Dirofilaria in the anterior chamber: a rare occurrence

Subconjunctival Dirofilaria masquerading as nodular scleritis

A man in his late 50s presented with a gradually enlarging, painless, reddish mass on the white portion of his left eye for 2 weeks. His best-corrected visual acuity was 20/20 in both eyes. Slit-lamp examination showed a congested, nodular, elevated lesion on the temporal bulbar conjunctiva with two pustule-like elevations. Anterior segment optical coherence tomography showed a subconjunctival solid mass rather than an abscess or a cyst. Scleral deroofing was performed and a long thread-like object resembling a dead worm was identified. The worm was removed intact, and its histopathology confirmed the diagnosis of Dirofilaria Peripheral blood smear did not show any microfilariae. No recurrences or new lesions were observed during the follow-up examinations at 1 and 5 months post-surgery. This case highlights the importance of considering a parasitic aetiology in cases of nodular or infectious scleritis.

Ocular dirofilariasis: A report from Odisha

We report a case of ocular dirofilariasis in a 68-year-old man manifesting as pre-septal abscess with gradually increasing swelling of the left eyelid and near complete ptosis of eye. A live worm was seen wriggling in the lesion while the abscess was being drained and was extracted carefully. Subsequently, it was identified as an adult female Dirofilaria repens worm. The lid edema and swelling resolved and the patient was discharged without any residual complaints.

Human subcutaneous dirofilariasis: A diagnostic dilemma

Human dirofilariasis is a rare infection caused by filarial worms of genus Dirofilaria. Humans may be infected as aberrant (accidental) hosts, mainly by Dirofilaria repens and Dirofilaria immitis. Most of the cases reported in India are of ocular dirofilariasis, with a few reports on subcutaneous dirofilariasis. We hereby report one such case of human subcutaneous dirofilariasis affecting the neck region of a 63-year male patient from Assam. This case indicates that this infection is a potentially emerging zoonosis in Assam and there is scope of finding more such cases with surveillance.

Animal and Human Dirofilariasis in India and Sri Lanka: A Systematic Review and Meta-Analysis

Dirofilariasis is an emerging vector-borne tropical disease of public health importance that mainly affects humans and dogs. Dirofilaria immitis and D. repens are the two well-documented dirofilariasis-causing filarioid helminths of both medical and veterinary concerns in India and Sri Lanka. This systematic review and meta-analysis aimed to describe and summarize the current evidence of dirofilariasis prevalence and distribution in India and Sri Lanka. Interestingly, D. repens is reported to circulate in both dogs (prevalence of 35.8% (95% CI: 11.23-60.69)) and humans (97% of published case reports) in India and Sri Lanka, but D. immitis is reported to be present in the dog populations in India (prevalence of 9.7% (95% CI: 8.5-11.0%)), and so far, it has not been reported in Sri Lanka. This peculiar distribution of D. immitis and D. repens in the two neighbouring countries could be due to the interaction between the two parasite species, which could affect the pattern of infection of the two worm species in dogs and thus influence the geographical distribution of these two filarial worms. In medical and veterinary practice, histopathology was the most commonly used diagnostic technique (31.3%; 95% CI 2.5-60.2%). The low specificity of histopathology to speciate the various Dirofilaria spp. may lead to misdiagnosis. It was identified in this study that several regions of India and Sri Lanka have not yet been surveyed for dirofilariasis. This limits our understanding of the geographical distribution and interspecies interactions of the two parasites within these countries. Parasite distribution, disease prevalence, and interspecies interactions between the vectors and the host should be targeted for future research.

Subcutaneous Dirofilariosis of the Eyelid Brought to Poland from the Endemic Territory of Ukraine

We present the case of a 60-year-old man who was diagnosed with a subcutaneous nodule on the upper eyelid of his left eye. The patient reported multiple mosquito bites during numerous work trips to Ukraine. Histopathological examination of the nodule isolated during surgery suggested Dirofilaria repens infestation. The infection was brought to Poland from the territory of Ukraine. Ophthalmologists must be aware of uncommon presentations of parasitic infestations when they consider infections of the ocular adnexa.

Human Dirofilariasis Caused by Dirofilaria repens in Sri Lanka from 1962 to 2020

PURPOSE

Sri Lanka has reported the highest prevalence of human dirofilariasis cases in Asia. Thus far, Dirofilaria repens is the only reported Dirofilaria species that affect humans, dogs, and cats in Sri Lanka. Therefore, this systematic review was carried out to analyse the studies performed on dirofilariasis in Sri Lanka.

