Why Do We Fall Ill? - Practice Test, Class 9 Science - Class 9 MCQ

Elephantiasis disease, also known as lymphatic filariasis, is a parasitic infection caused by microscopic worms. It is primarily transmitted through mosquito bites and affects the lymphatic system, leading to swelling and enlargement of body parts, typically the legs and genitals. The disease can have long-term effects on our health. Here are the details:
1. Definition of Elephantiasis:
- Elephantiasis is a chronic and debilitating disease caused by the filarial worm, which invades the lymphatic system.
2. Transmission and Risk Factors:
- Elephantiasis is transmitted through the bite of infected mosquitoes.
- Living in areas with poor sanitation and where the disease is endemic increases the risk of infection.
3. Symptoms:
- The initial symptoms may include fever, chills, headache, and swelling of the lymph nodes.
- Over time, the affected body parts, usually the legs, arms, breasts, or genitals, become enlarged and swollen.
- The skin may become thickened, rough, and discolored.
4. Long-term Effects on Health:
- Elephantiasis can cause significant physical and psychological distress.
- The swelling and enlargement of body parts can lead to mobility issues, difficulty in performing daily activities, and social stigma.
- Chronic inflammation and recurrent infections can occur in the affected areas, further compromising health.
- In severe cases, the lymphatic system can become severely damaged, leading to permanent disability.
5. Treatment and Prevention:
- There is no cure for elephantiasis, but treatment can help manage symptoms and prevent complications.
- Antiparasitic medications, such as diethylcarbamazine (DEC) and ivermectin, are commonly used to kill the worms and reduce transmission.
- Mosquito control measures, such as using bed nets, insect repellents, and eliminating breeding sites, can help prevent the spread of the disease.
In conclusion, elephantiasis disease can have long-term effects on our health, causing physical and psychological distress, mobility issues, and complications associated with chronic inflammation and infections. It is important to prioritize prevention and treatment strategies to minimize the impact of this debilitating disease.

Ascaris worm lives in the small intestine of the human body.
Explanation:
The Ascaris worm, also known as the roundworm, is a common parasitic worm that infects humans. It has a complex life cycle that involves both humans and soil.
Here is a detailed explanation of where the Ascaris worm lives in the human body:
1. Small intestine:
- The adult Ascaris worm primarily resides in the lumen of the small intestine.
- It attaches itself to the intestinal wall using its mouthparts and feeds on the nutrients present in the host's digested food.
- The worm can grow up to 35 cm in length and can live for up to two years in the small intestine.
Other aspects to consider:
- The Ascaris worm does not live in the kidneys, liver, or large intestine.
- While it primarily inhabits the small intestine, the worm can occasionally migrate to other parts of the body, such as the bile ducts, pancreatic ducts, or appendix.
- The eggs of the Ascaris worm are passed in the host's feces and can contaminate the soil.
- Ingestion of contaminated food or water can lead to the infection of new hosts, perpetuating the life cycle of the worm.
Summary:
The Ascaris worm lives in the small intestine of the human body, where it feeds on nutrients from the host's digested food. It has a complex life cycle involving humans and soil, with the eggs being passed in feces and contaminating the environment. Understanding the lifecycle and habitat of the Ascaris worm is crucial for prevention, diagnosis, and treatment of the infection.

Microbes which enter the body through nose most likely affect the lungs:
- The nose is the primary entry point for many microbes, including bacteria, viruses, and fungi.
- When these microbes enter the body through the nose, they can travel through the respiratory tract and reach the lungs.
- The respiratory tract consists of the nose, throat, windpipe (trachea), and the lungs.
- The lungs are responsible for the exchange of oxygen and carbon dioxide in the body.
- Microbes that reach the lungs can cause various respiratory infections and diseases, such as pneumonia, bronchitis, influenza, and tuberculosis.
- These infections can lead to symptoms like coughing, difficulty breathing, chest pain, and fever.
- In severe cases, respiratory infections can cause significant damage to the lungs and even be life-threatening.
- It is important to note that while microbes entering through the nose can affect other organs in some cases, the lungs are the most likely target due to the direct connection between the respiratory tract and the nose.
- The liver, heart, and brain are not directly connected to the respiratory tract, making the lungs the primary organ affected by microbes entering through the nose.

