Infectious Diseases(Communicable)

Infectious Diseases(Communicable) are illnesses caused by microorganisms that can spread from one host to another, studied in Biology to understand their causes, transmission, and prevention. These include Viral, Bacterial, Fungal, Parasitic, Protozoan, Waterborne, Vector-borne, and Airborne diseases, each affecting human health in different ways.

Infectious Diseases(Communicable)

Communicable diseases, also known as infectious diseases, are diseases that can spread from one person to another or from animals to humans. They are caused by microorganisms such as bacteria, viruses, fungi, and parasites. These diseases can spread directly (from person to person) or indirectly (through contaminated objects, water, or air).

Modes of Transmission

1. Direct Transmission: Direct contact with an infected person or their bodily fluids.
   • Examples:
     • Touching: Skin-to-skin contact, such as in the case of chickenpox, herpes, or flu.
     • Sexual contact: Transmission of sexually transmitted diseases (STDs) like HIV/AIDS, gonorrhea, and syphilis.
     • Blood transfusions or sharing needles: Infections like HIV, hepatitis B and C.
2. Indirect Transmission: The disease spreads through a medium, such as air, water, food, or contaminated surfaces.
   • Examples:
     • Airborne transmission: Diseases like tuberculosis (TB), influenza (flu), and COVID-19 are transmitted through respiratory droplets in the air.
     • Waterborne transmission: Infections like cholera, dysentery, and typhoid fever spread through contaminated water.
     • Foodborne transmission: Diseases like food poisoning, salmonella, and hepatitis A are caused by consuming contaminated food.
     • Vector-borne transmission: Diseases like malaria, dengue, and Zika virus are spread by vectors, like mosquitoes.

Types of Communicable Diseases

1. Viral Diseases

These diseases are caused by viruses, which are microscopic pathogens that infect living cells. They often require a host to reproduce.

• Examples: Influenza (Flu), COVID-19, Measles, Chickenpox (Varicella), HIV/AIDS, Hepatitis (A, B, C, etc.),Rabies, Dengue Fever, Polio

2. Bacterial Diseases

These diseases are caused by bacteria, which are single-celled organisms that can multiply inside the human body. Some bacteria are harmful and cause diseases, while others are harmless or beneficial.

• Examples: Tuberculosis (TB), Cholera, Diphtheria, Pneumonia, Typhoid Fever, Bacterial Meningitis, Leprosy, Whooping Cough (Pertussis)

3. Fungal Diseases

Fungal infections are caused by fungi, which can live on the skin, nails, or mucous membranes of the human body. Some fungi are opportunistic pathogens, causing illness when the immune system is weakened.

• Examples: Ringworm, Candidiasis (Yeast infection), Aspergillosis, Histoplasmosis, Athlete’s Foot

4. Parasitic Diseases

These diseases are caused by parasites, which are organisms that live on or inside another organism (host) and rely on it for survival.

• Examples:
  • Malaria (caused by Plasmodium, transmitted by Anopheles mosquitoes)
  • Giardiasis (caused by Giardia, transmitted through contaminated water)
  • Amoebiasis (caused by Entamoeba histolytica)
  • Lymphatic Filariasis (caused by filarial worms, transmitted by mosquitoes)
  • Schistosomiasis (caused by Schistosoma parasites)
  • Leishmaniasis (caused by Leishmania parasites, transmitted by sandflies)

5. Protozoan Diseases

Protozoa are single-celled organisms that can cause infections when they invade human tissues. These diseases are often transmitted by vectors like mosquitoes or contaminated food and water.

• Examples:
  • Malaria (caused by Plasmodium protozoa)
  • Amoebic Dysentery
  • Chagas Disease (caused by Trypanosoma parasites, transmitted by triatomine bugs)
  • Leishmaniasis (caused by Leishmania protozoa, transmitted by sandflies)

6. Waterborne Diseases

These diseases are caused by pathogens found in contaminated water. They are spread when individuals consume or come into contact with polluted water.

• Examples:
  • Cholera (bacterial)
  • Typhoid Fever (bacterial)
  • Giardiasis (protozoan)
  • Amoebiasis (protozoan)

7. Vector-borne Diseases

These diseases are transmitted by vectors such as mosquitoes, ticks, or fleas, which carry pathogens from one host to another.

