Measles and German Measles

Measles (Rubeola)

• Morbillivirus is the causative agent
• Transmission occurs through airborne droplets or direct contact with nasal/throat secretions
• Incubation lasts 10–14 days
• Koplik's spots (tiny white spots in the mouth) are a unique diagnostic indicator
• Symptoms are maculopapular rash, high fever, cough, and conjunctivitis
• Pneumonia, encephalitis, and Subacute Sclerosing Panencephalitis (SSPE) can occur as complications
• Serology (IgM antibodies) and PCR (viral RNA detection) are used in lab diagnosis
• Treatment involves supportive care such as hydration, fever management, and vitamin A supplements
• Prevention occurs through MMR vaccination and isolation
• Koplik's spots appear before the rash
• There is lifelong immunity after infection or full MMR vaccination
• It is highly contagious

German Measles (Rubella)

• Rubivirus is the causative agent
• Transmission via airborne droplets, direct contact, and mother to fetus
• Symptoms are mild fever and pink maculopapular rash spreading downwards from the face
• Lymphadenopathy occurs
• Congenital Rubella Syndrome (CRS) in newborns can cause deafness, cataracts and heart defects
• Serology (IgM & IgG antibodies) and RT-PCR are used for diagnosis
• Treatment is supportive
• Prenatal immunity screening and the MMR vaccine are preventative measures
• The Rubella rash is milder than measles and disappears faster, but CRS can cause lifelong birth defects.
• Immunity follows infection or full MMR vaccination
• It is highly contagious

Chickenpox (Varicella)

• Varicella-Zoster Virus (VZV), also known as Human herpesvirus 3 is the causative agent
• Transmission through airborne droplets and direct contact with fluid from blisters
• Incubation lasts 10-21 days
• Symptoms include fever and an itchy vesicular rash with a "dew drop on a rose petal" appearance
• Pneumonia, encephalitis, and congenital varicella syndrome (if in pregnancy) can occur
• PCR and Tzanck smear (multinucleated giant cells) are used for lab diagnosis
• Treatment includes acyclovir for severe cases and antihistamines for itching
• Prevention occurs through a live-attenuated varicella vaccine
• The "dew drop on a rose petal" rash is a unique feature
• The virus remains dormant in nerve cells, potentially leading to shingles later
• Varicella vaccine provides long-term, but not lifelong immunity and booster shots may be needed
• It is highly contagious

Shingles (Herpes Zoster)

• The causative agent is Varicella-Zoster Virus (VZV), also known as Human herpesvirus 3
• Transmission occurs through reactivation of the dormant virus in dorsal root ganglia
• A painful, vesicular rash follows a dermatomal pattern, usually unilaterally
• Postherpetic neuralgia (nerve pain even after rash heals) can occur
• Lab diagnosis includes PCR and Tzanck smear
• Treatment includes acyclovir, valacyclovir, and pain management
• The Shingrix vaccine is preventative for older adults
• The rash follows a specific nerve distribution (dermatomal pattern)
• The shingles vaccine provides long-term immunity but may require boosters
• The virus can spread can cause chickenpox in unvaccinated individuals

Hand, Foot, and Mouth Disease (HFMD)

• Coxsackievirus A16 and Enterovirus 71 are the causative agents
• Transmits via the fecal-oral route, respiratory droplets, and direct contact with infected surfaces
• Fever, painful mouth ulcers, vesicular rash on hands, feet, and buttocks are the symptomatic features
• Severe complications include viral meningitis, encephalitis, and myocarditis
• Diagnosis is through PCR and viral culture from throat/stool samples
• Treatment is supportive
• Frequent handwashing and avoiding contact with infected individuals are preventative measures
• Painful mouth ulcers are a unique feature, combined with rash on hands and feet, make it easy to diagnose
• Immunity is not lifelong, and reinfection is possible
• It is highly contagious

Leprosy (Hansen’s Disease)

