Common Diseases in Humans — Revision Notes

⚡ 30-Second Revision

Typhoid: — *Salmonella typhi*, contaminated food/water, Widal test, high fever, constipation.
Pneumonia: — *Streptococcus pneumoniae*, droplets, affects alveoli, cough, chills.
Common Cold: — Rhinoviruses, droplets/fomites, affects nose/respiratory passage, no lungs, symptomatic treatment.
Malaria: — *Plasmodium* spp., female *Anopheles* mosquito, chills, high fever, blood smear.
Amoebiasis: — *Entamoeba histolytica*, contaminated food/water, dysentery, abdominal pain.
Ascariasis: — *Ascaris lumbricoides*, contaminated food/water/soil, intestinal blockage, anemia.
Filariasis: — *Wuchereria* spp., female *Culex* mosquito, lymphatic inflammation, elephantiasis.
Ringworm: — *Microsporum* spp. (fungi), direct contact/fomites, dry scaly lesions, itching.
Infectious: — Caused by pathogens, transmissible. Non-infectious: Not by pathogens, not transmissible (e.g., Cancer, Diabetes).

2-Minute Revision

Common diseases are categorized as infectious (caused by pathogens, transmissible) or non-infectious (genetic, lifestyle, not transmissible). For infectious diseases, remember key examples: Typhoid (*Salmonella typhi*, water/foodborne, Widal test), Pneumonia (*Streptococcus pneumoniae*, droplet, affects lungs), Common Cold (Rhinoviruses, droplet/fomite, upper respiratory, no antibiotics).

Protozoan diseases include Malaria (*Plasmodium*, *Anopheles* mosquito vector, distinct life cycle, chills/fever) and Amoebiasis (*Entamoeba histolytica*, water/foodborne, dysentery). Helminthic diseases are Ascariasis (*Ascaris*, soil/foodborne, intestinal issues) and Filariasis (*Wuchereria*, *Culex* mosquito, lymphatic swelling).

Fungal diseases like Ringworm (*Microsporum*, direct contact, skin lesions) are also important. Prevention hinges on hygiene, sanitation, vector control, and vaccination. Non-infectious diseases like Cancer and Diabetes are managed through lifestyle and medical intervention.

Focus on causative agents, transmission, symptoms, and specific diagnostic tests for quick recall.

5-Minute Revision

A comprehensive review of common diseases for NEET requires a structured approach. Start by clearly distinguishing between infectious and non-infectious diseases. Infectious diseases are caused by pathogens and are transmissible, while non-infectious ones are not. For infectious diseases, categorize them by pathogen type:

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Bacterial:

* Typhoid: *Salmonella typhi*. Transmitted via contaminated food/water. Symptoms: sustained high fever, constipation, stomach pain. Diagnosis: Widal test. Prevention: sanitation, hygiene, vaccination. * Pneumonia: *Streptococcus pneumoniae*, *Haemophilus influenzae*. Transmitted via droplets. Affects alveoli (lungs fill with fluid). Symptoms: fever, chills, cough, breathing difficulty. Prevention: vaccination.

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Viral:

* Common Cold: Rhinoviruses. Transmitted via droplets/fomites. Affects nose and respiratory passage (not lungs). Symptoms: nasal congestion, sore throat, cough. No specific cure, antibiotics ineffective.

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Protozoan:

* Malaria: *Plasmodium* spp. (e.g., *P. vivax*, *P. falciparum*). Vector: female *Anopheles* mosquito. Life cycle: sporozoites (infective to human) $ightarrow$ liver $ightarrow$ merozoites $ightarrow$ RBCs (rupture, releasing hemozoin, causing chills/fever) $ightarrow$ gametocytes (infective to mosquito).

Diagnosis: blood smear. Prevention: mosquito control. * Amoebiasis: *Entamoeba histolytica*. Transmitted via contaminated food/water. Symptoms: constipation, abdominal pain, blood/mucus in stools.

Diagnosis: stool test.

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Helminthic:

* Ascariasis: *Ascaris lumbricoides* (roundworm). Transmitted via contaminated food/water/soil. Symptoms: internal bleeding, muscular pain, anemia, intestinal blockage. Diagnosis: stool test. * Filariasis (Elephantiasis): *Wuchereria bancrofti*, *W. malayi*. Vector: female *Culex* mosquito. Symptoms: chronic inflammation of lymphatic vessels, gross deformities (elephantiasis). Diagnosis: blood smear (night).