• Examples:
  • Malaria (transmitted by Anopheles mosquitoes)
  • Dengue Fever (transmitted by Aedes mosquitoes)
  • Zika Virus (transmitted by Aedes mosquitoes)
  • Yellow Fever (transmitted by Aedes and Haemagogus mosquitoes)
  • Lyme Disease (transmitted by ticks)
  • Plague (transmitted by fleas, caused by Yersinia pestis)

8. Airborne Diseases

These diseases are spread through the air, typically through respiratory droplets when an infected person coughs, sneezes, or talks.

• Examples: Tuberculosis (TB), Measles, Influenza (Flu), Chickenpox (Varicella), COVID-19, Whooping Cough (Pertussis

Viral Diseases

Viral diseases are caused by viruses, which are tiny infectious agents that need to invade living cells in order to reproduce. Unlike bacteria, viruses cannot reproduce on their own and must rely on a host’s cellular machinery to replicate. Viral infections can affect many parts of the body, and they can range from mild illnesses like the common cold to severe diseases like HIV/AIDS and COVID-19.

Common Viral Diseases

Influenza (Flu):

1. Caused by: Influenza virus (types A, B, and C).
2. Transmission: Airborne via respiratory droplets when an infected person coughs, sneezes, or talks.
3. Symptoms: Fever, chills, sore throat, cough, body aches, fatigue, runny or stuffy nose.
4. Prevention: Annual flu vaccination, good hygiene practices like handwashing, and avoiding close contact with infected individuals.
5. Treatment: Antiviral medications (e.g., oseltamivir), supportive care

COVID-19:

1. Caused by: SARS-CoV-2 virus (a type of coronavirus).
2. Transmission: Airborne through respiratory droplets, close contact, or contaminated surfaces.
3. Symptoms: Fever, dry cough, fatigue, loss of taste or smell, shortness of breath.
4. Prevention: Vaccination, wearing masks, social distancing, proper hand hygiene.
5. Treatment: Antiviral medications (e.g., remdesivir), supportive care

HIV/AIDS:

• Caused by: Human Immunodeficiency Virus (HIV).
• Transmission: Through contact with infected blood, semen, vaginal fluids, and from mother to child during childbirth or breastfeeding.
• Symptoms: Early stages (fever, swollen lymph nodes, weight loss), late stages (severe immune system weakness, leading to opportunistic infections).
• Prevention: Safe sex practices, using clean needles, HIV treatment with antiretroviral drugs.
• Treatment: Antiretroviral drugs, lifelong management

Measles:

• Caused by: Measles virus.
• Transmission: Airborne via respiratory droplets or direct contact with secretions from the nose or throat.
• Symptoms: High fever, runny nose, cough, sore throat, red, blotchy rash (starting on face and spreading).
• Prevention: Measles vaccine (MMR – Measles, Mumps, Rubella).

Chickenpox (Varicella):

• Caused by: Varicella-zoster virus (VZV).
• Transmission: Airborne via respiratory droplets or direct contact with skin lesions.
• Symptoms: Itchy rash with red spots and blisters, fever, tiredness.
• Prevention: Chickenpox vaccine (Varicella vaccine).
• Treatment : Antihistamines, calamine lotion, antiviral drugs (in severe cases)

Hepatitis:

• Caused by: Hepatitis viruses (A, B, C, D, and E).
• Transmission:
  • Hepatitis A: Contaminated food or water.
  • Hepatitis B and C: Blood and bodily fluids (e.g., sexual contact, sharing needles).
• Symptoms: Jaundice (yellowing of skin and eyes), fatigue, abdominal pain.
• Prevention: Vaccination (for Hepatitis A and B), safe sex practices, avoiding sharing needles.
• Treatment: Antiviral drugs (e.g., for Hepatitis B), supportive care

Polio (Poliomyelitis):

• Caused by: Poliovirus.
• Transmission: Fecal-oral route (through contaminated food or water) or respiratory droplets.
• Symptoms: Fever, fatigue, headache, vomiting, paralysis (in severe cases).
• Prevention: Polio vaccine (oral polio vaccine or IPV).
• Treatment: Supportive care (no cure for paralysis)

Rabies:

• Caused by: Rabies virus.
• Transmission: Bite or scratch from an infected animal, most commonly from dogs.
• Symptoms: Fever, headache, anxiety, hallucinations, hydrophobia (fear of water), paralysis, and death once symptoms appear.
• Prevention: Rabies vaccination for pets, post-exposure vaccination for humans after potential exposure.
• Treatment: Post-exposure prophylaxis (PEP) with rabies vaccine and immune globulin