Viral Infection
B: Influenza
- Influenza, commonly known as the flu, is a viral infection caused by the influenza virus.
- It affects the respiratory system and can cause symptoms such as fever, cough, sore throat, runny or stuffy nose, muscle aches, fatigue, and headaches.
- Influenza is highly contagious and can spread through droplets when an infected person coughs, sneezes, or talks.
- It can also be transmitted by touching contaminated surfaces and then touching the face.
- Influenza viruses have different strains, and they can change and mutate over time, leading to seasonal outbreaks.
- Vaccination is available to prevent influenza and is recommended annually, especially for high-risk individuals such as the elderly, young children, and people with underlying health conditions.
A: Dipteria
- Diphtheria is a bacterial infection, not a viral infection. It is caused by the bacterium Corynebacterium diphtheriae.
- It affects the respiratory system and can cause symptoms such as sore throat, fever, swollen neck glands, and difficulty breathing.
- Diphtheria is primarily spread through respiratory droplets or by direct contact with an infected person's skin or objects contaminated with the bacteria.
- Vaccination is available to prevent diphtheria, and it is typically given as part of the routine childhood immunization schedule.
C: Cholera
- Cholera is a bacterial infection caused by the bacterium Vibrio cholerae, not a viral infection.
- It primarily affects the digestive system and can cause severe diarrhea and dehydration.
- Cholera is usually transmitted through contaminated food or water.
- Vaccination against cholera exists, but it is not part of routine immunization and is mainly recommended for individuals traveling to areas with a high risk of cholera outbreaks.
D: Typhoid
- Typhoid fever is a bacterial infection caused by the bacterium Salmonella typhi, not a viral infection.
- It affects the digestive system and can cause symptoms such as fever, headache, abdominal pain, and diarrhea.
- Typhoid fever is usually transmitted through contaminated food or water.
- Vaccination against typhoid is available and is recommended for individuals traveling to regions where typhoid is endemic or common.
In conclusion, the viral infection among the given options is influenza (B).

HIV Virus and its Attack on the Human Body

The human immunodeficiency virus (HIV) primarily attacks the immune system of the body. Here is a detailed explanation of how the virus affects the immune system:

• Introduction




• HIV is a retrovirus that targets and infects CD4 cells, which are a type of white blood cells that play a crucial role in the immune system.


• Once inside the CD4 cells, the virus replicates itself and starts to destroy these cells, weakening the immune system.





• Impact on Immunity




• HIV primarily attacks the immune system, specifically the CD4 cells, which are responsible for coordinating the body's defense against infections.


• As the virus replicates and destroys CD4 cells, it gradually weakens the immune system, leaving the body vulnerable to various opportunistic infections and diseases.


• This weakened immune system is the hallmark of acquired immunodeficiency syndrome (AIDS), which is the advanced stage of HIV infection.





• Opportunistic Infections




• With a weakened immune system, individuals with HIV are more susceptible to opportunistic infections.


• These infections are caused by microorganisms that usually do not cause severe illness in individuals with a healthy immune system.


• Common opportunistic infections associated with HIV include pneumonia, tuberculosis, candidiasis, cytomegalovirus infection, and many others.





• Other Effects




• Besides the immune system, HIV can also affect other parts of the body:


• Although it does not directly attack the lungs, HIV weakens the immune system, making individuals more prone to lung infections such as pneumonia.


• HIV can also affect the central nervous system, leading to neurological complications such as HIV-associated neurocognitive disorders (HAND) and peripheral neuropathy.


• Additionally, HIV can cause liver damage indirectly, as the weakened immune system allows other infections such as hepatitis B and C to thrive.

In conclusion, while HIV does not directly attack the lungs, liver, or nerves, it primarily targets and weakens the immune system, leaving the body vulnerable to opportunistic infections and diseases.

Explanation:
An organism that carries pathogens is termed as a vector. Here is a detailed explanation for each of the options:
A. Host:
- A host is an organism that provides a habitat and nourishment for another organism (parasite).
- While a host can be infected by a pathogen, it does not necessarily carry the pathogen to other organisms.
B. Vector:
- A vector is an organism, typically an insect or other arthropod, that transmits a pathogen from one host to another.
- Vectors can carry pathogens such as viruses, bacteria, or parasites and spread them to other organisms.
- Examples of vectors include mosquitoes (transmitting malaria), ticks (transmitting Lyme disease), and fleas (transmitting bubonic plague).
C. Parasite:
- A parasite is an organism that lives on or in another organism (host) and benefits at the expense of the host.
- While parasites can cause diseases, they do not necessarily carry pathogens to other organisms.
D. Predator:
- A predator is an organism that hunts, kills, and feeds on other organisms.
- Predators do not carry pathogens or transmit diseases like vectors.
Therefore, the correct answer is B: vector, as a vector is the specific term used to describe an organism that carries pathogens and transmits them to other organisms.

Diseases which are always present in certain location are called endemic diseases
Endemic diseases are those that are constantly present in a particular geographic location or population. They are characterized by a consistent and predictable pattern of occurrence over time. Here are some key points to understand about endemic diseases:
- Definition: Endemic diseases refer to illnesses that are consistently present in a particular area or population at a relatively stable rate.
- Geographic Location: Endemic diseases are specific to certain regions or locations and do not spread beyond those boundaries.
- Consistent Presence: Unlike epidemic diseases, which have sudden outbreaks and then subside, endemic diseases are always present in a particular area.
- Stable Pattern: Endemic diseases exhibit a consistent pattern of occurrence, often with predictable seasonal variations.
- Examples: Malaria is endemic to certain parts of Africa, dengue fever is endemic in tropical regions, and Lyme disease is endemic in certain areas of the United States.
It is important to distinguish endemic diseases from epidemic diseases, which are characterized by a sudden increase in the number of cases within a specific population or geographical area. Epidemics are often temporary and may result from the introduction of a new pathogen or a change in environmental conditions.
Overall, endemic diseases are a constant presence in certain locations, and understanding their patterns and causes is crucial for effective public health management and prevention strategies.

