Filarial worms: a systematic review and meta-analysis of diversity in animals from Iran with emphasis on human cases.

Current systematic review and meta-analysis demonstrate the prevalence reports of filariasis in animals in Iran along with human cases. Studies were screened, relevant papers were selected and the random-effect model was used by forest plot with 95% confidence interval (CI). Of 17 records of human case-reports, particularly from Khuzestan province (5 cases), Dirofilaria repens was the most detected parasite (10 cases) with higher involvement of the right eye (7 cases) than other organs. Eleven animal species were reported to be parasitised by filarioids in Iran. The prevalence of Dirofilaria immitis in canids was 14.69% (95% CI: 10.33-19.67), with highest rates (20.92%; 95% CI: 13.84-29.03) in free-ranging dogs. Male (10.07%; 95% CI: 5.10-16.47) and more than 1-year old (20.77%; 95% CI: 8.66-36.42) dogs were more likely to be found infected. The frequency of other filarioids of zoonotic interest was: Acanthocheilonema reconditum in dogs 2.15% (95% CI: 0.71-4.33), Dipetalonema evansi in camels 10.16% (95% CI: 4.73-17.34), Onchocerca cervicalis in horses 3.63% (95% CI: 1.44-6.75%) and Onchocerca fasciata 16.57% (95% CI: 10.12-24.24%) in camels. Still, our knowledge on parasitic filariae in Iran is limited and more investigation is needed in both human and animal populations.

Phylogenetic characterization of Setaria equina and its association with other filarids.

Molecular characterization studies on Setaria equina are limited. The present study aimed to characterize S. equina at the cytochrome c oxidase gene and to examine its phylogenetic relationships with other filarid species. Sequence analysis showed 100% nucleotide homology with an S. equina sequence from Italy (AJ544873). However, both sequences exhibited 7 nucleotide substitutions from a S. equina donkey isolate from Egypt (MK541847). Overall, S. equina formed a monophyletic sister group to Setaria tundra. All Setaria spp. examined formed a separate group on the phylogenetic tree that was related to corresponding Onchocerca spp. and Dirofilaria spp. clades. Human filarid worms-Brugia spp. and Wuchereria spp. grouped in a separate clade alongside Theilezia spp. Dipetalonema spp.-formed a separate group at the top of the tree.

Cercopithifilaria species in dogs and ticks from Greece.

Filarioids of the genus Cercopithifilaria (Spirurida, Onchocercidae) are parasites of wild and domestic animals in tropical and subtropical regions being transmitted by ixodid ticks. Though this filarioid species have been studied in canine and tick populations in Europe, data on their species diversity and geographical distribution in Greece is scant. Thus, the aims of this study were to investigate the presence of Cercopithifilaria spp. in dogs and ticks across Greece and to assess the possible risk factors. A total of 500 skin biopsies were collected from dogs, while 508 ticks were collected from 180 infested animals and examined. Sediments from skin biopsies were microscopically screened for detection of dermal microfilaria (mfs). Skin samples (n = 115) and tick specimens (n = 153) were molecularly subjected by PCR. Overall, 70 samples (14%) scored positive for mfs. Specifically, 68 samples (13.6%) were positive for Cercopithifilaria bainae and two (0.4%) were co-infected with C. bainae and Cercopithifilaria sp. II. Molecular analyses revealed that all sequences obtained belong to C. bainae. Haplotype I was the most frequent (92.6%), followed by haplotype XVIII (3%) and haplotypes II and IX (1.5%). Three new haplotypes of C. bainae, named XIX, XX, and XXI, were also identified. Among the risk factors examined, habitat, dog use, body weight, tick infestation history, and the use of acaricides were associated with the presence of C. bainae. The estimated prevalence of Cercopithifilaria spp. demonstrates that these filarioids are common in dogs and ticks in Greece. Finally, the identification of 7 haplotypes for C. bainae confirms their genetic variability.

First report of the isolation and phylogenetic characterization of equine Setaria digitata from India based on mitochondrial COI, 12S rDNA, and nuclear ITS2 sequence data.

