Habitat

                      

                                    So where in the world can you find Onchocerca volvulus?

     Onchocerca volvulus’ habitat originated in West Africa in 1977 and is primarily found there because of its tropical rainforest geographical features. This is one of the two strains of this parasite. The other strain is commonly found in the savannas of Central and South America and Yemen as well.This parasite was later brought to America by African slaves. These two strains are distinguished by a DNA test called Polymerase Chain Reaction, or PCR test. Onchocerca volvulus is known to cause a disease commonly called “river blindness” because it can cause severe blindness that can affect people all throughout the world. It is also referred to as the “river blindness” because it the disease is transmitted by a black fly that tends to live near rivers.
     To survive, the black fly needs lots of oxygen from the fast water provided by the river where it usually feeds during the day (Globisch 2013). Adult females are considered to be blood feeders that often feast on birds and mammals, including humans. Because the flies bite during the day, one way to prevent getting infected by Onchocerca volvulus is by wearing long sleeved shirts and pants to avoid getting bit by the bugs while in areas they are likely to be. In heavy areas of black flies, there is a chemical that can be sprayed so that they do not bother humans as much. Adult black flies need to live by rapid water because they use the water as a device for feeding off of organic matter found in rivers (EcoSpark 2011).
     The parasite, Onchocerca volvulus is transmitted by black flies which most commonly bite into humans, and disburse larvae under the skin of a human. When the larvae is dead, it can result in skin atrophy as well as inflammation in the eyes which can lead to reduced vision and even blindness (Alberts et al. 2012). In humans, the adult parasites are often found in groups of knotted up balls in subcutaneous tissues. These groups then mature into worms and later become enclosed in fibrous tissue (Dalton 2001). These worms then feed on blood or bodily fluids from the host, whether it be a human or other animal.
     In response to the parasite, the human body reacts in different ways depending on the location of where the black fly feasts on the body. Most cases of transmission of this parasite happen in rural areas. People who are short- term visitors to places, such as Africa, are at a higher risk for getting bitten and infected by a black fly because long-term people who live there are better exposed to blackfly bites. Infections which occur in Africa often result in bumps on the skin in places such as the knees and pelvic areas, while infections that occur in Central America often result in bumps on the skin in places such as the neck and head. These bumps occur in different places because of the preference of the black flies bite which is dependent on where the black fly is from (Dalton 2012). Even though the fly will most commonly bite either of those areas, this parasite can also travel all over the human body and often enter through the eye of the human, similar to Gasterophilus intestinalis which also causes eye complications in humans.
     If a blackfly that is uninfected bites a person who has the parasite already in their body, the blackfly will then be a carrier of the parasite. It then takes the larvae of the Onchocerca volvulus to develop in the fly for it then to be infectious to humans again in the new, infected fly (Onchocerciasis FAQ 2013).
     Though the parasites' lifespan is around 10 years, and the Onchocerca volvulus can reproduce at astronomical rates. The parasite produces mass amounts of eggs and larva simply because they often do not find a host to feed off of before they die. The environment that they live in is crucial for the survival because of the hosts that are needed. The most popular regions are tropical and terrestrial because of their rivers, but are not limited to that because they can also be found in savannas, wetlands, or grasslands.

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