Explanation:
DPT vaccines are administered to develop immunity against three different diseases: Tetanus, Diphtheria, and Pertussis. Here is a detailed explanation of each disease:
Tetanus:
- Tetanus is a bacterial infection caused by the bacterium Clostridium tetani.
- It enters the body through open wounds or cuts and produces a toxin that affects the nervous system, leading to muscle stiffness and spasms.
- Tetanus can be life-threatening, especially if it affects the muscles involved in breathing.
Diphtheria:
- Diphtheria is a bacterial infection caused by the bacterium Corynebacterium diphtheriae.
- It spreads through respiratory droplets, usually from coughing or sneezing.
- Diphtheria primarily affects the throat and can lead to difficulty breathing, heart problems, and even death if left untreated.
Pertussis:
- Pertussis, also known as whooping cough, is a highly contagious bacterial infection caused by the bacterium Bordetella pertussis.
- It spreads through respiratory droplets and mainly affects the respiratory system.
- Pertussis causes severe coughing spells, often accompanied by a characteristic whooping sound when breathing in.
Conclusion:
DPT vaccines, also known as DTaP vaccines, are administered to provide protection against Tetanus, Diphtheria, and Pertussis. These vaccines contain inactivated or weakened forms of the bacteria or their toxins, which stimulate the immune system to produce antibodies and develop immunity against these diseases. It is important to follow the recommended vaccination schedule to ensure adequate protection.

Why are anti-viral drugs difficult to make?
There are several reasons why anti-viral drugs are difficult to make, and these can be summarized as follows:
1. Viruses use the host's cells to replicate:
- Viruses are intracellular parasites that require host cells to replicate and multiply.
- They hijack the cellular machinery of the host cells, using their resources and energy to produce new virus particles.
- This makes it challenging to develop drugs that specifically target the virus without harming the host cells.
2. Viruses live inside the host cells:
- Once a virus enters a host organism, it invades the host cells and establishes itself within them.
- This intracellular location provides protection to the virus, making it difficult for drugs to reach and target the virus directly.
- Anti-viral drugs need to be able to penetrate the host cell and reach the virus without causing harm to the host.
3. Viruses do not live in consumed food particles:
- Viruses are not typically found in consumed food particles. Instead, they are usually transmitted through direct contact, respiratory droplets, or bodily fluids.
- Therefore, anti-viral drugs cannot be developed by targeting the viruses present in food particles.
4. Viruses can circulate in the bloodstream:
- Some viruses can spread throughout the body via the bloodstream.
- This makes it challenging to deliver drugs to the specific sites of viral infection, as the drugs need to be able to penetrate the bloodstream and reach the infected tissues or organs.
In conclusion, anti-viral drugs are difficult to make because viruses use the host's cells to replicate, live inside the host cells, do not live in consumed food particles, and can circulate in the bloodstream. These factors pose significant challenges in developing drugs that can effectively target and eliminate viruses while minimizing harm to the host organism.

BCG Vaccine and Immunity Against Tuberculosis
The BCG (Bacillus Calmette-Guérin) vaccine is primarily used to develop immunity against tuberculosis (TB). Here's a detailed explanation of how the BCG vaccine works and its role in preventing TB:
1. What is BCG Vaccine?
The BCG vaccine is made from a weakened strain of bacteria called Mycobacterium bovis, which is closely related to the bacteria that cause tuberculosis. It was developed to provide protection against TB by stimulating the body's immune response.
2. Immune Response and Tuberculosis
When a person is exposed to the bacteria that cause TB, their immune system usually responds by activating immune cells to attack and destroy the bacteria. However, in some cases, the immune response is not strong enough to eliminate the bacteria, leading to the development of active TB disease.
3. How BCG Vaccine Works
The BCG vaccine is administered to individuals to stimulate their immune system and enhance their natural defense against TB. It helps in developing immunity by:
- Introducing weakened bacteria: The BCG vaccine contains live but weakened bacteria that do not cause disease in healthy individuals. When the vaccine is injected, it establishes a mild infection in the body, which triggers an immune response.
- Activating immune cells: The weakened bacteria in the BCG vaccine stimulate the immune system, specifically the activation of immune cells called T cells. These T cells play a crucial role in recognizing and attacking the bacteria that cause TB.
- Forming immune memory: The immune response triggered by the BCG vaccine results in the formation of memory T cells. These memory cells "remember" the bacteria and quickly respond if the individual is later exposed to TB, providing a rapid and efficient immune defense.
4. Limitations of BCG Vaccine
While the BCG vaccine is effective in preventing severe forms of TB in children, it has certain limitations:
- Varied effectiveness: The BCG vaccine's effectiveness in preventing TB can vary depending on factors such as geographic location, age, and strain of TB bacteria.
- Limited protection against pulmonary TB: The BCG vaccine provides limited protection against pulmonary TB, which is the most common form of the disease.
- No protection against latent TB: The BCG vaccine does not provide protection against latent TB infection, where the bacteria are present in the body but are not causing active disease.
In conclusion, the BCG vaccine is primarily used to develop immunity against tuberculosis. It works by introducing weakened bacteria, activating immune cells, and forming immune memory. While it has limitations, it remains an important tool in preventing severe forms of TB, especially in children.