Equine ocular setariasis arising mainly from ectopic infestation of Setaria digitata is a common vision impairing ophthalmic disease in India, and the identification of this filarial nematode is based solely on morphology. However, morphological characters alone are inadequate to detect and differentiate S. digitata from its congeners. The present communication reports the first phylogenetic characterization of equine S. digitata from India based on sequences derived from the mitochondrial cytochrome c oxidase subunit 1 (COI), the mitochondrial small subunit ribosomal DNA (12S rDNA), and the nuclear internal transcribed spacer 2 (ITS2). Three isolates were characterized for each gene, and respective sequences were submitted to NCBI database (MN078131, MN078132, and MN095798). The sequences were also compared with the other related sequences available from PubMed around the globe, and phylogenetic analysis was carried out in conjunction with nucleotide homologies. There was no intraspecific variation among the Indian isolates. The phylogenetic analysis of S. digitata, inferred from these genes, showed that the isolate sequences obtained from different host species created a separate monophyletic clade within the genus Setaria with minor sequence variations revealing similar molecular characteristics of S. digitata isolates throughout the globe. In addition, the studied Indian isolates were found closer to Sri Lankan isolates. The S. digitata and S. labiatopapillosa appeared as sister species.

New host and geographical records for Parafilaroides normani (Nematoda: Filaroididae) Dailey, 2009 in South American fur seal, Arctocephalus australis, from southern Brazil.

Lungworms are a common finding in seals and fur seals around the world. However, from existing records, the biogeographical distribution of filaroid helminths appears to be restricted, and these parasites are endemic in only certain areas and species, mainly in the Northern Hemisphere. The occurrence of infection in pinniped species in the Southern Hemisphere is scarce. The objective of this work is to verify the prevalence of lungworms in Arctocephalus australis in waters off the southern coast of Brazil. Twenty subadult specimens of A. australis found recently dead on the southern coast of Brazil were necropsied and their lungs were examined. Parasitic cysts were found in only one specimen (prevalence of 5%). The helminths were morphologically identified as Parafilaroides normani (Metastrongyloidea: Filaroididae). This helminth species has been reported in pinnipeds from Australia, New Zealand and South Africa. This is the first record of P. normani in A. australis and for the western South Atlantic, providing additional data regarding the biogeographic distribution of the parasite.

Molecular detection of vector-borne pathogens from mosquitoes collected in two zoological gardens in Germany.

In Germany, knowledge of disease agents transmitted by arthropods in zoological gardens is scarce. In the framework of ecological studies, mosquitoes were therefore collected in German zoological gardens and examined for mosquito-borne pathogen DNA and RNA. In total, 3840 mosquitoes were screened for filarial nematodes and three groups of viruses (orthobunyaviruses, flaviviruses, alphaviruses) while 405 mosquitoes were tested for avian malaria parasites. In addition to the filarial nematode species Dirofilaria repens (n = 1) and Setaria tundra (n = 8), Sindbis virus (n = 1) and the haemosporidian genera Haemoproteus (n = 8), Leucocytozoon (n = 10) and Plasmodium (n = 1) were demonstrated. Identified pathogens have the potential to cause disease in zoo and wild animals, but some of them also in humans. Positive mosquitoes were collected most often in July, indicating the highest infection risk during this month. Most of the pathogens were found in mosquito specimens of the Culex pipiens complex, suggesting that its members possibly act as the most important vectors in the surveyed zoos, although the mere demonstration of pathogen DNA/RNA in a homogenised complete mosquito is not finally indicative for a vector role. Outcomes of the study are not only significant for arthropod management in zoological gardens, but also for the general understanding of the occurrence and spread of mosquito-borne disease agents.

New insights into the clinico-histopathological and molecular features of Pelecitus (Filarioidea: Onchocercidae) from a raptor bird.

Some Onchocercidae nematodes such as Pelecitus are parasites of medical and veterinary importance. The adult stage of Pelecitus has been reported infecting birds, and the microfilaria has been associated to human blindness. However, in some of these cases, the nematode was incompletely identified at the species level due to the scarcity of morphological taxonomic keys and, also, to the lack of molecular diagnostic analysis. Here, we report a new Pelecitus species in a crested caracara (Caracara cheriway) producing a severe tenosynovitis and microfilarial dermatitis. It is also the first record of Pelecitus in an American bird of prey. Clinical and histopathological features are described, contributing towards our understanding of the pathogenesis of Pelecitus and the health and conservation of wild bird populations. Our study also provides new information on the molecular diagnosis of this parasite and highlights the potential role of wild birds as Pelecitus reservoirs, and health risk for humans and wildlife.

Detection of Cercopithifilaria bainae in western Romania.

