New paradigms in research on Dirofilaria immitis

Abstract

Background Since the advent of ivermectin (along with melarsomine and doxycycline), heartworm has come to be viewed as a solved problem in veterinary medicine, diminishing investment into non-clinical research on Dirofilaria immitis. However, heartworm infections continue to pose problems for practitioners and their patients and seem to be increasing in frequency and geographic distribution. Resistance to preventative therapies (macrocyclic lactones) complicates the picture. The use of chemotherapy for other kinds of pathogens has benefitted enormously from research into the basic biology of the pathogen and on the host-pathogen interface. A lack of basic information on heartworms as parasites and how they interact with permissive and non-permissive hosts greatly limits the ability to discover new ways to prevent and treat heartworm disease. Recent advances in technical platforms will help overcome the intrinsic barriers that hamper research on D. immitis, most notably, the need for experimentally infected dogs to maintain the life cycle and provide material for experiments. Impressive achievements in the development of laboratory animal models for D. immitis will enhance efforts to discover new drugs for prevention or treatment, to characterize new diagnostic biomarkers and to identify key parasite-derived molecules that are essential for survival in permissive hosts, providing a rational basis for vaccine discovery. A ‘genomics toolbox’ for D. immitis could enable unprecedented insight into the negotiations between host and parasite that enable survival in a permissive host. The more we know about the pathogen and how it manipulates its host, the better able we will be to protect companion animals far into the future. Graphical Abstract

Human Subcutaneous Dirofilariasis Behind a Blepharoconjunctivitis: A Case Report and Review of the Literature

“…In the case of D. tenuis , the primary host is mainly the raccoon. Human subcutaneous or pulmonary dirofilariasis can be caused by any of the aforementioned parasites [ 3 , 4 , 10 ].…”

First case of macrocyclic lactone-resistant Dirofilaria immitis in Europe - Cause for concern

“…Heartworm disease is one of the most important parasitic diseases in dogs worldwide. It can be potentially lethal for animals, it has zoonotic implications, and its prevalence and geographic distribution are likely spreading around the world due to climate change ( Simón et al, 2012 ; Fuehrer et al, 2021 ; Geary, 2023 ).…”

Cercopithifilaria spp. of dogs: little known but prevalent filarioids beneath the skin

“…Canine filarioids are a group of vector-borne nematodes infecting dogs and other animal species worldwide, with the filarial worm Dirofilaria immitis being considered one of the most important mosquito-borne parasites due to the cardiopulmonary disease it may cause [ 1 , 2 ]. Conversely, Dirofilaria repens , which localizes in subcutaneous tissues, causes a less relevant clinical form in dogs but is the major cause of zoonotic infection in humans [ 3 ].…”