Disease Causative Agents

Lead poisoning can lead to fatal diseases one including anaemia. Lead inhibits certain enzymes required for the synthesis of heme molecule. Heme is an integral part of haemoglobin of the RBCs. It carries oxygen in the body and provides to the cells for aerobic respiration. Lead poisoning indirectly leads to the loss of oxygen-carrying capacity of the RBCs and in turn can be fatal. So, the correct answer is option D.

The Blackfoot disease affects the peripheral vascular system. It is endemic in nature. It is associated with the consumption of inorganic arsenic from the artesian wells. Arsenicosis is caused by exposure over a period of time to arsenic in drinking water. Arsenic contamination in water may also be due to industrial processes, such as those involved in mining, metal refining, and timber treatment. WHO's guideline value for arsenic in drinking water is 0.01 mg /litre.

AIDS (Acquired immunodeficiency syndrome) is an infection which is caused by Human immunodeficiency virus (HIV). The causative agent of the disease is a virus and so the disease can spread from one person to the other by sexual contact. The disease alsoe spreads through the use of teh infected needles, syringes and blood transfusion from the infected person.

AIDS is an infectious disease that spreads through sexual contact. It also spreads through blood transfusion, use of common needles and syringes or from infected mother to her baby during pregnancy or breast feeding.

AIDS and hepatitis-B are sexually transmitted diseases that are spread by contact with infected body fluids which include blood, semen, vaginal fluid or other body fluids through the mucous. Thus the correct answer is option A.

AIDS (Acquired immunodeficiency syndrome) is an infection which is caused by Human immunodeficiency virus (HIV). The causative agent of the disease is a virus and so the disease can spread from one person to the other by sexual contact. The disease also spreads through the use of the infected needles, syringes and blood transfusion from the infected person.

STD are sexually transmitted diseases that are transmitted through sexual contact. Treponema pallidum is a bacterium that causes syphilis disease. Human immunodeficiency virus (HIV) causes AIDS. Neisseria gonorrhoeae is a bacterium that causes Gonorrhea disease. Hepatitis B virus causes hepatitis disease. Out of these diseases, Syphilis is very difficult to diagnose. Hence, this makes it the most dangerous STD.

The sexually transmitted diseases also called venereal diseases, are spread by sexual intercourse with an infected person. The major venereal diseases are syphilis and gonorrhea. Gonorrhoea is caused by a diplococcus bacterium, Neisseria gonorrhoeae. The victim feels burning sensation and pain during urination. Thus option A is the correct answer.

Trichomoniasis is a sexually transmitted disease. It is caused by Trichomonas vaginalis.
Malaria is caused by Plasmodium sp and pneumonia by Diplococcus pneumonia. 

Syphilis is a type of sexually transmitted disease , which is caused by a bacteria . It starts as painless sores . It is caused by the bacteria Treponema pallidum . So the correct option is 'syphilis' . 

Syphilis is caused by bacterium Treponema pallidum. It is a sexually transmitted disease (STD) which is transmitted through sexual intercourse with infected person. Haemophilia is an X-linked genetic disorder of blood, It is not transmitted via any sexual practice. Genital herpes is an STD while sickle-cell anaemia is an autosomal hereditary disorder. The chances of a 5 years old boy contacting an STD are very rare since he is unlikely to have sex at this age. So, the correct answer is 'The chances of a 5-years boy contracting a STD are very rare'.

Zika virus is a flavivirus, similar to Dengue, Yellow fever, and Japanese encephalitis, and is transmitted by the same Aedes mosquito vectors.

Subcutaneous anthrax occurs when the bacteria enter through a cut or abrasion on the skin, which is classified as direct contact.

Category C agents include emerging pathogens that could be engineered for mass dissemination, and Hantavirus is classified as such.

Hepatitis C is primarily transmitted through direct contact with infected blood, such as through shared needles or medical procedures.