Herpes Simplex Virus (HSV):

• Caused by: Herpes simplex virus types 1 (HSV-1) and 2 (HSV-2).
• Transmission: Direct contact with infected skin or mucous membranes, including sexual contact (for HSV-2).
• Symptoms: Painful blisters on the skin or mucous membranes, fever (in some cases).
• Prevention: Avoiding contact during outbreaks, antiviral medications.
• Treatment: Antiviral drugs (e.g., acyclovir), supportive care

Dengue Fever:

• Caused by: Dengue virus (from the Flavivirus family).
• Transmission: Through bites of infected Aedes mosquitoes.
• Symptoms: High fever, severe headache, pain behind the eyes, joint pain, rash, and nausea.
• Prevention: Avoid mosquito bites using insect repellent, mosquito nets, and eliminating standing water where mosquitoes breed.
• Treatment: Supportive care (fluids, pain relief), no specific antiviral treatment

Characteristics of Viral Infections

• Incubation Period: The time between exposure to the virus and the appearance of symptoms can vary from a few days (for flu) to weeks (for HIV).
• Symptoms: Often include fever, fatigue, cough, muscle aches, and rashes. However, each virus has its characteristic set of symptoms.
• Self-limiting vs. Chronic: Some viral infections resolve on their own (like the flu), while others, such as HIV and hepatitis, can lead to chronic conditions and long-term complications if untreated.

Viral Disease Diagnosis and Treatment

• Diagnosis: Viral infections are typically diagnosed by clinical symptoms and laboratory tests, such as PCR (Polymerase Chain Reaction), blood tests, or viral cultures.
• Treatment:
  • Antiviral medications (e.g., oseltamivir for flu, antiretrovirals for HIV) can be prescribed for some viral infections, but for many viruses, there is no specific antiviral treatment.
  • Supportive care (e.g., fluids, pain relievers) is often used to manage symptoms.
  • Vaccines (e.g., MMR, flu vaccine) are the primary method of prevention for many viral diseases.

Prevention and Control of Viral Diseases

• Vaccination:
  • Vaccines have been developed for many viruses, providing immunity and preventing outbreaks (e.g., measles, polio, hepatitis B).
• Good Hygiene:
  • Regular handwashing, avoiding close contact with infected individuals, using tissues or masks when sneezing or coughing to reduce transmission.
• Vector Control:
  • Reducing exposure to mosquitoes (for diseases like dengue and Zika) through insect repellent, nets, and eliminating mosquito breeding sites.
• Safe Practices:
  • Safe sex practices (e.g., condom use) and avoiding sharing needles or unclean medical instruments.

Bacterial diseases:

1. Tuberculosis (TB)

• Caused By: Mycobacterium tuberculosis
• Transmission: Airborne through respiratory droplets (coughing, sneezing, talking)
• Symptoms: Persistent cough (sometimes with blood), chest pain, fatigue, weight loss, night sweats, fever, coughing up blood
• Prevention:
  • BCG (Bacillus Calmette-Guérin) vaccination.
  • Good hygiene practices (covering mouth while coughing/sneezing, ventilating rooms).
  • Screening and early treatment of infected individuals.
• Treatment:
  • Long-term antibiotic treatment with medications like Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol for 6 to 9 months.
  • Directly observed therapy (DOT) to ensure compliance with the treatment regimen.

2. Cholera

• Caused By: Vibrio cholerae
• Transmission: Contaminated food or water (fecal-oral route)
• Symptoms: Severe watery diarrhea (rice-water stools), vomiting, dehydration, abdominal cramps, weakness
• Prevention:
  • Proper sanitation and water treatment (e.g., chlorination).
  • Vaccination (oral cholera vaccine available in some countries).
  • Avoiding unclean food and water.
• Treatment:
  • Oral rehydration therapy (ORT) for dehydration.
  • Antibiotics (e.g., Doxycycline or Ciprofloxacin) may be used to shorten the duration of illness.
  • Intravenous fluids for severe dehydration.

