Epidemiological analysis of Dirofilaria immitis (Spirurida: Onchocercidae) infecting pet dogs (Canis lupus familiaris, Linnaeus, 1758) in Baixada Fluminense, Rio de Janeiro.

Dirofilaria immitis infection is routinely detected in dogs during veterinary care in tropical and subtropical regions worldwide. Parasitological tests for the detection of this infection are routinely performed only in areas with a high prevalence. Baixada Fluminense, a region in Rio de Janeiro, was considered heartworm-free until local veterinarians began to receive blood exams results indicating the presence of microfilariae (MF). A laboratory database was hence used to collect data from 2017 to 2020 to understand the extent of spread of the parasite in this area. The results of complete blood count analysis and MF or heartworm antigen detection tests conducted on canine samples sent from veterinary clinics in Baixada Fluminense (Magé, Duque de Caxias, Guapimirim, Nova Iguaçu, and São João de Meriti municipalities) were included. In total, the results of 16,314 hematological tests were considered. The overall prevalence of D. immitis was 3.4% (554/16,314), considering that only one test result was obtained per animal on the same day. This study is highly relevant because it indicates the spreading geographic distribution of the worms, heightens awareness among local health professionals and the general population, and encourages compliance with prophylactic measures to prevent further spread of parasite.

Prevention of heartworm infection in dogs using a combination of moxidectin, imidacloprid and praziquantel: evidence from a randomized clinical trial.

The aim of this study was to evaluate the efficacy of a topical combination of moxidectin 3.5%, imidacloprid 10% and praziquantel 10% for the prevention of Dirofilaria immitis (Leidy, 1856) infection in dogs. For this purpose, a randomized and controlled clinical trial was conducted between August 2021 and October 2022, in the municipality of Goiana, state of Pernambuco, north-eastern Brazil, where heartworm is highly prevalent. Of the 213 dogs initially sampled (baseline), 68 (31.9%) were positive for adult antigens (SNAP 4Dx Plus, Idexx) and/or microfilariae (modified Knott's test). On day 0, 140 negative dogs were randomly included in the treatment and control groups, 70 animals each. During the study, 60 dogs (34 treated and 26 untreated) were removed for different reasons. At the end of the study (day 360 ± 2), 36 treated and 44 untreated were sampled and included in the efficacy calculation. The efficacy against the development of adults and microfilariae was 84.7%, with only one treated dog being positive for adult antigens but negative for microfilariae. On the other hand, eight untreated dogs were positive for adult antigens and/or microfilariae, resulting in a significant difference in the number of positives between groups (Chi-square test = 4.706, df = 1, P = 0.0301). Remarkably, the efficacy against the appearance of D. immitis microfilariae was 100% (i.e., all treated dogs negative) and three untreated dogs were positive for microfilariae. The topical combination of moxidectin 3.5%, imidacloprid 10% and praziquantel 10% significantly reduced the risk of D. immitis infection in treated dogs as compared with untreated dogs, in a highly endemic area in north-eastern Brazil.

Frequency of Dirofilaria immitis infection in blood donor dogs of the Rio de Janeiro state.

Dirofilariasis, a parasitic disease caused by the nematode Dirofilaria immitis, commonly known as heartworm, primarily inhabits the pulmonary artery and right heart of dogs and other animals. The disease is transmitted through diptera, predominantly from the Culex, Aedes, and Anopheles genera. Dirofilariasis is cosmopolitan in nature, endemic in coastal regions and tropical climates. Factors such as temperature, humidity, vector density, and the presence of definitive hosts significantly contribute to the spread of this parasitic disease. In the state of Rio de Janeiro, a prevalence of 58.6% of D. immitis infected animals has been recorded in municipalities like Niterói. Given that blood transfusions are routine clinical procedures and blood bags are not always accurately evaluated, an investigation into D. immitis infection in blood donor dogs from the metropolitan region of Rio de Janeiro was conducted. A total of 1044 blood donor dog files from a blood bank in Niterói, RJ, collected from January 2019 to December 2022, were analyzed. These samples, originating from kennels in various municipalities in the Metropolitan Region, were tested for the presence of microfilariae through direct examination using tubes and microhematocrit evaluated in optical microscopy. Additionally, the search for antigens was conducted using the enzyme-linked immunosorbent assay technique. Out of the 1044 records evaluated, 17.8% (186/1044) were positive for heartworm infection, with 2% (21/1044) samples positive for microfilariae and 14.8% (154/1044) positive for D. immitis antigens. The high prevalence rate indicates that canine D. immitis infection remains prevalent in the state of Rio de Janeiro, necessitating effective guidelines for prescribing preventive medications by veterinarians and an increase in epidemiological surveillance in the region.

