Human dirofilariosis in the 21st century: A scoping review of clinical cases reported in the literature

Abstract

Human dirofilariosis is a clinical entity caused by infection with nematode species of the genus Dirofilaria. The traditional picture depicts the disease as a sporadic event associated with the presence of a single immature worm causing a nodular lesion. With the aim to reassess this paradigm, establishing a more accurate picture of the disease and homogenize criteria, a scoping review was conducted by searching, screening and analysing published clinical cases of human dirofilariosis worldwide during the 21st century. After extracting data from 305 publications containing 576 case reports, results showed that human dirofilariosis is currently caused by five Dirofilaria species (mainly D. repens). Maturation was not uncommon, since 42.95% of the parasites recovered were described as mature worms, most of them females, 26.42% of which contained micofilariae in the uterus. Moreover, six microfilaremic cases have been described. The predominant clinical manifestation was the presence of a worm encapsulated within a nodule, but there is a considerable variety of accompanying symptoms depending on anatomical location and type of dirofilariosis. Parasites/nodules were found in 71 different anatomical locations, being the traditional nomenclature of human dirofilariosis unable to properly cover this complex situation. Delay in seeking medical assistance (patient perception) and the frequency of wrong clinical suspicions (doctor knowledge), strongly influenced clinical management. The initial suspicion in cases of subcutaneous and pulmonary dirofilariosis is predominantly a tumour, while in the ocular dirofilariosis a parasite (but not directly Dirofilaria) is mostly suspected.Surgery is usually applied, regardless of the use of non-invasive techniques during preoperative management and although its use is still limited, molecular approach is the most accurate technique to establish a species-level diagnosis. Accurate epidemiological, parasitological and clinical information while handling and reporting human clinicalThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Response to the Letter to the Editor regarding ‘Human dirofilariosis in the 21st century: A scoping review of clinical cases reported in the literature’ by Simón et al. (Transboundary and Emerging Diseases; 2021: http://doi.org/10.1111/tbed.14210)

“…cases caused by Dirofilaria repens, we agree that the results obtained in our scoping review (Simón et al, 2021) in comparison with those obtained by Pupić-Bakrač et al (2021) seem to be different. Nevertheless, it is worth mentioning that both studies are dissimilar in terms of their methodology approach.…”

Selection of new diagnostic markers for Dirofilaria repens infections with the use of phage display technology

“…Although main hosts are carnivores, especially dogs, parasites show high zoonotic potential. Human infections are described more frequently all over Europe 3 and in rare non-endemic locations like Tanzania and other African countries 4 . Human infections were initially considered incomplete in the parasite life cycle; however, several patients with active microfilaremia were reported 5 – 9 .…”

“…Human infections were initially considered incomplete in the parasite life cycle; however, several patients with active microfilaremia were reported 5 – 9 . In the twenty-first century, over 70% of described human dirofilariasis cases were caused by D. repens , and 42.95% of recovered worms were mature, mainly females, and 26.42% contained microfilariae in the uterus 3 . These reports suggest that humans should also be considered as a potential reservoir of subcutaneous dirofilariasis.…”

Selection of New Diagnostic Markers for Dirofilaria Repens Infections With the Use of Phage Display Technology

“…Although main hosts are carnivores, especially dogs, parasites show high zoonotic potential. Human infections are described more frequently all over Europe 7 and in rare non-endemic locations like Tanzania and other African countries 8 . Human infections were initially considered incomplete in the parasite life cycle; however, several patients with active micro laremia were reported [9][10][11][12][13] .…”

“…Human infections were initially considered incomplete in the parasite life cycle; however, several patients with active micro laremia were reported [9][10][11][12][13] . In the 21st century, over 70% of described human diro lariasis cases were caused by D. repens, and 42.95% of recovered worms were mature, mainly females, and 26.42% contained micro lariae in the uterus 7 . These reports suggest that humans should also be considered as a potential reservoir of subcutaneous diro lariasis.…”