culicidae that can transmit the infection to man, it is possible that human cases are more common than reported, many cases passing undiagnosed or simply not published.

Human infection with Dirofilaria repens in Malaysia.

Human dirofilariasis is a rare infection in Malaysia. Thus far, only two human cases have been reported viz. Dirofilaria immitis and D. (Nochtiella) repens and in both instances, adult worms were recovered from infected patients. The two cases reported in the present study, one from Melaka and the other from Penang, were diagnosed histologically. Based on the diagnostic criteria for identifying Dirofilaria in tissue sections, the parasites were identified as D. (Nochtiella) repens.

Human dirofilariasis in Greece: a review of reported cases and a description of a new, subcutaneous case.

A superficial analysis of Greek reports of human cases of dirofilariasis indicated that this zoonosis is rare in Greece. However, a more detailed review of the international literature revealed several more cases, diagnosed and recorded in other countries following infection during holidays in Greece. Overall, at least 20 individuals are now known to have been infected in Greece, in all regions of the country. A new, subcutaneous case of dirofilariasis is described; the infection occurred in a 45-year-old male living in Piraeus (Athens), and was localized in the abdominal wall. Histology revealed a female Dirofilaria (Nochtiella) repens in the reactive nodule.

[Human subcutaneous dirofilariasis: 8 more cases in Italy]. / Dirofilariasi umana sottocutanea: 8 ulteriori casi in Italia.

Eight new cases of Human Subcutaneous Dirofilariasis due to Dirofilaria repens in subjects aged 14 to 83 years, 5 men and 3 women, are recorded. The patients were living in Piedmont (5 cases), Tuscany (1), Friuli-Venetia Julia (1) and Apulia (1). The nematodes were immature in 6 cases (2 males and 4 females) and adults in 2 (both females). Microfilariae in the uterus of one of them were detected.