Feline Heartworm in Clinical Settings in a High Canine Prevalence Area.

Heartworm (HTW) infection in cats is associated with persistent pulmonary pathology, even when clinical signs are absent. Treatment options for cats are limited once infected, making prevention an important topic for discussion with cat owners. In Brazil, tests to detect feline HTW infections are unavailable, likely leading to an underestimation of its impact on the wellbeing of cats. The present study investigated the seroprevalence of HTW antigen in cats living in an area with high canine HTW prevalence and investigated risk factors and clinical signs associated with HTW disease in cats from Rio de Janeiro, Brazil. Clinical examinations were conducted, and serological evaluations performed with a point-of-care test (SNAP® Feline Triple® Test, IDEXX Laboratories, Inc.). A total of 586 cats were examined. The HTW antigen seroprevalence was 1.2%. Heartworm positive results were significantly associated with vomiting and abnormal lung sounds. Results from this study indicate that cats residing in areas of high canine HTW prevalence should have HTW disease as a differential diagnosis when presenting with compatible clinical signs. Veterinarians should prioritize client education and promote regular use of effective prophylaxis to protect feline health.

Molecular characterization of canine filarioids in a previously non-endemic area of Rio de Janeiro State, Brazil.

Dirofilaria immitis is the causative agent of canine heartworm disease, a severe health problem in dogs, especially in coastal areas of tropical and subtropical regions of the world. We employed molecular methods to investigate the occurrence of canine infection by filarioids in five municipalities of Baixada Fluminense (Magé, Duque de Caxias, Guapimirim, Nova Iguaçu, and São João de Meriti), a non-endemic area of Rio de Janeiro State, Southeast Brazil. A total of 110 canine blood samples collected from 2017 to 2018 and positive for microfilariae at the modified Knott's test were screened by cPCR targeting DNA fragments of the 12S rDNA gene for filarial nematodes. Seventy-seven samples (70%) tested positive at the molecular analysis. Of these, 72 were identified as D. immitis and 5 (4.5%) as Acanthocheilonema reconditum. Dirofilaria repens was not detected in the studied municipalities of Baixada Fluminense. This is the first record of D. immitis and A. reconditum in the Baixada Fluminense region, Rio de Janeiro State, Brazil. The prevalence of D. immitis cases in the five municipalities suggests the establishment and maintenance of its enzootic cycle in the studied region, which indicate vulnerability to the occurrence of epidemic cycles and, possibly, human cases.

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.

Prevalence of Dirofilaria immitis in dogs from shelters in Vojvodina, Serbia

Background: Dirofilaria immitis is vector borne parasite of carnivores, with zoonotic potential, endemic in many parts of the world, including Europe. The aim of this study was to determine the prevalence of Dirofilaria immitis infection in dogs from shelters, especially compared to their lifestyle. Dogs living in shelters in Serbia may be at high risk of acquiring vector borne pathogens, mainly because most of them live outside in pens and backyards, in contact with vectors. Also, dogs in shelters are not always regularly treated against ectoparasites, thus, representing an easy feeding source for the vectors. The objective of this study was to determine the prevalence of Dirofilaria immitis infection in dogs from 5 shelters in South Bačka and Central Banat districts, in Autonomous Province of Vojvodina, Northern part of Serbia. Also, the objective was to compare the relation of infection with Dirofiaria immitis with age, sex, type of keeping the animals and preventive treatment in dogs. Materials, Methods & Results: Between May 2017 and October 2019, blood samples were collected from 336 randomly selected dogs from 5 shelters in 2 districts, South Bačka and Central Banat districts, in Autonomous Province of Vojvodina, Northern part of Serbia. The epidemiological survey has been conducted with all of the dogs involved in this research. The survey was designed to collect data about sex, age, lifestyles, food type, treatment against mosquitoes with insecticides and filarioid worms with macrocyclic lactones, regular testing for Dirofilaria infections. The presence of circulating microfilariae was examined using a modified Knott’s test. For the presence of circulating adult female Dirofilaria immitis antigen, serum samples were tested by commercially available enzyme-linked immunosorbent assay, which reacts to antigen of female Dirofilaria. In total, 336 dogs were examined for the presence of Dirofilaria...

