Understanding Zoonosis: The Study of Transmissible Diseases and Infections

Sarah Ahmed, MD., PhD., George Tarabelsi, MD., Zara Khan, MD., Shubhankar Joshi, MD., PhD., Francesca Corsini, MD., PhD., Megi Resulaj, MD., PhD.College of Science and Mathematics, University of Massachusetts Boston

H5N1 (Avian Influenza)H5N1 (Avian Influenza)

H1N1 Virus (Swine Flu)H1N1 Virus (Swine Flu)

Rationale Rationale

References References

EbolaEbola

Future DiscussionFuture Discussion

Special AcknowledgmentsSpecial Acknowledgments

Zoonosis is a disease or infection that is natur

ally transmissible from vertebrate animals to humans, and vice-versa. The disease is caused by all types of pathogenic agents, including bacteria, parasites, fungi, and viruses. Humans can get zoonotic diseases by coming into contact with the

infected live poultry, rodents, reptiles, amphibians, insects, and other domestic and wild animals. Anyone who has contact with animals can get a zoonotic disease, but

people may be more at risk than others. These include people with a weakened immune system, children age 5, the elderly, and pregnant women. About 75% of recently emerging infectious diseases affecting humans are diseases of animal

origin, and approximately 60% of all human pathogens are zoonotic.

There are four steps of a zoonotic infection:1. Exposure to the virus 

Contact between donor and recipient hosts is required for transfer of the virus.

2. Infection by the virusIn order to infect a new host, the virus must be able to efficiently infect the

appropriate cells of the new host, and that process can be restricted at many different levels. Therefore, exposure to the virus must be plentiful in order to increase the chance that the virus will infect the cell that it needs to infect. 

3. Spread of the virus to other members of the populationPopulation density plays a large role in the exposure to a virus, as well as

the occurrence of epidemics. This is because the virus is able to find many new hosts to infect in a dense population and can use those hosts for

reproduction even if the original host has died from infection.

4. Adaptations that the virus acquires in order to infect more effectively.While a certain virus may effectively infect a host and spread throughout a

population, its survival is not ensured, especially when considering the current advances in medicine that can prevent infection and kill an existing virus in a host. Therefore, it must acquire adaptations that will increase its

chances of survival.

IntroductionIntroduction

- 4 ways in which one can be infected by zoonotic disease: exposure to the virus, infection by the virus, transmission of the virus to members of the population, and the adaptations the virus makes to infect others

more effectively- While we have advanced in understanding the affects of the virus,

there are certain aspects that we must continue to explore: the study of when and where the virus forms, what it is that causes the spread of

the virus, and how we can limit the virus' natural reservoir, which would in turn, limit the spread of the virus.

- The development of a zoonotic disease occurs through the exchange between humans and animals, and as a first defense against the

development of these diseases the exchange of bodily fluids between humans and animals must be addressed. Not only to be sure that the exchanges are humane, but also done cleanly in order to deter any

more diseases from developing.

Conclusion Conclusion

WHAT IS IT?- It is a highly pathogenic avian bird flu virus- Caused outbreaks in parts of Asia and the Middle East over domestic poultry- First detected in China in 1996 from a goose.- There have been about 650 human cases reported from 15 different countries since 2003.- Mortality rate is about 60% of those infected with the virus.

SYMPTOMS & COMPLICATIONS OF THOSE INFECTED WITH H5N1:• Fever and cough• Acute respiratory distress• Abdominal pain• Diarrhea• Pneumonia• Respiratory failure• Altered mental state• Seizures• Failure of multiple organs • Death

TREATMENT AND VACCINATION:- Two antiviral medications previously licensed by the FDA have shown resistance to HPAI H5N1- It has been recommended to use either oseltamivir (preferred) or zanamivir.

ZOONOTIC SPREAD OF AVIAN INFLUENZA:There are three different barriers that a virus must overcome in order to spread from one species to another.1. Cross-species host-host interaction

The species from which the virus originated and the species that received the virus would have to interact first.

2. Virus-host interactionsThe ability of the virus to infect the nest host species3. Intraspecies host-host interactionsTransferring the virus between infected and non-infected hosts within the species

http://www.thejakartapost.com/news/2012/01/10/bird-flu-threat-still-lurking-jakarta0.htmhttp://rccp.udea.edu.co/index.php/ojs/article/view/742/730http://www.flu.gov/about_the_flu/h5n1/http://www.cdc.gov/flu/avianflu/h5n1-virus.htm

Link: http://www.flu.gov/about_the_flu/h1n1/"H1N1 (originally Referred to as Swine Flu)." H1N1 (Swine Flu). U.S. Department of Health & Human Services, n.d. Web.

What is it?• A respiratory illness found in pigs• An Orthomyxovirus that contains:

• Haemagglutinin – glycoprotein causing red blood cells to clump together and then binding the virus to the red blood cell

• Neuraminidase – enzymes that assist in transferring the virus particles through the infected cell

• The virus appeared to be a new strain of H1N1 which resulted to be a triple re-assortment of bird, swine, and human flu

How is it spread?• Through airborne droplets (coughing

or sneezing) of an infected animal • Can be transmitted through hand-

eye, nose, or mouth contactPrevention and Treatment:• No known treatment• Preventative care includes flu

vaccination and proper personal protective equipment

We chose to investigate zoonosis because of the recent attention it has received in the news and media, specifically in cases of Ebola, H5N1, and H1N1. We wish to explore the biological mechanisms which allow these viruses to expand their host range. In addition, some of our examples also illustrate the wide range of consequences these viruses can exhibit, from mild to detrimental.

-Do animals show the same symptoms for the disease as humans?-What is the body’s initial response to the diseased cell? Do the cells go undetected?-What are some ways researchers are trying to find a cure for these diseases?

We are thankful to Sanofi Genzyme and Dean Andrew Grosovsky for making this possible.

WHAT IS IT?• A virus that is transmitted from animals to humans via blood contact with an infected animal host and lesions in the hands of a human

• It's transmitted from human to human through direct contact • with blood or bodily fluids from another infected person• Ebola is a threat to patients and doctors dealing with the disease because it has killed 90% of those infected

THE ZOONOTIC SPREAD OF EBOLA:• The disease originates from an individual coming into contact with the excretions or blood from animals infected with the disease

• Coming into contact with the bodily fluid of an infected individual spreads the disease from human to human• Can be spread via contaminated medical equipment