Bacteria, Viruses And Animal Deseases

Question 1

How is bacteria classified ?

Answer 1

• Classified as single celled microbes, with a cell structure that is simpler than that of any other organism as there are no nucleus or membrane bound organelles.
• their control center contains genetic information in a single loop of DNA

Question 2

Name the 5 groups bacteria is classified in according to their shapes

Answer 2

Spherical(cocci)
Rod(bacilli)
Spiral(spirilla)
Comma(vibrios)
Corkscrew(spirochaete)

Question 3

What group of bacteria is responsible for nitrogen fixation ?

Answer 3

Cyanobacteria

Question 4

How are viruses classified ?

Answer 4

A virus is made up out of core genetic material,DNA or RNA, surrounded by a protective coat called a capsid made of protein.
Some surrounded by an additional spiked coat called an envelope

Question 5

Can viruses die ?

Answer 5

No because they are not alive in the first place

Question 6

How do viruses work ?

Answer 6

-The virus particle attaches to the host cell before penetrating it
- then uses the host cell’s machinery to replace its own genetic material
- once replication is completed the virus particles leave the host either by budding or bursting out of the cell(lysis)

Question 7

What are the key differences between bacteria and viruses?

Answer 7

Question 8

What are the roles of bacteria in nature ?

Answer 8

Decomposition- the breakdown of dead organic material to release nutrients like carbon back into the environment
nitrogen fixation- bacteria convert gaseous nitrogen into nitrates and nitritesas part of their metabolism, and release resulting products back into the environment
Denitrifying - opposite of nitrogen fixation, turning nitrates into nitrogen gas back into the atmosphere, deplete nutrients difficulty for crops to grow

Question 9

Name 3 African animal diseases caused by viruses and 3 by bacteria

Answer 9

Viruses
Foot and mouth
Rinderpest
Rabies

Bacteria
Anthrax
Tuberculosis
Contagious bovine pleuropneumonia

Question 10

What is a zoonotic disease ?
And give an example

Answer 10

A disease that can be transmitted from vertebrate animals to humans eg. Rabies, anthrax and ring worm

Question 11

Briefly explain the bacterial disease antrax

Answer 11

It has two states
vegetative- dormant spores in anaerobic environment(impala carcass)
infective starts as soon as spores are exposed to the atmosphere and get spread via scavengers and predators ingesting and dedicating the spores, vultures also spread them via visiting water sources after indulging on the carcass

Question 12

Briefly explain the 3 types of anthrax infections and give examples

Answer 12

Hyper acute- course of disease leas than 2 hours blood stain fluid from nostrils, mouth, anus eg impala,kudu, roan
Acute- course of diseases less than 3 days observation of signs before death, signs of depression, lagging behind witnessed eg. Zebra
Sub-acute to chronic - course of the disease past 3 days animal either recovers or dies, signs are swelling of face, throat and neck leading to breathing and swallowing difficulties eg. Omnivores and carnivores

Question 13

What are the symptoms of anthrax disease

Answer 13

Septicaemia- clotting ability of blood is impaired causing blood pooling around the carcass
bacteraemia also causes blood related problems cases an inability for blood to clot.

Question 14

Briefly explain the bacterial disease Tuberculosis

Answer 14

Caused by the genus Mycobacterium
Mycobacterium avium in birds
Mycobacterium tuberculosis is humans
Mycobacterium bovidae in ruminants

Typically only attacks host species but can spread to others like lions in the KNP

Transmission- via air, can be inhaled when an infected animal coughs
Bacteria also found in urine, Faeces and milk
Via ingestion of diseased tissue like the lungs or organs(predators)

Buffalo are the main carrier of this disease

Question 15

What are the symptoms of TB in buffalo

Answer 15

Affected animals become thin, lethargic, with a rough hair coat
Frequent cough and enlarged lymph nodes under the jaw-line

Question 16

Briefly explain Foot-and-Mouth disease(FMD)

Answer 16

Highly contagious viral disease of cloven hoofed animals
Cape buffalo considered to be major reservoirs for the virus
Virus generally spreads through inhalation but animals need to be in contact with each other for the disease to spread
Impala and kudu can also be infected
Animals tend to not die from the disease but due to secondary or acute infection in the legions of the hoof itself

Question 17

What are the symptoms of FMD ?

Answer 17

Lesions on the hoofs And mouth
Hoof lesions can cause permanent damage

Question 18

Briefly describe rinderpest

Answer 18

-Highly contagious and fatal disease in cloven hoofed animals caused by a virus
-Animals get infected through arial and fluid transmissions leading to rapid spread as specially in large herd based animals
Of about 500000 buffalo only 50 survived before rinderpest was eradicated in south africa

Question 19

What are the symptoms of rinderpest

Answer 19

-High fever
-Watery to purulent eye and nose discharge
-laboured breathing
- constipation followed by profuse watery diarrhoea
- sores on gums and tongue

Animal dies within 6-12 days due to dehydration after initial fever

Question 20

Briefly explain rabies

Answer 20

-Rabies is a deadly viral disease that affects the nervous system of warm blooded animals, including humans
- deadly zoonotic potential due to common cases in domestic and wild animals
- carried in saliva of infected animals transmission normally occurs when infected animal bites another or when there is close contact with saliva

Question 21

What species are considered major transmitters of rabies

Answer 21

The domestic dog
Yellow mongoose
Black backed jackal
Bat- eared fox
Honey badger
Small- spotted genet

Question 22

How does rabies spread ?

Answer 22

-The virus can be present in the saliva before any clinical signs are shown
- virus enters the body through a break in the skin barrier such as a bite wound
- virus taken up by the nerve supply into the nervous system finally reaching the spinal cord and the brain
- virus then populates saliva through facial nerve and salivary glands
- incubation 10-12 days could be up to a year depending on size of the bite, location of the bite and severity of the bite

Question 23

What are the symptoms of rabies ?

Answer 23

There are three stages
preliminary stage- predominate signs of behavioural change, nervous dog becomes lovable, nocturnal animals active during the day, wild animals appear tame, increase in libido, frequent urination
furious phase animal becomes irritable, restless and has exaggerated responses to visual and auditory stimuli , loose the ability to swallow causing increased salivation, some animals display mania and make unprovoked attacks on other animals and humans even inanimate objects, finally escalating to coma and death
dumb phase skip the aggressive phase and immediately become paralytic, starting at the jaw moving through the whole body
Animal becomes comatose and dies usually within four days

Question 24

Is there a treatment for rabies?

Answer 24

No there is not and the only way to diagnose rabies is to examine the brain histologically

Question 25

Briefly explain Contagious bovine pleuropneumonia (CBPP)

Answer 25

More commonly known as lung disease or lung plaque
Recorded in the Okavango
Occurs mainly in cape buffalo and cattle
Spread via droplets of fluid shared through close contact such as herding, sharing of drinking points
Can spread rapidly in a heard and only be seen weeks or months later

Question 26

What are the symptoms of Contagious bovine pleuropneumonia(CBPP)

Answer 26

-Pneumonia and inflamed lung membranes
- lung lesions causing fever, listlessness and breathing problems
- moist cough and nasal discharge
- infrequent coughing in sub acute cases
- frequent coughing when animal attempts to stand up in acute cases
- arthritis but no lesions in young animals