METHODS

Peer-reviewed articles were searched on dirofilariasis published on Google Scholar, PubMed, Cochrane, and ResearchGate from January to March 2021. Articles were selected using inclusion and exclusion criteria. Three reviewers assessed the studies and extracted data independently to minimize the risk of bias. Extracted data were compiled, and then the results were compared and discussed in this systematic review.

RESULTS

Twenty-five studies performed in Sri Lanka were analysed, and high prevalence areas, frequent clinical presentations, diagnostic methods, reservoir hosts, and treatment were identified. More than 173 cases of human dirofilariasis caused by D. repens were reported from 1962 to 2020 in 20 districts among 25 investigated. The highest number of cases (n = 80) was recorded during 2010-2012 period. Canine and feline dirofilariasis are reported countrywide, and a large number of potential mosquito breeding sites could be seen in Sri Lanka.

CONCLUSIONS

The number of reported cases of human dirofilariasis has been varied from 1962 to 2020. The highest number of cases has reported in 2010-2012, and then the number of cases has dropped. This may be due to underreporting. Thus, awareness of Dirofilaria repens infection in humans, control measures in endemic areas and further research on dirofilariasis in other districts of Sri Lanka are crucial.

First time identification of subconjunctival Dirofilaria immitis in Turkey: giant episcleral granuloma mimicking scleritis

Dirofilariasis is a vector-borne disease that is present worldwide. This report describes a giant subconjunctival granuloma which mimics scleritis, caused by D. immitis. A 60-year-old man was referred with the complaints of irritation, redness, and swelling at the medial part of the right eye. He was living in Izmir province located in western Turkey. Slit-lamp examination showed a firm, immobile mass measuring 13.0 × 5.0 × 5.0 mm with yellowish creamy color. The mass was completely removed surgically under local anesthesia mainly for diagnosis. Histopathology revealed typical morphological features of a filarioid nematode in favor of Dirofilaria as characterized by the external smooth cuticular surface, cuticular layer, muscle layer, and intestinal tubule. Molecular study was performed using DNA isolated from paraffin-embedded tissue sections of the worm. PCR amplification and then DNA sequence analysis of cytochrome c oxidase subunit 1 (cox1) gene fragment confirmed that the worm was D. immitis. It is suggested that this may represent the first human case of D. immitis occurring in subconjunctival granuloma in Turkey. Although rare, D. immitis caused by ocular dirofilariasis in humans should be considered.

Ocular Dirofilariasis in Bosnia and Herzegovina: A Case Report and Review of the Literature

Purpose:

To report a rare occurrence of ocular dirofilariasis in Bosnia and Herzegovina and provide a short overview on clinical characteristics and treatment options for ocular dirofilariasis.

Methods:

A 75-year-old woman was admitted to the University Clinical Centre Tuzla with pain and redness in her left eye. A live, white, coiled, and active worm was noticed in subconjunctival space of bulbar conjunctiva.

Results:

After successful surgical extraction, the parasite was identified as the adult form of Dirofilaria repens. There were no signs of intraocular or systemic inflammation.

Conclusion:

Ophthalmologists should have in mind a possible infestation, especially in cases with repeated inflammatory reactions and swelling of the ocular region, which does not respond to conventional therapy.

Subconjunctival Dirofilariasis Presenting as Orbital Cellulitis

Human ocular Dirofilariasis is a relatively rare, zoonotic disease, caused by a filarial nematode, Dirofilaria repens. This parasitic infestation usually presents as a subconjunctival nodule with hyperemia. The authors present a case of subconjunctival dirofilariasis in a 91-year-old gentleman, who presented with manifestations of orbital cellulitis. The live worm was surgically removed and identified to be D. repens.

Recent advances on Dirofilaria repens in dogs and humans in Europe

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.

Human Subconjunctival Dirofilariasis Presenting as the Daytime Photophobia: A Case Report

We report a case of subconjunctival worm with a rare presentation of diurnal photophobia and temporal conjunctival injection. This case report describes a subconjunctival dirofilariasis in a 59-year-old man presented with foreign body sensation, localized tenderness, and eye redness during the day. After removal of subconjunctival 10 cm worm, the diagnosis was compatible with Dirofilaria immitis. Proof of identity was based on the morphological appearance, which were reliable diagnostic clues. Ocular examination was normal one month later except for faint temporal conjunctival scar. Subconjunctival dirofilariasis could present as diurnal photophobia and conjunctival injection.

