Epidemiology? Flashcards
What are dead end hosts?
A host from which infectious agents are not transmitted to other susceptible hosts. One in which the life cycle will not be completed.
What are 5 examples of zoonoses in which humans are accidental dead-end hosts?
- Cystic echinococcosis (Echinococcus granulosus)
- Alveolar echinococcosis (Echinococcus multilocularis)
- Porcine cysticercosis (Taenia solium)
- Trichinosis (Trichinella spiralis)
- Toxoplasmosis (Toxoplasma gondii)
What are 5 examples of animal epizootics and panzootics?
- Highly Pathogenic Avian Influenza H5N1 (Bird ’flu, global 2003 – present)
- African Swine Fever (Russia/Europe 2007– present)
- Bluetongue (N. Europe & UK 2007 – 2008)
- Foot and Mouth Disease (UK 2001)
- Rinderpest (UK 1745, 1865; Africa 1887) – which is the 2nd worldwide eradicated disease after small pox (only small pox and rinderpest)
Distinguish enzootic and epizootic diseases.
Endemic/enzootic is always present in a population at a relatively constant level. Epizootic/epidemic is when a disease is very low or non-existent in a population and then suddenly a very high level/non-constant level.
What are neglected zoonosis?
Not a lot of money is spent on controlling them. Many vets say that if the main problem with a disease it should be medics to sort it out and vice versa despite reservoir being in animals sometimes.
What is DALYs, disability adjusted life years?
- Measure of overall disease burden
- Number of years lost to ill health, disability or early death
- Used in public health and health impact assessment
- DALY’s derived from: ‘Years of Life Lost’ (YLL) and ‘Years Lived with Disability‘ (YLD)
- DALY = YLL + YLD
- zDALY: factors in animal health losses by estimating time required to earn the income needed to replace that financial loss: animal loss equivalence (ALE)
What is zoonosis emergence linked to?
Agricultural intensification and environmental change.
List the important bacterial zoonoses.
Anthrax
Brucellosis
Bovine tuberculosis
Bubonic plague
Campylobacteriosis
Coxiellosis (Q fever)
Leptospirosis
Listeriosis
Lyme borreliosis
Salmonellosis
List the important parasitic zoonoses.
Alveolar Echinococcosis – echinococcus multiocularis
Cystic echinococcosis – echinococcus granulosus
Cysticercosis
Leishmaniasis
Toxoplasmosis
Trichinellosis
Trypanosomiasis
Describe African trypanosomiasis in humans.
- Trypanosoma brucei
- Sleeping sickness
- Invariably fatal
- Acute and chronic forms
Describe African trypanosomiasis in animals.
- Wildlife reservoir – antelope, buffalo, warthog
- Domestic cattle increasingly important reservoir
- Treatment of cattle to control human disease – pour on and hand spraying
How is Leishmania strongly affected by climate change?
Changes in temperature, rainfall and humidity can alter distribution, survival and population size of sandflies and reservoir hosts.
Small fluctuations in temperature can have profound effect on developmental cycle of Leishmania in sandflies, allowing transmission of the parasite in previously non-endemic areas.
Drought, famine and flood can lead to the massive displacement and migration of people to areas with transmission of Leishmania.
What are the objectives of parasites control in populations?
- Eliminate parasites for some greater good
- Suppress infection pressure to reduce overall clinical incidence
- Maintain levels of infection below those that cause production loss
- Protect humans from zoonotic parasites
What are the trade offs between level of control and its efficiency?
Economics
Immunity
Compliance
Sustainability
Co-infection
Describe economic trade off.
- Cost of antiparasitic agents
- Cost of administration, especially in farmed animals: need to gather and restrain animals. May be combined with other management procedures, such as weighing and housing.
- Benefit-cost analysis
