What areas do I avoid?

One of the first records of an infection of the Loa loa involved in 1707 features a young girl in Santo Domingo, Dominican Republic suffering from “severe stabbing eye pain.” A surgeon subsequently extracted a worm from her eye (Padgett and Jacobsen 2008). Today, Loa loa  infects millions of people from West and Central Africa (Padgett and Jacobsen 2008). An estimated 30 million people live at risk of contracting this parasite (Antinori et al. 2012).  Cases occur most often in rainforests of Cameroon, with a 54% endemic, as well as the Republic of the Congo, the Democratic Republic of Congo, the Central African Republic, Gabon, Equatorial Guinea, and Nigeria (Padgett and Jacobsen 2008). However, cases in Western countries are becoming more common because of travelers and immigrants who visit the endemic areas (Padgett and Jacobsen 2008, Antinori et al. 2012).

Inhabiting human inhabitants

While the Loa loa primarily inhabits African countries, they dwell within two different hosts during their life cycle. So, as far as their habitat goes it spends the larva stage within flies of the genus Chrysops. These bloodsucking flies transfer these larva to a human host so that they can mature in the subcutaneous tissue, or under the skin (Padgett and Jacobsen 2008). Finally, Loa loa returns to the fly when it sucks the blood of an infected human host and ingests the young parasitic nematode and the cycle starts over (Padgett and Jacobsen 2008).  Learn more about this cycle on the REPRODUCTION page. These parasites can live detectably under the sclera of the eye as well as the bridge of the nose, the penis, testes, nipples, kidneys, or heart (Padgett and Jacobsen 2008). They tend to invade the blood during the day for a chance to transfer their eggs through the blood when the fly has a blood meal from infected human host (Padgett and Jacobsen 2008). At night, they dwell in the vascular section of the lungs (Padgett and Jacobsen 2008). They depend on the fluids from the tissues of humans and use secreted digestive enzymes to obtain these nutrients (Harris 2003). The likelihood of contracting this parasite increases when you are within wet areas, like the rainforest or swamps, during the rainy season because these conditions are more favorable for the fly population, the transmitters to humans (Padgett and Jacobsen 2008). So, Loa loa thrives all over Africa as well as some western countries due to immigration and travelers, but only within two different organisms at certain points of their life cycle (Padgett and Jacobsen 2008).

Learn about Loa loa MORPHOLOGY.
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