3. Diphtheria

• Caused By: Corynebacterium diphtheriae
• Transmission: Airborne droplets from coughs or sneezes, or contact with contaminated objects
• Symptoms: Sore throat, fever, swollen glands, thick gray membrane on the tonsils and throat, difficulty swallowing
• Prevention:
  • Diphtheria vaccine (DTaP).
  • Proper hygiene and avoiding close contact with infected individuals.
• Treatment:
  • Antitoxin (to neutralize the toxin produced by the bacteria).
  • Antibiotics (Penicillin or Erythromycin).
  • Hospitalization in severe cases to manage breathing difficulties.

4. Pneumonia

• Caused By: Streptococcus pneumoniae (most common), Haemophilus influenzae, Mycoplasma pneumoniae
• Transmission: Airborne through respiratory droplets (coughing, sneezing)
• Symptoms: Fever, cough, shortness of breath, chest pain, fatigue, confusion (in elderly)
• Prevention:
  • Pneumococcal vaccination (Pneumovax or Prevnar).
  • Avoiding smoking and managing chronic diseases.
  • Good hygiene and avoiding close contact with infected individuals.
• Treatment:
  • Antibiotics (e.g., Amoxicillin, Ceftriaxone, Azithromycin).
  • Oxygen therapy and mechanical ventilation (in severe cases).
  • Pain relievers and cough suppressants.

5. Typhoid Fever

• Caused By: Salmonella enterica (serotype Typhi)
• Transmission: Contaminated food or water (fecal-oral route)
• Symptoms: High fever, abdominal pain, fatigue, loss of appetite, constipation or diarrhea, rose-colored spots on the abdomen
• Prevention:
  • Vaccination (oral and injectable typhoid vaccine).
  • Safe drinking water and food hygiene.
  • Handwashing with soap.
• Treatment:
  • Antibiotics (e.g., Ciprofloxacin, Ceftriaxone, Azithromycin).
  • Fluid and electrolyte replacement.
  • Supportive care for complications (e.g., gastrointestinal bleeding or perforation).

6. Bacterial Meningitis

• Caused By: Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae type b
• Transmission: Airborne droplets, close contact (e.g., kissing, sharing utensils)
• Symptoms: Severe headache, fever, stiff neck, nausea, vomiting, confusion, sensitivity to light
• Prevention:
  • Vaccination (Meningococcal vaccine, Hib vaccine).
  • Proper hygiene practices and avoiding close contact with infected individuals.
• Treatment:
  • Antibiotics (e.g., Ceftriaxone, Penicillin, Vancomycin).
  • Corticosteroids to reduce inflammation.
  • Supportive care in the hospital, including intravenous fluids and pain management.

7. Leprosy (Hansen’s Disease)

• Caused By: Mycobacterium leprae
• Transmission: Prolonged contact with an infected person (via nasal droplets or skin contact)
• Symptoms: Skin lesions, nerve damage (numbness), muscle weakness, loss of sensation in hands and feet, disfigurement (in severe cases)
• Prevention:
  • Avoid prolonged close contact with untreated leprosy patients.
  • Early diagnosis and treatment to prevent transmission.
• Treatment:
  • Multi-drug therapy (MDT) consisting of Rifampicin, Dapsone, and Clofazimine.
  • Treatment can last for 6 months to 2 years, depending on the severity.

8. Whooping Cough (Pertussis)

• Caused By: Bordetella pertussis
• Transmission: Airborne (coughing or sneezing)
• Symptoms: Severe coughing fits followed by a “whooping” sound, runny nose, mild fever, vomiting after coughing fits
• Prevention:
  • Vaccination (DTaP for children, Tdap for adolescents and adults).
  • Good hygiene (covering mouth and nose while coughing).
• Treatment:
  • Antibiotics (e.g., Azithromycin, Erythromycin).
  • Supportive care (hydration, rest).
  • Cough suppressants and sometimes hospitalization for severe cases.

9. Gonorrhea

• Caused By: Neisseria gonorrhoeae
• Transmission: Sexual contact (vaginal, oral, anal), from mother to child during childbirth
• Symptoms: Painful urination, discharge from the genitals (yellow or green), pelvic pain in women, sore throat, rectal pain (if infected in those areas)
• Prevention:
  • Safe sex practices (using condoms).
  • Regular screenings for sexually active individuals.
• Treatment:
  • Antibiotics (e.g., Ceftriaxone, Azithromycin).
  • Treatment of sexual partners to prevent reinfection.

