ENVS 285 midterm

what is a zoonoses?

transmission of infectious agent to humans from animal reservoir without establishment of permanent new life cycle in humans (still requires animals)

what is symbiosis?

Close association between two different species (has many types: can be beneficial, one sided, negative, etc)

what is the difference between wildlife, feral, domestic, and captive animals?

wildlife- w/o human care, not a genotype selected by humans

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feral- w/o human care, genotype selected by humans

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domestic- w/ human care, genotype selected by humans

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captive- w/ human care, not a genotype selected by humans

what are parasites?

Organism that benefits at the expense of its host in a close association (takes meals, do not kill host)

what does endemic mean?

it is a common infectious agent in a certain population, low incidence but regularly present

what does epidemic mean?

uncommon in a certain population, high incidence disease affecting many within an area at one time

what is a disease?

**Any impairment interfering with or modifying performance of normal functions**, including responses to environmental factors like nutrition, toxicants, infectious agents, congenital effects (more than just pathogens; injury counts too)

\*\*what is a pathogen?

disease causing agent

\*\*what is a direct life cycle?

Parasite passes through direct contact of host → host

what is an indirect life cycle?

Parasite transmits using a vector and/or intermediate host to get to the next, host → vector → host

what is a definitive host?

Host where parasite reproduces sexually

what is an intermediate host?

Host where parasite does not reproduce sexually (asexual reproduction and/or development)

what is incidence?

reports # of new infections

(# of NEWLY infected/# at risk from starting point)

what is prevalence?

reports total infections in population

(# of animals infected/all # at risk in population) \* 100

what is infestation?

presence of ectoparasites on a host

\*\*what is intensity?

\# of parasites of a particular species in/on a single animal

what is mortality?

Death of host (rate of death per infected)

what is morbidity?

Condition of having illness, weakness, or other disability (rate of harm per infected)

\*\*what is virulence?

Negative impact pathogen on host (includes mortality, morbidity)

what is density-dependence?

Risk of disease varies with density (ex: aerosols, physical contact, etc)

what is density-independence?

Risk of disease does not vary with density (ex: sexual contact, etc)

\*\*IgG is what? And why is it useful?

IgG is one of the five major immunoglobulin classes for mammals

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it is a type of antibody that is produced by white blood cells

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it is part of humoral immunity in the acquired immune system

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it is the more abundant antibody in the mammalian circulatory system

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determines history of infection to a pathogen

how can we classify bacteria zonnoses?

if they are gram negative/positive

is a virus alive?

no

can a virus replicate outside a host?

no

\*\*what does obligate mean?

Incapable of replication & assembly without using host cellular processes

compared to bacteria, viruses are bigger or smaller?

smaller

what can the genetic material for viruses be?

have only a single type of nucleic acid—either RNA (ribonucleic acid) or DNA (deoxyribonucleic acid)

what are two examples of viral infections that the reservoir can have latent infection

1. avian influenza
2. hantavirus

Influenza has what 2 important surface proteins? What are they? How many of each type? Why is it important?

Influenza has:

* hemagglutinin (H: 16 types) and neuraminidase (N 9 types)
* 144 variations

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important because it gives all the serotypes, which means the viruses can evade past immunity that was activated, so animal bodies may not recognize it as quickly = reinfected with a different serotype

what does phenotypic expression refer to?

how a genotype is expressed. the same genotype can manifest symptoms differently

\*\*what is the difference between HPAI and LPAI? How is HPAI determined?

HPAI: highly pathogenic strains

LPAI: lowly pathogenic strains

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HPAI is determined on the strain’s tendency to kill chickens

influenza viruses evolve using what 2 methods?

1. **rearrangement** among the 6-8 strands of negative-sense RNA in the genome
2. **genetic drift**, a random process

influenza symptoms vary based on what?

strain, species, sex, and age

how are the effects of influenza different on domestic vs. wild birds?

symptoms are more severe in domestic birds than wild birds

* wild birds are more asymptomatic

what in part determines the spatial and temporal patterns of influenza in birds?

migration patterns, nesting habits, waterways

is mortality in wild birds due to influenza common? domestic birds?

not common in the wild

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common in domestic

What 2 types of birds get avian influenza the most and what’s one group of birds it rarely affects?

shorebirds and waterfowl get it the most

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rare in raptors, songbirds, and cranes

what’s the difference temporally in influenza between shorebirds and waterfowl?

shorebirds: spring and fall, absent otherwise

waterfowl: highest in late summer before first migration south, present throughout year

can avian influenza be controlled? why or why not?