Communicable Disease:
Cholera
Explanation:
Cholera is a communicable disease caused by the bacterium Vibrio cholerae. It is primarily transmitted through contaminated water or food, particularly in areas with poor sanitation and hygiene practices. Here is a detailed explanation of why the other options are not communicable diseases:
- Rickets: Rickets is a disorder caused by a deficiency of vitamin D, calcium, or phosphate. It is not a communicable disease as it is not caused by an infectious agent and cannot be transmitted from person to person.
- Scurvy: Scurvy is a condition caused by a deficiency of vitamin C. Similar to rickets, it is not a communicable disease as it is not caused by an infectious agent and cannot be transmitted from person to person.
- Marasmus: Marasmus is a severe form of malnutrition, usually seen in children, characterized by energy deficiency and wasting of body tissues. It is not a communicable disease as it is not caused by an infectious agent and cannot be transmitted from person to person.
In summary, while rickets, scurvy, and marasmus are all health conditions, they are not communicable diseases as they are not caused by infectious agents and cannot be transmitted from person to person. Cholera, on the other hand, is highly communicable and can spread rapidly through contaminated water or food sources.

The causative organism for malaria is a protozoa.
Explanation:
Malaria is a disease caused by a parasite called Plasmodium. This parasite belongs to the kingdom Protista, specifically the phylum Apicomplexa. Within this phylum, there are several species of Plasmodium that can cause malaria in humans, including Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale.
Here's a detailed explanation of why the answer is B (protozoa):
1. Malaria is caused by the Plasmodium parasite, which is a type of protozoa. Protozoa are single-celled organisms that belong to the kingdom Protista.
2. Bacteria (A) are another type of single-celled organisms, but they are distinct from protozoa. They have their own kingdom, called Bacteria.
3. Viruses (C) are not considered living organisms because they cannot reproduce on their own. They require a host cell to replicate.
4. Fungi (D) are a separate kingdom of organisms that include molds, yeasts, and mushrooms. They are not responsible for causing malaria.
In summary, the causative organism for malaria is a protozoa, specifically the Plasmodium parasite. It is important to understand the correct classification of the organism to effectively study and combat the disease.

Vaccination helps in controlling diseases because:
1. Develops resistance against the pathogen attack:
- Vaccination stimulates the immune system to produce specific antibodies against the pathogen.
- These antibodies recognize and neutralize the pathogen, preventing it from causing infection or disease.
- The immune system also develops memory cells that remember the pathogen, providing long-term protection against future infections.
2. Kills the pathogens causing disease:
- Vaccines may contain weakened or inactivated forms of the pathogen.
- When administered, the vaccine triggers an immune response, leading to the destruction of the pathogens.
- This helps eliminate the pathogens from the body, reducing the risk of disease transmission.
3. Blocks the food supplied to pathogens:
- Some vaccines work by targeting specific antigens or proteins necessary for the pathogen's survival.
- By blocking these essential components, the vaccine prevents the pathogen from obtaining the necessary nutrients or resources to replicate and cause disease.
4. Does not allow pathogens to multiply in hosts:
- Vaccines can stimulate the immune system to produce antibodies that can directly inhibit the replication of pathogens.
- This prevents the pathogens from multiplying in the host's body, limiting their ability to cause disease.
In summary, vaccination helps control diseases by developing resistance against pathogen attacks, killing pathogens, blocking their essential resources, and preventing their multiplication in hosts.

ORS is given in:

• A: Diarrhoea


• B: Measles


• C: Typhoid


• D: Tetanus

Detailed
ORS (Oral Rehydration Solution) is a specially formulated fluid that is used to treat dehydration caused by various conditions, particularly diarrhoea. Here is a detailed explanation of why ORS is given specifically for diarrhoea:
1. Diarrhoea:
Diarrhoea is a condition characterized by frequent loose or watery stools. It can lead to severe dehydration due to the loss of fluids and electrolytes from the body. ORS is given to replenish these lost fluids and electrolytes.
2. ORS Composition:
ORS contains a specific balance of glucose and electrolytes (such as sodium, potassium, and chloride) that help the body to absorb water and restore the electrolyte balance. This composition is essential for rehydration and preventing further complications.
3. Importance of ORS in Diarrhoea:
When suffering from diarrhoea, the body loses a significant amount of fluids and electrolytes. ORS helps in the following ways:
- Rehydration: ORS helps to restore the lost fluids in the body and prevent dehydration.
- Electrolyte Balance: The electrolytes present in ORS help maintain the proper balance of minerals in the body, which is crucial for various bodily functions.
- Preventing Complications: Dehydration caused by diarrhoea can lead to serious health complications, especially in children and older adults. ORS helps prevent these complications by ensuring adequate hydration.
4. Administration of ORS:
ORS is usually given orally in the form of a solution. It is recommended to take small, frequent sips of ORS instead of large quantities at once. This allows better absorption and reduces the likelihood of vomiting.
In conclusion, ORS is specifically given for diarrhoea to replenish lost fluids and electrolytes, prevent dehydration, and maintain the electrolyte balance in the body. It is an essential treatment for managing diarrhoeal episodes and preventing complications associated with dehydration.