• Mycobacterium leprae (acid-fast bacterium) is the causative agent
• Transmits via prolonged close contact and respiratory droplets
• Can manifest as:
  • Tuberculoid leprosy, with few skin lesions and nerve damage
  • Lepromatous leprosy, with many lesions, severe nerve destruction, and facial disfigurement
• Laboratory diagnosis includes acid-fast staining, skin biopsy, and PCR
• Treatment involves multi-drug therapy (Dapsone, Rifampin, Clofazimine)
• Prevention via BCG vaccine, early detection, and treatment
• Affects peripheral nerves directly and causes loss of sensation in affected areas
• BCG vaccine provides partial protection, but not lifelong immunity
• It is minimally contagious and only spreads with prolonged close contact

Tetanus

• Clostridium tetani (spore-forming anaerobic bacterium) is the causative agent
• Transmission occurs through deep wounds contaminated with spores (e.g., rusty nails, soil, feces)
• Tetanospasmin toxin is produced, blocking inhibitory neurotransmitters
• Symptoms include muscle spasms, lockjaw (trismus), and opisthotonos, potentially leading to respiratory failure due to diaphragm paralysis
• Laboratory diagnosis is based on clinical symptoms and wound cultures (rare)
• Treatment includes tetanus immunoglobulin (TIG), metronidazole, and muscle relaxants
• Prevention is through the tetanus vaccine (DTaP/Tdap) and wound cleaning
• "Lockjaw" and severe muscle contractions caused by toxin are unique features
• Immunity is not lifelong; boosters are needed every 10 years
• It is non-contagious

Meningitis

• Can be caused by:
  • Bacterial agents like Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae
  • Viral agents such as Enteroviruses, HSV, Arboviruses
  • Fungal agents such as Cryptococcus neoformans, especially in immunocompromised patients
• Respiratory droplets (bacterial & viral), direct contact, and vector-borne (arboviral) transmissions
• Symptoms are fever, stiff neck, headache, photophobia, and altered mental status
• A unique petechial rash is seen in meningococcal meningitis
• Lab diagnosis occurs via lumbar puncture (CSF analysis), Gram stain, PCR, and serology
• Antibiotics (for bacterial), antivirals (for viral), and antifungals (for fungal) are treatment options
• Prevention includes vaccines and hand hygiene
• Nuchal rigidity (stiff neck) and Brudzinski/Kernig signs are classic in bacterial meningitis
• Vaccination provides long-term, but not lifelong immunity
• Bacterial and viral meningitis are contagious

Encephalitis

• Can be caused by:
  • Viral: Herpes simplex virus (HSV), Arboviruses (West Nile, Zika, Japanese encephalitis virus)
  • Bacterial: Listeria monocytogenes
  • Parasitic: Toxoplasma gondii (immunocompromised patients)
• Transmission can occur via mosquito bites (arboviral), respiratory secretions (HSV), and congenital transmission (toxoplasmosis)
• Inflammation of the brain, leading to seizures, fever, confusion, and coma are the main features
• HSV encephalitis can affect temporal lobes, causing memory loss
• Laboratory diagnosis includes CSF analysis, PCR, and MRI
• Treatment includes acyclovir (for HSV), supportive care, and mosquito control
• Vaccines (for Japanese encephalitis) and avoiding mosquito bites are preventative measures
• HSV encephalitis causes necrosis in the temporal lobes
• Immunity Status depends on the virus and some vaccines provide long-term immunity
• It is not contagious, but HSV spreads through saliva contact

Poliomyelitis

• Poliovirus (Enterovirus) is the causative agent
• It presents through fecal-oral route, respiratory droplets
• It can be asymptomatic (90%) or result in mild fever, or paralytic polio (1%), affecting motor neurons and leading to flaccid paralysis
• PCR, stool culture, and serology are laboratory diagnostic procedures
• Treatment invovles supportive care and physiotherapy
• Vaccination (IPV & OPV) is preventative
• Polio mainly affects the spinal cord, causing asymmetric paralysis
• It gives lifelong immunity after full vaccination, and is highly contagious

