Biology · General Awareness

Disease Vectors and Pathogens

820 Questions

Disease vectors and pathogens examine how organisms like Plasmodium and Leishmania transmit infections. Test items require matching vectors to specific diseases. Studying these life cycles is essential for scoring well.

Plasmodium infective stagesDisease transmission modesDisease vectors and fleasIntracellular parasitesElephantiasis causes

Disease Vectors and Pathogens Questions

Multiple choice

Which of the following statements is incorrect regarding filariasis?

  1. Lymphatic filariasis is caused by Wuchereria bancrofti.

  2. Subcutaneous filarias is caused by Loa.

  3. Filariasis is usually diagnosed by finger prick test.

  4. Elephantiasis results when the parasites lodge in the nervous system of an organism.

  5. Serous cavity filariasis is caused by Mansonella perstans and Mansonella ozzardi.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Elephantiasis results when the parasites lodge in the lymphatic system.

Multiple choice

Which of the following statements does not characterise onchocerciasis?

  1. The parasite worm is spread by the bite of a black fly.

  2. A vaccine against this disease does not exist.

  3. Onchocerciasis is also known as river blindness.

  4. Adult worms remain in subcutaneous nodules, limiting access to the host's immune system.

  5. The microfilaria migrate to the skin during the night.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The microfilaria migrate to the skin during the day.

Multiple choice

Type 1 T helper (Th1) cells produce interferon-gamma, interleukin (IL)-2, and tumour necrosis factor (TNF)-beta, which activate macrophages at the time of infections. Th1 cells are of major importance in defence against which of the following protozoans?

  1. Trypanosoma brucei

  2. Leishmania donovani

  3. Malarial merozoites

  4. Malarial sporozoites

  5. Trichinella spiralis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Th1 cells produce cytokines which activate the killing macrophages. Where Th2 cells predominate, antibodies are produced and the individual responds poorly to the infection.

Multiple choice

Which of the following statements regarding the life cycle of malarial parasite is incorrect?

  1. The sporozoites travel to the liver and invade liver cells.

  2. Over 5-16 days, the sporozoites grow, divide and produce tens of thousands of merozoites.

  3. The merozoites exit the liver cells and re-enter the bloodstream.

  4. Some of the merozoite-infected blood cells leave the cycle of sexual multiplication.

  5. When a mosquito bites an infected human, it ingests the gametocytes.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Some of the merozoite-infected blood cells leave the cycle of asexual multiplication. Instead of replicating, the merozoites in these cells develop into sexual forms of the parasite, called male and female gametocytes that circulate in the bloodstream.

Multiple choice

An increased total IgE level indicates that it is likely that a person has one or more allergies. High IgE levels are found in infections with which of the following protozoans?

  1. Trypanosoma cruzi

  2. Trypanosoma rhodesiense

  3. Plasmodium falciparum

  4. Trichinella spiralis

  5. Leishmania tropica
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Parasites like Trichinella frequently increase the IgE levels, usually polyclonally. This tends to inhibit the protective effect of IgE by diluting out the specific IgE on the mast cell. Inflammation induced by mast cell degranulation leads to influx of IgG which causes damage to the parasite.

Multiple choice

The main nourishment for the male mosquito is

Directions: Read the given passage carefully and answer the given question.

We learn throughout that tigers and sharks are dangerous animals. We are also scared of them because they are big and powerful. However, as we get older we learn that sometimes the most dangerous animals are also the tiniest animals. In fact, the mosquito is the animal that kills many people every year and is probably the most dangerous. It may seem that all mosquitoes are biters, but this is not actually the case. Male mosquitoes eat plant nectar. On the other hand, female mosquitoes feed on animal blood. They need this blood to live and produce eggs. When a female mosquito bites a human being, it transmits a small amount of saliva into the blood. This saliva may or may not contain a deadly disease. The result of the bite can be as minor as an itchy bump or as serious as death by a disease like malaria and yellow fever. Although mosquitoes may not seem as scary as larger, more powerful animals, they are far more dangerous to human beings.

  1. blood

  2. nectar

  3. larva

  4. saliva
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

“Male mosquitoes eat plant nectar” suggests the answer.

Multiple choice

The deadliest animal that we face in our daily life is the

Directions: Read the given passage carefully and answer the given question.

We learn throughout that tigers and sharks are dangerous animals. We are also scared of them because they are big and powerful. However, as we get older we learn that sometimes the most dangerous animals are also the tiniest animals. In fact, the mosquito is the animal that kills many people every year and is probably the most dangerous. It may seem that all mosquitoes are biters, but this is not actually the case. Male mosquitoes eat plant nectar. On the other hand, female mosquitoes feed on animal blood. They need this blood to live and produce eggs. When a female mosquito bites a human being, it transmits a small amount of saliva into the blood. This saliva may or may not contain a deadly disease. The result of the bite can be as minor as an itchy bump or as serious as death by a disease like malaria and yellow fever. Although mosquitoes may not seem as scary as larger, more powerful animals, they are far more dangerous to human beings.

  1. white ant

  2. ladybug

  3. female mosquito

  4. male mosquito
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It is given, "the mosquito is the animal that kills the most people every year and is probably the most dangerous." As “Male mosquitoes eat plant nectar”, they are not dangerous. 

Multiple choice

Match the following:

 
Group - I (Human diseases) Group - II (Causative protozoans)
P. African sleeping sickness 1. Toxoplasma gondii
Q. Chaga’s disease 2. Trypanosoma brucei
R. Toxoplasmosis 3. Plasmodium falciparum
S. Malaria 4. Trypanosoma cruzi
5. Balantidium coli

  1. P - 2, Q - 4, R - 1, S - 3

  2. P - 2, Q - 1, R - 4, S - 3

  3. P - 2, Q - 4, R - 3, S - 1

  4. P - 1, Q - 3, R - 4, S - 2

  5. P - 4, Q - 3, R - 1, S - 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The correct set of codes is P - 2, Q - 4, R - 1, S - 3.

Multiple choice

Which one of the following is a protozoan disease?

  1. Typhoid

  2. Malaria

  3. Night blindness

  4. Ringworm
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Malaria is caused by protozoan parasites of the Plasmodium genus, transmitted by Anopheles mosquitoes. Typhoid is bacterial, Night blindness is from vitamin A deficiency, and Ringworm is a fungal infection - none are protozoan.

Multiple choice

Plasmodium which causes malaria is reproduced by _____________.

  1. binary fission

  2. multiple fission

  3. regeneration

  4. spore formation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plasmodium reproduces asexually through multiple fission (schizogony), where one cell divides into many daughter cells simultaneously. This occurs in human liver and red blood cells during the malaria lifecycle.