Chapter 5 Flashcards
Zoonosis
An infectious or infectious diseases transmissible under natural conditions from vertebrate animals to humans
Methods for transmission of zoonoses (4 ways)
- Contact with the skin
- A bite or scratch from an animal
- Direct inhalation or ingestion
- Bite of an arthropod (insect, spider, crustacean) vector
Definition of vector
An insect or any living carrier that transports an infectious agent from an infected individual to a susceptible individual, food, or immediate surroundings
Two types of vectors
- Various species of rodents
- Arthropods
Vector of epidemic typhus
Body louse
Vector of Tualaremia
Horse fly
Malaria found in how many countries?
More than 100
What percentage of world’s population at risk for malaria?
40%
Annual death toll for malaria is…
more than 1 million persons
Agent of malaria
Plasmodium parasite
Vector of malaria
Anopheles mosquito
Explain transmission of malaria.
Complex life cycle of mosquitos and human hosts with human liver and blood stages
Most deadly agent of malaria
Plasmodium falciparum
Symptoms of malaria
Spleen enlargement, flu-like fever, muscular fatigue, chills/sweating, dry cough
Estimated global economic cost of malaria
$12 billion
4 forms of mosquito control measures:
- Anti larval measures
- Anti adult measures
- Protection against mosquito bites
- Legislative control
Sickle cell disease
Inherited disease of red blood cells that affects hemoglobin and interrupts blood flow by blocking small blood vessels
Ways to treat sickle cell
- Fluids
- Antibiotics
Hand Foot Syndrome - Dactylitis
Sickle cells cause painful swelling of hands and feet
How do people develop sickle cell disease?
If they inherit two faulty copies of gene for hemoglobin, meaning they confer some resistance to malaria
Agent of Leishmaniasis
Leishmania parasite
Vector of Leishmaniasis
Sandfly who transmits by biting host
How many infected by leishmaniasis every year
700k to 1.2 million
Leishmaniasis is endemic in how many countries?
82 tropical countries
2 forms of leishmaniasis
- Cutaneous - causes one or more sores on skin, swollen glands near sores
- Visceral - causes fever, weight loss, spleen/liver enlargement, abnormal blood tests, low blood counts
4 environmental factors associated with increase in leishmaniasis
- Movement of human population into endemic areas
- Increasing urbanization
- Extension of agricultural projects into endemic areas
- Climate change
Agent of plague
Yersinia pestis
Vector of plague
Flea which bites rodents who harbor it
Treatment for plague
Antibiotics such as doxycycline and ciprofloxacin, oxygen, intravenous fluids, respiratory support
Most common vector-borne disease in the United States
Lyme disease
Agent of lyme disease
Bacteria
Vector of lyme disease
Black-legged ticks
Lyme disease symptoms
Characteristic skin rash which looks like a bull’s eye, fatigue, chills/fever, headache, muscle and joint pain, swollen lymph nodes
Treatment for lyme disease
Antibiotics
Agent of RMSF
Bacteria
Vector of RMSF
Tick
RMSF case fatality rate among untreated patients
Up to 25%
Treatment of RMSF
Early treatment with antibiotic doxycycline
Symptoms of RMSF
Fever, rash, vomiting, etc.
Lyme disease host
Deer
A febrile disease
Disease resulting in fever