Example of Nutritional Deficiency Disease: Rickets

• Introduction: Nutritional deficiency diseases occur when the body does not receive adequate amounts of essential nutrients, vitamins, and minerals needed for proper functioning. One such example is rickets.


• Rickets: Rickets is a condition that primarily affects children, resulting from a deficiency of vitamin D, calcium, or phosphate.


• Cause: Rickets is caused by insufficient exposure to sunlight (which helps the body produce vitamin D), inadequate dietary intake of vitamin D, calcium, or phosphate, or impaired absorption of these nutrients.


• Symptoms: The common symptoms of rickets include bone pain, delayed growth, soft and weak bones, muscle weakness, dental problems, and skeletal deformities.


• Effects: If left untreated, rickets can lead to serious complications such as bone fractures, skeletal deformities (such as bowed legs or knock knees), stunted growth, and developmental delays.


• Treatment: Treatment for rickets typically involves correcting the underlying nutritional deficiencies. This may include increasing vitamin D intake through sunlight exposure or supplements, ensuring an adequate intake of calcium and phosphate, and making dietary modifications.


• Prevention: Rickets can be prevented by ensuring proper nutrition and adequate exposure to sunlight. A well-balanced diet including foods rich in vitamin D, calcium, and phosphate, along with regular outdoor activities, can help prevent this condition.

Therefore, among the given options, rickets is an example of a nutritional deficiency disease. Hypertension, diabetes, and gastroenteritis are not directly caused by nutritional deficiencies, but rather have other underlying causes.

Calcium deficiency occurs in the absence of vitamin D.
There is a strong connection between calcium and vitamin D in the body. Vitamin D helps the body absorb and utilize calcium effectively. Without adequate levels of vitamin D, calcium cannot be properly absorbed and utilized, resulting in a calcium deficiency.
Here is a detailed explanation of why calcium deficiency occurs in the absence of vitamin D:
1. Vitamin D and calcium absorption:
- Vitamin D plays a crucial role in calcium absorption from the intestines.
- It helps the small intestine absorb calcium by increasing the production of calcium-binding proteins.
- These proteins transport calcium across the intestinal cells and into the bloodstream.
2. Vitamin D and calcium utilization:
- Vitamin D is necessary for the body to utilize calcium effectively.
- It helps regulate calcium levels in the blood by controlling the release of parathyroid hormone (PTH).
- PTH stimulates the release of calcium from bones when blood calcium levels are low, maintaining adequate levels of calcium in the blood.
3. Calcium deficiency symptoms:
- Inadequate calcium intake or absorption can lead to calcium deficiency.
- Symptoms of calcium deficiency include muscle cramps, weak bones (osteoporosis), brittle nails, and dental problems.
4. Vitamin D deficiency:
- When the body lacks sufficient vitamin D, calcium absorption and utilization are impaired.
- This can lead to a decrease in calcium levels in the blood, resulting in calcium deficiency symptoms.
5. Sources of vitamin D:
- The primary source of vitamin D is sunlight exposure.
- It can also be obtained from certain foods such as fatty fish (salmon, mackerel), fortified dairy products, and egg yolks.
- In some cases, supplementation may be necessary to maintain adequate vitamin D levels.
In conclusion, calcium deficiency occurs in the absence of vitamin D because vitamin D is essential for calcium absorption and utilization in the body.

Fever, delirium, slow pulse, abdominal tenderness, and rose-colored rash indicate the disease typhoid.
Typhoid is a bacterial infection caused by the bacterium called Salmonella typhi. It is primarily transmitted through contaminated food and water. The symptoms usually appear about 1-3 weeks after exposure and can vary in severity.
Here is a detailed explanation of why the given symptoms indicate typhoid:
1. Fever: Typhoid fever is characterized by a prolonged and high-grade fever that can last for several weeks. The temperature can spike up to 104°F or higher.
2. Delirium: Delirium refers to a state of confusion and disorientation. It is a common symptom of typhoid fever, particularly in severe cases. Delirium can manifest as mental confusion, hallucinations, and agitation.
3. Slow pulse: Typhoid fever can cause bradycardia, which is a slower than normal heart rate. This can be observed as a slow pulse, with the heart rate often below 60 beats per minute.
4. Abdominal tenderness: Typhoid fever can cause abdominal pain and tenderness. The pain is usually located in the lower right quadrant of the abdomen and can be associated with an enlarged liver and spleen.
5. Rose-colored rash: A characteristic rose-colored rash known as "rose spots" can appear on the abdomen and chest in some cases of typhoid fever. These rash spots are small, pink, and slightly raised.
By considering the combination of these symptoms, along with a history of exposure to contaminated food or water, a healthcare professional can make a diagnosis of typhoid fever and initiate appropriate treatment. It is important to seek medical attention promptly if these symptoms are present.

