Report of Dirofilaria immitis infection with acute cardiopulmonary complications in a cat from Northeastern Brazil

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.

UVEÍTE ANTERIOR COMO MANIFESTAÇÃO CLÍNICA ISOLADA DE BRUCELOSE EM CÃO

Introdução: A infecção por Brucella canis é considerada uma das etiologias da uveíte anterior em cães. Outras manifestações oculares incluem panuveíte, endoftalmite, panoftalmite, coriorretinite, vitreíte, descolamento de retina e ceratoconjuntivite. Contudo, há ainda poucos relatos na literatura que relacionam oftalmopatias à infecção natural por Brucella canis. Objetivos: Descrever a evolução clínica de um caso de uveíte anterior unilateral em cão como única manifestação de brucelose. Material e métodos: Cão, Yorkshire Terrier, 3 anos de idade, foi atendido apresentando opacidade em olho direito (OD) com evolução de duas semanas. Como histórico, paciente havia sido utilizado como reprodutor em canil e apresentava hiperlipidemia. Ao exame, verificado blefarospasmo, hiperemia conjuntival, edema de córnea e turbidez em câmara anterior em OD. A pressão intraocular foi de 11 mmHg em OD e 15 mmHg em olho esquerdo (TonoVet®). Foi iniciado tratamento em OD com prednisolona 1%, 5 vezes por dia, e hialuronato de sódio 0,15%, 3 vezes por dia, havendo melhora na primeira semana de tratamento. Porém, durante redução gradual da prednisolona até 1 vez por dia e, mesmo sob tratamento para hiperlipidemia com bezafibrato, houve recidiva do quadro. Portanto, foi mantido o tratamento com prednisolona 1%, 3 vezes por dia, sendo substituída posteriormente por diclofenaco sódico 0,1%, 1 vez por dia. Ao reduzir a frequência do diclofenaco sódico para a cada 48 horas, houve nova recidiva, quando foram solicitados hemograma, PCR para Ehrlichia canis e Babesia spp. e teste ELISA para pesquisa de anticorpos contra E. canis, Leishmania spp., Brucella canis, Anaplasma spp. e Borrelia burgdorferi e antígeno de Dirofilaria immitis. Resultados: O teste ELISA para Brucella canis foi positivo e o paciente foi submetido a tratamento com enrofloxacino e doxiciclina, ambos 10 mg/kg, 1 vez por dia, durante 30 dias. Durante o acompanhamento, não houve novas recidivas de uveíte. Conclusão: A brucelose canina é uma enfermidade que pode ser subdiagnosticada, dado que os sintomas mais frequentes, como aborto e infertilidade, são observados apenas em animais em reprodução. Assim, a pesquisa de brucelose em cães com uveíte é necessária especialmente em pacientes com histórico desconhecido ou destinados previamente a reprodução.

Review of Dirofilaria spp. infection in humans and animals in Iran

Dirofilariasis is a metazoonoses transmitted by certain mosquito genera (Culicidae: Diptera). Chiefly canids are the reservoirs of Dirofilaria spp. This article analyzed all published records and researches relevant to Dirofilaria in Iran, to provide a basis for future studies in Iran and around the world. All of the important data from human and animal cases that included the pathogen and its reservoir, dispersion, and retrospective studies were investigated and analyzed. Furthermore, the natural history of parasites, pathogenicity, diagnosis, treatment, control, and the final status of the disease in the world was briefly mentioned. Two species of the genus Dirofilaria, Dirofilaria immitis (canine heartworm) and Dirofilaria repens, are detected in Iran. Till now, 13 human cases have been formally reported including seven subcutaneous and three ocular cases of D. repens, a four cases of D. immitis, including a rare case in testicular hydrocele, one ocular and one pre-ocular, a subconjunctival and two pulmonary cases suspected to be D. immitis. Animal and human infections have been recorded in 11 provinces of Iran. Different investigators have reported D. immitis in dogs (with the frequency of 0.95–62.8%), jackals (2.5 57.4%), foxes (5.7–50%), wolves (20–50%), and cats (0.8%) and D. repens in dogs (1.4–60.8%) and jackals (10%) in different areas of the country. The reports on Dirofilaria in Iran are to some extent scattered as regarded to distribution and other features of the disease. More studies should be taken in dirofilariasis in Iran, specifically in regions from where there are no reports.