Dirofilarose em uma cadela: Relato de caso

A dirofilariose é uma zoonose causada pela Dirofilaria immitis, parasita de distribuição mundial, considerado um dos parasitas mais patogênicos de cães. A maioria dos animais são assintomáticos, entretanto, a doença pode afetar diversos. Objetivou-se relatar um caso de dirofilariose em uma cadela. Ela apresentava apatia, cansaço e inapetência. Foram solicitados exames, diagnosticando-se dirofilariose. O hemograma mostrou discreta leucopenia, linfopenia e trombocitopenia. A radiografia de tórax evidenciou bronquitealérgica. O ecocardiograma mostrou a presença de uma forma adulta de Dirofilaria immits. Conclui-se que a dirofilariose induziu alterações hematológicas, porém não graves. O teste rápido foi essencial no auxílio e diagnóstico precoce.

Heartworm disease is a zoonosis caused by Dirofilaria immitis, a worldwide distribution parasite, considered one of the most pathogenic parasites in dogs. Most of the animals are asymptomatic, however, the disease can affect several. The objective of this study was to report a case of heartworm disease in a female dog. She was apathetic, tired, and inept. Exams were requested, diagnosing heartworm disease. The hemogram showed discrete leukopenia, lymphopenia and thrombocytopenia. Chest x-ray revealed allergic bronchitis. The echocardiogram showed the presence of an adult form of Dirofilaria immits. It was concluded that hear tworm disease induced hematological alterations, but not severe ones. Rapid testing was essential in aiding and early diagnosis.

Dirofilarose em uma cadela: Relato de caso

A dirofilariose é uma zoonose causada pela Dirofilaria immitis, parasita de distribuição mundial, considerado um dos parasitas mais patogênicos de cães. A maioria dos animais são assintomáticos, entretanto, a doença pode afetar diversos. Objetivou-se relatar um caso de dirofilariose em uma cadela. Ela apresentava apatia, cansaço e inapetência. Foram solicitados exames, diagnosticando-se dirofilariose. O hemograma mostrou discreta leucopenia, linfopenia e trombocitopenia. A radiografia de tórax evidenciou bronquitealérgica. O ecocardiograma mostrou a presença de uma forma adulta de Dirofilaria immits. Conclui-se que a dirofilariose induziu alterações hematológicas, porém não graves. O teste rápido foi essencial no auxílio e diagnóstico precoce.(AU)

Heartworm disease is a zoonosis caused by Dirofilaria immitis, a worldwide distribution parasite, considered one of the most pathogenic parasites in dogs. Most of the animals are asymptomatic, however, the disease can affect several. The objective of this study was to report a case of heartworm disease in a female dog. She was apathetic, tired, and inept. Exams were requested, diagnosing heartworm disease. The hemogram showed discrete leukopenia, lymphopenia and thrombocytopenia. Chest x-ray revealed allergic bronchitis. The echocardiogram showed the presence of an adult form of Dirofilaria immits. It was concluded that hear tworm disease induced hematological alterations, but not severe ones. Rapid testing was essential in aiding and early diagnosis.(AU)

Retrospective study of canine heartworm disease with caval syndrome in Grenada, West Indies.