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Fungal:

* Ringworm: *Microsporum*, *Trichophyton*, *Epidermophyton*. Transmitted via direct contact/fomites. Symptoms: dry, scaly lesions, intense itching.

For non-infectious diseases like Cancer and Diabetes, remember they are not transmissible and are linked to genetics, lifestyle, and environment. Prevention focuses on healthy living. Always review the specific diagnostic tests and the general principles of prevention (hygiene, sanitation, vector control, vaccination) for each disease. Pay special attention to the *Plasmodium* life cycle and the specific vectors for vector-borne diseases.

Prelims Revision Notes

For NEET, 'Common Diseases in Humans' requires precise factual recall. Here's a summary:

I. Infectious Diseases:

Bacterial:

* Typhoid: Causative agent: *Salmonella typhi*. Transmission: Contaminated food/water. Symptoms: Sustained high fever, stomach pain, constipation, headache. Diagnosis: Widal test. Prevention: Sanitation, hygiene, vaccination. * Pneumonia: Causative agent: *Streptococcus pneumoniae*, *Haemophilus influenzae*. Transmission: Droplets. Affects: Alveoli of lungs (fluid-filled). Symptoms: Fever, chills, cough, headache, bluish lips/nails. Prevention: Vaccination.

Viral:

* Common Cold: Causative agent: Rhinoviruses. Transmission: Droplets, fomites. Affects: Nose, respiratory passage (not lungs). Symptoms: Nasal congestion, sore throat, cough. Treatment: Symptomatic, antibiotics ineffective.

Protozoan:

* Malaria: Causative agent: *Plasmodium* spp. (*P. vivax*, *P. falciparum* - most severe). Vector: Female *Anopheles* mosquito. Life Cycle: Sporozoites (infective to human) $ightarrow$ liver $ightarrow$ merozoites $ightarrow$ RBCs (rupture, hemozoin release, chills/fever) $ightarrow$ gametocytes (infective to mosquito).

Diagnosis: Blood smear. Prevention: Mosquito control. * Amoebiasis (Amoebic Dysentery): Causative agent: *Entamoeba histolytica*. Transmission: Contaminated food/water (houseflies as carriers). Symptoms: Constipation, abdominal pain, blood/mucus in stools.

Diagnosis: Stool test. Prevention: Hygiene, sanitation.

Helminthic:

* Ascariasis: Causative agent: *Ascaris lumbricoides* (roundworm). Transmission: Contaminated food/water/soil. Symptoms: Internal bleeding, muscular pain, fever, anemia, intestinal blockage. Diagnosis: Stool test.

* Filariasis (Elephantiasis): Causative agent: *Wuchereria bancrofti*, *W. malayi*. Vector: Female *Culex* mosquito. Symptoms: Chronic inflammation of lymphatic vessels (lower limbs, genital organs), leading to gross deformities (elephantiasis).

Diagnosis: Blood smear (night).

Fungal:

* Ringworm: Causative agent: Fungi (*Microsporum*, *Trichophyton*, *Epidermophyton*). Transmission: Direct contact, fomites, soil. Symptoms: Dry, scaly lesions, intense itching. Prevention: Hygiene.

II. Non-Infectious Diseases:

Cancer: — Uncontrolled cell growth, metastasis. Causes: Carcinogens (physical, chemical, biological), genetics. Treatment: Surgery, chemo, radiation.
Diabetes: — High blood sugar. Types: Type 1 (autoimmune), Type 2 (insulin resistance). Prevention: Healthy lifestyle.

Key Concepts: Pathogen, Vector, Immunity, Vaccination, Antibiotics (for bacteria), Antivirals (for viruses). Remember that antibiotics are ineffective against viral infections.

Vyyuha Quick Recall

My Aunt Pam Told Cousin Frank Remember All Diseases:

Malaria: *Anopheles* mosquito, *Plasmodium*
Amoebiasis: Contaminated food/water, *Entamoeba histolytica*
Pneumonia: Droplets, *Streptococcus pneumoniae*
Typhoid: Contaminated food/water, *Salmonella typhi*
Common Cold: Droplets/fomites, Rhinoviruses
Filariasis: *Culex* mosquito, *Wuchereria*
Ringworm: Fungi (*Microsporum*), direct contact
Ascariasis: Contaminated food/water/soil, *Ascaris lumbricoides*
Diabetes/Cancer: Non-infectious