Epidemiologic, Clinical and Immunological Consequences of Co-Infections during Canine Leishmaniosis

Canine leishmaniosis (CanL) is a vector-borne, parasitic disease. CanL is endemic in the Mediterranean basin and South America but also found in Northern Africa, Asia, and the U.S. Regions with both competent sand fly vectors and L. infantum parasites are also endemic for additional infectious diseases that could cause co-infections in dogs. Growing evidence indicates that co-infections can impact immunologic responses and thus the clinical course of both CanL and the comorbid disease(s). The aim for this review is to summarize epidemiologic, clinical, and immunologic factors contributing to eight primary co-infections reported with CanL: Ehrlichia spp., Anaplasma spp., Borrelia spp., Babesia spp., Trypanosoma cruzi, Toxoplasma gondii, Dirofilaria immitis, Paracoccidioides braziliensis. Co-infection causes mechanistic differences in immunity which can alter diagnostics, therapeutic management, and prognosis of dogs with CanL. More research is needed to further explore immunomodulation during CanL co-infection(s) and their clinical impact.

Variação dos parâmetros hematológicos de cães microfilarêmicos atendidos numa clínica escola de medicina veterinária / Variation of hematological parameters of dogs microphilaremics attended in a clinic school of medicine veterinary

A dirofilariose canina, causada pelo agente etiológico Dirofilaria immitis, é uma zoonose, onde os cães são hospedeiros e reservatórios. Quando adultos, os vermes formam microfilárias por meio de reprodução sexuada e sua transmissão para o animal é feita através de mosquitos. A pesquisa de hemoparasitas é um método que possibilita identificar a presença de microfilárias no sangue. Objetivou-se estudar a variação dos parâmetros hematológicos de cães microfilarêmicos atendidos numa clínica escola de Medicina Veterinária em Marechal Deodoro/AL, entre os anos 2012 e 2019. 120 cães apresentaram microfilárias, e destes, 70 apresentaram anemia, sendo anemia normocítica normocrômica o tipo mais frequente, em 45% dos animais, seguido de anemia normocítica hipocrômica (5%), anemia macrocítica normocrômica e anemia microcítica normocrômica em 4,17%, além de policitemia (0,83%). Em relação ao leucograma, 20% dos animais apresentaram leucocitose e 10,83% leucopenia. As alterações mais frequentes foram eosinofilia (27,5%), monocitose (20%), onde 2,5% eram monócitos ativados, neutrofilia (16,67%), linfopenia (15,83%), neutropenia (10%), basofilia (4,17%) e linfocitose (2,5%), bem como desvio à esquerda moderado (6,67%) e desvio à esquerda leve (4,17%). Esses parâmetros indicam que existe um quadro inflamatório e infeccioso de caráter parasitário e crônico. Em relação à plaquetometria, 42,5% apresentaram trombocitopenia, provavelmente devido à destruição de plaquetas ocasionada pela lesão dos vasos pelas microfilárias. Os achados hematológicos podem variar devido ao tempo em que cada animal foi infectado e carga parasitária presente. Microfilárias, hemoparasitas, hematologia.

Identity of Microfilariae Circulating in Dogs from Western and South-Western Romania in the Last Decade

Dirofilaria infections in dogs are recognized as widespread mosquito-borne diseases with zoonotic potential, that are caused by the filarioid nematode (Onchocercidae) species Dirofilaria immitis and Dirofilaria repens. The long-term survey conducted in western and south-western Romania was undertaken in order to provide valuable data on the occurrence of Dirofilaria infections in dogs. Blood samples from 1088 dogs, originating from 73 localities of 11 western and south-western counties in Romania, were collected and examined using the modified Knott test. Subsequently, all of the microscopically positive samples were subjected to molecular analysis for confirmation. Altogether, the data obtained showed the percentage of dogs with circulating microfilariae to be 21.42% (233/1088) of dogs tested in the investigated region. The identified species, in cases of monoinfections, were D. immitis, D. repens, and Acanthocheilonema reconditum in 106 (9.74%) samples, 102 (9.38%) samples, and 1 (0.09%) sample, respectively. Twenty-four (2.21%) samples were simultaneously positive for D. immitis and D. repens. There was no association (p > 0.05) between infection status and breed; however, sex and lifestyle were positively associated (p < 0.05) with the percentage of dogs with circulating microfilariae and might be regarded as risk factors for infection. The results of the present investigation indicate potential zoonotic risks for humans living in the screened area and support the imperative to increase awareness among both veterinarians and physicians, regarding the continuous spread of these zoonotic filariae.