10. Syphilis

• Caused By: Treponema pallidum
• Transmission: Sexual contact, from mother to child during pregnancy (congenital syphilis)
• Symptoms:
  • Primary Stage: Painless sores (chancre) at the site of infection (genitals, anus, mouth).
  • Secondary Stage: Skin rashes, mucous membrane lesions, swollen lymph nodes.
  • Tertiary Stage (if untreated): Organ damage, neurological issues, cardiovascular problems.
• Prevention:
  • Safe sex practices (condom use).
  • Regular screenings for sexually active individuals.
• Treatment:
  • Antibiotics (Penicillin G is the primary treatment).
  • Early stages are easily curable with a single dose of antibiotics.

11. Plague

• Caused By: Yersinia pestis
• Transmission: Flea bites (from infected rodents), respiratory droplets (in person-to-person transmission)
• Symptoms:
  • Bubonic Plague: Swollen and painful lymph nodes (buboes), fever, chills, headache, fatigue.
  • Pneumonic Plague: Cough, chest pain, difficulty breathing, fever.
  • Septicemic Plague: Abdominal pain, bleeding, shock.
• Prevention:
  • Avoiding contact with rodents and fleas in endemic areas.
  • Good hygiene and use of insect repellents.
• Treatment:
  • Antibiotics (e.g., Streptomycin, Gentamicin).
  • Early treatment is critical to reduce mortality rate.

Fungal Disease

Fungal Disease	Caused By	Transmission	Symptoms	Prevention	Treatment
Athlete’s Foot (Tinea Pedis)	Trichophytonspecies	Direct contact with infected skin, contaminated surfaces	Itchy, red, scaly rash on feet, blisters, cracked skin, burning sensation	Keep feet clean and dry, antifungal powder in shoes, avoid walking barefoot in public areas	Topical antifungal creams (e.g., Clotrimazole, Miconazole), oral antifungals for severe cases
Ringworm (Tinea Corporis)	Trichophyton, Microsporum, Epidermophytonspecies	Direct contact with infected person, animal, or contaminated surfaces	Circular, red, itchy patches, raised edges, hair loss (scalp), flaking or peeling skin	Good hygiene, avoid sharing personal items, wear loose clothing	Topical antifungals (e.g., Clotrimazole, Terbinafine), oral antifungals for extensive cases (e.g., Griseofulvin)
Candidiasis (Thrush)	Candida albicans	Overgrowth of yeast, sexual contact, mother to baby during childbirth	Oral thrush: White patches in mouth, sore throat, Vaginal: Itching, burning, thick white discharge, Skin: Red, itchy rashes	Maintain hygiene, avoid antibiotics overuse, manage diabetes	Topical antifungal creams (e.g., Clotrimazole, Miconazole), oral antifungals (e.g., Fluconazole)
Aspergillosis	Aspergillusspecies (e.g., A. fumigatus)	Inhalation of airborne spores from decaying plant matter, soil	Cough, wheezing, shortness of breath, chest pain, hemoptysis, fatigue, weight loss, night sweats (chronic form)	Avoid mold exposure, wear masks in affected areas	Antifungal medications (e.g., Voriconazole, Itraconazole), surgery for severe cases
Histoplasmosis	Histoplasma capsulatum	Inhalation of spores from bird or bat droppings	Fever, cough, chest pain, body aches, weight loss, fatigue, difficulty breathing (severe)	Avoid bird or bat droppings, wear masks in risk areas	Antifungal drugs (e.g., Itraconazole, Amphotericin B for severe cases)
Cryptococcosis	Cryptococcus neoformans	Inhalation of spores from bird droppings	Cough, chest pain, difficulty breathing, meningitis (headache, nausea, vomiting, confusion, neck stiffness)	Avoid bird droppings, extra precautions for immunocompromised individuals	Antifungal drugs (e.g., Amphotericin B, Flucytosine, Fluconazole)
Vaginal Candidiasis	Candida albicans	Overgrowth of yeast in the vagina, antibiotics, diabetes, pregnancy	Itching, burning, thick white discharge, discomfort during intercourse or urination	Good hygiene, avoid scented products, wear breathable clothing	Topical antifungals (e.g., Clotrimazole, Miconazole), oral antifungals (e.g., Fluconazole)
Pneumocystis Pneumonia (PCP)	Pneumocystis jirovecii	Airborne transmission (inhaled spores)	Fever, cough, shortness of breath, chest pain, fatigue, difficulty breathing (especially in immunocompromised individuals)	Prophylactic treatment for immunocompromised individuals, avoid respiratory infections	Antifungal treatment (e.g., Trimethoprim-sulfamethoxazole), corticosteroids for inflammation
Blastomycosis	Blastomyces dermatitidis	Inhalation of spores from contaminated soil, decaying organic matter	Fever, cough, chest pain, fatigue, weight loss, skin lesions, joint pain	Avoid exposure to contaminated soil or decaying wood, wear masks when in high-risk environments	Antifungal medications (e.g., Itraconazole, Amphotericin B for severe cases)
Coccidioidomycosis (Valley Fever)	Coccidioides immitis, C. posadasii	Inhalation of airborne spores from dust in arid areas	Fever, cough, chest pain, fatigue, muscle aches, rash, joint pain	Avoid dust storms, wear protective masks in dusty environments	Antifungal drugs (e.g., Fluconazole, Itraconazole)

