Unusual feline Dirofilaria immitis infection: a case report / Infecção incomum por Dirofilaria immitis em felino: relato de caso

Abstract Cats are less susceptible to Dirofilaria immitis infection than dogs. Although rare, the feline disease can be fatal even with low parasitic loads. The infection is often asymptomatic or has non-specific symptoms that are mainly associated with the death of immature worms. Microfilaremia is rare and transient. Normally, microfilaremia, when present, lasts for not more than 33 days. This study describes a feline case presenting with non-specific clinical signs and prolonged microfilaremia. Case: a random bred cat infected by feline leukemia virus (FeLV) that was found to be microfilaremic by chance. The infection was detected by the presence of microfilariae in a blood smear and was confirmed by antigen test (SNAP Feline Triple Test, Idexx®) and echocardiogram.

Resumo Gatos são menos susceptíveis à infecção por Dirofilaria immitis do que cães. Apesar de rara, a doença nos gatos pode ser fatal mesmo com baixas cargas parasitárias. Muitas vezes, a doença é assintomática ou apresenta sintomas inespecíficos, principalmente associados com a morte de formas parasitárias imaturas. Microfilaremia é rara e transitória. Normalmente, quando ocorre microfilaremia, ela permanece por, no máximo, 33 dias. Este estudo descreve o caso de um felino que apresentava sinais inespecíficos e microfilaremia prolongada: um gato sem raça definida, portador de infecção pelo vírus da leucemia felina (FeLV) que foi diagnosticado como microfilaremico ao acaso. A infecção foi detectada pela presença de microfilárias em esfregaço sanguíneo e, posteriormente, confirmada pelo teste de antígenos (SNAP Feline Triple Test, Idexx®) e por ecocardiograma.

Periorbital mass with cellulitis caused by dirofilaria.

Dirofilariasis is a zoonotic disease caused by Dirofilaria, a parasite of domestic and wild animals. The disease is transmitted by inoculation of mosquitoes infected with the microfilariae during their blood meal. Accidental infection of man results in lung nodule, subcutaneous mass anywhere in the body or ocular lesion that may be subconjunctival or periorbital. The incidence of ocular dirofilariasis is on the rise in several parts of India particularly in Kerala. Here we report a case of ocular dirofilariasis with cellulitis presenting as a periorbital mass.

Diagnóstico de Dirofilaria immitis en el municipio Sucre, estado Sucre, Venezuela / Diagnosis of Dirofilaria immitis in the municipality of Sucre, Sucre state, Venezuela

La dirofilariasis es una patología parasitaria, causada por los nematodos Dirofilaria immitis y D. repens, principalmente. Mientras que D. immitis presenta distribución mundial, D. repens se extiende por el viejo mundo. Ambas especies afectan a caninos y felinos domésticos y salvajes, así como a humanos, por lo que es un problema de salud pública mundial. En este estudio se determinó la prevalencia de D. immitis, en caninos del municipio Sucre, estado Sucre, Venezuela. Se tomaron muestras sanguíneas a 138 caninos domésticos, mayores de seis meses, sin distinción de raza ni sexo, previo consentimiento informado por sus propietarios. El diagnóstico parasitológico de las microfilarias circulantes se realizó por examen directo y método de concentración Knott modificado; las características morfológicas fueron observadas en extendidos teñidos con Giemsa. Se utilizó un estuche comercial, para la captura de antígenos de excreción-secreción de D. immitis. De los 138 caninos estudiados, 12 casos positivos (8,7%) fueron detectados parasitológicamente, mientras que por el estuche comercial se detectaron antígenos en 20 caninos (14,5%), lo que demuestra que existe una dirofilariasis oculta en el 5,8% de los casos evaluados. Uno de los perros microfilarémicos, no presentó antígenos circulantes. La prevalencia de dirofilariasis en el municipio Sucre, estado Sucre fue de 15,2%. Este reporte de dirofilariasis canina en el municipio Sucre, representa un importante aporte en el levantamiento epidemiológico de la enfermedad. Futuros estudios permitirán evaluar el riesgo de infección de las personas que conviven con los perros con dirofilariasis.