Rabies

• The causative agent is Rabies virus (Rhabdoviridae)
• It presents through bite/saliva from infected animals (dogs, bats, raccoons)
• It can cause hydrophobia, agitation, paralysis, coma, and death
• Negri bodies in brain tissue and PCR help in diagnosis
• Rabies vaccine & immunoglobulin (post-exposure prophylaxis) offer treatment against the it
• Pre-exposure vaccination and avoiding stray animals can prevent the virus
• There is a nearly 100% fatality rate once symptoms appear
• Full vaccination helps build lifelong immunity
• It only spreads through bites

Diphtheria

• Corynebacterium diphtheriae
• Transmission occurs through respiratory droplets, direct contact with infected wounds, and contaminated objects (fomites)
• Bacteria produces diphtheria toxin, which kills cells in the throat, forming a thick, grayish pseudomembrane
• Symptoms are sore throat, fever, difficulty breathing, thick gray patches in the throat, and swollen neck ("bull neck")
• Airway obstruction, myocarditis (heart inflammation), paralysis, and kidney failure
• Throat swab culture (for C. diphtheriae) and Elek test (to confirm toxin production) are diagnostic measures
• Diphtheria antitoxin, antibiotics (Erythromycin, Penicillin), and supportive care are treatements
• DTaP/Tdap vaccine is a preventative
• Thick pseudomembrane blocks airways
• Vaccine provides long-term immunity, but boosters are required
• Spreads easily through respiratory droplets and is contagious

Pertussis (Whooping Cough)

• The causative agent is Bordetella pertussis
• Common name is Whooping Cough
• Transmission occurs through respiratory droplets and direct contact with infected individuals
• Bacteria attach to the cilia (tiny hairs in the respiratory tract) and produce pertussis toxin, which paralyzes the cilia and causes severe coughing fits
• Symptoms are severe coughing spells (followed by a "whooping" sound), vomiting after coughing, difficulty breathing and fever
• Complications are pneumonia, brain damage, seizures, and death, especially in infants
• Diagnosis is through PCR test (to detect bacterial DNA in a nasal swab) and culture from nasopharyngeal swab
• Its treated with antibiotics (Azithromycin, Clarithromycin, Erythromycin) given early
• DTaP/Tdap vaccine is preventative and requires a booster in adolescence & adulthood
• Coughing fits can last for weeks which is also called "100-day cough"
• Vaccine provides good protection, but immunity wanes over time
• It can be spread via airborne droplets

Tuberculosis (TB)

• Causative agent is Mycobacterium tuberculosis
• Can be transmitted via Airborne through coughing, sneezing and talking that releases TB bacteria into the air
• TB bacteria infect the lungs, forming granulomas (tubercles) in the lung tissue
• It causes chronic cough (sometimes with blood), weight loss, night sweats, fever, and fatigue
• This leads to complications such as Miliary TB (spreads to other organs), TB meningitis, and multi-drug-resistant TB (MDR-TB)
• Diagnosis is through Tuberculin skin test (Mantoux test, PPD test), Chest X-ray (to check for lung granulomas), and Sputum culture
• Antibiotics such as Isoniazid, Rifampin, Ethambutol, and Pyrazinamide are prescribed for 6-9 months
• It can be prevented by BCG vaccine, used in countries with high TB prevalence
• Stays dormant in the body (latent TB) and reactivates later
• BCG vaccine gives partial protection, but it’s not lifelong
• Airborne transmission makes it highly contagious

Influenza (Flu)