Parasitic diseases

Malaria 

Global Initiatives

1. WHO Global Malaria Program (GMP): Aiming to reduce malaria cases and deaths by 90% by 2030.
2. E-2025 Initiative: Launched by WHO in 2021. It targets malaria elimination in 25 countries by 2025.
3. Malaria Vaccines:
   • R21/Matrix-M: WHO-recommended vaccine (2024), developed by the University of Oxford and manufactured by Serum Institute of India.
   • RTS,S/AS01: The first malaria vaccine approved by WHO.

India-Specific Initiatives

1. National Framework for Malaria Elimination (2016–2030): Aims to eliminate malaria in India by 2030 and maintain malaria-free zones.
2. National Vector-Borne Disease Control Programme (NVBDCP): Implements prevention and control measures for vector-borne diseases, including malaria.
3. High Burden to High Impact (HBHI) Initiative Launched in 2019 in states with high malaria prevalence (e.g., Jharkhand, Chhattisgarh).
4. MERA-India (Malaria Elimination Research Alliance): Led by ICMR to support malaria control research in collaboration with partners.

Parasitic Disease	Caused By	Transmission	Symptoms	Prevention	Treatment
Malaria	Plasmodium species (e.g., P. falciparum, P. vivax)	Bite of infected Anopheles mosquito	Fever, chills, sweating, headache, fatigue, nausea, vomiting, anemia, jaundice	Insect repellents, bed nets, antimalarial drugs for travelers, mosquito control	Antimalarial drugs (e.g., Chloroquine, Artemisinin-based combination therapy)
Amoebiasis	Entamoeba histolytica	Contaminated food or water (fecal-oral route)	Diarrhea, abdominal pain, cramps, blood in stool, fever, weight loss	Drink clean water, maintain good hygiene, avoid eating raw food in areas with poor sanitation	Antiprotozoal drugs (e.g., Metronidazole, Tinidazole)
Giardiasis	Giardia lamblia	Contaminated water, food, or direct contact with infected individuals	Diarrhea, bloating, gas, stomach cramps, nausea, fatigue	Drink clean water, avoid swallowing water from lakes or rivers, good hygiene	Antiprotozoal drugs (e.g., Metronidazole, Tinidazole)
Leishmaniasis	Leishmaniaspecies (e.g., L. donovani, L. major)	Bite of infected Phlebotominesandfly	Cutaneous: Skin sores, ulcers; Visceral (Kala-azar): Fever, weight loss, spleen and liver enlargement, anemia	Avoid sandfly bites, use insect repellents, control sandfly populations	Antileishmanial drugs (e.g., Miltefosine, Amphotericin B)
Filariasis (Elephantiasis)	Wuchereria bancrofti, Brugia malayi(filarial worms)	Bite of infected mosquitoes (e.g., Culex, Anopheles, Aedes)	Swelling of limbs, fever, lymph node enlargement, thickening of skin	Mosquito control, use of insecticide-treated nets, mass drug administration	Antifilarial drugs (e.g., Diethylcarbamazine, Albendazole)
Schistosomiasis	Schistosomaspecies (e.g., S. mansoni, S. haematobium)	Contact with contaminated freshwater (cercariae penetrate the skin)	Abdominal pain, diarrhea, blood in stool, bladder issues, liver enlargement, fatigue, itching at infection site	Avoid contact with contaminated freshwater, improve sanitation	Antischistosomal drugs (e.g., Praziquantel)
Toxoplasmosis	Toxoplasma gondii	Ingestion of oocysts from contaminated food, water, or cat feces; congenital transmission	Flu-like symptoms, muscle pain, eye damage, encephalitis (headache, nausea, confusion, neck stiffness)	Proper hygiene when handling raw meat or cleaning cat litter, avoid contact with cat feces, especially during pregnancy	Antiprotozoal drugs (e.g., Pyrimethamine, Sulfadiazine)
Trichomoniasis	Trichomonas vaginalis	Sexual contact (human-to-human transmission)	Vaginal itching, burning, unusual discharge, painful urination in females; asymptomatic in males	Use condoms, regular screening and treatment of infected individuals	Antiprotozoal drugs (e.g., Metronidazole, Tinidazole)
Trypanosomiasis (Sleeping Sickness)	Trypanosoma brucei (e.g., T. b. gambiense, T. b. rhodesiense)	Bite of infected Tsetse fly	Fever, headache, joint pain, sleep disturbances, confusion, personality changes, neurological symptoms	Avoid tsetse fly bites, wear protective clothing, use insect repellents	Antitrypanosomal drugs (e.g., Suramin, Melarsoprol)
Ascariasis	Ascaris lumbricoides(roundworm)	Ingestion of contaminated food or water containing Ascaris eggs	Abdominal pain, nausea, vomiting, cough (due to larvae migration), weight loss	Drink clean water, practice good sanitation, avoid eating contaminated food	Anthelmintic drugs (e.g., Albendazole, Mebendazole)