Cercopithifilaria species are tick-transmitted filarial parasites of mammals. In Europe, three Cercopithifilaria spp. are known to parasitize dogs, all occurring mainly in the Mediterranean countries. In Romania, Cercopithifilaria bainae has been reported in a single dog in eastern Romania but the occurrence in other parts of the country is not known. To further elucidate the geographic distribution of Cercopithifilaria spp. infection, 544 ticks were collected from dogs in several locations across Romania. The presence of Cercopithifilaria spp. was investigated with real-time PCR. A single Dermacentor reticulatus female tick was found to be infected with Cercopithifilaria bainae. The finding in the present study is geographically separated from the previous finding in Romania by 800 km, as well as by the Carpathian mountain range. Hence, C. bainae is more geographically widespread in Romania than previously recognized. However, the single detection does suggest that infection is rather uncommon in Romanian dogs. Nevertheless, further studies on Cercopithifilaria spp. distribution and prevalence are needed.

GRANULOMATOUS FILARIAL ENCEPHALOMYELITIS CAUSED BY CHANDLERELLA QUISCALI IN A NORTHERN CRESTED CARACARA (CARACARA CHERIWAY).

A northern crested caracara (Caracara cheriway) was presented after being found nonambulatory in a field. On physical examination, the bird had severe hind-limb paresis. The bird did not improve after 10 days of hospitalization and was euthanized. Histologic examination of the cerebrum and spinal cord revealed multiple adult filarial nematodes surrounded by granulomatous inflammation with several multinucleated giant cells. These parasites were confirmed to be Chandlerella quiscali with polymerase chain reaction. This is the first report of C. quiscali in a bird of prey.

Endothelial cells release soluble factors that support the long-term survival of filarial worms in vitro.

The inability to maintain filarial nematodes in long-term in vitro culture greatly limits research into the basic biology of these parasites and hinders in vitro screening of novel anti-filarial agents. In this study, we sought to characterize nutrients that promote the long-term survival of filarial worms in vitro. Using microfilariae (MF) obtained from gerbils infected with Litomosoides sigmodontis, a filarial parasite of rodents, we found that Dulbecco's Modified Eagle Medium (DMEM) supplemented with 10% fetal bovine serum (FBS) resulted in MF survival of only 5 days. However, co-culturing MF with a mouse endothelial cell line (EOMA) enabled survival for 40 days. Culturing EOMA cells in transwell plates extended MF survival to the same degree as direct co-culture, suggesting that the factors microfilariae require are soluble in nature. Heat inactivation of EOMA conditioned media at 56 °C reduced MF survival by approximately 50%, and heat inactivation at 100 °C reduced survival to 3 days, demonstrating that both heat labile and heat stable factors are involved. EOMA cells require FBS to produce these factors, as conditioned media collected from EOMA cells grown in the absence of FBS failed to prolong survival. The removal of lipids also abrogated survival, indicating MF are likely utilizing lipid factors released by EOMA cells. Dialysis experiments demonstrate that at least some of the required factors are between 0.1 and 1 kDa in size. Importantly, L. sigmodontis adult worms also show significantly extended survival when cultured in EOMA conditioned media. Together, these results suggest that EOMA-produced factors include lipid-containing molecules, heat labile molecules (likely a protein), and micronutrients between 0.1 and 1 kDa in size. These studies have established a cell-free approach to maintaining MF and adult stage filarial worms in long-term in vitro culture and have taken important steps towards biochemically characterizing host-derived nutrients required for parasite survival.

First report of Filaria martis Gmelin, 1790 in the European mink, Mustela lutreola (Linnaeus, 1761).

The riparian European mink (Mustela lutreola), currently surviving in only three unconnected sites in Europe, is now listed as a critically endangered species according to the IUCN. Habitat loss and degradation, anthropic mortality, interaction with the feral American mink (Neovison vison), and infectious diseases are among the principal causes of its decline. Surveys of helminth parasites of this host that also include focus on subcutaneous potentially pathogenic helminths such as those belonging to the genus Filaria are very scarce. We report here the presence of specimens of Filaria martis in the subcutaneous connective tissues of three M. lutreola individuals from Spain. This is the first finding of a subcutaneous nematode in a representative of the genus Mustela. The report also enlarges the known range of the definitive hosts of this nematode. These worms were mainly located in the dorsal region of mink and more rarely in the knees, elbows, and hips. Skin sloughing was only observed in one M. lutreola with both septicaemia and an associated high burden of F. martis. Therefore, more attention should be paid to potentially pathogenic helminths when designing conservation programs dedicated to M. lutreola.

