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Review
. 2008 Apr 30;2(4):e217.
doi: 10.1371/journal.pntd.0000217.

Of mice, cattle, and humans: the immunology and treatment of river blindness

Judith E Allen  1 , Ohene Adjei, Odile Bain, Achim Hoerauf, Wolfgang H Hoffmann, Benjamin L Makepeace, Hartwig Schulz-Key, Vincent N Tanya, Alexander J Trees, Samuel Wanji, David W Taylor
Affiliations
Review

Of mice, cattle, and humans: the immunology and treatment of river blindness

Judith E Allen et al. PLoS Negl Trop Dis. .

Abstract

River blindness is a seriously debilitating disease caused by the filarial parasite Onchocerca volvulus, which infects millions in Africa as well as in South and Central America. Research has been hampered by a lack of good animal models, as the parasite can only develop fully in humans and some primates. This review highlights the development of two animal model systems that have allowed significant advances in recent years and hold promise for the future. Experimental findings with Litomosoides sigmodontis in mice and Onchocerca ochengi in cattle are placed in the context of how these models can advance our ability to control the human disease.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Life cycle of Onchocerca volvulus and Onchocerca ochengi.
Adult female worms initiate the formation of nodules in the skin (onchocercomas) (see Figures 2 and 3) in which their highly coiled bodies can reach a length of approximately 25 cm, while the males are a little over 1/10th that length. Transverse sections of adult female worms in the onchocercoma are shown in (A). Following mating, embryos develop inside the female, which gives birth to motile L1 larvae that are known as microfilaria (MF). A transverse section of an adult female with MF in utero is shown in (B); Wolbachia in lateral hypodermal chords (*) of the adult female and uterine microfilaria (arrows) are stained red. MF migrate into the dermis (shown in [C]), where they are available for transmission to the simuliid blackfly vector (shown in [D]). Within the fly, MF develop further as L1 larvae and molt into second-stage larvae, which molt again to become the infective L3 larvae (7 days). The L3 enter the skin through the wound caused by the feeding fly. The blackfly requires fast moving water to breed and thus infection occurs adjacent to rivers. Adult female worms live for several years and individuals (people or cattle) can remain microfilaraemic for their entire lives if repeatedly exposed to infection. (Photo credits: M. Boussinesq, S. Spetch, J. Allen, O Bain, S. Wanji, S. Uni)
Figure 2
Figure 2. Subcutaneous Nodules on a Child in Ghana.
Photo credit: P. Soboslay.
Figure 3
Figure 3. Intradermal Nodules Containing Adult Onchocerca ochengi on Ventral Hide of a Naturally Infected Cow (Bos indicus) in Cameroon.
Photo credit: A. J. Trees.
None
See this image and copyright information in PMC

References

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