Common Diseases in Human

COMMON DISEASES IN HUMANS:

• Pathogens and Disease:

- Bacteria, viruses, fungi, protozoans, helminths can cause diseases.

- These disease-causing organisms are termed pathogens.

• Parasites as Pathogens:

- Most parasites are pathogens, harming the host by residing in or on them.

- Pathogens enter the body through various means, multiplying and disrupting vital activities.

• Adaptation of Pathogens:

- Pathogens must adapt to the host environment.

- Example: Gut pathogens adapt to survive in the stomach's low pH and resist digestive enzymes.

• Understanding the diversity of pathogens, their modes of entry, and adaptive strategies is crucial for devising effective preventive and therapeutic measures in the field of medicine.

Bacterial Diseases

Typhoid Fever:

• Salmonella typhi is a bacterium causing typhoid fever in humans.
• Mode of Entry:

Typically enters the small intestine through contaminated food and water.

• Spread within the Body: Migrates to other organs through the bloodstream.

• Symptoms of Typhoid Fever: Sustained high fever (39° to 40°C), weakness, stomach pain, constipation, headache, and loss of appetite.

• Severity and Complications: Severe cases may lead to intestinal perforation and, in extreme cases, death.

• Diagnostic Confirmation: Typhoid fever can be confirmed through the Widal test.

• Case Example: Typhoid Mary:

- Notable case in medical history.

- Mary Mallon (Typhoid Mary), a cook, was a carrier of typhoid and unknowingly spread the disease through the food she prepared.

- Emphasizes the importance of identifying carriers to prevent the spread of infectious diseases.

Pneumonia:

• Streptococcus pneumoniae and Haemophilus influenzae are bacteria causing pneumonia in humans.
• Affected Area: Pneumonia infects the alveoli, which are air-filled sacs in the lungs.
• Consequences of Infection: Infection leads to the filling of alveoli with fluid, causing severe respiratory issues.

• Symptoms: Common symptoms include fever, chills, cough, and headache.

• Severe Cases: In severe pneumonia, lips and fingernails may turn gray to bluish in color.

• Transmission:

- Healthy individuals can acquire the infection by inhaling droplets/aerosols released by an infected person.

• Sharing glasses and utensils with an infected person also poses a risk.

• Other Bacterial Diseases:

1. Dysentery:

Bacterial infection causes inflammation of the intestines, leading to diarrhea with blood.

2. Plague:

- Bacterial disease caused by Yersinia pestis, often transmitted through fleas.

- The historical significance of the plague, particularly the Black Death in the 14th century, lies in its profound impact on population, society, and culture.

- It led to a significant reduction in population, altering social structures, inspiring artistic expression, prompting early public health measures, influencing religious thought, and shaping urban planning practices.

- The Black Death's consequences extended across demographics, economies, and various aspects of human life, leaving a lasting imprint on history.

Diphtheria:

Bacterial infection affecting the respiratory system, causing a thick coating in the throat, leading to breathing difficulties.

Viral Diseases

Common Cold:

• Rhino Viruses:

A group of viruses causing one of the most infectious human ailments – the common cold.

• Targeted Areas:

Infect the nose and respiratory passages, distinguishing them from lung infections.

• Common Cold Characteristics:

- Characterized by nasal congestion, discharge, sore throat, hoarseness, cough, headache, and tiredness.

- Typically lasts for 3-7 days.

• Transmission:

- Spread through droplets produced by coughs or sneezes of an infected person.

- Transmission also occurs via contaminated objects like pens, books, cups, doorknobs, computer keyboards, or mouse.

• Awareness of transmission through respiratory droplets and contaminated objects emphasizes the importance of hygiene to prevent the spread of viral infections.

Protozoan Diseases

Malaria

• Causative Agent: Protozoan parasite named Plasmodium sps.
• Malaria Overview:Disease fought for many years, predominantly transmitted by infected female Anopheles mosquitoes.
• Plasmodium Species: Different types of malaria caused by various Plasmodium species: P. vivax, P. malaria, and P. falciparum.
• Severity Levels: Malignant malaria, caused by P. falciparum, is the most serious and potentially fatal.
• Life Cycle of Plasmodium:

Entry into Human Body:

- Sporozoites (infectious form) enter the human body through the bite of an infected female Anopheles mosquito.

Multiplication and Rupture:

- Parasites multiply in liver cells and later attack red blood cells (RBCs), causing their rupture.

Symptoms and Fever:

- Rupture releases a toxic substance, haemozoin, leading to recurring chills and high fever every three to four days.

Transmission to Mosquito:

- When a female Anopheles mosquito bites an infected person, parasites enter and undergo further development.

Completing the Life Cycle:

- Parasites multiply within the mosquito, forming sporozoites stored in salivary glands.

- Subsequent bites transmit sporozoites to humans, completing the cycle.

• Two-Host Requirement:

- Malarial parasite requires two hosts – human and mosquitoes – for its complete life cycle.

- Female Anopheles mosquito serves as the vector, transmitting the parasite.