A dirofilariose é uma parasitose determinada pelo nematóide Dirofilaria immitis, que tem como habitat artéria pulmonar e coração direito de canídeos e outros animais, sendo por isso conhecido popularmente como verme do coração. A transmissão da parasitose ocorre por meio de dípteros principalmente dos gêneros Culex, Aedes e Anopheles. A dirofilariose é considerada cosmopolita, sendo endêmica em regiões litorâneas e de clima tropical. A temperatura, a umidade, a densidade de vetores e a presença de hospedeiros definitivos são considerados os principais fatores que contribuem para a propagação da parasitose. No estado do Rio de Janeiro, alguns municípios como Niterói, já foi registrada uma prevalência de 58.6% de animais infectados por D. immitis. Como as transfusões de sangue são procedimentos clínicos rotineiros e as bolsas de sangue nem sempre são avaliadas corretamente, decidiu-se investigar a infecção por D. immitis em cães doadores de sangue da região metropolitana do estado do Rio de Janeiro. Foram analisados 1044 prontuários de cães doadores de sangue de um banco de sangue localizado em Niterói, RJ, obtidos no período de janeiro de 2019 a dezembro de 2022. As amostras foram provenientes de canis localizados em diferentes municípios da Região Metropolitana, e testadas para presença de microfilárias por meio de exame direto utilizando-se tubos e microhematócrito avaliados em microscopia óptica e através da realização da pesquisa de antígenos utilizando-se a técnica de ELISA. Das 1044 fichas avaliadas, 17.8% (186/1044) das amostras foram positivas para infecção pelo verme do coração, sendo 2% (21/1044) positivas para presença de microfilárias e 14.75% (154/1044) positivas para presença de antígenos de D. immitis. A alta taxa de prevalência encontrada permite concluir que a infecção canina por D. immitis ainda apresenta alta prevalência no estado do Rio de Janeiro, exigindo orientações efetivas para a prescrição de medicamentos preventivos por médicos veterinários e aumento da vigilância epidemiológica na região.

Dirofilaria immitis in pet dogs from the metropolitan area of the Colombian Caribbean.

A cross-sectional study was carried out to determine the frequency and factors associated with Dirofilaria immitis infection in pet dogs in the metropolitan area of the Colombian Caribbean (northern Colombia). A total of 173 dogs were analyzed by a commercial rapid immunochromatographic test (RIT) and a nested PCR of the cytochrome oxidase subunit I gene, in parallel. Ninety-two (53.2%) of the dogs showed positive results to the RIT, while 59 (34.1%) animals had D. immitis DNA by PCR. Positivity to one or both diagnostic techniques was detected in 104 (60.1%; CI95%: 53.8-67.4) of the sampled dogs. In PCR-positive dogs, phylogenetic analyses evidenced high nucleotide identity (100%) with sequences previously obtained from mosquitoes, dogs and other mammals in different countries. Exercise intolerance (p = 0.002; OR: 2.33; CI95%: 1.37-3.96) and thrombocytopenia (p = < 0.001; OR: 1.95; CI95%: 1.11-3.43) were the main factors associated with D. immitis infection in dogs. The high frequency of D. immitis in dogs indicates a wide distribution of this parasite in the metropolitan area of the Colombian Caribbean, which can be of animal and public health concern. Our results highlight the need to combine different methods to increase the diagnostic accuracy of D. immitis.

Dogs infected by Dirofilaria immitis: a threat to the health of human and non-human animals in Rio de Janeiro, Brazil.

