Blindness

Introduction:

This paper will discuss the microorganisms involved in causing river blindness, Onchocerca volvulus and Wolbachia ssp. Relationship, how has the understanding between Onchocerca volvulus and Wolbachia changed river blindness is treated, what effects this treatment has on Onchocerca volvus and Wolbachia, the experimentalprocedure and the results that determined the cause of inflammatory symptoms of river blindness.

The microorganisms involved in causing river blindness?

River blindness is a devastating tropical disease that has blamed a parasitic nematode that has blinded at least 250,000 people now living in Africa and South America. The disease is caused by parasitic worms that burrow into the skin and release millions of tiny offspring that spread throughout the body. (Stolk 2067)It is the bacteria inside the parasitic worms, and not the worms themselves, cause river blindness. The repeated bites from the black flies that are common along rivers and streams in tropical areas have also transmitted the disease to people living in that area. (Saint Andre 1892 )”According to Jan Bradley a parasitologist at the University of Nottingham, United Kingdom in the article Focus page 1809 a victim of the disease can have hundreds of worms wiggling in the eye.” River blindness is also the second-leading infectious cause of blindness in the world today.

Onchocerca volvulus and Wolbachia spp. and their relationship to each other?

Unfortunately, Onchocerca volvulus doesn't travel alone at all stages of their life cycle,the worms contain Wolbachia spp. that appear to be an essential relationship to each other. The worms contain Wolbachia bacteria that appear to be essential companions. The worms also need Wolbachia spp. to reproduce successfully. With the close relationship between the worm and bacteria in mind researchers have developed experiments to uncover Wolbachia exact role in the development of river blindness. (Stolk 2067)

“According to The Science article vol 295 edition March 8, 2002, researchers use mouse model for the disease, they infected nine mice with extracts taken from worms treated with doxycycline which contain relatively few Wolbachia and with extracts from nontreated worms with a normal Wolbachia load. Mice exposed to the treated extracts showed significantly less thickening and haze of the eye's cornea and less signs of the inflammation such as infiltration of white cells into the cornea, compared to mice that were infected with the untreated extracts. Previous studies have also showed an important role for T cells, parasite specific antibodies, and information of immune complexes in O.volvulus keratitis. This is to determine whether TLR4 regulates keratitis in the presence of an adaptive immune response. (Pennisi 1809)

A body's innate immune response plays a large part in how the disease progresses. Mice lacking a key immune cell receptor molecule called TLR4 showed fewer signs of the eye inflammation when exposed to Wolbachia laden worm extract. These mice produced smaller amounts of other immune molecules and proteins that are normally recruited to fight the infection. This is suggesting that TLR4 might regulate Wolbachia-triggered inflammation by controlling the expression of these immune molecules. (Taylor 727)

How has understanding the symbiosis between Onchocerca volvulus and Wolbachia changed ...