Canine heartworm disease caused by Dirofilaria immitis is an important disease of dogs. The aim of this retrospective study was to estimate the prevalence of canine heartworm disease and evaluate cases of caval syndrome in dogs submitted for necropsy in Grenada. Out of 1617 dogs necropsied over a period of 13 years (2001-2013), 249 were found to be infected with D. immitis; giving an overall prevalence of 15.4% (95% confidence interval, 13.6% to 17.1%). There was no significant difference between male and female dogs with respect to canine heartworm infection (p = 0.3). During this period, the annual prevalence of canine heartworm disease was 22% in 2001 before slightly declining to an average of 18% in 2002-2003 and peaking at 26.8% in 2004-2005. From 2006 onwards, annual prevalence rates have steadily been decreasing; reaching the lowest (9%) in 2013. Among the 249 positive cases, 33 (13.2%) of the dogs had caval syndrome. Caval syndrome cases presented with concurrent clinical signs and were associated with cardio-pulmonary and hepatic gross lesions at necropsy. Aberrant migration of D. immitis was also noted in 2 dogs with caval syndrome. This is the first report which presents the findings of canine heartworm disease with caval syndrome in Grenada.

Canine heartworm disease in Porto Velho: first record, distribution map and occurrence of positive mosquitoes / Dirofilariose canina em Porto Velho: primeiro registro, mapa de distribuicao e ocorrencia de mosquitos positivos

The aim of this study was to make the first report on canine heartworm disease in the state of Rondônia and confirm its transmission in this state. Blood samples were randomly collected from 727 dogs in the city of Porto Velho. The samples were analyzed to search for microfilariae and circulating antigens, using three different techniques: optical microscopy on thick blood smears stained with Giemsa; immunochromatography; and PCR. Mosquitoes were collected inside and outside the homes of all the cases of positive dogs and were tested using PCR to search for DNA of Dirofilaria immitis. Ninety-three blood samples out of 727 (12.8%) were positive according to the immunoassay technique and none according to the thick smear method. Among the 93 positive dogs, 89 (95.7%) were born in Porto Velho. No difference in the frequency of infection was observed between dogs raised indoors and in the yard. PCR on the mosquitoes resulted in only one positive pool. This result shows that the transmission of canine heartworm disease is occurring in the city of Porto Velho and that there is moderate prevalence among the dogs. The techniques of immunochromatography and PCR were more effective for detecting canine heartworm than thick blood smears. The confirmation of canine heartworm disease transmission in Porto Velho places this disease in the ranking for differential diagnosis of pulmonary nodules in humans in Rondônia.

O objetivo deste estudo foi de registrar pela primeira vez a dirofilariose canina no estado de Rondônia e confirmar sua transmissão neste estado. Amostras de sangue de 727 cães foram colhidas aleatoriamente na cidade de Porto Velho. As amostras foram analisadas em busca de microfilárias e antígenos circulantes usando três técnicas diferentes: microscopia ótica de gota espessa corada com Giemsa e imunocromatografia de fluxo lateral e PCR. Mosquitos foram colhidos no domicilio e peridomicílio de todos os casos de cães positivos, estes mosquitos foram testados pela PCR na detecção de DNA de Dirofilaria immitis. Noventa e três das 727 amostras de sangue foram positivas na técnica de imunoensaio (12,8%). Nenhuma amostra foi positiva na gota espessa. Entre os 93 cães positivos, 89 (95,7%) foram nascidos em Porto Velho. Nenhuma diferença na frequencia de infecção foi observada entre cães criados dentro da casa ou no quintal. O PCR dos mosquitos resultou em apenas um pool positivo. Este resultado mostra que a transmissão de dirofilariose canina está ocorrendo na cidade de Porto Velho e a frequência que ocorre nos cães é considerada moderada. As técnicas de imunocromatografia e PCR são mais eficazes na detecção de dirofilariose comparadas a gota espessa. A confirmação de transmissão de dirofilariose canina em Porto Velho, coloca esta doença no ranking de diagnóstico diferencial de nódulos pulmonares em seres humanos em Rondônia.