• Influenza virus types A, B, C, and D can caused it, Influenza A can cause pandemics
• Airborne droplets, direct contact, and contaminated surfaces
• Virus infects the respiratory tract, damaging lung epithelial cells that causes fever, body aches, sore throat, runny nose, cough, chills, and fatigue are the symptoms
• Complications are Pneumonia, respiratory failure, myocarditis, and secondary bacterial infections
• It can be diagnosed thru Rapid influenza test (detects viral antigens from nasal swabs) and PCR test (confirms specific flu strains)
• A course of Antiviral drugs aids the treatment along with the annual flu vaccination (due to frequent virus mutations) is a good preventative measure
• Flu virus mutates rapidly (antigenic drift & shift), requiring new vaccines yearly
• Vaccine protects for only one flu season and is spread easily through coughing, sneezing, and touching infected surfaces

Pneumonia

• Bacterial causes are Streptococcus pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae
• Viral causes are Influenza virus, Respiratory Syncytial Virus (RSV), and SARS-CoV-2 (COVID-19)
• Fungal cause is Pneumocystis jirovecii (in immunocompromised patients, e.g., HIV/AIDS)
• Pneumonia is transmitted by respiratory droplets, and aspiration of bacteria into lungs
• The infection causes inflammation of the alveoli (air sacs in the lungs), filling them with fluid or pus
• It causes cough with phlegm, fever, chills, chest pain, and shortness of breath
• Complications are Sepsis, lung abscesses, and respiratory failure
• Chest X-ray (to detect lung consolidation/infection), Sputum culture (for bacterial causes), and PCR tests (for viral causes) helps in diagnosis
• The type and cause of the it determines the treatment of bacterial pneumonia (antibiotics) and viral pneumonia (antivirals)
• Pneumonia can be prevented by vaccines, Pneumoccoal vaccine (PCV13, PPSV23), flu vaccine, handwashing, and mask-wearing
• Cause can be multiple such as bacterial, viral, fungal
• Vaccine offers long-term protection, but some may need boosters, and is contagious

Typhoid Fever

• The causative agent is Salmonella enterica serovar Typhi
• It can be transmitted through Fecal-oral route through contaminated food/water or poor hygiene
• Bacteria invade Peyer’s patches (lymphoid tissue in the intestines) and spread to the bloodstream
• Symptoms include prolonged fever, rose-colored rash, abdominal pain, constipation or diarrhea, and weakness. Some complications
• Diagnosis is via Widal test (detects antibodies), Blood culture (for Salmonella Typhi), and Stool & urine culture
• Treatment of the infection can happens through Antibiotics (Ciprofloxacin, Azithromycin, Ceftriaxone)
• Proper hygiene or Typhoid vaccine can prevent it
• Humans are the only reservoir; chronic carriers can spread it
• Vaccine provides partial protection and its spread through contaminated food/water

Bacillary Dysentery

• Shigella spp. is teh causative agent
• It can be transmitted by fecal-oral route and person-to-person contact
• Shigella invades the intestinal lining, inflamming and ulcerating the area by
• With symptoms like bloody diarrhea (dysentery), severe abdominal pain, fever, painful straining; the condition can lead Hemolytic uremic syndrome (HUS) if Shiga toxin is produced
• Infections are diagnosed through stool culture for to detect Shigella and PCR for Shiga toxin genes
• Treatment involves Fluids/electrolyte replacement along with Antibiotics
• Maintaining Handwashing, safe water, and proper sanitation
• Shiga toxin can cause kidney failure (HUS)
• infections don't cause long term immunity and are highly contagious

Cholera

• Vibrio cholerae is the causative agent of the infection which is commonly known by this term
• This disease spreads through Fecal-oral route by contaminated water, seafood, and poor sanitation
• The body produces cholera toxin, which causes massive watery stools, which causes Symptoms such as Severe dehydration, vomiting, muscle cramps, sunken eyes that lead to deadly hypovolemic shock with organ failure, and death
• Its diagnosis is through Stool culture (for V. cholerae) and Rapid dipstick test Oral rehydration therapy (ORT) along withIV fluids can help fight infections and antibiotics (Doxycycline, Azithromycin) are also perscribed by doctors
• Cholera can be avoided by drinking clean water and getting oral vaccination or clean drinking water
• The infection can be deadly because the severe level of the dehydration it brings which calls dieases progression within a shorter length of the period
• Vaccine provides only short-term and is highl;y contagion through contaminations

