Disease Vectors and Pathogens

Dracunculus medinensis is the scientific name for the parasite commonly known as the Guinea worm. It causes dracunculiasis.

Ans - 3

All three diseases listed - Yellow fever, Chikungunya (misspelled as Chickunhgunya), and West Nile fever - are transmitted by mosquitoes. Therefore, 'None of the above' is correct, meaning there is no disease listed that is NOT mosquito-borne.

Malaria is caused by various species of the Plasmodium parasite, including P. vivax, P. malariae, and P. falciparum, all of which are transmitted by the Anopheles mosquito.

Icterus is the medical term for jaundice, which is the yellowing of the skin and eyes caused by high levels of bilirubin in the blood. Malaria and typhoid are infectious diseases, and hemorrhage refers to bleeding.

West Nile fever is a viral disease primarily transmitted to humans through the bite of infected Culex mosquitoes. Aedes mosquitoes are typically associated with dengue and Zika viruses.

Sand flies (Phlebotomine sand flies) are the established vectors for the transmission of Leishmania parasites, which cause Leishmaniasis. Dengue is transmitted by Aedes mosquitoes, and Malaria by Anopheles mosquitoes.

When malaria schizonts rupture in RBCs, they release hemozoin - a toxic byproduct of hemoglobin digestion by the parasite. Hematin is an oxidized form of heme, hemoglobin is the blood protein, and 'heam' is misspelled.

Life cycle of Plasmodium is completed in two hosts. Man is considered to be the primary host in which schizogony occurs in liver and blood, and female Anopheles mosquito is the secondary or intermediate host in which gametogony and sporogony takes place.

Maurer's dots are observed in the erythrocytes of man infected by P. falciparum. It is characterized by the whole sole destructions of the patient's erythrocytes and the excretion of the liberated haemoglobin in the urine. This is called black water fever. 

Malaria is caused by a protozoan Plasmodium vivax. Infective stage of Plasmodium is sporozoite. Schizogony is an asexual reproduction in which schizont is formed. It undergoes Pre-erythrocytic schizogony, exoerythrocytic schizogony and erythrocytic schizogony. During erythrocytic schizogony RBCs gets ruptured to release merozoits. At this stage malaria fever is felt. 

Plasmodium vivax is a digenetic malarial parasite which completes its life cycle on two hosts-mosquito (primary host) and man (secondary host). The life cycle of Plasmodium in mosquito called sporogony and in man schizogony. Schizogony includes three stages of which pre-erythrocytic and exo-erythrocytic schizogony takes place in RBC of blood of man which characterized by the formation of signet ring stage and schizont. 

Filaiasis or elephantiasis is caused in man by a blood and lymph nematode parasite Wuchereria transmitted form man to man by female Culex.

Sleeping sickness is caused by Trypanosoma gambiense. It is a flagellate parasite of human blood transmitted by tsetse fly. In more advanced condition, the patient sleeps continuously, convulsions occur then profound coma and finally death. 

Leeches are well-known ectoparasites that feed on the blood of vertebrates. While some other organisms may be parasitic, leeches are the primary example of blood-sucking annelids.