Friday, 24 May 2019

What are Zoonoses?

Zoonoses: Infections acquired from animals. By direct contact. Indirect contact by vector. Indirect contact through environmental contamination.

Zoonosis refers to diseases that can be passed from animals to humans. They are sometimes called zoonotic diseases. Animals can carry harmful germs, such as bacteria, fungi, parasites, and viruses. These are then shared with humans and cause illness
Animals can carry harmful germs, such as bacteria, fungi, parasites, and viruses. 

These are then shared with humans and cause illness. Zoonotic diseases range from mild to severe, and some can even be fatal.

Before the introduction of new hygiene regulations around 100 years ago, zoonotic diseases such as bovine tuberculosis, bubonic plague, and glanders caused millions of deaths. They are still a major problem in developing countries.

Rabies
Rabies is a disease that affects the nervous system of mammals. It is usually caused by a virus and is transmitted if an infected animal bites a person or other animal.
Rabies is almost always fatal once symptoms appear. However, rabies vaccines exist and are commonly available.

Lyme Disease
Lyme disease and Rocky Mountain spotted fever
Lyme disease is transmitted through tick bites. Symptoms can range from mild to severe, but it can be treated using antibiotics.
Dengue, malaria, and chikungunya
These are mosquito-borne diseases and are more common in certain areas, such as the Caribbean.
Symptoms include fever, vomiting, and headaches. It is vital to treat these conditions as soon as possible, as they can be fatal.

Salmonella infection
Salmonella is often caused by handling reptiles or amphibians that carry Salmonella, or by handling baby chicks or ducks.
The illness usually lasts for between 4 and 7 days, and symptoms include diarrhea, fever, and abdominal cramps. People can usually recover without medical treatment, although conservative measures are recommended.
E. coli infection
This infection is often caused by touching infected animals or handling contaminated food. Cows also have E. coli germs on their udders.

**!!REMEMBER TO STAY POSITIVE LIKE A PROTON!!**

Saturday, 4 May 2019

How microorganisms enter a host and how they damage host cells with exotoxins?

How microorganisms enter a host and how they damage host cells with exotoxins?

To cause disease most pathogens must: 
 gain access to the host 
 gain access to the tissue
 evade host defences 
 damage the host tissue 

• Some microbes cause disease without invading the body • Portals of entry - gaining entrance to the human body (and other hosts) through several avenues
Adhesins/ligands bind to receptors on host cells
The host cell cytoskeleton provides the mechanism: • Actin is used:  to penetrate host cells  to move through and between host cells
Invasins – Salmonella alters host actin to enter a host cell
Use actin to move from one cell to the next – Listeria
Cadherin: bridges membrane junctions
Exotoxins 

• Antibodies: 
 provide immunity to exotoxins • Inactivated exotoxins: 
 can no longer cause disease 
 can still stimulate the body to produce exotoxins 

• These altered exotoxins are called toxoids 
 toxoids (as vaccines) stimulate antitoxin production (immunity) 
 Vaccines – stimulate antitoxin production
Exotoxins 

• Are named on the basis of many characteristics: 
 neurotoxins - nerve cells 
 cardiotoxins - heart cells
 hepatotoxins - liver cells 
 leukotoxins - leukocytes 
 enterotoxins - the lining of the gastrointestinal tract 
 cytotoxins - a wide variety of cells diphtheria toxin (cause of diphtheria) botulinum toxin (Clostridium botulinum) vibrio enterotoxin (Vibrio cholerae)

**REMEMBER TO STAY POSITIVE LIKE A PROTON!!**