Infectology 2026 Exam 1/3

MOST IMPORTANT ONE!!!

List and brief description of the periods of pathogenesis of infectious diseases

1 Incubation period:
entry of pathogen to first symptoms. Multiplies and spreads

2 Prodromal period:
Non specific symtoms: fever, malaise, fatigue, headache

3 Clinical manifestations
Full disease picture with specific symptoms, highest pathogen load

4 Decline
Decrease of symptoms caused by immuneresponce or treatment

convalescence/Recovery
symptoms disappear, tissue repear

List and describe the routes of transmission of infectious diseases, give at least one example for each

Contact: direct/indirect, Gonorrhea

Dropplet: Large respiratory droplets, Influenza

airborne: Long distance in air, Tuberculosis

Fecal-oral: Ingeston of contaminated food/water, cholera

Vector borne: by arthropods (Mosquitoes, ticks), Malaria, lyme disease

Parentreral (blood bone): Blood, HIV

Vertical: Mother→child: syphilis

The differences between the concepts of "infection" and "infectious disease" and the reasons contributing to the development of an infectious disease.

Infection: Entry, survival, and multiplication of a microorganism in the body,
Can be asymptomatic and cause no tissue damage

Infectious disease: infection + symptoms & tissue damage

Reasons contributing to the development of an infectious disease:
Pathogen factor: dose, resistance
Host factor: weak immunity, age, diseases
Enviormental factors: Poor hygine/sanitation
Host pathogen interaction imbalance: If pathogen overcomes immune responce

Diagnostic principles of infectious diseases and verifycation of specific infections.

Clinical assesment: Histoy, examination
Laboratory testing: Culture, seology, PCR/NAAT, antigen detection
Histopahology: Examine biopsy
imaging: Xray, CT, MRI

Verification of Specific Infections: 
Viral: PCR, Serology
Bacterial: Gram staining, PCR
Fungal/parasitic: culture, PCR, microscopy
History, symptoms, laboratory confirmation

Principles of infectious disease treatment. Indications for serum, immunoglobulin, and antibiotic therapy.

Principles of Infectious Disease Treatment:

Identification of the Pathogen:

Assessment of Severity:

Start with broad-spectrum therapy then switch to a narrower

Supportive Therapy:

Source Control: Draining abscesses or removing infected medical devices. 

Indications for Serum/Antitoxin Therapy: 

neutralizing bacterial toxins or venoms. 

-Provides passive immunity with pre-formed antibodies. 

Examples: Diphtheria antitoxin, tetanus antitoxin, botulinum antitoxin, snake antivenom. 

Indications for Immunoglobulin Therapy

Post-exposure Prophylaxis: For immediate protection after exposure

Immunodeficiency Disorders:

Autoimmune and Inflammatory Disorders:

Treatment of Severe Infections

Indications for Antibiotic Therapy: 

Bacterial Infections:

Empiric Therapy: I

Targeted Therapy:

Influenza - incubation period, clinical presentation, and complications.

incubation period,
1-4 days

clinical presentation,
Sudden fever
Myalgia (muscle pain)
Headache
cough
sore throat
Rhinits

complications
Otitis, sinusitis, bronchitis
Viral/bacterial pneumonia

Influenza – principles of treatment and prevention (non-specific and specific).

principles of treatment
Supportive: selflimiting,hydration,rest, analgesics,
Avtiviral:osteltamivir,zanamivir

prevention (non-specific and specific).
Annual influenza vaccine
Avtiviral:osteltamivir,zanamivir can be used as prevention
non specific: hand hygine, dont cough out, masks, avoid contaminated people/surfaces, isolation

Parainfluenza - incubation period, clinical presentation, and complications.

incubation period,
2-6 days

clinical presentation,
common cold
cough, stridor, hoarsness, fever, dyspnea,

complications
Otitis, sinusitis, bronchitis
Viral/bacterial pneumonia

Diphtheria – clinical presentation and principles of treatment.