Heartworm is a parasitic disease, caused by nematodes Dirofilaria immitis and D. repens, mainly. While D. immitis presents worldwide distribution, D. repens extends the old world. Both species affect canines and felines domestic and wild, as well as human, so it is a global public health problem. In this study we determined the prevalence of D. immitis in dogs in the municipality of Sucre, Sucre state, Venezuela. Blood samples were taken for 138 domestic dogs, over six months, regardless of race or sex, prior informed consent by their owners. The parasitological diagnosis of circulating microfilariae was done by direct examination and concentration method modified Knott, the morphological characteristics were observed in Giemsa-stained smears. We used a commercial kit, for the capture of excretory-secretory antigens of D. immitis. Of the 138 dogs studied, 12 cases (8.7%) were detected parasitologically, whereas the commercial kit antigens were detected in 20 dogs (14.5%), demonstrating that there is an occult infections in 5.8% of the cases. One of the dogs with microfilariae in blood, did not submit antigens circulating. The prevalence of heartworm in the municipality of Sucre, Sucre state was 15.2%. This report of canine heartworm in the municipality of Sucre, represents an important contribution in an epidemiologic survey of the disease. Future studies will assess the risk of infection for people living with dogs with heartworm disease.

Catheter-guided percutaneous heartworm removal using a nitinol basket in dogs with caval syndrome

Carval syndrome is a severe heartworm infection where the worms have migrated to the right atrium and vena cava; this condition is associated with a myriad of clinical signs. Several non-surgical and interventional methods are currently used for mechanical worm removal. However, the success rate and complications related to these methods are heavily dependent on methodology and retrieval devices used. In this study, we developed a catheter-guided heartworm removal method using a retrieval basket that can easily access pulmonary arteries and increase the number of worms removed per procedure. With this technique, we successfully treated four dogs with caval syndrome.

Dirofilariose: zoonose emergente negligenciada: [revisão] / Dirofilariasis: neglected emerging zoonosis: [revision]

A dirofilariose é uma zoonose pouco conhecida causada por Dirofilaria spp., nematódeo mais conhecido como verme do coração dos cães (Dirofilaria immitis), parasita do sistema circulatório desses animais, mas que também pode acometer gatos e o ser humano. Sua ocorrência está intimamente ligada à presença de mosquitos vetores (Aedes spp., Anopheles spp., Culex spp.), condições climáticas favoráveis, assim como trânsito entre regiões indenes e endêmicas/epidêmicas. O ser humano pode se infectar com D. immitis (pulmão), Dirofilaria repens (pulmão, subcutâneo) e Dirofilaria tenuis (subcutâneo). A fisiopatologia está intimamente ligada à morte do parasita onde, no cão, pode induzir a obstrução de vasos circulatórios e no ser humano produzir uma lesão nodular com intensa reação inflamatória no parênquima pulmonar com formato de moeda observada nas radiografias. Pode ser diagnosticada pelo exame físico, pela detecção de microfilárias na circulação sangüínea, imunoadsorção enzimático (ELISA), alterações radiográficas, ecocardiografia, ultrassonografia e necropsia. Há riscos no tratamento, sendo a prevenção com a utilização de drogas nos animais o método mais eficaz, principalmente em visitas a áreas endêmicas ou epidêmicas, diminuindo-se, assim, o risco para saúde pública devido à disseminação do parasita.

