Molecular characterization of 5S ribosomal spacer sequences of Dirofilaria repens microfilariae in dogs in Kerala, India.
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ABSTRACT:
SUBMITTER: Chirayath D
PROVIDER: S-EPMC7596136 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:In this study, we screened field-caught mosquitoes for presence of Dirofilaria spp. by using a polymerase chain reaction (PCR) assay. Potential occurrence of Dirofilaria repens and Dirofilaria immitis microfilariae was examined in 3,600 mosquitoes of eight species (Aedes vexans, Aedes cinereus, Aedes rossicus, Culex pipiens, Culiseta annulata, Ochlerotatus sticticus, Ochlerotatus cantans and Ochlerotatus caspius) collected from five locations in two districts (Kosice and Trebisov) of Eastern Slovakia, endemic region of canine dirofilariasis. Collection of mosquitoes was performed between May and August 2012 in premises known to be inhabited by Dirofilaria-infected dogs. PCR assays were performed on 72 pools, each pool containing 50 mosquitoes of the same species, collected on the same location. Each pool was examined separately for the presence of D. immitis and D. repens, respectively. A positive finding of D. repens was recorded in one pool of A. vexans mosquitoes collected in Košické Olšany village. Minimum infection rate in A. vexans was 1:1,750, i.e. 0.57 per 1,000 mosquitoes. The identity of D. repens was confirmed by direct sequencing of PCR product which has shown 100% homology with sequence attributed to D. repens (GenBank accession number AJ271614). This study represents the first molecular evidence of D. repens microfilariae in mosquitoes in Slovakia and highlights a need for better surveillance of zoonotic dirofilariasis in central Europe.
| S-EPMC3779099 | biostudies-literature
Project description:Human dirofilariosis is still a little known infection even in endemic areas. Dirofilariosis is zoonotic infection usually abortive in humans; instead, we report a very rare case (the 4th in the world), the first in Italy, in which at least two infective larvae became mature adults that mated and produced active microfilariae even though they did not reach peripheral blood.A 30-year-old Italian woman presented with a transient oedematous swelling on the left abdominal wall with a creeping eruption followed by the occurrence of a subcutaneous nodular painless mass in the iliac region. One month later, a similar temporary swelling appeared on the contralateral inguinal region associated with intermittent joint discomfort in both knees. The patient had recently travelled abroad, therefore many possible diagnoses were to be ruled out. Routine laboratory investigations revealed eosinophilia. An ultrasound examination of the iliac swelling evidenced a well-defined cyst with a big filamentous formation in continuous movement. A fine-needle aspiration of the lesion was performed for parasitological, cytological and histological exams. The prompt microscopic examination of the aspired material showed the presence of numerous microfilariae that were initially morphologically attributed to Mansonella ozzardi. Subsequently, the revision of the Giemsa stained film and molecular analyses of the biological material, allowed to identify Dirofilaria repens as etiological agent of infection.We report of a case in whom microfilariae were detected in fine-needle aspirate of subcutaneous node, without evidence of microfilaraemia, and the infection failed to become fully patent. Therefore we confirm that complete development and fertilization of D. repens worms in human hosts may occur, at variance with what is commonly believed, that Dirofilaria worms cannot fully develop in humans.
