Lecture 16 & 17 Flashcards
Reservoir
the pathogen is viable (growth, reproduction, and transmission)
- animate and inanimate
Vector
the pathogen is transmitted (direct or indirect)
- animate
soil-borne diseases
- fungal and bacterial pathogens
- cannot be eliminated
What are 3 animal-transmitted diseases?
Psittacosis (bacterial), rabies and hantavirus (viral)
What pathogen is rabies?
Rhabdovirus
- negative sense, single stranded RNA
- small genome
What are the reservoirs of rabies?
domestic animals and wild animals
How is rabies transmitted?
infected animal bite
What is the epidemiology and pathology of rabies?
- virus in animal saliva
- infects human host via animal bites
- proliferates in the brain
What are the symptoms of rabies?
- excitation, anxiety, and pupil dilation
- excessive salivation
- hydrophobia
How is rabies diagnosed?
- laboratory analyses (look for negri bodies– post mortem)
- wild vs. domestic animals
How is rabies treated?
- Passive immunization (anti-rabies virus antibodies)
- Active immunization (rabies virus vaccine)
- Passive + Active therapy nearly 100% effective
How is rabies prevented?
Through immunization of high risk individuals, domestic animals, and wild animals
What is the reservoir and transmission Hantavirus?
rodents (mice, rats, voles) and infected animal feces
What is the epidemiology and pathology of hantavirus?
- inhalation of fecal dust from infected animals
- proliferates in the human body
- Hantavirus Pulmonary Syndrome and Hemorrhagic fever with renal syndrome
what is the diagnosis of Hantavirus Pulmonary Syndrome?
- symptoms: fever, muscle pain, thrombocytopenia (decrease in platelets), leukocytosis (increase in leukocytes)
- lab tests: virus cultures (dangerous), ELISA, PCR
Is there any treatment or vaccines for Hantavirus Pulmonary Syndrome?
No
Viral hemorrhagic fever (VHF)
- biosafety level 4 viral pathogens
– Hantaviruses
– Filoviruses (ebola)
What is the pathogen and reservoir for psittacosis?
- Chlamydia psittaci
- Birds (parrots and poultry)
How is psittacosis transmitted?
- infected animal feces
- infected saliva
What is the epidemiology and pathology of psittacosis?
- rare but underestimated disease that has occasional outbreaks
- inhalation of fecal dust from pets or poultry
- lung infection (pneumonia) in severe cases
How is psittacosis diagnosed?
symptoms: fever, headache, dry cough (many others)
- all similar to other respiratory infections
Molecular PCR tests
How is psittacosis treated and prevented?
- antibiotics (tretracycline)
- no vaccine available
- awareness: safe bird and cage care
What are the arthropod-transmitted diseases?
- lyme disease and plague (bacterial)
- west nile (viral)
- malaria and trypanosomiasis (protist)
What is the pathogen, reservoir, and vector of lyme disease?
- borrelia borgdorferi (bacteria)
- mammals (rodents)
- Ixodes scapularis (ticks)
What is the epidemiology and pathology of Lyme disease?
- untreated, the disease reaches the CNS
- no toxins or virulence factors known
What are the symptoms of Lyme disease?
- Acute stage: rash, head, backache, chills, and fatigue
- Chronic stage: arthritis, and neurological + heart damage
How is Lyme disease diagnosed?
symptoms+ tick exposure + rash
-ELISA, western blot, PCR assays
What is the treatment and prevention for Lyme disease?
- antibiotics (acute vs. chronic stage)
- vaccine (human +animal)
- reduce exposure to ticks and properly remove them
What is the pathogen, reservoir, and vector of the plague?
- Yersinia pestis (bacterium)
- rodents
- fleas
What is the epidemiology and pathology of the plague?
- lymph node swelling (buboes)
- bloodstream (septicemia)
What are the four types of plague?
- Sylvatic
- Bubonic
- Pneumonic
- Septicemic
Sylvatic plague
- in flea vector on rats
Bubonic plague
- in flea vector on humans
- transmitted
Pneumonic plague
- direct inhalation
- acute infection in lungs leads to transmission to other people
Septicemic plague
- no buboes
- no characteristics signs
- die very quickly
What is the treatment for the plague?
*different based on type
- bubonic: antibiotics (early stage) reduce mortality to 1-5%
- pneumonic: rapid disease progression, mortality 90%
- septicemic: death occurs before diagnosis
How is the plague prevented?
