Lastly, let's go to Onchocerciasis. Onchocerciasis, also known as river blindness, is a parasitic disease caused by Onchocerca Volvulus, and is transmitted by blackflies. This is second in the world only to Trachoma as infectious cause of blindness, and that's why it's called the river blindness. Onchocerciasis is mostly found in the sub-Sahara African. Some cases also in South Arabian peninsula, and isolated of Central and South America. An estimated 18 million people suffer from this disease, with approximately 270,000 cases of blindness related to this infection. Let's look at the morphology of the parasite more or less similar to lymphatic species. The sexes are coiled to form bundles, but instead of habiting the lymphatics, they form in subcutaneous connective tissue or encased in fibrous capsules or nodules. Microfilariae is sheathless, unlike the one, unlike Wuchereria Bancrofti, which has got a sheath. This one is found in the fluid of nodules, cavity, and surrounding skin. Highest concentrations are in skin, areas of skin favorable to local vectors. For example, in Africa region, the most common areas are the hips, while the South American form is in the head area. The epidemiology of this determinants of transmission intensity vectors, parasite, host, and the environmental climate conditions. The deficiency is important as this is determined by the vector capacity. This takes into account the abundance, the survival rate, survival to the parasite can now, support the development of the parasite, which takes about twelve days, as well as the feeding habits. As you have seen, there are specific species which are responsible for transmissions of the Onchocerciasis, which causes blindness and the specific species of the Onchocerciasis, strains which cause skin manifestation. So the parasite strains are just as important as a we've seen in cases of malaraia. Host behavior is important, so is the social and economic conditions. Economic conditions that have the ability to control, ability to access interventions. Demography is important, because where you have good environmental condition, the transmission intensity is quite high. Environmental conditions and climate conditions. These are the words which determine the densities of the vectors. Prevention and control. Just like in the photoflourescense, the mass chemotherapy is important and with the control method described and blackflies. I'll play equal here. Thank you. This one shows a picture with Africa where you can see a small girl leading an adult. And another, two small children leading a chain of young people who could have contributed in the field by working, but not because of this blindness. Then the whole population is affected, the young and the old.