Explanation:
The correct answer is B: AIDS - Bacterial infection because AIDS is not caused by a bacterial infection but by the human immunodeficiency virus (HIV).
Here is a detailed explanation for each option:
A: Leprosy - Bacterial infection
- Leprosy is caused by Mycobacterium leprae, a bacterium that affects the skin, peripheral nerves, and mucous membranes.
B: AIDS - Bacterial infection
- This is a mismatch because AIDS (Acquired Immunodeficiency Syndrome) is caused by the human immunodeficiency virus (HIV), not a bacterial infection.
C: Malaria - Protozoan infection
- Malaria is a disease caused by Plasmodium parasites, which are protozoan organisms transmitted through the bites of infected mosquitoes.
D: Elephantiasis - Nematode infection
- Elephantiasis, also known as lymphatic filariasis, is caused by the filarial nematode worms transmitted by mosquito bites.
In summary, the mismatch in the given options is B: AIDS - Bacterial infection. AIDS is caused by a viral infection, specifically the human immunodeficiency virus (HIV), not a bacterial infection.

Typhoid is caused by Salmonella.
Salmonella is a type of bacteria that causes typhoid fever, a serious and potentially life-threatening illness. Here is a detailed explanation of how Salmonella causes typhoid:
1. Salmonella bacteria enter the body:
- The bacteria enter the body through the ingestion of contaminated food or water.
- This can occur if the food or water is contaminated with feces or urine from an infected person or carrier.
2. Bacterial invasion of the intestines:
- Once inside the body, Salmonella bacteria invade the small intestine.
- They attach to the intestinal lining and penetrate the epithelial cells, gaining entry into the bloodstream.
3. Spread through the bloodstream:
- The bacteria can now spread throughout the body via the bloodstream.
- They can reach various organs and tissues, including the liver, spleen, and lymph nodes.
4. Replication and symptoms:
- Salmonella bacteria replicate within the organs, leading to the characteristic symptoms of typhoid fever.
- These symptoms may include high fever, headache, stomach pain, weakness, and loss of appetite.
5. Shedding of bacteria:
- Infected individuals can shed Salmonella bacteria in their feces, which can contaminate the environment and spread the infection to others.
6. Diagnosis and treatment:
- Diagnosis of typhoid fever is typically done through blood or stool tests to detect the presence of Salmonella bacteria or their antigens.
- Treatment involves antibiotics to kill the bacteria and supportive measures to manage symptoms and prevent complications.
In conclusion, typhoid is caused by the Salmonella bacteria, which enter the body through contaminated food or water and spread through the bloodstream, leading to systemic infection and the characteristic symptoms of typhoid fever.

Immuno-deficiency syndrome could develop due to AIDS virus
Explanation:
The immune system plays a crucial role in defending the body against infections and diseases. Immuno-deficiency syndrome, commonly known as AIDS (Acquired Immuno-Deficiency Syndrome), is a condition that occurs when the immune system becomes severely compromised. This allows various infections and diseases to attack the body, which would normally be fought off by a healthy immune system.
The main cause of immuno-deficiency syndrome is the AIDS virus (HIV), which can be transmitted through:
- Unprotected sexual intercourse with an infected individual
- Sharing needles or syringes with an infected person
- From an infected mother to her child during childbirth or breastfeeding
Once the AIDS virus enters the body, it specifically attacks the immune system by:
- Infecting and destroying CD4+ T cells, which are crucial for coordinating the immune response
- Replicating itself within the CD4+ T cells, leading to their depletion
- Weakening the immune system's ability to fight off infections and diseases
Consequences of immuno-deficiency syndrome:
- Increased susceptibility to opportunistic infections, such as pneumonia, tuberculosis, and fungal infections
- Development of certain types of cancers, including Kaposi's sarcoma and lymphomas
- Progressive decline in the immune system's function, leading to various complications and eventually death if left untreated
Treatment and prevention:
- Antiretroviral therapy (ART) is the standard treatment for immuno-deficiency syndrome, helping to control the replication of the virus and restore immune function.
- Prevention strategies include practicing safe sex, using sterile needles, and getting tested regularly for HIV.

The BCG vaccine is given for the immunity against Tuberculosis.
The BCG vaccine is a vaccine that provides immunity against tuberculosis (TB), a bacterial infection caused by Mycobacterium tuberculosis. Here are some key points to explain why the BCG vaccine is given for immunity against tuberculosis:
1. Tuberculosis (TB) and its impact:
- Tuberculosis is a contagious disease that primarily affects the lungs but can also affect other parts of the body.
- It spreads through the air when an infected individual coughs, sneezes, or talks.
- TB can cause symptoms such as persistent cough, chest pain, weight loss, fatigue, and fever.
- If left untreated, TB can be life-threatening and can cause severe health complications.
2. The BCG vaccine:
- The BCG vaccine is derived from a weakened strain of Mycobacterium bovis, a bacterium closely related to Mycobacterium tuberculosis.
- It is named after Bacillus Calmette-Guérin, the French scientists who developed the vaccine in the early 20th century.
- The BCG vaccine is administered through a small injection into the upper arm.
- It stimulates the immune system to produce a protective immune response against the bacteria that cause TB.
3. Effectiveness of the BCG vaccine:
- The BCG vaccine is primarily given to infants and young children in countries with a high prevalence of TB.
- It provides partial protection against severe forms of TB, such as TB meningitis and miliary TB, in children.
- However, the BCG vaccine's effectiveness in preventing pulmonary TB (the most common form of TB) in adults is variable and may wane over time.
- It is important to note that the BCG vaccine is not a substitute for other preventive measures, such as proper hygiene, infection control, and treatment of active TB cases.
In conclusion, the BCG vaccine is given to provide immunity against tuberculosis, a highly contagious and potentially life-threatening disease. While it offers partial protection, it is crucial to combine the vaccine with other preventive measures to control the spread of TB effectively.