- control animal reservoirs, vectors and human contact
- plague infected animals must be destroyed
What is the pathogen, reservoir, and vector of malaria?
- plasmodium spp. (protist)
- humans + mosquitoes
- Anopheles spp. (mosquitoes)
What is the plasmodium life cycle?
- Fertilization occurs in mosquito host
- Sporozoites transferred from mosquito to human host
- Merozoite form in liver
- Gametocytes form in blood and then transferred to mosquitos
What are the symptoms and diagnosis of malaria?
- chills + fever, headaches, anemia, and enlarged spleen
- D: infected RBCs and PCR tests can determine species
What is the treatment for malaria?
- Chloroquine (kills merozoites and inside RBCs)
- Primaquine (kills merozoites, sporozoites + gametes and outside blood cells)
What are the ways to prevent malaria?
- high risk areas, ppl get doses of chloroquine
- disrupt pathogen life cycle
- no effective vaccine at present
What is the pathogen, reservoir, and vector of trypanosomiasis?
- Trypanosoma (protist)
- Humans and mammals
- Tsetse fly (sleeping sickness), triatomines (Chagas)
What is the epidemiology and pathology of trypanosomiasis?
Chagas
- acute + chronic
- in central and South America
Sleeping sickness
- stage 1 +2
- Sub-Saharan Africa
What is the acute v chronic symptoms of chagas?
- acute: swelling at site of inoculation and infection often mild or asymptomatic
- weeks to months following infection
- chronic: 70-80% lifelong infection (no symptoms and 20-30% life threatening heart/circulation problems
*months to years following infection
What is the stage 1 + 2 symptoms of sleeping sickness?
- stage 1: protists multiple in tissue & blood and fever, headache, joint pains
- stage 2: protists cross blood-brain barrier & behavior changes, confusion, poor coordination, sleep cycle disruption
How is trypanosomiasis diagnosed and treated?
- Lab analyses (microscopy)
- Antibiotics
What prevention methods for trypanosomiasis?
- no vaccines
- educate people
- avoid arthropod vectors
What is the pathogen, reservoir, and vector of West Nile Virus?
- West Nile Virus (flavivirus)
- Birds
- Mosquitos
What is the epidemiology and pathology of West Nile Virus?
- Invades nervous system
- Viremia
- High bird mortality
- Survivors immune
- Virus replicates in vector
What are the symptoms and diagnosis of West Nile Virus?
- West Nile fever (20%): headache, nausea, muscle pain
- Neurological diseases (1%)
- 80% asymptomatic
- ELISA test for antibodies
What is the treatment and prevention for WNV?
- No anti-viral drugs
- No effective human vaccine (there is veterinary vaccine)
- supportive care
- limit exposure to mosquitos and destroy habitat
What is the epidemiology and pathology of fungal diseases?
- allergic reactions (hypersensitivity to fungal exposure)
- mycotoxins (exotoxins produced by fungi)
- mycoses (fungal growth on or in the human body)
What does ergotism or claviceps purpurea cause?
- produces the mycotoxin ergotamine
- causes hallucinations and vasoconstriction
- historical significance
Mycoses have effects superficially, subcutaneously, and systemically. What are those effects?
- Superficial: infection on surface layers and spread by contact
- Subcutaneous: infect deeper skin layers and spread by wound infection
- Systemic: infection of internal organs and primary vs. secondary infections
What are the treatment and prevention for mycoses?
- antifungal compounds (topical+oral)
- side effects common
- reduce exposure
What is the pathogen, reservoir, and transmission for tetanus?
- Clostridium tetani
- soil
- contaminated wounds
What is the epidemiology and pathology of tetanus?
- germination of endospores
- production of exotoxin, tetanus toxin
What is the diagnosis for tetanus?
- exposure risk
- clinical symptoms
- toxin identification (rare)
What is the treatment for tetanus?
- antitoxin: neutralize toxin
- antibiotics: prevent addition toxin production
- symptoms irreversible once present
What is the prevention for tetanus?
- vaccine
- “boost” shots
- high-risk age group (25-59 yr olds)
What is the pathogen, soil, transmission for anthrax?
- bacillus anthracis
- soil
- wounds or skin lesions
What is the epidemiology and pathology for anthrax?
- germination of endospores
- virulence factors: toxins + protein capsule
What is the diagnosis for anthrax?
- painless, black lesion (cutaneous)
- blood diarrhea, pain (intestinal)
- toxemia, septic shock (inhalation)
What is the treatment + prevention for antrhax?
- antibiotics
- livestock + human vaccine
