Tag: some common diseases

• Filariasis is a parasitic disease caused by an infection with roundworms such as Wuchereria bancrofti.
  
• Amoebiasis, also known as amoebic dysentery, is an infection caused by Entamoeba. The housefly transmits pathogens via touch or from bodily fluids, including from their saliva, faeces, vomit, and urine. Housefly act as a vector for amoebic dysentery, typhoid, cholera, Trachoma, tapeworm, roundworm, leprosy, mycoses etc.
  
• Malaria is a mosquito-borne infectious disease that affects humans and other animals. The vector for malaria is female Anopheles mosquito.
  
• Ascariasis is a disease caused by the parasitic roundworm Ascaris lumbricoides. The source of infection is from objects which have been contaminated with faecal matter containing eggs.
  

Female Anopheles mosquito is a vector for Malarial parasite. Infection occurs when the mosquito bites an infected person and then later on bites a healthy person, while it feeds on the blood of the host.

Normal RBCs are disc-shaped and can move easily through the blood vessels. RBCs contain haemoglobin, which carries oxygen from lungs to rest of the body. Sickle cells contain abnormal haemoglobin called sickle haemoglobin or haemoglobin S. This causes the RBCs to develop sickle or crescent shape. These cells are stiff and sticky and tend to block the blood flow in the blood vessels, which can cause pain and organ damage and also increased the risk for infection. So, the correct answer is option C.

Phlebotomus is a genus of sand flies. They are primarily responsible for the transmission of leishmaniasis, an important parasitic disease. The most common forms are cutaneous leishmaniasis which causes skin sores and visceral leishmaniasis which affects several internal organs.
Therefore, the correct answer is option A.

Kala azar is also known as 'black fever' and is considered to be the most severe form of leishmaniasis. It is caused by the protozoans of Leishmania genus. 

The occurrence of more than one form of an individual  in a single species within an interbreeding population is known as polymorphism. Trypanosoma shows this feature with three main forms, all of which have a small kinetoplast and a conspicuous undulating membrane. Hence, option B is correct.

Human African trypanosomiasis, also known as sleeping sickness, is a vector-borne parasitic disease. It is caused by infection with protozoan parasites belonging to the genus Trypanosoma. They are transmitted to humans by tsetse fly (Glossina genus) bites which have acquired their infection from human beings or from animals harbouring the human pathogenic parasites.