An unusual presentation of lacrimal gland dirofilariasis

Dirofilariasis is a helminthic infection caused by filarial parasite of the genus Dirofilaria. It is a common zoonotic disease mostly affecting canines and uncommon in humans. It is endemic to Mediterranean countries, with few reports from other parts of the world. The clinical forms in humans are pulmonary, subcutaneous, and ocular. Ocular involvement is rare. We report a case of lacrimal gland dirofilariasis, an unusual ocular presentation which masquerades as a lacrimal gland tumor. Ours would be the third reported case in the world and first in India. This case was managed with excision of the lacrimal gland mass. Postoperatively the patient recovered completely and there has been no recurrence in the 1-year follow-up.

Ocular dirofilariasis by Dirofilaria immitis in a child in Iran: A case report and review of the literature

This report describes a rare case of ophthalmic dirofilariasis in a 2-year-old boy with redness, irritation, pain and foreign body sensation in the right eye. Slit lamp examination demonstrated a thread-like whitish nematode in the anterior chamber of the right eye that twisted around itself. The nematode worm (35mm long and 150-200μm width) was removed surgically. The presence of the smooth cuticular surface without longitudinal ridges and the vulva showed that it could be a female Diroflaria immitis. PCR amplification was done to verify the Diroflaria species. PCR amplification and sequence analysis of mitochondrial 12S rDNA confirmed that recovered worm was D. immitis. Ocular dirofilariasis caused by D. immitis is very rare, but it must be considered in humans living in endemic areas.

Human ocular dirofilariasis due to Dirofilaria repens in Sri Lanka

OBJECTIVE

To identify worms obtained from patients with eye lesions and to describe the demographic factors of patients with ocular dirofilariasis.

METHODS

A retrospective descriptive study was conducted in 31 worm samples from 30 patients referred by consultant ophthalmologists between 2006 and February 2014. Data on age, sex and site of the lesion were ascertained from the details given in the referral letters. Morphological identification of the worm was based on the maximum width, length and appearance of the cuticle. The sex of the worm was determined by the width, length and presence or absence of vulva opening. PCR was performed using Dirofilaria repens specific primers to confirm the species of worms which couldnot be identified morphologically.

RESULTS

Most of the patients belonged to the age group of 40-49 years (mean age = 42 years). Majority of them were females (70%). Subconjunctival lesions were the most frequent presentation, while the rest (n = 4) were found on eyelids. Female worms were extracted from 18 cases, and 11 had male worms. One individual had both male and female worms in a single nodule. Adults were the most commonly affected. This pattern was different from the previous studies in Sri Lanka where the most common age group affected was younger than 9 years old.

CONCLUSIONS

The present study showed a considerably high incidence of ocular dirofilariasis, stressing the importance of implementing preventive measures to reduce the transmission of this zoonotic filarial disease.

Ocular dirofilariasis: a case series of 8 patients

PURPOSE

Dirofilaria repens is an endemic parasite in Mediterranean countries that mostly affects animals. Rarely, however, it can infect humans. This case series presents patients with ocular infections due to D. repens.

MATERIALS AND METHODS

A chart review was performed of patients with ocular dirofilariasis after the year 2000, treated at a tertiary referral centre in Greece. Data were collected on the ocular, microbiological, or/and histopathological aspects and treatment.

RESULTS

Eight cases of unilateral ocular dirofilariasis were identified, of which 5 were subconjunctival (1 masquerading as nodular scleritis) and were removed through a conjunctival incision, 2 cases were intravitreal and were removed with vitrectomy, and 1 was intraorbital (adjacent to the roof of the orbit). The latter appeared as an encapsulated mass and subsequent histological examination revealed the presence of the parasite. Of the 8 cases recorded after the year 2000, 7 appeared within the last 6 years (4 cases within the last 3 years). The majority of cases involved residents of the Ionian Islands (7 of 8 cases).

CONCLUSIONS

D. repens can affect various ocular and periocular tissues. A progressive increase in the incidence of dirofilariasis was observed, which is potentially associated with climate changes in warm and moist areas where this parasite is endemic.

The burden of parasitic zoonoses in Nepal: a systematic review

Background

Parasitic zoonoses (PZs) pose a significant but often neglected threat to public health, especially in developing countries. In order to obtain a better understanding of their health impact, summary measures of population health may be calculated, such as the Disability-Adjusted Life Year (DALY). However, the data required to calculate such measures are often not readily available for these diseases, which may lead to a vicious circle of under-recognition and under-funding.