This study aimed to investigate the presence of Dirofilaria immitis microfilaremia in dogs from two regions of the state of Rio de Janeiro, Brazil, where heartworm infections are highly prevalent. Blood samples were collected from dogs aged > 12 months, independent of the use of preventatives. All samples obtained and analyzed using Knott's modified test by the investigators. A total of 133 blood samples were tested, and D. immitis microfilariae were detected in 29 of them, resulting in an occurrence of 21.8%. The percentage of dogs with microfilaremia detected raises concerns for pet families, one health professionals, and small animal practitioners. Microfilaremic dogs are the richest source of infection for the mosquitoes, increasing the risk of transmission. Therefore, the stakeholders in One Health must raise concerns regarding the health of wild animals, as wild canids and other species of wild animals are exposed to the risk of D. immitis infection. In addition, humans can get infected and develop human pulmonary dirofilariasis. In conclusion, the presence of dogs with microfilaremia potentiates opportunities for D. immitis transmission, exposing all animals, wild or domestic, human or non-human to the disease.

Este estudo objetivou investigar a presença de cães portadores de microfilemia da espécie Dirofilaria immitis em duas áreas do estado do Rio de Janeiro, Brasil onde a infecções por vermes do coração são altamente prevalescentes. Amostras de sangue foram obtidas de cães com mais de 12 meses de idade, independentemente do uso de preventivos. Todas as amostras foram obtidas e analisadas pelo grupo do estudo utilizando-se o teste de Knott modificado. Um total de 133 amostras foi testado e microfilárias de D. immitis foram detectadas em 29 amostras, resultando em uma ocorrencia de 21,8%. A porcentagem de cães com microfilaremia detectada gera preocupações para as famílias de animais de estimação, para profissionais da saúde única e para clínicos de pequenos animais. Cães microfilarêmicos são a mais rica fonte de infecção para mosquitos, aumentando o perigo de transmissão. Assim, atores de todos os segmentos sociais com interesse na saúde única devem incluir a saude de animais selvagens em suas preocupações, uma vez que canideos selvagens e outras espécies de animais selvagens são expostos ao desafio da infecção por D.immitis. Além disso, seres humanos podem se tornar infectados e desevolver dirofilariose pulmonar humana. Em conclusão, a presença de cães microfilarêmicos potencializa as oportunidades de trasmissão de D. immitis, expondo todos os animais, selvagens ou domesticos, humanos ou não humanos à doença.

Dirofilaria immitis parasite infection in cats: first case reported in the Legal Amazon region, Brazil: case report / Infecção por Dirofilaria immitis em gato: primeiro registro na região da Amazônia Legal, Brasil: relato de caso

A case of infection with Dirofilaria immitis in a cat is reported here with clinical signs of apathy, anorexia, dyspnea, polypnea, slight dehydration and pale mucus membranes. The radiographic examination showed cardiomegaly, lobar arteries dilation of the cranial lobes and tortuosity, enlargement of the caudal lobar arteries. In the right lobe of the lung parenchyma, interstitial pulmonary opacification tending to alveolar opacification was seen. The clinical signs, the movements, and the morphology of the microfilariae in the direct examination of fresh blood, peripheral blood smear and Knott's modified test supported the diagnosis. We alert to the need for clinicians to consider feline heartworm diseases as a differential diagnosis in endemic areas when cats show respiratory signs.

Descreve-se um caso de infecção por Dirofilaria immitis em gato com sinais clínicos de apatia, anorexia, dispneia, polipneia, leve desidratação e mucosas pálidas. O exame radiográfico demonstrou cardiomegalia, dilatação da artéria lobar cranial e tortuosidade, alargamento dos lobos caudais da artéria lobar. No lobo direito do parênquima pulmonar, opacificação pulmonar intersticial tendendo à opacificação foi observada. O diagnóstico foi baseado nos sinais clínicos, nos movimentos e na morfologia das microfilárias detectadas no exame de sangue a fresco, no esfregaço de sangue periférico e no teste de Knott modificado. Alertou-se para a necessidade de os clínicos considerarem a dirofilariose felina como diagnóstico diferencial em áreas endêmicas quando os gatos apresentam sinais respiratórios.

Clinical and blood count findings in dogs naturally infected with Dirofilaria immitis.

