Zoonosis Flashcards
What is zoonosis?
a disease involving at least 2 hosts (human and vertebrate animal species) and a pathogen
How many pathogens infecting humans are zoonotic? What are the top 5 zoonotic pathogen species?
60%
- helminths
- viruses
- protozoa
- bacteria
- fungi
What is the main source of zoonosis? Why?
domestic animals —> genetically more similar to mammals
What mammals transmit the most zoonotic pathogens?
- rodents
- carnivores
- ungulates
- primates
- bats
- shrews and moles
What are the top 8 etiological agents of zoonosis?
- prion
- virus
- bacteria
- fungi
- protozoa
- cestodes
- trematodes
- nematodes
In what 3 ways can zoonosis be classified based on direction of transmission?
- ANTHROPOZOONOSES - animals are the main host; animal-to-human (rabies, influenza, Rift Valley fever, anthrax, brucella, leptospirosis, plague, Lyme, tularemia, psittacosis, hydatidosis)
- ZOOANTHROPOZONOSES - humans are main host; human-to-animal (amoeba, diphtheria, tuberculosis)
- AMPHIXENOSES - migrate in either direction between animal and humans equally (salmonella, staphylococcus, streptococcus, E. coli)
In what 4 ways can zoonosis be classified based on the number of host species (maintenance cycles) are required for transmission?
- ORTHOZOONOSIS (direct) - 1 host species, directly from infected to susceptible host
- CYCLOZOONOSIS (indirect) - 2 host species, including an intermediate host —> taeniasis, echnococcosis
- METAZOONOSIS - 1 host vertebrate + 1 invertebrate —> vector-borne diseases
- SAPROZOONOSIS - 1 host species + abiotic environment, like soil, water, or garbage —> nematodes, fungi
What 4 zoonotic pathogens have caused pandemic diseases?
- Yersinia pestis - plague (Black Death)
- Vibrio cholerae
- Influenza A
- SARS-CoV, MERS-CoV - Coronavirus
What kind of pathogens are on List A in CDC-recognized bioterrorism agents? What 5 are part of the list?
easily disseminate and cause high morbidity and mortality, public panic, social disruption, etc.
- anthrax
- plague
- tularemia
- botulism toxin
- viral hemorrhagic fever (have not been used by terrorists) —> Ebola/Marburg, Crimean-Congo virus
Most bioterrorism agents target what 3 body systems?
- respiratory system
- nervous system
- cardiovascular system
What 10 zoonotic bioterrorism agents are part of the CDC List B?
- Burkholderia pseudomallei - meliondosis
- Burkholderia mallei - glanders
- Brucella spp. - brucellosis
- Chlamydia psittaci - psittacosis
- Coxiella burnetii - Q fever
- Rickettsia prowazekii - typhus
- E/WEE - virual encephalitis
- TOXINS - ricin, Staph. aureus enterotoxin, Clostridium perrfingens
- FOOD - salmonella, shigella, E. coli O157
- WATER - V. cholerae, cryptosporidium
CDC lists of zoonotic pathogens:
Why are neglected zoonoses important?
diseases of the poor society - many become emerging/re-emerging diseases, so they hold priority of control in a one health approach
- 27 total neglected diseases with 8 of one health priority
What are the top 8 zoonoses with one health significance of most concern in the USA?
- rabies
- zoonotic influenza
- emerging coronaviruses (SARS, MERS)
- WNV
- salmonellosis
- brucellosis
- plague
- Lyme
What 3 agencies take part in the one health initiative?
- CDC
- USDA
- DOI
Where do fish pick up zoonotic pathogens?
aquatic environment contaminated by sewages from agriculture, human/animal excrements, and wild animals
Fish-borne zoonotic bacterial diseases:
How are humans affected by Vibrio vulnificus infection? What is the main source?
necrotic fasciitis
eels
Who are at highest risk for Erysipelothrix rhusiopathiae infection? What is characteristic of this infection?
fish handlers —> purple, swollen, painful, and hardened rash (erysipeloid) that does NOT produce pus
How are humans typically affected by Mycobacterium marinum?
tender nodules —> swimmer granuloma
What zoonotic cestode is commonly spread by fish? Nematode?
Diphyllobothrium
Anisakis
What are the 3 possible hosts of zoonotic fish-borne trematodes? What 2 cause liver cancer?
- primary snail host
- secondary fish host
- human, dog, or bird DH
Opisthorchis and Clonorchis