Wolbachia: endosymbiont of onchocercid nematodes and their vectors

Abstract

Background Wolbachia is an obligate intracellular maternally transmitted, gram-negative bacterium which forms a spectrum of endosymbiotic relationships from parasitism to obligatory mutualism in a wide range of arthropods and onchocercid nematodes, respectively. In arthropods Wolbachia produces reproductive manipulations such as male killing, feminization, parthenogenesis and cytoplasmic incompatibility for its propagation and provides an additional fitness benefit for the host to protect against pathogens, whilst in onchocercid nematodes, apart from the mutual metabolic dependence, this bacterium is involved in moulting, embryogenesis, growth and survival of the host. Methods This review details the molecular data of Wolbachia and its effect on host biology, immunity, ecology and evolution, reproduction, endosymbiont-based treatment and control strategies exploited for filariasis. Relevant peer-reviewed scientic papers available in various authenticated scientific data bases were considered while writing the review. Conclusions The information presented provides an overview on Wolbachia biology and its use in the control and/or treatment of vectors, onchocercid nematodes and viral diseases of medical and veterinary importance. This offers the development of new approaches for the control of a variety of vector-borne diseases. Graphic Abstract

Bacteria Associated with the Parasitic Nematode Haemonchus contortus and Its Control Using Antibiotics

“…The gut bacteria may be essential to the host by providing nutrients such as haem, vitamins and cholesterol. The bacteria in the reproductive tract may be endosymbionts that manipulate the reproduction of the nematode [32]. Future studies using next-generation sequencing instead of clone libraries may provide deeper and comprehensive insight into the resident bacteria populations.…”

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

“…Future research should determine whether the absence of male worms in these cases is due to their non‐localisation, to the possibility that the development of male worms is more difficult than of female worms in the human host or to other factors such as those related to reproductive mechanisms that do not require the participation of male worms, for example, parthenogenesis, which is used by other parasitic nematodes such as those in the genus Strongyloides (Streit, 2017). In addition, these reproductive mechanisms and other types of alterations are caused in a large number of arthropod species containing Wolbachia bacteria, which have evolved a mutualistic interaction with Dirofilaria spp., among other filarial species (Manoj et al., 2021).…”

Zoonotic Dirofilaria immitis and Dirofilaria repens infection in humans and an integrative approach to the diagnosis

“…Under the above circumstances, the endosymbiont Wolbachia screening may also serve as an alternative/additional method for the diagnosis of dirofilariasis. Filarioids use Wolbachia for embryogenesis, development, fertility and longevity of the adult worm (Bandi et al, 1998;Simón et al, 2012;Lustigman et al, 2014;Manoj et al, 2021). This endosymbiont is released into the circulation and stimulate the host immune system, producing inflammation and immune response (Simón et al, 2012;Lustigman et al, 2014).…”

“…Under the above circumstances, the detection of Wolbachia has been suggested as a further test to refine the diagnosis of human dirofilarioses. These obligatory endosymbionts of filarioids play a major role in the pathogenesis of both acute and chronic filariasis; therefore, they have been targeted for the treatment and indirect diagnosis of these parasitosis (Turba et al, 2012;Manoj et al, 2021). Hence, the current study adopted an integrated approach including serology, molecular detection of filarioids and their endosymbionts Wolbachia.…”