Dirofilaria immitis is a nematode that infects canids worldwide as well as other mammalian species, including humans. Worms and dogs are well adapted to one another, making dogs the best urban host for the parasite. Nevertheless, 30% of dogs do not sufficiently present microfilaremia, that is, the low larval load impairs transmission by mosquitoes and diagnosis by its detection in the blood samples. Therefore, the canine diagnosis must always include a microfilaria test and serological tests to detect adult worm antigens. To describe the clinical findings in naturally infected dogs in Rio de Janeiro, 34 dogs were included in the study. All dogs were evaluated for history, anamnesis, physical examination, complete blood count (CBC), D. immitis testing for antigens (ELISA test SNAP 4Dx Plus®), and microfilarial burden. The most frequent complaint from the owners was coughing (14.7%, 5/34). The most common CBC finding was eosinophilia (29.4%), followed by thrombocytopenia (26.5%) and neutrophilia (14.7%). Of the 34 animals, 91.2% were microfilaremic, with a mean count of 11.939 microfilaria/mL. Veterinarians working in areas endemic to D. immitis should always undergo screening tests and pulmonary auscultation, and increased expiratory sounds, even in the absence of coughing, can be considered a sign of the disease, along with eosinophilia, thrombocytopenia, and neutrophilia.

Dirofilaria immitis, é um nematoide que infecta canídeos em todo o mundo, bem como outras espécies de mamíferos, incluindo humanos. Os vermes e os cães estão bem adaptados um ao outro, tornando os cães o melhor hospedeiro urbano para o parasita. Contudo, 30% dos cães não apresentam microfilaremia, prejudicando a transmissão pelos mosquitos e o diagnóstico por detecção de larvas em amostras de sangue. Portanto, o diagnóstico canino deve incluir sempre a pesquisa de microfilárias e sorologia para detecção do antígeno do verme adulto. Com o objetivo de descrever os achados clínicos de cães naturalmente infectados no Rio de Janeiro, 34 cães foram incluídos. Todos os cães foram avaliados por histórico, anamnese, exame físico, hemograma completo (CBC), teste de antígenos, pesquisa e contagem de microfilárias de D. immitis. A queixa mais frequente dos responsáveis foi a tosse (14,7% - 5/34). O achado de hemograma mais comum foi eosinofilia (29,4%), seguido de trombocitopenia (26,5%) e neutrofilia (14,7%). Dos 34 animais, 91,2% eram microfilarêmicos com contagem média de 11.939 microfilárias/mL. Os veterinários que atuam em áreas endêmicas de D. immitis devem sempre realizar exames de triagem e ausculta pulmonar, pois mesmo na ausência de tosse, sons expiratórios aumentados podem ser considerados um sinal da doença, assim como eosinofilia, trombocitopenia e neutrofilia.

How does Dirofilaria immitis infection impact the health of dogs referred to cardiology care.

Dirofilaria immitis is a nematode that can cause a disease that may present clinical signs from severe to absent. When dogs are symptomatic, the clinical signs are cardiorespiratory and nonspecific, which may be misleading. This study aimed to demonstrate the clinical presentations to cardiac care by evaluating 26 dogs subjected to clinical examination, complete blood count (CBC), specific tests for D. immitis infection, chest radiography, and echocardiography. Among them, 11 (42.3%) dogs were infected and 15 (57.7%) were non-infected. Most dogs presented with coughing (65.4%) and abnormal lung sounds (81%) independent of infection. Murmur at the tricuspid focus was present in 26.9% of the dogs, of which 57.1% were infected. Echocardiography revealed tricuspid regurgitation in 30.8% of the dogs and pulmonary regurgitation in 46.1%, of which 37.5% and 50% were infected, respectively. Worms were detected by echocardiography in 45.5% of the infected dogs. The x-rays showed that the bronchial pattern was present in 45.5% of the infected dogs and in 46.7% of the non-infected dogs. The interstitial pattern was present in 18.2% of the infected animals, in contrast to 6.7% of the non-infected dogs. The CBC results for all dogs were within the reference range, except for platelets. Although similar, the percentage of dogs with thrombocytopenia was higher among infected dogs (36.4%) than among the non-infected (6.7%). These results reinforce that due to the non-specific signs of infection, it is mandatory to perform parasitological assays when evaluating dogs presenting with cardiopulmonary signs.