Amoebiasis (Amoebic Dysentery)

• Causative Protozoan: Entamoeba histolytica, a protozoan parasite residing in the large intestine of humans.
• Disease Overview: Causes amoebiasis, commonly known as amoebic dysentery.
• Symptoms: Manifestations include constipation, abdominal pain, cramps, and stools with excessive mucus and blood clots.
• Transmission Dynamics:

- Mechanical Carriers:

Houseflies serve as mechanical carriers, transmitting the parasite from the feces of an infected person to food and food products.

- Contamination Source:

Main sources of infection are drinking water and food contaminated by fecal matter.

Transmission Route:

Houseflies contaminate food by transferring the parasite from infected feces, leading to subsequent ingestion by humans.

Helminthic Diseases

Ascariasis

• Causative Agent: Parasite: Ascaris lumbricoides, a common intestinal roundworm.

• Symptoms: Internal bleeding, muscular pain, fever, Anaemia., blockage of the intestinal passage.
• Mode of Transmission:

- Egg Dissemination:

Parasite eggs are excreted with the feces of infected individuals.

- Contamination Sources:

Contaminated soil, water, plants, etc.

- Acquisition by Healthy Individuals:

Through ingestion of contaminated water, vegetables, fruits, etc.

• Health Impact: Causes a range of symptoms affecting the gastrointestinal system and overall well-being.
• Prevention and Control:

- Hygiene Practices:

Proper sanitation to minimize fecal contamination.

Thorough washing of vegetables and fruits.

Access to clean drinking water.

- Health Education:

Raise awareness about the importance of hygiene in preventing Ascariasis.

Elephantiasis or Filariasis

• Causative Agent: Parasite: Wuchereria bancrofti and Wuchereria malayi, filarial worms.

• Characteristics: Slowly developing chronic inflammation of organs, commonly lymphatic vessels in lower limbs.
• Symptoms:

- Chronic Inflammation:

Persistent swelling due to lymphatic system disruption.

- Gross Deformities:

Particularly in the genital organs.

• Transmission: Female mosquito vectors (e.g., Culex quinquefasciatus) transmit the pathogens during a blood meal.
• Geographical Distribution: Commonly prevalent in tropical and subtropical regions.
• Health Impact: Causes long-term disability and disfigurement.
• Preventive Measures:

- Vector Control:

Mosquito control programs to reduce transmission.

- Personal Protection:

Use of bed nets and protective clothing.

- Mass Drug Administration (MDA):

Distribution of antifilarial drugs in endemic areas.

• Public Awareness: Health education campaigns emphasizing preventive measures and early treatment.

Fungal Diseases

Ringworm

• Causative Fungi: Genera Microsporum, Trichophyton, and Epidermophyton.
• Symptoms:

- Appearance of Lesions:

Dry, scaly lesions on various body parts (skin, nails, scalp).

- Accompanying Itching:

Intense itching associated with the lesions.

• Fungi Growth Conditions:

- Favorable Environment:

Thrive in heat and moisture.

- Prevalent Areas:

Skin folds like those in the groin or between toes.

• Mode of Transmission:

- Generally acquired from soil.

- Transmission through towels, clothes, or combs used by infected individuals.

• Preventive Measures:

- Regular cleaning and drying of skin folds.

- Avoid sharing personal items with infected individuals.

• Treatment: Topical or oral antifungal medications for effective treatment.

• Public Awareness: Health education campaigns on maintaining hygiene and recognizing early symptoms.

Prevention and Control of Infectious Diseases

Disease Prevention

• Personal Hygiene Measures:

- Body Cleanliness:

Regular personal cleanliness to prevent the spread of infectious agents.

- Safe Consumables:

Consumption of clean drinking water, uncontaminated food, vegetables, and fruits.

• Public Hygiene Measures:

- Waste Disposal:

Proper disposal of waste and excreta to prevent the transmission of diseases.

- Cleaning and Disinfection:

Periodic cleaning and disinfection of water reservoirs, pools, cesspools, and tanks.

- Hygiene in Public Spaces:

Observance of standard hygiene practices in public catering establishments.

• Disease-Specific Measures:

Food and Waterborne Diseases (e.g., Typhoid, Amoebiasis, Ascariasis):

- Emphasize clean food and water consumption.

- Prevent transmission through contaminated food and water.

Airborne Diseases (e.g., Pneumonia, Common Cold):

- Avoid close contact with infected persons or their belongings.

Vector-Borne Diseases (e.g., Malaria, Filariasis):

- Control or eliminate vectors and breeding places.

- Measures include water stagnation prevention, mosquito net use, introduction of mosquito-eating fishes, and insecticide spraying.

• Biological Advancements:

Vaccines and Immunization:

- Eradication of deadly diseases like smallpox through vaccination.

- Control of diseases like polio, diphtheria, pneumonia, and tetanus.

Biotechnology Contributions:

- Ongoing developments for newer and safer vaccines.

• Drug Discoveries:

- Antibiotics and Treatments:

Effective treatment of infectious diseases through antibiotic and drug discoveries.