Dirofilariasis is an unknown zoonosis, caused by Dirofilaria spp, nematodea most known as dog's heartworm (Dirofilaria immitis), which parasites the vascular system of these animals, but infects cats and human beings too. Its occurrence is highly linked to the presence of mosquitoes (Aedes spp., Anopheles spp., Culex spp.), adequate climatic conditions, as well as the transit between infection-free and endemic/epidemic regions. Human beings can be infected by D. immitis (lung), Dirofilaria repens (lung, subcutaneous) and Dirofilaria tenuis (subcutaneous). The physiopathology is highly dependent of the parasite death, inducing the obstruction of the vascular system in dogs and nodular lesions with intense inflammatory reaction in pulmonary parenchyma, like a coin lesion, observed in the radiographs. It can be diagnosed by physical examination, microfilarias detection on the vascular system, enzymatic immunoadsortion (ELISA), radiographic alterations, echocardiography, ultrasonography and necropsy. There are risks on treatment and drug prevention in animals is the most efficient method, mainly in visits to endemic or epidemic areas, decreasing the risk to public health due to the parasite dissemination.

Ectopic Migration of an Adult Heartworm in a Dog with Dirofilariasis (Case Report)

A 3-yr-old female mongrel dog was referred to the Veterinary Teaching Hospital of Chungnam National University in the Republic of Korea. An adult heartworm, Dirofilaria immitis, was found in the abdominal cavity of the dog during spaying. Dirofilariasis in this dog was also diagnosed by modified Knott's test, ELISA test, and PCR analysis. The present case is the first report on the migration of an adult dog heartworm to the abdominal cavity of a dog in the Republic of Korea.

Focos de dirofilariose canina na Ilha do Marajó: um fator de risco para a saúde humana / Focus of canine heartworm disease in Marajó Island, North of Brazil: a risk factor for human health

A ocorrência de dirofilariose pulmonar humana relaciona-se com a prevalência de infecção por Dirofilaria immitis na população canina. Várias espécies de mosquitos são vetores desse nematóide. Analisaram-se amostras de sangue canino coletados nas vilas Pingo d'Agua e União, município de Salvaterra (Ilha do Marajó, PA), em junho, 2004 (n=34) e abril, 2005 (N=90). Os diagnósticos parasitológico e imunológico (ELISA - kit SNAP® 3DX™, Biobrasil) foram comparados (chi2, alfa=0,05) no exame de 34 amostras. A prevalência na população (N=90) foi avaliada pelo ELISA. O ELISA revelou mais positivos (25/34; 73,5 por cento) que a gota espessa (23/34, 67,6 por cento) e o Knott (21/34, 61,8 por cento), mas a diferença não foi significativa (p>0,05). A freqüência de infecção por D. immitis na faixa de 0 a 2 anos foi 58 por cento, enquanto em cães mais velhos foi 100 por cento. A prevalência da dirofilariose canina em Pingo d'Agua e Vila União foi alta (53,5 por cento), indicando risco de transmissão do parasito às pessoas nessa área.

The occurrence of human pulmonary dirofilariasis maintains a relation with the prevalence of Dirofilaria immitis infection in the canine population. Several mosquito species are vectors of this nematode. Canine blood samples collected in Pingo d'Agua and União villages, Salvaterra municipality (Marajó Island, Pará), in June, 2004 (n=34) and April, 2005 (N=90) were analyzed. Parasitological and immunological (ELISA - kit SNAP® 3DX™, Biobrasil) diagnoses were compared following the examination of 34 samples. The prevalence in the population (N=90) was evaluated by means of ELISA. ELISA revealed more positive samples (25/34; 73.5 percent) than thick smears (23/34, 67.6 percent) or Knott (21/34, 61.8 percent), but the differences were not significant (p>0.05). The frequency of D. immitis infection was 58 percent in dogs ranging from 0-2 years old, whereas in older dogs it was 100 percent. The prevalence of canine dirofilariasis was high in Pingo d'Agua and Vila União (53.5 percent), indicating the risk of parasite transmission to the people in this area.

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.

A preliminary study on in vitro transmission of Dirofilaria immitis infective stage larvae by Aedes aegypti (L.) (Diptera: Culicidae).