Gastroenteritis

• This virus has many faces, the most Common agents are:
  • Viral: Rotavirus, Norovirus, Adenovirus
  • Bacterial: Escherichia coli (E. coli), Salmonella, Campylobacter, Clostridium perfringens
  • Parasitic: Giardia lamblia, Cryptosporidium also causes the stomatch condition like influenza Its infection process includes fecal and through contaminated food and water that causes inflammation of the stomach & intestines, leading to vomiting & diarrhea
• It causes Symptoms such as Diarrhea, nausea, vomiting, fever, and stomach cramps and can develop into Complications with dehydration & electrolyte imbalance
• Diagnostic measures include Stool culture and PCR to detect those infections so doctors determine the line of the the treatment The best option to prevent is good food handeling and through hygene practices
• Rotavirus vaccine also helps to prevent the infections and it is spread through direct contact or cantaminated items. It is important to notice, the Gastroenteritis is selflimiting so it does not requires specific long lasting medications and vaccines that protect small babys

Amebiasis

• It has Causative Agent that is Entamoeba histolytica known by its common name, amibiasis, spreads through Fecal-oral route and can be diagnosed via stool examinations and lab work like stool examination can serology
• Its mode of transmission includes contaminated drinking ware like water and food and is very highly contagious
• Its infection cycle beings with cysts and then ends Trophozoites that destruct tissues and causes severe dirrehe, weight loss and fevers. The result can be damaging leading to perfitions and livers
• It needs both antibiotics to prevent its infection and cleaning procedures like hand washing and water boiliongs to stop contamination spread or direct contact and infection is possible

Heptaitis

• The liver infection is caused by 3 main agents that each agent exhibits their transmission path and symptoms. The best part is there are vacine for A and B infections that can helps its prevention and spread by avoiding infections and spreading thier infection
• A class: HAV are the main agent, spread through contamination and its cure is through treating the symptoms, which creates good long lasting antibodies leading to immunity
• Agent is HBV, C - its transmission is through bodily fluid which creates long term issue leading to liver failures and can be deadl
• C infections are now curable though C meds and early interventions are needed

Enterobiasis

• Is caused by Enterobius vermicularis, also known as pinworm, that spreads through Fecal-oral route where the eggs are injessted and adult worms create intensite tissue inflammations and anal itch, along with sleep distubences and imflammation
• This infection can be detected through samples and is treated with Albinezadole and can be easily solved with simple hygeine prtactices in schools and and household practices

Ascariasis

• Is a condtion where causitive agent that are spreaded thru
• Fecal-Oral route are taken into bodies through contiminated drink or ware, then Larvae create irritation and infection by affecting intestines and then lungs, causing Cogh wheezing with malnutrition
• All infection are diagnosised at stool, is treatable with Albendazole, with hygeine and prevention programs from spreading infections again

Strongyloidiasis

• Is one form of parasites disease that causitive agents are S. stercoralis and is spreaded thru direct skin contact. Parasited creatses infections where skin turns red inflamed and causes, coughs with diharrea but is not life threating if treated prompty
• It is diagnosed in stool samplings. To treat its infections all that are needed is hygeine and Ivermectin to kill infections

Trichuriasis

• Its cause is by Trichuris that spreads with Fecal route contaminations that result in long term inflammining infections that causes heavy blood loss
• It is diagnoised in stool and treated wit hMebendezol, all it requires is prevention through clean ware

Ancylostomiasis

• It coused the infection to hook worm, ancylostoma, spreads by walking by bearfood to contact with fecal contents
• This leads into infection causing skin irratiation , abdominal pain followed by internal bleeding It can be treatable but if untreated can lead too fatigue with anemia and infections needs to be diagnosed immediately by stool samplings to prevent infection with Antibiotics