Clinical presentation
2-5 days
Fever, throat pain, malaise, dysphagia, lymphadenopathy
gray white pseudomembrane on tonsils/pharynx
Bull neck

principles of treatment.
isolation
Diphtheria antitoxin DAT
Antibiotics: Penicillin G, erythromycin
airway mangement
IV fluids
Cardiac monitoring

Legionellosis – clinical presentation and principles of treatment.

clinical presentation
2-10 days
Flu-like symptoms: fever, myalgia, heacache, Cough, dyspnea,
Pneumonia, diarrhea, confusion,

principles of treatment.
Antibiotics: Ciprofloxacin azithromycin and doxycycline
supportive: Oxygen, IV fluids,

Shigellosis: clinical manifestations, principles of diagnosis and treatment, prevention.

clinical manifestations,
1-7 days
watery diarrhea
fever, abdominal cramps
tenemus (train to defecate)
Bloody mucoid stool

principles of diagnosis
Stool culture
PCR

treatment,
Supportive: rehydration, electrolyte
Antibiotics: Ciprofloxacin azithromycin and doxycycline

prevention.
Hand/food washing
disposal of sewage
avoid swallowing outside water

Botulismus: clinical manifestations, principles of diagnosis and treatment, prevention.

clinical manifestations
1 day incubation, systemic paralysis, double vision, slurred speech, systemic muscle weakness

principles of diagnosis
Symptom: acute paralysis, no fever
Serum/culture: Botulinum toxin in stool/food/gastric
Mouse bioassay
ELISA

treatment,
Supportive: ventilation, circulation support
Botulinum antitoxin

prevention.
thorough cooking/canning
Clean
separate raw and cooded food
Safe water

Cholera: epidemiology, clinical manifestations, principles of diagnosis and treatment, prevention.

Epidemiology,
Fecal oral, human reservoir

Clinical Manifestations,
1-5 days incubation
Watery diarrhea, mucus flakes → rice water
Fluid loss, vomiting, dehydration

Principles of Diagnosis
severe Dehydration
stool microscopy
Culture
rapid diagnostic tests
PCR

Treatment,
rehydration
Antibiotics: Ciprofloxacin azithromycin and doxycycline

Prevention.
safe food/water
sweage disposal
hand hygine
vaccine
educaiton

Typhoid fever: clinical manifestations, principles of diagnosis and treatment, prevention.

salmonella infection

Clinical Manifestations,
1-2 weeks incubation
Gradual increasing: Fever, heacache, malaise, anorexia, abdominal pain,
Constipation/diarrhea
→ rash/rose spots on trunk, hepatosplenomegaly,

Principles of Diagnosis
Urine/stool/Blood/bone marrow culture
Anemia, neutropenia, thrombocytopenia

Treatment,
Rehydration, electrolytes,
antibiotics: Ciprofloxacin azithromycin and doxycycline

Prevention.
vaccine
safe water/food
hand hygine
treat carriers

Campylobacteriosis and Yersiniosis: clinical manifestations, principles of diagnosis and treatment, prevention.

Clinical Manifestations,
2-5 day invubation
fever, abdominal pain, watery diarrhea, nauease

Principles of Diagnosis
Stool culture
PCR
Yersiniosis: blood culture, throat swap, serology

Treatment,
Ciprofloxacin azithromycin and doxycycline 
Self limiting
supportive: rehydration, antimotility and nausea drugs

Prevention:
hand hygine, food safety
Campylobacteriosis:proper cooking poultry, Avoid raw milk
Yersiniosis:Avoid undercooked pork

Diarrheagenic E. coli subtypes: clinical manifestations, principles of diagnosis and treatment, prevention.

Types:
EHEC, ETEC, EPEC; EIEC, DAEC (T,I,P,H)

clinical manifestations
Abdominal pain
waterry non blood Diarrhea (traveler’s diarrhea)
loss of papetite
nausea/vomiting
Fever
Fatiugue
swollen abdomen

principles of diagnosis
PCR, Detect enterotoxins/shigatoxins as can not itself be distinfused from normal microflora
Stool culture

treatment,
Rehydration,
antibiotics: Ciprofloxacin azithromycin and doxycycline 

prevention.
Hand hygine
Food water safety
sanitation

Traveler's diarrhea – etiology, clinical manifestations, principles of diagnosis and treatment, prevention.

Etiology
acute infectious diarrhea occurring in people traveling to resource-limited regions. 

