Evidence against Wolbachia symbiosis in Loa loa

Abstract

Background: The majority of filarial nematode species are host to Wolbachia bacterial endosymbionts, although a few including Acanthocheilonema viteae, Onchocerca flexuosa and Setaria equina have been shown to be free of infection. Comparisons of species with and without symbionts can provide important information on the role of Wolbachia symbiosis in the biology of the nematode hosts and the contribution of the bacteria to the development of disease. Previous studies by electron microscopy and PCR have failed to detect intracellular bacterial infection in Loa loa. Here we use molecular and immunohistological techniques to confirm this finding.

Absence of Wolbachia Endobacteria in Chandlerella quiscali, an Avian Filarial Parasite

“…2). Primer sets previously used to demonstrate the absence of Wolbachia in L. loa were also tested (data not shown) (McGarry et al, 2003). All primer sets employed in this study amplified Wolbachia sequences from infected species (crickets, B. malayi, W. bancrofti , and O. volvulus ) but not from Wolbachia -free filarial species ( O. flexuosa and A. viteae ) (Plenge-Bonig et al, 1995; Bandi et al, 1998) or C. quiscali .…”

“…Some of the most important filarial pathogens such as B. malayi, W. bancrofti, Dirofilaria immitis , and O. volvulus , are dependent on Wolbachia endobacteria (order Rickettsiales, family Anaplasmataceae) for growth, fertility, and sometimes even survival (Bandi et al, 1999; Hoerauf et al, 1999; Casiraghi et al, 2002; Chirgwin et al, 2003). Other filarial species are naturally Wolbachia -free and thrive in the absence of a bacterial partner (Plenge-Bonig et al, 1995; Bandi et al, 1998; Chirgwin et al, 2002; Büttner et al, 2003; McGarry et al, 2003; Ferri et al, 2011). The biological mechanisms responsible for this disparity are poorly understood.…”

Encephalitis Due to Loa loa

“…Most of these plants are well accepted and tolerated, and preliminary cytotoxicity results are encouraging (Mengome et al, 2010). There is currently no evidence of the existence of a symbiont in Loa loa (McGarry et al, 2003;Buttner et al, 2003), that might warrant concurrent antibiotic therapy for patients with loasis. Because Loa loa infection often goes undiagnosed, cases of encephalitis in Loa loa endemic areas may be attributed to viruses, bacteria or other parasites.…”

Antibiotics which Target the Wolbachia Endosymbionts of Filarial Parasites: A New Strategy for Control of Filariasis and Amelioration of Pathology

“…Furthermore, the filarial Wolbachia genome is about 85% the size of that from Wolbachia in insects [37]. The endobacteria lack the ability to make all but one amino acid, yet retain the ability to make nucleotides, heme, riboflavin and flavin adenine dinucleotide, all of which may be metabolites provided by the endobacteria to the nematode as part of the symbiosis [37].While Mansonella perstans and L. loa worms do not have Wolbachia [38][39][40], Brugia spp., M. ozzardi, O. volvulus, and W. bancrofti contain Wolbachia [41,42], thus opening up a new area for discovery of chemotherapeutic drugs against the three major causative agents of filariasis.…”