How Disease is Spread by Vectors
In medical science or biology, a vector refers to an agent (microbes, animals or person) that does not cause disease by itself but helps in transmitting the pathogens that cause disease from one host to another. In this sense, the host could be humans, animals or plants. These vectors have contributed to the epidemic of so many diseases. Different diseases are transmitted by different vectors but some ailments share common vectors. For instance female anopheles mosquitoes are responsible in transmitting malaria and yellow fever in humans (Mueller et al, 2007), while ‘plague’ is transmitted by fleas. As for plant diseases, many of them are transmitted by aphids. These vectors have different modes of spreading diseases as mosquitoes shall been taken as a case study on how they aid the spread of malaria. Malaria is a disease characterized by general body aches, shivering and sweating. It is caused by a parasite called plasmodium which has several species that affects humans. For this parasite to spread, it needs its host, humans and mosquitoes, the vector. A part of plasmodium life cycle takes place in human and the other part in mosquitoes. Female anopheles mosquitoes are the parasite’s preferred vector that spreads malaria. When female anopheles mosquitoes, which prefer to feed in the night, bite an infected human, the parasites in ingested by the mosquito and in the process becomes infected with plasmodium sporozoites which are carried in the salivary glands of the mosquito. After the mosquito is infected, the gametocytes present in the human blood as at the time of biting and which have found its way into the mosquito’s intestine dissociates into male and female gametes. These gametes later join together inside the mosquito’s guts (Talman et al, 2004). The fusion of these gametes give rise to ookinete and these penetrate through the infected mosquito’s gut to further produce oocyst. Within the oocyst are several...
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