Canine heartworm disease in Porto Velho: first record, distribution map and occurrence of positive mosquitoes

The aim of this study was to make the first report on canine heartworm disease in the state of Rondônia and confirm its transmission in this state. Blood samples were randomly collected from 727 dogs in the city of Porto Velho. The samples were analyzed to search for microfilariae and circulating antigens, using three different techniques: optical microscopy on thick blood smears stained with Giemsa; immunochromatography; and PCR. Mosquitoes were collected inside and outside the homes of all the cases of positive dogs and were tested using PCR to search for DNA of Dirofilaria immitis. Ninety-three blood samples out of 727 (12.8%) were positive according to the immunoassay technique and none according to the thick smear method. Among the 93 positive dogs, 89 (95.7%) were born in Porto Velho. No difference in the frequency of infection was observed between dogs raised indoors and in the yard. PCR on the mosquitoes resulted in only one positive pool. This result shows that the transmission of canine heartworm disease is occurring in the city of Porto Velho and that there is moderate prevalence among the dogs. The techniques of immunochromatography and PCR were more effective for detecting canine heartworm than thick blood smears. The confirmation of canine heartworm disease transmission in Porto Velho places this disease in the ranking for differential diagnosis of pulmonary nodules in humans in Rondônia.

O objetivo deste estudo foi de registrar pela primeira vez a dirofilariose canina no estado de Rondônia e confirmar sua transmissão neste estado. Amostras de sangue de 727 cães foram colhidas aleatoriamente na cidade de Porto Velho. As amostras foram analisadas em busca de microfilárias e antígenos circulantes usando três técnicas diferentes: microscopia ótica de gota espessa corada com Giemsa e imunocromatografia de fluxo lateral e PCR. Mosquitos foram colhidos no domicilio e peridomicílio de todos os casos de cães positivos, estes mosquitos foram testados pela PCR na detecção de DNA de Dirofilaria immitis. Noventa e três das 727 amostras de sangue foram positivas na técnica de imunoensaio (12,8%). Nenhuma amostra foi positiva na gota espessa. Entre os 93 cães positivos, 89 (95,7%) foram nascidos em Porto Velho. Nenhuma diferença na frequencia de infecção foi observada entre cães criados dentro da casa ou no quintal. O PCR dos mosquitos resultou em apenas um pool positivo. Este resultado mostra que a transmissão de dirofilariose canina está ocorrendo na cidade de Porto Velho e a frequência que ocorre nos cães é considerada moderada. As técnicas de imunocromatografia e PCR são mais eficazes na detecção de dirofilariose comparadas a gota espessa. A confirmação de transmissão de dirofilariose canina em Porto Velho, coloca esta doença no ranking de diagnóstico diferencial de nódulos pulmonares em seres humanos em Rondônia.

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.

Heartworm (Dirofilaria immitis) disease in a Brazilian oncilla (Leopardus tigrinus) / Doença do Verme do Coração (Dirofilaria immitis) em gato-do-mato-pequeno (Leopardus tigrinus) no Brasil

Heartworm disease is caused by the intravascular nematode Dirofilaria immitis, a pathogen of public health importance usually associated to domestic dogs and cats, and to a lesser extend to other mammal species. The oncilla (Leopardus tigrinus) is a threatened neotropic felid species that naturally occurs in Brazil. Here, we report the encounter of adult and larval stages of heartworms in a female specimen of L. tigrinus, probable of free-ranging origin, from Ubatuba, São Paulo, Brazil, which died showing clinical signals compatible with heartworm disease. This was the first reported case of D. immitis infection and associated disease in L. tigrinus, also suggesting that the oncilla acted as a definitive host for this parasite. The present findings confirmed D. immitis as a pathogenic agent for this felid species, thus supporting the recommendation for the inclusion of diagnostic testing for this pathogen in routine health screening procedures for captive and free-ranging oncillas in Brazil, especially in those localities where climate conditions support the occurrence of the parasite. Potential reservoirs as oncillas are established beyond the reach of veterinary care, thus representing a continuing risk for domestic animals and humans acquiring heartworm infection. We encourage further serologic and molecular studies aiming to establish D. immitis prevalences in L. tigrinus and other wild carnivores in the region of Ubatuba, as well as ecological and veterinary studies to access the role of this pathogen for the survival of this threatened felid species.

