Blood-feeding in the young adult filarial worms litomosoides sigmodontis

In this study with the filarial model Litomosoides sigmodontis, we demonstrate that the worms ingest host red blood cells at a precise moment of their life-cycle, immediately after the fourth moult. The red blood cells (RBC) were identified microscopically in live worms immobilized in PBS at 4 degrees C, and their density assessed. Two hosts were used: Mongolian gerbils, where microfilaraemia is high, and susceptible BALB/c mice with lower microfilaraemia. Gerbils were studied at 12 time-points, between day 9 post-inoculation (the worms were young 4th stage larvae) and day 330 p.i. (worms were old adults). Only the very young adult filarial worms had red blood cells in their gut. Haematophagy was observed between days 25 and 56 p.i. and peaked between day 28 and day 30 p.i. in female worms. In males, haematophagy was less frequent and intense. Similar kinetics of haematophagy were found in BALB/c mice, but frequency and intensity tended to be lower. Haematophagy seems useful to optimize adult maturation. These observations suggest that haematophagy is an important step in the life-cycle of L. sigmodontis. This hitherto undescribed phenomenon might be characteristic of other filarial species including human parasites

Zoonotic onchocerciasis caused by a parasite from wild boar in Oita, Japan

Histological examination of a nodule removed from the back of the hand of a 58-year-old woman from Oita, Kyushu, Japan showed an Onchocerca female sectioned through the posterior region of the worm (ovaries identifiable) and young (thin cuticle). Six Onchocerca species are enzootic in that area: O. gutturosa and O. lienalis in cattle, O. suzukii in serows (Capricornis crispus), O. skrjabini and an Onchocerca sp. in Cervus nippon nippon, and O. dewittei japonica in wild boar (Sus scrofa leucomystax). Diagnostic charactets of female Onchocerca species, such as the cuticle and its ridges, change along the body length. Tables of the histologic morphology of the mid- and posterior body-regions of the local species are presented. In addition, it was observed that transverse ridges arose and thickened during the adult stage (examination of fourth stage and juvenile females of O. volvulus). The specimen described in this report, with its prominent and widely spaced ridges, was identified as O. d. japonica. Four of the 10 zoonotic cases of onchocerciasis reported worldwide were from Oita, three of them being caused by O. d. japonica, the prevalence of which in local wild boar was 22 of 24 (92 %)

Zoonotic onchocerciasis caused by a parasite from wild boar in Oita, Japan

Histological examination of a nodule removed from the back of the hand of a 58-year-old woman from Oita, Kyushu, Japan showed an Onchocerca female sectioned through the posterior region of the worm (ovaries identifiable) and young (thin cuticle). Six Onchocerca species are enzootic in that area: O. gutturosa and O. lienalis in cattle, O. suzukii in serows (Capricornis crispus), O. skrjabini and an Onchocerca sp. in Cervus nippon nippon, and O. dewittei japonica in wild boar (Sus scrofa leucomystax). Diagnostic charactets of female Onchocerca species, such as the cuticle and its ridges, change along the body length. Tables of the histologic morphology of the mid- and posterior body-regions of the local species are presented. In addition, it was observed that transverse ridges arose and thickened during the adult stage (examination of fourth stage and juvenile females of O. volvulus). The specimen described in this report, with its prominent and widely spaced ridges, was identified as O. d. japonica. Four of the 10 zoonotic cases of onchocerciasis reported worldwide were from Oita, three of them being caused by O. d. japonica, the prevalence of which in local wild boar was 22 of 24 (92 %)