Dirofilaria immitis, é um nematoide que pode causar sinais clínicos de graves a ausentes. Quando os cães são sintomáticos, os sinais clínicos são cardiorrespiratórios e inespecíficos, o que pode confundir com outras doenças. Com o objetivo de descrever a apresentação clínica de cães atendidos em um serviço de cardiologia e doenças respiratórias, após consentimento dos tutores, 26 pacientes foram submetidos a exame clínico, hemograma, exames específicos para infecção por D. immitis, radiografia de tórax e ecocardiografia. Entre esses cães, 11 estavam infectados (42,3%) e 15 não infectados (57,7%). A maioria dos cães apresentou tosse (65,4%) e sons pulmonares anormais (81%) independentemente da infecção. O sopro no foco tricúspide estava presente em 26,9% dos cães, sendo 57,1% infectados. A ecocardiografia mostrou insuficiência tricúspide em 30,8% dos cães e insuficiência pulmonar em 46,1%, sendo 37,5% e 50% infectados, respectivamente. Parasitos foram detectados pela ecocardiografia em 45,5% dos cães infectados. As radiografias mostraram que o padrão brônquico estava presente em 45,5% dos cães infectados e em 46,7% dos não infectados. O padrão intersticial esteve presente em 18,2% dos infectados e em 6,7% dos não infectados. Os resultados do hemograma de todos os cães estavam dentro do intervalo de referência para todas as células, exceto plaquetas. Embora semelhante, a porcentagem de cães com trombocitopenia foi maior entre os cães infectados (36,4%), do que entre os livres de infecção (6,7%). Esses resultados reforçam que, devido aos sinais inespecíficos da infecção, é obrigatória a realização de ensaios parasitológicos na avaliação de cães que apresentem sinais cardiopulmonares.

Prevalence and risk factors for Dirofilaria immitis in dogs from Laguna, Santa Catarina, Brazil.

Dirofilaria immitis is a nematode found worldwide and able to infect several species, such as dogs, cats and, under rare circumstances, humans. In Brazil, most of the infections are related to coastal areas. The present study aimed at determining Dirofilaria immitis prevalence and evaluating the possible risk factors for infection in dogs, in Laguna, Santa Catarina, Brazil. Blood samples from 238 dogs were collected and a questionnaire was applied to the owners in order to obtain general information about the animals (age, gender, breed, coat color, home location (region), the use of dewormer/ectoparasiticide drugs, habits and behavior, roaming, insect control and the owner's knowledge about the disease). Samples were processed by blood smear techniques, modified Knott's test, immunochromatographic assay and PCR. Data were statistically analyzed by χ2 and OR. 4.62% was the overall prevalence of canine dirofilariasis and the suburb of Bananal, in Laguna, showed the highest prevalence (18.8%) when comparing with other regions (p < 0.05). However, there was no other significant factor related to the prevalence of D. immitis infection. Thus, the research have confirmed the presence of D. immitis in Laguna region, with a high prevalence in Bananal suburb, a dense forested area.

Granuloma caused by Acanthocheilonema spp. in a canine: case report / [Granuloma por Acanthocheilonema spp. em um cão: relato de caso]

A canine patient, 13-year-old mixed breed male, 24kg, was seen at a private clinic in the city of Guayaquil, Ecuador. The main reason for consultation was the evaluation of a mass in the right knee and neck that had previously been cytologically diagnosed of neoplastic origin by another team of veterinarians through fine needle puncture and cytology. The contacts were asymptomatic. At the time of the consultation, a detailed exploration and complementary methods were performed that included hematological and urinary exams, mass cytology, serological test, chest radiography and biopsy for further histopathological study. The final diagnosis was a cutaneous granuloma due to microfilariae of Acanthocheilonema spp. and its subsequent surgical and medical treatment with excellent results. The canine heartworm is a cosmopolitan disease caused by nematodes of the genus Dirofilaria, with D. immitis being the best-known species. Less frequently, the species Acanthocheilonema spp., found in this patient, is also reported in Americas, with little knowledge about it. This is the first report of its kind hoping that it will serve as a basis for future studies.