A doença do verme do coração é causada pelo nematódeo intravascular Dirofilaria immitis, um patógeno de importância em Saúde Pública geralmente associado a cães e gatos domésticos e, em menor extensão, a outras espécies de mamíferos. O gato-do-mato-pequeno (Leopardus tigrinus) é uma espécie ameaçada de felídeo neotropical que ocorre naturalmente no Brasil. Aqui relatamos o encontro de estágios adultos e larvais de vermes do coração em uma fêmea de L. tigrinus, provavelmente de vida livre e originária de Ubatuba, São Paulo, Brasil, que veio a óbito demonstrando sinais clínicos compatíveis desta doença. Este é o primeiro caso relatado de infecção e doença associada com D. immitis em L. tigrinus, sugerindo também que o gato-do-mato-pequeno agiu como hospedeiro definitivo para este parasita. Estes achados confirmaram que D. immitis é um agente patogênico para esta espécie de felino, sugerindo a recomendação para a inclusão de testes diagnósticos para este patógeno em procedimentos rotineiros de avaliação da saúde para gatos-do-mato-pequenos mantidos em cativeiro e de vida livre no Brasil, especialmente em localidades onde as condições climáticas permitam a ocorrência do parasita. Os gatos-do-mato-pequenos são potenciais reservatórios da D. immitis, mas vivem fora do alcance veterinário, representando desta forma um risco contínuo para animais domésticos e humanos. Encorajamos a realização de outros estudos epidemiológicos a fim de estabelecer as prevalências de infecção por D. immitis em L. tigrinus e outros carnívoros selvagens na região de Ubatuba, assim como estudos ecológicos e médicos veterinários para se acessar o papel deste patógeno para a sobrevivência desta espécie ameaçada de felídeo.

Heartworm (Dirofilaria immitis) disease in a Brazilian oncilla (Leopardus tigrinus) / Doença do Verme do Coração (Dirofilaria immitis) em gato-do-mato-pequeno (Leopardus tigrinus) no Brasil

Heartworm disease is caused by the intravascular nematode Dirofilaria immitis, a pathogen of public health importance usually associated to domestic dogs and cats, and to a lesser extend to other mammal species. The oncilla (Leopardus tigrinus) is a threatened neotropic felid species that naturally occurs in Brazil. Here, we report the encounter of adult and larval stages of heartworms in a female specimen of L. tigrinus, probable of free-ranging origin, from Ubatuba, São Paulo, Brazil, which died showing clinical signals compatible with heartworm disease. This was the first reported case of D. immitis infection and associated disease in L. tigrinus, also suggesting that the oncilla acted as a definitive host for this parasite. The present findings confirmed D. immitis as a pathogenic agent for this felid species, thus supporting the recommendation for the inclusion of diagnostic testing for this pathogen in routine health screening procedures for captive and free-ranging oncillas in Brazil, especially in those localities where climate conditions support the occurrence of the parasite. Potential reservoirs as oncillas are established beyond the reach of veterinary care, thus representing a continuing risk for domestic animals and humans acquiring heartworm infection. We encourage further serologic and molecular studies aiming to establish D. immitis prevalences in L. tigrinus and other wild carnivores in the region of Ubatuba, as well as ecological and veterinary studies to access the role of this pathogen for the survival of this threatened felid species.(AU)