Malaria is caused by a protozoan.

• Protozoan: Malaria is caused by a microscopic parasite called a protozoan. The specific protozoan responsible for malaria is Plasmodium.


• Transmission: Malaria is transmitted through the bite of infected female Anopheles mosquitoes. When a mosquito carrying the Plasmodium parasite bites a person, it injects the parasite into the bloodstream.


• Life cycle: Once inside the body, the Plasmodium parasite travels to the liver, where it multiplies and matures. It then enters the bloodstream, where it infects red blood cells and continues to multiply.


• Symptoms: Malaria can cause a range of symptoms, including fever, chills, headache, muscle aches, fatigue, nausea, and vomiting. In severe cases, it can lead to organ failure and death.


• Prevention and treatment: Preventive measures against malaria include using mosquito nets, wearing protective clothing, and using insect repellents. Treatment typically involves anti-malarial medications to kill the parasite in the body.

Malaria is a significant global health concern, particularly in tropical and subtropical regions. It is important to take precautions to prevent mosquito bites and seek prompt medical attention if experiencing symptoms suggestive of malaria.

Explanation:
The vitamin that is not fat soluble is vitamin B complex.
Reasoning:
To determine which vitamin is not fat soluble, we need to understand the difference between fat-soluble and water-soluble vitamins:
- Fat-soluble vitamins are absorbed through the intestinal tract with the help of fats and are stored in the body's fatty tissues. They can be stored in the body for longer periods of time and are not easily excreted. The fat-soluble vitamins include vitamins A, D, E, and K.
- Water-soluble vitamins, on the other hand, dissolve in water and are not stored in the body. They are easily excreted through urine. The water-soluble vitamins include the B complex vitamins (B1, B2, B3, B5, B6, B7, B9, and B12) and vitamin C.
Based on this information, we can conclude that the vitamin that is not fat soluble is vitamin B complex.
Therefore, the answer is B: vitamin B complex.

The reduced osmolarity ORS containing 75 mEq/l sodium, 75 mmol/l glucose (total osmolarity of 245 mOsm/l) is as effective as standard ORS in adults with cholera. However, it is associated with an increased incidence of transient, asymptomatic hyponatraemia.

Sunlight enhances the production of Vitamin D
Sunlight plays a crucial role in the production of Vitamin D in our bodies. Here's a detailed explanation of how sunlight affects the production of Vitamin D:
1. Sunlight and Vitamin D synthesis:
- When our skin is exposed to sunlight, a specific type of ultraviolet B (UVB) radiation penetrates the skin.
- This UVB radiation stimulates a chemical reaction in the skin, converting a substance called 7-dehydrocholesterol into Vitamin D3 (cholecalciferol).
2. Activation of Vitamin D:
- Vitamin D3, which is produced in the skin, is then converted into its active form by the liver and kidneys.
- The liver converts Vitamin D3 into calcidiol (25-hydroxyvitamin D), and the kidneys further convert it into calcitriol (1,25-dihydroxyvitamin D).
- Calcitriol is the active form of Vitamin D that is responsible for carrying out various functions in the body.
3. Importance of Vitamin D:
- Vitamin D is essential for maintaining healthy bones and teeth as it helps in the absorption of calcium and phosphorus from the diet.
- It also plays a role in regulating the immune system, promoting cell growth, and reducing inflammation.
- Adequate levels of Vitamin D are crucial for overall health and well-being.
4. Sun exposure and Vitamin D production:
- The amount of Vitamin D produced in the body depends on various factors such as the time of day, season, latitude, skin color, and amount of exposed skin.
- The best time to get sunlight for Vitamin D synthesis is when the sun is at its peak, typically between 10 am and 3 pm.
- It is important to note that excessive sun exposure without proper protection can lead to sunburn and increase the risk of skin cancer. It is recommended to balance sun exposure with sun safety measures, such as wearing sunscreen and protective clothing.
Therefore, sunlight enhances the production of Vitamin D in our bodies, which is essential for several physiological functions.

An insect which transmits a disease is known as a vector.
Explanation:
Insects play a crucial role in the transmission of diseases, acting as carriers or vectors. They can transmit pathogens, such as viruses, bacteria, or parasites, from one host to another. Here, we specifically refer to insects that transmit diseases to humans.
Key Points:
- An insect that transmits a disease is called a vector.
- Vectors can transmit diseases through their bites, feces, or contact with contaminated surfaces.
- Mosquitoes, ticks, fleas, and flies are common examples of disease vectors.
- Vectors can acquire pathogens by feeding on infected individuals or by coming into contact with contaminated materials.
- The transmission of diseases by vectors is a significant concern worldwide, contributing to the spread of illnesses such as malaria, dengue fever, Zika virus, Lyme disease, and more.
- Controlling vectors through insecticide use, proper sanitation, and personal protective measures is crucial in preventing the spread of vector-borne diseases.
- Vector control programs often focus on reducing vector populations, interrupting their breeding cycles, and minimizing human exposure to vectors.
Overall, understanding vectors and their role in disease transmission is essential for effective disease prevention and control strategies.