Foi atendido, em uma clínica particular, na cidade de Guaiaquil, Equador, um paciente canino, sem raça definida, de 13 anos de idade, macho, não castrado, de 24kg. O motivo da consulta foi a avaliação de uma massa em região de articulação de joelho direito e de pescoço, que havia sido previamente diagnosticada como de origem neoplásica por outra equipe de médicos veterinários, mediante punção por agulha fina e citologia. Os contactantes eram assintomáticos. No momento da consulta, realizaram-se detalhadas avaliações clínica e complementar, que incluíram exames hematológicos, urinálise, citologia da massa, teste sorológico, radiografia torácica e biopsia para posterior estudo histopatológico. O diagnóstico final foi granuloma cutâneo por microfilária de Acanthocheilonema spp., para o qual os tratamentos clínico e cirúrgico apresentaram excelentes resultados. A dirofilariose é uma enfermidade cosmopolita causada por nematódeos do gênero Dirofilaria, sendo a espécie D. immitis a mais conhecida. Em menor frequência, a espécie Acanthocheilonema spp. encontrada neste paciente é também relatada na América, existindo pouco conhecimento a seu respeito. Este é o primeiro relato de caso sobre este tema e espera-se que sirva como base para futuros estudos.

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.

Infection with Dirofilaria immitis and Other Infections in Cats and Dogs from Rio de Janeiro, Brazil: The Need for Prophylactic Enforcement.

PURPOSE: Dirofilaria immitis, a mosquito-borne nematode that primarily infects dogs, can equally infect cats. Although there have been numerous studies on canine heartworm prevalence in Brazil, there have been few studies on feline infections. Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are both life-threatening retroviruses transmitted directly between cats. Infections with Ehrlichia spp. and Anaplasma spp. are highly prevalent among dogs in Brazil, with Rhipicephalus sanguineus being the main vector for both bacteria. This study aimed to gather information on these infections among dogs and cats in the metropolitan area of Rio de Janeiro by performing rapid point-of-care tests for prophylactic enforcement. METHODS: Surplus samples of serum or plasma from private laboratories were tested by enzyme-linked immunosorbent assay (ELISA) (SNAP Feline Triple Test or SNAP 4Dx Plus Test). RESULTS: The prevalence of heartworm disease was 7% among dogs and 0.9% among cats, the latter being 12.9% of the former. The prevalence of FIV and FeLV was 4.3 and 11.9%, respectively. Among dogs, the seroprevalence of Ehrlichia spp. and Anaplasma spp. was 27.1 and 9.8%, respectively, and Borrelia burgdorferi was not detected. CONCLUSION: Given that such infections circulate among pets, prophylactic measures should be encouraged by small animal practitioners.

Report of Dirofilaria immitis infection with acute cardiopulmonary complications in a cat from Northeastern Brazil / Relato de infecção por Dirofilaria immitis com complicações cardiopulmonares agudas em um gato no Nordeste do Brasil

Dirofilariasis is a zoonotic disease caused by Dirofilaria immitis, a nematode found mainly in the pulmonary artery and right chambers of the heart, lungs, and large vessels of dogs. This parasitism also occasionally occurs in cats, causing an amicrofilaremic and asymptomatic infection, resulting in severe illness and rapid death. In this case report, it was described acute clinical signs and histopathological alterations in a domestic cat with heartworm disease from the city of Mossoró, the Rio Grande do Norte, Brazil. The nematode species, D. immitis, was confirmed by morphological and molecular analyses. This is the first documented and full report of feline heartworm disease in northeastern Brazil.(AU)

A dirofilariose é uma doença zoonótica causada por Dirofilaria immitis, um nematódeo que parasita cães, principalmente a artéria pulmonar e as câmaras direitas do coração, pulmões e grandes vasos. Este parasita também ocorre ocasionalmente em gatos, geralmente causando uma infecção amicrofilarêmica e assintomática, que pode resultar em doença grave e morte rápida. Neste relato de caso, são apresentados os sinais clínicos agudos e alterações histopatológicas em um gato doméstico do município de Mossoró, Rio Grande do Norte, Brasil, com dirofilariose. A espécie de nematóide, D. immitis, foi confirmada por análises morfológicas e moleculares. Este é o primeiro relato documentado e completo de dirofilariose felina no Nordeste do Brasil.(AU)

Report of Dirofilaria immitis infection with acute cardiopulmonary complications in a cat from Northeastern Brazil / Relato de infecção por Dirofilaria immitis com complicações cardiopulmonares agudas em um gato no Nordeste do Brasil