A doença do verme do coração é causada pelo nematódeo intravascular Dirofilaria immitis, um patógeno de importância em Saúde Pública geralmente associado a cães e gatos domésticos e, em menor extensão, a outras espécies de mamíferos. O gato-do-mato-pequeno (Leopardus tigrinus) é uma espécie ameaçada de felídeo neotropical que ocorre naturalmente no Brasil. Aqui relatamos o encontro de estágios adultos e larvais de vermes do coração em uma fêmea de L. tigrinus, provavelmente de vida livre e originária de Ubatuba, São Paulo, Brasil, que veio a óbito demonstrando sinais clínicos compatíveis desta doença. Este é o primeiro caso relatado de infecção e doença associada com D. immitis em L. tigrinus, sugerindo também que o gato-do-mato-pequeno agiu como hospedeiro definitivo para este parasita. Estes achados confirmaram que D. immitis é um agente patogênico para esta espécie de felino, sugerindo a recomendação para a inclusão de testes diagnósticos para este patógeno em procedimentos rotineiros de avaliação da saúde para gatos-do-mato-pequenos mantidos em cativeiro e de vida livre no Brasil, especialmente em localidades onde as condições climáticas permitam a ocorrência do parasita. Os gatos-do-mato-pequenos são potenciais reservatórios da D. immitis, mas vivem fora do alcance veterinário, representando desta forma um risco contínuo para animais domésticos e humanos. Encorajamos a realização de outros estudos epidemiológicos a fim de estabelecer as prevalências de infecção por D. immitis em L. tigrinus e outros carnívoros selvagens na região de Ubatuba, assim como estudos ecológicos e médicos veterinários para se acessar o papel deste patógeno para a sobrevivência desta espécie ameaçada de felídeo.(AU)

Freqüência de dirofilariose canina (D. immitis) em algumas regiões do Estado de São Paulo por meio da detecção de antígenos circulantes

The frequency of canine heartworm disease was determined in 310 dogs (158 males and 152 females) from São Paulo city (154) and several towns along the São Paulo state coast (156). The survey was carried out through the Knott's technique (direct presence of microfilariae in the blood) and ELISA for soluble circulating antigen detection. Twenty five (8.0%) samples were positive to D. immitis using both methods being 6 dogs (3.9%) from the city and 19 (12.2%) from the coastal area. Nineteen dogs (6.1%) were positive to the Knott's technique (4 from the city and 15 from the coastal area) and 12 dogs (3.9%) to the ELISA (4 from the city and 8 from the coastal area); six dogs (1.9%) were positive for both methods being two from the city and four from the coastal area. The frequency of positive dogs by the Knott's technique in the coastal area was higher than that in São Paulo city (P 0.05), but equivalent frequency was found in dogs from both areas when the ELISA test was used. Higher number of dogs with a patent infection (microfilaremic) was found than those with occult infection (amicrofilaremic). This survey has shown that the dogs were not infected with high frequency probably because the studied areas were not hiperenzootic endemic (higher than 10% of frequency).

Determinou-se a freqüência da dirofilariose canina em 310 (158 machos e 152 fêmeas) cães oriundos da cidade de São Paulo (154) e do litoral paulista (156). O levantamento foi realizado por meio da técnica de Knott (pesquisa de microfilárias) e do teste de ELISA para detecção de antígenos circulantes solúveis. Vinte e cinco (8,0%) amostras apresentaram-se positivas utilizando-se os dois métodos para D. immitis, seis (3,9%) da cidade e 19 (12,2%) da área litorânea. Detectou-se positividade ao Knott em 19 (6,1%) amostras, quatro de São Paulo e 15 do litoral, e 12 (3,9%) reagentes ao ELISA, quatro de São Paulo e oito do litoral; seis (1,9%) amostras foram positivas pelos dois métodos, duas em São Paulo e quatro no litoral. A percentagem de cães positivos pelo método de Knott no litoral foi maior do que em São Paulo (P 0,05), porém ao teste de ELISA os casos positivos foram eqüivalentes. A infecção patente (microfilarêmica) prevaleceu sobre a infecção oculta (amicrofilarêmica), portanto não houve grande freqüência de cães infectados provavelmente por não se tratar de áreas de alta endemicidade, onde a ocorrência é maior que 10%.