Differential diagnosis of Dirofilaria immitis nematodes (Nematoda, Onchocercidae)

Heartworm disease is a widespread anthropozoonotic disease of carnivorous animals, as well as humans. It is caused by nematodes belonging to the suborder Filariata, family Onchocercidae, genus Dirofilaria. There are about 26 species of heartworms in nature, the most common and pathogenic species in dogs and cats in most countries is Dirofilaria immitis Leidy, 1856. Mature helminths parasitize in the right ventricle and pulmonary arteries, large veins of animals and cause heart and vascular disorders, and death. Therefore, the aim of the study was to investigate the features of morphological and metric structure of adult nematodes of D. immitis isolated from the heart of dogs. Morphological studies have shown that in males the most characteristic differential features are the presence of two unequal spicules, specifically positioned relative to each other, as well as well-defined preanal and less pronounced adanal and postanal papillae. In female heartworms, the characteristic morphological features are the shape and location of the vulva. There is a difference in the structure of the esophagus in males and females. In females, the anterior and posterior parts of the esophagus are well expressed, with enlargements, in males these divisions are not pronounced. To increase the efficiency of species identification of D. immitis nematodes, it is proposed to use metric parameters that characterize the overall body size, body and width of esophagus in different areas, length of esophagus, and the location of the nerve ring. In males, 11 indicators are also suggested that characterize the size of the spicules and the location of the cloaca. In females, seven additional parameters are pointed out that characterize the location of the vulva, anus and body width in these areas. The obtained data expand the already existing data on the peculiarities of the morphological structure of parasitic nematodes of the species D. immitis and their identification.

Concern for Dirofilaria immitis and Macrocyclic Lactone Loss of Efficacy: Current Situation in the USA and Europe, and Future Scenarios

Dirofilaria immitis infection is one of the most severe parasitic diseases in dogs. Prevention is achieved by the administration of drugs containing macrocyclic lactones (MLs). These products are very safe and highly effective, targeting the third and fourth larval stages (L3, L4) of the parasite. Until 2011, claims of the ineffectiveness of MLs, reported as “loss of efficacy” (LOE), were generally attributed to owners’ non-compliance, or other reasons associated with inadequate preventative coverage. There was solid argumentation that a resistance problem is not likely to occur because of (i) the great extent of refugia, (ii) the complexity of resistance development to MLs, and (iii) the possible large number of genes involved in resistance selection. Nevertheless, today, it is unequivocally proven that ML-resistant D. immitis strains exist, at least in the Lower Mississippi region, USA. Accordingly, tools have been developed to evaluate and confirm the susceptibility status of D. immitis strains. A simple, in-clinic, microfilariae suppression test, 14-28 days after ML administration, and a “decision tree” (algorithm), including compliance and preventatives’ purchase history, and testing gaps, may be applied for assessing any resistant nature of the parasite. On the molecular level, specific SNPs may be used as markers of ML resistance, offering a basis for the validation of clinically suspected resistant strains. In Europe, no LOE/resistance claims have been reported so far, and the existing conditions (stray dogs, rich wildlife, majority of owned dogs not on preventive ML treatment) do not favor selection pressure on the parasites. Considering the genetic basis of resistance and the epizootiological characteristics of D. immitis, ML resistance neither establishes easily nor spreads quickly, a fact confirmed by the current known dispersion of the problem, which is limited. Nevertheless, ML resistance may propagate from an initial geographical point, via animal and vector mobility, to other regions, while it can also emerge as an independent evolutionary process in a new area. For these reasons, and considering the current chemoprophylaxis recommendations and increasing use of ML endectoparasiticides as a potential selection pressure, it is important to remain vigilant for the timely detection of any ML LOE/resistance, in all continents where D. immitis is enzootic.