Dirofilariasis is a zoonotic disease caused by Dirofilaria immitis, a nematode found mainly in the pulmonary artery and right chambers of the heart, lungs, and large vessels of dogs. This parasitism also occasionally occurs in cats, causing an amicrofilaremic and asymptomatic infection, resulting in severe illness and rapid death. In this case report, it was described acute clinical signs and histopathological alterations in a domestic cat with heartworm disease from the city of Mossoró, the Rio Grande do Norte, Brazil. The nematode species, D. immitis, was confirmed by morphological and molecular analyses. This is the first documented and full report of feline heartworm disease in northeastern Brazil.(AU)

A dirofilariose é uma doença zoonótica causada por Dirofilaria immitis, um nematódeo que parasita cães, principalmente a artéria pulmonar e as câmaras direitas do coração, pulmões e grandes vasos. Este parasita também ocorre ocasionalmente em gatos, geralmente causando uma infecção amicrofilarêmica e assintomática, que pode resultar em doença grave e morte rápida. Neste relato de caso, são apresentados os sinais clínicos agudos e alterações histopatológicas em um gato doméstico do município de Mossoró, Rio Grande do Norte, Brasil, com dirofilariose. A espécie de nematóide, D. immitis, foi confirmada por análises morfológicas e moleculares. Este é o primeiro relato documentado e completo de dirofilariose felina no Nordeste do Brasil.(AU)

Efficacy of semi-annual therapy of an extended-release injectable moxidectin suspension and oral doxycycline in Dirofilaria immitis naturally infected dogs.

BACKGROUND: Dirofilaria immitis is a life-threatening nematode spreading globally. Arsenical treatment is currently recommended for removal of adult worms. However, arsenical treatment is not available in some countries, and there are dogs that cannot tolerate the rapid kill of adult worms; therefore, alternative adulticide slow-kill treatments are needed. Criticisms against the use of these alternative protocols include the potential for allowing disease to progress and for the development of ML-resistant worms. METHODS: The efficacy of a protocol that includes semi-annual doses (i.e. every 6 months) of commercially available extended-release injectable moxidectin suspension (ProHeart® SR-12) with 30-day oral administration of doxycycline was studied in 20 dogs with naturally occurring D. immitis infections. Each dog received treatment with ProHeart® SR-12 (0.5 mg moxidectin/kg) by subcutaneous injection and oral doxycycline (10 mg/kg/bid × 30 days) every 6 months until two consecutive negative antigen test results were obtained. Pulmonary and cardiac evaluations were performed by radiographic and echocardiographic parameters. Physical examinations, complete blood counts, clinical chemistry profiles, microfilariae and antigen tests were performed periodically. RESULTS: At enrollment, all dogs were positive for D. immitis antigen and 18 were microfilaremic. On day 30, microfilaremia counts decreased, and all dogs became amicrofilaremic by day 150. On day 180, 11 dogs were antigen-negative, and 7 more became negative by day 360. The two remaining antigen-positive dogs converted to negative by day 540 or 810. All antigen tests performed 180 days after the first negative test were negative. There was no decline in cardiac performance of the dogs throughout the study. Overall, pulmonary clinical conditions, presence of worms by echocardiography, and enlargement of caudal and main pulmonary arteries improved after treatment. Physical examinations, complete blood count results, and clinical chemistry profiles were within normal reference values. Respiratory conditions were improved, no damage to the heart was observed, and the treatment protocol was well tolerated by the animals. CONCLUSIONS: This alternative adulticide treatment was efficacious and well tolerated in naturally infected dogs. The injectable formulation provides the advantage of having veterinarians able to administer, monitor, and assess the efficacy and condition of the dog throughout the treatment and post-treatment periods.

Heartworm control in Grenada, West Indies: Results of a field study using imidacloprid 10% + moxidectin 2.5% and doxycycline for naturally-acquired Dirofilaria immitis infections.