Waterborne diseases

Waterborne diseases are diseases caused by the consumption or contact with contaminated water. They are usually caused by bacteria, viruses, protozoa, or parasites, and can be transmitted through the ingestion of or direct contact with contaminated water sources such as rivers, lakes, and improperly treated drinking water. Below is a list of common waterborne diseases:

1. Cholera

• Caused By: Vibrio cholerae (bacteria)
• Transmission: Ingestion of contaminated water or food
• Symptoms: Severe diarrhea, vomiting, dehydration, and electrolyte imbalance, which can lead to death if untreated
• Prevention:
  • Safe drinking water.
  • Proper sanitation and hygiene practices.
  • Oral cholera vaccines.
• Treatment:
  • Rehydration therapy (oral or intravenous fluids).
  • Antibiotics (e.g., Doxycycline) in severe cases.

2. Typhoid Fever

• Caused By: Salmonella enterica (serovar Typhi) (bacteria)
• Transmission: Ingestion of contaminated food or water
• Symptoms: High fever, weakness, abdominal pain, diarrhea, and in some cases, intestinal perforation
• Prevention:
  • Drinking safe water, proper sanitation, and good hygiene.
  • Vaccination (Typhoid vaccine).
• Treatment:
  • Antibiotics (e.g., Ciprofloxacin, Azithromycin).
  • Rehydration therapy.

3. Hepatitis A

• Caused By: Hepatitis A virus
• Transmission: Fecal-oral route, usually through contaminated water or food
• Symptoms: Fever, fatigue, abdominal pain, nausea, jaundice (yellowing of skin/eyes), dark urine
• Prevention:
  • Vaccination (Hepatitis A vaccine).
  • Proper sanitation and hygiene, especially washing hands.
  • Avoiding consumption of untreated water.
• Treatment:
  • No specific antiviral treatment, but supportive care (rest, hydration, pain relief).

4. Dysentery

• Caused By: Shigella species (bacteria) or Entamoeba histolytica (protozoa)
• Transmission: Contaminated water, food, or direct contact with infected individuals
• Symptoms: Diarrhea with blood and mucus, abdominal pain, fever
• Prevention:
  • Safe drinking water.
  • Proper sanitation and hygiene.
  • Hand washing after using the restroom.
• Treatment:
  • Antibiotics (e.g., Ciprofloxacin) for bacterial dysentery.
  • Antiprotozoal drugs (e.g., Metronidazole) for amoebic dysentery.

5. Giardiasis

• Caused By: Giardia lamblia (protozoa)
• Transmission: Ingestion of contaminated water, food, or from contact with infected individuals
• Symptoms: Diarrhea, bloating, gas, stomach cramps, nausea, fatigue
• Prevention:
  • Drink treated water, avoid drinking untreated water from lakes or rivers.
  • Wash hands before eating or preparing food.
• Treatment:
  • Antiprotozoal drugs (e.g., Metronidazole, Tinidazole).

FAQ (Previous year questions)