Q10. Which among foot-and-mouth disease, anthrax, black quarter and cowpox are infectious diseases of livestock?
[UPSC CSE Prelims 2005]
(A) First three only
(B) Last three only
(C) First and fourth only
(D) All four
Answer: (D) All four
Explanation: All listed diseases are infectious, although their agents differ. Foot-and-mouth disease and cowpox are viral, whereas anthrax and black quarter are bacterial. Recognising that animal viral disease is part of general biology broadens coverage beyond human infections.
Q9. Which influenza A subtype is popularly associated with avian influenza?
[UPPSC Special Mains 2004]
(A) H5N1
(B) H1N1 exclusively
(C) Zika
(D) HIV-1
Answer: (A) H5N1
Explanation: H5N1 is a subtype of influenza A linked to bird flu outbreaks in poultry and wild birds. The letters specify haemagglutinin and neuraminidase. Surveillance matters because avian influenza viruses sometimes infect mammals, including humans, after relevant exposure.
Q8. Which HIV-1 subtype has historically been predominant in India?
[UPPSC Special Mains 2004]
(A) Subtype A
(B) Subtype B
(C) Subtype C
(D) Subtype D
Answer: (C) Subtype C
Explanation: HIV-1 subtype C has historically accounted for most HIV infections in India. HIV also exhibits substantial genetic diversity, which matters to epidemiology and vaccine research. The subtype classification describes viral genetic lineages, not separate nonviral diseases.
Q7. Which set could all represent manifestations of advanced HIV/AIDS:
enlarged lymph nodes,
night sweats,
memory problems and
weight loss?
[UPSC CSE Prelims 2003]
(A) First two only
(B) Last three only
(C) First, second and third only
(D) All four
Answer: (D) All four
Explanation: Advanced HIV disease can produce persistent lymph-node enlargement, constitutional symptoms, weight loss and neurological impairment. These findings are nonspecific individually, so laboratory testing is needed for diagnosis. Effective treatment can reduce opportunistic illness and improve survival.
Q6. What is a common route by which poliovirus enters the human body?
[Uttarakhand PSC Prelims 2003]
(A) Dog bites
(B) Mosquito bites
(C) Food or water contaminated with faeces
(D) Contact with pollen
Answer: (C) Food or water contaminated with faeces
Explanation: Poliovirus commonly spreads through the faecal–oral route, particularly where sanitation is inadequate. Most infections cause no paralysis, but a small fraction invade the nervous system. Vaccination and improved hygiene are core prevention measures.
Q5. Which disease cannot be cured by routine antibacterial antibiotics?
[RPSC RAS Prelims 2003]
(A) Leprosy
(B) Tetanus
(C) Measles
(D) Cholera
Answer: (C) Measles
Explanation: Measles is caused by a highly contagious virus, so antibiotics do not treat the primary infection. Leprosy, tetanus and cholera have bacterial causes, although their management differs. Vaccination is the key preventive measure against measles.
Q4. Foot-and-mouth disease affecting cloven-hoofed livestock is caused by what?
[UPSC CSE Prelims 2002]
(A) Bacterium
(B) Fungus
(C) Protozoan
(D) Virus
Answer: (D) Virus
Explanation: Foot-and-mouth disease is caused by an aphthovirus of the family Picornaviridae. It spreads rapidly among susceptible cloven-hoofed livestock, including cattle, pigs and sheep. The animal disease should not be confused with human hand, foot and mouth disease.
Q3. Which collection contains only viral diseases?
[Uttarakhand PSC Mains 2002]
(A) Tuberculosis, herpes and rabies
(B) Mumps, rabies and herpes
(C) Cancer, tuberculosis and polio
(D) Chickenpox, cancer and tuberculosis
Answer: (B) Mumps, rabies and herpes
Explanation: Mumps, rabies and herpes are all caused by viruses, although they differ greatly in transmission and affected organs. Tuberculosis is bacterial, and cancer is a broad disease category with many causes. Poliomyelitis and chickenpox are also viral.
Q2. Why does AIDS cause profound immunodeficiency?
[Uttarakhand PSC Mains 2002]
(A) HIV primarily blocks red-cell oxygen carriage
(B) HIV impairs T-helper lymphocytes
(C) HIV converts platelets into fungi
(D) HIV increases skin pigmentation
Answer: (B) HIV impairs T-helper lymphocytes
Explanation: HIV infects and damages CD4-positive T-helper lymphocytes, which coordinate immune responses. Progressive immune injury raises susceptibility to opportunistic infections and certain cancers. CD4 monitoring and antiretroviral viral-load suppression are key concepts in HIV care.
Q1. Ranikhet disease, also known as Newcastle disease, principally affects which animals?
[Uttarakhand PSC Prelims 2002]
(A) Poultry such as chickens
(B) Cattle
(C) Goats only
(D) Horses
Answer: (A) Poultry such as chickens
Explanation: Newcastle disease is an infectious viral disease of birds, especially poultry, caused by avian orthoavulavirus 1. It can spread quickly through flocks and may produce respiratory or neurological signs. Vaccination and poultry biosecurity help control outbreaks.