Bacteria E.coli
Norovirus
Protozoa

clinical manifestations
Abdominal pain
waterry non blood Diarrhea (traveler’s diarrhea)
loss of papetite
nausea/vomiting
Fever
Fatiugue
swollen abdomen

principles of diagnosis
Clinical
PCR, Detect enterotoxins/shigatoxins as can not itself be distinfused from normal microflora
Stool culture

treatment,
Self limiting- Rehydration, supportive
if needed: Ciprofloxacin azithromycin and doxycycline

prevention.
Hand hygine
Food water safety
sanitation

Parasitic intestinal infections with the clinical picture of gastroenterocolitis: amebiasis, giardiasis, cryptosporidiosis - clinical picture, diagnostic and treatment principles, prevention.

amebiasis,
clinical picture: aysmptomatic, bloody diarrhea, liver abscess
diagnostic: Stool microscopy (cysts/trophozoites), ELISA, PCR
treatment: Metronidazole → luminal agent, liver drainage

giardiasis,
clinical picture: 1-2w incubation, watery diarrhea, foul smelling greasy stool
diagnostic:Stool microscopy (cysts/trophozoites), ELISA, PCR
treatment: Metronidazole

cryptosporidiosis
clinical picture: watery diarrhea
diagnostic: ELISA,PCR
treatment: self limiting unless immunosupressed/HIV,

General symptoms: low fever, weight loss, nausea, cramps
prevention:
Safe drinking water/food
Hadwash,

The most common blood borne diseases: VHB, VHC, HIV, epidemiology in the world and in Latvia, risk groups, possible routes of transmission.

VHB

Epidemiology: 7% world, 2-3%Latvia
risk groups: Healthcare workers, drug users, Homosexuals
Trasmition risk: Bloodborne, body fluids/sex, mother to child

HCV
Epidemiology: 3% world, 2% latvia
risk groups: Healthcare workers, drug users,
Trasmition risk: Bloodborne, mother to child

HIV
Epidemiology:1% world,
risk groups: Healthcare workers, drug users, Homosexuals,
Trasmition risk:Bloodborne, body fluids/sex, mother to child

Viral hepatitis B - epidemiology, clinical symptoms and outcomes.

epidemiology, High prevelance in afrika and poor countries, low in europe
7% world, 2-3%Latvia

clinical symptoms
Acute infection: non specific symptoms, asymptomatic
Chronic infection: long time asymptomatic, Liver damage, cirrhosis, carcinoma

outcomes.
Most adults clear the infection spontaneously
Cirrhosis, liver failure, death

Classification and diversity of parasitic diseases on the world map.

Classification:
Size (micro or macroparasites)
Host dependecncy to survive (obligate, faculative)
Live on or in host: (endoparasites, ectoparasites)

(Afro prototype helmets)

Arthorpods: hard shell

Protozoa: single cell

Helminths: multicellular worms

Design of diseases caused by protozoa - the most common pathogens and a brief description of their clinical profile.

• Amebiasis (Entamoeba histolytica)
  → bloody diarrhea, abdominal pain, liver abscess

• Giardiasis (Giardia lamblia)
  → greasy foul-smelling diarrhea, bloating, malabsorption

• Malaria (Plasmodium spp.)
  → cyclic fever, chills, anemia, splenomegaly

• Toxoplasmosis (Toxoplasma gondii)
  → usually mild; severe CNS disease in immunocompromised and congenital infection

  ---

• Leishmaniasis (Leishmania spp.)
  → cutaneous ulcers or visceral disease with fever and hepatosplenomegaly

• African Trypanosomiasis (Trypanosoma brucei)
  → fever, lymphadenopathy, daytime sleepiness, neurologic symptoms

• Chagas Disease (Trypanosoma cruzi)
  → cardiomyopathy, arrhythmias, megacolon, megaesophagus

• Cryptosporidiosis (Cryptosporidium spp.)
  → watery diarrhea, severe in AIDS patients

Malaria - pathogenesis, clinical manifestations, diagnosis, treatment and prevention.