* it is hard to control in wild populations
* genetic mixing creates new strands
* many virus subtypes

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where can avian influenza be found?

* Feces and contaminated water

what is an arbovirus?

an arthropod-borne virus

can mosquito larvae breathe? how?

yes, through a siphon (tube) at the surface of the water

culex is a species of what arthopod?

mosquito

\*\*what are important morphological adult characteristics of mosquitos?

* brown scales on thorax, legs, and wing veins
* brown/black scales on abdomen
* lacks ornamentation
* blunt tup of abdomen (females)

where do mosquitos spend their lives as a larva, pupa, egg, and adult?

egg, larva, pupa: water/aquatic environments

adult: everywhere else

what type of metamorphosis do mosquitos have?

complete

culex quinquefasciatus likes what kinds of conditions?

gross nitrogen rich water, urban environments

what life stage of mosquitos bites? time of day? rests where?

adults bite during the nighttime, rests indoors

what is the host for west nile virus?

birds

what is a dead-end host for west nile virus?

\`mammals

what is the genus of the primary vector of WNV?

culex

what is a bridge vector?

transfers disease from one group of animals to another, birds → mosquito → humans

what type of trap is for the culex mosquito?

* dry ice (carbon dioxide)
* light lamps and trap with carbon dioxide
* water with yeast or dry ice
* CO2 from dry ice or yeast

what is intrinsic incubation vs extrinsic?

* Intrinsic: virus replicates within host for a while before manifesting symptoms
* Extrinsic: virus replicates within vector for a while before it can be transmitted

what is haemolymph?

circulatory system of arthropods (fluids that act like blood)

where must the virus get to in the mosquito for multiplication and transmission of WNV?

the salivary glands

what is active vs. passive surveillance? what is a sentinel chicken? how does dead bird collection help with surveillance?

* Active surveillance = going out to trap and test animals
* Passive surveillance = bird collection, waiting for animals to be brought to the vet
* Sentinel Chicken: tested for antibodies at certain intervals to detect presence of disease
* Dead bird collections: analyzing dead vs live catches shows virulence of disease in species, can show if epizootic

what is dilution vs. amplification? what determines which would occur?

* Dilution: significant presence of ineffective hosts decreases transmission overall (higher diversity typically has larger distribution of species, more ineffective hosts)
* Amplification: significant presence of competent host species leads to more transmission bc hosts survive to pass disease (low diversity can lead to competent host dominance in system)

what is zooprophylaxis?

The use of other animals to divert disease-carrying insects such as mosquitos from their hosts

why use a MIR when testing mosquitoes for WNV?

* MIR= (number of positive pools)/(total specimens tested) \*1000
* Uses assumption that a positive pool contains only one infected mosquito
* Effective because uses pool testing

what type of organism causes foot and mouth disease?

a virus (SS positive sense RNA)

is foot and mouth disease a generalist or host specific virus?

generalist, large host range

Morbidity vs mortality of FMD? Which is low and which is high? Which age group is most susceptible?

High morbidity that varies by species and serotype, but mortality is low at about 2% (young are more susceptible at 20%)

is foot and mouth disease a concern in domestic animals?

Yes; can infect cattle, buffalo, pigs, sheep, goats (hoof animals) and their products can infect humans

what are some examples of active and passive surveillance we use in wildlife disease ecology?

* Active: live-trapping (healthy and sick animals), hunting for dead animals
* Passive: live-trapping (sick animals), finding dead animals

why would you need a permit in wildlife disease ecology?

to be allowed to capture or handle wildlife, to gain access to certain areas

what are the 3 Rs of the American Association for Laboratory Animal Science? What is the 4th R?