Canine filarial infections in Liguria, north-west Italy.

This paper reports the findings of a study on the presence of various species of filarial nematodes in dogs in Liguria, north-west Italy, a region traditionally considered free from the disease. Between 2009 and 2012 blood samples were taken from 365 dogs in rural areas in Liguria. The blood samples were then submitted to Knott's test, histochemical staining, polymerase chain reaction (PCR) and the enzyme-linked immunosorbent assay (ELISA) for Dirofilaria immitis antigens. Overall, 35 of the 365 dogs were positive using Knott's test for microfilariae (prevalence 9.6%; 95% confidence interval (CI): 6.6-12.6%). Acanthocheilonema reconditum was the most prevalent species (8.0%), while Dirofilaria repens (1.4%) and Dirofilaria immitis (0.6%) were less common. One co-infection by D. repens and A. reconditum was observed. All morphological identifications were confirmed by histochemical staining and PCR. In addition, a retrospective analysis of data on D. immitis antigens in 11,363 samples of canine sera was carried out. Sera were collected and analysed for D. immitis antigens by the Istituto Zooprofilattico Sperimentale (IZS) of Piedmont, Liguria and Aosta Valley (Imperia section) between 2004 and 2013 during annual tests for leishmaniasis on autochthonous dogs throughout Liguria. Serological data from IZS showed an overall seroprevalence of 0.65% (95% CI: 0.50-0.80%) for D. immitis throughout the region. The present study updates the epidemiological map of canine filarial infections in Italy and suggests the need for surveillance and prophylaxis in Liguria.

Molecular and phylogenetic analysis of the filarial nematode Micipsella numidica from the hare Lepus europaeus in Italy.

The genus Micipsella comprises three species of filariae to date identified in lagomorphs only, whereas the other genera belonging to the subfamily Splendidofilariinae are described as parasites of birds, reptiles and mammals. In the present study seven specimens of Micipsella numidica (Seurat, 1917), collected from the hare Lepus europaeus in Italy, were characterized genetically by molecular amplification of the mitochondrial genes (12S rDNA; cox1) and the 5S rDNA gene spacer region. Phylogenetic trees inferred using available sequences from filariae and those identified in this study evidenced a close relationship between M. numidica and Splendidofilariinae of other mammals and reptiles (Rumenfilaria andersoni and Madathamugadia hiepei). The present findings, apart from adding new data about the hosts in Italy, support the taxonomic position of M. numidica and highlight the substantial biological and molecular differences existing between Splendidofilariinae and other Onchocercidae. The study also contributes to our knowledge of the molecular/genetic diagnosis of filarial parasites of veterinary and medical concern in any vertebrate or invertebrate host.

Litomosoides sigmodontis: a jird urine metabolome study.

The neglected tropical disease onchocerciasis affects more than 35 million people worldwide with over 95% in Africa. Disease infection initiates from the filarial parasitic nematode Onchocerca volvulus, which is transmitted by the blackfly vector Simulium sp. carrying infectious L3 larvae. New treatments and diagnostics are required to eradicate this parasitic disease. Herein, we describe that a previously discovered biomarker for onchocerciasis, N-acetyltyramine-O-glucuronide (NATOG) is also present in urine samples of jirds infected with the onchocerciasis model nematode Litomosoides sigmodontis. Increased NATOG values paralleled a progressing infection and demonstrated that quantification of NATOG in this rodent model can be utilized to track its infectivity. Moreover, our findings suggest how NATOG monitoring may be used for evaluating potential drug candidates.

Identification of Avian and Hemoparasite DNA in Blood-Engorged Abdomens of Culex pipiens (Diptera; Culicidae) from a West Nile Virus Epidemic region in Suburban Chicago, Illinois.