Communicable Disease:
A communicable disease is an illness caused by an infectious agent or its toxic products that can be transmitted from one person to another, directly or indirectly. These diseases can be spread through various means such as air, water, food, bodily fluids, or vectors like insects. One example of a communicable disease is Malaria.
Malaria:
Malaria is a life-threatening disease caused by the Plasmodium parasite. It is primarily transmitted to humans through the bite of infected female Anopheles mosquitoes. Here are some key points about Malaria:
1. Transmission: Malaria is spread through the bites of infected mosquitoes. When a mosquito bites an infected person, it ingests the parasite along with the person's blood. The parasite then multiplies inside the mosquito.
2. Human Infection: When an infected mosquito bites a healthy person, it injects the parasite into their bloodstream. The parasites then travel to the liver, mature, and eventually infect red blood cells.
3. Symptoms: Malaria symptoms include fever, chills, headache, muscle aches, fatigue, and vomiting. In severe cases, it can lead to organ failure, coma, and even death.
4. Geographic Distribution: Malaria is prevalent in tropical and subtropical regions, particularly in Africa, Asia, and Latin America.
5. Prevention: Preventive measures include the use of bed nets, insect repellents, and antimalarial drugs. Mosquito control programs, such as eliminating breeding sites and insecticide spraying, also help reduce transmission.
6. Treatment: Antimalarial medications are used for the treatment of malaria. The choice of medication depends on the type of malaria parasite and the severity of the disease.
Malaria is an example of a communicable disease because it can be transmitted from an infected person to a healthy person through the bites of infected mosquitoes. Understanding the mode of transmission helps in implementing effective prevention and control strategies to reduce the spread of the disease.

Answer:
The disease that is not communicable is leukemia. Leukemia is a type of cancer that affects the blood and bone marrow. Unlike the other diseases listed, leukemia is not caused by an infectious agent and cannot be directly transmitted from person to person.
Explanation:
Leukemia is a complex disease that arises from genetic mutations in the cells of the bone marrow. It leads to the abnormal production of white blood cells, which affects the body's ability to fight infection. However, leukemia itself is not contagious and cannot be spread through contact or exposure to an infected individual.
On the other hand, the other diseases listed in the options are communicable or infectious diseases. Here is a breakdown of the communicable nature of these diseases:
1. Typhoid: Typhoid is caused by the bacterium Salmonella typhi and is primarily transmitted through the ingestion of contaminated food or water. It can be spread from person to person through the fecal-oral route, where an infected individual sheds the bacteria in their feces and contaminates the environment.
2. Leprosy: Leprosy is caused by the bacterium Mycobacterium leprae and is primarily transmitted through prolonged close contact with an infected person. It is thought to spread through respiratory droplets when an infected individual coughs or sneezes.
3. Measles: Measles is caused by the measles virus and is highly contagious. It is transmitted through respiratory droplets when an infected individual coughs or sneezes. Measles can also spread through direct contact with infected respiratory secretions or by touching surfaces contaminated with the virus.
In summary, while typhoid, leprosy, and measles are all communicable diseases, leukemia is not. Leukemia is a non-communicable disease that is caused by genetic mutations and cannot be transmitted from person to person.

Congenital diseases are those which are present from the time of birth.
Definition:
Congenital diseases, also known as congenital disorders or birth defects, are conditions or abnormalities that are present in a baby at the time of birth. These conditions can be caused by genetic factors, environmental factors, or a combination of both.
Characteristics of congenital diseases:
- Present at birth: Congenital diseases are present in the baby from the moment of birth.
- Developmental abnormalities: These conditions often involve abnormalities in the structure or function of various organs or body systems.
- Varying severity: Congenital diseases can range from mild to severe, with some conditions being life-threatening.
- May be genetic or environmental: Some congenital diseases are caused by genetic mutations or inherited traits, while others are the result of exposure to certain environmental factors during pregnancy.
- Not contagious: Unlike diseases that are spread from person to person, congenital diseases are not contagious and cannot be transmitted from one individual to another.
- Lifelong impact: Many congenital diseases have long-term or lifelong effects on the affected individual's health and well-being.
Examples of congenital diseases:
- Down syndrome
- Cleft lip and palate
- Congenital heart defects
- Spina bifida
- Clubfoot
- Cystic fibrosis
- Muscular dystrophy
Conclusion:
Congenital diseases are conditions or abnormalities that are present in a baby from the time of birth. They can be caused by genetic or environmental factors and often have a lifelong impact on the affected individual. It is important for medical professionals to diagnose and manage congenital diseases early on to provide appropriate treatment and support to those affected.