No evidence of Wolbachia endosymbiosis with Loa loa and Mansonella perstans

Abstract

Endosymbiotic Wolbachia bacteria from different filarial species, including major pathogens of humans such as Wuchereria bancrofti, Brugia malayi and Onchocerca volvulus, seem to play an important role in the development, viability and fertility of these worms. Wolbachia trigger inflammatory host responses as well as adverse reactions against standard treatment regimens and are therefore under investigation as novel treatment targets. We investigated whether Wolbachia are also endosymbiotic in Loa loa and Mansonella perstans. In both male and female adult L. loa, we found no evidence of bacteria by light or transmission electron microscopy. Furthermore, Wolbachia-specific PCR was negative in both L. loa and M. perstans microfilariae. The absence of Wolbachia in both filarial species therefore discourages the use of antibiotics as an adjunct or alternative approach to current treatment concepts for both loiasis and mansonelliasis perstans.

Mapping the presence of Wolbachia pipientis on the phylogeny of filarial nematodes: evidence for symbiont loss during evolution

“…The absence of W. pipientis in L. loa reported in our work has also been recorded in other recent studies (Brouqui et al, 2001;Büttner et al, 2003 andGrobusch et al, 2003) and agrees with the results of previous investigations on the ultrastructure of this species (e.g. Franz et al, 1984).…”

“…Recent studies have provided evidence for the absence of W. pipientis in Loa loa and Setaria equina (Chirgwin et al, 2002;Büttner et al, 2003 andGrobusch et al, 2003). Furthermore, microfilariae of Mansonella perstans have been shown to be negative for W. pipientis through PCR (Grobusch et al, 2003). In addition to the data generated through PCR and sequencing, electron microscopy and immunohistochemical examinations have contributed to the above picture of the presence/absence of W. pipientis in filarial species (e.g.…”

“…see Bandi et al, 1998 andHoerauf et al, 1999; for tables listing filarial species positive and negative for W. pipientis, see Bandi et al, 2001). Recent studies have provided evidence for the absence of W. pipientis in Loa loa and Setaria equina (Chirgwin et al, 2002;Büttner et al, 2003 andGrobusch et al, 2003). Furthermore, microfilariae of Mansonella perstans have been shown to be negative for W. pipientis through PCR (Grobusch et al, 2003).…”

The Nematoda Filarioidea: critical analysis linking molecular and traditional approaches

“…1). Wolbachia was not detected in M. (E.) perstans (Grobusch et al, 2003) but was detected in the other three species; it belongs to the supergroup F of the endosymbiont (work in progress).…”

Wolbachia endosymbionts and human disease control

“…However, antibiotic experimentation suggests that despite loss of Wolbachia, the worms can survive for long periods of time [84]. Secondly, as mentioned previously, several filarial nematodes do not have or require Wolbachia for fertility or survival [37,[85][86][87][88]. Where Wolbachia are not present, there is the presence of laterally transferred Wolbachia DNA (LGTs), suggesting that in their evolutionary past Wolbachia was present in these species [83,85,[89][90][91][92].…”