Human Health and Disease Test - 28

HIV can be divided into two major types as HIV type I (HIV-I) and HIV type 2 (HIV-II). HIV-I is related to viruses found in chimpanzees and gorillas in Western Africa. HIV-I is the most common and pathogenic strain of a virus. It is further divided into three groups -  a major M group and two minor groups. The major M group is the most common type of HIV contributing to 90% of the AIDS cases. While HIV-II viruses are related to viruses found in the endangered West African primate sooty mangabey.
Thus, the correct answer is option A.

Roundworm or Ascaris is a parasitic nematode. The fertilized eggs are ovoid. The uterine wall contributes to the lumpy and thick outer layer of the egg. The mammillated layer is stained golden-brown by the bile when eggs are passed in the feces.
Therefore, the correct answer is option A.

HIV enters macrophages and CD4+ T cells and starts replicating its genetic material by using cell's machinery and thus, reducing the number os cells.
Thus, the correct answer is option A. 

Mouth cancer is the oral cancer and is any cancerous tissue growth located in the oral cavity. Chewing Betel and Areca is known to be a strong risk factor for developing oral cancer. In India, these practices are common and so, oral cancer represents upto 40% of all cancers. Mouth and throat cancer is twice as common in men as in women.
Thus, the correct answer is option (C), 'Mouth-throat cancer'.

• Culex is a genus of mosquitoes, several species of which serve as vectors of one or more important diseases of birds, humans, and other animals.
• Arbovirus infections such as West Nile virus, Japanese encephalitis, or St. Louis encephalitis, filariasis and avian malaria, Culex is a vector.
• Hence, Culex is a vector for Avian malaria, Filariasis and Japanese encephalitis disease/s.
• So, the correct answer is 'All of the above'.

Since, HIV causes AIDS. It affects the T-lymphocytes in the body and thus, cancer of lyphmatic system is more likely to occur in AIDS. 

Once male and female nematodes mate the female viviparously produces microfilariae (first stage larvae or L1) which then move through the circulatory system and collect in arterioles of the lung during the day and emerge at night (if nocturnally periodic) when night biting mosquitoes are most active. Once, the microfilariae have entered an appropriate mosquito host through its blood meal they penetrate the insect's gut wall and move to the thoracic muscles where they mature (through two life stages) into third-stage infective larvae. Following infection with third stage larvae there is usually a period of vigorous immune response to the invading larvae. If the larvae are not cleared from the body during this period then the various pathologies associated with filarial infection can develop. Most of these conditions do not appear to arise from the effects of the nematodes themselves but from immune reactions to their presence. The most pronounced of these is the damage to the lymphatic vessels which is mediated by the immune system's response to the adult worms living in them. These immune responses (Lymphangitis) are characterized by inflammation of the affected area (which are usually extremities) and fever.

Myocardial infarction (MI) occurs, when blood flow stops to part of the heart causing damage to the heart muscle. Atherosclerosis is a disease in which plaque builds up inside the arteries. Smoking is known to be a strong risk factor for premature atherosclerosis, myocardial infarction and sudden cardiac death. Smoking appears to be the cause of about 36% of deaths due to MI.
Thus, the correct answer is option (C), 'Both A and B'.

The life cycle of Wuchereria bancrofti starts when a male and a female mate inside the lymphatic vessels of an infected human. The female releases thousands of microfilariae into the bloodstream. When the host is awake, the microfilariae tend to stay in deep blood vessels. During the sleep, they travel near the surface in peripheral blood vessels. This behaviour enables them to get ingested by the night-biting mosquito. When ingested by the mosquito, the microfilariae migrate through the midgut eventually reaching the thoracic muscles. Within 1-2 weeks, they mature into first stage larvae and eventually into the third-stage infective larvae. which migrate through the haemocoel to the mosquito's proboscis. When the mosquito bites another person, the larvae are injected into the human skin. They migrate to the lymph vessels and mature into adults. So, the correct answer is option D.