| S-EPMC4895828 | biostudies-other
Project description:BackgroundIn Lithuania, the first case of canine subcutaneous dirofilariosis was recorded in 2010. Since then, an increasing number of cases of canine dirofilariosis have been documented in different veterinary clinics throughout the country. Human dirofilariosis was diagnosed in Lithuania for the first time in September 2011. However, to the authors' knowledge, there are no published data on the presence and prevalence of autochthonous dirofilariosis in dogs and humans in the country. The present study provides information about the predominant species and prevalence of Dirofilaria in dogs and describes the cases of human dirofilariosis in Lithuania. It also outlines PCR detection of the bacterial endosymbiont Wolbachia that contributes to the inflammatory features of filarioid infection.ResultsA total of 2280 blood samples and six adult worms from pet and shelter dogs were collected in the central and eastern regions of Lithuania in 2013-2015. Based on their morphological appearance, morphometric measurements and molecular analysis, all the adult nematodes were identified as Dirofilaria repens. The diagnosis of microfilariae in blood samples was based on blood smear analysis and Knott's test. The PCR and sequence analysis of the ribosomal DNA ITS2 region and cox1 gene confirmed the presence of D. repens. Overall, 61 (2.7%) of the 2280 blood samples were found to be positive for the presence of D. repens. The infection rate of D. repens was significantly higher in shelter dogs (19.0%; 19/100) than in pet dogs (1.9%; 42/2180) (χ2 = 100.039, df = 1, P < 0.0001). Forty-nine DNA samples of D. repens-infected dogs were tested for the presence of the bacterial endosymbiont Wolbachia and, of these, 40 samples (81.6%) were found to be positive. Three ocular and six subcutaneous cases of human dirofilariosis were diagnosed in Lithuania in the period 2011-2018.ConclusionsTo the authors' knowledge, this is the first report of autochthonous D. repens infection in dogs and humans in Lithuania. The present data demonstrate that D. repens is the main etiological agent of dirofilariosis in Lithuania. The DNA of the filarioid endosymbiotic bacterium Wolbachia was detected in the vast majority of dogs infected with D. repens.
| S-EPMC6472076 | biostudies-literature
Project description:Dirofilaria repens is a nematode affecting domestic and wild canids, transmitted by several species of mosquitoes. It usually causes a non-pathogenic subcutaneous infection in dogs and is the principal agent of human dirofilariosis in the Old World. In the last decades, D. repens has increased in prevalence in areas where it has already been reported and its distribution range has expanded into new areas of Europe, representing a paradigmatic example of an emergent pathogen. Despite its emergence and zoonotic impact, D. repens has received less attention by scientists compared to Dirofilaria immitis. In this review we report the recent advances of D. repens infection in dogs and humans, and transmission by vectors, and discuss possible factors that influence the spread and increase of this zoonotic parasite in Europe. There is evidence that D. repens has spread faster than D. immitis from the endemic areas of southern Europe to northern Europe. Climate change affecting mosquito vectors and the facilitation of pet travel seem to have contributed to this expansion; however, in the authors' opinion, the major factor is likely the rate of undiagnosed dogs continuing to perpetuate the life-cycle of D. repens. Many infected dogs remain undetected due to the subclinical nature of the disease, the lack of rapid and reliable diagnostic tools and the poor knowledge and still low awareness of D. repens in non-endemic areas. Improved diagnostic tools are warranted to bring D. repens diagnosis to the state of D. immitis diagnosis, as well as improved screening of imported dogs and promotion of preventative measures among veterinarians and dog owners. For vector-borne diseases involving pets, veterinarians play a significant role in prevention and should be more aware of their responsibility in reducing the impact of the zoonotic agents. In addition, they should enhance multisectorial collaboration with medical entomologists and the public health experts, under the concept and the actions of One Health-One Medicine.