Canine heartworm disease (CHD) results from infection with Dirofilaria immitis and while it is of global concern, it is most prevalent in tropical climates where conditions support the parasite and vector life cycles. Melarsomine dihydrochloride is the sole treatment for CHD recommended by the American Heartworm Society. However, in cases where cost or access to melarsomine precludes treatment of an infected dog, therapeutic alternatives are warranted. This randomized, controlled field study evaluated the adulticidal efficacy of a combination therapeutic protocol using 10 % imidacloprid + 2.5 % moxidectin spot-on and a single 28-day course of doxycycline and compared with that of a 2-dose melarsomine dihydrochloride protocol. Of 37 naturally-infected domestic dogs with class 1, 2 or early class 3 CHD enrolled in the study, 30 were evaluated for a minimum of 12 months. Seven dogs were withdrawn due to canine ehrlichiosis, non-compliance, or wrongful inclusion. Dogs were randomly assigned to a control (CP, n = 15) or investigational (IVP, n = 15) treatment group. CP dogs received two injections of melarsomine dihydrochloride (2.5 mg/kg) 24 -hs apart and maintained on monthly ivermectin/pyrantel. IVP dogs were treated with oral doxycycline (10 mg/kg twice daily for 28 days) and topical 10 % imidacloprid + 2.5 % moxidectin once monthly for 9 months. Dogs were evaluated up to 18 months - monthly for the first 9 months, then every 3 months. Parasiticidal efficacy was based on antigen status using the IDEXX PetChek® 34 Heartworm-PF Antigen test. By month 18, antigen was not detected in any study dog except one from the IVP group. One other IVP dog was persistently antigenemic and treated with melarsomine at month 12 according to the initial study protocol. Mean antigen concentration (based on optical density) decreased more rapidly in the CP group and by month 15 was 0.11 for the IVP and 0.07 for CP groups, with equivalent median concentrations (0.04) in both groups. Conversion following heat-treatment of antigen-negative samples occurred frequently and at similar rates in both treatment groups. Based on the bias of diagnostic tests towards detection of female worms, we conclude that monthly application of 10 % imidacloprid + 2.5 % moxidectin for 9 months combined with a course of doxycycline twice daily for 28 days resulted in effective therapy against female adults in CHD. This therapeutic option may be particularly useful in cases where financial constraint or access to melarsomine precludes treatment of an infected individual. This study was supported by Bayer Animal Health.

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

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

Prevalence of canine and human dirofilariosis in Puebla, Mexico.

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

An analysis of time trends for canine heartworm disease in Grenada and its associated risk factors based on veterinary clinical pathology laboratory data base records between 2003 and 2015.

Canine heartworm (CHW) disease is a common parasitic infection in dogs in the Caribbean islands. However, studies on temporal trends and risk factors are limited for this region. This study represents the time trends in laboratory prevalence and risk factors of canine heartworm infections between 2003 and 2015. In this case series, 662 cases of laboratory-diagnosed heartworm were compared to 662 dogs without a laboratory diagnosis of heartworm (controls). One hundred and seventy two frozen serum positive samples were later analyzed for heartworm antigens using Heska solo® Step CH, and all 172 cases of microfilariae were confirmed as Dirofilaria immitis. Annual prevalence, linear trends and odds ratios (OR) for CHW were estimated using EPIINFO version 7 at a significance level of α = 0.05. Logistic regression was used to assess the association of CHW with variables showing a statistically significant univariate relationship. Laboratory prevalence of CHW decreased from 72 cases per 1000 dogs per year in 2003 to 15 cases per 1000 dogs per year in 2015 [X2 for linear trend = 151.8, p < 0.0001], with the occurrence of an epidemic of CHW between 2008 and 2010. The odds of CHW were higher among adult dogs [(OR) = 3.9 (95% CI, 2.9-7.0)] and geriatric dogs [OR = 2.1 (95% CI, 1.1-4.3)] compared to puppies. The odds of CHW were higher [OR = 1.3 (95% CI, 1.1-1.6)] among male dogs than female dogs, but the odds for CHW were lower among neutered dogs [OR = 0.4 (95% CI, 0.2 - 0.6)] compared to intact dogs. The odds of a dog being diagnosed with CHW were elevated [OR = 4.1 (95% CI, 3.2-5.2)] during the dry season compared to the rainy season. Our findings show that canine heartworm is extensive in laboratory submissions in Grenada. However, the laboratory prevalence of CHW decreased between 2003 and 2015, with an epidemic occurring between 2008 and 2010. Age of the dog, sex, neutered status, and seasonality of diagnosis were significantly associated CHW in Grenada.