pathogenesis,
Transmission of plasmodium sporozoites by mosquito bite, traveling thuogh bloodstream to liver

clinical manifestations,
fever, headace, chills
fatuige, impared consciousness, convulsions, jaundice

diagnosis,
microscopy of blood smear
Symptoms
Rapid diagnostic test
Serology: ELISA

treatment
Artemisinin, chloroquine, primaquine

prevention.
Avoid mosquitos, nets, repellent
medication

Echinococcosis - clinical forms, diagnosis and treatment principles and prevention options.

clinical forms,
Cystic Echinococcosis (CE, Echinococcus granulosus): Large fluid filled cysts in liver/lungs
Alveolar Echinococosis (AE, Echinococcus multilocularis): Acts like a malignant tumor in liver

diagnosis
US/CT/MRI: cysts/lesions
Serology: ELISA

treatment principles
Albendazole/Antiparasytics
PAIR
puncture/aspiration
surgery

prevention options
Deworming of dogs
hygine
safe food
safe disposal of animal waste
Education

Name the most common human helminthiasis and describe the routes of transmission, mechanisms of pathogenesis and main clinical signs.

Soil transmitted helminths

Ascariasis:
Fecal-Oral
Intestine→blood→lungs→swallowed→ small intestine
Cough, feves, abdominal pain, malnutition, obstruction

Trichuriasis:
Fecal-oral
Worms invade colonic mucosa causing inflammation
Abdominal pain, diarrhea, infection, anemia

Hookworm:
Larvae in soil penetrate skin
attach to small intestine wall → feed on blood
itch at penetration site, cough, iron deficiency/anemia, fatuige

Pneumonia caused by Chlamydia psittacci: reservoir of infection, risk factors, clinical manifestations, principles of diagnosis and treatment.

reservoir of infection,
Bird (parrots, chickens) droppings

risk factors,
Close contact with birds (work)
Immunocompromised/elder

clinical manifestations,
1-2w incubation
Sudden high fever, headache, cough, dyspnea

principles of diagnosis
Serology ELISA, igG,IgM
PCR
Hisory of birds

treatment.
Ciprofloxacin azithromycin and doxycycline 

Toxocariasis: etiology, transmission, clinical manifestations, diagnosis, treatment and prevention.

etiology,

From dogs (toxocara canis) or cats (toxocara cati)

transmission,
fecal-Oral accidental

clinical manifestations,

Fever, cough, abdominal pain, lymphadenopathy
Liver, lungs, eye, → vision loss, hepatomegaly

diagnosis,
Serology ELISA
History of pets

treatment
Albendazole/Antiparasytics

prevention options
Deworming of pets
hygine
safe food
safe disposal of animal waste
Education

Infections caused by non-tuberculous mycobacteria: etiology, risk factors, clinical syndromes, diagnosis.

etiology,
Myobacterial species other then tuberculosis
enviormental in water and soil. (M avium complex, M.Kansasii)

risk factors,
Lung diseases: COPD, cystic fibrosis
Immunosupression: HIV, maligancy
Age/gender: old woman

clinical syndromes,
Pulmonary disease
Cervical lymphadeitis
Skin and soft tissue infection
Disseminated disease

diagnosis.
Biopsy
Microscopy
Culture
PCR

Cat scratch disease: etiology, clinical manifestations, diagnosis and treatment.

etiology,
Bartonella henselae Bacterial infection from cat scratches

clinical manifestations,
Leason
Lymphadenopathy
Systemic: fever, malaise, heachace, fatuige

diagnosis
History of cats
Serology ELISA
PCR: aspirate/Biopsy

treatment
suportive and self limiting
(antibiotics )

Toxoplasmosis: reservoir of infection, transmission, risk factors, clinical manifestations, principles of diagnosis and treatment.

reservoir of infection,
Definitive: Cats/felines
Intermediate: mammals, birds, Humans

transmission,
fecal-oral
undercooked infected meat

risk factors,
Eating raw meat
Contact with cat litter
poor hand/food hygine
Immunosupression

clinical manifestations,
Immunocompetent: flue like
Congenital: miscarriage
Immunocompromised: HIV

principles of diagnosis
Serology: ELISA
PCR
CT/MRI (CNS involvmetn)

treatment.
not needed if healthy
if pregant: spiramycin to not innfect fetus
Immunocompromised/infected fetus: pyrimethamine + sulfadiazine