| S-EPMC6299983 | biostudies-literature
Project description:BackgroundHeartworms, Dirofilaria immitis, are known to be widespread in dogs and cats in the USA, but there have been no country-wide prevalence studies performed to date. There have also been no large-scale studies to determine whether the closely related species, Dirofilaria repens, occurs in the USA.MethodsTo provide this large-scale data, we examined whole blood samples (n = 2334) submitted from around the USA to the Molecular Diagnostic Laboratory at Auburn University between 2016 and 2022. Quantitative PCRs for D. immitis (targeting 16S rRNA) and D. repens (targeting cytochrome c oxidase subunit 1 gene) were performed to determine the presence of Dirofilaria DNA. DNA sequencing was performed to confirm the results.ResultsDirofilaria immitis DNA was found in 6.3% (68/1080) of the dogs from 17/39 states, and 0.3% (4/1254) of the cats from 4/42 states. None of the dogs or cats were positive for D. repens. The average 16S rRNA copy number of D. immitis in the dogs was 1,809,604 in 200 µl whole blood, while only a single copy was found in each of the four D. immitis-positive cats. The prevalence of D. immitis in dogs of different ages, sexes, and breeds did not differ significantly, but the prevalence in Southern states (7.5%, 60/803) was significantly higher than in the Western (1.7%, 1/58), Midwest (3.3%, 4/120), and Northeastern states (3.1%, 3/98) (P < 0.05). Dogs positive for D. immitis were identified in each study year (2016: 4.2%, 2/48; 2017: 9.8%, 4/41; 2018: 5.1%, 8/156; 2019: 4.9%, 15/306; 2020: 9.8%, 26/265; 2021: 4.9%, 13/264). Interestingly, dogs infected with Hepatozoon spp. (11.8%, 37/313) were significantly more likely to also be positive for D. immitis than dogs without evidence of Hepatozoon infection (3.9%, 30/760) (P < 0.0001).ConclusionsTo our knowledge, this is the first nationwide molecular survey of Dirofilaria spp. in dogs and cats in the USA, and the largest molecular survey of canine and feline dirofilariosis worldwide. Further studies are warranted to combine PCR with standard heartworm diagnostics to better understand the prevalence of Dirofilaria spp. and aid in determining the risks posed to dogs and cats in the USA.
| S-EPMC9559157 | biostudies-literature
Project description:Human subcutaneous dirofilariasis is an emerging mosquitoborne zoonosis. A traveler returning to Germany from India experienced Dirofilaria infection with concomitant microfilaremia. Molecular analysis indicated Dirofilaria repens nematodes of an Asian genotype. Microfilaremia showed no clear periodicity. Presence of Wolbachia endosymbionts enabled successful treatment with doxycycline.
| S-EPMC8153875 | biostudies-literature
Project description:This study describes two different manifestations of Dirofilaria repens infection in sibling dogs with microfilaremia. Dog 1, asymptomatic, harbored a gravid female of D. repens on the parietal layer of tunica vaginalis of one testicle and showed a marked circulating eosinophilia (3.3·103/?L). Both testicles were normal in shape and size without any gross lesions. Dog 2 had a pyotraumatic dermatitis. The cases were confirmed by PCR and sequencing. The sequences obtained showed 100% identity with those of D. repens isolated from human scrotum in Croatia. The treatment with moxidectin 2.5% and imidacloprid 10%/kg was effective in eliminating microfilariae after just one application, as demonstrated by negative modified Knott's tests and PCR analyses of blood samples. This status was maintained during the post-treatment observation period. The classical localization of D. repens in dogs is in subcutaneous tissues, within nodules or free; however, it can also occur with some frequency in testicles, as described in humans. The infection can be associated with circulating eosinophilia or pyotraumatic dermatitis, as reported in this study. Thus, in endemic areas, it is advisable to carefully inspect the removed testicles at neutering since parasite localization can take place without any macroscopic changes. Moreover, in the case of circulating eosinophilia or pyotraumatic dermatitis, investigations should include modified Knott's test and PCR to ensure that D. repens is not the cause of these alterations. Rapid and sensitive tests for the early detection of infected animals would help to prevent or limit the spread of this zoonosis.
| S-EPMC7574397 | biostudies-literature
Project description:We tried to determine the epidemiology and species of human dirofilariasis observed at two tertiary care hospitals in Kerala. We searched the hospital database to identify cases of dirofilariosis from January 2005 to March 2020. Along with human isolates, one dog Dirofilaria isolate was also subjected to PCR and sequencing of pan filarial primers cytochrome oxidase subunits 1 and 12S rDNA. We documented 78 cases of human dirofilariosis. The orbit, eyelid, and conjunctiva were the most commonly affected sites. Molecular characterization identified one dog and five human isolates as Candidatus Dirofilaria Hongkongensis. A rare case of subconjunctival infestation by B. malayi was also documented. Human dirofilariosis is a public health problem in the state of Kerala in India, and it is mostly caused by Candidatus Dirofilaria Hongkongensis. We propose that all diroifilaria isolates are subjected to sequencing for identification.
| S-EPMC8176466 | biostudies-literature