This study was performed to study an in vitro transmission of infective stage larvae from the mosquito proboscis. There were five experiments with 949 mosquitoes. Liverpool strain of Aedes aegypti (L.) were used in this study. They were allowed to feed on D. immitis infected dogs with different microfilarial levels which were 1,650, 1,950, 9,000, 9,250, and 11,550 microfilariae per one ml of blood. Mosquitoes were forced to feed on solution (5% sucrose in 5% dog serum) in capillary tubes for 20 minutes at 7-34 days post-blood feeding. Solutions in capillary tubes then were examined and mosquitoes were dissected and examined for D. immitis larvae under a light microscope. Second stage larvae could be found in the abdomen and malpighian tubules of mosquitoes and third stage larvae can be found in the abdomen, malpighian tubules, thorax, and proboscis of mosquitoes with different levels of infection. No larvae were detected in the solution in capillary tubes of all experiments.

Autogenous Aedes togoi sub-colony (Chanthaburi, Thailand strain), an efficient laboratory vector in study of filariasis.

Comparative filarial susceptibility and biology between stock colony and selectively autogenous Aedes. togoi sub-colony were carried out to determine the laboratorial vector-capacity and viability of autogenous sub-colony. The results of susceptibility revealed that the selectively autogenous Ae. togoi sub-colony yielded higher susceptibility than the stock colony, ie Dirofilaria immitis: susceptibility rates=80.00% [Exp1(F8)] and 76.19% [Exp2(F17)] (autogenous sub-colony), 53.33% (Exp1) and 71.43% (Exp2) (stock colony); Brugia malayi: susceptibility rates=83.33% [Exp1(F17)] and 84.38% [Exp2(F19)] (autogenous sub-colony), 81.25% (Exp1) and 75.00% (Exp2) (stock colony), but not at the level of statistically significant differences except the Exp1 of D. immitis, which was significant difference. In addition, the average No. L3 per infected mosquito in the selective autogenous sub-colony (D. immitis: Exp1=3.37, Exp2=3.19; B. mallayi: Exp1=8.80, Exp2=3.37) was also higher than in stock colony (D. immitis: Exp1=2.44, Exp2=2.73; B. malayi: Exp1=7.85, Exp2=3.02), but not at the level of statistically significant difference. The results of comparisons on some biological aspects demonstrated that most of the cases they have similar biology except the average egg deposition per gravid female of stock colony (130.17+/-43.33) was significantly more than selectively autogenous sub-colony(F9) (94.33+/-13.69), egg length x width 575.62+/-18.06 microm x 186.15+/-9.35 microm of stock colony was significantly larger than selectively autogenous sub-colony(F9) 560.49+/-18.96 microm x 177.99+/-8.40 microm, and mean longevity of adult female of stock colony [41.60(6-61)] was significantly longer than selectively autogenous sub-colony(F9) [35.00(5-39)]. The selectively autogenous sub-colony was established and twenty-two successive generations have been colonized.

Infecçäo experimental de Aedes fluviatilis (Lutz, 1904) por Dirofilaria immitis (Leidy, 1856) / Experimental infection of Aedes fluviatilis (Lutz, 1904) by dlirofiliaria immitis (Leidy, 1856)

Foi testada, experimentalmente, a suscetibilidade de Aedes fluviatilis à infecçäo por larvas de Dirofiloria immitis. Compararam-se os percentuais de sobrevivencia entre mosquitos infectados e näo infectados e observou-se que säo menores nos infectados. O desenvolvimento larvário mostrou-se assincrônico e, muitas vezes, as larvas näo ultrapassaram o primeiro estádio. Em pequena proporçäo dos mosquitos foram encontradas L3, observáveis entre o 14§ e o 22§ dias pós-infecçäo. Encontrou-se, em geral, uma ou duas, no máximo seis L3 por mosquito

A comparison of the efficiency of the Nuclepore and Millipore filtration systems for detecting microfilariae.

Using Brugia pahangi or Dirofilaria immitis as the test organisms no significant difference could be detected between Nuclepore and Millipore filters. It was found that 0.7% of microfilariae passed through the Millipore and 1% through the Nuclepore filters. No microfilariae were lost from the Nuclepore membrane during the staining process.