Multiple mosquito-borne parasites cocirculate in nature and potentially interact. To understand the community of parasites cocirculating with West Nile virus (WNV), we screened the bloodmeal content of Culex pipiens L. mosquitoes for three common types of hemoparasites. Blood-fed Cx. pipiens were collected from a WNV-epidemic area in suburban Chicago, IL, from May to September 2005 through 2010. DNA was extracted from dissected abdomens and subject to PCR and direct sequencing to identify the vertebrate host. RNA was extracted from the head or thorax and screened for WNV using quantitative reverse transcriptase PCR. Seventy-nine engorged females with avian host origin were screened using PCR and amplicon sequencing for filarioid nematodes, Haemosporida, and trypanosomatids. Filarioid nematodes were identified in 3.8% of the blooded abdomens, Plasmodium sp. in 8.9%, Haemoproteus in 31.6%, and Trypanosoma sp. in 6.3%. The sequences from these hemoparasite lineages were highly similar to sequences from birds in prior studies in suburban Chicago. Overall, 50.6% of blood-fed Culex pipiens contained hemoparasite DNA in their abdomen, presumably from current or prior bloodmeals. Additionally, we detected hemoparasite DNA in the blooded abdomen of three of 10 Cx. pipiens infected with WNV.

Cercopithifilaria spp. in dogs in Sardinia Island (Italy).

A survey on Cercopithifilaria spp. was carried out on owned and kennelled dogs in Sardinia, Italy. A total of 180 dogs were sampled and tested by microscopic detection or PCR of dermal microfilariae in skin snip sediments. The overall prevalence for Cercopithifilaria spp. at both microscopy and molecular tests was 9.4 % (17/180), while 8.3 % (15/180) of dogs scored positive at microscopic detection of sediments only. Of the 225 microfilariae measured, 212 were identified as Cercopithifilaria bainae and the remaining as Cercopithifilaria sp. II. All samples were molecularly processed for specific amplification of cytochrome oxidase subunit 1 (cox1) and ribosomal 12S gene fragments. The Basic Local Alignment Search Tool analysis of the cox1 and 12S sequences here obtained showed a high nucleotide similarity (99 and 100 %, respectively) with those of C. bainae available in GenBank. In particular, cox1 haplotype I (HI; n=14), haplotype HXVIII (n=2), and a new haplotype, named HXIX (n=1), differing for a single polymorphism from HI, were detected. This study reports data on the occurrence, distribution, and genetic makeup of C. bainae and Cercopithifilaria sp. II infesting dogs in Sardinia, suggesting that these filarioids are spread in areas where Rhipicephalus sanguineus sensu lato ticks occur.

Geographic Distribution and Neuropathology of Elaeophora schneideri in Shiras Moose (Alces alces shirasi) in Idaho, USA.

Elaeophorosis, infection by the filarial worm Elaeophora schneideri, is a parasitic disease of wild ungulates in North America; however, our understanding of the relevance of E. schneideri to moose (Alces alces) morbidity and mortality is incomplete. Between March 2020 and July 2022, necropsy and histopathology were performed on 61 Shiras moose (Alces alces shirasi) in Idaho, US. Among the 41 adults (greater than 1 yr old), 21 moose were from northern Idaho, and 20 were from southeastern Idaho. Elaeophorosis was diagnosed in 24% (10 of 41). All 10 infected moose were from southeastern Idaho; none of the 21 moose from northern Idaho were infected. No juvenile moose (nine from northern and 11 from southeastern Idaho) were infected. Microfilariae were detected histologically in 9 of 10 infected moose, most consistently in brain tissue associated with lesions indicative of ischemic injury to the neuroparenchyma attributed to occlusion of arterioles and capillaries by microfilariae or fibrin thrombi, including edema, necrosis, and glial nodules. Microfilariae found in other tissues of the head, including the eye, tongue, and pinnae of some animals, as well as in lung, heart, liver, and kidney, typically were associated with inflammation. Three of the 10 infected moose had cropped ears attributed to elaeophorosis, and four exhibited abnormal behavior, which may have been due to neuropathology associated with E. schneideri microfilariae in the brain.

Integrated Histological and Molecular Analysis of Filarial Species and Associated Wolbachia Endosymbionts in Human Filariasis Cases Presenting Atypically in Thailand.