1. replacement
2. reduction
3. refinement

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4. reject

what are some ways to trap different types of animals?

* Birds: Mist nets, cannon nets
* Large mammals: dart guns, corral trap, net guns, cannon nets
* Arboreal mammals: darr gun, mist net, harp traps
* Small mammals/reptiles/amphibians: pitfall trap (with water for amphibians)

is it possible to safely take blood samples from mammals? how?

yes, from the tail vein or a careful cardiac puncture

why do we do surveillance? what are the 4 components?

to detect new disease and measure proptions of animals infected in a population:


1. **detection** of dead or diseased wild animals, collection of samples
2. **identification** of pathogens and diseases
3. **information management**, computerized records of information
4. **data analysis and communication**, maps, statistics, reports, risk analysis, meetings

what tests do we do for low prevalence diseases?

ELISA and PCR

what’s sensitivity? specificity?

* Sensitivity: proportion tested that are actually positive
* Specificity: proportion tested that are actually negative

what 3 things can a person do to protect wild endangered animals?

For safety of animal: wear a mask, keep your distance, and be vaccinated and healthy

why is keeping wildlife employees healthy important?

Not only for employees’ sake, but can also transmit disease to endangered wildlife

OneHealth uses an integrated research approach which includes what?

* Epidemiological and socio-ecological surveys
* Spatial analyses
* Observational data
* Infectious disease diagnostics/characterization
* “How are people interacting with the environment? How are domesticated and wild animals interacting?”

can people give wild animals infectious disease?

yes

what are the three main strains of Salmonella and who doe they effect?

* Salmonella pullorum: CHICKENS and turkeys
* Salmonella gallinarum: chickens and turkeys
* Salmonella typhimuirum: general vertebrates

what are the hosts of salmonella and how do they vary from domestic to wild?

found often in chickens in agricultural settings

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gulls (nesting) and songbirds (feeding)

what causes salmonellosis?

salmonella typhimurium

what are the symptoms of salmonellosis?

* Mild (birds): ruffled feathers, diarrhea, lethargy
* Severe: bacterial infections (enteritis, colitis, septicemia), abortions, esophagus lesions

what type of organism is salmonella?

bacteria, gram negative, rod shaped, fuzzy

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causes latent infection

what are serovars?

serotypes of salmonella, based on antibody or immune reactions

is there much mortality from salmonella?

rare before 1980s, increased because of agricultural conditions and the introduction of birdfeeders

Where is salmonella an emerging disease? In what species?

Urban/suburban areas; songbirds

what are the temporal patterns of salmonella?

* Flocking patterns keep it going year-round


* Fall and spring die-offs in songbirds bc of overreliance on birdfeeders
* Summer outbreaks in young gulls and terns due to close nesting sites

what is the transmission route of salmonella?

fecal-oral

What’s resource provisioning? What pathogen is known to have transmission facilitated by it? What’s an important component of it?

* Humans adding resources to the environment (providing food with birdfeeders)
* Salmonella
* Continually increases risk unless community-wide change occurs (otherwise reinfection at other sites still providing)

what changes can bird feeders facilitate in bird populations?

* Songbirds gather in close proximity, increasing contact and infection risk

what is the common name for the disease caused by bacillus anthracis?

anthrax

what is the transmission route of anthrax?

* Inoculation of soil from death → promotion of plant growth → sporulation → transmission to host

what are the common hosts for anthrax?

ungulates and grazing animals

what are the reservoirs for anthrax?

soil

what type of organism is antrax?

bacteria

What can the bacteria anthrax produce to allow it be not active and survive a long time?

spores

what are prevention methods for anthrax for domestic animals?

culling, seperation from infected

How does anthrax matter in terms of protecting endangered species? Why is species overlap a concern?

* Disproportionately affects endangered species
* Species overlap can increase spread

Why is melting permafrost an issue for anthrax spread?

Spores can survive long periods of time and will resurface/become accessible again to susceptible hosts if permafrost melts

what is the common name for the disease caused by brucella?

burcellosis

what is the transmission route of brucella?

Ingested of contaminated products, direct contact with infected or aborted tissues