Methodology

We examined the burden of PZs in Nepal through a systematic review of online and offline data sources. PZs were classified qualitatively according to endemicity, and where possible a quantitative burden assessment was conducted in terms of the annual number of incident cases, deaths and DALYs.

Principal Findings

Between 2000 and 2012, the highest annual burden was imposed by neurocysticercosis and congenital toxoplasmosis (14,268 DALYs [95% Credibility Interval (CrI): 5450–27,694] and 9255 DALYs [95% CrI: 6135–13,292], respectively), followed by cystic echinococcosis (251 DALYs [95% CrI: 105–458]). Nepal is probably endemic for trichinellosis, toxocarosis, diphyllobothriosis, foodborne trematodosis, taeniosis, and zoonotic intestinal helminthic and protozoal infections, but insufficient data were available to quantify their health impact. Sporadic cases of alveolar echinococcosis, angiostrongylosis, capillariosis, dirofilariosis, gnathostomosis, sparganosis and cutaneous leishmaniosis may occur.

Conclusions/Significance

In settings with limited surveillance capacity, it is possible to quantify the health impact of PZs and other neglected diseases, thereby interrupting the vicious circle of neglect. In Nepal, we found that several PZs are endemic and are imposing a significant burden to public health, higher than that of malaria, and comparable to that of HIV/AIDS. However, several critical data gaps remain. Enhanced surveillance for the endemic PZs identified in this study would enable additional burden estimates, and a more complete picture of the impact of these diseases.

Various parasites that infect humans require animals in some stage of their life cycle. Infection with these so-called zoonotic parasites may vary from asymptomatic carriership to long-term morbidity and even death. Although data are still scarce, it is clear that parasitic zoonoses (PZs) present a significant burden for public health, particularly in poor and marginalized communities. So far, however, there has been relatively little attention to this group of diseases, causing various PZs to be labeled neglected tropical diseases. In this study, the authors reviewed a large variety of data sources to study the relevance and importance of PZs in Nepal. It was found that a large number of PZs are present in Nepal and are imposing an impact higher than that of malaria and comparable to that of HIV/AIDS. These results therefore suggest that PZs deserve greater attention and more intensive surveillance. Furthermore, this study has shown that even in settings with limited surveillance capacity, it is possible to quantify the impact of neglected diseases and, consequently, to break the vicious circle of neglect.

Microfilarial periodicity of Dirofilaria repens in naturally infested dogs

In the past years, canine and human cases of infestation by Dirofilaria repens (Spirurida, Onchocercidae) have been increasingly reported in several European countries. Subcutaneous dirofilariosis by D. repens may either be asymptomatic in dogs or may be characterized by subcutaneous nodules and other symptoms. Information on the periodicity of D. repens microfilariae in naturally infested animals is scant, and this might impair the accurate diagnosis of subcutaneous dirofilariosis and appropriate control plans. In the present study, eight dogs infested with D. repens were sampled twice daily at 12-h intervals for ten consecutive days, and the dog with the highest mean value of microfilariaemia was further sampled every 4 h for four consecutive days. The blood was microscopically and molecularly examined for microfilariae, and, additionally, negative samples were also subjected to a real-time PCR to evaluate the level of circulating DNA. The results demonstrated significant variations in circadian rhythms of D. repens larvae, with higher values of microfilariae per milliliter in the evening samples. A significant variation was also found at the individual level for the dogs with the highest values of microfilariaemia. All samples which were negative at the light microscopy and positive at the real-time PCR displayed levels of circulating parasite DNA <1 microfilaria per milliliter. Biological and clinical implications have been here discussed.

Human dirofilariasis: an emerging zoonosis in India

Human dirofilariasis is an uncommon zoonotic infection having a widespread geographical distribution. World over 800 cases of Dirofilaria are on record with highest numbers from Italy, Sri Lanka and republics of the ex-Soviet Union. Dirofilaria repens belongs to the subgenus Nochtiella and is the most common species identified in India. Topographically, the orbital/periorbital regions are the most common regions involved by Dirofilaria. We present a brief review of cases from India including two received in our own institute. This review focuses on the epidemiology of the disease including its geographical distribution and the probable causation of the recent increase in its incidence in Indian subcontinent.