Atypical presentations of filariasis have posed diagnostic challenges due to the complexity of identifying the causative species and the difficulties in both diagnosis and treatment. In this study, we present the integrative histological and molecular analysis of seven atypical filariasis cases observed in regions of nonendemicity of Thailand. All filariasis cases were initially diagnosed based on histological findings. To confirm the causative species, molecular characterization based on both filarial mitochondrial (mt 12S rRNA and COI genes) and nuclear ITS1 markers was performed, together with the identification of associated Wolbachia bacterial endosymbionts. Among the cases studied, Brugia pahangi (N = 3), Brugia malayi (N = 1), Dirofilaria sp. "hongkongensis" (N = 2), and a suspected novel filarial species genetically related to Pelecitus copsychi (N = 1) were identified. By targeting the 16S rRNA gene, Wolbachia was also molecularly amplified in two cases of infection with Dirofilaria sp. "hongkongensis." Phylogenetic analysis further revealed that the detected Wolbachia could be classified into supergroups C and F, indicating the high genetic diversity of this endosymbiont in Dirofilaria sp. "hongkongensis." Furthermore, this study demonstrates the consistency between histological findings and species identification based on mitochondrial loci rather than on the nuclear ITS1. This suggests the utility of mitochondrial markers, particularly COI, as a highly sensitive and reliable diagnostic tool for the detection and differentiation of filarial species in clinical specimens. Precise identification of the causative species will facilitate accurate diagnosis and treatment and is also essential for the development of epidemiological and preventive strategies for filariasis.

Detection and characterization of vector-borne parasites and Wolbachia endosymbionts in greater one-horned rhinoceros (Rhinoceros unicornis) in Nepal.

Vector-borne parasite infections affect both domestic and wild animals. They are often asymptomatic but can result in fatal outcomes under natural and human-induced stressors. Given the limited availability of molecular data on vector-borne parasites in Rhinoceros unicornis (greater one-horned rhinoceros), this study employed molecular tools to detect and characterize the vector-borne parasites in rescued rhinoceros in Chitwan National Park, Nepal. Whole blood samples were collected from thirty-six R. unicornis during rescue and treatment operations. Piroplasmida infections were first screened using nested polymerase chain reaction (PCR) targeting 18S ribosomal RNA gene. Wolbachia was detected by amplifying 16S rRNA gene, while filarial nematodes were detected through amplification of 28S rRNA, COI, myoHC and hsp70 genes. Our results confirmed the presence of Theileria bicornis with a prevalence of 75% (27/36) having two previously unreported haplotypes (H8 and H9). Wolbachia endosymbionts were detected in 25% (9/36) of tested samples and belonged to either supergroup C or F. Filarial nematodes of the genera Mansonella and Onchocerca were also detected. There were no significant association between T. bicornis infections and the age, sex, or location from which the animals were rescued. The high prevalence of Theileria with novel haplotypes along with filarial parasites has important ecological and conservational implications and highlights the need to implement parasite surveillance programs for wildlife in Nepal. Further studies monitoring vector-borne pathogens and interspecies transmission among wild animals, livestock and human are required.

Filarial Nematodes in Dogs from the Northeast Region of Brazil.

PURPOSE: Medical and veterinary filarial nematodes are transmitted by blood-feeding vectors. In dogs, these parasites are mainly represented by nematodes in which microfilariae dwell in the blood (Dirofilaria spp. and Acanthocheilonema spp.) or skin (Cercopithifilaria spp. and Onchocerca lupi). The aim of this study was to determine the prevalence of these filarial infections in dogs residing in a touristic, heavily populated location in the northeastern region of Brazil. METHODS: Blood samples (n = 245) were assessed by a modified Knott test, followed by a qualitative ELISA test (SNAP® 4Dx® Plus, IDEXX Laboratory, Westbrook, Maine, USA) for the detection of antibodies against Anaplasma spp., Borrelia burgdorferi sensu lato, Ehrlichia spp. and antigens of Dirofilaria immitis. Skin samples (n = 71) were microscopically examined and molecularly assessed through a PCR targeting the 12 S rRNA gene. RESULTS: Microfilariae and antigen of D. immitis were detected simultaneously in 15 (6.1%; 95% CI = 3.7-9.8) animals. Nine animals (3.6%; 95% CI = 1.9-6.8) were D. immitis antigen positive but microfilariae negative and nine other animals (3.6%; 95% CI = 1.9-6.8) were microfilariae positive but D. immitis antigen negative. D. immitis positive dogs were found in four different municipalities. No filarioids were detected in the skin after microscopical and molecular analyses. CONCLUSION: Data from this study demonstrate that D. immitis is the main filarial nematode infecting dogs in coastal areas in northeastern Brazil. Based on the potential risk of infection in which animals are submitted, it is essential to perform tests to detect microfilariae and D. immitis antigen. Preventive measures must be adopted by using microfilaricidal compounds and anti-feeding insecticides to prevent canine infection.